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  • Springer  (94,358)
  • MDPI Publishing
  • 1965-1969  (94,358)
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  • 1
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The mineralogy and petrochemistry of the garnet-amphibolites from the highgrade part of the Abukuma metamorphic belt have been studied, using five analyses of rocks, five of hornblendes, three of garnets and one analysis of cummingtonite, Garnetiferous amphibolites are rich in Fe, whereas non-garnetiferous ones are rich in Mg, especially in cummingtonite-amphibolite. The chemical composition of hornblendes associated with garnet is pargasitic and rich in FeO and poor in CaO, but that of non-garnetiferous rocks is rich in MgO. The garnets are rich in almandine molecule. Mg/Mg + Fe2+ ratios of both hornblendes and garnets correspond with those of the host rocks. The development of garnet in the Adirondack metabasites belonging to the upper almandine-amphibolite and granulite facies is observed in Mg-rich rocks as well as in Fe-rich rocks, in which both garnet and hornblende are rich in Mg respectively. However, under the conditions of the andalusite-sillimanite type metamorphism as shown in the Abukuma Plateau, Fe-rich garnet occurs in Fe-rich basic rocks, but cummingtonite occurs in Mg-rich ones instead of Mg-rich garnet. Finally, the problem of polymetamorphism is discussed. The cummingtonite-amphibolite may be the product of polymetamorphism, and Mg-rich garnet which had been present previously was decomposed to cummingtonite and plagioclase by the subsequent regional metamorphism of andalusite-sillimanite type.
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  • 2
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Distribution of elements in coexisting minerals—biotite, hornblende, augite, hypersthene and plagioclase in charnockitic rocks of West Uusimaa Complex, Finland, is mostly orderly indicating a close approach to chemical equilibrium. The distribution of iron and magnesium in coexisting hornblende and pyroxenes of basic charnockites and other rocks of granulite facies from several different areas is also orderly but the variation in the fugacities of H2O and H2 may cause a disorderly distribution locally in some rocks. The probable oxidation or reduction reactions are discussed on the basis of thermochemical and mineralchemical data.
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  • 3
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Neue Mikrosonden-, Röntgenfluorescenz- und Emissionsspektraldaten von Anorthoklas aus den Khombenporphyren des Kilimandscharo werden mit den klassischen Analysen von Fletcher und Hyland (1887/88) verglichen und ein Präparationsverfahren zur RF-Analyse kurz beschrieben.
    Notes: Abstract The chemical composition of anorthoclase from Mt. Kibo has been studied by means of microprobe, X-ray fluorescence and optical emission analysis. The preparation technique for X-ray fluorescence analysis is shortly described.
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  • 4
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    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The determination of the fluorine content of courmalines yielded 0.28% as an average value for schorlites and dravites and 0.97% for elbaites. The plot of the fluorine contents against the lithium contents shows that the distribution of projection points for pink or green elbaites differs from that for lithian indigolites. Tourmalines are poorer in fluorine than lightcoloured micas at the same stage of pegmatite evolution. Individual regions with pegmatite occurrences can be characterized as rich or poor in fluorine according to the fluorine contents in the tourmalines and micas contained in the pegmatites.
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  • 5
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Crystalline rocks from breccias of the Ries basin, Germany, contain highly deformed quartz. Various planar deformation structures could be observed and classified into five different types: (1) Decorated planar elements, (2) Non-decorated planar elements, (3) Homogeneous lamellae, (4) Filled lamellae, (5) Planar fractures. All these structures are parallel to crystallographic planes: {10¯13}, {10¯12}, {10¯11}, {0001},{11¯21}, {11¯22}, {21¯31}, {51¯61}, {10¯10}. The most typical and most abundant planar structures are decorated and nondecorated planar elements parallel to {10¯13} and {10¯12}. Planar fractures are parallel to {0001} and {10¯11} and form at lower stress levels, probably earlier than the planar elements. Quartz containing planar elements, especially of the non-decorated type, has lower density, index of refraction and birefringence than normal quartz. This “quartz” is apparently a mixture of an amorphous phase and crystalline quartz, the amount of which can be calculated using average density or refractive index. Comparison of planar quartz structures found in tectonites and those produced artificially under static or dynamic high pressure conditions demonstrates that Ries quartz closely resembles deformed quartz recovered from shock wave experiments. The planar structures found in Ries quartz have been formed by shock wave actions with peak pressures in the 100–400 kbar range. Planar elements are explained to be traces of gliding processes during shock loading visible due to the fact that a high pressure phase (stishovite and/or a stishovite-like glass phase) has been produced along the glide planes. Upon pressure release most of the high pressure phase was transformed into an SiO2-glass (diaplectic glass). In comparison with experimental data the amount of residual crystalline quartz as well as type and orientation of planar structures in the quartz grains are clues to estimate the peak pressures responsible for these deformations. Shock waves with peak pressures exceeding about 400 kbar completely transform quartz into diaplectic SiO2-glass.
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  • 6
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract An empirical method is described whereby the sequence of textural changes in pelitic rocks from one zone to the next may be reconciled with the balanced metamorphic reaction inferred to have been in progress. It consists in deducing from the textures of a single thin section a set of metasomatic cation-exchange reactions, which proceed in different microscopic domains of the rock, but which add up on the scale of the whole thin section to give the balanced metamorphic reaction. Each metasomatic subsystem is closed to aluminum, but open to the more mobile cations, which are free to diffuse from one subsystem to another, subject to the requirement of short-range electrostatic neutrality, and to the assumption that the system is closed on the scale of the whole thin section. Evidence in support of the central postulate that aluminum is relatively immobile is found in 1. the preservation of bedding laminations, on a finer scale than the staurolite porphyroblasts which transect them without disrupting them. 2. The fact that quartz, the only abundant aluminum-free mineral in pelitic rocks, is by far the most common mineral in veins and “pressure shadows”. 3. The fact that the reactions so deduced provide reasonably precise descriptions of such common textures as the sillimanite needles in biotite and quartz, and the abundant quartz “inclusions” in staurolite.
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  • 7
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Electron-microprobe analyses of the feldspars and associated ferromagnesian minerals in the peralkaline volcanics, comendites and pantellerites, are presented together with new data on the major and trace-elements of the rocks and residual glasses. The feldspar phenocrysts in the pantellerites span a narrower range (Or33–Or39) than those of the comendites (Or30–Or46); both sets show only limited increase in Or outwards, and the zoning is greatest in quartz-bearing assemblages. The feldspar microlites in the residual glasses are invariably more potassic (2–4% Or) than their associated phenocrysts. In pantellerites the feldspars become more potassic as the residual liquids become more sodic; thus the most potassic feldspar is found in the most sodic (and peralkaline) pantellerite. Of the ferromagnesian phenocrysts, aenigmatite is the most ubiquitous and is commonly associated with hedenbergite±fayalite, or ferrorichterite; in the later stages of crystallization (groundmass), it is associated with acmite, arfvedsonite and tuhualite. Aside from slight variation in Ti/Fe+Ti ratio, aenigmatite is virtually constant in composition. The pyroxenes from the different assemblages have zones which together almost span the range acmitehedenbergite. Both ferrorichterite and arfvedsonite incorporate F but not Cl, and are slightly potassic. Tuhualite exists as two varieties; one blue and potassic, the other violet and sodic; both varieties reject halogens. Using (estimated) free-energy data, a field in fo2, T space is postulated in which Fe-Ti oxides are absent; their place is taken by pyroxene and aenigmatite. The no-oxide field will be intercepted by a cooling liquid in which peralkalinity is increasing and in which fo2 is near but above the FMQ buffer. The characteristic pattern of trace-elements in peralkaline volcanics (e.g., high Nb, Ta, Zr, Mo, Zn, Cd, R.E, etc; low Sr, Ba, Mg) are considered to be as much evidence for the peralkaline (salic) condition as of the genetic process. Several lines of evidence suggest that at liquidus temperatures, peralkaline rhyolites are essentially anhydrous.
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  • 8
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Aus randlichen Teilbecken des Tuz Gölü („Salzsee“), Türkei, werden bis zu 40 cm große, über dem Wasserspiegel des Salzbeckens liegende „Salzschirme“ beschrieben, deren einzelne Anwachsstreifen verschiedenen Wasserständen bei der Evaporation des Beckens entsprechen. Die Schirmform kann durch bevorzugtes Horizontal-Wachstum der NaCl-Kristalle in der obersten Wasserschicht bei gleichzeitig sinkendem Wasserspiegel gedeutet werden. Ansatzpunkte für die Schirmbildung sind im Sediment steckende NaCl-inkrustierte Pflanzenstengel, die in das Becken eingeschwemmt wurden.
    Notes: Abstract “Salt umbrellas” with a maximum diameter of 40 cm are a special form of NaCl growth. They occur above the water surface of evaporating Tuz Gölü (“Salt Lake”) in Central Anatolia, Turkey. The different growth rims of the umbrella correspond to the different water levels during evaporation of the basin. The umbrella-like shape is best to be explained by the fact that within the uppermost water layer (highest NaCl-concentration) NaCl-crystals grow preferentially in horizontal direction while the water level is steadily sinking. Small plant-stems having been brought into the basin and incrusted by NaCl act as crystallization centers for the formation of the umbrellas.
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  • 9
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Natürliche Glieder der Pyromorphitgruppe wurden mit einer Elektronen-Mikrosonde untersucht. Bei allen untersuchten Proben tritt gegenseitige isomorphe Ersetzung des Phosphors, Arsens oder Vanadins auf. Die fast reinen Endglieder zeigen dabei einen ziemlich gleichmäßigen, geringfügigen Einbau der Nebenkomponente unabhängig vom optischen Zonarbau, während für die Mischglieder starke zonare Schwankungen in der chemischen Zusammensetzung in Abhängigkeit von den optisch erkennbaren Zonen typisch sind. In einem Falle wird zonar Blei isomorph durch Kalzium ersetzt. Der Chlorgehalt scheint von keiner der übrigen Komponenten abhängig zu sein und unterliegt nur z.T. zonaren Schwankungen. Zonarbau durch Farbänderungen und Einbau von Fremdpartikeln, fast nur bei den Mischgliedern zu finden, bedingt zumeist entsprechende zonare chemische Veränderungen der Phosphor-, Arsen- oder Vanadingehalte. Zonarbau infolge unterschiedlicher optischer Orientierung kann sowohl ohne chemische Zonen vorkommen (bei den Endgliedern), als auch mit gleichlaufenden Veränderungen der Komponenten bei den Mischgliedern. Zonarbau als Folge unterschiedlicher optischer Orientierung, Felderteilung und Zweiachsigkeit haben nach den vorliegenden Untersuchungen nicht isomorphen Ersatz als Ursache; Veränderungen der physikalischen Bedingungen während oder Sekundärvorgänge nach Beendigung des Wachstums der Kristalle könnten eine Rolle gespielt haben. In Frage kommt auch eine Abweichung von der hexagonalen Symmetrie; eine kürzlich von U. Keppler (Karlsruhe) durchgeführte Einkristall-Untersuchung einer Mimetesit-Zone ergab für diese eine monokline Symmetrie (im Druck). Das Auftreten von diffusen Reflexen oder Doppellinien in den Röntgendiagrammen der Mischglieder kann zwanglos durch die gegenläufigen Schwankungen der Phosphor-, Arsen- oder Vanadin-Gehalte gedeutet werden.
    Notes: Abstract Natural members of the pyromorphite group, pyromorphite Pb5(PO4)3Cl, mimetite Pb5(AsO4)3Cl, kampylite Pb5(PO4, AsO4)3Cl, and vanadinite Pb5(VO4)3Cl were investigated by the electron microprobe method. Mutual isomorphic replacement of P, V and As was observed even in the purest available end members occurring in nature. The frequently appearing zoned structure, observed in thin sections, may or may not coincide with corresponding chemical changes with respect to the V, As or P contents, mainly for the intermediate members, while for the rather pure end members nearly no connection was found between optical zones and chemical composition (also as to the division of basal sections into six triangular areas).
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  • 10
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Chemical-optical and X-ray analysis of some perthite groups, from cristalline rock massifs, came into evidence that in perthites with the same order degree of Si/Al distribution, the observed variations of 2VX are strictly related to the Na content in the potassic phase; i.e. 2VX decreases when Ab mixed in the K-phase increases. This fact suggests that for any Si/Al, distribution, not in equilibrium, exists a certain range of non equilibrium mixing between Or and Ab.
