ALBERT

Description: In der Baugrube „Neubau Geologisches Landesamt Rheinland-Pfalz“ in Mainz-Hechtsheim waren tertiäre und quartäre Sedimente in gut zugänglichen Profilen aufgeschlossen. Über Kalksteinen und Mergel der Oberen Hydrobienschichten (Miozän) folgen arvernensis-Schotter und „Ältere Weisenauer Sande” (Pliozän). „Jüngere Weisenauer Sande“ (Altestpleistozän) sind schwermineralogisch in situ und in Umlagerungssedimenten nachweisbar. Zur Hauptterrassenzeit (Altpleistozän) hat sich der Rhein in die Weisenauer Sande eingeschnitten und die dabei entstandenen Rinnen mit Kies und Sand verfüllt. Periglaziale Schuttdecken und Jungwürm-Löß bilden den Abschluß der känozoischen Schichtenfolge.

Description: Abstract: Tertiary and quaternary sediments were visible in the excavation for the new office building of the Geological Survey of Rheinland-Pfalz in Mainz-Hechtsheim. Arvernensis- gravel and Early Weisenau sands (pliocene) follow limestones and marls of the Upper Hydrobien beds (miocene). With the help of heavy mineral analysis late Weisenau sands (oldest pleistocene) were detected in situ and in moved sediments. The river Rhine accumulated the main terrasse in the old pleistocene, forming channels which later filled with sand and gravel. Periglacial detritus and loess of the younger würm-glacial complete the cenozoic sequence.

Description: research

Description: Anwachslinien von 20 Bivalvenschalen unterschiedlicher Oligozän- Fundstellen im Mainzer Becken und von 14 rezenten Bivalvenschalen wurden untersucht. Die rupelischen Formen dokumentieren 14tägige Anwachslinienrhythmen, die chattischen Mollusken zeigen eher jahreszeitlich bedingte Zyklen.

Description: Abstract: Valves of 20 Oligocene pelecypods from the Mainz Basin and 14 recent valves were examined for growth patterns. Whereas the microgrowth increments of the Rupelian samples indicate fortnightly tidal intervals, the Chattian specimens show annual (seasonal) variations in growth.

Description: research

Description: Aus den Jeckenbach-Schichten von Niedermoschel/Pfalz wird der seltene Fund einer Hai-Eikapsel beschrieben. Er wird der Gattung Fayolia RENAULT & ZEILLER zugeordnet und mit allen bisherigen Fayolia-Arten verglichen. Paläoökologische Anmerkungen zum Fundhorizont und zum möglichen Erzeuger der Hai-Eikapsel werden gemacht.

Description: Abstract: Egg capsules from sharks are very seldomly found in the permocarboniferous Saar-Nahe basin. Three finds have been done up to now, but only one find comes from the lower Rotliegend. A second one comes now from the black shale called Niedermoschel bed (Jeckenbach formation, northern Palatinate). It belongs to the genus Fayolia RENAULT & ZEILLER. It will be described and compared with all other species of Fayolia. In addition flora and fauna of the Niedermoschel bed are listed, and their paleoecological relationships are discussed. The origination of the egg capsule is interpreted.

Description: research

Description: Die lithostratigraphische Einheit Lauterecken- bis Odernheim-Schichten L-O5 nach Boy & Fichter (1982) wird anhand von sechs Profilen detailliert mit allen Horizonten beschrieben. Sechs neue Leithorizonte werden aufgestellt. Auf die Fossilführung wird eingegangen. Die laterale fazielle Entwicklung wird dargestellt und ein Bild der Paläolandschaft entwickelt.

Description: Abstract: Boy & Fichter (1982) presented a new concept concerning the subdivision of the monotonous sediment series of the former Upper Kusel to Middle Lebach Group (sensu Farke 1974) of the Rotliegend of the Saar-Nahe basin. They summarised the lithostratigraphical sections of the Lauterecken-, Jeckenbach- and Odernheim formations and sub-divided this new section by means of 10 informal units (L-O1 to L-O10). The lithostratigraphical unit L-OS5 is detailled here in six profiles with descriptions of all horizons given. Six new index horizons are erected. A guide to the fossils is introduced. The development of the lateral facies is described and a picture of the palaeolandscape is presented.

Description: research

Description: Umfangreiches neues Material erlaubte die Untersuchung einer Brachiopodenart, die Rösler 1954 unter dem Namen Leptostrophia dahmeri veröffentlichte. Für diese Art konnte ein Lectotypus festgelegt sowie eine revidierte Diagnose erstellt werden. Die Untersuchungen zeigten, daß diese Art in keine der bisher veröffentlichten Gattungen gestellt werden kann, daher wird eine neue monotypische Gattung (Pseudoleptostrophiagen. nov.) mit der Typusart Leptostrophia dahmeri aufgestellt. Die Problematik der Zuordnung der neuen Gattung zu den Familien Leptostrophiidae und Amphistrophiidae (im Sinne von Rong & Cocks 1994) wird diskutiert.

Description: Abstract: In 1954 RÖSLER erected the brachiopod species Leptostrophia dahmeri (Strophomenoidea, Rheinisches Schiefergebirge, Lower Devonian). New, numerous material allowed the reexamination of this species. A lectotyp is selected and a revised diagnosis is given. A new genus Pseudoleptostrophia is erected with the type species Leptostrophia dahmeri.The problems concerning the allocation of the new genus to the brachiopod families Leptostrophiidae and Amphistrophiidae as defined by RONG & COCKS (1994)are discussed.

Description: research

Description: Die Geologie des Arbeitsgebietes Derudeb ist mit Methoden der Fernerkundung und Geo- Informationssystemen auf der Grundlage einer begrenzten Datenbasis untersucht worden. Als Ergebnis wurde ein geologisches Kartenblatt im Maßstab 1 : 250 000 erstellt. Das Gebiet der südlichen Red Sea Hills, im NE des Sudan gelegen, bildet den nubischen Teil des Arabisch-Nubischen Schildes.

