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  • 1
    Publication Date: 1974-07-01
    Description: Lineamentschnittpunkte humider und semi-arider Klimabereiche werden beschrieben, untersucht und im Hinblick auf ihr Vorkommen und ihre Erscheinungsformen sowie in bezug auf ihr Verhältnis zur Mineralisation verglichen. Für jeden Bereich werden die mineralisierten Schnittpunkte zunächst miteinander, dann mit sterilen Schnittpunkten verglichen. Während Lineamentschnittpunkte im feuchten Klima recht komplex sind und aus einer Ansammlung mehrerer Schnittpunktsysteme bestehen (eventuell mit einer Lagerstätte im Umkreis von mehreren Kilometern um eines dieser Sekundärzentren), wurden die Schnittpunkte im semi-ariden Klima bis jetzt als ziemlich einfach und im Gelände sehr scharf hervortretend angesehen (mit einer Lagerstätte höchstens 0–1 km vom Zentrum entfernt). Diese Beobachtung ist weiterhin gültig, aber der scheinbare Widerspruch wird aufgehoben, wenn man — aufgrund von Erfahrungen, die im feuchten Bereich gewonnen wurden — annimmt, daß die Achsen der sehr breiten sandigen Täler des semi-ariden Geländes zweifellos bedeutende Lineamente darstellen. Daraus ergibt sich, daß Schnittpunkte solcher Lineamente Millionen von Jahren verdeckt waren und nur die weniger bedeutenden Schnittpunkte, die jetzt noch in den erodierten Gebirgsabschnitten zu sehen sind, übrigblieben. Es ist daher anzunehmen, daß Lagerstätten in diesem Milieu in unmittelbarer Nähe von Lineamentschnittpunkten zweiter oder dritter Ordnung vorkommen, die meist durch gut ausgeprägte Verwerfungen in Erscheinung treten. Eine Revision der Lineamenttheorien semi-arider Klimabereiche ist vor weiteren Deutungen nötig. Ein praktischer Hinweis für den Aufschluß von Lagerstätten im humiden Bereich kann durch die Tatsache gegeben werden, daß die Elemente von Lineamentstrukturen hier viel leichter zu erkennen sind als im semi-ariden Bereich.Краткое содержаниеОписаны и исследован ы точки пересечения л инеаментов гумидных и полуаридн ых климатичемких зон и с опоставлены их прояв ление, форма и связь с минерализациями. В то время, как точки пе ресечения линеамент ов влажного климата очень сложны и составлены с коплениями нескольк их систем их — порой с залежами полезных ископаемых, распологающимися во круг одного из этих вторичных центров на многие кил ометры, — известные на м до сих пор точки пересечения линеаментов полу-ари дного климата сравни тельно просты и выделяются с реди ландшафта, а залежи по лезных ископаемых располагаются здесь на расстоянии от центра в 0–1 км. Эти вы воды сохраняют свою с илу и на будущее, Кажущееся прориворечие устран яется, если на основан ии наблюдений, собранны х в гумидной зоне, предп оложить, что оси очень широких песчаных долин полуа ридных районов бессомнения представляют собой в едущие линеаменты. Отсюда следует, что то чки пересечения лине аментов оказываются скрытым и миллионы лет и остают ся только некоторые, н аиболее выделяющиеся, залега ние которых видно в эроди рованных горах. Поэто му можно предполагать, что в этой среде, в непосред ственной близи точек пересечения линеаме нтов второго или третьего порядка, проявляющимися хоро шо выраженными сбросам и, находятся залежи пол езных ископаемых. Нео бходимо провести ревизию тео рии линеаментов полу-ари дных климатических з он, а только тогда можно будет делать дальнейшие вы воды. Практическое указан ие на залежи полезных ископаемых в гумидных районах можно получить из тог о факта, что элементы линеаментных структ ур устанавливать здесь легче, чем в полу-аридных районах.Lineament intersections of the humid and semi-arid climates are described, analyzed and compared as much for their occurrences and patterns exhibited as for their relationship to mineralization. For each environment, the mineralized intersections are compared with each other first, then compared with barren intersections. While lineament intersections in a humid climate are quite complex, being formed by an aggregation of several “sub-intersections” (with a mine that may occur within several kilometers from one of these secondary centers), the intersections in the semiarid climate were until this time considered to be rather simple and very sharply marked in the field (with a deposit that may occur from 0 to 1 kilometer at the most from a center). This observation remains valid but the apparent contradiction resolves itself when it is accepted, from experience gained in the humid environment, that the axes of the very broad sandy valleys of the semi-arid country without any doubt must represent lineaments of major importance. It results that intersections of such lineaments have been buried for millions of years, leaving only those intersections of lesser importance still visible now on the eroded mountains. Mining deposits in this environment must therefore be considered as occurring around and very close to lineament intersections of a secondary or third order represented most of the time by well-marked faults. A revision of the lineament theories in the semi-arid climate is in order prior to any further interpretation. A mining exploration technique in the humid environment can tentatively be presented by the fact that the elements of lineament structure are so much more easily detected than in the semi-arid environment.RésuméLes intersections linéamentaires du milieu humide et du milieu semi-aride sont décrites, étudiées et comparées ici, tant du point de vue de leur occurrence et des configurations qu'elles présentent que du point de vue minéralisation. Pour chacun des deux milieux, les intersections minéralisées sont comparées entre elles d'abord, puis comparées à des intersections stériles. Tandis que les intersections linéamentaires du climat humide sont très complexes, se composant de plusieurs « sub-intersections » (avec une mine qui pourrait se trouver à quelques kilomètres d'un des centres secondaires), les intersections du climat semiaride étaient considérées jusqu'à ce point comme étant assez simples et très bien marquées sur le terrain (avec un dépôt minier se présentant de 0 à 1 kilomètre au maximum du centre). Cette observation est toujours valide mais il existe une contradiction apparente qui se résoud lorsque l'on accepte, avec l'expérience gagnée dans le milieu humide, que les axes des très larges vallées sableuses du milieu semi-aride doivent sans aucun doute représenter des linéaments majeurs. Il en résulte que les intersections de ces linéaments ont été ensevelies depuis des millions d'années, ne laissant guère que des intersections de moindre importance encore visibles à présent sur les montagnes érodées. Les gisements miniers dans ce milieu doivent alors être considérées comme « gravitant » autour et très près d'intersections linéamentaires d'ordre secondaire ou ternaire représentées la plupart du temps par des failles très nettes. Une révision de la théorie linéamentaire dans le pays semiaride s'avère donc nécessaire avant d'aborder une interprétation finale. A titre pratique, une méthode d'exploration minière est présentée pour le milieu humide où les éléments de structure linéamentaire se décèlent avec bien plus de certitude que dans le milieu semi-aride. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 2
    Publication Date: 1974-01-01
    Description: кРАткОЕ сОДЕРжАНИЕОпИсАНА „Mullion-Struktur“ Иж склАД ЧАтОгО АМФИБОлИтА МО ЩНОстьУ В НЕскОлькО МЕтРОВ НА УгО-ВОстОкЕ ДОкЕМБРИИскОгО ФУНД АМЕНтА НОРВЕгИИ. ОсИ жДЕсь ОтклОНьУтсь НА 60–70‡ От ОсИ склАДЧАт Ост И, кОтОРУУ МОжНО ВОсстАНОВИть НА ОсНОВАНИИ БИОтИтО Вых РАжлИстОВАНИИ В А МФИБОлИтЕ. ЁтА Ось склАДЧАтОстИ пОВтОРьЕтсь тАкжЕ РО гОВыМИ ОБМАНкАМИ. пРЕ ДпОлАгАУт, ЧтО ЁтИ стРУктУРы ОБРАжОВАлИсь НА НЕсО глАсНО жАлЕгАУЩЕИ пО ВЕРхНОстИ (ВЕРОьтНО, пОВЕРхНОст И ИжлОМА). НА ЁтОИ пОВЕРх НОстИ ОсИ стРУктУР пР ОхОДьт пАРАллЕльНО сО слЕДОМ РАжлИстОВАНИ ь АМФИБОлИтА. ЁтИ стРУ ктУРы ОБРАжОВАлИсь ОДНОВР ЕМЕННО с лИНЕИНыМИ РОгОВыМИ ОБМАНкАМИ В РЕжУльтА тЕ ДВИжЕНИь ВДОль пЕРЕсЕкАУЩИхс ь плОскОстЕИ РАжлИстО ВАНИь.A mullion structure is described from a several meter thick amphibolite from the Precambrian bedrock of south-eastern Norway. The mullion axes deviate about 60–700 from the fold axis defined in the amphibolite by the constructed intersection of foliation planes. The fold axis is also reflected in the lineated hornblende grains. The orientation of the mullion axes is parallel to the trace of the amphibolite foliation on the mullioned surface. It is concluded that the mullions were formed on a discordant surface (probably a fracture surface) in responce to movement along the intersecting foliation planes at the same time as the hornblende lineation was developed.RésuméUne structure en «mullion» a été étudiée dans des amphibolites, d'âge Précambrien, en Norvège. Les mullions proviennent d'une couche discordante, qui a été déformée avec les amphibolites. On observe que les axes des mullions font une angle de 60 à 70 degré avec la linéation (prismes de hornblende) qui est parallèle aux axes des plis; les axes des mullions et la linéation sont situés dans le plan de la foliation des amphibolites.ZusammenfassungAus dem südostnorwegischen präkambrischen Grundgebirge wird aus einem mehrere Meter mächtigen verfalteten Amphibolit eine Mullion-Struktur beschrieben. Die Achsen der Mullions weichen 60–700 von der Faltenachse ab, welche aufgrund der Biotitfoliationen im Amphibolit konstruiert werden konnte. Diese Faltenachse wird auch von den linearen Hornblenden nachgezeichnet. Es wird angenommen, daß sich die Mullions auf einer diskordanten Fläche (wahrscheinlich einer Bruchfläche) gebildet haben. Auf dieser Fläche verlaufen die Mullion-Achsen parallel der Spur der Amphibolit-Foliation. Die Mullions entstanden gleichzeitig mit den linearen Hornblenden infolge einer Bewegung entlang der sich schneidenden Foliationsebenen. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 3
    Publication Date: 1974-07-01
    Description: Erläutert wird die Genese synorogener varistischer Magmatite des Bergsträßer Odenwaldes, die zwischen steilgestellten Zonen alter Metamorphite auftreten (Kulissenbau). Der Altbestand setzt sich vorwiegend aus Schiefern und schieferigen Gneisen (Schiefergneisen) zusammen, die teilweise plagioklasblastisch verändert sind. Die Magmatite werden in eine frühorogene Hornblendebasit-Serie (Gabbro → Diorit) und eine hochorogene Biotitflasergesteins-Serie (Diorit → Granit) unterteilt. Beide Serien sind intrusiv. Die Hornblendebasit-Serie besteht aus syntektisch differenzierten Gliedern eines nicht näher bekannten Magmas. Bei der Biotitflasergesteins-Serie kann eine lithogene Herkunft nachgewiesen werden (Gneis → Metablastit → Flaserdiorit/granit). In der hochorogenen Phase entwickeln die Gesteine — infolge der Durchbewegung während der Platznahme — eine stratiforme Ausbildung. Unterschiedliche Strukturen werden angeglichen, und es entstehen protoklastische bis primärgneisige Gewebe. Das in dieser rheomorphen Bildungsphase geprägte Kristallin nennen wir kurz das ‚'Synorogen“. Die Diorite der beiden Serien sowie Produkte einer Dioritisierung in situ werden verglichen. Sie alle bilden zueinander konvergente Strukturen. Der mobile Zustand bei Dioritisierung und Granitisierung verlangt eine erneute Diskussion des ‚'ultrametamorphen Bereichs“.The genesis of synorogeneous, variscian magmatites from the Bergsträsser Odenwald is explained. They are alternating with steep, old metamorphic rocks (schists and schisteous gneisses, partly transformed to plagioclase-blastites). The magmatites are differentiated into an early-orogenic hornblende-basiteseries (gabbro → diorite) and a high-orogenic biotite-flasermagmatite-series (diorite → granite). The hornblende-basite-series is “normally intrusive” with differentiated syntectic members; the biotite-flasermagmatite-series is lithogenic and has been formed by plagioclase-blastesis and anatexis. At the transition to the high-orogenic phase the rocks develop a strong gneissose foliation (due to movements during the emplacement). The structures assimilate, and a protoclastic to primary-gneissic texture is formed. We name the crystalline in this periode of formation briefly “Synorogen”. The diorites from the two series, as well as the dioritoids and aorites (products of “dioritisation”) show converging structures within the Synorogen. The mobile (ultrametamorphic) stage during the dioritisation and granitisation is discussed.RésuméExplication de la genèse des roches magmatiques synorogènes hercyniennes du Bergsträsser Odenwald. Ces roches alternent avec des roches métamorphiques anciennes en position verticale (structure en coulisse). Les roches métamorphiques sont constituées principalement par des schistes et des gneiss schisteux montrant localement une blastèse du plagioclase. Les roches magmatiques sont subdivisées en deux séries orogéniques qu'on peut bien distinguer par la présence de mafites différents. La première série est basique (Gabbro → Diorite) et caractérisée par la dominance d'amphibole. La deuxième série (tardive) est acide (Diorite → Granite) et caractérisée par l'abondance de biotite et le développement d'une texture rhéomorphe (Flasertextur). La première série montre tous les caractères d'une mise en place normale par intrusion et d'une différentiation modifiée par syntexis. La deuxième est palingénétique et résulte de processus anatectiques précédés d'une blastèse des plagioclases. Les roches intrusives de la série orogénique tardive montrent une texture stratiforme (due au processus rhéomorphique lors de la mise en place; les structures s'assimilent et on arrive à une formation de textures protoclastiques (gneiss primaires). Le cristallin hercynien formé dans cette phase est nommé le « Synorogène ». Les diorites des deux séries ainsi que les dioritoides et aorites (produits de la dioritisation) montrent des structures convergentes dans le synorogène. L'état de la partie mobile (ultramétamorphique) lors de la dioritisation et granitisation est discuté.Краткое содержаниеРассмотрен генезис с инорогенных магмати тов Оденвальда, выступаю щих среди возвышающихся зон древних метаморф итов (кулисы). Древние породы представлены приему щественно сланцами и сланцеватыми гнейса ми, частично плагиокластически п реобразованными. Магматиты подраздел яют на серию раннеоро генных роговообманочных ба зитов (габбро → диорит) и сери ю биотит-флазерных по род (диорит → гранит) периода кульминацио нной фазы орогенеза. О бе серии –интрузивы. Серия роговообманковых ба зитов состоит из синт актически деформированных ком понентов некой точно ещё не оха рактеризованной маг мы. Серия биотитфлазерных пород, вероятно, осадо чного происхождения (гнейс → метабластит → флазер диорит/гранит). Породы, образовавшиеся в пер иод кульминационной фазы орогена проявляют в результате движени й во время размещения, стратиформное строе ние. Здесь имело место уравнива ние различных структ ур, при этом появились образован ия от протокластически х до первично-гнейсов ых. Кристаллины, появивш иеся в этой фазе реоморфног о преобразования, наз ывают здесь „синорогеном“. Сравнены диориты обе их серий, как и продукт ы диоритизации Все они образуют сближающие ся структуры. нестаби льное состояние при диорит изации и гранитизации вызыв ает необходимость ди скуссии о „ультраметаморфных участках“. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 4
    Publication Date: 1974-01-01
    Description: Les chitinozoaires déterminent l'âge géologique des schistes de Soom à la base de la formation de Cedarberg en Afrique du Sud comme allant du Silurien inférieur jusqu'à l'Ordovicien supérieur, l'âge le plus ancien étant le plus probable. Le niveau de l'éométamorphisme organique dans les schistes de Soom pourrait correspondre à un enfouissement d'un peu plus de 5000 métres.ResumenLa edad geológica de las pizarras Soom (base de la formatión de Cedarberg, áfrica del Sur) es determinada por los quitinozoos como SilÚrico inferior a Ordovícico superior, siendo esta Última la más probable. Por medio del nivel de eometamorfismo orgánico se estima que las pizarras Soom se hallaban cubiertas por terrenos de mas de 5000 metros de espesor.ZusammenfassungDas Alter der Soom-Schiefer an der Basis der Cedarberg-Formation in Südafrika wurde mit Hilfe von Chitinozoen als unteres Silur bis oberes Ordovizium bestimmt, wobei das höchste Alter am wahrscheinlichsten ist. Die Höhe des organischen Eometamorphismus in den Soom-Schiefern würde einem Gebirgsdruck von wenig mehr als 5000 Metern entsprechen.Chitinozoans bracket the geological age of the Soom Shale at the base of the Cedarberg Formation of South Africa as Lower Silurian to Upper Ordovician whereby the oldest age is the more probable. On account of the organic eometamorphism the most likely maximum depth of burial of the Soom Shale was slightly in excess of 5000 meters.кРАткОЕ сОДЕРжАНИЕпО хИтИНОжОьМ ОпРЕДЕ льУт ВОжРАст Soom — слАНц ЕВ У БАжИсА ФОРМАцИИ сЕДАРБЕРг В УжНОИ АФР ИкЕ, кАк НИжНИИ сИлУР Д О ВЕРхНЕгО ОРДОВИкА, пРИЧЁМ пЕРВыИ кАжЕтсь НАИБО лЕЕ ВЕРОьтНыМ. ВысОтА ОРгАНИЧЕскОг О ЁОМктАМОРФИжМА В Soom-с лАНцАх сООтВЕтстВУЕт, тАкИМ ОБРАжОМ, гОРНОМУ ДАВл ЕНИУ НЕ БОлЕЕ 5000 М. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 5
    Publication Date: 1974-01-01
    Description: кРАткОЕ сОДЕРжАНИЕгРАФИЧЕскИЕ ИжОБРАж ЕНИь сООтНОшЕНИИ ОсЕ И X/Y И Y/Z ДЕФОРМИРОВАННых кВАРцЕВых И кВАРцИтО Вых гАлЕк ОпИсыВАУт И х пОлОжЕНИЕ В кОНстРИкцИОННОМ пОлЕ. пРИ сРАВНЕНИИ ДА ННых НАБлУДЕНИь И тЕО РЕтИЧЕскИх МОДЕлЕИ ОБНАРУжИлИ, ЧтО ОкОНЧАтЕльНыЕ ОЧ ЕРтАНИь ДЕФОРМИРОВА ННых гАлЕк с ЁллИпсОИДОМ ДЕФОРМА цИИ кОНстРИктОВНОгО тИп А пОлУЧАУтсь пРИ НАлО жЕНИИ ДЕФОРМАцИОННОИ ФАжы F2, ВыжыВАУЩЕИ слАНцЕВ АтОсть, с РАжглАжИВАУ ЩИМ тИпОМ НА пОкРОВООБРАжУУЩУ У ДЕФОРМАцИОННУУ ФАжУ F1 с РАжглАжИВАУЩИМ тИ пОМ. ФОРМы гАлЕк гОВОРьт О тОМ, ЧтО глАВНОЕ НАпР АВлЕНИЕ НАИБОльшЕгО пРОстИРАНИь (X) кОНЕЧНО гО ЁллИпсОИДА ДЕФОРМАц ИИ лЕжИт пАРАллЕльНО, ИлИ пОЧтИ ЧтО пАРАллЕльНО с НАпРАВлЕНИЕМ ОсЕИ ск лАДОк F2 И F3.RésuméLes diagrammes de rapports d'axes X/Y et Y/Z relatifs à la déformation de galets de quartz et de quartzite montrent une localisation dans un champ de constriction. En comparant les données de l'observation avec des modèles théoriques on voit que les contours des galets déformés suivant un ellipsoÏde de déformation du type constriction résultent de la superposition de la phase de déformation F2, du type applatissement, déterminant la schistosité, sur la phase de déformation F1, du mÊme type, liée aux nappes. Les contours déformés des galets montrent que la direction principale de la plus grande extension (X) de l'ellipsoÏde de déformation affine est parallèle, ou approximativement parallèle, à la direction des axes des plis F2 et F3.The plots of axial ratios, X/Y and Y/Z, of deformed pebbles of quartz and quartzite occupy the constriction field. It is proved by comparision of observed data with the theoretical models, that the finite shapes of deformed pebbles showing constriction-type deformation ellipsoid has resulted due to superimposition of the schistosity forming flattening-type deformation of F2 phase on the nappe forming flattening-type of F1 deformation phase. The deformed shapes of pebbles indicate that the principal direction of maximum extension (X) of the finite deformation ellipsoid lie parallel to subparallel to the axial directions of F2 and F3 folds.ZusammenfassungDiagrammdarstellungen der Achsenverhältnisse X/Y und Y/Z ergeben für deformierte Quarz- und Quarzitgerölle eine Lage im Konstriktionsfeld. Durch Vergleich der Beobachtungsdaten mit theoretischen Modellen wird nachgewiesen, daß die finiten Umrisse deformierter Gerölle mit einem Deformationsellipsoid vom Konstriktionstyp sich aus der überlagerung der die Schieferung verursachenden Deformationsphase F2 mit Plättungstyp über die deckenbildende Deformationsphase F1 mit Plättungstyp ergaben. Die deformierten Umrisse der Gerölle zeigen, daß die Hauptrichtung größter Extension (X) des finiten Deformationsellipsoides parallel oder annähernd parallel zur Achsenrichtung der F2- und F3-Falten liegt. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 6