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  • 11
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The gas-chromatographic behaviour (selectivity performance for cyclohexanebenzene and m-, p-xylenes pairs separation) of dimethyldioctadecylammonium complexes with kaolinite, fire-clay, halloysite, attapulgite, hectorite and various montmorillonites, nontronites and vermiculites has been investigated. The obtained data indicate the influence of specific surface and charge density on relative retention value (α), and of substitution location (tetrahedral versus octahedral sheet) within the clay lattice on selectivity. Hence, derivatives with nontronites and vermiculites, that is the clay minerals where the principal lattice substitutions are predominantly occurring within the tetrahedral sheet and possessing the highest surface charge density, are very effective sorbents for gas-chromatographic use. The application of gas-chromatography as investigation tool of clays surface is suggested.
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  • 12
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    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Résumé Les températures de réaction des relations: kaolinite+quartz=pyrophyllite; kaolinite=andalousite+pyrophyllite et pyrophyllite=andalousite+quartz ont été déterminées pour des pressions totales de 1000 et 2000 bars, en présence d'eau. A partir de ces données et de celles des travaux antérieurs sur le système Al2O3-SiO2-H2O, un diagramme de phase comportant 4 points invariants, mettant en jeu 11 réactions univariantes, a été construit dans un espace P.T. Cette analyse permet de prévoir les limites de stabilité des silicates d'alumine hydratés dans un domaine de températures et de pressions allant jusqu'à 6 kbs. et 550° C.
    Notes: Abstract The temperature of reaction for kaolinite + quartz=pyrophyllite, kaolinite=andalusite +pyrophyllite and pyrophyllite=andalusite+quartz, have been determined for total pressures near 1000 and 2000 bars, in the presence of H2O. Using these determinations and a compilation of previously existing work in the system Al2O3-SiO2-H2O, a phase diagram has been constructed in P.T. space which indicates four invariant points involving 11 univariant reactions. This analysis outlines the stability limits for the hydrous aluminiumsilicates in the pressure-temperature range up to 6kbs. and 550° C.
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  • 13
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Crystal-melt relations at a water vapour pressure of 1 kilobar have been determined for planes at 3, 5, 7.5, and 10 weight per cent anorthite in the system NaAlSi3O8KAlSi3O8-CaAl2Si2O8-SiO2. The ratio of the silicate components in the liquids which are in univariant equilibrium with plagioclase, alkali feldspar, quartz and gas are Ab31∶Or28∶Q38∶An3 (weight per cent) at 730°±5–10° C, Ab21∶Or34∶Q40∶An5 at 745°±5–10° C and Ab10∶Or39∶ Q43.5∶An7.5 at 780°±10° C. The univariant curve on which the above compositions lieoriginates on the H2O-saturated Or-An-Q plane at a composition containing less than 10 weight per cent An and terminates within 1.5 weight per cent An of the H2O-saturated Or-Ab-Q plane. Experimental data for the synthetic system have been used to illustrate a discussion on the partial melting of metasediments and the possible significance of such a process with respect to the genesis of granitic rocks. Data taken from the literature (Winkler and v. Platen, 1960, 1961a) have been used to illustrate that the normative salic composition of a sediment has a strong influence on the composition of any melt which form when such a rock is subjected to high temperatures and pressures.
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  • 14
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    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Die Granodiorite und QuarzGlimmer-Diorite aus dem Intrusivgebiet von Fürstenstein (Bayerischer Wald), der Diorit des südlichen Vorspessarts mit eingeschalteten Amphibolitschollen und kalifeldspatreichen Schlieren, sowie die Diorite und Hornblendegabbros des mittleren Bergsträßer Odenwaldes wurden geochemisch verglichen. Zur Bestimmung der Haupt-, Neben- und Spurenelemente in 65 Gesteinsproben wurden röntgenspektrometrische, titrimetrische, flammenphotometrische und emissionsspektralanalytische Methoden herangezogen. Zusätzlich fanden 33 chemische Analysen aus der Literatur Verwendung. Die untersuchten Gesteinstypen reichen vom granodioritischen (Bayerischer Wald) über den dioritischen (Spessart) bis zum hornblenditischen (Odenwald) Chemismus, wobei jedes der drei Untersuchungsgebiete eine mehr oder weniger deutliche Gruppierung zeigt. Innerhalb der einzelnen Dioritkomplexe ist nur ein Teil der petrographisch erfaßbaren Gesteinstypen auch durch einen spezifischen Gesteinschemismus gekennzeichnet. Während die Granodiorite des Bayerischen Waldes bis auf die relativ hohen Zr-Gehalte auch im Hinblick auf die Spurenelementführung normale Verhältnisse zeigen, sind die niedrigen Cu-, Ni- und Zn-Gehalte, sowie das hohe K/Rb-Verhältnis in den Odenwald-Dioriten und Hornblendegabbros auffällig. Trotz der großen Streubreite im Hauptchemismus dieser Proben schwanken die SrGehalte nur relativ wenig. Bemerkenswert bei den Spessart-Dioriten ist, daß diese in den Spurenelementgehalten z. T. erheblich unter den von Vinogradov (1962) angegebenen Clarke-Werten bleiben. Die im Diorit eingeschlossenen Amphibolitschollen zeigen deutlich höhere Cu-, Ni- und Zn-Gehalte, sowie niedrigere Sr-und Ba-Gehalte. Die K/Rb-Verhältnisse unterscheiden sich dagegen praktisch kaum. Der Vergleich der Odenwald-Diorite und Hornblendegabbros mit den Amphiboliten zeigt, daß letztere durch niedrigere CaO-Gehalte, etwas größere Zr-Gehalte und ähnlich niedrige Ni-Gehalte gekennzeichnet sind. Im Lichte der geochemischen Ergebnisse wird die Genese der dioritischen Gesteine diskutiert.
    Notes: Abstract The granodiorites and quartz diorites of the Fürstenstein igneous complex (Bayerischer Wald), the diorites of the Spessart crystalline area (including schollen of amphibolite, and schlieren rich in K-feldspar) as well as the diorites and hornblende gabbros of the central Odenwald igneous complex have been compared. 65 rock specimens have been analyzed for the major and minor elements Si, Ti, Al, Fe3+, Fe2+, Mn, Mg, Ca, Na, K, P, as well as for the trace elements Zn, Cu, Ni, Rb, Sr, Zr, Ba, and (semiquantitative) V, and Cr using X-ray spectrometric, flame photometric, titrimetric, and UV-spectrometric methods. 33 additional analyses (major and minor elements only) have been taken from literature. The rock types investigated vary from granodiorite to hornblendite in chemical composition. The averages of the three diorite areas plot near quartz diorite, diorite, and gabbro composition, respectively. This grouping is followed very clearly by the trace element content of Zr, Rb and Ba rather than the other ones. The bearing of the geochemical results on the genesis of dioritic rocks is briefly discussed.
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  • 15
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Basalts in the Southern Rocky Mountains province have been analyzed to determine if any of them are primitive. Alkali plagioclase xenocrysts armored with calcic plagioclase seem to be the best petrographic indicator of contamination. The next best indicator of contamination is quartz xenocrysts armored with clinopyroxene. On the rocks and the region studied, K2O apparently is the only major element with promise of separating primitive basalt from contaminated basalt inasmuch as it constitutes more than 1 % in all the obviously contaminated basalts. K2O: lead (〉 4 ppm) and thorium (〉 2 ppm) contents and Rb/Sr (〉 0.035) are the most indicative of the trace elements studied. Using these criteria, three basalt samples are primitive (although one contains 1.7% K2O) and are similar in traceelement contents to Hawaiian and Eastern Honshu, Japan, primitive basalts. Contamination causes lead isotope ratios, 206Pb/204Pb and 208Pb/204Pb, to become less radiogenic, but it has little or no effect on 87Sr/86Sr. We interpret the effect on lead isotopes to be due to assimilation either of lower crustal granitic rocks, which contain 5–10 times as much lead as basalt and which have been low in U/Pb and Th/Pb since Precambrian times, or of upper crustal Precambrian or Paleozoic rocks, which have lost much of their radiogenic lead because of heating prior to assimilation. The lack of definite effects on strontium isotopes may be due to the lesser strontium contents of granitic crustal rocks relative to basaltic rocks coupled with lack of a large radiogenic enrichment in the crustal rocks. Lead isotope ratios were found to be less radiogenic in plagioclase separates from an obviously contaminated basalt than in the primitive basalts. The feldspar separate that is rich in sodic plagioclase xenocrysts was found to be similar to the whole-rock composition for 206Pb/204Pb and 208Pb/204Pb whereas a more dense fraction probably enriched in more calcic plagioclase phenocrysts is more similar to the primitive basalts in lead isotope ratios. The primitive basalts have: 206Pb/204Pb ∼ 18.09–18.34, 207Pb/204Pb ∼ 15.5, 208Pb/204Pb ∼ 37.6–37.9, 87Sr/86Sr ∼ 0.704–0.705. In the primitive basalts from the Southern Rocky Mountains the values of 206Pb/204Pb are similar to values reported by others for Hawaiian and eastern Honshu basalts and abyssal basalts, whereas 208Pb/204Pb tends to be equal to or a little less radiogenic than those from the oceanic localities. 87Sr/86Sr appears to be equal to or a little greater than those of the oceanic localities. These 206Pb/204Pb and 208Pb/204Pb ratios are distinctly less radiogenic and 87Sr/86Sr values are about equal to those reported by others for volcanic islands on oceanic ridges and rises.
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  • 16
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    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Over the range Ca/(Ca + Na) from zero to 0.75, scapolites vary linearly between Na4Al3Si9O24Cl and NaCa3Al5Si7O24CO3, by means of a coupled replacement of Na3Si2Cl by Ca3Al2CO3. Ca includes minor Sr, Na includes K, and CO3 may include substantial SO4. From Ca/(Ca + Na) = 0.75 to 1.00, variation is between NaCa3Al5Si7O24CO3 and Ca4Al6Si6O24CO3, by means of a coupled replacement of NaSi by CaAl, as in plagioclase. Anion substitution is complete at the 0.75 point. Recalculation of scapolite analyses on the basis of Al + Si atoms = 12.0, as suggested by computed unit cell contents, offers a reasonable basis for normalization of atomic proportions. On this basis, Ca + Sr + Na + K + Fe atoms total very close to 4.0. New limits on the minor element content of scapolite are proposed. In view of the inflection at 0.75, subdivision of the scapolites at Ca/(Ca + Na) ratios of 0.25, 0.5, and 0.75 seems more logical than the 0.2, 0.5, and 0.8 limits used hitherto for marialite, dipyre, mizzonite, and meionite.
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  • 17
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The garnets of garnet-peridotite xenoliths that occur in the kimberlites of Southern Africa and the U. S. S. R. are shown to differ significantly in chemical composition. It has been demonstrated that the compositions of garnets of this type depend largely on the compositions of the media in which they grew (Rickwood, Mathias and Siebert, 1968), and thus it is concluded that the Upper Mantle in these two regions differs in chemical composition. Southern Africa is a chromiferous province and the U. S. S. R. is a ferric province.
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  • 18
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract A discussion of the transition from the “ideal hexagonal” mica structure to the “ideal ditrigonal” one, leads to the conclusion that the single mica layer may have two different structures (labelled A and B). The recent literature data show that both the A and B structures have been detected in some triocahedral layer lattice silicates found in nature. An examination of the structural stability of the A and B structures suggests that the last one may not be realized by dioctahedral layer lattice silicates. The concept of two structurally different mica layers, which however have the same lattice constants, greatly improves the understanding of polymorphism and twin laws in layer lattice silicates. The structural features of the tetrahedral sheet, octahedral sheet and interlayer region are carefully examined. Thus we can reach the following conclusions: the tetrahedal sheet is not entirely free to reduce its lateral dimensions by the mechanism of tetrahedal rotation owing to the repulsion among Obas atoms; the octahedral sheet in layer lattice silicates, may increase or reduce its lateral dimensions as compared to the lateral dimensions it has in the hydroxide minerals; the interlayer region is characterized by a regular octahedral coordination of the Obas around the interlayer cation. On the ground of these conclusions, new structural models for some selected layer lattice silicates are proposed.