Description: thesis

Description: DFG, SUB Göttingen

Description: Im nördlichen Bereich der Provinz Kantabrien (Nordspanien) wurden Sedimente der "Mittelkreide" (Oberalb und Cenoman) unter stratigraphischen, faziellen und sedimentologi sehen Gesichtspunkten bearbeitet. Strukturell gehört die Region zum Nordkantabrischen Becken (NCB), dessen Einsenkung mit tektonischen Bewegungen im mittleren Valangin beginnt. Das NCB ist eines der zahlreichen Sedimentbecken, die sich infolge des mesozoischen Riftings und Spreadings in der Biscaya auf dem iberischen Nordschelf bilden. Strukturgeologisch zeigt das NCB eine E/W-Ausrichtung zwischen zwei Hochgebieten im S und N (Cabuemiga-Rücken und Liencres-Hoch), die als "Santillana-Achse" bezeichnet wird. Im W grenzt das NCB an das Paläozoikum des Asturischen Massivs. Östlich Santander wird es strukturell und faziell durch die N/S-streichende Rio-Miera-Flexur vom hochsubs identen Basko-Kantabrischen Becken abgetrennt. Die Sedimentation im NCB wird stark von tektonischen Ereignissen im sich bildenden Biscaya-Ozeans beeinflußt, durch welche die Strukturierung der Schichtenfolge in sedimentäre Megasequenzen erfolgt. Im Alb und Cenoman können folgende Megasequenz-Grenzen erkannt werden, durch welche die Megasequenzen des Alb und Cenoman definiert werden: • Santander-Tectoevent (Cenoman/Turon-Grenzbereich) • Vraconian Tectoevent (hohes Oberalb) • "Mittelalb-Ereignis" ("break-up unconformity", [?hohes] Unteralb). Das Mittelalb-Ereignis fuhrt im Arbeitsgebiet zum Zerbrechen der faziell wenig differenzierten Urgon-Karbonatplattformen des Clansay (Oberapt/Unteralb) in ostvergente Kippschollen. In den entstehenden N/S-orientierten Halbgräben werden im Mittelaib fluvio-deltaische Klastika abgelagert, während auf den Hochschollen eine Verkarstung erfolgt. Im tiefen Oberalb initiiert ein transgressiver Puls die weit verbreitete Ablagerung mariner Sedimente im NCB. Dieses transgressive Ereignis ist in ganz Iberien nachzuweisen. Im Laufe des Oberalb kommt es zu einem Onlap mariner Sedimente auch auf den ehemals emergenten Hochschollen und zu einem Ausgleich des durch das Mittelalb-Ereignis erzeugten Paläoreliefs. Durch weit verbreitete Emersion des NCB's infolge tektonischer Bewegungen im oberen Oberalb (Vraconian Tectoevent) wird die sedimentäre Megasequenz des Alb beendet. Die sedimentäre Megasequenz des Cenoman beginnt im Alb/Cenoman-Grenzbereich mit der Progradation deltaischer Klastika. Die im NCB der Santillana-Achse folgend von W nach E kanalisiert werden. Dieses "Santillana-Delta" mündet im Bereich Galizano/Langre östlich Santander in das Basko-Kantabrische Becken und verzahnt sich dort mit den Prodelta-Sedimenten des Valmaseda-Deltas ("Schwarzer Flysch" der Bilbao-Region). Die differentielle Subsidenz im NCB in Folge des Vraconian Tectoevents wird von den Delta-Sedimenten ausgeglichen. Im tiefen Untercenoman (untere Mantelliceras mantelli-Zone) gestaltet eine bedeutende transgressive Faziesentwicklung das gesamte NCB in einen vollmarinen, karbonatisch dominierten Ablagerungsraum um. Dieser transgressive Puls dürfte mit der "Untercenoman-Transgression" sensu lato korrelieren. Im Cenoman können folgende Ammoniten-Biozonen erkannt werden: • Obercenoman: Eucalycoceras pentagonum-Zone, und Metoicoceras geslinianum-Zone [pars] • Mittel cenoman: [Cunningtoniceras inerme-Zone], Acanthoceras rhotomagense-Zone und A. jukesbrownei-Zone • Untercenoman: Mantelliceras mantelli-Zone und M. dixoni-Zone. Das höchste Obercenoman (oberer Teil der geslinianum-Zone und die Neocardioceras juddii-Zone) fehlt im NCB. In der oberen mantelli-Zonc des NCB etabliert sich in weiten Bereichen die flachmarine Karbonat-Fazies der Altamira-Plattform, die sich östlich der Rio-Miera-Flexur mit mächtigen Beckensedimenten (Mergel, Knollenkalke, Kalk/Mergel-Rhythmite) verzahnt. Im Mittel- bis unteren Obercenoman wird die Altamira-Plattform in drei Schritten von E nach W "ertränkt". Die prominenten Drowning-Unconformities (mineralisierte Hartgründe mit Ammoniten) werden dabei stufenweise nach W jünger. Im Obercenoman (pentagonum-Zono) ist die gesamte Altamira-Plattform ertränkt und weite Teile des NCB werden in die Beckensedimentation einbezogen. Die Ablagerungsgeschichte des Cenoman wird durch das Santander-Tectoevent in der oberen geslinianum-Zonc beendet, infolgedessen weite Teile des NCB trockenfallen. Selbst in hochsubsidenten Beckenprofilen ist der Cenoman/Turon-Grenzbereich durch eine Schicht lücke gekennzeichnet. Die fazielle Entwicklung der cenomanen Megasequenz ist durch die schubweise voranschreitende ("pulsierende") Cenoman-Transgression geprägt. Insgesamt können im Cenoman sechs Sequenzgrenzen (SB's) erkannt werden, durch die die Ablagerungssequenzen DS Ce I bis VI definiert werden. Ihre stratigraphischen Positionen sind: • SB Ce VI = obere geslinianum-Zonc • SB Ce V = Wende Mittel/Obercenoman • SB Ce IV = basale jukesbrownei-Zone • SB Ce III = hohe dixoni-Zone • SB Ce II = obere mantelli-Zone • SB Ce I = untere mantelli-Zone. Im regionalen Vergleich zeigt sich für das Cenoman eine gute Übereinstimmung mit sequentiellen Gliederungen aus dem Basko-Kantabrischen Raum. Überregionale Vergleiche dokumentieren, daß viele der Meeresspiegel-Bewegungen im Cenoman (z.B. SB Ce III, mfz in der rhotomagense-Zone, SB Ce IV, HST in der pentagonum-Zone) über weite Entfernungen korreliert werden können und wahrscheinlich eustatische Signale darstellen. Die Korrelation mit der "globalen Meeresspiegel-Kurve" (Exxon Chart) ist schlecht. Betrachtet man die im Cenoman im NCB abgelagerten Sedimente als "2nd-order cycle", so zeigt sich ein übergeordneter transgressiver Trend mit einem maximalen Onlap im Obercenoman innerhalb der mfz von DS Ce VI (pentagonum-Zone). Das NCB zeigt im Oberalb und Cenoman im biogeographischen Vergleich starke tethyale Einflüsse. Das Turrilites scheuchzerianus/Neohibolites ultimus-Evert. im tiefen Mittelcenoman des NCB korreliert in bio-, sequenz- und Isotopen-stratigraphischer Hinsicht mit dem Actinocamax primus-Event NW-Europas, womit eine eventstratigraphische Anbindung an das "temperierte" Cenoman erreicht werden kann.