    Publication Date: 1974-01-01
    Description: La Ceinture Pyritique hispano-portugaise s'étend dans le SW de la Peninsule Ibérique dépuis Seville jusqu'à la cÔte ouest du Portugal. Les réserves totales représentent environ 1.000 millions de tonnes de sulfures massifs avec une teneur moyenne de 46% S, 42% Fe, 2–4% Cu+Pb+Zn. Les gÎtes stratiformes de sulfures massifs et les minéralisations de manganèse qui les accompagnent sont d'origine synsédimentaire-exhalative. Ils sont encaissés dans une série volcano-sédimentaire, géosynclinale du Carbonifère Inférieur, fortement plissée durant l'Orogenèse hercynienne. Un bref aperÇu de la géologie régionale de cette province métallifère est presenté, et la géologie de trois districts miniers décrite: Lousal (Portugal), La Zarza et Tharsis (province de Huelva, Espagne). L'accent est mis sur l'étroite relation existant entre les minerais sulfurés et manganeux et le volcanisme alcalino-acide sousmarin. L'activité solfatarique est responsable de la formation des sulfures au cours des derniers stades des émissions volcaniques acides. Les concentrations de minerais de gros gisements de sulfures (lentilles atteignant 100 millions de tonnes de minerai massif) ont été accumulées par apport de boues et/ou de débris de sulfures dans des dépressions nouvellement formées dans une topographie du fond sousmarin en continuel changement par suite de mouvements volcano-tectoniques. Cette opinion se déduit des structures sédimentaires du minerai et de ses structures internes géochimiques.кРАткОЕ сОДЕРжАНИЕИспАНскО-пОРтУгАльс кИИ пОьс кОлЧЕДАНА пР ОстИРАЕтсь НА УгО-жАпАДЕ ИБЕРИИс кОгО пОлУОстРОВА От сЕВИл ьИ пОЧтИ ЧтО ДО жАпАДН ОгО пОБЕРЕжьь пОРтУгАлИ И. ОН сОДЕРжИт пРИМЕРНО 1000 Мл Н. тОНН МАссИВНых кОлЧ ЕДАННых РУД с пРИБлИжИтЕльНО И пРИМЕсьУ: 46% S, 42% Fe И 2–4% Cu+Pb+Zn. слОИстыЕ кОлЧЕДАННы Е РУДНыЕ МЕстОРОжДЕН Иь И сОпРОВОжДАУЩИЕ Их МЕ стОРОжДЕНИь МАРгАНцА ОкАжыВАУтс ь сИНсЕДИМЕНтАцИОННО-ЁксгАльцИОННОгО пРО ИсхОжДЕНИь И ВстРЕЧАУтсь В гЕРцИ НскОИ склАДЧАтОИ, НИжНЕкАМЕННОУгОльН ОИ, гЕОсИНклИНАльНОИ ВУлкАНИЧЕскИ-ОсАДОЧ НОИ тОлЩЕ пОРОД. ДАН кРАткИИ РЕгИОНАл ьНО-гЕОлОгИЧЕскИИ ОБ жОР РУДНОИ пРОВИНцИИ, А тАкжЕ ОпИсыВАЕтсь гЕОлОгИ ь тРЁх шАхтНых пОлЕИ: л ОжАл (пОРтУгАлИь), лА-сАРсА И тАРсИс (пРОВИНцИь УЁл ьВА, ИспАНИь). пОДЧЁРкИ ВАЕтсь тЕсНАь сВьжь кОлЧЕДА НОВых И МАРгАНцЕВых ОРУДНЕ НИИ с кИслыМ, ЩЕлОЧНО-АкцЕНтИРОВА ННыМ пОДВОДНыМ ВУлкАНИжМОМ. ОБРАжОВАНИЕ кОлЧЕДА ННых МЕстОРОжДЕНИИ пРИпИсыВАЕтсь сОльФ АтАРНОИ ДЕьтЕльНОстИ ВО ВРЕМ ь И, пРЕИМУЩЕстВЕННО, к кОНцУ кИслых ВУлкАНИЧЕскИ х ЁФФУжИВНых ИжВЕРжЕН ИИ. сОстАВ РУД кРУпНых МЕстОРОжДЕНИИ НА ОгР АНИЧЕННОМ пРОстРАНстВЕ (лИНжОИ ДНыЕ жАлЕжИ, сОДЕРжАЩ ИЕ ДО 100 МлН. тОНН МАссИВНых кОлЧЕДАННых РУД) ОБЩь сНьУт НАМыВОМ сУльФИ ДНых ИлОВ И ДЕтРИтОВых сУльФИДО В (Иж РАНьшЕ ОБРАжОВАНН ых МЕНьшИх жАлЕжЕИ) В к ОтлОВИНы, ВОжНИкАУЩИЕ НА-НОВО ВУлкАНОтЕктОНИЧЕск И пРИ пОстОьННО ИжМЕН ьУЩЕИсь тОпОгРАФИИ МОРскОгО ДНА. тАкУУ тОЧкУ жРЕНИь ОБ ОсНОВыВАУт ОсАДОЧНы М ОтлОжЕНИЕМ ЁтИх жАлЕжЕИ И слОИстОИ ВНУтРЕННЕИ стРУктУРОИ РУДНых тЕ л.The Spanish-Portuguese Pyrite Belt covers a large area in the SW part of the Iberian Peninsula from Seville to the westcoast of Portugal. Total reserves of aprox. 1.000 million tons of massive sulphide ores have an average content of 46% S, 42% Fe, and 2–4% Cu+Pb+Zn. The stratiform sulphide deposits and accompanying manganese mineralizations are of synsedimentary-exhalative origin. They occur in a Lower Carboniferous, geosynclinal, volcanic-sedimentary rock sequence, strongly folded during the Hercynian Orogeny. A brief outline of the regional geology of this ore province is given, and the geology of three mining districts is described: Lousal (Portugal), La Zarza and Tharsis (Huelva Province, Spain). A close relationship between sulphide and manganese ores with the submarine, acid alkaline volcanism is emphasized. Solfataric activity is responsible for the formation of sulphides in the final stages of volcanic extrusions. The ore concentration in big deposits (ore-lenses with up to 100 million tons of massive sulphides) has been due to inflows of sulphide muds and/or detrital sulphides into newly formed depressions of a contineously changing seafloor topography due to volcano tectonic movements.ZusammenfassungDer spanisch-portugiesische Kiesgürtel erstreckt sich im SW der Iberischen Halbinsel von Sevilla bis fast zur Westküste Portugals. Er birgt etwa 1 Mrd. Tonnen massiver Kieserze mit ca. 46% S, 42% Fe und 2–4% Cu+Pb+Zn. Die schichtigen Kieslagerstätten und die sie begleitenden Manganvorkommen sind synsedimentär-exhalativer Entstehung und kommen in einer herzynisch gefalteten, unterkarbonischen, geosynklinalen vulkanisch-sedimentären Gesteinsfolge vor. Es wird ein kurzer regionalgeologischer Abriß der Erzprovinz gegeben, und die Geologie der drei Grubenfelder Lousal (Portugal), La Zarza und Tharsis (Provinz Huelva, Spanien) wird beschrieben. Die enge Verknüpfung der Kies- und Manganvererzungen mit dem saueren, alkalibetonten untermeerischen Vulkanismus wird betont. Die Kieslagerstättenbildung wird der Solfatarentätigkeit während und vorwiegend gegen Ende der saueren, vulkanischen Effusionen zugeschrieben. Erzkonzentrationen großer Lagerstätten auf engstem Raum (linsenförmige Lager mit bis zu 100 Mio t massiver Kieserze) erklären sich durch Einschwemmen von Sulphidschlämmen und/oder detrischer Sulphide (aus vorher gebildeten kleineren Lagern) in neu entstandene Bekken einer sich vulkanotektonisch dauernd verändernden Topographie des Meeresbodens. Diese Deutung wird durch sedimentäre Erzstrukturen und schichtige, geochemische Internstrukturen der Erzlager untermauert. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 7
    Publication Date: 1974-01-01
    Description: кРАткОЕ сОДЕРжАНИЕОпИсАНы ЁФФЕкты ДВУх ФАж ДЕФОРМАцИИ В МЕлО ВОИ пОРОДЕ АльпИИскОИ ОРОгЕНЕт ИЧЕскОИ жОНы НА УгО-ВОстОкЕ тУ РцИИ. Их МОжНО РАссМАт РИВАть ВМЕстЕ с УжЕ ИжВЕстНыМИ ФАжАМ И ДЕФОРМАцИИ ВЕРхНЕМ ЕлОВОгО И тРЕтИЧНОгО пЕРИОДОВ В пРЕДгОРНОИ склАДЧАт ОИ жОНЕ НА УгЕ. пОДРОБН О РАссМОтРЕНА стРАтИг РАФИь ЁтОгО РАИОНА; ВпЕРВыЕ ОпИсА НО ОБРАжОВАНИЕ ОлИгО цЕНОВых пОРОД. ОтлОжЕНИь ВЕРх НЕМЕлОВОгО пЕРИОДА сОстОьт БОль шЕИ ЧАстьУ Иж МОРскИх кАРБОНАтОВ, НО ОНИ сОДЕРжАт ОДНУ кРАсНУУ ФОРМАцИ У. В НИжНИх слОьх кАРБО НАтА лЕжИт пРОслОИкА ОсНОВНОИ ВУлкАНИЧЕс кОИ пОРОДы. жНАЧИтЕль НОЕ стРАтИгРАФИЧЕскО НЕ сОглАсНОЕ жАлЕгАНИЕ ВыжВАНО пО ДНьтИЕМ, слЕДОВАВшИМ жА пЕРВОИ ФАжОИ ДЕФОРМАцИИ, пРИ кОтОРОИ ОБРАжОВАлИс ь пОгРУжАУЩИЕсь В сЕВ ЕРО-жАпАДНОМ НАпРАВлЕНИИ склАДкИ И сВьжАННыЕ с НИМИ НАД ВИгИ. ЁтИ склАДкИ ОтЧА стИ жАНОВО пРЕОБРАжОВАНы БОлЕЕ МОлОДыМИ, пРОстИРАУЩ ИМИсь В ВОстОЧНО-сЕВЕРО-ВОст ОЧНОМ НАпРАВлЕНИИ ск лАДкАМИ АльпИИскОгО ВОжРАст А И НАДВИгАМИ, кОтОРыЕ сУЩЕстВЕННО ИжМЕНИл И Их ОБлИк.The effects of two phases of deformation in Cretaceous rocks of the Alpine Orogenic Zone of south-eastern Turkey are described. These can be correlated with the late Cretaceous and Tertiary phases of deformation already known from the zone of foreland folding to the south. Some details of the stratigraphical succession are given and a previously unrecorded development of Oligocene rocks is described. The upper Cretaceous sediments are dominantly marine carbonates but include a red bed formation. Basic volcanics are intercalated with the lower carbonate beds. A profound unconformity separates the Eocene from the Upper Cretaceous. This unconformity results from uplift consequent upon the first phase of deformation which produced north-westward plunging folds and related thrusts. Some of these north-westerly folds have been considerably modified by the superposition of younger east-north-easterly trending Alpine folds and thrusts.ZusammenfassungDie Effekte zweier Verformungsphasen im Kreidegestein der alpidischen orogenetischen Zone im Südosten der Türkei werden beschrieben. Diese können mit den schon bekannten Verformungsphasen der Oberkreide und des Tertiärs in der Vorlandfaltungszone im Süden zusammen betrachtet werden. Einzelheiten über die Stratigraphie werden angegeben, und die Ausbildung oligozäner Gesteine wird zum ersten Mal beschrieben. Die Sedimente der Oberkreide bestehen zum größten Teil aus marinen Karbonaten, enthalten aber eine rote Formation. In den unteren Karbonatschichten ist basisches vulkanisches Gestein zwischengelagert. Eine erhebliche stratigraphische Diskordanz stammt aus einer Hebung, die der ersten Verformungsphase folgte, in der nach Nordwesten abtauchende Falten und verwandte Aufschiebungen entstanden. Diese Falten sind zum Teil überprägt von jüngeren ostnordöstlich streichenden alpidischen Falten und Aufschiebungen, die sie wesentlich veränderten.RésuméLes auteurs décrivent les effets des deux phases de déformation des roches crétaciques de la zone orogénique alpine du sud-est de la Turquie. On peut les mettre en corrélation avec les phases de déformation, déjà connues, du Crétacique supérieur et du Tertiaire dans la zone de plissement de l'avant-pays au sud. Les auteurs donnent quelques détails sur la succession stratigraphique et décrit pour la première fois le développement des roches oligocènes. Les sédiments du Crétacique supérieur sont surtout des carbonates marins, mais comprennent toutefois une formation rouge. Des roches volcaniques basiques sont intercalées dans les couches carbonatées inférieures. Une discordance nette sépare l'Eocène du Crétacique supérieur; elle résulte du soulèvement succédant à la première phase de déformation qui produisit les plis plongeant au nord-ouest et les chevauchements apparentés. Ces plis ont été en partie remaniés par des plis et des chevauchements alpins plus jeunes, de direction est-nord-est, qui les ont fortement modifiés. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 8
    Publication Date: 1974-01-01
    Description: кРАткОЕ сОДЕРжАНИЕВ тЕЧЕНИЕ ДОлгОгО ВРЕ МЕНИ ВОжРАст пОслЕДН ЕгО МЕтАМОРФИжМА жОНы сЕ жИь пРИНИМАлИ жА гЕРцИНс кИИ, ИлИ ДАжЕ БОлЕЕ ДРЕ ВНИИ. В кАЧЕстВЕ АРгУМЕНтА слУжИлИ ВклУЧЕНИь ФУ НДАМЕНтА В тРАхИАНДЕ жИтАх И АНДЕжИтАх жОНы сЕжИь. пО АНАлОгИИ с пЕРМскИМИ ВУлкАНИтАМИ УжНых Ал ьп ЁтИ ВУлкАНИты пРИНИМАлИ жА пОРОДы пЕРМскОгО ВОж РАстА. В пОслЕДНЕЕ ВРЕ Мь БылИ НАИДЕНы В тИФФИтАх ВУ лкАНИтОВ сЕжИИ ОстАткИ РАстЕН ИИ, кОтОРыЕ ОтНЕслИ к В ЕРхНЕМУ кАМЕННОУгОльНОМУ пЕРИОДУ. НО ОкАжАлОсь, ЧтО ЁтИ ВыВОДы стОьлИ В пРОтИВОРЕЧИИ сО к стРУктУРНОгЕОлОгИЧ ЕскИМ НАБлУДЕНИьМ И МНОгОЧИслЕННыМ РАДИ ОМЕтРИЧЕскИМ ОпРЕДЕлЕНИьМ ВОжРАс тА В жОНЕ сЕжИь И ЁтО жА стАВИлО пРИстУпИть к пРОВЕРк Е пАлЕОБОтАНИЧЕскИх Д АННых. НАИДЕННАь НАМИ ФлОРА ОБНАРУжИлА сОВРЕМЕН НыЕ ЧЕРты И ЕЁ МОжНО пРИЧИ слИть к тРЕтИЧНОМУ пЕ РИОДУ. НЕ БылА НАИДЕНА НИ ОДНА пАлЕОжОИскАь ОкАМЕН ЕлОсть. пОДтВЕРжДЁНН ыИ ОстАткАМИ РАстЕНИИ тРЕтИЧНыИ ВОжРАст ВУлкАНИтОВ М ОжНО БылО УтОЧНИть пО сРЕДстВОМ РАДИОМЕтРИЧЕскИх ОпРЕДЕлЕНИИ ВОжРАст А пО к-Аг-МЕтОДУ В 29—33 МлН. лЕт. пОслЕДНИИ МЕтАМОРФИ жМ ВысОкОгО ДАВлЕНИь В ж ОНЕ сЕжИь ИМЕл МЕстО, к Ак пОкАжАлО ОпРЕДЕлЕНИ Е ЕгО НА слУДАх пО МЕтОД У к-Аг — МЕжДУ 60 И 90 МлН. лЕт. РАспОлОжЕННыЕ пО НАпРАВлЕНИУ к АльпАМ пАРтИИ жОНы сЕжИь Был И жАНОВО пРЕОБРАжОВАНы лЕпОН тИНскОИ кРИстАллИжАцИОННОИ ФАжОИ В жЕлЕНОслАНцЕ ВыИ ФАцИИ.For a long time the age of the last metamorphism of the Sesia-zone was considered to be Hercynian or older. Basement inclusions in basic volcanics were the main argument for this interpretation. The Trachyandesites — Andesites of the Sesia-zone were regarded as Permian, analogoues to the widespread Permian volcanics of the Southern Alps. Recently, plant remnants have been found in tuffitic interlayers of the Sesia volcanics. These fossils have been described as palaeozoic plants, in contradiction to structual observations and to the numerous radiometric data acquired in the region. To check the age of the fossils a detailed palaeobotanical study was carried out. Our samples contained a very modern flora of definitely Tertiary age. Not one palaeozoic fossil was detected. The Tertiary age found on palaeobotanical evidence proved to be between 29 and 33 m. y. on the basis of total rock K-Ar ages. The last high pressure metamorphism of the Sesia-zone occurred between 90 and 60 m. y. as has been shown by radiometric ages on micas. The external part of the zone was overprinted by the Lepontine phase of metamorphism in greenschist facies 38 m. y. ago.RésuméL'âge du dernier métamorphisme de la zone de Sesia a été pendant longtemps considéré comme hercynien ou plus ancien. Le principal argument à l'appui de cette interprétation consistait dans la présence d'inclusions cristallines du socle dans les trachyandésites et andésites situées dans la bordure interne de la zone de Sesia, ces roches volcaniques étant regardées comme permiennes par analogie avec le volcanisme permien des Alpes méridionales. On a trouvé récemment, dans les tuffites intercalées dans ces roches volcaniques, des fossiles végétaux qui ont été attribués au Carbonifère supérieur. Toutefois cette interprétation s'opposait aux observations structurales et aux nombreux âges radiométriques obtenus dans la zone de Sesia, ce qui a conduit, à une vérification détaillée des arguments paléobotaniques. La flore que nous avons trouvée est une flore très récente, d'âge tertiaire indubitable. On n'a pas trouvé un seul fossile paléozoÏque. Cet âge tertiaire basé sur la paléobotanique a été précisé par des mesures d'âge K-Ar effectuées sur roches totales, qui ont donné 29–33 m. a. La dernière phase métamorphique de haute pression, dans la zone de Sesia-Lanzo, a eu lieu entre 60 et 90 m. a., comme le montrent les âges radiométriques de micas. La partie de cette zone, proche des Alpes, a été soumise ultérieurement à la phase de métamorphisme lépontienne, qui s'est déroulée, il y a 38 m. a., dans un faciès de schistes verts.ZusammenfassungDas Alter der letzten Metamorphose der Sesia-Zone wurde lange Zeit für herzynisch oder älter gehalten. Als Argument dienten Grundgebirgseinschlüsse in den Trachyandesiten bis Andesiten der Sesia-Zone. Diese Vulkanite hielt man in Analogie zu den permischen Vulkaniten der Südalpen für permisch. In jüngster Zeit wurden in Tuffiten der Sesia-Vulkanite Pflanzenreste gefunden, die als oberkarbonisch beschrieben wurden. Diese Schlüsse standen in Diskrepanz zu strukturgeologischen Beobachtungen und zu den zahlreichen radiometrischen Altersbestimmungen in der Sesia-Zone und zwangen zur nochmaligen überprüfung der paläobotanischen Evidenzen. Die von uns gefundene Flora weist sehr moderne Züge auf und läßt sich mit Sicherheit ins Tertiär einstufen. Kein einziges paläozoisches Fossil wurde gefunden. Das durch die Pflanzenreste bestätigte tertiäre Alter der Vulkanite konnte mit radiometrischen K-Ar-Gesamtgesteinsaltern auf 29–33 m.y. präzisiert werden. Die letzte Hochdruck-Metamorphose in der Sesia-Zone fand nach K-Ar-Altersbestimmungen an Glimmern zwischen 60 und 90 m. y. statt. Vor ca. 38 m. y. wurden die alpeneinwärts liegenden Partien der Sesia-Zone von der lepontinischen Kristallisationsphase in Grünschieferfazies überprägt.RiassuntoDa molto tempo si riteneva che il metamorfismo di alta pressione e bassa temperatura della Zona Sesia-Lanzo fosse ercinico o più antico. Questa interpretazione cronologica si basava sulla presenza di rocce cristalline del basamento in vulcaniti basiche non metamorfiche situate, nel Biellese, al margine interno della Zona Sesia-Lanzo e sull' ipotesi che queste ultime fossero permiane per analogia con le vulcaniti delle Alpi meridionali. In questo complesso sono stati recentemente rinvenuti livelli detritici con resti vegetali attribuiti al Paleozoico. Questa interpretazione cronologica contrasta con osservazioni geologico-strutturali e con numerose datazioni radiometriche. Abbiamo quindi riesaminato la situazione. Nelle rocce in questione abbiamo rinvenuto una flora molto recente, di sicura età terziaria; mancano invece fossili paleozoici. L'età terziaria del complesso vulcano-detritico del Biellese è comprovata da datazioni radiometriche: le andesiti hanno età roccia totale K-Ar comprese tra 29 e 33 m. a. Le età radiometriche della mica bianca negli scisti cristallini della Zona Sesia-Lanzo indicano che il metamorfismo di alta pressione e bassa temperatura si è sviluppato tra 90 e 60 m. y. Ad esso si sovrappone successivamente la fase metamorfica lepontina di 38 m. a., diffusa nel settore esterno della Zona Sesia-Lanzo. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 9
    Publication Date: 1974-01-01