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  • 19
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The diffraction, n.q.r. and optical data on plagioclase feldspars are used to derive kinetic interpretations of structural changes induced by laboratory heat treatment and by geological processes. For anorthite, the Si, Al configuration is essentially ordered except for unusual transient processes. Cooperation between Ca atoms, and random nucleation, produces a domain texture in the primitive structure which is highly sensitive to temperature. The rapid inversion from the primitive to the body-centered structure is explained by increasingly rapid “rattling” of the Ca ions in the interstices of the semi-flexible alumino-silicate framework. The weakening of “b” reflections at higher temperatures is ascribed to incipient Si, Al disorder associated with irregular vibration of the alumino-silicate framework and the Ca atoms. Quenching phenomena are explained by variation of the domain boundary texture inherited from disorder at high temperature. For albite, the Si, Al configuration changes sluggishly from an ordered to a disordered pattern, and vice versa. Kinetic data are reinterpreted using a model in which the cell dimensions depend on local rather than distant order: the major change in distant order is deduced to occur at 450–600° C. Sodic plagioclase grown at high temperature shows distant disorder of the atoms, but cell dimensions suggest development of strong local order for calcic compositions. Low-entropy plagioclases of intermediate composition show complex intergrowths and domain structures because of kinetic barriers to atomic diffusion. X-ray diffraction data for slowly-cooled specimens are consistent with nucleation of albite- and anorthite-like regions from a high-temperature disordered phase. Electrostatic energy calculations show that Na and Ca atoms, although they face smaller energy barriers for diffusion, cannot form domains until the Si and Al atoms have moved jointly. The Si, Al ordering patterns of low albite and anorthite are topologically incompatible in a continuous framework if oxygen is not to be bonded to two Al. Therefore domains of low-albite and anorthite must be separated by disordered boundaries. For intermediate compositions, An15-An75, domains remain small. The anorthite-like domains probably form at higher temperatures than the albite-like domains. The latter tend to be about the same size for all bulk compositions. The atomic positions are influenced by neighboring atoms. Upon heating rapidly, Si and Al atoms remain in position and provide a memory for reformation of an identical structure upon cooling. The framework changes shape, and some Na, Ca atoms inter-diffuse to yield a quasi-homogeneous structure with a diffraction pattern which qualitatively approaches that of high albite. Upon prolonged heating at high temperature, Si, Al atoms inter-diffuse producing nonquenchable changes to the high-albite structure. At Na-rich bulk compositions, some domains of low albite grow into large lamellae while others remain small in contact with anorthite domains producing alternate lamellae of intermediate structure type; hence the peristerite intergrowth. A similar but opposite process could cause an intergrowth of lamellae of anorthite structure interposed with an intermediate type structure. A unique low plagioclase series is not expected. Plagioclases of intermediate composition trend towards slightly different endproducts depending on the details of the cooling history. Breaks and bends in plots of physical properties, and intergrowths for certain specimens, depend on special compositional, growth and annealing factors. The intergrowth responsible for iridescence of intermediate plagioclase is ascribed to Na, K segregation prior to development of the complex domain structure. Prolonged annealing at high temperature in a dry environment is suggested. It is futile to attempt to describe low entropy plagioclases in terms of classical thermodynamics: only a kinetic interpretation based on atomic and sub-microscopic textural factors can be viable.
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    Notes: Abstract A glass of composition NaAlSi3O8 with small contents of Fe has been crystallized in the presence of water vapor under 1000 bars, at temperatures in the range of 250 to 700° C for varying periods of time. The synthetic crystals were investigated microscopically and by x-ray powder diffraction methods. Most of the crystals are twinned according to the albite law, but other twins are found too. Size and form of the crystals seem to depend on the temperature of crystallization. The optic axial angles (2V x ) of the albites being measurable on the universal stage are in the range of 50 to 100 degrees. There seems to exist a linear relation between the 2ϑ131−2ϑ1¯31 values (used as an indicator for the degree of ordering) and the 2V x values. The change of the lattice parameters from albite (D) to albite (O) is suggested to deviate slightly from linearity. In contrast to previous investigations the steady value of 2ϑ131−2ϑ1¯31 which is characteristic of the temperature of crystallization was reached more rapidly. These results suggest that small content of Fe in the glass had a catalytic effect on the Al/Si ordering.
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  • 21
    ISSN: 1432-0967
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    Topics: Geosciences
    Notes: Abstract Stilpnomelane is known to be index-mineral of lowest metamorphic facies in the northern zone of the Swiss Alps. In Montblanc-region the first stilpnomelane due to alpine metamorphism will be found in the Montblanc-granite, whereas until now the adjacent metamorphic rocks in the north of granite have not yielded any stilpnomelane. This could be explained by chemical control in the metamorphic rocks or by instability of stilpnomelane because a new formed biotite has been found in the shearing-zones in the northern part of granite and stilpnomelane is disappearing. Metamorphic reactions in the very coarse granite are bound to the limits between constituents or to the interior of larger crystals. Stilpnomelane very often has been found in microcline situated near to biotite or chlorite of primary origin. Towards the southern part of granite stilpnomelane will be found in larger quantities and occasionally a new formed chlorite will appear. This evolution is accompanied by the appearance of larger quantities of patch-perthite and chessboard-perthite in the microcline-megacrysts. Probably a green biotite coexists with stilpnomelane, but majority of alpine biotite has been formed in a later phase and is accompanied by a strong change of quartz-fabric and disappearance of stilpnomelane. One might suppose, that the change of lowest greenschist-facies (stilpnomelane) to a higher degree (biotite) even over very short distances depends more on the influence of changing chemical composition in the coexisting aqueous-gaseous phases than on a real increase of pressure and temperature.
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  • 22
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    Topics: Geosciences
    Notes: Abstract Formation of travertines from continental waters requires very special conditions. Their porous, cellular and concretionary appearance is often due to calcite incrustations on plants. Therefore the high porosity beside a very low concentration of detrital silicates must be related to a high rate of calcite accumulation (0.1 to 1 mm/year). A high rate of sedimentation from high Ca-concentrations (〉0.01%) does not occur in normal continental waters equilibrated with the atmospheric carbon dioxide. Formation of travertines is probably not an indicator of special climatic conditions as often assumed but is related to a special chemical composition of fresh waters. Creeks with continuous travertine deposition, investigated by us, contain about 200 ppm Ca. This is more than ten times the normal concentration of average continental waters. Bicarbonate concentration in these waters is five times that of equilibrium with atmospheric carbondioxide. Many of the productive waters are characterized by high sulfate concentrations and Sr/Ca-ratios (1000 Sr/Ca ranges from 9 to 22; seawater: 20). Except one from the Schwäbische Alb 15 samples (Leine-valley, Teutoburger Wald, Thüringen) are high in sulfate and Sr/Ca-ratio to be accumulated in waters with remarkable concentrations in the respective elements. The Sr/Ca-ratios cannot be explained from dissolved limestones underlying the exposed areas. The assumption of dissolution of gypsum beds very well explains our observations and data. From the S32/S34 ratio an origin from Zechstein (Upper Permian), Muschelkalk (Middle Triassic) or Keuper (Upper Triassic) deposits respectively can be assumed. Like other freshwater limestones the travertines under investigation differ from marine carbonates by their light carbon (mean δC13 −8,1) from decomposed organic matter and their light oxygen (mean δO18 −6,7) from exchange with freshwaters. The discrimination freshwater- and marine limestones in oxygen isotopes is only valid for those of low age (Upper Mesozoic to Recent). Hence the special conditions of travertine formation are related to bicarbonate spring waters which have circulated on faults where they could dissolve gypsum (and/or calcite) from subsurface beds. Additional examples of travertine deposits from Czechoslovakia (Zyka, 1958), Lüneburger Heide (NW Germany), Italy (Tivoli near Rom) and Jugoslavia can be explained as formations of either sulfate-bicarbonate or of bicarbonate waters.
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  • 23
    ISSN: 1432-0967
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    Topics: Geosciences
    Notes: Abstract Three complete analyses and one partial analysis are recorded of unzoned sodic anorthites having compositions An94,9, An94,0, An92,7 and An92 (mol per cent). Although crystallising at a high temperature the K and Sr contents are low. X-ray parameters show the material to be in a relatively high structural state comparable with material from Japanese volcanics. Available data indicate small but real differences in optical parameters between sodic anorthites of volcanic and plutonic origin but this needs further clarification. Refractive indices and specific gravities of the analysed samples are also recorded. Anorthite (An90-An100) occurs widely as phenocrysts in basic lavas and as crystal ejecta in the calc-alkaline rock suites of the circumoceanic islands. Anorthite can be precipitated from sub-alkaline magmas under certain conditions and does not require the postulation of special magmas or of contamination. It is apparent that factors other than the normative feldspar composition of the magma determine the composition of the plagioclase precipitated. Evidence from experimental work on synthetic systems indicates that an increase in both hydrostatic pressure and water vapour pressure will influence the plagioclase composition but it is not possible to evaluate these effects fully at the present time. The occurrence of anorthite is interpreted as evidence of extensive crystal accumulation at depth from fractionating basic magmas in circumoceanic calc-alkaline suites.
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  • 24
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    Notes: Abstract The High Magadi beds can be divided into a lower and an upper sequence, separated by a bed rich in Tilapia nilotica remains. The lower sequence contains one or more magadiite horizons. Through digging of trenches it has been possible to establish that the cherts of the “Chert Series” are stratigraphically equivalent to the magadiite horizons. The transition magadiite-chert has been observed in many places and may occur over a distance of less than 50 cm. It is accomplished by removal of sodium by percolating waters. The resulting bedded chert may preserve the fine lamination present in magadiite. The conversion is accompanied by many textural and structural features such as large desiccation polygons, buckling, reticulation, extrusion, casts of mud-cracks and calcite. The precipitation of magadiite is postulated to have taken place in annual increments in a stratified lake at the brine-epilimnion interface. The maximum duration is estimated at 4,000–6,000 years. Solubility measurements indicate that most Magadi waters at the present time are supersaturated with respect to magadiite and kenyaite, though no precipitation has been observed. The presence of chert chips in intraformational gravels indicates that the conversion to chert was already initiated during the magadiite precipitation interval. The inorganic mechanism for the formation of bedded chert observed at Magadi is suggested to apply also to the Dales Gorge Member of the Precambrian Brockman Iron Formation of W. Australia. Evidence for magadiite as chert precursor is found in the depositional rates, the presence of riebeckite and in textures such as macules and cross-pods. The proposed model is extended to include Precambrian banded iron formations in general and the restriction of these formations to the early history of the earth is explained by the likely compositions of waters from closed basins.
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  • 25
    ISSN: 1432-0967
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    Topics: Geosciences
    Notes: Abstract The grades of ordering as represented by I.R. and X-ray spectra for platy kaolinite, fire clay mineral, ball clay, dickite, nacrite and tubular dehydrated halloysite samples of various origin, are related. Well ordered kaolinite, has four bands 3,693, 3,668, 3,652 and 3,620 cm−1. In less ordered kaolinite, fire clay mineral and ball clay these bands have shifted a little or of the middle two, which are the weakest, only one band may be left (between brackets): less ordered kaolinite: 3,695, 3,667, 3,652 (3,653) and 3,620 cm−1; fire clay mineral 3,696, 3,668, 3,653 (3,653) and 3,621 cm−1; ball clay 3,697, 3,652 and 3,621 cm−1. Dehydrated halloysite has 3,693–3,698, 3,668, 3,650–3,654 and 3,620–3,626 cm−1 bands. In the most disordered dehydrated halloysite samples (Martinsberg and Baia Mare) only two bands are left at 3,696 and 3,624 cm−1. Dickite has four bands: 3,708, 3,656, 3,627 and 3,622 cm−1. For the lesser ordered Mexico sample it is 3,701, 3,652, 3,627 and 3,621 cm−1. Nacrite also has four bands i.e.: 3,700, 3,650, 3,627 and 3,620 cm−1. There is, apart from orientation effects, a wide variation in the absolute and especially in the relative intensities of the I.R. bands and X-ray reflections for each of the mineral groups investigated here, but of various origin. The need of a nomenclature adapted to the level of our knowledge about this matter to day and comprising all these variations included those in morphology is emphasized. Quantitative analyses, the adjective meant in the sense of an accuracy of minimal 5%, constitute a difficult problem which is perhaps even wholly impossible to solve with the conventional methods of today.