Description: Mid-Cretaceous (Upper Albian and Cenomanian) sediments in the northern part of the province of Cantabria (northern Spain) were investigated with the emphasis on stratigraphical and sedimentological aspects. Structurally, the area belongs to the North Cantabrian Basin (NCB), the depositional history of which started with distensional tectonic movements in the Mid-Valanginian. The NCB is one of the numerous sedimentary basins which developed on the north Iberian continental margin in consequence of the rifting and spreading in the Bay of Biscay during Mesozoic times. It is a gulf-like basin with an E/W-elongation ("Santillana axis"). In the south and in the north the NCB is bordered by the Cabuemiga Ridge and the Liencres High, respectively. To the west, the NCB is bordered by the Palaeozoic Asturian Massif; in the east, the N/S-trending Rio Miera Flexure forms a structural boundary to the strongly subsiding Basco-Cantabrian Basin. The depositional history of the NCB was strongly influenced by tectonic events which can be related to the evolving Biscay Ocean. These tectoevents give rise to a gross subdivison of the succession into sedimentary megasequences. Three tectonically induced megasequence boundaries can be recognized in the Albian and Cenomanian, defining the Albian and Cenomanian megasequences: • Santander-Tectoevent (Cenomanian/Turonian boundary interval) • Vraconian Tectoevent (late Late Albian) • "Middle Albian event" (break-up unconformity, [?late] Early Albian). The "Middle Albian event" caused a disintegration of the widespread Urgonian Clansay platforms (Late Aptian/Early Albian) into a palaeo-relief of eastward-dipping tilted blocks. In the N/S trending halfgrabens, fluvio-deltaic clastics were deposited during the Middle Albian, whereas the exposed tilted block crests were karstified. A strong transgressive pulse flooded the NCB in the early part of the Late Albian, giving rise to the widespread deposition of marine Upper Albian sediments. This transgressive event can also be recognised in southern Iberia and Portugal. During the later part of the Late Albian, the emergent crestal areas of the tilted blocks were onlapped by marine sediments, resulting in the filling-up of the Middle Albian palaeo-relief. Tectonic movements in the latest Albian (Vraconian tectoevent), causing emergence in wide parts of the NCB, terminated the Albian Megasequence. The Cenomanian megasequence started in the Albian/Cenomanian boundary interval with progradation of deltaic clastics, which were channelized (following the Santi liana-axis) into an eastward direction. This "Santillana Delta" flowed into the Basco-Cantabrian Basin east of Santander, where an interfingering with the prodeltaic sediments of the Valmaseda Delta ("Black Flysch" of the Bilbao area) took place. The differential subsidence in the NCB due to the Vraconian tectoevent was compensated by the deltaic sedimentation. In the lower part of the Mantelliceras mantelli Zone, a transgressive pulse flooded the NCB and led to the deposition of marine, predominantly calcareous sediments. This transgressive event is thought to correlate with the "Early Cenomanian transgression" sensu lato. In the Cenomanian succession of the NCB, the following ammonite zones can be recognized: • Late Cenomanian: Eucalycoceras pentagonum Zone and Metoicoceras geslinianum Zone [pars] • Middle Cenomanian: [Cunningtoniceras inerme Zone], Acanthoceras rhotomagense Zone and A. jukesbrownei Zone • Early Cenomanian: Mantelliceras mantelli Zone and M. dixoni-Zone. The upper part of the Upper Cenomanian (upper part of the geslinianum Zone and the Neocardioceras juddii Zone) is missing in the NCB. In the upper part of the mantelli Zone, deposition of the shallow marine carbonate sediments of the Altamira Platform became established over large areas of the NCB. In the strongly subsiding area east of the Rio Miera Flexure, thick successions of basinal sediments (marls, nodular limestones, marl/limestone rhythmites) were deposited contemporaneously. During the Middle to early Late Cenomanian, the Altamira Platform was drowned in three successive steps from east to west. The developing drowning unconformities (condensed, mineralized hardgrounds with ammonites) young towards the west, resulting in a backstepping of the Altamira Platform. In the Late Cenomanian (pentagonum Zone), all former sites of shallow marine carbonate deposition were drowned. The depositional history of the Cenomanian was terminated in the higher part of the geslinianum Zone when tectonic movements of the Santander tectoevent caused widespread emersion of the NCB. The resulting Cenomanian/Turonian boundary hiatus can be recognized both in the condensation horizons on top of the submerged platform as well as in the basinal successions. The facies development of the Cenomanian Megasequence is dominated by the pulsatory nature of the "Cenomanian transgression". Within the Cenomanian succession of northern Cantabria, six sequence boundaries can be recognized, which define six depositional (3rd-order) sequences (DS Ce I - VI). The stratigraphic positions of the sequence boundaries (SB) are as follows: • SB Ce VI = upper geslinianum Zone • SB Ce V = Middle/Late Cenomanian boundary interval • SB Ce IV = basal jukesbrownei Zone • SB Ce III = upper dixoni Zone • SB Ce II = upper mantelli Zone • SB Ce I = lower mantelli Zone. Comparison of this sequential subdivision with regional cycle charts from the Basco-Cantabrian area reveals good agreement, whereas correlation with the "global sea-level curve" (Exxon Chart) is poor. The extent to which many of the sea-level events in the Cenomanian (e.g. SB Ce III, mfz within the rhotomagense Zone, SB Ce IV, HST in the pentagonum Zone) can be correlated between basins elsewhere in Europe and Tunisia suggests that they were probably of eustatic nature. Considering the Cenomanian Megasequence as a "2nd-order cycle", an overall transgressive trend occurs throughout the Cenomanian; maximum coastal onlap was reached during the maximum flooding of DS Ce VI (pentagonum Zone). Palaeobiogeographically, the NCB shows strong tethyan affinities in the Late Albian and Cenomanian. The Turrilites scheuchzerianus/Neohibolites ultimus event in the early Middle Cenomanian permits a correlation with the Actinocamax primus event of the temperate Cenomanian of northern Europe by means of bio-, sequence and isotope stratigraphy.