    Description: Das Nebengestein der Mitterberger Kupfererzlagerstätte wird in zwei Einheiten untergliedert: die Violette Serie im Hangenden und die Pinzgauer Phyllitzone im Liegenden. Es wird der epigenetische Charakter der Vererzung innerhalb der Violetten Serie bestätigt. Aus der liegenden Phyllitzone wird ein schichtförmiger Erzbestand beschrieben, der ca. 4 km westlich Mitterberg auftritt. Dieser primäre Erzbestand und die in Mitterberg selbst beobachteten Reliktstrukturen sprechen für eine Entstehung der gangförmigen Vererzung in der Violetten Serie als Folge einer partiellen Remobilisation.кРАткОЕ сОДЕРжАНИЕВМЕЩАУЩАь пОРОДА МИт тЕНБЕРгскОгО МЕДНО-Р УДНОгО МЕстОРОжДЕНИь пОДРА жДЕльУт НА ДВЕ стРАтИгРАФИЧЕ скИЕ ЕДИНИцы: ФИОлЕтО ВАь сЕРИь В кРОВлЕ И пИНцгАУскАь ФИллИтОВАь жОНА В пОД ОшВЕ. ЁпИгЕНЕтИЧЕскИ И хАРАктЕР ОРУДНЕНИь В пРЕДЕлАх ФИОлЕтОВОИ сЕРИИ ДОкАжАН. В пОДст ИлАУЩЕИ ФИллИтОВОИ жОНЕ ОпИс АНы слОИ РУДНых ОтлОжЕНИ И, ВстРЕЧАУЩИЕсь пРИБ лИжИтЕльНО 4 кМ жАпАДНЕЕ От МИттЕРБЕРгА. ЁтИ пЕРВ ИЧНыЕ ОтлОжЕНИь РУДы И НАБлУДАЕМыЕ В сАМОМ М ИттЕРБЕРгЕ РЕлИктОВыЕ стРУктУР ы сВИДЕтЕльстВУУт ОБ ОБРАжОВАНИИ жИлОпОДОБНОгО ОРУДНЕНИь В ФИОлЕтОВ ОИ сЕРИИ В РЕжУльтАтЕ ЧАстИЧНОИ пОВтОРНОИ МОБИлИжАц ИИ.RésuméLe roches encaissantes du gisement cuprifère de Mitterberg/Autriche sont divisées en deux ensembles: la Série Violette au toit et la Zone des Phyllites de Pinzgau au mur. Le caractére épigénétique de la minéralisation dans la Série Violette est établi. Un échantillon de minerai stratiforme, provenant de la Zone de Phyllite de Pinzgau, à environ 4 km à l'ouest de Mitterberg, est décrit. Ce minerai primaire et les structures résiduelles observées à Mitterberg lui-mÊme indiquent pour le gÎte filonnien dans la Série Violette une génèse due à une remobilisation partielle.The country rocks occurring with the copper ore-deposit at Mitterberg/Austria have been divided into two different units: the Violet Series and the underlying Pinzgau Phyllite Zone. The epigenetic character of the ore within the Violet Series has been confirmed. Within the Pinzgau Phyllite Zone a stratabound ore band, which occurs about 4 km west of Mitterberg, has been described. The primary nature of this ore band, together with the observations of relict fabrics from Mitterberg itself, support the author's explanation that the vein-type deposits in the Violet Series are a result of a partial remobilisation. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 10
    Publication Date: 1974-01-01
    Description: The southern Norwegian molybdenum deposits have hitherto been looked upon as typical examples of deposits of pneumatolytic — catathermal origin formed by emanations from intrusive granites. It is now demonstrated that all these deposits are to be found stratabound in a series of grey gneisses. They are accompanied by varying amounts of graphite and apatite of biogenetic origin and all of them show the same sulphide and oxide ore mineral paragenesis. It is concluded that the concentration and precipitation of metals took place in marine environments. Both the ores and their host rocks later underwent the same highmetamorphic processes.ZusammenfassungDie südnorwegischen Molybdänitvorkommen, einschließlich der bekannten Knabengruben, wurden bisher als pneumatolytisch-katathermale Bildungen im Verband mit intrudierten Graniten gedeutet. Es wird jedoch aufgezeigt, daß alle Vorkommen schichtgebunden in einer grauen Gneisserie liegen und zusammen mit biogenen Graphit- und Apatitgehalten gleiche sulfidische und oxydische Mineralparagenesen führen. Es wird gefolgert, daß aufgrund der geologischen, tektonischen und mineralogischen Befunde eine Konzentration und Ausfällung der Metalle im marinen Milieu mit nachfolgender hochmetamorphen überprägung des Mineralbestandes als Bildungsvorgang anzunehmen ist.кРАткОЕ сОДЕРжАНИЕУжНОНОРВЕжскИЕ МЕст ОРОжДЕНИь МОлИБДЕНА, ДО ИжВЕсткОВых шАхт „кН АБЕНгРУБЕН“ ВклУЧИтЕльНО, ИстОлк ОВыВАлИ ДО сИх пОР, кАк пНЕВМАтОлИтО-кАтАтЕ РМАльНыЕ ОБРАжОВАНИь, сВьжАНН ыЕ с ИНтРУжИьМИ гРАНИ тА. ОДНАкО, ВыьВлЕНО, ЧтО ВсЕ МЕстОРОжДЕНИь жА лЕгАУт пОслОИНО В сЕР ОИ сЕРИИ гНЕИсОВ, И ЧтО ОНИ сОДЕРжАт, НАРьДУ с БИО гЕННыМИ гРАФИтОМ И Ап АтИтОМ, тАкжЕ сУльФИДНыЕ И ОкИслЕННыЕ пАРАгЕНЕ жИсы МИНЕРАлОВ. ИсхОД ь Иж гЕОлОгИЧЕскИх, тЕктО НИЧЕскИх И МИНЕРАлОгИЧЕскИх Д АННых, ДЕлАУт ВыВОД, Чт О пРОцЕсс ОБРАжОВАНИь шЕл жДЕс ь пУтЕМ НАкОплЕНИь И Ос АжДЕНИь МЕтАллОВ В МО РскОИ сРЕДЕ с пОслЕДУУЩИМИ ВысОкОМЕтАМОРФИЧЕс кИМИ пРЕОБРАжОВАНИь МИ МИНЕРАлОгИЧЕскОгО с ОстАВА.RésuméLes gisements métallifères de molybdene de la Norvège du Sud ont jusque a maintenant étaient regardé des examples typiques d'origine pneumatolytique — catathermal originées par des émanations des granites intrusives. Maintenant c'est demonstré que toutes les gisements sont trouvés stratiforms dans une série de gneisses grises. Ils sont accompagnées par des quantités variés de graphite et d'apatite d'origine biogène, et que tous montrent la meme paragenèse des minéraux Sulfides aussi que oxides. On a conclu que la concentration et la précipitation des metaux auraient lieu dans les environs marins. Les gisements métallifères et leur roches succombaient des processes identiques de metamorphose. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 11
    Publication Date: 1974-01-01
    Description: Dans les séries volcano-sédimentaires du Paléozoique ancien, il existe un type de gisement à scheelite, lié à une certaine époque et de répartition mondiale. Cette observation soulève le problème d'une succession réglée des types de gisements, en relation avec l'évolution de l'écorce terrestre et du manteau. Dans le modèle proposé, l'évolution débuterait avec une écorce primitive, encore mince, puis se continuerait par des stades spécifiques, tels ceux à ceintures de roches vertes et à zones mobiles. Ces stades seraient acompagnés, grâce à un volcanisme juvénile, d'un abondant apport de matière correspondant à des minéralisations spécifiques d'époque. Elle aboutit, à partir du bouleversement assyntique, à une écorce «autarcique», qui se transforme essentiellement par un magmatisme palingène. Au cours de la période «juvénile», comme pendant la période «palingène», les processus sédimentaires participent au transport, à la remobilisation et à la reconcentration de matières. Ces processus sont liés de manière univoque à l'évolution de l'atmosphère et de la biosphère dont ils caractérisent les différents moments. Pendant le stade «palingène», l'écorce ne reÇoit qu'épisodiquement de la matière provenant du manteau, grâce à des lignes volcaniques d'importance mondiale. C'est ainsi que des types de gisement nouveaux, tels que les minerais à scheelite du Paléozoique ancien, ou les minerais à cuivre-molybdène de la limite MésozoÏque-CénozoÏque, peuvent apparaÎte à ces occasions avec leur spécificité d'époque.Proceeding from the observation that in the Early Paleozoic there is a time-bound, world-wide distributed ore deposit type with scheelite in volcanic-sedimentary series, the question concerning a systematic development of ore deposits connected with an evolution of the earth's crust and mantle is discussed. A schematic model of this development is constructed, which, beginning with a still thin, primeval crust, by way of time-bound stages as for instance greenstone belts and mobile zones, receiving abundant material introduction from juvenile volcanism accompanied with corresponding time-bound ores, leads to the “Assynthic” revolution, giving rise to a crust which is essentially dependent on selfsupport by sedimentary reworking and palingenic magmatism. During the initial “juvenile” period as well as during the palingenic there is significant participation of sedimentary processes, in dependence upon time-bound evolution of the atmosphere and biosphere, for material transport, redeposition and renewed concentration. During the “palingenic” stage the crust is only episodically supplied with mantle material along world-wide volcanic, tectonic lineaments, whereby new ore types, for example the scheelite ores of the Early Paleozoic or the copper-molybdenum ores at the Mesozoic-Cenozoic transition, experience their time-bound formation.кРАткОЕ сОДЕРжАНИЕИсхОДь Иж НАБлУДЕНИь, ЧтО В НИжНЕпАлЕОжОИс кОИ ЁРЕ ИМЕЕтсь тИп РУДНых МЕстОРОжДЕНИИ с шЕЕл ИтОМ В ВУлкАНО-ОсАДОЧ Ных сЕРИьх, ОБУслОВлЕННыИ ВРЕМЕ НЕМ И РАспРОстРАНЁННыИ п О ВсЕМУ жЕМНОМУ шАРУ, О БсУжДАУт ВОпРОс ОБРАжОВАНИь РУДНых МЕстОРОжДЕНИ И И Их сВьжИ с ЁВОлУцИЕ И жЕМНОИ кОРы И МАНтИИДАЕтсь МОДЕльНАь схЕМА РАжВ ИтИь, кОтОРОЕ пРИВОДИ т, НАЧИНАь От ЕЩЁ тОНкОИ, пРИМИтИВНОИ кОРы, ЧЕР Еж ОБУслОВлЕННыЕ ВРЕ МЕНЕМ стАДИИ (кАк-тО жЕлЁНОк АМЕНыЕ пОьсА И пОДВИжНыЕ жОН ы) ОБИльНОгО пРИНОсА М АтЕРИАлА жА сЧЁт УВЕНИльНОгО ВУлкАНИжМА, ЧтО сОпРО ВОжДАлОсь пОьВлЕНИЕ М сООтВЕтстВУУЩИх, ОБУ слОВлЕННых ЁтОИ ЁпОхОИ, РУД, ДО „Ас сИНтИИскОгО“ пЕРЕлО МА, кОгДА кОРА, пО сУЩЕстьУ, жАВИсИлА От сАМОсНАБ жЕНИь пАлИНгЕННыМ МА гМАтИжМОМ. кАк В пЕРВОМ, „УЕНИльН ОМ“, пЕРИОДЕ, тАк И ВО ВтОРО М, „пАлИНгЕННОМ“ пРОц Ессы ОсАДкОНАкОлДЕНИь (стОьЩИЕ ВО ВРЕМЕННОИ жАВИсИМОстИ От РАжВИ тИь АтМОсФЕРы И БИОсФЕРы) пРИНИМАУт УЧАстИЕ В т РАНспОРтЕ ВЕЩЕстВА, пЕРЕгРУппИРОВкЕ ВЕЩ ЕстВА И НОВОИкОНцЕНт РАцИИ ВЕЩЕстВА. В „пАлИНгЕН НОИ“ стАДИИ ВУлкАНИЧ ЕскИЕ пРОцЕссы пОДВОДьт кОРЕ МАНтИИ НыИ МАтЕРИАл пО шИРОк О РАспРОстРАНЕННыМ тЕ ктОНИЧЕскИМ тРЕЩИНАМ тОлькО лИшь ЁпИжОДИЧЕскИ, пРИЧЁМ НОВыЕ тИпы РУД — кАк НАпР., шЕЕлИтОВыЕ РУДы В НИж НЕпАлЕОжОИскОИ ЁРЕ, И лИ МЕДНО-МОлИБДЕНОВыЕ Р УДы НА РУБЕжЕ МЕжОжОь-кАИНО жОь — пРОьВльУт спЕцИ ФИЧЕскИЕ ОБУслОВлЕННыЕ ЁпОхО И ЧЕРты ФОРМИРОВАНИь.ZusammenfassungAusgehend von der Beobachtung, daß es im Altpaläozoikum einen zeitgebundenen, weltweit verbreiteten Lagerstättentyp mit Scheelit in vulkano-sedimentären Serien gibt, wird die Frage einer gerichteten Entwicklung der Erzlagerstätten im Zusammenhang mit einer Evolution von Erdkruste und Erdmantel diskutiert. Es wird ein Modellschema für die Entwicklung aufgestellt, die beginnend mit einer noch dünnen, primitiven Kruste über zeitgebundene Stadien, wie Grünsteingürtel und mobile Zonen, mit reichlicher Stoffzufuhr durch juvenilen Vulkanismus begleitet von den entsprechenden zeitgebundenen Erzen bis zum „assynthischen“ Umbruch mit einer Kruste führt, die im wesentlichen auf Selbstversorgung mit palingenem Magmatismus angewiesen ist. Sowohl im ersten „juvenilen“ wie im zweiten „palingenen“ Abschnitt sind sedimentäre Vorgänge in zeitgebundener Abhängigkeit von der Entwicklung der Atmo- und Biosphäre an Stofftransport, Stoffumlagerung und Stoffneukonzentration beteiligt. Im „pailgenen“ Stadium wird der Kruste nur episodisch Mantelmaterial auf weltweiten tektonischen Linien vulkanisch zugeführt, wobei neue Erztypen, wie z. B. die Scheelitzerze im Altpaläozoikum oder die Kupfer-Molybdän-Erze, an der Wende Mesozoikum-Känozoikum ihre zeitgebundene Bildung erfahren. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 12
    Publication Date: 1974-01-01
    Description: кРАткОЕ сОДЕРжАНИЕсВИНцОВО-цИНкОВыЕ РУ ДНыЕ МЕстОРОжДЕНИь Д ОлИНы пФлЕРштАль ВстРЕЧАУ тсь В ВИДЕ пРОслОЕк В склА ДЧАтых (ДОтРИАсОВОЕ склАДкООБРАжОВАНИЕ) И В МЕтАМОРФИжИРОВАН Ных пЕсЧАНО-пЕлИтОВых От лОжЕНИьх ЁцтАльскО-ш тУБАИскОИ МАссы. РУДНыЕ ОтлОжЕНИь (В тО М ЧИслЕ цИНкОВАь ОБМА НкА сВИНцОВыИ БлЕск, МАгН ИтНыИ кОлЧЕДАН) ОБРАжУУт ст РАтИгРАФИЧЕскИ кОНт РОлИРУЕМыЕ гРАФИтОВыМИ слАНцАМ И И МЕтАтУФФИтАМИ жАлЕ жИ ВАРИИРУУЩЕИ МОЩНО стИ ДО НЕскОлькИх МЕтРОВ. В кАЧЕстВЕ пЕРВИЧНОИ с ОстАВНОИ ЧАстИ ОкРУж АУЩЕИ сЕРИИ МЕтАОсАДкОВ ОНИ пОДВ ЕРглИсь тОМУ жЕ сАМОМУ МЕтАМО РФИЧЕскОМУ пРЕОБРАж ОВАНИУ, кОтОРОЕ тРАНсФОРМИР ОВАлО ВМЕЩАУЩИЕ Их пОРОДы В тЕЧЕНИЕ НЕскОлькИх пЕтРОгЕНЕтИЧЕскИх п РОцЕссОВ. ОцЕНкА УслОВИИ ДАВлЕ НИь/тЕМпЕРАтУРы пОсл ЕДНЕгО ДО-тРИАсОВОгО МЕтАМО РФИжМА, А тАкжЕ МИкРОскОпИЧЕ скИЕ ДАННыЕ И пОлЕВыЕ НАБлУДЕНИь РАжРЕшАУт пРЕДпОлАгАть, ЧтО жДЕ сь жНАЧИтЕльНУУ РОль сИгРАлА МОБИлИжАцИь сУльФИД ОВ, ИДУЩАь пОРОИ ВплОть Д О РАсплАВлЕНИь ЁтИх п ОслЕДНИх. В НАстОьЩЕЕ ВРЕМь ЕЩЁ НЕльжь ДАть пОлОжИтЕ льНыИ ОтВЕт НА ВОпРОс О ДОпОлНИтЕльНОИ Альп ИИскОИ МОБИлИжАцИИ РУД. ОпРЕ ДЕлЕНИь ВОжРАстА И пЕтРОгЕНЕтИЧЕскИЕ И сслЕДОВАНИь пОРОД ЁцтАльскО-штУБ АИскОИ МАссы, пРОВЕДЕ НыЕ ДРУгИМИ АВтОРАМИ, ДОпУскАУт пРЕДпОлОжЕНИЕ О сИлУ РИИскОМ, Быть МОжЕт ДА жЕ ДО-сИлУРИИскОМ ВОжРА стЕ (410 МлН. лЕт) РУДОНОстНых МЕтАОсАДкОВ ДОлИНы п ФлЕРштАль.ZusammenfassungDie Blei-Zinkerzlagerstätten des Pflerschtals treten schichtgebunden in prätriadisch verfalteten und metamorphosierten sandig-pelitischen Sedimenten der ötztal-Stubaier-Masse auf. Die Erze (u. a. Zinkblende, Bleiglanz, Magnetkies) bilden stratigraphisch durch Graphitschiefer und Metatuffite kontrollierte Lager stark variierender Mächtigkeit bis zu einigen Metern. Als primärer Bestandteil der umgebenden Metasediment-Serie unterlagen sie der gleichen metamorphen überprägung, die das Nebengestein im Verlauf mehrerer petrogenetischer Akte umgeformt hat. Die Abschätzung der p-T-Bedingungen der letzten prätriadischen Metamorphose sowie mikroskopische und Geländebefunde führen zu der Annahme, daß in erheblichem Umfange Sulfidmobilisationen, teilweise vielleicht bis zur Sulfidaufschmelzung, eine Rolle gespielt haben. Die Frage nach einer möglich erscheinenden, zusätzlichen alpidischen Erzmobilisation ist zur Zeit noch nicht zu beantworten. Altersbestimmungen und petrogenetische Untersuchungen an Gesteinen der ötztal-Stubaier-Masse durch andere Autoren lassen ein silurisches, vielleicht sogar ein präsilurisches Alter (〉 410 my) der erzführenden Metasedimente des Pflerschtals vermuten.The stratabound lead zinc ore deposits of the Pflersch Valley (Eastern Alps) are intercalated in pre-Triassic folded and metamorphosed pelitic sediments of the ötztal-Stubaier Masse. The ores (sphalerite, galena, pyrrhotite etc.) are stratigraphically controled by graphitic shists and tuffitic layers. The thickness of the ore bodies varies between some centimeters to some meters. As part of the regional setting these orebearing strata were metamorphosed during several metamorphic episodes together with these metasediments. Field observations, supplimented by microscopic studies, and the calculation of p-T-conditions indicate that now partly mobilized ores probably had their origin during the last pre-Triassic metamorphic events. These ores probably came in part as sulfide melts. There seems also a possibility of an additional alpine ore mobilization process. On the basis of age determinations and petrographic studies carried out in the ötztal-Stubaier Masse by other authors it is possible to say that the ore-bearing former sediments belong to Silurian or even pre-Silurian age (〉410my).RésuméLes gisements de plomb et de zinc de la vallée du Pflersch sont liés au sédiments gréso-pélitiques du Massif de l'Oetztal et de Stubai (Alpes orientales). Ces sédiments ont subi des plissements et des métamorphismes prétriasiques. Les minerais (e. a. blende, galène, pyrrhotine) alternent avec des schistes à graphite et avec des métatuffites et accusent des épaisseurs variables allant jusqu'à quelques mètres. En tant que partie intégrante des séries sédimentaires encaissantes, ils ont subi les mÊmes modifications métamorphiques que celles-ci au cours de plusieurs phases pétrogénétiques. L'évaluation des conditions p-T du dernier métamorphisme prétriasique ainsi que les analyses microscopiques et sur le terrain conduisent à l'hypothèse d'une mobilisation importante et peut-Être mÊme d'une fusion partielle des sulfides. Pour le moment on ne peut pas se prononcer sur le bien-fondé d'une mobilisation métallifère additionnelle au cours de l'orogenèse alpine, mais celle-ci semble possible. Les datations et les analyses pétrologiques des roches du Massif de l'Oetztal et de Stubai suggèrent un âge silurien, peut-Être mÊme présilurien (〉 410 my) pour les méta-sédiments métallifères de la vallée du Pflersch. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 13
    Publication Date: 1974-12-01
    Description: After a comment on the stratigraphical classification and the subdivision of Permian strata, a review on their occurrences in Central and Western Europe including the Alps is given. Within this area, the strata can be summarized to a northern, a central, and a “Verrucano” province. The Autunian (Lower Rotliegend) has been typically developed in the central province where it is best preserved. It is characterized by many different sedimentation processes the most important of which are described. They lead to the conclusion that the sediment deposition mainly took place in fresh water lakes and through fluviatile transport. On the other hand, the deposition of the Saxonian (Upper Rotliegend) took place in a much drier climate. Finally, the differences between the two types of climate are described.Краткое содержаниеОписано стратиграфи ческое подразделени е нижней перми и дан краткий обзор ее распростран ения в средней и запад ной Европе включая Альпы. Эту область распростран ения можно подраздел ить на северную, центральну ю и провинцию « Verrucano». Из обзо ра следует, что отений ский ярус, т.е. нижние свиты нижней перми пр оявляют типичное раз витие в центральной провинц ии, где они и сохранились лучше всего. Об этом свидетельствуют инт енсивные процессы осадконако пления, нашедшие свое отражение в описании важнейших свит. Приходят к вывод у, что отложения этих с едиментов происходило, гл. обр., в пресноводных водоемах, а перенос ма териала осуществлялся реками. Осадконакопл ение в Саксонии, т.е. в в ерхних свитах нижней перми шло при более сухом кл имате. В заключении ав тор указывает на господс тво различных климатиче ских условий в эту эпо ху.ZusammenfassungNach einer Stellungnahme zur strati graphischen Ein- und Untergliederung des Rotliegenden wird eine Übersicht über seine Vorkommen in Mittel- und Westeuropa einschließlich der Alpen gegeben. Innerhalb dieses Raumes lassen sie sich in eine nördliche, zentrale und in die „Verrucano“-Provinz zusammenfassen. Aus diesem Überblick ergibt sich, daß das Autunien — Unterrotliegendes in der zentralen Provinz am typischsten entwickelt und noch am besten erhalten geblieben ist. Es zeichnet sich durch eine Fülle von Sedimentationsvorgängen aus, von denen die wichtigsten beschrieben werden. Sie lassen darauf schließen, daß sich der Absatz der Sedimente überwiegend in Süßwasserseen und über einen fluviatilen Transport vollzog. Dagegen erfolgte er im Saxonien = Oberrotliegenden unter einem weitaus trockeneren Klima, dessen Unterschiede zu jenen im Unterrotliegenden abschließend beschrieben werden.RésuméL'auteur exprime d'abord ses opinions sur la stratigraphie du « Rotliegendes », son classement et ses subdivisions. Ensuite il donne une vue d'ensemble des gisements du « Rotliegendes » dans l'Europe centrale et occidentale, y compris les Alpes. A l'intérieur de cette région on peut distinguer trois provinces: la province septentrionale, la province centrale et la province du « Verrucano ». De cette vue d'ensemble il résulte que l'« Autunien » = « Unterrotliegendes » a trouvé son évolution la plus typique dans la province centrale et qu'il s'y est le mieux conservé. Ce qui le caractérise c'est une quantité de processus de sédimentation; l'auteur en donne une description. Il en tire la conclusion que la sédimentation s'est produite surtout dans des lacs d'eau douce et par un transport fluvial. Au contraire, la sédimentation dans le « Saxonien » = « Oberrotliegendes » s'est produite dans un climat beaucoup plus sec. La description des différences entre les deux climats (du Unterrotliegendes et du Oberrotliegendes) termine l'exposé. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 14
    Publication Date: 1974-12-01