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  • 26
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    Notes: Abstract 91 biotites (53 from granites, 35 from highly metamorphic gneisses, 3 from redwitzites) were separated and analyzed for Fe, Mn, Zn, Cl, Sn, Ni, Co, Or, Cu, V, Mo, Pb. Biotites from gneisses contain much more Ni, Co, Cr, V but less Fe, Mn, Zn than those from granites. However, the distinction between biotites from gneisses and from granites on the basis of these elements is not certain. If a gneiss undergoes anatexis, the contents of Ni, Co, Cr, V, Zn and Sn of the preexistent biotite fractionate: Zn, Sn and Pe enter the anatectic melt readily while Ni, Co, Cr and V concentrate in the remaining matter (restite). Ni, Co, Cr and V are strongly positively correlated with one another but negatively with Fe and Zn, the latter being positively correlated with Pe. The chemical composition of biotites from granites depends not only on a potential degree of secondary decomposition into chlorite and muscovite but much more on the percentage of biotite in the rock: The more biotite, the higher the content of Ni, Co, Cr, V and the lower Fe, Zn and Sn in the biotite. Thus, it is possible to distinguish between normal and abnormal concentrations of an element in a biotite and in a rock. This might be useful in geochemical prospecting. Abnormal high concentrations of Sn and Zn were found in biotites from some granites which are connected with mineralizations of these elements. It is impossible hitherto to gain informations about the history and the parental material of a granitic magma from the minor elements in the rock or the biotite because their concentrations depend on how much biotite could be incorporated by the melt. The distribution coefficient of Cl between the lattice of 4 biotites and their fluid inclusions was determined to be 0,08.
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  • 27
    ISSN: 1432-0967
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    Topics: Geosciences
    Notes: Abstract Data are presented for K, Ba, Sr, Rb, Li, Ga, Mg, Mn, and Fe for twelve rhyolitic plagioclases (An28-An46), one dacitic (An53), and three andesitic plagioclases (An68-An81). Additional data are presented for Ga, Gr, V, Ni, Co, Sc, Y, La, Sr, and Ba for two augites, nine hypersthenes, and five hornblendes separated from the same rocks. Distribution factors have been calculated, using these data, and previously published results for coexisting groundmass compositions (=“liquids”). The plagioclases show a positive correlation between, and a progressive increase in K and Ba (range 0.09–0.58% and 61–610 p.p.m. respectively) with increasing Ab-content. Sr (range 465–880 p.p.m.) shows a well defined maximum between An40-An55. The plagioclases have extremely high K/Rb ratios (mostly 〉 1,000). This volcanic series is characterised by relatively Mg-rich pyroxenes and hornblendes. The augites contain higher Sc, Cr, Y, Sr, and Y relative to their coexisting hypersthenes, while the hornblendes exhibit higher Sc, V, Ba, Sr, Y, and La relative to coexisting hypersthenes. Very marked differences in concentrations of these elements exist between the rhyolitic and andesitic ferromagnesian phenocrysts. There is also evidence of a systematic distribution of Sc, V, Cr, Y, Co, and Ni between coexisting hypersthenes and hornblendes, and between these minerals and their coexisting whole rock and groundmass compositions. The data are discussed from a petrological viewpoint, as they are interpreted to indicate that the phenocrysts crystallised in the magmas in which they are found, and are not xenocrystic. No evidence of hybridisation or contamination, subsequent to the onset of crystallisation, is found.
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    Notes: Abstract Data on the distribution of iron and magnesium between coexisting olivine and pyroxene in rocks and in experiments are used to estimate the probable deviation from ideal solution in olivine and to find an approximate value of N W/RT. Regular solution models for olivine are considered and the distribution curves for temperatures between 400 and 1400° C are drawn in Roozeboom figures.
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  • 29
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    Description / Table of Contents: Zusammenfassung Bereits vor der Intrusion des Leuchtenberger Granits waren seine Rahmen-gesteine unter den Bedingungen der Amphibolit-Fazies regionalmetamorph eingeformt worden, wobei sich folgende Paragenesen bildeten: Muscovit + Biotit + Granat ± Sillimanit ± Staurolith (+ Quarz + Plagioklas) Muscovit + Biotit ± Kalifeldspat (+ Quarz + Plagioklas). Die Kontaktmetamorphose führt in den äußeren Bereichen der Aureole zur Paragenese Muscovit + Andalusit + Cordierit + Biotit (+ Quarz + Plagioklas), die der Hornblende-Hornfels-Fazies entspricht. In der inneren Kontaktzone werden die p-t-Bedingungen einer höhergradierten Hornfelsfazies erreicht, die sich in der Paragenese ± Kalifeldspat + Sillimanit + Cordierit ± Almandin + Biotit (+ Quarz + Plagioklas) dokumentiert. Die zonale Anordnung der Mineral-Paragenesen im Kontakthof läßt sich durch quantitative Verbreitungskarten anschaulich machen (150 Modalanalysen aus 59 Fundpunkten). Phasenbeziehungen und Mineralreaktionen werden anhand von AKF- und AFM-Diagrammen diskutiert, für deren Aufstellung 19 Mineralanalysen neu ausgeführt wurden. Durch den Vergleich mit derzeit verfügbaren experimentellen Unterlagen lassen sich die p-t-Bedingungen im Steinacher Kontakthof abschätzen. Danach ist ein Druckbereich von 1,5–3 kbar am wahrscheinlichsten. Mit der Bildung der höchst-gradierten Hornfelse waren 550° C sicher überschritten, während nach dem Jaeger-Modell 700° C als alleroberste Temperaturgrenze anzusehen ist. In der innersten Kontaktzone muß man mit geringen O2-Partialdrucken rechnen.
    Notes: Abstract The southern margin of the Leuchtenberg granite massive is surrounded by a thermal aureole in which banded gneisses and mica schists have been transformed into hornfelses containing andalusite, sillimanite, cordierite, and almandine. Before the intrusion of the granite, the country rocks had undergone regional metamorphism to give mineral assemblages typical of the amphibolite facies: Muscovite + biotite ± K-feldspar + quartz + plagioclase in the banded gneisses and muscovite + biotite + garnet ± sillimanite ± staurolite + quartz + plagioclase in the mica schists. In the outer zone of the aureole, contact metamorphism produced the assemblage: Muscovite + andalusite + cordierite + biotite + quartz + plagioclase, corresponding to the hornblende-hornfels facies. In the inner zone of the aureole, increasing temperatures yielded the high grade assemblages: K-feldspar + sillimanite + cordierite ± almandine + biotite + quartz + plagioclase sillimanite + cordierite ± almandine + biotite + quartz + plagioclase. The zonal arrangement of the mineral assemblages within the Steinach aureole is shown in quantitative distribution maps of andalusite, contact-metamorphic sillimanite, cordierite, and contact-metamorphic garnet respectively, based on 150 modal analyses (from 59 points, Fig. 1). Andalusite (Fig. 10) reaches its maximum at about 200–400 m from the granite border and, toward it, is more and more substituted by sillimanite (Fig. 11). On the other hand, contact metamorphic sillimanite goes to the outer zone of the aureole almost as far as andalusite. This means that the sillimanite isograd passed across the andalusite zone during the contact metamorphism. Cordierite (Fig. 12) shows a constant increase from the margin to the innermost zone of the aureole, as does contact metamorphic garnet (Fig. 13). Phase relations and mineral reactions are discussed in terms of AKP- and APM-diagrams (Figs. 14, 15, 17, 18) based on 19 new mineral analyses (Tables 5–9). With respect to the experimental data so far available, possible P-T-conditions within the Steinach aureole have been discussed. The transition from the low to the high grade assemblages took place very near to the cross-over point of the andalusite/sillimanite equilibrium curve and the breakdown curve of muscovite + quartz in the P-T-diagram (Figs. 16, 19). This gives a minimum H2O-pressure of 1 kbar. In the innermost contact zone, temperatures must have exceeded 550° C, which is in good agreement with recent oxygen-isotope data as well as with Jaeger's model. As is shown by the ore mineral assemblages, studied in polished sections (Table 10), the oxygen activity in the high grade hornfelses was low.
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    Notes: Abstract The study of the problem of the black coloration of feldspathoids of the sodalitic group (nosean, haüyne, sodalite) reveals iron as a main factor. A statistical study of the global compositions of these minerals proves that their enriching in Fe is accompanied by a decrease in Al, but also by an increase in Si. A substitution of Fe+++ to Al in the structure in the feldspathoids is suggested. The analysis with an electron microprobe confirms this hypothesis and allows us to state a fondamental difference between the formation of miaskitic phonolites rich in Fe++ and that of agpaitic phonolites rich in Fe+++.
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  • 31
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    Notes: Abstract The pegmatites of Eastern Connecticut have a mineralogy consistent with a magmatic origin yet occur in a non-igneous environment. Various theories of genesis have been investigated by the Rb-Sr geochronologic method. Rb-Sr measurements on early stage pegmatite minerals indicate an age of 258±1 m.y. with initial Sr87/Sr86=0.734±0.0096. Previously reported K-Ar and U, Th-Pb ages for pegmatite minerals are 249±8 m.y. and 260±3 m.y. respectively. Rb-Sr whole rock data for the host rocks vary between 285±10 m.y. and 472±15 m.y. in age and between 0.705±002 and 0.7167±0.0016 in initial Sr87/Sr86. A direct genetic relationship between the pegmatites and their host rocks is thus precluded. In addition, whole rock samples of the Brimfield schist taken at variable distances from the Strickland Quarry pegmatite have remained essentially closed systems with respect to Rb and Sr and thus an in situ origin for this pegmatite is unlikely. Mixing of pegmatite and country rock systems has occurred only locally, and isotopic studies of these mixed rocks yield a date of 231±4 m.y. with initial Sr87/Sr86=0.7188±0.004, an age not inconsistent with previously reported K-Ar and Rb-Sr mineral dates on host rock minerals (approximately 220 to 240 m.y.). Late stage cleavelandites are anomalously enriched in radiogenic Sr-87, the source of which was most probably other zones within the crystallizing pegmatite. This is indicated by analyses of pegmatite whole rocks which show both enrichment and depletion of radiogenic Sr-87 in local systems. The conclusion is drawn that there was widespread movement of radiogenic Sr-87 within each pegmatite system, but that pegmatite-host rock reactions were minimal.
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    Description / Table of Contents: Résumé Des cristaux de grenat ont été découverts, situés sur les plans de fracture postérieurs à la solidification d'un dôme-coulée de trachyte pantelleritique du Volcan Fantale (Shoa, Ethiopie). Leurs propriétés physiques et leur composition, donnée par analyse à la microsonde ont permis de préciser qu'il s'agit d'Andradite. Ils peuvent être rapprochés par leur gisement et leur composition, des grenats décrits récemment à Menoyre (Cantal, France). La signification de leur origine fumerollienne est discutée.
    Notes: Abstract Garnets have been discovered, placed against fracture shelve surfaces posterior to the solidification of a trachy-pantelleritic dome-flow of the Fantale volcano (Shoa, Ethiopia). Their physical characteristics and their chemical composition, obtained by microprobe analysis allow us to lable them as andradite. By their habitus an their composition they can be related to the recently described garnets of Menoyre (Cantal, France). The meaning of their fumarolitic-origin is discussed.
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  • 33
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    Notes: Abstract The phase K2Mg5Si12O30 was synthesized both hydrothermally and dry under a variety of pressures and temperatures, and its stability relations were determined. Under hydrothermal conditions it exhibits a lower stability limit lying at 595°C, 1 kb, and 650°C, 2 kb, due to its breakdown into the hydrous assemblage quartz+KMg2.5Si4O10(OH)2 (a mica phase). Its upper temperature stability under hydrothermal conditions is given by its incongruent melting to MgSiO3+liquid. Near 820° C at a fluid pressure of approximately 6.5 kb the two univariant curves for these breakdown reactions intersect thus limiting the stability field to lower fluid pressures. — Under anhydrous conditions K2Mg5Si12O30 becomes unstable at pressures between approximately 7 and 32.5 kb due to its incongruent melting to the assemblage MgSiO3+quartz (or coesite)+liquid; this melting curve has a pronounced negative slope. No subsolidus breakdown assemblage was encountered at 32.5 kb down to temperatures as low as 750°C. This behavior is probably due to the instability of other ternary compounds in the system K2O-MgO-SiO2 at high pressures and thus to the existence of very low-temperature eutectics involving only binary and unary solid phases plus liquid. It is likely that these stability relations provide a model for those of the natural minerals merrihueite and roedderite which contain Na and Fe+2 partly substituting for K and Mg and which were encountered in several meteorites. Therefore, the cosmic events leading to the formation of these minerals must have taken place at relatively low pressures and high temperatures, especially when water was present. The bulk compositions of these minerals appear to be incompatible with average chondritic matter under equilibrium conditions. Hence merrihueite and roedderite are not likely to be found in equilibrated chondrites which contain feldspars instead.