Description: Los sedimentos del Cretácico medio (Albiense superior/Cenomaniense) en la parte septentrional de la Provincia de Cantabria han sido estudiados, centrándose en aspectos estratigráficos y sedimentolögicos. El área de estudio pertenece estructural mente a la Cuenca Norcantábrica (NCB), cuya historia depositional comenzó con movimientos tectónicos distensivos en el Valanginiense medio. La NCB es una de las numerosas cuencas sedimentarias que se desarrollaron en el margen continental norteibérico como consecuencia del "rifting" y apertura del golfo de Vizcaya durante el Mesozoico. Es una cuenca con forma de golfo con una elongatión E/W ("Eje de Santillana"). Los límites septentrional y meridional de la NCB son el "Liencres High" y el Escudo de Cabuemiga respectivamente. Hacia el Oeste, la NCB queda confinada por el Macizo Paleozoico Asturiano; en el Este, el límite estructural conocido como Flexión del Río Miera de dirección N/S, la separa de la Cuenca Vasco-cantábrica mucho más subsidente. La historia deposicional de la NCB estuvo fuertemente influenciada por eventos tectónicos que pueden ser relacionados con la evolution del oceano de Vizcaya. Estos tectoeventos dieron lugar a una gruesa subdivision de la sucesión en megasecuencias sedimentarias. Tres límites de megasecuencias, que están inducidos por la tectónica, pueden ser reconocidos en el Albiense y Cenomaniense, definiendo respectivamente las megasecuencias albienses y cenomanienses: • Tectoevento de Santander (intervalo límite del Cenomaniense/Turoniense) • Tectoevento Vraconiense (Albiense superior tardío) • "Evento del Albiense medio" (discordancia de ruptura, Albiense inferior [?tardio]). El "Evento del Albiense medio" causo una desintegración de las plataformas urgonianas clansayenses (Aptiense superior/Albiense inferior), que estaban muy extendidas en paleorelieves de bloques basculados hacia el Este. Se produjo durante el Albiense medio una sedimentatión clástica fluvio-deltaica en los semi-grabenes, de dirección N/S, mientras que las cimas expuestas de los bloques basculados sufrieron procesos de karstificatión. Un fuerte pulso transgresivo inundó la NCB al comienzo del Albiense superior, dando lugar al depósito de sedimentos marinos en el Albiense superior due alcanzaron una muy amplia extensión. Durante la parte superior del Albiense superior las crestas de los bloques basculados fueron recubiertas por sedimentos marinos, indicando el equilibrio del paleorelieve en el Albiense medio. Los procesos tectónicos al final del Albiense superior (Tectoevento Vraconiense), que causaron la emersión de amplias zonas de la NCB, terminan la megasecuencia albiense. La megasecuencia cenomaniense comenzó en el limite Albiense/Cenomaniense con la progradatión de material clástico deltaico que fue canalizado (siguiendo el Eje de Santillana) hacia el Este. Dicho delta ("Delta de Santillana") discurria al Este de Santander hacia la Cuenca Vasco-cantabrica, interfiriendo con los sedimentos de prodelta del Delta de Valmaseda ("Flysch Negro"). En la parte inferior de la zona de Mantelliceras mantelli, un pulso transgresivo inundó la NCB y permitió el depósito de sedimentos marinos, predominantemente calcáreos. Este evento transgresivo puede ser correlacionado con la "transgresión del Cenomaniense initial" sensu lato. En la sucesion Cenomaniense de la NCB pueden ser reconocidas las siguientes zonas: • Cenomaniense superior: Zona de Eucalycoceras pentagonum y la Zona de Metoicoceras geslinianum [pars] • Cenomaniense medio: [Zona de Cunningtoniceras inerme], Zona de Acanthoceras rhotomagense y Zona de A. jukesbrownei • Cenomaniense inferior: Zona de Mantelliceras mantelli y Zona de M. dixoni. La parte superior del Cenomaniense superior (parte superior de la zona de M. geslinianum y la Zona de Neocardioceras judii) está ausente en la NCB. Los sedimentos marino-someros de naturaleza carbonatada de la "Plataforma de Altamira" comenzaron a depositarse en amplias zonas de la NCB en la parte superior de la zona de mantelli. Al Este de la Flexión de Río Miera, en un área fuertemente subsidente, fueron depositadas contemporáneamente potentes sucesiones de sedimentos de cuenca (margas, calizas nodulares y ritmitas de marga/caliza). Durante el Cenomaniense medio hasta la base del Cenomaniense superior, la Plataforma de Altamira fue inundada desde el Este al Oeste en tres intervalos sucesivos. El desarrollo de discordancias de inundatión ("drowning unconformities" = series condensadas, "hardgrounds" mineralizados con ammonites) resultan más recientes hacia el Oeste, concluyendo en un basculamiento hacia atrás de la Plataforma de Altamira. En el Cenomaniense superior (Zona de pentagonum) todos los anteriores lugares caracterizados por el depósito de carbonates marino-someros fueron anegados. La historia deposicional del Cenomaniense acabó en la parte alta de la zona de geslinianum, cuando movimientos tectonicos del Tectoevento de Santander causaron la emersión generalizada de la NCB. El hiato resultante puede ser reconocido en los horizontes condensados a techo de las plataformas sumergidas e igualmente en las sucesiones de cuenca. El desarrollo de facies del Cenomaniense está dominado por el carácter de pulsos que tuvo la "transgresión cenomaniense". Seis límites de secuencia pueden reconocerse dentro de la sucesión cenomaniense del norte de Cantabria, los cuales definen seis secuencias deposicional es de tercer orden (DS Ce I-VI). La positión estratigráfica de los límites de secuencia (SB) son los siguientes: • SB Ce VI = parte superior de la Zona de geslinianum • SB Ce V = intervalo límite del Cenomaniense medio/superior • SB Ce IV = base de la Zona de jukesbrawnei • SB Ce III = parte superior de la Zona de dixoni • SB Ce II = parte superior de la Zona de mantelli • SB Ce I = parte inferior de la Zona de mantelli. Una comparación de esta subdivisión secuencial con las tablas de ciclos regionales del reino vasco-cantábrico revela una buena correlatión, mientras que la correlatión con la "tabla global" ("Exxon chart") es pobre. La correlatión entre varias cuencas sugiere una causa eustática para los numerosos eventos de cambios del nivel del mar en el Cenomaniense (por ejemplo SB Ce III, mfz dentro de la Zona de rhotomagense, SB Ce IV, HST en la Zona de pentagonum). Considerando la megasecuencia del Cenomaniense como un "ciclo de segundo orden", una tendencia transgresiva general ocurrió a lo largo del Cenomaniense, el máxirno "onlap" costero fue alcanzado durante la máxima inundatión de la DS Ce VI (Zona de pentagonum). Desde el punto de vista paleobiogeográfico, la NCB muestra fuertes afinidades tethyales en el Albiense superior y el Cenomaniense. El "Evento de Turrilites scheuchzerianus/Neohibolites ultimus" al comienzo del Cenomaniense medio permite una correlation con el "Evento de Actinocamax primus" del Cenomaniense de la Provincia templada norteuropea.