    Description: Die dargestellten Regressions- und Korrelationsrechnungen ermöglichen eine Beurteilung von Beobachtungsmerkmalen hinsichtlich ihrer gegenseitigen Abhängigkeit. Eine solche Untersuchung wurde am Beispiel authigener Quarze aus devonischen Massenkalken des ostrheinischen Schiefergebirges ausgeführt. Für die statistische Auswertung ist das Vorliegen von Normalverteilung der Kollektive zu überprüfen. Es wird ein Testverfahren aufgezeigt, das unter Verwendung des Zentralen Grenzwertsatzes auch die zweidimensionale Dichteverteilung nachweist. Die Probleme bei der Aufstellung empirischer Formeln werden erläutert, wobei nur auf linearer Korrelation basierende Ausgleichskurven erfaßt werden. Die von einer geforderten statistischen Sicherheit abhängigen Vertrauensbereiche der Interpolationskurven werden ermittelt. Etwaige statistisch gesicherte Unterschiede zwischen den Beobachtungskollektiven können mit einer verallgemeinerten Variationsanalyse nachgewiesen werden. Die numerische Auswertung und die graphische Darstellung von Beispielergebnissen erfolgt mit Hilfe eines Computers, Typ ICL 1907, über Programme der Symbolsprache ALGOL 60. Dadurch wird eine übersichtlichere Darstellung von Meßergebnissen, eine bessere Einsicht in statistische Zusammenhänge und eine effektivere Auswertung anfallender Daten ähnlicher Art möglich.RésuméLes analyses de regression et correlation décrites rendent possible une évaluation de caractères observés portant sur leur dépendance mutuelle. Une telle analyse a été exécutée sur des quartz authigènes de calcaires devoniens de la Schiefergebirge située à l'est du Rhin. Pour l'évaluation statistique il est nécessaire d'examiner la distribution normale des résultats de recherche trouvés. Une méthode d'investigation est présentée qui contrôle aussi la distribution bidimensionale de « Gauss » en utilisant le théorème limitrophe central. Les problèmes concernant l'équation empirique sont discutés, limités à des courbes basées sur la corrélation linéaire. Les domaines de confiance dépendant d'une sûreté statistique ont été calculés pour les lignes d'interpolation. Des différences éventuelles statistiques entre les échantillons de recherche peuvent être prouvées par une analyse de variations généralisées. L'évaluation numérique et l'exposition graphique des résultats d'investigation sont faites par un computeur du type ICL 1907 en langue symbolique ALGOL 60. Par cette méthode une présentation plus claire des résultats, des connexions statistiques et une évaluation plus effective de données similaires sont rendues possible.The represented correlation and regression analysis allows an evaluation of the mutual statistical dependence of random variables. As a numerical example, such investigations have been made on authigenic quartz from Devonian limestones of the Eastern Rhenish Schiefergebirge. For statistical evaluation it is necessary to check the normal distribution of test results. The applied method makes possible to control a twodimensional Gauß-distribution with the aid of the central limit theorem. The problems to find out empirical equations are discussed; this case is restricted to curves based on linear correlations. The confidence ranges depending on statistical probabilities are calculated for the curves of interpolation. Statistical differences of test samples are proved by a generalised variated analysis. The numerical evaluation and the plotting of the investigated samples have been performed by a computer, type ICL 1907, in ALGOL 60 symbol language. Thereby it is easy to survey representation of test results, statistical connections and efficient evaluation of similar data.Краткое содержаниеС помощью регрессион ных и корреляционных вычеслений был исследован кварц из девонского и звестника восточно-р ейнских сланцевых гор. Указыв ается что удалось вывести э мпирическую формулу, причем учитывали только кривую с линей ной корреляцией. Опре делили доверительный интер вал интерполяционной кр ивой, отвечающий треб ованиями статистической надежности. Цифровую обработку и графическое изображ ение результатов провели на компьютере типа ICL 1907 по п рограмме ALGOL 60. Это привело к наглядн ости результатов изм ерения и облегчило просмотр статистических взаи мосвязей между наблю даемыми и теоретическими хара ктеристиками ©1974 Ferdinand Enke Verlag Stuttgart
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  • 15
    Publication Date: 1974-12-01
    Description: Thin sandlayers embedded in mud of various depositional sedimentary environments are compared. From a study of their characteristics such as grading, internal structure, size, lateral decrease of grain size and form, conclusions can be drawn about the various sedimentary environments.Краткое содержаниеСравнили тонкие прос лойки песка, захороне нные в иловых отложениях, в различных районах о садконакопления. По р азличию характеристик, как-то тип текстуры слоев, ве личина, мощность и уме ньшение зернистости на флангах и по форме, сде лали выводы о среде от ложения.RésuméL'auteur compare les minces intercalations sableuses dans les boues, provenant de différents domaines sédimentaires. On peut dès lors en se basant sur différentes caractéristiques, comme le granoclassement, le type structural de la couche, la grandeur, la puissance, la diminution latérale de la granularité et la forme, émettre des conclusions sur le domaine où s'est effectué le dépôt.ZusammenfassungEs wurden dünne, im Schlick eingebettete Sandlagen aus verschiedenen Ablagerungsbereichen verglichen. Dabei können anhand unterschiedlicher Merkmale, wie Gradierung, Art des Schichtgefüges, Größe, Mächtigkeit, laterale Korngrößenabnahme und Form, Schlüsse auf die Ablagerungsbereiche gezogen werden. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 16
    Publication Date: 1974-12-01
    Description: Diese Arbeit bespricht die Gliederungen des Neogens in den verschiedenen Sedimentationsräumen der Paratethys und der Ägäis. Sie bringt eine kritische Erläuterung einiger Tabellen, die sich nach den in den letzten Jahren veröffentlichten Einteilungen richten. Ein vergleichendes Schema wird gegeben für das Neogen im ägäischen Raum und für die Stufen und Unterstufen des Neogens in Italien sowie in der zentralen und östlichen Paratethys.This note comments the classifications of the Neogene for the different regions belonging to the Paratethys and to the Aegeid. Several tables taking into account the eastern Neogene divisions published recently are discussed. A coinparative scheme is presented for the Neogene of the Aegean area and the stages or substages in Italy and in the central and eastern Paratethys.Краткое содержаниеОбсуждается расчлен ение неогена а различ ных районах осадконакопления Перететиса и Эгейско го моря. Приведены и кр итически рассмотрены некотор ые опубликованные за по следние годы схемы. Дл я сравнения приведено подразделение неоге на в районе Эгейского моря, Италии, а также центральной и восточной части ПаRésuméCette note commente les classifications du Néogène établies dans les diverses régions de la Paratéthys et de l'Egéide. Elle présente une mise au point de quelques tableaux (qui tiennent compte des divisions du Néogène oriental parues ces dernières années. Elle se termine par un schéma comparatif du Néogène dans le domaine égéen et des étages et sous-étages établis en Italie et dans la Paratéthys centrale et orientale. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 17
    Publication Date: 1974-07-01
    Description: L'assimilation d'évaporites et de saumures par le magma basaltique montant dans des zones à rifts continentaux conduirait à des phénomènes de magmatisme et métasomatisme alcalins. Les spilites représenteraient le pendant océanique des syénites alcalines. La remobilisation de matériel alcalin à partir d'évaporites et de saumures serait également responsable de la feldspathisation (l'albitisation alpine, par exemple). De plus, elle pourrait jouer un rôle important dans la production de roches à glaucophane. Il est particulièrement significatif que les gisements les plus anciens, connus à ce jour, d'évaporites, de syénites néphéliniques, et de « schistes » à glaucophane, datent tous du Précambrien supérieur (ou de l'Eocambrien). Ces roches semblent augmenter de fréquence avec la diminution d'âge, ce qui pourrait refléter une évolution dans la teneur en alcalis (sodium surtout) de l'eau de mer, correspondant, à son tour, à l'alcalinisation croissante de la croûte terrestre.The assimilation of evaporites and brines by basaltic magma in continental rifts may be responsible for alkaline magmatism and metasomatism. Spilites may be the oceanic counterpart of alkaline syenites. Remobilisation of alkaline material from evaporites and brines may also lead to feldspathisation and, moreover, it may be an essential factor in the production of glaucophane-bearing rocks. It is particularly significant that the oldest known occurrences of evaporites, nepheline syenites, and glaucophane “schists” are all of late Precambrian (-Eocambrian) age. These rocks appear to have become increasingly abundant with decreasing age, and this may reflect an evolution in the alkali (especially sodium) content of sea water, which in turn may correspond to progressive alkalinisation of the Earth's crust.Краткое содержаниеАссимиляция эвапори тов и соляных раствор ов базальтовой магмой в зонах континентальных риф тов может быть ответс твенна за появление щелочного магматизма и метасом атизма. Спилиты могут представлять собой о кеаническиc эквиваленты щелочны х сиенитов. Повторная мобилизация щелочного материала, идущего от эвапорито в и соляных растворов, может быть также ответственна и за появление полево го шпата (напр.: альпийс кая альбитизация). Кроме того, этот процесс мог играть важную роль пр и образовании глаукоф ановых пород. Особенно интер есно то, что самые древ ние известные на сегодня залежи овапоритов, нефелин-с иенитов и глаукофано вых сланцев принадлежат к верхне му докембрию, или оокемб рию. Количество этих п ород увеличивается с умен ьшением возраста. Такое взаим оотношение может отр ажать эволюцию содержания щелочей в морской вод е — явление, которое, в свою очередь, может соотве тствовать увеличивающейся щел очности земной коры.ZusammenfassungDie Assimilation von Evaporiten und Solen durch basaltisches Magma in Zonen von kontinentalen Rifts dürfte für alkalischen Magmatismus und Metasomatismus verantwortlich sein. Die Spilite könnten das ozeanische Äquivalent der Alkalisyenite darstellen. Die Remobilisierung von alkalischem Material, ausgehend von Evaporiten und Solen, wäre auch für die Feldspatisation (z. B. die alpine Albitisierung) verantwortlich. Außerdem könnte dieser Vorgang eine wichtige Rolle bei der Bildung von Glaukophangesteinen spielen. Es ist von besonderer Bedeutung, daß die ältesten heute bekannten Lagerstätten von Evaporiten, Nephelinsyeniten und Glaukophanschiefern dem oberen Präkambrium (bzw. dem Eokambrium) angehören. Diese Gesteine scheinen mit abnehmendem Alter in ihrer Häufigkeit zuzunehmen. Dies könnte eine Evolution im Alkaligehalt des Meerwassers widerspiegeln, eine Erscheinung, welche ihrerseits einer zunehmenden Alkalisierung der Erdkruste entsprechen könnte. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 18
    Publication Date: 1974-07-01
    Description: La IUGS a chargé sa Subcommission on the Systematics of Igneous Rocks de discuter classification et nomenclature des roches éruptives et de lui en présenter des suggestions. La Subcommission s'est occupée jusqu'ici des roches plutoniques. Le présent article contient un sommaire des recommendations auxquelles la Subcommission a consenti à sa réunion de Montréal, août 1972. Un rapport plus détaillé est en préparation.The IUGS Subcommission on the Systematics of Igneous Rocks has been formed in order to review classification and nomenclature of igneous rocks and to present proposals to IUGS. Up to the present, the Subcommission has been concerned with plutonic rocks. This paper presents a summary of the recommendations on plutonic rocks to which the Subcommission has agreed at its meeting of Montreal, August 1972. A report that will contain fuller treatment is in preparation.Краткое содержаниеIUGS создана подкоммиеои я по „Systematics of Igneous Rocks' длл проверк и классификации к поме рклатуры эруптипных пород. подкомиссия исследо вала сначала породы глуби н. Приведенный здесь к раткий вывод предложений от носительно плутонитов получил о добрение на заседани и ее н is Монреале (август 1972 г). Подробное описани е подготовляется к пе чати.ZusammenfassungDie IUGS hat eine Subcommission on the Systematics of Igneous Rocks gebildet mit dem Auftrag, Klassifikation und Nomenklatur der Eruptivgesteine zu überprüfen und ihr entsprechende Vorschläge vorzulegen. Die Subcommission hat sich zunächst mit Tiefengesteinen befaßt. Sie unterbreitet hier eine kurze Zusammenfassung der Empfehlungen für Plutonite, denen sie bei ihrer Sitzung in Montreal (August 1972) zugestimmt hat. Eine ausführlichere Darstellung ist in Vorbereitung. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 19
    Publication Date: 1974-07-01
    Description: Краткое содержаниеАссоциации талька и д истена определяют, к х арактерный парагенез минералов нового тина кристалл инового сланца, т. н. „б елого сланца“, установленн ого недавно по многих рай онах и частично имеющ его региональное распро странение. Опытами доказали, что этот парагенез говор ит о давлении свыше 10 килобар. Однако огран ичение этого параген еза породами, богатыми ма гнием и алюминием и бедными д вухвалентным железо м, кальцием и щелочами не разрешае т выделить его, как новы й тип метаморфизма. Та кой необычный состав пор од оказывается очень чу вствительным геобар ометром в интервалах давлений около 10 килобар, которого для пород иного, „нормаль ного“ состава, по всей вероя тности, остается — „некритич еским“.The association of talc with kyanite is defined to be the characteristic mineral assemblage of a new type of crystalline schist, named whiteschist, which has recently been found in several localities, partly even on a regional scale. Based on experimental evidence this assemblage appears at water pressures in excess of about 10 kilobars. Its compositional limitation to rocks rich in Mg and Al, but poor in Fe2+, Ca, and alkalies does not allow the introduction of a new facies of metamorphism. However these unusual rock compositions provide a sensitive geobarometer in the pressure range near 10 kb for which other more “normal” rock compositions do not seem to be critical.RésuméOn définit l'association du talc avec le disthène comme paragenèse minérale caracteristique d'un nouveau type de schiste crystallin, nommé schiste blanc, qu'on a trouvé récemment dans plusieurs localités, des fois même en distribution régionale. Des travaux experimentaux ont démontré que cette paragenèse apparaît aux pressions d'eau au-dessus de 10 kilobars à peu près. La limitation de cette paragenèse aux roches riches en Mg et Al, mais pauvres en Fe2+, Ca et en éléments alcalins ne permet pas l'introduction d'un facies nouveau de métamorphisme. Cependant ces compositions non usuelles des roches représentent un géobaromètre sensitif dans la région des pressions près de 10 kb, où il semble que d'autres compositions plus « normales » des rochcs ne donnent pas des indications critiques.ZusammenfassungDie Vergesellschaftung von Talk mit Disthen wird definiert als die charakteristische Mineralparagenese eines neuen Typs von Kristallinem Schiefer, genannt Weißschiefer, der neuerdings von mehreren Lokalitäten, zum Teil sogar in regionaler Verbreitung, bekannt wurde. Durch experimentelle Arbeiten ist erwiesen, daß diese Paragenese bei Wasserdrucken oberhalb von etwa 10 Kilobar auftritt. Die Beschränkung dieser Paragenese auf Gesteinszusammensetzungen, die reich an Mg und Al, aber arm an Fe2+, Ca und Alkalien sind, gestattet nicht die Einführung einer neuen Fazies der Metamorphose. Dennoch stellen diese ungewöhnlichen Gesteinszusammensetzungen ein empfindliches Geobarometer im Druckbereich um 10 kb dar, für den anscheinend andere, ‚'normalere“ Gesteinschemismen unkritisch sind. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 20
    Publication Date: 1974-12-01
    Description: In der Permo-Trias von Mitteleuropa werden insgesamt 8 Violette Horizonte (VH 0, VH 1, VH 2, VH 3, VH 4, VH 5, VH 6 und VH A) als fossile, autochthone Bodenkomplexe erkannt. Die Kriterien für eine Bodenbildung werden zusammengestellt. Die Bedeutung der Violetten Horizonte für paläoklimatische, paläogeographische und stratigraphische Aussagen wird dargelegt. Für die Grenzziehung Saxonien/Thurmgien, Unterer/Mittlerer Buntsandstein und Mittlerer/Oberer Buntsandstein werden für Teilbereiche Mitteleuropas neue Vorschläge unterbreitet. Ein Vergleich der Wirbeltierfaunen des Violetten Horizontes 5 im Schwarzwald mit den Schichten der Grenzbitumenzone im Tessin (Südschweiz) macht es wahrscheinlich, daß der Obere Buntsandstein in das Anis und tiefere Teile des Muschelkalkes in das Ladin der Tethysgliederung gestellt werden müssen.RésuméDans le Permo-Trias de l'Europe Centrale, huit Horizons Violets (VH 0, VH 1, VH 2, VH 3, VH 4, VH 5, VH 6 et VH A) sont reconnus comme des complexes de sols fossiles et autochthones. Les critères de formation de sol en sont énumérés. L'auteur expose la signification des Horizons Violets en temps que lémoignages paléoclimatiques, paléogéographiques et stratigraphiques. La détermination des limites Saxonien/ Thuringien, Grès Bigarré inférieur/moyen et Grès Bigarré moyen/supérieur, fait l'objet de propositions nouvelles pour des diverses régions de l'Europe Centrale. Une comparaison des faunes de vertébrés de l'Horizon Violet 5 dans la Forêt Noire et des couches de la zone-limite-bitumineuse (« Grenzbitumenzone ») dans le Tessin (Suisse méridionale) rend probable l'attribution du Grès Bigarré supérieur à l'Anisien, et de la partie inférieure du Muschelkalk au Ladinien de la subdivision téthysienne.Краткое содержаниеВ качестве ископаемы х автохтонных почвен ных комплексов в пермотр иасском периоде средней Евро пы выделяют 8 Фиолетов ых горизонтов (ФГ 0, ФГ 1, ФГ 2, ФГ 3, ФГ 4, ФГ 5, ФГ 6, Ф Г А). Приведен целый ряд критериев, которые разрешают ох арактеризовать почвообразовательн ые процессы в эту эпоху. Подчеркив ается значение Фиоле товых горизонтов при заклю чении о палеоклимате, палео геолографии и страти графии. В отдельных районах Средней Евро пы предлагается нова я схема проведения границ между отдельными яру сами, именно: саксонск ий ярус (тюрингский ярус, нижний) средний пестр ый песчаник и средний /верхней пестры песчаник. На основании сравнения фауны позвоночных Фи олетового горизонта 5 в Шварцвал ьде со слоями погранично й битумной зоны в Тесс ине, южная Швейцария, Верхний пестрый песч аник предложили отне сти к анизийскому ярусу, а з алегающие ниже свиты раковинно го известняка, после р асчления Тетиса, — к ладинскому ярусу.In the central European Permo-Triassic, eight Violet Horizons (VH 0, VH 1, VH 2, VH 3, VH 4, VH 5, VH 6, and VH A) are recognized as fossil autochthonous soil complexes. The criteria for soil formation and the significance of the Violet Horizons for paleoclimate, paleogeography, and stratigraphy are presented. New proposals are made for the drawing of the Saxonian to Thuringian, Lower to Middle Bunter, and Middle to Upper Bunter boundaries in areas of central Europe. Comparison of the vertebrate fauna of Violet Horizon 5 with the strata of the “Grenzbitumen-Zone” (boundary Bituminous Zone) in the Tessin region (southern Switzerland) indicates a probable correlation of the Upper Bunter with the Anisian and the lower parts of the Muschelkalk with the Ladinian of the Tethys classification. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 21