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  • 34
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    Notes: Abstract The reaction chlorite+muscovite=staurolite+biotite+quartz+vapor has been experimentally determined and reversible equilibrium has been demonstrated. At an oxygen fugacity corresponding to that of the FMQ buffer and using a starting mixture with a Mg/Mg+Fe ratio of 0.4, the equilibrium conditions of the reaction are 565±15°C at 7 kb and 540±15°C at 4 kb. The preliminary maximum stability of staurolite in the presence of quartz, muscovite, and biotite has been established at the following conditions: 675±15°C at 5.5 kb and 575±15°C at 2 kb. The results of both investigations are in good agreement with other experimental data and with petrographical observations. Furthermore, equilibria between minerals in medium-grade pelitic rocks are deduced from theoretical considerations and the effect of T, P solid, $$P_{H_2 O}$$ , $$P_{O_2 }$$ on some dehydration reactions is discussed.
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    Notes: Abstract Different superstructures of wollastonite from the regional metamorphic Lepontine zone (Southern Alps) and other localities (e.g., Sierra Nevada, California) have been found. Besides well ordered normal 1T, 2M (2T ?), 4T-wollastonite, all disordered intermediate states exist. The various polymorphs were studied with the precession method. The superstructure is observed in reflections hkl k=odd. 4T-wollastonite is described with a 0=31.659 Å and is shown to be a common polymorph. The superstructure seems to be independent of metamorphic grade (in the well-zoned Lepontine area it does not follow any mineralogical isograds) and occurs only in strained rocks with well developed lineation and strong preferred orientation. Thus the formation of the superstructure is explained as a deformation effect. Contrary to temperature and pressure, both stress and strain show large local variations and inhomogeneities. Experimental deformation of a 2T-wollastonite at 4 kb and 700° C produced complete disorder. It is suggested that consecutive annealing of strained disordered wollastonite causes periodic stacking sequences of [SiO3]-chains along the a*-axis. It appears from these studies that superstructures in chainsilicates are more common than presently known and that they might be useful petrogenetic indicators for the deformation and cooling history of a rock.
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  • 36
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    Notes: Abstract Multivariate statistics — regression and principal components analysis are used to study the chemical data on 93 pairs of coexisting biotite and garnet. The dependence of the distribution coefficient on compositional variables both in garnet and biotite is demonstrated by regression analysis. The use of eigenvalues and eigenvectors is made to obtain values of transformed distribution coefficients which are found to be significant in distinguishing among rocks formed at different pressure and temperature.
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  • 37
    ISSN: 1432-0967
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    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung An 120 Sedimentproben aus dem Bodensee wurde der Tonmineralbestand der Fraktion 〈2μ durch die röntgenographische Phasenanalyse halbquantitativ ermittelt. Glimmer, Smectit und Chlorit sind die charakteristischen Tonmineralgruppen in den Sedimenten. Mixed-layer-Minerale treten so gut wie nicht auf, Kandite konnten nicht nachgewiesen werden. Aus der Bestimmung der relativen Häufigkeit von Glimmer und Smectit ergibt sich, daß das Smectit/Glimmer-Verhältnis von Osten (Einmündung des Alpenrheins) nach Westen ständig zunimmt. Diese Verteilung ist durch die Zufuhr von Glimmer und Chlorit durch den Alpenrhein aus den nördlichen Alpen bedingt, die jedoch mit zunehmender Entfernung vom Delta durch die Molasse-Distributiv-Provinz mit vorherrschend Glimmer und Smectit überlagert wird.
    Notes: Abstract Mica, smectite, and chlorite are the characteristic clay minerals in about 120 Recent sediment samples of Lake Constance as shown by semiquantitative clay mineral analysis. Interstratified clay minerals are practically absent, kandites were not found. The decrease of the smectite/mica ratio from West to East is apparently due to the dominance of the mica-chlorite assemblage of the Rhine river derived from the northern Alps in the eastern part of the lake. With increasing distance from the delta of the Rhine river, the Tertiary Molasse clay minerals (mainly mica and smectite) derived from rocks surrounding the lake become more abundant.
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  • 38
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    Notes: Abstract Available data on the stability of amphibolites and the basalt-eclogite transition allow an estimate of the stability field of eclogites in wet systems. It appears that if water and load pressures are comparable, eclogites cannot be stable in the crust; the formation of eclogites in the crust requires moderate total pressures and low water pressures. If the reactions forming eclogites occur in essentially dry rocks, their formation may reflect kinetic as well as equilibrium factors.
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  • 39
    ISSN: 1432-0967
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    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Zur Bestimmung der δO18-Werte von Sulfaten wird BaSO4 mit Kohlenstoff reduziert und das gewonnene CO2 massenspektrometrisch gemessen. Das sehr einfache Reduktionsverfahren erlaubt eine Meßgenauigkeit von 0,4‰ relativ zur SMOW-Skala. Eine kombinierte Schwefel- und Sauerstoffisotopenanalyse von Gips bzw. Anhydrit sollte Einzelheiten über Entstehung und Herkunft dieser Sulfate erkennen lassen. Am Beispiel eines Kupferschieferprofiles wird gezeigt, daß durch eine derartige Analyse primäre Restsulfate von sekundär zu Sulfaten aufoxidierten Sulfiden unterschieden werden können. Die sekundären Sulfate sind durch relativ leichten Sauerstoff (δO18=+4‰)gekennzeichnet und an S34 verarmt (δS34≥−23‰), was auf den Zusammenhang mit den durch bakterielle Reduktion gebildeten Kupferschiefersulfiden schließen läßt (Einzelheiten vgl. Marowsky, 1969). Die primären Restsulfate sind dagegen an O18 und S34 angereichert. Die von Lloyd (1968) gefundene Korrelation zwischen der Anreicherung von schwerem Schwefel und schwerem Sauerstoff in dem verbleibenden Sulfat bei bakterieller Sulfatreduktion konnte bestätigt werden.
    Notes: Abstract The oxygen isotopic composition of sulfates has been determined in CO2 by mass spectrometry after reduction of BaSO4 with carbon. The experimental procedure with a precision of 0.4‰ in the scale relative to SMOW is described in some detail. It is a problem to distinguish between primary and secondary gypsum or anhydrite in argillaceous sediments. A combined analysis of sulfur and oxygen of the sulfates mentioned is applied for getting evidence on the origin of these sulfates. Samples of a Permian Kupferschiefer profile show that primary residual sulfates from closed systems can be distinguished from secondary sulfates formed from oxidized sulfides. These secondary sulfates are characterized by relatively light oxygen (δO18≈+4‰ relative to SMOW) and sulfur (δS34≧-23‰), which is due to their origin from sulfides of bacterially reduced sulfates. The primary residual sulfates are enriched in O18 and S34. The correlation of heavy sulfur with heavy oxygen during bacterial reduction of sulfates (Lloyd, 1968) could be confirmed.
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  • 40
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    Notes: Abstract Synnneusis is the process of drifting-together and mutual attachment of crystals suspended in a melt. This process is episodic, is most characteristic of the earlier stages of consolidation, and appears to be related to magmatic turbulence. Union of crystals in synneusis relation normally occurs on their broader faces in preferred orientations which coincide with positions of low interfacial energy. Quantitative studies of several common igneous minerals indicate that crystals of a single mineral characteristically show a strong affinity for synneusis and typically unite in parallel or twinned orientation. Some pairs of unlike minerals join readily in synneusis relation, but most appear to be antipathetic. Synneusis structures have generally been overlooked or misinterpreted as epitaxial intergrowths, primary twins, irregular growth forms, or the random union of crystals which have grown into contact. These possibilities must be rejected where it can be shown that two or more distinct crystals are involved, that they were relatively large when they came in contact, and that they are oriented with prominent faces in common. Synneusis is responsible for three major features of the magmatic fabric: (1) the small scale segregation of minerals; (2) the systematic mutual orientation of adjacent crystals in synneusis relation; and (3) the morphology of their common boundary. Because synneusis structures are restricted to igneous rocks and are widespread and easily recognized, they provide a definitive and ready criterion of magmatic origin.
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  • 41
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    Notes: Abstract The geochemistry of Chilean ignimbrites is discussed in terms of major and trace elements. The variation in the major elements and in the distribution of Ba, Co, Cu, Ga, Pb, Sn, Sr, V, and Zr with the “differentiation factor (1/3Si+K)-(Ca+Mg)” has been studied. The general trend is that characteristic of calc-alkaline rhyolite-dacite-andesite associations. Exceptionally high values of copper reported and high values of Sn and Zr provide further evidence of the anatectic origin of these ignimbrites.
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  • 42
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    Notes: Abstract A mixed-layer paragonite/phengite from low-grade metamorphic slates is described, showing strong tendency to regular mixed-layering with a paragonite/phengite ratio of about 6∶4. It is suggested that the mixed-layer paragonite/phengite is an intermediate phase in the formation of paragonite from Na-bearing illite or montmorillonite.
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  • 43
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  • 44
    ISSN: 1432-0967
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    Topics: Geosciences
    Notes: Abstract This report is a petrographic study of alteration phenomena in an area of 100 km2 in the Coastal Range west of Santiago. The stratified sequence of the area is of Cretaceous age and belongs to the western monoclinal limb of the Andean Geosyncline. Two structural units are present, separated by an angular unconformity. The older is about 9,000 m thick, and the younger 300 m thick. The rock types are mostly altered andesitic flows and flow breccias, and keratophyric ignimbrites and lavas, with alternating marine, brackish-water and terrestrial interbeds. Stratified rocks are cut locally by acid and basic apophyses and dikes, probably feeders of their volcanic host rocks. Discordant Cretaceous granitic plutons intrude the older unit. Throughout the whole stratigraphic section there are alteration minerals, which selectively replace the primary minerals, or fill amygdules and open fractures, or form a cement in flows, dikes and sedimentary interbeds. Patterns of alteration are regular and persistent; they correlate on a large scale with stratigraphic level and on a smaller scale with position within each individual flow and situation within amygdules. The stratigraphically controlled pattern is as follows: $$\begin{gathered} 1.{\text{ Younger unit}}{\text{.}} \hfill \\ {\text{ }}\left. \begin{gathered} {\text{Lower portion: 30m: albite}}---{\text{pistacite}}---{\text{actinolite}}---{\text{chlorite}}---{\text{ }} \hfill \\ {\text{calcite}}---{\text{sphene}}---{\text{quartz}} \hfill \\ \end{gathered} \right\}{\text{greenschist facies}} \hfill \\ {\text{2}}{\text{. Older unit}}{\text{.}} \hfill \\ {\text{ }}\left. \begin{gathered} {\text{a) 0}}---{\text{1,280 m : albite}}---{\text{pumpellyite}}---{\text{prehnite}}---{\text{calcite}}---{\text{chlorite}}---{\text{ }} \hfill \\ {\text{ laumontite}} \hfill \\ {\text{b) 1,280}}---{\text{4,850 m: albite}}---{\text{adularia}}---{\text{calcite}}---{\text{prehnite}}---{\text{pumpellyite}}--- \hfill \\ {\text{pistacite}}---{\text{white mica}}---{\text{quartz}} \hfill \\ {\text{c) 4,850}}---{\text{8,110 m: albite}}---{\text{pistacite}}---{\text{quartz}}---{\text{chlorite}}---{\text{calcite}}--- \hfill \\ {\text{white mica}}---{\text{sphene}}---{\text{adularia prehnite}}---{\text{pumpellyite}} \hfill \\ \end{gathered} \right\}{\text{prehnite}}---{\text{pumpellyite facies}} \hfill \\ {\text{ d) 8,110}}---{\text{9,060 m: albite}}---{\text{pistacite}}---{\text{actinolite}}---{\text{sphene}}---{\text{calcite \} greenschist facies}} \hfill \\ \end{gathered} $$ The pattern of alteration in the older unit is comparable to that described for burial metamorphosed sequences in New Zealand and Australia. Reappearence of the greenschist facies at a higher level in the younger unit poses a problem for which several explanations are possible. The smaller scale pattern of alteration shows a persistent tendency —not without exception — for the “grade” of the alteration assemblage (as correlated with depth on the large scale) to increase: from the base of the flow (non-amygdaloidal part) upward (amygdaloidal part), and from the rim of each amygdule inward. Also recognizable on the scale of a single flow is a tendency for upward increase in: a) extent of alteration (the basal zone may be fresh andesite), and b) weight percent of Na2O, K2O (with complementary depletion in CaO), and of Fe2O3/FeO. Preliminary observations indicate that this alteration pattern persists for at least 400 km north of the area here described in rocks of similar lithology and age. It is unrelated to local granitic plutons.