Description: thesis

Description: DFG, SUB Göttingen

Description: Die Stammesgeschichte der Ordnung Ptenoglossa (Gastropoda, Caenogastropoda) wird anhand von 179 rezenten und fossilen Arten bis ins Paläozoikum zurückverfolgt. Ihre rezenten Überfamilien, die Cerithiopsoidea, Triphoroidea und Janthinoidea ernähren sich karnivor. Eine kollabral berippte Larvalschale stellt in den rezenten Überfamilien den ursprünglichen Zustand dar und ist die aussagekräftigste schalenmorphologische Symplesiomorphie. Dies erweist sich durch Radulauntersuchungen und den Fossilbericht. Cerithiopsoidea und Triphoroidea fressen Schwämme und bilden gemeinsam mit den mesozoischen Protorculidae ein Monophylum. Die Janthinoidea fressen Coelenteraten. Sie sind nahe mit den mesozoischen Zygopleuridae verwandt. Die Stammlinien der Schwamm- und Coelenteratenfresser waren schon in der Trias getrennt. Die Zygopleuroidea (Zygopleuridae, Pseudozygopleuridae und Protorculidae) sind folglich ein Parataxon. In allen drei Familien der Zygopleuroidea kommt die kollabral berippte Larvalschale vor und repräsentiert den ursprünglichen Zustand. Die paläozoischen Pseudozygopleuridae stellen wahrscheinlich die Schwestergruppe der rezenten und mesozoischen Ptenoglossa dar. Arten der Pseudozygopleuridae mit planktotropher und nicht planktotropher Frühontogenese können biometrisch getrennt werden. Die Abgrenzung nicht planktotropher Pseudozygopleuridae von den devonischen bis karbonischen Palaeozygopleuridae ist schwierig, weil letztere anhand eines nicht planktotrophen Protoconchs definiert wurden. Mit Hilfe von Protoconchvermessungen ist es jedoch meist möglich, beide Gruppen zu trennen. Die Außengruppe der Ptenoglossa sind die Cerithimorpha, die im Paläozoikum durch die Acanthonematidae und die Murchisoniidae repräsentiert werden. Die paläozoischen Acanthonematidae werden neu gefaßt und enthalten nun unter anderem die Gattungen Orthonema, Palaeostylus, Cerithioides und Knightella. Sie zeichnen sich durch einen heliciformen Protoconch aus, der sich grundsätzlich von dem der Pseudozygopleuridae (Ptenoglossa) unterscheidet. Mithin ist der Protoconch der Pseudozygopleuridae die wesentliche schalenmorphologische Apomorphie der Ptenoglossa. 30 Arten werden neu beschrieben (siehe Anhang A), davon 2 rezente, 8 aus dem Tertiär, 1 aus der Kreide, 13 aus der Trias, 1 aus dem Perm und 5 aus dem Karbon. Turritella hybrida MONSTER non DESHAYES erhält den neuen Namen Zygopleura hybridissima nom. nov. 5 neue Gattungen werden errichtet: Antiphora n. Gen. (Triphoroidea, Tertiär), Eorex n. gen. (Triphoroidea, Tertiär), Atorcula n. gen. (Protorculidae, Trias), Azyga n. gen. (Zygopleuridae, Trias) und Stiazyga n. gen. (Zygopleuridae, Trias). Ampezzopleurinae n. subfam. wird als Unterfamilie der Zygopleuridae WENZ errichtet. Nystiellinae CLENCH & TURNER erhält Familienstatus (Nystiellidae). Die Untergattung Cerithiopsis (Vatopsis) GRÜNDEL wird zur Gattung erhoben und von den Cerithiopsidae zu den Eumetulidae transferiert. Tembrockia GRÜNDEL wird von den Cerithiopsidae zu den Eumetulidae transferiert. Variseila DOCKERY wird von den Triforidae JOUSSEAUME zu den Eumetulidae GOLIKOV & STAROBOGATOV transferiert. Ampezzopleura BANDEL wird von den Protorculidae BANDEL zu den Zygopleuridae WENZ transferiert. Zygopleura tenuis (MÜNSTER) sensu Zardini wird als neue nominelle Art Ampezzopleura tenuis BANDEL betrachtet, für die ein Lectotyp hinterlegt wird. Teutonica SCHRÖDER wird von den Cerithiopsidae zu den Zygopleuridae transferiert. Orthonema MEEK & WORTHEN wird von den Turritellidae LOVÉN zu den Acanthonematidae WENZ zurücktransferiert. Palaeostylus MANSUY wird von den Procerithiidae COSSMANN zu den Acanthonematidae transferiert. Knightella LONGSTAFF wird von den Pseudozygopleuridae KNIGHT zu den Acanthonematidae transferiert. Cerithioides HAUGHTON wird von den Murchisoniidae zu den Acanthonematidae WENZ transferiert. Die systematische Stellung einiger weiterer Taxa wird kritisch hinterfragt. Etliche Arten werden anderen Gattungen zugeordnet (siehe Anhang A "comb. nov.").

Description: The phylogeny of the order Ptenoglossa (Gastropoda, Caenogastropoda) is traced back into the Paleozoic by studying 179 Recent and fossil species. The Recent superfamilies Cerithiopsoidea, Triphoroidea und Janthinoidea are carnivorous. A larval shell with collabral ribs represents the plesiomorphic state in the Recent superfamilies and it is the most informative symplesiomorphy that concerns to the shell morphology. Evidence for that is given by the radula morphology and the fossil record. Cerithiopsoidea and Triphoroidea feed on sponges and form a clade with the Mesozoic family Protorculidae. The Janthinoidea feed on coelenterates. They are closely related to the Mesozoic family Zygopleuridae. The stem lines of sponge eaters and coelenterate eaters have been separated from each other at least since the Triassic. Thus, the superfamily Zygopleuroidea (Zygopleuridae, Pseudozygopleuridae and Protorculidae) is a parataxon. In all three families of the Zygopleuroidea a larval shell with collabral ribs occurs and represents the plesiomorphic state. The Paleozoic Pseudozygopleuridae are presumably the sister-group of the Recent and the Mesozoic Ptenoglossa. Species of the Pseudozygopleuridae with planktotrophic and non-planktotrophic larval development can be separated from each other by measuring their protoconchs. The separation of non-planktotrophic Pseudozygopleuridae from Devonian and Carboniferous species of the Palaeozygopleuridae is difficult because Palaeozygopleuridae were defined by a non-planktotrophic protoconch, whereas Pseudozygopleuridae were defined by a larval shell of the planktotrophic type. But in most cases it is possible to identify the species by protoconch measurements. The outgroup of the Ptenoglossa are the Cerithimorpha which are represented in the Paleozoic by the families Acanthonematidae and Murchisoniidae. The Paleozoic Acanthonematidae are newly defined and contain genera like Orthonema, Palaeostylus, Cerithioides and Knightella. They have a heliciform protoconch which is fundamentally different from the protoconch of the pseudozygopleurids (Ptenoglossa). The protoconch of the Pseudozygopleuridae is the essential apomorphy concerning the shell of the Ptenoglossa. 30 species are described as new (see Anhang A), 2 of which are Recent, 8 are from the Tertiary, 1 from the Cretacous, 13 from the Triassic, 1 from the Permian and 5 from the Carboniferous. Turritella hybrida MÜNSTER non DESHAYES gets the new name Zygopleura hybridissima nom. nov. 5 new genera are erected: Antiphora n. gen. (Triphoroidea, Tertiary), Eorex n. gen. (Triphoroidea, Tertiary), Atorcula n. gen. (Protorculidae, Triassic), Azyga n. gen. (Zygopleuridae, Triassic) and Striazyga n. gen. (Zygopleuridae, Triassic). Ampezzopleurinae n. subfam. is erected as subfamily of the Zygopleuridae. Nystiellinae CLENCH & TURNER is raised on family level (Nystiellidae). The subgenus Cerithiopsis (Vatopsis) GRÜNDEL is raised on genus level and is transferred from Cerithiopsidae H. & A. ADAMS to Eumetulidae GOLIKOV & STAROBOGATOV. Tembrockia GRÜNDEL is transferred from Cerithiopsidae to Eumetulidae. Variseila DOCKERY is transferred from Triforidae JOUSSEAUME to Eumetulidae. Ampezzopleura BANDEL is transferred from Protorculidae BANDEL to Zygopleuridae WENZ. Zygopleura tenuis (MÜNSTER) sensu Zardini is deemed to be the new nominal species Ampezzopleura tenuis BANDEL (type species of Ampezzopleura) for which a lectotype is designated. Teutonica SCHRÖDER is transferred from Cerithiopsidae to Zygopleuridae. Orthonema MEEK & WORTHEN is retransferred from Turritellidae LOVÉN to Acanthonematidae WENZ. Palaeostylus MANSUY is transferred from Procerithiidae COSSMANN to Acanthonematidae. Knightella LONGSTAFF is transferred from Pseudozygopleuridae KNIGHT to Acanthonematidae. Cerithioides HAUGHTON is transferred from Murchisoniidae KOKEN to Acanthonematidae WENZ. The systematic position of several other taxa has been critically revised. The generic position of several species is changed (see Anhang A "comb. nov.").