    Publication Date: 1974-12-01
    Description: In den pleistozänen Sedimenten der Mosel und einiger ihrer Nebenflüsse konnte bei der Untersuchung der Schwerminerale ein sehr hoher Opakanteil festgestellt werden. Aufgrund dieses Tatbestandes und der nur geringen Differenzierung im transparenten Schwermineralspektrum wurden Erzanschliffe hergestellt und die opaken Mineralphasen untersucht. Das Ergebnis war: der Anteil der opaken Schwerminerale der pleistozänen Moselsedimente (HöT-NT) läßt sich eindeutig von denen der Nebenflüsse unterscheiden, da bis zu 50 Korn% des Opakanteils der Moselsedimente Brauneisenooide (Herkunft: Luxemburgische Minetteformation) führen. Damit ist der Schlüssel zur eindeutigen Charakterisierung von Moselsedimenten und zur Lösung der Frage nach der Herkunft der weitverbreiteten Schotterfluren im Bereich der Wittlicher Senke gegeben. Die Untersuchung der Vorkommen lieferte neben den geomorphologischen Anhaltspunkten den Beweis, daß die Mosel bis in die Zeit zwischen OMT und UMT auch durch die Wittlicher Senke (= Wittlicher Talweite) geflossen ist und somit eine Stromspaltung der Mosel zwischen Schweich und Mülheim/Lieser bis zu dieser Zeit bestanden hat. Dadurch wird eine alte Vermutung von Grebe (1881) bestätigt. Zusätzlich konnte mit dieser Methode nachgewiesen werden, daß der in der Wittlicher und Trierer Talweite verbreitete Löß aus den Moselsedimenten ausgeweht wurde.In the Pleistocene sediments of the Mosel and some of their tributaries the investigation of the heavy minerals showed a high content of opaques. This fact and the small differences in the distribution of the transparent heavy minerals initiated our ore-mineralogical studies of the opaque heavy minerals. The findings resulted in an exact distinction of the sediments of the Mosel from those of their tributaries by typical Limonite oölites (50 grain % of the opaques) originating from the Minette-formation of Luxemburg. By using this technique it is possible to characterize sediments of the Mosel and to elucidate the origin of the widespread Pleistocene sediments of the Wittlicher Senke area. Aside from geomorphological arguments, the investigations of these sediments produced exact evidence that the Mosel took its course through the Wittlicher Senke (= Wittlicher Mosel-Valley) during the Pleistocene period until the interval of the Upper to Lower MT-times (= Obere und Untere Mittelterrasse). Therefore, the Mosel ran through two valleys (bifurcation) between Schweich and Mülheim/Lieser until the Upper MT-time which was postulated by Grebe (1881). In addition this method enabled us to verify the loess being river loess, blown out of the sediments of the Mosel.RésuméEn analysant les minéraux lourds des sédiments du pléistocène de la Moselle et de quelques autres de ses affluents, nous avons pu constater un très haut pourcentage de minéraux lourds opaques. A cause de ce fait et à cause des différences insignifiantes dans le spectre des minéraux lourds transparents, nous avons étudié les différentes phases des minéraux opaques. Voici le résultat: les minéraux lourds opaques des sédiments du pléistocène de la Moselle se distinguent clairement de ceux des affluents parce qu'ils contiennent — jusqu'à 50 grain % de la part opaque — des oolites de ferrite. (Origine: formation minette du Luxembourg). Il est ainsi possible de caractériser exactement les sédiments de la Moselle et d'éclairer l'origine des cailloux du pléistocène largement répandus dans la région de la Wittlicher Senke. En dehors de ces arguments géomorphologiques l'analyse de ces sédiments a fourni la preuve que — jusqu'à la période entre le niveau haut et le niveau bas de la terrasse moyenne — la Moselle a traversé la Wittlicher Senke et que, par conséquent, il y a eu deux bras entre Schweich et Mülheim/Lieser, ce qui confirme les idées de Grebe (1881). A l'aide de cette méthode on a pu prouver de plus que le loess répandu dans la Trierer et Wittlicher Talweite provient des sédiments de la Moselle, et a été emporté par le vent.Краткое содержаниеВ плейстоценовых оса дках реки Мозель и нек оторых ее притоков при исследовании тяжело й фракции удается уст ановить значительный процен т непрозрачной компон енты. Спектр прозрачн ых тяжелых минералов проявляет мало разнообразия. В и зготовленных шлифах определили непрозрачную компоненту тяжелой ф ракции. Результаты ис следования показали, что эта компонента их плейст оценовых осадков рек и Мозель значительно отличал ась от таковой ее притоко в, т.к. до 50 % зерен первой составляли ооиды бурого железа, происх одящие из формации Minnette, Люксембург. Таким образом, вопрос о происхождении широ ко распространенного г алечника в районе виттлиховой впадины, а также его характеристика были решены. Доказыватеся также, что река Мозель текла в периоды от ОМТ до UMT и через эту впадину и д о этого времени сущес твовало расщепление русла реки Мозель между Шве йхом и Мюльгейм/Лизер ом. Т.е. предположения ГРЕБЕ (1881 г.) подтвердили сь. Кроме того доказано, ч то лёссовые отложени я в долинах у Виттлиха и Трира речного происх ождения и образовали сь из седиментов реки Мозе ль. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 22
    Publication Date: 1974-12-01
    Description: Краткое содержаниеК началу палеозоя в Ар гентине отмечают три геотектонические ед инницы: 1) центральный кратон; 2) ортогеосинклиналь н а западе; 3) интракратоническую область на востоке. На основании морфологи ческих единиц, возникших в течение развития ге отектонического пла на, обсуждаются региона льные распределение и стра тиграфия древнпалео зойских пород от кембрия до си лура. В северной Аргентине Subandine Sierren, Ostkordillere и Punaсохранились полностью свиты обще й мощностью в 9100 м. В Transpampinen Sierren залегают только сви ты ордовика — Tremadoc до Llanvirn — о бщей мощностью в, по-крайне й мере, 3850 м. В предкордил ьерах западной Аргентины свиты мощностью в при мерно 6000 м составлены и з почти полностью сохранившихся слоев, причем ордовик разви т наиболее полно. В Sierren San Rafael (Mendoza), в северных и южных Sierren у Буэнос-Айреса, на северопатагонском к ратоне Neso и бессейне Chaco-Parana э ти слои сохранились очень неполно, или даж е не установлены. Опис ываются литологические особенности стратиг рафических единиц и о бсуждается их взаимоотношения.RésuméOn peut, au commencement du Paléozoïque, distinguer en Argentine trois unités géotectoniques: 1. la région cratonique centrale, 2. l'orthogéosynclinal à l'Ouest, et 3. la région intracratonique à l'Est. La répartition régionale et la stratigraphie des roches du Paléozoïque inférieur (Cambrien à Silurien) sont décrites sur la base des unités morphostructurales apparues au cours du développement du plan géotectonique. Au Nord de l'Argentine (les chaînes subandines, la Cordillère Orientale et le Puna) la succession stratigraphique est complète avec une puissance de 9.100 m. Dans les Sierras Transpampines, seul l'Ordovicien (Tremadoc-Llanvirn) existe avec une puissance minimum de 3.850 m. Dans la Précordillère de l'ouest argentin, la sucession est complète avec une puissance minimum de 6.000 m dans laquelle l'Ordovicien a le plus grand développement. Dans les Sierras de San Rafael (Mendoza), les Sierras Septentrionales et Méridionales de Buenos Aires, le Nesocraton Nordpatagonien et le bassin du Chaco-Parana, la succession est incomplète ou très peu connue. Dans chaque cas on décrit les unités lithologiques connues et on indique leurs rapports stratigraphiques respectifs.ResumenAl comienzo de la era Paleozoica quedaron diferenciadas en el territorio argentino tres unidades geotectónicas: 1. región cratónica central, 2. faja ortogeosinclinal en el oeste y 3. región intracratónica en el este. Sobre la base de las unidades morfoestructurales que surgieron del desarrollo del diseño geotectónico, se describe la distribución regional y estratigrafía de las rocas del Paleozoico inferior (Cámbrico hasta Silúrico). En el norte argentino (Sierras Subandinas, Cordillera Oriental y Puna) la sucesión estratigráfica es completa con un espesor de 9.100 metros. En las Sierras Transpampeanas solo esta representado el Ordovícico (Tremadociano-Llanvirniano) con un espesor mínimo de 3.850 metros. En la Precordillera del oeste argentino, la sucesión es completa con un espesor mínimo de 6.000 metros correspondiendo al Ordovícico el mayor desarrollo. En las Sierras de San Rafael (Mendoza), Sierras Septentrionales y Australes de la provincia de Buenos Aires, nesocratón nordpatagónico y cuenca del Chaco-Paraná, la sucesión es incompleta o poco conocida. En cada caso se describen las unidades litológicas reconocidas y se indican las respectivas relaciones estratigráficas.At the beginning of the Paleozoic era three geotectonic units were already constitued in the argentine territory: 1. central cratonic region; 2. ortogeosynclinal belt in the West, and 3. intracratonic region in the East. On the basis of the morphostructural units that emerge out of the development of the geotectonic pattern, the regional distribution and stratigraphy of the Lower Paleozoic rocks are described (Cambrian to Silurian). In the Northern Argentina (Subandine ranges, Eastern Cordillera and Puna) the stratigraphical sequence is complete with a thickness of 9.100 meters. In the Transpampean Ranges only the Ordovician (Tremadoc-Llanvirn) is represented with a minimum thickness of 3.850 meters. In the Precordillera of Western Argentina the sequence is complete with a minimum thickness of 6.000 meters, the Ordovician being the most developed. In the San Rafael ranges (Mendoza), the Northern and Southern ranges of the Buenos Aires province, the Northpatagonian nesocraton and the Chaco-Parana basin, the succession is incomplete or little known. In each case the recognized lithological units are described and their respective stratigraphical relations are indicated.ZusammenfassungZu Beginn des Paläozoikums können in Argentinien drei geotektonische Einheiten unterschieden werden: 1. Zentral-Kraton, 2. Orthogeosynklinale im Westen, 3. Intrakratonisches Gebiet im Osten. Auf der Grundlage der morphogeologischen Einheiten, die im Laufe der Entwicklung des geotektonischen Plans entstanden, werden regionale Verteilung und Stratigraphie der altpaläozoischen Gesteine (Kambrium bis Silur) beschrieben. In Nordargentinien (Subandine Sierren, Ostkordillere und Puna) liegt eine vollständige stratigraphische Abfolge vor, die etwa 9100 m mächtig ist. In den Transpampinen Sierren liegt nur das Ordoviz vor (Tremadoc bis Llanvirn); die Mächtigkeit ist mindestens 3850 m. In der Vorkordillere von Westargentinien ist die sehr vollständige Abfolge mindestens 6000 m mächtig, wobei das Ordoviz am vollständigsten entwickelt ist. In den Sierren von San Rafael (Mendoza), den nördlichen und südlichen Sierren von Buenos Aires, dem nordpatagonischen Nesokraton und dem Chaco-Paraná-Becken ist die Abfolge unvollständig bzw. sehr wenig bekannt. In allen genannten Fällen werden die bekannten lithologischen Einheiten beschrieben, und es werden die stratigraphischen Beziehungen erläutert. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 23
    Publication Date: 1974-12-01
    Description: Les feldspaths du Grès bigarré, leurs modifications, leur granulométrie et leur distribution spatiale ont fait l'objet d'examens aux Rayons X, comme aussi par des méthodes optiques et chimiques, dans près de 1100 échantillons provenant de régions du Grès bigarré de la République fédérale allemande et des Vosges. Par application de méthodes statistiques, on a calculé des fractions feldspathiques presque indépendantes de la dimension des grains; on y a distingué, d'après leur distribution dans le sédiment, quatre courants de sédimentation principaux, et on a discuté leurs relations avec les unités lithostratigraphiques du Grès bigarré. Un courant sédimentaire presque sans plagioclase d'origine sud-ouest s'étendait, au Grès bigarré inférieur et au Grès bigarré supérieur, probablement jusque dans le nord de la Hesse, au Grès bigarré moyen jusqu'au centre de la dépression du Weser au sud de la Basse Saxe. Il se heurta sur son flanc sud-est et est à des déjections de sable venant du Massif de Bohême, ayant une granulométrie et un contenu feldspathique différent, qui, vers le Nord s'enrichissaient en plagioclase. Dans le Nord de la Hesse et dans le sud de la Basse-Saxe, elles se répandirent jusqu'au flanc ouest de la dépression du Wéser. Au Grès bigarré moyen, celle-ci constituait en partie une région d'interférence entre courants sédimentaires dirigés sud-nord, et sud-est-nord-ouest.ZusammenfassungEs wurden die Feldspäte des Buntsandsteins, ihre sekundären Änderungen, Korngrößenabhängigkeit und räumlichen Differenzierungen an etwa 1100 Proben aus den Buntsandsteingebieten der BRD und Vogesen mit röntgenographischen, optischen und chemischen Methoden untersucht. Unter Anwendung statistischer Methoden wurden quasi korngrößenunabhängige Feldspatanteile berechnet, nach ihrem Verhalten im Sedimentkörper vier primäre Hauptmaterialströme unterschieden und ihre Beziehungen zu lithostratigraphischen Einheiten des Buntsandstein diskutiert. Ein weitgehend plagioklasfreier Sedimentstrom südwestlicher Herkunft reichte im Unteren und Oberen Buntsandstein sehr wahrscheinlich bis Nordhessen, im Mittleren Buntsandstein bis in das Zentrum der Weser-Senke in Südniedersachsen. Er wurde an seinen südöstlichen und östlichen Flanken „bedrängt“ durch Schüttungen der Böhmischen Masse von andersartiger Körnung und Feldspatführung, die in nördlicher Richtung stets plagioklasreicher wurden. In Nordhessen und Südniedersachsen reichten sie bis auf den Westflügel der Weser-Senke. Diese bildete im Mittleren Buntsandstein teilweise einen Interferenzbereich S-N-und SE-NW-gerichteter Sedimentströme.Краткое содержаниеВ 1100 пробах из районов п естрого песчаника Ге рмании и Вогез различными физико-химическими м етодами исследовали полевые шпаты пестрых песчаников, их вторич ные изменения, зависи мость от гранулометрии и прос транственные различния. С помощью с татистических метод ов подсчитали полевошпатовую комп оненту, не зависимо от ее размерности, и по ее ра спределению выделили в осадочным материало 4 первичные зоны приноса. Обслуждается также с вязь этой компоненты с литостратиграфичес кими единицами пестрых пе счаников. Некий почти свободный от плагиоклаза поток осадков с юго-западно й зоны сноса простира ется в нижних и верхних свитах пестрого песч аника, вероятно, до сев ерной части провинции Гессен, а в средних свитах —до центральной впадины в районе реки Везер в южной части провинции Нижн яя Саксония. На юго-вос точном и восточном крыльях эти отложения « отодв инуты » отложениями Б огемского массива, характеризу ющегося иной размерностью зе рен и другим соотноше нием полевошпатной компоненты. Эти отлож ения постепенно обог ащаются плагиоклазом по напр авлению к северу, и достигают в северной части прови нции Гессен и на юге провинции Нижняя Саксония западного к рыла впадины реки Везер. В средних свитах пест рых песчаников они об разуют частично область нал ожения потоков с отложениям и, простирающимися в ю го-северном и юговосточном —северозападном нап равлениях.The feldspars of the Buntsandstein, their postdepositional alterations, dependance of grain size, their regional distribution and palaeogeographic significance were investigated. The work was based on X-Ray, optical and chemical investigations of about 1100 samples from the Buntsandstein areas in Western Germany and the Vosges. By statistical means feldspar portions independent from grain size were calculated and four different sedimentstreams were identified. The relation of these streams to stratigraphic units is discussed. One stream originated from the south-western margins of the basin, it is very poor in plagioklase and it reached most likely northern Hessen during Lower and Upper Buntsandstein time. During the Middle Buntsandstein it reached the centre of the Weser Basin in southern Niedersachsen. It was „oppressed“ at its southeastern and eastern flankes by sediment streams originating from the Bohemian Massif. They are characterised by a different granulation, by different feldspar content, and by increasing plagioklase content. In northern Hessen and southern Niedersachsen they reached the western flank of the Weser Basin. During the Middle Buntsandstein this basin had partly been an interference area of S-N and SE-NW sediment flows. ©1974 Ferdinand Enke Verlag Stuttgart
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  • 24
    Publication Date: 1974-07-01
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  • 25
    Publication Date: 1974-03-01
    Description: The solubility of alumina in complex orthopyroxenes crystallised in equilibrium with garnet has been determined over the pressure-temperature range 8–30 Kb and 800–1250° C. The results are in good agreement with predictions made using the simple thermodynamic model of Wood and Banno (1973). The model has been refined using a combination of the new data on orthopyroxenes of about En_60Fs_40 (with variable calcium content) and previously published data on more magnesian systems. Given analyses of coexisting Orthopyroxene and garnet in natural assemblages it is possible to calculate a P-T curve for the rock which should, in most cases, be accurate to within 2 or 3 kbar. ©1974 Springer-Verlag
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  • 26
    Publication Date: 1974-03-01
    Print ISSN: 0010-7999
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  • 27
    Publication Date: 1974-03-01
    Description: Experimental and theoretical considerations indicate that the distribution coefficient for iron and magnesium between coexisting garnet and cordierite increases with temperature in the assemblage cordierite-garnet-sillimanite-quartz. This conclusion is confirmed by distribution coefficients from natural garnet and cordierite from geologically well defined settings. The only published calibration which incorporates this feature is that of Currie (1971), and this is the only calibration which can be qualitatively correct although it may be wrong in detail. Other calibrations encounter catastrophes, particularly in andalusite-bearing assemblages. ©1974 Springer-Verlag