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  • 45
    ISSN: 1432-0967
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    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung Zwei von den Verfassern neu aufgefundene Vorkommen von Stilpnomelan in Gesteinen der Prasinit-Phyllit-Serie der Grünschieferzone der Münchberger Gneismasse (NO-Bayern) werden beschrieben und Angaben zur röntgenographischen Identifizierung sowie zum Gesteins- und Mineralchemismus mitgeteilt. Die Stilpnomelanbildung wird in das metamorphe Geschehen des Gesteinskomplexes zeitlich eingeordnet und mit den Mineralneubildungen im Grenzbereich Grünschiefer-Serpentinit verglichen; die dafür auftretenden wahrscheinlichen Druck- und Temperaturbedingungen werden kurz diskutiert.
    Notes: Abstract Two new occurrences of stilpnomelane found by the authors in the Prasinite-Phyllite series of the “Grünschieferzone” of the “Münchberger Gneismasse” (Northern Bavaria) will be described and information on the x-ray identification as well as on rock- and mineralchemistry will be offered. The crystallization of stilpnomelane will be located chronologically in the metamorphic history of the rock complexes and compared with the recrystalization of other minerals in the border range of the Greenslate-Serpentin rocks; the possible pressure and temperature conditions will be discussed briefly.
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  • 46
    ISSN: 1432-0967
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    Notes: Abstract In the middle part of the Cévennes, situated at the south-eastern border of the Massif Central, there are outcrops of micaschists, gneisses and granites in which the increase of metamorphic grade was investigated along the river Beaume. This paper presents the results of the petrographic-geochemical analysis of the micaschists of the greenschist facies. Chemical analyses of the micaschist-samples examined petrographically show their nearly constant composition, a fact which e.g., is expressed by similar CaO/Na2O- and MgO/FeO-proportions. As the average values of the determined oxides approach the respective average values of analyses of graywackes recorded by Pettijohn (1957) the original sediment is likely to have been an argillaceous graywacke deficient in calcite. In enrichments of the phyllosilicates pyrophyllite was detected by X-ray diffraction; its amount is about 2 to 5 weight percent of the rocks. With increasing metamorphic grade the following parageneses were found in the metamorphic zones of the greenschist facies: Zone Ia: Quartz+chlorite+pyrophyllite+muscovite+clinozoisite. Zone Ib: Quartz+chlorite+pyrophyllite+muscovite+biotite+clinozoisite. The absence of biotite in Zone Ia, though the chemism of the rocks is practically the same, is obviously due to the different Al2O3-content of the chlorites of Zones Ia and Ib. The chlorite of Zone Ia is more deficient in Al2O3 than the one of Zone Ib. With passage from Zone Ia to Zone Ib the position of the tie line between chlorite and muscovite in the ACF-A'FK-diagram changes in such a way that in Zone Ia, because of purely chemical reasons, biotite cannot occur as coexisting mineral. The beginning of Zone II is characterized by the occurence of almandine, rich in spessartine. The following paragenesis is typical of this zone: Quartz+chlorite+pyrophyllite +muscovite+biotite+almandine+clinozoisite. Additionally the micaschists of these three zones display albite, the greater part of which is concentrated in mm-thin layers with associated minor amounts of quartz and micas. Paragonite whose formation by reaction between albite and pyrophyllite is to be expected based on experimental results (Winkler, 1967, p. 95) could not be proved by X-ray diffraction. In Zone III andalusite occurs instead of pyrophyllite. Furthermore, as chlorite and clinozoisite are absent and oligoclase occurs for the first time this zone is regarded as the first subfacies of the almandine-amphibolite-facies. The chemism and the observed mineral parageneses of the subfacies of the almandine-amphibolite-facies will be treated in a separate publication.
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  • 47
    ISSN: 1432-0967
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    Topics: Geosciences
    Notes: Abstract During alkali metasomatism of the country-rock associated with ijolite-carbonatite complexes the development of sodic amphibole and/or pyroxene is characteristic. In this paper, some new chemical analyses of these minerals, together with published analyses from fenites of Kenya, Uganda and Tanzania, include those of co-existing pairs of amphibole and pyroxene. The common amphiboles of the fenites are magnesioarfvedsonites with 100 Mg: Mg+Fe+Mn ranging from 67 to 36. They co-exist with aegirines having 0.75 to 0.89 ions Fe+3. Most of these minerals are poor in Ca; co-existing pairs tend to show corresponding increases in Ca and in Fe+2. In the syenitic fenites of Tororo and Budeda, considered to have formed at higher temperatures, the stable mineral is aegirine-augite. New analyses of richterite, magnesioarfvedsonite and aegirine from carbonate-rich rocks are also presented, and the relation between fenites and carbonatites is discussed.
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  • 48
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    Notes: Abstract The petrogenesis of Franciscan-type blueschists is controversial or paradoxial in regard to the possible significance of the serpentinite-blueschist association, the isochemical vs. allochemical character of blueschist metamorphism, the significance of “high pressure” mineralogy, and the physical-geologic-tectonic conditions existing during metamorphism. A model for blueschist alteration during serpentinization is presented that departs from conventional treatments of metamorphism because the reaction path rather then the thermodynamically lowest energy state is considered to be a controlling factor. Alteration of ultramafic rocks to serpentinites requires oxidation of iron in the rock and selective withdrawal of water from saline pore fluids derived from surrounding eugeosynclinal rocks. Pore fluids become concentrated and chemically reducing in the vicinity of serpentinites. The activated pore fluids may react with surrounding rocks via reactions that include a reduction step. The pore fluids may also affect the reaction path through surface chemical effects existing between mineral surfaces and/or “growth units” and the reducing pore fluid. The degree of polarization of oxygen ions in the silicate structural types, a function of polymerization and aluminum substitution, may control the surface effects and result in the preferential growth of chain silicates, and, more generally, of silicates with low amounts of tetrahedral aluminum. The ratio Mg+2/H+ in the pore fluid can change during serpentinization depending on the extent to which magnesium is lost from the original mafic rock. This ratio may be an important control on the growth of jadeite vs. glaucophane in the presence of excess quartz. The reduction reactions and those involving conventional fluid-solid equilibria cause a change in pore fluid chemistry as the reaction proceeds. Such reactions may explain short-range metasomatic transitions observed in some blueschists. The kinetic controls involving surface chemical effects are catalytic and may explain isochemical phenomena. The ultimate “drive” for the process is the large negative free energy change of serpentinization that results when ultramafic rocks are emplaced in eugeosynclinal rocks with which they are not in equilibrium. Removal of this overwhelming disequilibrium may induce secondary disequilibrium and activation of pore fluids, producing Franciscan-type blueschists.
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  • 49
    ISSN: 1432-0967
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    Topics: Geosciences
    Notes: Abstract Chemical and mineralogical analyses of the clay fraction of eleven soils containing a large amount of vermiculite clay and representing a wide range of parent materials revealed that two types of vermiculite clays exist: (1) An aluminous type in which Al3+ substitutes for Si4+ in tetrahedral positions in the same order of magnitude as in the coarse grained vermiculites and micas, and with Al3+ as the dominant octahedral ion. (2) A silicious type in which only Si4+ occupies the tetrahedral positions, and with Fe3+ and Mg2+ as the dominant octahedral ions. The aluminous vermiculite clay was found to occur in soils derived from acid igneous rocks and is usally associated with mica, whereas the silicious type was found to occur in soils derived from basic igneous rocks which do not contain mica. Because of this close association of these two types to their parent material, it was concluded that the aluminous vermiculite is a product of alteration of mica whereas the silicious type is a product of synthesis from primary oxides of silica, alumina, iron, and magnesium. Both types of vermiculite clays tend to be dioctahedral in contrast to the trioctahedral nature of the coarse-grained vermiculite.
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  • 50
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    Notes: Abstract The trace element contents of 23 sphalerites and galenas from Binnatal, Switzerland, have been determined. Most of these samples have been previously studied in respect to lead and sulphur isotope abundances. Coloration of sphalerites — varying from yellow to black for nearly identical iron contents — seems to be strongly influenced by the manganese content. A linear relationship between sulphur isotope composition and copper content in sphalerites was found. Trace elements in galenas show a significant inverse relationship between silver and copper. With the determination of the bismuth content, it is possible to distinguish several galena types; a similar grouping has been found by lead isotope determinations. The results of the trace analyses are discussed in connection with the occurrence of a large number of very rare and special Pb-As-sulphosalt minerals in the Binnatal dolomites.
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    Notes: Abstract A petrogenetic grid is constructed for mineral assemblages occurring in metapelitic rocks, particularly those involved in the paragenesis of cordierite. The most useful assemblages for estimating pressures and temperatures are staurolite-cordierite, cordierite-biotite-Al2SiO5 and cordierite-hypersthene. Cordierite is stable with kyanite, sillimanite or andalusite. At high pressures cordierite is Mg-rich so that pelitic rocks typically do not contain the phase. Cordierite is stable at temperatures less than 500° C but does not commonly appear in metapelitic rocks until the garnet-chlorite, chlorite-staurolite or chlorite-Al2SiO5 tie-lines are broken. At high metamorphic grades, the assemblage garnet-hypersthene-cordierite indicates relatively low pressures, and the assemblage hypersthene-cordierite-sillimanite relatively high pressures. It is clear however, that the absence of cordierite is of little use in characterizing a metamorphic facies unless an alternate mineral assemblage can be shown to be more stable.
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  • 53
    ISSN: 1432-1041
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Zusammenfassung 3H-g-Strophanthin wurde Patienten folgender drei Kategorien i.v. verabreicht: a) Kontrollpatienten b) Patienten mit eingeschränkter Leberfunktion (Cirrhose, Verschlußikterus) c) Patienten mit eingeschrankter Nierenfunktion (Pyelonephritis, Glomerulonephritis).. Bei den Kontrollpatienten nahm der Serumspiegel mit zwei Zeitkonstanten ab (t 1/2 20 min bzw. etwa 50 Std). 5–6 Std nach der Injektion betrug die Serumkonzentration nur noch 10% des Ausgangswertes. Nach 48 Std waxen etwa 61% der verabreichten Dosis mit dem Urin ausgeschieden worden. 3H-g-Strophanthin wurde in unveranderter Form eliminiert. Bei Leberkranken mit eingeschrankter Galleproduktion zeigte der zeitliche Verlauf des Serumspiegels und die Urinausscheidung dasselbe Verhalten wie bei den Kontrollpatienten. Von den nierenerkrankten Patienten dagegen worden in 48 Std nur 28% des verabreichten 3H-g-Strophanthin mit dem Urin ausgeschieden. Die Serumradioaktivität lag 6–48 Std nach der Injektion des Glykosids 2–3 mal so hoch wie bei den Kontrollen.
    Notes: Summary 3H-ouabain was administered intravenously to control patients, and to patients suffering from liver disease or renal failure. In the control patients the 3H-ouabain disappeared from the serum by two exponentials, with half-lives of about 20 min and 50 h, respectively. After 5–6 h only 8% of the initial serum concentration remained. During 48 h following drug administration about 61 % of the administered dose was excreted in the urine. 3H-ouabain was excreted as such and not metabolized. Liver disease accompanied by pathological impairment of bile production neither affected the disappearance from the serum nor the urinary excretion. During renal failure, however, only 28% of the administered 3H-ouabain was excreted with the urine during 48h. The serum level was 2–3 times higher than in the control patients.
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  • 54
    ISSN: 1432-1041
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In nine subjects representing a majority (75 percent) of the population tested, ten milligrams of Dexoxadrol combined with 600 mg of acetylsalicylic acid (ASA) was essentially equivalent to 20 or 30 mg of Dexoxadrol pooled sample when tested by ischemic arm method, both doses being significantly more potent than ASA alone one hour after dosage. Three hours after dosage, all doses of Dexoxadrol were still significantly above ASA alone or lactose placebo indicating a more prolonged action of this drug. The stimulating effect of lactose placebo is postulated to explain the temporary rise (1 h) noted by use of this substance. When all twelve subjects are considered, because of three negative reactors, only statistically significant differences between ten milligrams of Dexoxadrol plus 600 mg of ASA are distinguishable from ASA alone or placebo at the end of one hour. At all dosage levels some side effects similar to alcohol were noted, numbness, dizziness, drowsiness, etc., as described by (LASAGNA and PEARSON, 1965). The 30 and 20 mg dosage produced more prominent psychic effects, while the 10 mg dosage with ASA produced a minimum of such effects and was virtually as effective as the higher dosage in nine of twelve subjects.