Description: thesis

Description: DFG, SUB Göttingen

Description: Klaus Bandel & Thorsten Kowalke: Systematic value of the larval shell of fossil and modern Vanikoridae, Pickworthiidae and the genus Fossarus (Caenogastropoda, Mollusca) … 3 ; R. Thomas Becker: Eine neue und älteste Glatziella (Clymeniida) aus dem höheren Oberdevon des Nordsauerlandes (Rheinisches Schiefergebirge) … 31 ; Glenn G. Rechner: Eine Dinoflagellaten-Zysten-Vergesellschaftung des tieferen Rupelium (Unter-Oligozän) aus transgressiven Ablagerungen nördlich von Altenhausen in Sachsen-Anhalt (Blatt 3733, Erxleben) … 43 ; Joachim Gründel: Zur Kenntis einiger Gastropoden-Gattungen aus dem französischen Jura und allgemeine Bemerkungen zur Gastropodenfauna aus dem Dogger Mittel- und Westeuropas … 69 ; Joachim Gründel: Heterostropha (Gastropoda) aus dem Dogger Norddeutschlands und Nordpolens. I. Mathildoidea (Mathildidae) … 131 ; Joachim Gründel: Heterostropha (Gastropoda) aus dem Dogger Norddeutschlands und Nordpolens. III. Opisthobranchia … 177 ; C. M. Hampton & J. E. Rae: Genesis of the fossiliferous Pleistocene Hima Limestone, western Uganda, as indicated by its isotopic composition … 225 ; Helmut Keupp: Anomal kiellose Hildoceratidae (= „Subfamilie Monestierinae SAPUNOV 1965“): Ursache taxonomischer Konfusionen (Ammonoidea, Toarcium) … 233 ; Helmut Keupp: Paläopathologische Analyse einer „Population“ von Dactylioceras athleticum (SIMPSON) aus dem Unter-Toarcium von Schlaifhausen/Oberfranken … 243 ; Rolf Kohring: Eischalen neognather Vögel aus dem mitteleozänen Geiseltal (Deutschland) … 269 ; Rolf Kohring: Eggshell Structure as Evidence in Avian Systematics - Preliminary Results … 281 ; Jürgen Kriwet: Beitrag zur Kenntnis der Fischfauna des Oberjura (unteres Kimmeridgium) der Kohlengrube Guimarota bei Leiria, Mittel-Portugal: 2. Neoselachii (Pisces, Elasmobranchii) ... 293 ; Thomas Schlüter: Validity of the Paratrichoptera - an extinct Insect Order related to the Mecoptera, Diptera, Trichoptera or Lepidoptera? Suggestions based on discoveries in the Upper Triassic Molteno Formation of South Africa … 303 ; Rolf Kohring: Bibliographie 1996, Institut für Paläontologie, Freie Universität Berlin … 313 ;

Description: thesis

Description: DFG, SUB Göttingen

Description: Contents ; List of Contributors ; Introduction ; I. General Problems of Sponge Biology. S. M. Efremova: Once more on the position among Metazoa - Gastrulation and germinal layers of sponges ; N. N. Marfenin: Sponges viewed in the light of up-to-date conception on coloniality ; A. V. Ereskovsky & G. P. Korotkova: The reasons of sponge sexual morphogenesis peculiarities II. Developmental Biology of Sponges. O. M. Ivanova-Kazas: Analysis of the sponges ontogeny at sexual reproduction ; R. P. Anakina: The cleavage specifity in embryos of the Barents Sea sponge Leucosolenia complicata Montagu (Calcispongiae, Calcaronea) ; L. V. Ivanova: New data about morphology and metamorphosis of the spongillid larvae (Porifera, Spongillidae). 1. Morphology of the free-swimming larvae ; L. V. Ivanova: New data about morphology and metamorphosis of the spongillid larvae (Porifera, Spongillidae). 2. The metamorphosis of the spongillid larvae ; L. V. Ivanova & V. V. Semenov: Feeding habits of the larvae of sponges ; N. A. Sizova & A. V. Ereskovsky: Ultrastructural peculiarities of the early embryogenesis in a White Sea sponge Halisarca dujardini (Demospongiae, Dendroceratida) ; III. Ecology of Sponges. R. P. Anakina & E. I. Slepian: Spiculas' malformations of freshwater sponges as indicators of water environment in St. Petersburg City ; A. S. Plotkin & A. V. Ereskovsky: Ecological aspects of asexual reproduction of the White Sea sponge Polymastia mammillaris (Demospongiae, Tetractinomorpha) in Kandalaksha Bay ; I. S. Smirnov & V. M. Koltun: Symbiosis of the antarctic sponge genus lophon (Porifera) and ophiuroid genus Ophiurolepis (Ophiuroidea, Echinodermata) ; IV. Palaeontology and Systematics. L. V. Bolshakova: Stromatoporoids - the fossil sponges ; E. V. Veinberg, 0. M. Khlystov, S. S. Vorobyova, E. G. Kornakova, 0. V. Levina, S. M. Efremova, & M. A. Grachev: Distribution of sponge spicules in sediments of the underwater Akademichesky ridge of Lake Baikal ; K. R. Tabachnik & C. Levi: Amphidiscophoran Hexasterophora (Part I & II) ;