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  • 28
    Publication Date: 1974-03-01
    Description: Trace element data are presented for sixteen gabbro (hyperite)/amphibolite pairs which were collected from geological situations where it seems clear that the amphibolite formed from material similar in composition to that of the adjacent hyperite. The metamorphism of hyperite to amphibolite was not isochemical with respect to some trace elements. Cl, V and Rb were increased, as possibly was Zr. S and Zn were diminished, as possibly was Co. Sr and Ba are rather constant in the hyperites and appear to have been irregularly dispersed during the amphibolitisation. The trace element movement patterns are consistent with the known changes in the major elements, which have been reported earlier (Elliott, 1973). The introduced material was added during metamorphism under amphibolite facies conditions, by upward migration from an originally subjacent granulite facies zone. The evidence supports a hydrous fluid diffusion process for the mechanism of transfer. ©1974 Springer-Verlag
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  • 29
    Publication Date: 1974-03-01
    Description: In the acid volcanic rocks of the Cerberean Cauldron of Central Victoria, four almandine garnet types can be distinguished. Types 1 and 2 are the most important. Type 1 garnets, about 1 mm across, euhedral and free of inclusions, occur mainly in the Rubicon Rhyolite. Type 2 garnets, up to 1 cm across, often irregular and always with inclusions, are most abundant in the Lake Mountain Rhyodacite. Type 1 garnets are enriched in Fe and Mn and depleted in Mg and Ca with respect to Type 2 garnets. Zoning patterns in Type 1 garnets show enrichment of Fe and Mn in the cores. Conversely Type 2 garnets have Fe and Mn enriched rims, although the zoning is frequently less regular. Fe rich cordierite occurs, mainly in the Rubicon Rhyolite, as nearly euhedral sixlings, without inclusions. They are frequently altered but where fresh show zoning patterns like those of the Type 1 garnets. These characteristics are best explained if the Type 2 garnets and cordierite are residuals of high grade metamorphic assemblages in granitic liquids produced by partial melting of pelitic rocks. Type 1 garnets and biotite subsequently crystallized from the liquid and the zoning patterns of Type 2 garnets and cordierite were modified near their rims by reaction. ©1974 Springer-Verlag
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  • 30
    Publication Date: 1974-03-01
    Description: The distribution of U, Y, P, and Ca was studied with an electron microprobe in detrital zircons from paragneisses of amphibolite to granulite facies as well as in zircons formed in their present-day host rocks, such as a granite, anatectic and aplitic gneisses and a migmatite from the Southern Alps. Detrital paragneiss zircons have low trace element contents, whereas zircons formed in their present-day host rocks have elevated trace element contents. According to the isotopic U-Pb age pattern one may distinguish two types of zircon populations formed in their present-day host rocks: one which lost lead without any known exogene cause, and one the U-Pb system of which was only opened in response to a geological event. Different modes of incorporation of the trace elements in the zircon crystals are thought to be responsible for this different behaviour and are discussed. ©1974 Springer-Verlag
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  • 31
    Publication Date: 1974-03-01
    Description: The results of 63 new radiometric K-Ar and Rb-Sr measurements on metamorphic minerals from the internal units of the Western Alps show Hercynian, Permian, as well as three Alpine age groups. The first of the Alpine ages cover the period between 78 and 100 m.y. and refer to high pressure parageneses. The second group comprises K-Ar 39 to 50 m.y. ages; these values are affected by some inherited argon, as indicated by Rb-Sr measurements which point to 35–36±4–5 m.y., i.e. similar to the culmination of the Lepontine crystallization. The final group includes 15 to 30 m.y. ages. It is not yet clear which geologic processes have led to this isotope re-equilibration. Large amounts of inherited argon have been found in Alpine metamorphic minerals of the basement rocks. ©1974 Springer-Verlag
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  • 32
    Publication Date: 1974-03-01
    Description: A test of the proposition that calc-alkaline magmas are direct partial melts of underthrust oceanic crust is presented. It involves numerical evaluations of whether or not the major and trace element and isotopic composition of a Fijian calc-alkaline rock suite is consistent with these rocks representing unfractionated partial melts of oceanic crust at high pressures. Experimental data for one of the samples constrain the calculations. When compositions of liquidus minerals at 27 kb are combined with compositions of the volcanic rocks, close approximations can be made to the composition of oceanic crust only if the degree of partial melting is between ∼20% (dacite) and ∼45% (basaltic-andesite), and if accessory minerals are refractory phases. Concentrations of elements such as K, Rb, Sr, Pb, Th, and U, and 87Sr/86Sr ratios in the Fijian suite can be satisfactorily explained only if the parental material consisted of altered rather than fresh ocean floor basalt. Sediments are not likely to have been involved. Concentrations of Na, Ni, Co, Cr, Sc, V, the REE, Y, Zr, Hf, and Nb cannot be explained unless, or in some cases even if, several accessory phases are partially refractory. Therefore, partial melting of underthrust lithosphere does not seem likely to produce magmas with the composition of at least one quite typical calc-alkaline suite. ©1974 Springer-Verlag
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  • 33
    Publication Date: 1974-03-01
    Description: Various members of the KAlSi_3O_8-BaAl_2Si_2O_8 feldspar series are hydrothermally synthesized. Cellparameters of these are calculated from diffractometer patterns and found to be similar to those of Gay and Roy. A variation diagram is constructed correlating Cn-content and values of Δ_FeKα(2θ_(111)CaF_2—2θ_(004)Fs_ss), which gives $${ ext{Mol}}\% { ext{ Cn = 229}}{ ext{.83}}Delta { ext{2}} heta ---{ ext{190}}{ ext{.81}}$$ by a least square regression fitting. Phase equilibria relation in the solidus-liquidus-region for the KAlSi_3O_8-BaAl_2Si_2O_8-H_2O system at 1000 kg/cm2 are investigated. It is found to be a case of simple solid solution in a binary system, with reservations at the potassium-rich side of the system. Goranson (1938) gives a temperature of about 1000°C at 1000 kg/cm2 $$P_{{ ext{H}}_{ ext{2}} { ext{O}}} $$ for the incongruent melting of sanidine, but the authors prefer a value around 930°C at the same $$P_{{ ext{H}}_{ ext{2}} { ext{O}}} $$ . Reaction products of starting materials on the join KAlSi_2O_6-BaAl_2Si_2O_8 and KAlSiO_4-BaAl_2Si_2O_8 gave no experimental hint for replacement of K+ by Ba++. ©1974 Springer-Verlag
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  • 34
    Publication Date: 1974-03-01
    Description: Chemical analyses of over seventy lavas or dykes containing spinel lherzolite inclusions of high pressure mineralogy, show that most host magmas are of alkali olivine basalt or basanite composition with relatively rare olivine nephelinites, and olivine melilitites. The 100 Mg/Mg+Fe++ ratios of host magmas display a strong maximum at about Mg_70 consistent with partial melting of source peridotite with olivine of Fo_88–90. In contrast to these primary magmas, there occur some host magmas with 100 Mg/Mg+Fe++〈60 and with chemical compositions resembling those of classical hawaiite, mugearite, and nepheline benmoreite magmas. It is inferred that these magmas have been produced by crystal fractionation, within the upper mantle, of parental basanites or alkali olivine basalts. The presence of kaersutitic hornblende xenocrysts accompanying the lherzolite inclusions, and the nature of the chemical variation between associated basanites and nepheline benmoreites suggests that crystal fractionation has been dominated by kaersutitic hornblende, together with olivine and, in some cases, probably clinopyroxene. The mantle-derived nepheline benmoreite magmas also show similarities to some plutonic nepheline syenites. ©1974 Springer-Verlag
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  • 35
    Publication Date: 1974-12-01
    Description: At temperatures above about 1100° C degassed molten kimberlites were found to attack diamond, producing both graphite and metallic iron on the diamond surface. Using ordinary kimberlites in experiments performed at 1 Kb in a closed system, diamonds developed etch features (at temperatures above about 1000° C), consistent with attack by wet CO2, but no graphite or iron was formed on the surfaces of the diamonds. ©1974 Springer-Verlag
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  • 36
    Publication Date: 1974-12-01
    Description: Alkali amphiboles of an intermediate composition in the magnesioriebeckite-eckrite series have been found in the metamorphic terrane of Leros Island. A complete compositional gradation has been demonstrated by a series of electron microprobe scans and analyses of spots. Electron microscopic examination revealed no exsolution. The present analyses and other data indicate a closing of the Na-Ca amphiboles gap towards the magnesian end members at temperatures higher than that usually associated with the blueschist facies. ©1974 Springer-Verlag
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  • 37
    Publication Date: 1974-12-01
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  • 38
    Publication Date: 1974-12-01
    Description: Most of the Al3+ entering the pyroxenes does so by substituting for tetrahedral Si4+. This creates a charge imbalance that requires the simultaneous entry of Cr3+, Ti4+, Fe3+ or Al3+ into octahedral sites. Cr3+, because of its high crystal field stabilisation energy (CFSE), is the most important of these elements to enter the early-formed pyrosenes but it is replaced by Ti4+ later in fractionation when the Cr3+ content of the melt becomes depleted. The dependence of Cr3+ and Ti4+ on charge balance controls their partition between coexisting pyroxenes and olivines. Ca-rich pyroxene which contains more Al3+ than Ca-poor pyroxene also has more Ti4+ and Cr3+ whereas olivine, which contains negligible Al3+, has low Cr3+ and Ti4+. The Al3+ content of pyroxenes is influenced by changes in P, T , $$a_{{ ext{SiO}}_{ ext{2}} }$$ and $$a_{{ ext{Al}}_{ ext{2}} { ext{O}}_{ ext{3}} }$$ of the magma and by the nature of the ion providing charge balance in the octahedral site. Of these $$a_{{ ext{SiO}}_{ ext{2}} }$$ is dominant and variations in the Al3+ content of the Jimberlana pyroxenes correspond closely with the expected changes in the $$a_{{ ext{SiO}}_{ ext{2}} }$$ of the melt. The substitution of divalent ions, such as Mn2+ and Ni2+, in the pyroxene lattice is by replacement of Fe2+ or Mg2+ in the octahedral M _3 and M _2 sites and is therefore independent of charge balance. If there are no size restrictions, the principal factor to be considered is the CFSE the ion receives in octahedral co-ordination. Ni2+, which receives a high CFSE, partitions strongly between the early-formed pyroxenes and olivines and therefore becomes depleted in the magma with fractionation. Conversely Mn2+, which receives zero CFSE, concentrates in the magma with fractionation and becomes a more important substitute in the later-formed pyroxenes. Its geochemical behaviour is controlled by its size. The narrow miscibility gap of the Jimberlana pyroxenes and the high En content of the Ca-poor pyroxenes at the bronzite pigeonite changeover suggest that these pyroxenes crystallised at a higher temperature than pyroxenes of comparable composition from other intrusions. ©1974 Springer-Verlag
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  • 39
    Publication Date: 1974-12-01
    Description: Garnet pyroxenites and corundum-garnet amphibolites from the Dent peninsula of eastern Sabah (North Borneo) occur as blocks in a slump breccia deposit of late Miocene age. The earliest formed minerals include pyrope-almandine garnet, tschermakitic augite, pargasite, and rutile. Cumulate textures are present in two of the six specimens studied. The earlier fabric has been extensively brecciated and partly replaced by plagioclase, ilmenite, and a fibrous amphibole. The bulk composition and mineralogy of these rocks are similar to those of garnet pyroxenite lenses within ultramafic rocks. Estimated temperature and pressure for the origin of the Sabah garnet pyroxenites is 850±150° C and 19±4 kbar. ©1974 Springer-Verlag
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  • 40
    Publication Date: 1974-12-01
    Description: The compositions of metamorphic pyroxenes from blueschists in northern New Caledonia are investigated. Aegerine-augite occurs in siliceous metasediments and aegerine in some low-grade sodic basic schists. Calcic metamorphic pyroxene (omphacite and chloromelanite) appears first in metabasalts in higher grades of the lawsonite zone and is widespread in metamorphosed igneous rocks and quartzofeldspathic gneisses of the epidote zone. Omphacites in basic rocks have higher Mg∶Fe ratios and are less jadeitic than omphacites from adjacent interbedded quartzofeldspathic gneisses. With increasing metamorphic grade pyroxenes become more jadeitic and diopsidic at the expense of their acmite component. Elemental partitioning between coexisting pyroxenes, garnets and amphiboles from in situ regional metamorphic rocks is generally regular, suggesting equilibrium crystallization. Omphacite appears to be a stable phase within blueschist facies over a temperature range of at least 350° to 550° C. The “eclogitic” assemblage almandine-omphacite is stable within the earth's crust in metamorphosed sediments and igneous rocks over a temperature range of 400° to at least 550° C. No estimate of absolute pressures involved in metamorphism in the Ouégoa district can yet be made. ©1974 Springer-Verlag
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  • 41
    Publication Date: 1974-12-01
    Description: Using the method of Schreinemakers, along with other thermodynamic considerations, a phase diagram for the system CaO-MgO-Al_2O_3-SiO_2-CO2-H_2O was constructed. The phases prehnite, pumpellyite, calcite, chlorite, dolomite, quartz, tremolite, talc, zoisite, grossularite and vapor were considered in this construction. The results indicate that prehnite-pumpellyite facies mineral assemblages will only exist in equilibrium with a vapor phase in which the mole fraction of CO2 is less than 0.2 at 1 kb, and less than 0.15 at 2 kb. Although talc could theoretically be a stable phase under these conditions, its common absence from rocks of this facies probably results from the existence of an enantiomorphic point which makes tremolite-calcite-CO2 the stable assemblage at low X _CO _2, and the compositionally equivalent talc-calcite-CO2 assemblage stable at moderate X _CO _2. ©1974 Springer-Verlag
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  • 42
    Publication Date: 1974-12-01
    Description: The REE abundances and their chondrite-normalized pattern lead one to consider that the basalt from the Caroline ridge area southeast of the Marianas Arc and the one from the Puerto Rico Trench happen to be equivalent to conjugate liquid-type and solid-type materials, respectively, reflecting an equilibrium of a 20% partial melting. This line of interpretation enables us not only to assess the REE abundances in the original solid-type material (M), but also to estimate the corresponding values in the product (¯L) of a very small (say, less than 1 %) extent of a partial melting. It is also found that the relative REE abundances in a basalt from directly east of the Marianas Trench are quite the same as those thus estimated. Alternatively, it is possible to interpret this basalt as representing the residual liquid left after the primary fractional differentiation of the mantle. It is suggested that the straight-type bulk partition coefficients, the absence of the apparent europium anomaly, and the higher pressure are closely associated. ©1974 Springer-Verlag
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  • 43
    Publication Date: 1974-12-01
    Description: The pressure temperature stability of the phase Mn-cordierite hitherto not recorded as a mineral has been determined at temperatures ranging from 400° C up to the melting mainly using standard hydrothermal techniques at the oxygen fugacities provided by the buffering power of the bomb walls. Manganocordierite is a pronounced low-pressure phase with a maximum pressure stability of about 1 kb near 400° C and decreasing pressure limits at higher temperatures. Throughout the temperature range investigated the stable high-pressure breakdown assemblage of Mn-cordierite is spessartine, an Al-silicate, and a SiO_2-polymorph. Due to the variable water contents of Mn-cordierite and spessartine there is a pronounced curvature in the negative dP/dT-slope of the requisite upper pressure breakdown curve of Mn-cordierite. Only theoretical deductions were possible concerning the stable hydrous low-temperature breakdown assemblage of Mn-cordierite below about 400° C. The manganocordierites synthesized are orthorhombic “low”-cordierites with distortion indices increasing with temperature, water pressure, and duration of heating. Their mean refractive indices increase with rising contents of absorbed water in the structural channels. Based on experiments with natural material the upper temperature stability limit of the mineral carpholite must lie at temperatures below about 400° C for water pressures up to 2.5 kb. The absence of Mn-cordierite from natural rocks studied thus far cannot be explained on chemical grounds, but must be due to its narrow pressure temperature stability range. The phase may yet be discovered as a mineral in manganiferous metasediments formed by lowpressure contact metamorphism. ©1974 Springer-Verlag
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  • 44
    Publication Date: 1974-12-01