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  • 55
    ISSN: 1432-1041
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Zusammenfassung An je 10 männlichen Versuchsper sonen wurde der Einfluß von 10 mg Diazepam (Valium®) und 50 mg Chlordiazepoxyd (Librium®) auf die Atmung untersucht. Dabei wurden Atemvolumen and alveolare CO2-Drucke bei Atmung von Zimmerluft und von 3 CO2-Luftgemischen (2.5%, 4% and 5.5% Vol CO2-Gehalt) gemessen und anhand von CO2-Atmungskurven ausgewertet. An weiteren je 10 Patienten mit fortgeschrittenem Lungenemphysem and Cor pulmonale wurde der Einfluß derselben Pharmaka anhand des zeitlichen Verhaltens der arteriellen Blutgase (pH, PCO2, PO2 and Standardbicarbonat) unter Berücksichtigung der pharmakologischen Schlafwirkung studiert. — Dabei fanden sich folgende Ergebnisse : 1. Weder bei Luftatmung noch bei CO2-Atmung ließen sich nach Diazepam und Chlordiazepoxyd auffällige Unterschiede in Atemfrequenz, Atemzugvolumen und Atemminutenvolumen bei herz- und lungengesunden Normalpersonen nachweisen. Die alveolaren CO2-Drucke blieben bei Luft- und CO2-Atmung im Mittel unbeeinflußt. — 2. Bei Patienten mit Lungenemphysem und manifester Hyperkapnie kam es nach Diazepam mit Einsetzen der Schlafwirkung zu einem signifikanten mittleren PCO2-Anstieg von 3 Torr, nach Chlordiazepoxyd im Mittel von 2 Torr mit entsprechender pH-Senkung von 13/1000 (Diazepam) und 1/100 (Chlordiazepoxyd). Nach Diazepam klang der hypoventilative Effekt nach 30 bis 45′, nach Chlordiazepoxyd nach 60 bis 75′ wieder ab. —3. Diese Veränderungen entsprechen der physiologisehen Schlafwirkung. Demzufolge 1st eine primäre (pharmakologische) Empfindlichkeitsänderung des Atemzentrums bei den angegebenen Dosierungen unwahrscheinlich. — 4. Die Auswirkungen einer zusätzlichen Relaxation der Atem muskulatur beim Emphysemkranken nach Gabe von Diazepam wird anhand der vorliegenden Literatur besprochen. —Vor der Gabe von Benzodiazepinen bei Patienten mit fortgesehrittenem Emphysem wird die blutgasanalytische Überprüfung der Atemfunktion angeraten und bei Fallen mit manifester Hyperkapnie eine zurückhaltende Dosierung empfohlen.
    Notes: Summary The influence of 10 mg Diazepam (Valium®) and 50 mg Chlordiazepoxyd (Librium®) on the respiration was studied in 10 healthy probands and 10 patients with emphysema of the lung. In the study of healthy persons the specific ventilation and the alveolar CO2 during the breathing of room-air and 3 different CO2-air-gasmixtures (2.5%, 4.0% and 5.5% Vol CO2-content) were measured and CO2-response-curves constructed. The influence of the same drugs was studied in 10 patients with advanced pulmonary emphysema and Cor pulmonale. In these patients the changes of the arterial blood-gases (pH, PCO2, PO2 and Standard bicarbonate) were determined over different periods of time. — Results: 1. After administration of the drugs in healthy persons no difference was seen in respiratory frequency, tidal volume and minute volume while breathing room-air and the different CO2-air-gas-mixtures. The mean of the alveolar PCO2 during room-air-and CO2-breathing were not altered. — 2. In patients with pulmonary emphysema and hypercapnia an increase of the mean PCO2 of 3 torr was seen shortly after the administration of Diazepam when the patients started to sleep. After Chlordiazepoxyd an increase of 2 torr in the mean PCO2 was seen. Corresponding a decrease in pH (13/1000 after Diazepam; 1/100 after Chlordiazepoxyd) was seen. This effect was abolished 30–45′ after the injection of Diazepam and 60–75′ after Chlordiazepoxyd. — 3. These changes equal the respiratory-patterns during sleep. It is the conclusion that there is no pharmacologically induced change in the sensitivity of the respiratory center in the used dosages of these drugs. — 4. The effects of a possible added relaxation of the respiratory muscles in patients with pulmonary emphysema after administration, of Diazepam is discussed. — In patients with pulmonary emphysema blood-gas-studies should be done prior to the administration of Benzodiazepines. They can be tried in patients with obvious hypercapnia cautiously, but especially in the case of Diazepam 10 mg/dosis should not be exceeded.
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  • 56
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    ISSN: 1432-1041
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
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  • 57
    ISSN: 1432-1041
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A double-blind multicentre investigation has been set up in patients with angina pectoris to compare the activity of a beta-blocker (Ciba 39'089-Ba, Trasicor) with a placebo. Further, a follow-up study of the clinical effects after long-term treatment was carried out. — As criteria of evaluation the following were considered: number and severity of anginal attacks, consumption of nitroglycerin pills, physical condition, and performance. At the end of the trial the patients were asked to state which drug they preferred. The patients were checked for body weight, blood pressure, heart rate, ECG and side-effects. The data obtained on 62 patients were evaluated statistically. The analysis proved that Trasicor is more effective than the placebo in reducing the number of anginal attacks and the consumption of nitroglycerin pills, and is more effective in improving physical performance. No change was noticed in body weight but the heart rate and systolic blood pressure decreased with the drug. — Only mild side-effects were reported in a small number of patients. — A clear-cut reduction or total remission of anginal attacks and diminished nitroglycerin consumption were observed during the long-term study.
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  • 58
    ISSN: 1432-1041
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Twenty patients with neurocirculatory asthenia (NCA) have been investigated. They suffered from at least three out of seven defined symptoms and the severity of the symptoms prevented an ordinary daily activity. The patients were classified according to physiological variables and psychiatric (interview) criteria. They were treated with Aptin®, an adrenergic beta-blocking agent, and placebo in a double-blind cross-over design. From objective and subjective assessment of symptomatic improvement and drug preference, eight patients were classified as Aptin-responders and eleven as placebo responders. Physiological characteristics of hyperkinetic circulation due to increased activity of the sympathetic nerves was found in seven Aptin-responders but only in four placebo-responders. Six Aptin-responders were classified as anxiety states but only four placebo-responders. — The trial illustrates how therapy with a specific drug can reveal differences of probably etiological character in patients constituting a symptomatic entity. Adrenergic beta-blocking therapy in NCA seems to be of value predominately in patients with signs of hyperkinetic circulation and/or anxiety states.
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  • 59
    ISSN: 1432-1041
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    Topics: Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Zusammenfassung Mittels einer relativ einfachen Bestimmungsmethodik läßt sich die Elimination von intravenös infundiertem Tromethamin messen. Dabei wurden in 72 Std bei acidotisch exsikkierten Kindern insgesamt nur 58.2 ± 12.8% unverändert ausgeschieden. Eine Kumulation bei wiederholter Gabe ist daher möglich. Weitere Untersuchungen sind erforderlich, um die Elimination von intravenös infundiertem Tromethamin unter klinischen Bedingungen zu bestimmen.
    Notes: Summary Renal excretion of tromethamine after intravenous infusion is measured with a relatively simple method. The amount excreted within 24 h in 15 acidotic, exsiccated children was only 29.78 ± 9.40% and after 72 h five children had excreted 58.20 ± 12.80 %. Repeated applications of tromethamine therefore may lead to accumulation. Further examinations are necessary to determine the renal and extrarenal elimination of intravenously infused tromethamine under clinical conditions.
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  • 60
    ISSN: 1432-1041
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Zusammenfassung Es wurde demonstriert, daß in allen untersuchten Testsystemen α2-Makroglobulin die Fibrinolysehemmwirkung der bisher verwendeten synthetischen Antifibrinolytika verstärkt, dem Sofortantiplasmin des Plasmas also eine kräftige, bisher nicht gewürdigte Mitwirkung bei der medikamentösen Fibrinolysehemmung zukommt. Ob α2-Makroglobulin die einzige Substanz ist, welche die medikamentöse Antifibrinolytikawirkung im Plasma mit beeinflußt, ist damit nicht abgeklärt. — Es erscheint nach unseren Analyseergebnissen möglich, daß dysproteinämische Zustände den zu erwartenden Wirkungsgrad der bisher therapeutisch einsetzbaren Fibrinolysehemmer verändern.
    Notes: Summary We were able to show that in all systems tested α2-macroglobulin increases the inhibitory action of all of the synthetic antifibrinolysins used. It has, in addition to the immediate antiplasmin of plasma, an intense effect that has not been recognized before on the drug-induced inhibition of fibrinolysin. Whether α2-macroglobulin is the only substance effecting the drug-induced antifibrinolytic in plasma remains to be explained. From our results it seems possible that dysproteinemic states change the intensity of effect which one expects of the fibrinolytic inhibitors used therapeutically to date.
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  • 61
    ISSN: 1432-1041
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Case histories of five patients are presented who developed severe postural hypotension after being treated with guanacline. The postural hypotension did not develop until treatment had been given for 3–4 months and has persisted following withdrawal of guanacline for 12–15 months. It is suggested that this drug causes irreversible depletion of noradrenaline stores in adrenergic nerve terminals in some patients.
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  • 62
    ISSN: 1432-1041
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The hydrolysis of benzoylcholine, 0.05 mM, butyrylcholine, 10 mM, and suxamethonium, 0.025 mM, by the plasma of 10 subjects who developed prolonged apnoea following suxamethonium administered during anaesthesia, were measured. Plasmas from all available relatives in four families were similarly studied. The plasma of 3 subjects contained only atypical cholinesterase and hydrolysed suxamethonium, relative to butyrylcholine, at a rate of only 1.6% of that seen with usual human cholinesterase. One subject appeared to have only atypical cholinesterase on the basis of dibucaine and fluoride numbers. Suxamethonium hydrolysis, however, was sixteen times greater than that for the 3 homozygous atypical subjects. Family studies and inhibition of butrylcholine hydrolysis by decamethonium established that this subject was heterozygous with about 20% of the total cholinesterase in the usual form. Two other subjects were also heterozygous for usual and either atypical or fluoride resistant genes. One of them hydrolysed suxamethonium at 25% of the usual rate, but the other had a normal rate of suxamethonium hydrolysis. Four subjects had no detectable anomaly of plasma cholinesterase, and hydrolysed suxamethonium normally. The apparent affinity of suxamethonium for usual and atypical cholinesterase was also determined and the significance of measurements of the hydrolysis of suxamethonium in relation to prolonged apnoea produced by the drug is discussed.
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  • 63
    ISSN: 1432-1041
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    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The nicotinic acid ester, pentaerythritol-tetranicotinate orally administered in a dose of 1 g produced a moderate but sustained level (≈ 1 μg/ml) of free nicotinic acid in plasma. The concentration of esterbound nicotinic acid increased in plasma too. The increased nicotinic acid concentration in plasma was accompanied by a significant and protracted increase of the blood-flow of the forearm and hand and a decrease of the FFA-content of plasma. A weak flush of the face and the upper part of the body occurred as long as the nicotinic acid concentration of plasma was increasing. Repeated doses of pentaerythritoltetranicotinate at short intervals (30 min) produced a larger increase of the nicotinic acid concentration in plasma but the pharmacological effects did not increase. This was in agreement with earlier results that already a plasma concentration of 0.3–0.4 μg/ml of nicotinic acid produced almost maximum pharmacological effects. Only the effect on the blood-flow of the forearm was significantly greater when the nicotinic acid dose and nicotinic acid level of plasma was further raised. It was calculated that 1 g pentaerythritoltetranicotinate produced a plasma level of nicotinic acid and pharmacological effects similar to those produced by a continous i.v. infusion of nicotinic acid in a dose of about 0.02 mg/kg/min for 6–7 h.
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  • 64
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    Archives of microbiology 64 (1969), S. 215-222 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The Clark oxygen electrode was used to measure the microbial oxidation of hydrocarbons using preparations of resting cell suspensions. A strain of Corynebacterium sp. (7E1C) which utilized n-octane as sole carbon and energy source was examined for its ability to oxidize a variety of hydrocarbon substrates. The oxidation by resting cells exhibited an optimal temperature of 30° and an optimal pH range of 7.0–7.6. 1-Octanol, octanal, and octanoic acid were oxidized at rates comparable to n-octane. With the exception of n-decane, n-alkanes from pentane through heptadecane were attacked with a progressive increase in specific activity up the homologous series to n-octane, followed by a decrease as the hydrocarbon chain became progressively longer. n-Alkenes and halogenated n-alkanes substituted in the one position were oxidized at appreciably lower rates than the corresponding n-alkanes. Iso-Alkanes, cyclo-alkanes and aromatic hydrocarbons were relatively unsusceptible to oxidative attack.