Description: conference

Description: DFG, SUB Göttingen

Description: Von den bisher weitgehend unbearbeiteten, Oberkretazischen Gesteinsfolgen im Raum Santander (Provinz Kantabrien, Spanien) wurde der Zeitabschnitt Turon bis Unter-Coniac lithologisch, sedimentologisch sowie stratigraphisch (Bio-, Event-, Sequenzstratigraphie) detailliert bearbeitet. Die Sedimente eines gemischten, siliziklastisch/karbonatischen Systemes wurden in einem, durch starke synsedimentäre Tektonik geprägten, E-W-streichenden Meeresraum abgelagert, der nach Westen graduell in die flachmarine Asturianische Kreide überging und im Süden durch den, aus paläozoischem Basement bestehendenden Cabuemiga Rücken begrenzt war. Im Norden markierte das Liencres Hoch die Grenze. Dieser Sedimentationsraum repräsentierte einen eigenständigen Beckenbereich, für den die Bezeichnung Nordkantabrisches Becken (NKB) eingeführt wird. Das NKB entstand in der Unterkreide (Valangin/Hauterive) durch Blockrotation an E-W-streichenden Lineamenten. Strukturell trennt die N-S-streichende Rio Miera-Flexur im Osten das NKB vom Basko-Kantabrischen Becken. Proximale Sedimente sind durch das Auftreten von (glaukonitischen) Knollenkalken charakterisiert. Die eher distalen Ablagerungsräume zeichnen sich durch zyklische Kalk/Mergel-Wechselfolgen aus. Während regressiver Phasen treten Allochthonite auf (Calciturbidite). Im bearbeiteten Zeitraum Turon und Unter-Coniac führen möglicherweise fünf Phasen verstärkter differentieller Subsidenz (tektonische Aktivitätsphasen ?) zu Reliefakzentuierung und, damit einhergehend, zur Umgestaltung des Sedimentationsraumes. Besonders ein Ereignis im Unter-Coniac (deformis-Zone) kann offensichtlich in weiten Teilen Europas erkannt werden. Die biostratigraphische Gliederung wird mit Ammoniten und im höheren Ober-Turon und Unter-Coniac mit Inoceramen durchgeführt. Das basale Unter-Turon fehlt. Die Sedimentation setzt vermutlich erst in der höchsten devonense-Zvne des unteren Unter-Turon ein. Das obere Unter-Turon ist durch die Zone des Mammites nodosoides gekennzeichnet. Das Mittel-Turon kann in die Zonen des Kamerunoceras turoniense, Romaniceras kallesi, Romaniceras ornatissimum und Romaniceras deverianum untergliedert werden. Im Ober-Turon werden Faunenzonen ausgehalten (Assemblage Zones). Es können (in aufsteigender Reihenfolge) die AZ des Subprionocyclus neptuni/ Romaniceras deverianum, die AZ des Mytiloides incertus/Subprionocyclus neptuni und die AZ des Mytiloides scupini/Prionocyclus germari erkannt werden. Das Unter-Coniac wird in eine untere Zone des Cremnoceramus rotundatus und eine obere Zone des Cremnoceramus deformis unterteilt. Zehn Bio-Events und Akmen werden erkannt und auf ihr Potential für die regionale wie überregionale Korrelation geprüft. Dies sind das Mytiloides-Akme [Unter-Turon (?)]; das K. turoniense/Mytiloides-Event (turoniense-Zone), das R. kallesi-Event (kallesi-Zone), das R. ornatissimum-Event (ornatissimum-Zone), das R. Deverianum-Event (neptuni/deverianum- AZ), das Mytiloides incertus/Mieraster leskei (klein)-Event (incertus/neptuni-AZ), das M. Leskei (groß)-Event (scupini/germari-AZ), das Sternotaxis plana-Event (scupini/ germari- AZ), das Didymotis I-Event (scupini/ germari-AZ) und das Didymotis II-Event (Turon/Coniac-Grenze). Für eine Korrelation nach Deutschland oder England eignen sich besonders das turoniense/ Mytiloides-Event, das deverianum-Event sowie das incertus/leskei (klein)- und leskei (groß)-Event. Das plana-Event kann vermutlich nach Norddeutschland korreliert werden. Sechs sedimentäre Sequenzgrenzen (SB) werden im Zeitraum Turon bis Unter-Coniac erkannt und datiert. SB Tu 1 liegt vermutlich im Unter-Turon und kann wegen eines ausgeprägten Hiatus im Cenoman/Turon-Grenzbereich datiert werden. Die stratigraphischen Positionen der folgenden Sequenzgrenzen können wie folgt datiert werden: SB Tu 2: obere turoniense-Zone (Mittel-Turon), SB Tu 3: deverianum-Zont (höchstes Mittel-Turon), SB Tu 4: Top neptuni/deverianum- AZ (Ober-Turon), SB Tu 5: untere scupini/ germari-AZ (Ober-Turon), SB Co 1: höhere deformis-Zone des Unter-Coniac. Die Sedimentationszyklen werden als "3rd order cycles" sensu Haq et al. (1988) interpretiert. Die stratigraphische Position der Sequenzen werden unter kurzer Diskussion der jeweiligen regionalen Biostratigraphie mit sequentiellen Gliederungen für Tunesien, Spanien, Frankreich, Südengland und Deutschland (Westfalen, Niedersachsen, Sachsen) mit nur mäßigem Erfolg verglichen. Die "global cycle chart" erweist sich als Standard für untauglich. Schlüsselwörter: Nordkantabrien, Spanien, Nordkantabrisches Becken, Turon, Unter-Coniac, tektono-sedimentäre Entwicklung, Biostratigraphie, Eventstratigraphie, Sequenzstratigraphie, überregionaler Vergleich.

Description: The Lower Turonian to Lower Coniacian succession of the Upper Cretaceous series from the Santander area (Cantabria, Spain) was investigated in detail by means of lithology, bio-, event and sequence stratigraphy. The sediments of a mixed, siliciclastic/calcareous system were deposited in an E-W trending basin that was bordered to the South by the palaeozoic Cabuemiga High. The northern boundary formed the Liencres High, a palaeo-structure that had its position in the Bay of Biscay not far away from the present day shoreline. Towards the West, a connection to the shallower, Asturian Cretaceous basins existed. For this individual basin the term "North Cantabrian Basin" is suggested herein. It developed during the Early Cretaceous (Valanginian/Hauterivian) as a result of block rotation along E-W trending major faults. The NCB is structurally separated from the Basco-Cantabrian Basin by the N-S trending Rio Miera Flexure in the East. Proximal sediments are characterized by (glauconitic) nodular to massively bedded limestones. In distal environments, marl/limestone alternations accumulated. During phases of regression, allochthonites with only limited geographic extent were shed into the basin. Within the Turonian to Early Coniacian, five phases of accelerated, differential subsidence (tectonic phases ?) were recognized. Especially the Early Coniacian movement (deformis Zone) can be observed in wide parts of Europe. Biostratigraphic subdivision is mainly based on ammonites, and, in the Late Turonian and Early Coniacian, on inoceramids. Lower Lower Turonian strata are missing and sedimentation started presumably in the upper part of the Watinoceras devonense Zone of the early Early Turonian. The late Early Turonian is represented by the Mammites nodosoides Zone. The Middle Turonian can be subdivided into the zones of (in ascending order) Kamerunoceras turoniense, Romaniceras kallesi, Romaniceras ornatissimum, and Romaniceras deverianum. The Late Turonian is subdivided into assemblage zones (AZ). These are (in ascending order) the AZ of Subprionocyclus neptuni/Romaniceras deverianum, the AZ of Mytiloides incertus/Subprionocyclus neptuni and the AZ of Mytiloides scupini/Prionocyclus germari. The latter correlates with the scupini Zone of Germany. The Early Coniacian is characterized by a zone of Cremnoceramus rotundatus and a higher zone of Cremnoceramus deformis. Ten events are recognized and dated. These are the Mytiloides-acme [Lower Turonian (?)], the Kamerunoceras turoniense/Mytiloides event (turoniense Zone), the Romaniceras kallesi event (kallesi Zone), the Romaniceras ornatissimum event (ornatissimum Zone), the Romaniceras deverianum event (neptuni/deverianum AZ), the Mytiloides incertus/Micraster leskei (small) event (incertus/neptuni the Micraster leskei (large) event (scupini/germari AZ), the Sternotaxis plana event (scupini/germari AZ), the Didymotis I event (scupini/germari KL) and the Didymotis II event (Turonian/Coniacian boundary). These events can, to some extent, be used for interbasinal correlation. Especially the turoniense/Mytiloides, the deverianum, the plana and the Didymotis events can be correlated to northern Germany. The incertus/leskei (small) and the leskei (large) events can be traced to England. Six sedimentary sequence boundaries (SB) were recognized and dated. These are: SB Tu I : Lower Turonan, SB Tu 2: late turoniense Zone, SB Tu 3: deverianum Zone, SB Tu 4: top neptuni/deverianum KL, SB Tu 5: early scupini/germari AZ, SB Co 1: late deformis Zone. The sedimentary sequencec, delimited by the SBs, are interpreted to represent 3rd order cycles sensu Haq et al. (1988). The position of the sequences is (based on a brief discussion of the reginal biostratigraphic subdivisions) compared with cycle charts from Tunisia, Spain, France, southern England, and Germany (Westphalia, Lower Saxony, Saxony) with only limited results. The "global" cycle chart appears to be not helpful for detailed sequence correlation and should be abandoned as a standard.