    Description: The heats of solution of synthetic anhydrous Mg-cordierite and of its high-pressure breakdown assemblage sapphirine + quartz (+ enstatite?) have been measured in a lead borate melt at 694°C. The ΔH of this reaction at this temperature and one atmosphere is 6.1±1 kilocalorie per mole of cordierite. A P-T stability diagram of cordierite relative to other synthetic phases in the system MgO-Al_2O_3-SiO_2 was constructed which satisfies the heat of reaction data and all other reliable observations pertaining to the stability of anhydrous cordierite. The stability field of cordierite is limited by boundaries of very small dP/dT slopes. The maximum pressure of cordierite stability is about 8 kilobars. Above an invariant point near 950°C the sapphirine-bearing assemblage is the stable breakdown product of cordierite. Below 950°C the stable breakdown assemblage is enstatite + sillimanite + quartz. New heat of solution data for orthorhombic enstatite are presented which allow a calculation of the lower-temperature breakdown boundary. This calculation is in good agreement with the boundary deduced above. The calculated breakdown pressure of cordierite at 700°C is 5.6±1.5 kilobars. This is much lower than estimates of earlier workers and shows that cordierite stability is greatly restricted under very dry conditions. Heat of solution data of natural low-iron cordierite and sapphirine samples are presented. These indicate that synthetic cordierite is energetically close to natural cordierite and is therefore an adequate stability model to apply to natural occurrences but that the synthetic sapphirine prepared by the breakdown of cordierite is quite different from natural sapphirine. An estimate of the breakdown relations of cordierite relative to natural sapphirine is presented, which looks quite like the diagram of the synthetic system except that the invariant point is shifted to considerably lower temperatures. A consequence of the present work is that if conditions of metamorphism were very dry, pressures of only six to eight kilobars would have been necessary to produce the dense anhydrous assemblages equivalent to natural cordierite which are found in some ancient granulites. The subcrustal pressures considered necessary by some workers should not be regarded as established by presently available evidence. ©1974 Springer-Verlag
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  • 45
    Publication Date: 1974-12-01
    Description: Abundant magnesiocummingtonite (space group P2_1/m) with Mg/(Mg+Fe) ratios between 0.85 and 0.89 occurs in lenses of schistose metaperidotite enclosed in kyanite-zone rocks of the Lepontine Alps, Ticino, Switzerland. It forms prisms and needles that extend homoaxially from cores of tremolite. Coexisting magnesian phases are olivine, orthopyroxene, talc, magnesite, and chlorite. Except for γ ∶ z , optical and structural properties of one example fall on extrapolations of existing determinative curves. Analogous to synthetic F-clinoamphiboles, zz ∶ z has a maximum at approximately 0.7 Mg/(Mg+Fe). Anthophyllite, of almost identical composition, occurs in the same region, often intergrown with cummingtonite along lamellae ‖(010) and ‖(100). Cummingtonite is believed to have partially inverted to anthophyllite during cooling. ©1974 Springer-Verlag
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  • 46
    Publication Date: 1974-12-01
    Description: A group of high grade metamorphic rocks from the Arendal area in Southern Norway has been analyzed for bulk geochemistry, and carbon and sulfur isotopic composition. A good correspondence between the composition of the Arendal rocks and common unmetamorphosed sedimentary and magmatic rocks suggests that except for some volatile compounds no mass transport took place during metamorphism. The high grade mafic rocks interlayered with the metasediments originate from basaltic tuffs and/or intrusives. Carbon occurs as graphite and also in small amounts in a still unidentified form. The carbon of the silicic metasedimentary rocks is isotopically light with an average δ 13C of −20.2‰, but significantly heavier than carbonaceous matter from unmetamorphosed Precambrian sediments. This is probably due to thermal pyrolysis of the original sedimentary organic matter and to the escape of a gas phase enriched in light carbon by reactions with the graphitic substance during metamorphism. Both the metasediments and the high grade mafic rocks have relatively high sulfur contents. The mean δ 34S values are 3.3‰ and 1.8‰, respectively. This can be explained by isotopically heavy sulfur in the original sediment. Some migration of sulfur probably has occurred from the metasediments into the metamafic rocks. No influence of the hypersthene isograd on the chemical and stable isotope composition could be detected. ©1974 Springer-Verlag
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  • 47
    Publication Date: 1974-12-01
    Description: Pressure-temperature conditions for which “andesitic” liquids (∼60% SiO_2) may coexist with mineral assemblages of the type magnesian olivine + orthopyroxene + clinopyroxene±amphibole±phlogopite have been investigated, both by means of partial melting experiments on the pyrolite model composition, and by experiments involving addition of olivine to andesite or basaltic andesite compositions at or near their liquidus temperatures. In the latter experiments, reaction relationships between quartz-normative liquid and olivine were made to proceed until olivine persisted. The composition of the final liquid in equilibrium with olivine (plus pyroxenes etc.) was then estimated by microprobe analysis of its quench products (glass, quench crystals). The inferred liquid compositions were tested for equilibrium with coexisting crystals using criteria based on mass balance within the total assemblage, equilibrium element partition relationships, and the requirement that the liquidus temperatures and near-liquidus crystalline phases of these compositions should closely match the temperature of the original olivine-addition experiment and the crystalline phases developed during it. At 1000° C–1050° C, liquids which satisfy these criteria for equilibrium with assemblages which include olivine are “andesitic” (58–60% SiO_2, 5–12% normative Qz) only at water pressures ≤ 10kb. At 15 kb, liquids in equilibrium with olivine at 1000° C and 980° C have ∼56% SiO_2, high alkali contents, and 5–10% normative olivine. Similar compositions are in equilibrium with orthopyroxene and garnet alone at 20 kb. These results show that andesitic magmas are unlikely to be produced by melting of a peridotitic mantle at pressures 〉10 kb (depths〉35 km). If hydrous, but otherwise geochemically primitive peridotitic compositions are partially melted at pressures〈10 kb, then “andesitic” products will be much more magnesian and poorer in alkalies than typical natural andesites. These conclusions raise serious difficulties for models of andesite genesis by the melting of hydrous peridotitic mantle immediately overlying Benioff zones. ©1974 Springer-Verlag
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  • 48
    Publication Date: 1974-12-01
    Description: Crustal garnetiferous metaperidotites occurring in a large garnet-amphibolite complex of the pre-Alpine Austroalpine unit are interpreted as metamorphosed cumulates within a metagabbroic intrusive complex. The garnet-coronas are a result of anhydrous reactions between olivine and plagioclase induced by high pressure metamorphism which at the same time was also responsible for the observed conversion of the gabbroic rocks to eclogites and amphibolites. ©1974 Springer-Verlag
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  • 49
    Publication Date: 1974-12-01
    Description: Biotite gneiss xenoliths included in a basanitic flow in the Causses region (France) show several kinds of partial melting. Rhyolitic glasses appear at the expense of the quartz + feldspar assemblage; initially undersaturated latitic glasses at the expense of biotite + feldspar (+ quartz); lastly hyperaluminous products derivating from large phenoblasts of alkali feldspar. The microprobe study of these glasses, of their contacts with the host lava, as well as that of the neogenic mineral phases, show that contamination occurs through, at least, four possible processes: 1. Diffusion at the interface between two liquids of contrasted composition (rhyolitic and basanitic). 2. Mechanical mixing of two liquids of less contrasted chemistry (latitic and basanitic). 3. Progressive solution of a solid phase (quartz) into the magma. 4. Vapour phase transfers. Qualitative magmatic contamination in alkalies (mainly K) and silica results from all these processes; quantitatively, the most important of them seems to be 4. ©1974 Springer-Verlag
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  • 50
    Publication Date: 1974-12-01
    Description: Three Eocene lavas from Skye, NW Scotland, have been subjected to anhydrous experimental studies within their melting ranges at pressures up to 30 kb. Two of these, an olivine-phyric magnesian alkali basalt and a near-aphyric Mg-poor transitional basalt, appear to show four-phase points on their liquidi at high pressures which are thought to have genetic significance. From experimental and mineralogical evidence, the magnesian basalt is postulated to be a primary magma, erupted without significant compositional change from its genesis by slight partial melting of a relatively Fe-rich spinel lherzolite upper mantle at about 60 km depth. The liquid seems to have had a reaction relationship with Ca-poor pyroxene (pigeonite) in the residual lherzolite. Partial crystallization of batches of this magma, delayed during its ascent at depths of about 40 km, is thought to have given rise to the Mg-poor basaltic liquids. The third lava studied experimentally, a sparsely olivine-phyric hawaiite, does not have olivine on the liquidus in any part of its anhydrous P-T diagram and therefore cannot have been derived under anhydrous conditions from olivine-saturated sources. The mineralogy and chemistry of the lavas are used to support an hypothesis that the hawaiites are products of partial crystallization of pockets of basalt magma at depths approximating to the crust/ mantle boundary beneath Skye, with $$P_{{ ext{H}}_{ ext{2}} { ext{O}}}$$ rising to sufficient values to make the residual liquids comparatively rich in normative feldspar. Finally, the genesis of all other Skye Eocene lavas is reviewed in the light of the new experimental data. ©1974 Springer-Verlag
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  • 51
    Publication Date: 1974-12-01
    Description: Zeolites, calcite, quartz, kaolinite, chlorite and other authigenic minerals occur in the non-marine sandstones of the Lower Cretaceous Blairmore Group of the southern Alberta Foothills, Canada. Zeolites are restricted to plagioclase-rich sandstones and do not occur with kaolinite. Laumontite and barian-strontian heulandite (containing up to 6.9 weight percent BaO and 4.1 weight percent SrO) generally occur as pore fillings, but laumontite also occurs within albitized plagioclase. About 80 percent of plagioclase grains examined by electron microprobe are partly to completely albitized. A structural-stratigraphic reconstruction of the areas sampled indicate maximum burial depths, including tectonic thickening, in the range 4.7 to 7.8 Km, with P load ∼1 to ∼2 Kb, respectively. A comparison of mineral assemblages in Blairmore rocks with published experimental data suggest T did not exceed ∼250°–280°C, depending on the load pressure. If P _H2O∶ P load, the presence of laumontite and albite suggest minimum T on the order of 150°–180°C. The lack of lawsonite suggests P -load 〈3Kb, which is compatible with structural-stratigraphic data. The occurrence of the alternative assemblages calcite-kaolinite-quartz and laumontite implies gradients in f _CO2/ f _HO2. Assemblages containing laumontite presumably equilibrated with fluids having X _CO2〈C0.0075. Computed ionic equilibria suggest that: 1) albite and kaolinite did not crystallize in equilibrium with one another; 2) that late-formed calcite may not have equilibrated with pre-existing laumontite; and 3) the occurrence of kaolinite in some beds and chlorite in others implies gradients in a Mg++/ a (H+)2. X-ray diffraction studies on disordered graphitic material indicate a comparable degree of graphitization between Blairmore graphitic material and that found in zeolite facies assemblages elsewhere. If log f _O2 were at least as low as that defined by quartz-magnetite-fayalite buffer, disordered graphite could not have equilibrated with fluids of the same composition as those equilibrated with laumontite or kaolinite. ©1974 Springer-Verlag
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  • 52
    Publication Date: 1974-12-01
    Description: Iron-magnesium distribution coefficients for coexisting ortho- and clinopyroxene in 22 amphibolites from the New Jersey Precambrian Highlands range from 1.40 to 1.90. No systematic areal variation of the distribution coefficient is discernable within a 700 mi2 area. The distribution coefficient is, however, systematically related to pyroxene composition. The distribution coefficient tends to increase with increasing pyroxene weight % FeO (Fe as FeO) and decrease with increasing MgO and Al_2O_3. Data from other workers indicates that the distribution coefficient versus pyroxene composition trends found in the Highlands amphibolites are also present in both igneous and metamorphic rock suites from several other areas. Possible influence of pyroxene CaO on the distribution coefficient is also indicated. The Highlands amphibolite type trends are, however, directly opposite to those previously reported for Australian granulites. Both types of trends are apparently valid since both are present in at least one instance in metamorphic rocks from a relatively small area. The causes for the development of the two types of trends are imperfectly understood. Data presented indicates, however, that the New Jersey amphibolite type trends are apparently more characteristic of Fe-poor pyroxenes, whereas, the Australian granulite type trends are more characteristic of Fe-rich pyroxenes. The distribution coefficient in the Highlands amphibolites is also systematically related to bulk-rock composition due to the sympathetic variation of pyroxene Fe-Mg content with total rock MgO/FeO(Fe as FeO). The observed range of the distribution coefficient in the Highlands amphibolites may, consequently, mostly reflect variation in bulk-rock composition and not variation in crystallization temperature. ©1974 Springer-Verlag
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  • 53
    Publication Date: 1974-12-01
    Description: Activity-composition relations for silicate solid solutions, which are necessary for equilibrium calculations on mineral assemblages, can be calculated from the compositions of coexisting minerals with a suitable mixing model. Three mixing models are considered; the subregular model, the Van Laar model and Green's model. The mixing properties calculated from solvi are compared with experimentally measured mixing properties for the systems NaCl-KCl and Zn-Co olivines for the different models. Green's model appears to be the most reliable, and the subregular model the least reliable. An equilibrium calculation on the assemblage alkali feldspar—pyroxene—quartz using activities calculated from the alkali feldspar solvus shows the considerable difference between the results from the different models. ©1974 Springer-Verlag
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  • 54
    Publication Date: 1974-12-01
    Description: The partition of Si, Al, Ti, Fe3+, Mg, Fe2+, Mn, Ca and Na between coexisting Ca-rich and Ca-poor pyroxenes from a wide variety of igneous and metamorphic rocks have been investigated systematically. Many of the distributions, and especially those for the partition of Ti, Mg, Fe2+, Mn and Na, indicate characteristic trends for pyroxenes from the various petrologic groups identified. The partition of Mg, Fe2+ and Mn correlate with inferred cooling rates, the partition co-efficients of pyroxenes from extruded and other quickly cooled rocks most nearly approaching unity. In contrast, the partition of Si and Ti and the absolute amounts of Al may be related to the physicochemical conditions prevailing during original crystallisation; Ti being particularly relatively enriched in Ca-rich pyroxenes of ultramafic associations. The trends of the compositions of the Ca-rich pyroxenes plotted in the pyroxene quadrilateral also correlate with cooling rates and comparison with the limited data available on the phase relations of coexisting pyroxenes suggests that sub-solidus chemical readjustments have occurred in both phases. ©1974 Springer-Verlag
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  • 55
    Publication Date: 1974-12-01
    Description: P, T , $$X_{{ ext{CO}}_{ ext{2}} }$$ relations of gehlenite, anorthite, grossularite, wollastonite, corundum and calcite have been determined experimentally at P _ f =1 and 4 kb. Using synthetic starting minerals the following reactions have been demonstrated reversibly (1) 2 anorthite+3 calcite=gehlenite+grossularite+3 CO2. (2) anorthite+corundum+3 calcite=2 gehlenite+3 CO2. (3) 3anorthite+3 calcite=2 grossularite+corundum+3CO2. (4) grossularite+2 corundum+3 calcite=3 gehlenite+3 CO2. (6) anorthite+2 calcite=gehlenite+wollastonite+2CO2. (7) anorthite+wollastonite+calcite=grossularite+CO2. (8) grossularite+calcite=gehlenite+2 wollastonite+CO2. In the T , $$X_{{ ext{CO}}_{ ext{2}} }$$ diagram at P _ f =1 kb two isobaric invariant points have been located at 770±10°C, $$X_{{ ext{CO}}_{ ext{2}} }$$ =0.27 and at 840±10°C, $$X_{{ ext{CO}}_{ ext{2}} }$$ =0.55. Formation of gehlenite from low temperature assemblages according to (4) and (2) takes place at 1 kb and 715–855° C, $$X_{{ ext{CO}}_{ ext{2}} }$$ =0.1–1.0. In agreement with experimental results the formation of gehlenite in natural metamorphic rocks is restricted to shallow, high temperature contact aureoles. ©1974 Springer-Verlag
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  • 56
    Publication Date: 1974-12-01
    Description: Arguments are made in favor of using variation diagrams to plot analyses of igneous rocks and their derivatives and modeling differentiation processes by least-squares mixing procedures. These methods permit study of magmatic differentiation and related processes in terms of all of the chemical data available. Data are presented as they are reported by the chemist and specific processes may be modeled and either quantitatively described or rejected as inappropriate or too simple. Examples are given of the differing interpretations that can arise when data are plotted on an AEM ternary vs. the same data on a full set of MgO variation diagrams. Mixing procedures are illustrated with reference to basaltic lavas from the Columbia Plateau. ©1974 Springer-Verlag