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  • 65
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    Archives of microbiology 64 (1969), S. 357-368 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Descriptive notes on morphological variations are given for these species of Phlyctochytrium in Iceland: P. biporosum, P. bullatum, P., equale, P. hallii, P. irregulare, P. indicum, and P. mucronatum. A Phlyctochytrium with urn-shaped sporangia possessing large discharge pores is described but is not named. Sporangial shape in this plant is nearly identical to that of Phlyctidium marinum, a Rhizophydium sp. reported by Sparrow and Koch, and two species of Chytriomyces. A second unnamed species resembling P. longicollum but having a more distinctive sporangium and a large apophysis, is reported from pine pollen.
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  • 66
    ISSN: 1432-072X
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Es wird über eine Methode berichtet, an extrem dünnen Holzfolien die Abbauleistungen von Bodenpilzen zu messen. Aus einer Gesamtzahl von 280 geprüften Pilzarten wurden bei 27 mikroskopischen Pilzen mit hoher Aktivität Gewichtsabnahme und Reißfestigkeit von Ahornholz bestimmt. An Weizenstroh wurde mit einer Auswahl leistungsfähiger Pilze die Verminderung des Lignin- und Cellulosegehalts untersucht. Nach 120 Bebrütungstagen lag die Abnahme für Lignin zwischen 31 und 52%, für Cellulose zwischen 33 und 66%. Von den untersuchten Pilzen zeichneten sich Mammaria echinobotryoides, Hormiactis candida und Chaetomium piluliferum durch eine besonders starke Phenolproduktion aus. Die für alle geprüften Pilze mehr oder weniger typische Phenolproduktion stand in enger Beziehung zur Bildung von Huminstoffen, die bei der Rotte des Strohes auftraten.
    Notes: Summary The use of ultra-thin foils prepared from maple wood for measuring the wood-destroying capacity of soil fungi is described. Data are given on the reduction of dry-weight and tensile strength by the action of 27 highly active species from a total number of 280 microfungi. The decrease in lignin and cellulose content of wheat straw was studied with a selected number of fungi. The percentage reduction after an incubation period of 120 days was found to be between 31 and 52% for lignin, 33 and 66% for cellulose content respectively. A remarkable production of phenols was found in liquid cultures of Mammaria echinobotryoides, Hormiactis candida and Chaetomium piluliferum. The phenol production was more or less typical for all the examined fungi. There was a close relationship between the phenol metabolism and dark humic acid-like substances occurring during the decomposition of straw.
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  • 67
    ISSN: 1432-072X
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Der Einfluß der Nährmedien, der Inkubationstemperatur und des Kulturalters auf die Strahlenempfindlichkeit verschiedener Stämme von Penicillium viridicatum und Aspergillus flavus wird beschrieben. Die Reaktivierbarkeit bestrahlter Conidien war auf optimalen Nährmedien erhöht. Bei A. flavus wurde die Reaktivierbarkeit bestrahlter Conidien durch optimale Bebrütungstemperatur begünstigt, während die bestrahlten P. viridicatum-Stämme höchste relative Wachstumsraten bei suboptimalen Temperaturen zeigten. Die Strahlenempfindlichkeit der Conidien nahm mit deren Alter zu. Bei aktiv wachsenden Pilzkulturen war die Strahlenempfindlichkeit gegenüber älteren Kulturen erhöht.
    Notes: Summary The influence of the growth media, the incubation temperature, and the age of the cultures on the radiation sensitivity of different strains of Penicillium viridicatum and Aspergillus flavus is described. The recovery of irradiated conidia was higher on optimal media. The recovery of irradiated conidia of A. flavus was favored by optimal incubation temperature, while those of P. viridicatum showed highest relative growth rates at suboptimal temperatures. The radiosensitivity of the conidia increased with age. Actively growing cultures of the moulds were more sensitive to radiation than older ones.
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  • 68
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    Archives of microbiology 64 (1969), S. 369-376 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary P. nigrifaciens produces a water-insoluble blue pigment on solid media which forms cuboidal crystals among the cells. The pigment was prepared by bulk harvest of isolated colonies incubated 5 days at 15°C. The cells were extracted with DMF and the extract benzene-precipitated and chromatographed over Sephadex LH-20. Analytical data were compiled leading to a provisional structure closely related to the pigments of P. indigofera and P. lemonnieri.
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  • 69
    ISSN: 1432-072X
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Es wird das Vorkommen von Polysomensäulen bei Rhodopseudomonas palustris beschrieben. An Hand der Daten ergab sich, daß diese Polysomen aus zwei helixförmig angeordneten Ribosomensträngen aufgebaut sind, die eine linksdrehende Schraube bilden. Der Querschnitt der Schraube zeigt hexagonale Anordnung der Ribosomen. Der Steigungswinkel der Helices beträgt 200, der Gesamtdurchmesser der hexagonalen Polysomensäule beträgt 375 Å. Diese Polysomenart kommt lediglich in der begeißelten Polregion vor und ist dicht unter der Cytoplasmamembran lokalisiert. Die Polysomen stehen mit der Cytoplasmamembran in Kontakt. Ihre Längsachse läuft parallel zur Plasmamembran.
    Notes: Summary Helical arranged ribosomes were detected in the polar region of Rhodopseudomonas palustris cells. They are attached to the cytoplasmic membrane. The columnar polysomes are shaped of two helical strings of ribosomes, which are arranged around the axis of the screw. The vertical projection of the single ribosomes in one turn of the screw is a hexagon. The helices are left handed. The angle between the horizontal line and the ribosome chain in the helix is α=200. The diameter of the polyribosome column amounts to 375 Å.
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  • 70
    ISSN: 1432-072X
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    Topics: Biology
    Notes: Summary The carbohydrate composition and the specific activity of the trehalase of cyclic partially synchronised yeast populations have been investigated. Under glucose limitation and appropriate cultural conditions synchronous growth in a chemostat was achieved. The cells accumulated the reserve carbohydrates during the single cell phase between two buddings. The rapid degradation of part of these reserves began shortly before the swelling of the bud. The importance of the mobilisation of endogenous reserves for the development of the cell is discussed. The specific activity of the trehalase changed during the budding cycle. The result gives rise to the assumption that the synthesis of this enzyme is linked to the growth cycle.
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  • 71
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    Archives of microbiology 64 (1969), S. 387-395 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Measurements of nuclear positions in apical cells of homokaryotic mycelia and dikaryotic mycelium of Schizophyllum commune showed that nuclei occupied a near central position in most cases. Forward nuclear movements observed in living hyphal apices occurred at rates within the range of hyphal growth and could account for the maintenance of centrally located nuclei. Opposed nuclear movements followed mitosis and greatly exceeded the rate of hyphal growth. Septum disruption and rapid nuclear movements characterized an A xBmut homokaryon. Neither cytoplasmic streaming nor actively participating granules or filaments could account for any of these nuclear movements.
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  • 72
    ISSN: 1432-072X
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    Topics: Biology
    Notes: Summary Ultrastructural study of Chlamydobotrys stellata shows that whilst the basic structure is volvocalean there are certain abnormalities for a green cell. The thylakoids are predominantly separated from each other in all but the central region of the cell, where small grana are present, under the growth conditions used in these experiments. Approximately three quarters of the thylakoids are separated from each other. Reticulate areas of disorganization are also present in the central region of the chloroplast. The absence of a demonstrable Hill reaction in C. stellata may be the result of restricted grana formation.
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  • 73
    ISSN: 1432-072X
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung 1. Alle hydrogenase-positiven Chlorobium-Stämme (12 von insgesamt 17 untersuchten Stämmen) können Cystein bis zu einem gewissen Grade als S-Quelle für das Wachstum mit H2 verwerten. Eine assimilatorische Sulfatreduktion its nicht vorhanden; Methionin, Cystin, Cysteinsäure, Thioglycolat, Thioacetamid und Sulfit können in den geprüften Konzentrationen nicht als S-Quellen genutzt werden. 2. 35S-Cystein wird während des Wachstums mit H2 von den Zellen aufgenommen und 35S-markiertes Methionin gefunden. Beide Aminosäuren wurden im Zellprotein nachgewiesen. Das begrenzte Wachstum mit H2 wird darauf zurückgeführt, daß nicht alle S-Verbindungen der Zellen aus Cystein gebildet werden können. Die Unfähigkeit der Organismen, das normalerweise als S-Quelle genutzte Sulfid aus Cystein abzuspalten, wurde durch Versuche zur CO2-Fixierung mit Cystein nachgewiesen. 3. Bei gleichzeitiger Anwesenheit von Sulfid oder Thiosulfat und H2 werden beide H-Donatoren nebeneinander zur CO2-Fixierung genutzt. In statischer Kultur werden ca. 50% des fixieten CO2 durch H2 als H-Donator reduziert; in kontinuierlicher Kultur konnte der Anteil des mit H2 fixierten CO2 auf etwa 90% der Gesamtfixierung gesteigert werden. 4. Im Bereich niedriger Lichtintensitäten sind die CO2-Fixierungsraten mit H2 oder Thiosulfat gleich. Bei der CO2-Fixierung mit H2 tritt Lichtsättigung etwa bei 100–150 Lux ein, während die CO2-Fixierung mit Thiosulfat erst bei 700 Lux Lichtsättigung erreicht. Dieses Verhalten führt bei höheren Lichtintensitäten zu einer geringeren CO2-Fixierungsrate mit H2 im Vergleich zur Fixierungsrate mit Thiosulfat.
    Notes: Summary 1. All hydrogenase-positive Chlorobium-strains (12 out of 17 strains tested) can grow to some extent with cysteine as a sulfur source, when molecular hydrogen is electron donor. An assimilatory sulfate reduction does not exist. Methionine, cystine, cysteic acid, thioglycolate, thioacetamide, and sulfite in the concentrations tested can not be utilized as a source of cell sulfur. 2. 35S-cysteine is taken up by the cells during growth with hydrogen, and the 35S-label is found in methionine; both these labeled amino acids were shown to occur in the cell protein. The limited growth observed with hydrogen and cysteine may be due to the possibility that not all sulfur compounds of the Chlorobium cells can be built up from cysteine. Free sulfide, normally used as sulfur source, is not formed from cysteine as was shown by CO2-fixation experiments with cysteine. 3. If sulfide or thiosulfate is present in addition to hydrogen, both hydrogen donors are used simultaneously for CO2-fixation. In batch culture about 50% of the CO2 assimilated is reduced with hydrogen; in continous culture the portion of CO2 reduced by hydrogen could be increased to about 90% of total fixation. 4. At low light intensity the rates of CO2-fixation in the presence of hydrogen or thiosulfate are equal. Light saturation of CO2-fixation with hydrogen is reached at about 100–150 lux whereas CO2-fixation with thiosulfate becomes saturated at about 700 lux. At high light intensities this feature leads to a lower CO2-fixation rate with hydrogen.
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  • 74
    ISSN: 1432-072X
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    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Arbeit beschreibt Aufbau und Eigenschaften einer Elektrode zur kontinuierlichen Messung des Sauerstoffpartialdruckes in Fermenterkulturen. Die nach dem polarographischen Prinzip arbeitende Elektrode leitet sich von der Clarkschen Meßanordnung ab. Ihr wesentliches Merkmal ist die Auftrennung in zwei selbständige Bauelemente, einen Membran-tragenden Glasmantel und den Elektroden-tragenden Meßgeber. Der Elektrodenmantel wird gemeinsam mit dem Fermentergefäß autoklaviert, der thermolabile Meßfühler dagegen erst nachträglich eingesetzt. Die Eichung der Elektrode kann vor dem Autoklavieren in einem Spezialgefäß oder danach im Fermentergefäß vorgenommen werden. Der sterilisierbare, in die Kulturlösung hineinragende Elektrodenmantel wird von der Lösung durch eine O2-permeable, 250μ starke Siliconglasgewebemembran abgeschlossen. Zwischen Siliconschicht und der blanken Platinoberfläche der Kathode befindet sich eine weitere, stabilisierende Membran von 12 μ Stärke (Cellophanfolie). Die Empfindlichkeit der Elektrode beträgt 10−9 A/mm Hg pO2 bei 37°C, die Einstellzeit auf 95% des Endwertes 50 sec bei 37°C. Die Abhängigkeit der Messungen von der Turbulenz des Mediums ist zwischen 400 und 1200 UpM Rührergeschwindigkeit zu vernachlässigen. Wiederholtes Autoklavieren der Siliconmembran hat keinen Einfluß auf die Einstellzeiten.