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  • 57
    Publication Date: 1974-12-01
    Description: Three samples of levyne and two of erionite from three different localities of Sardinia are described. In two samples, levyne and erionite are intergrown by epitaxy. The levynes exhibit close chemical compositions with Ca〉Na〉K; as for their lattice constants, a is very similar in all three samples, while c of one sample is rather smaller than that of the other two. Unit cell dimensions of both erionites and chemical composition of one are also given. In addition, the following data are reported for the levynes: refractive indices for all three samples, density for two and DTA for one. The existence of levyne-erionite intergrowth is emphasized, and support is given to the idea that this intergrowth is much more common than the literature would suggest. ©1974 Springer-Verlag
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  • 58
    Publication Date: 1974-12-01
    Description: Three new crystalline phases differing in Si/Al ratio have been synthesized from compositions along the join NiAl_2O_4-Ni_2SiO_4. Four reversible univariant equilibria involving these new phases plus Ni_2SiO_4 (olivine) have been located within the P-T region studied (1 atm–40 kb, 1000–1700° C); an invariant point occurs near 22 kb, 1150°C. All three new phases are orthorhombic. Precession photographs and electron microprobe analyses yield the following information: Phase I: 5NiO·3Al_2O_3·SiO_2 = 3NiAl_2O_4·Ni_2SiO_4, Pmma, a=5.67, b=11.51, c=8.10 (Å) Phase II: 7NiO·3Al_2O_3·2SiO_2 = 3NiAl_2O_4· 2Ni_2SiO_4, Imma, a=5.66, b=17.32, c=8.11 Phase III: 3NiO· Al_2O_3· SiO_2 = NiAl_2O_4·Ni_2SiO_4, Imma, a=5.68, b=11.49, c=8.12 Comparison with known structures suggests that these three phases plus NiAl_2O_4 spinel and high pressure Ni_2SiO_4 spinel belong to a homologous series based on a cubic close oxygen packing of the formula: M_2 n O_ n}-1 (T_ n O_3 n +1) where M and T are octahedrally and tetrahedrally coordinated cations, respectively. When n =1 the formula for spinel is obtained; n = 2 for phase I and phase III, both similar to the beta-phase of orthosilicates; and n = 3 for phase II which is related to the manganostibite structure. Similar phase equilibria and structural relations may occur on other joins of the aluminateorthosilicate type. Furthermore, the occurrence of such structural modifications between the spinel (aluminate) and olivine (orthosilicate) compositions suggests that there could be a corresponding polymorphic series between the olivine and spinel forms of orthosilicates. ©1974 Springer-Verlag
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  • 59
    Publication Date: 1974-12-01
    Description: U-Pb analyses of zircons from the southern paragneiss zone of the Gotthard massif in the central Alps indicate these rocks were derived from one or more source areas ≧ 1400 m.y. old and were strongly affected by both the Caledonian and Hercynian orogenies. Rb-Sr whole-rock analyses also appear to reflect the Hercynian event while Rb-Sr analyses of a metamorphic inclusion and a boudin indicate that these small-scale samples were affected by the Alpine orogeny. U-Pb whole rock data appear to reflect only the Hercynian event; these data, when corrected for primordial lead, furthermore yield an upper concordia intercept of 4500 m.y., possibly resulting from a U-Pb fractionation very early in the history of the earth. A more refined three-stage U-Pb evolution model yields an age of about 4480 m.y. rather than 4500 m.y. for this hypothesized early terrestrial differentiation. Geologically these data emphasize that: 1) the southern paragneiss zone of the Gotthard massif contains metasediments which have experienced the Caledonian orogeny and are at least 400 m.y. old; 2) the Hercynian episode in this region was pervasive indeed; and 3) the Alpine orogeny affected the Rb-Sr and U-Pb whole rock systems to a far lesser degree than the preceding orogenic episodes and apparently did not affect the U-Pb zircon systems investigated at all. ©1974 Springer-Verlag
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  • 60
    Publication Date: 1974-12-01
    Description: Isochemical contact metamorphism was observed in 3 localities based on 184 chemical analyses of rock samples and the significance tested using simple statistical techniques. The intrusions included gabbro, granosyenite, and granitic type rocks being intruded into respective schists, clays and shales, and schists and gneisses. Conductive heat transfer appeared to be the most important heat transfer mechanism in isochemical contact metamorphism. During isochemical metamorphism both H_2O and CO2 were rather mobile and impoverished in the metamorphic rocks. ©1974 Springer-Verlag
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  • 61
    Publication Date: 1974-12-01
    Description: The paper discusses the petrography, mineralogy, petrochemical affinities, P/T crystallization regimes and genetic aspects of four garnet clinopyroxenite inclusions from diatremes in the Gloucester area, New South Wales. Inclusion mineral assemblages (which generally display textural evidence of annealing) include garnet-plagioclase-(sulphur-rich scapolite)-clinopyroxene, garnet-hornblende-orthopyroxene-clinopyroxene and garnet-hornblende-clinopyroxene. The garnet-plagioclase clinopyroxenite inclusion possesses an essentially alkali basaltic chemistry. It probably represents a crystallized basaltic liquid whereas the petrochemical affinities of the two garnet pyroxenites carrying amphiboles are more appropriate to subcalcie clinopyroxenites with variable Mg/Fe ratios. Experimental and other data suggest that the Gloucester garnet clinopyroxenite suite crystallized at pressures of the order of 10–14 kb and temperatures in the vicinity of 1000° C. The chemical compositions of many garnet pyroxenites, occurring either as inclusions in alkali basaltic rocks or as localized facies within some alpine-type peridotites, such as those in the western Mediterranean region, suggest that they can be interpreted as lower temperature heteromorphs of “primitive” subcalcic clinopyroxenites, variable in Al contents and hy/di ratios, but retaining consistently low Ti, Na, K and P. It is suggested that many inclusions of garnet (-spinel) pyroxenite and subcalcie Clinopyroxenite, restricted to alkali basaltic rocks and their associates, originally may have been interleaved with upper mantle aluminous peridotites and that they represent partial melt products of their aluminous peridotitic hosts. ©1974 Springer-Verlag
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  • 62
    Publication Date: 1974-12-01
    Description: An experimental study of the behaviour of micaceous aggregates undergoing deformation during and after mica growth has been undertaken using pelletised powder consisting of an oxide mix with the stoichiometry of phlogopite. The influences of temperature, pore fluid content, strain, strainrate, and pre-mixing time have been examined. It is concluded that oriented growth of anisotropic crystals, due either to anisotropy of pore structure and hence permeability or to pressure solution phenomena, gives rise to most of the preferred orientation observed. ©1974 Springer-Verlag
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  • 63
    Publication Date: 1974-12-01
    Description: The iron-magnesium exchange reaction between olivine and calcium-rich clinopyroxene is formulated as a geothermometer. It is shown that the clinopyroxene M1 site must be nonideal and it is expressed as a regular solution. The appropriate mixing parameters are calculated from a set of groundmass olivine-clinopyroxene pairs from lavas for which there are groundmass iron-titanium oxide temperatures. The pressure dependence of the geothermometer is calculated from abailable experimental work, and is approximately 5°C per kilobar. Layered gabbros from the Kap Edvard Holm Complex, East Greenland, show no significant variation of temperature with structural height in the intrusion, while those of Skaergaard give temperatures which do not have a consistent variation with height. Continued equilibration during post-crystallisation cooling is a possibility in slowly cooled intrusions. Inclusions in diamond give a pressure-temperature line consistent with formation at 1300°C at 55 kb, 1400°C 72 kb and 1500°C 90 kb. Ultrabasic xenoliths in Basutoland kimberlites have similar pressure-temperature lines. Lavas, including alkali basalts, basanites, andesites and rhyolites give temperatures from 1025°C to 890° C. ©1974 Springer-Verlag
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  • 64
    Publication Date: 1974-12-01
    Description: A model is proposed to explain the distribution of titanium and phosphorus in oceanic basalts. This model is based on, the existence of titanium and phosphorus as primary components of specific mineral phases, the use of volumetric considerations to predict the stabilities of these phases and the existence of water as OH− in the mantle. If this model is correct then the distribution of titanium and phosphorus and their ratio may be used to test models for the origin of oceanic basalts. The amount of titanium and/or phosphorus is dependent on (in order of importance) the percent water in the original melt, amount of fractionation of silicate phases, and the depth. The ratio is largely dependent only on depth of partial melting, provided titanium and phosphorus are not depleted in the mantle by partial melting. A χ 2 analysis of the frequency distributions of these elements and their ratio is performed in order to test several models for the origin of basalts. From this analysis it is concluded that partial melting is the primary process for the generation of basalts but the degree of partial melting is relatively small and that the alkalinity of basalts increases with depth of partial melting. ©1974 Springer-Verlag
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  • 65
    Publication Date: 1974-12-01
    Description: Spinel, which constitutes from 0.7% to 3% of lherzolite inclusions, occurs as primary anhedral grains (chrome-rich variety) and as a secondary phase as breakdown products of garnet (alumina-rich variety). Although individual primary spinel grains are chemically homogeneous, spinels are characterized by a wide range of Cr/Al ratios and a relatively narrow range of Mg/Fe″ ratios, even in a single lherzolite sample. The chemical variations of spinels are considered to have the following origin: When garnet lherzolite enters the stability field of the spinel peridotite facies as a consequence of slow upward transport, both orthopyroxenes and clinopyroxenes are recrystallized with loss of jadeite and some Tschermak's component to reach equilibrium. A part of the Tschermak's component reacts with olivine to form pyroxene and spinel. This secondary spinel component is alloted to the primary chromian spinel. However, these reactions did not always reach equilibrium with the major constituent minerals in the lherzolites. ©1974 Springer-Verlag
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  • 66
    Publication Date: 1974-12-01
    Description: The assemblages phengite-paragonite, phengite-margarite and phengite-paragonitemargarite are very common in metasediments of a N-S profile in the middle sector of the Hohe Tauern. The Si4+-content of phengite shows no regular change with increasing temperature from north to south along the profile. The variations in the d _002 basal spacings of phengite coexisting with paragonite are not only dependent on the Na+ content of phengite but also on the Mg2++Fe2+ content of the micas. Neither the sodium content in phengite nor the potassium content in paragonite shows any dependence on temperature. Chemical analyses of coexisting phengite, paragonite and margarite give the extent of the three-phase-region which is characterized by a small amount of margarite in paragonite (4 Mol%), by a large quantity of Na+ in margarite (28 Mol% paragonite), and limited miscibility between phengite and paragonite. ©1974 Springer-Verlag
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  • 67
    Publication Date: 1974-09-01
    Description: The technique of template plotting of fluid bearing reactions and invariant points is extended to include the case where N H_2O+ N CO2 〈 1. This is accomplished by using normalized H_2O-CO2 fluid compositions (¯N) and reaction equilibrium constants (¯ K ). In Ln K -1/ T space, Ln¯ K is parallel to LnK but 1/¯ T is displaced a distance proportional to ( VH _2O+ V CO2) ΔH where V is reaction coefficient. The reactions from a fluid bearing invariant point ( T - N H_2O space) are straight lines that in Ln K -1/ T space intersect at a point. As the straight lines (Ln K -1/ T space) are displaced due to N H_2O+ N CO2 〈 1, this intersection point migrates along a straight path. Invariant points ( T-N H_2O space) migrate in a more complex manner. The system CaO-MgO-SiO_2-H_2O-CO2 (quartz, talc, tremolite, magnesite, calcite, dolomite) with eight fluid bearing reactions and two fluid bearing invariant points is treated at 2 Kb to demonstrate the migration of fluid bearing invariant points. The magnesite-absent invariant point occurs twice when N H_2O+ N CO2=1.0, but as N H_2O+ N CO2→0.80, the two occurrences approach each other and coincide at N H_2O+ N CO2=0.83. The invariant point then disappears if N H_2O+ N CO2 〈 0.83 because the reactions have differentially separated too much to intersect. Qualitatively this happens because the migration drives the magnesite-absent intersection point (Ln K -1/ T ) towards Ln¯ K =0. The calcite-absent intersection point migrates further away from Ln¯K=0 so the calcite absent invariant point does not disappear in N 1+ N 2 〈 0.10. Species causing N H_2O+ N CO2 〈 1 may consist of solid or fluid solutes, but those fluid solutes derived by equilibrium decomposition of H_2O-CO2 will cause ¯ N H_2O/¯ N CO2 to vary as well as N H_2O+ N CO2 so these species cause a double displacement of the equilibrium temperature relative to the system at N H_2O+ N CO2=1. ©1974 Springer-Verlag
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  • 68
    Publication Date: 1974-12-01
    Description: In a profile of ascending metamorphism, the saussuritic parageneses of two characteristic rock types, 17 acid meta-arkoses and 19 basic meta-tuffs and meta-tuffites, were investigated by microscopical and microanalytical methods. Microscopic studies reveal that the specific saussurite mineral association is dependent on the petrographic substratum. In very low stage metamorphism, granitic rocks show the following saussurite minerals coexisting with albite-rich plagioclase: 4 An-rich plagioclase+K-feldspar +4 ironhydroxide+H_2O⇌2 Fe (III) Al_2-epidote + muscovite + hematite + 2 quartz. Phyllitic and calciferous meta-arkoses exhibit predominantly the following saussurite reaction: An-plagioclase + K-feldspar + 2 ironhydroxide + CO2 ⇌ calcite + muscovite + hematite + quartz. In the reducing environment of the meta-tuffs and meta-tuffites, biotite is formed in addition to muscovite. The changing chemical composition of the saussurite minerals (plagioclase and epidote) at different stages of metamorphism was determined by 800 quantitative electron microprobe analyses. The changes found in both rock types are nearly the same. During low metamorphic stage, the An-content of the plagioclases depends on the substratum and the variable intensity of recrystallization. The Fe-content of the epidotes is dependent on the amount of iron available. The epidotes are enriched in Fe toward the transition to oligoclase-bearing parageneses. These Fe-contents cause rhythmical zoning, representing varying $${ ext{p - t - f}}_{{ ext{O}}_{ ext{2}} }$$ conditions during metamorphism. With increasing metamorphic grade the retrograde process of saussuritization is initiated. The reactants are Fe (III) Al_2-epidote, muscovite, quartz, hematite, and albite/ oligoclase. The decomposition of these minerals leads to An-rich plagioclase, biotite, microcline, and H_2O.ZusammenfassungIn einem Profil ansteigender Metamorphose werden im Stavanger-Gebiet/SW-Norwegen zwei Gesteinstypen, repräsentiert durch 17 Meta-Arkosen und Quarz-Feldspat-Gneise, sowie 19 metamorphe Tuffe und Tuffite, modellhaft auf ihre Saussuritparagenesen hin analysiert. Mikroskopische und mikroanalytische Untersuchungen zeigen eine weitestgehende Eduktabhängigkeit der Saussuritparagenesen. In calcitarmen granitoiden Edukten bilden sich schon im sehr schwach-metamorphen Stadium folgende mit Ab-reichem Plagioklas koexistierende Saussuritmineralien: 4 An-reicher Plagioklas+K-Feldspat+4 Eisenhydroxid + H_2O ⇌ 2 Fe(III)Al_2-Epidot+Muskovit+Hämatit+2 Quarz. In calcitführenden Meta-Arkosen gewinnt die Mineralreaktion: An-Plagioklas+K-Feldspat+2 Eisenhydroxid+CO2⇌Calcit+Muskovit+ Hämatit+Quarz an Bedeutung. Im reduzierenden geochemischen Milieu der Meta-Tuffe und -Tuffite tritt in diesem metamorphen Bereich als charakteristische Neubildung Biotit neben Muskovit auf. Auch in den calcitreichen tuffitischen Proben koexistieren die Saussuritkomponenten Calcit, Muskovit, Hämatit, Quarz und Biotit. Die mikroanalytisch untersuchten Saussuritmineralien Plagioklas und Epidot zeigen anhand von annähernd 800 chemischen Vollanalysen in der Entwicklung ihrer Chemismen während der Metamorphose für beide Sedimente gleiche Trends. Im niedrigtemperierten Bildungsstadium der Saussurite können die An-Gehalte der Feldspäte in Abhängigkeit vom Edukt und aufgrund unterschiedlich intensiver Rekristallisation der Sedimente relativ stark schwanken. Die Epidote sind je nach primärem Fe(III)-Angebot mehr oder weniger eisenreich. In Richtung ansteigender Metamorphose stellen sich in den Epidoten beim Übergang zu oligoklasführenden Paragenesen maximale Fe(III)-Gehalte ein, die in Form eines rhythmischen Zonarbaus die wechselnden $$P - T - f_{{ ext{O}}_{ ext{2}} }$$ -Bedingungen im Verlauf der Metamorphose widerspiegeln. Bereits hier setzt der retrograde Saussuritisierungsprozeß ein: es reagieren Fe(III)Al_2-Epidot, Muskovit, Quarz, Hämatit und Albit/Oligoklas zu anorthitreicherem Plagioklas, Biotit und Wasser. Zusätzlich bildet sich durch die Zersetzung des Al-reichen Epidots Mikroklin. Die Untersuchung zur Wechselbeziehung zwischen dem Eisengehalt des Eduktes und dem der Epidote ergibt, daß die Fe(III)-Einbaurate der Epidote in keiner Weise von den Fe(III)-Konzentrationen der Meta-Sedimente beeinflußt wird, vielmehr können eduktspezifische Intervalle für die Eisenanreicherung der Epidote nachgewiesen werden. ©1974 Springer-Verlag
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  • 69