Description: thesis

Description: DFG, SUB Göttingen

Description: At the beginning of Late Jurassic both the Lochen (LA) and the Cracow areas (CA) were palaeotopographic highs in an epicontinental basin located at the stable northern margin of the Tethyan Ocean. The topographically high position of the LA was probably caused by intensive carbonate production which proceeded on a small sea-floor bulge located close to the boundary between middle and lower parts of the low-angle carbonate ramp. Lack of deep structural control of this rise caused prograding facial unification during the Oxfordian and Kimmeridgian and led to gradual disappearance of the LA individuality in relation to the neighbouring areas. The topographical high of the CA resulted from anomalously low subsidence rate in comparison to the adjacent areas which has lasted at least for the whole Oxfordian. Low subsidence directly gave rise to the development of a barrier (so-called Cracovian Platform) which separated the interior basin in the north from the deeper parts of the basin in the south. Topography of the Polish part of epicontinental basin along the Czestochowa-Cracow line corresponds to the low-gradient rimmed carbonate shelf which graded laterally (to the northeast and east) into the low-angle carbonate ramp. Stratigraphic subdivision of Upper Jurassic strata is very precise in the LA and rather poor in the CA due to scarcity of ammonites in the massive facies which predominates in the latter area. However, ammonite fauna from both areas belongs to the same German-Polish Submediterranean Subprovince which allows to attempt the correlation of lithologies and determination of factors which controlled deposition. Both the studied areas show distinct differences in the development of carbonate buildups. In the LA the main components of carbonate buildups during whole Oxfordian and the Early Kimmeridgian were siliceous sponges and microbolites whilst in the CA the flourishing growth of microbolites and gradual decline of siliceous sponges domination took place during the Late Oxfordian. The sediment was initially diversified into the two varieties: that formed by siliceous sponges and the microbolites incipient rigid framework, and the soft mud. In such carbonate buildups stromatactis cavities might have developed even in early diagenesis due to internal erosion of the soft mud. The principal reason of the internal erosion was turbulent water flow through the sediment. However, in generally low-energy sedimentary environments such flow could be triggered by submarine gravity flows or strong bottom currents. Pseudonodular textures encountered in carbonate buildups in both the areas resulted from shallow-burial diagenesis. During the burial diagenesis some parts of the sediment has been disintegrated under the pressure of overlying strata owing to the existing open spaces and different susceptibility to compaction showed by the incipient rigid framework and the soft sediment. Deposition in the LA was controlled mainly by sea-level pulses and ecological factors. In the CA principal control was provided by subsidence rate supported by synsedimentary tectonics, sea-level changes and ecological factors. All these controlling factors were variable in time which provoked changes in carbonate production rates from intensive, aggradational growth of the buildups to drowning of the carbonate ramp and rimmed shelf. The drowning of carbonate ramp on which the LA was located took place at the Oxfordian/Kimmeridgian break. It is documented by spectacular development of redeposited pelagites of skeletal-calciturbidites type with abundant fragments of Saccocoma sp. which have appeared for the first time in mass quantities in the Upper Jurassic. By analogy, it can be inferred that in the CA similar Saccocoma-calciturbidites prove the drowning of rimmed shelf related to the same trangressive event at the Oxfordian/Kimmeridgian break.

Description: Zu Beginn des Ober-Jura waren das Lochengebiet (Schwäbische Alb) und der Raum Krakau (Südpolen) übereinstimmend Hochgebiete eines epikontinentalen Beckens auf dem passiven nördlichen Schelf der Tethys. Die topographische Hochposition des Lochengebietes war vermutlich durch eine hohe Karbonat-Produktion bedingt, welche auf einer schmalen submarinen Schwelle nahe dem Übergangsbereich zwischen unterem und mittlerem Abschnitt einer flach geneigten Karbonatrampe erfolgte. Während des Oxfordiums und Kimmeridgiums war die Lochenschwelle tektonisch inaktiv und ermöglichte einen zunehmenden Faziesausgleich mit den benachbarten Gebieten und führte dadurch zu einer successiven Aufgabe ihrer individuellen Entwicklung. Die Hochposition der Krakau-Region resultierte aus ihrer im Vergleich zur Umgebung ungewöhnlich geringen Subsidenzrate, welche mindestens während des gesamten Oxfordiums anhielt. Die geringe Subsidenz war unmittelbare Ursache für die Entwicklung einer Barriere (die sogenannte Krakau-Plattform), welche das seichtere Innenschelf-Becken im Norden von den tieferen Beckenanteilen im Süden trennte. Die Topographie des polnischen Anteils dieses epikontinentalen Beckens entsprach entlang der Czestochowa-Krakau-Linie einem „low-gradient rimmed carbonate shelf, der nach Nordosten und Osten lateral in eine flache Karbonatrampe überging. Die stratigraphische Gliederungsmöglichkeit der Ober-Jura-Schichfolge ist im Lochengebiet gut und feinauflösend, in der Krakau-Region dagegen, in der die Massenfazies vorherrscht, aufgrund der selteneren Ammonitenfunde zum Teil problematisch. Ungeachtet dessen, gehören die Ammoniten-Vergesellschaftungen beider Regionen derselben deutsch-polnischen, submediterranen Faunensubprovinz an und ermutigen zu einer Korrelation beider lithologischer Abfolgen und einer vergleichenden Abstraktion der Steuermechanismen für die Sedimentation. Beide Gebiete zeigen deutliche Unterschiede in der Entwicklung von karbonatischen Buildups. Im Lochen-Gebiet stellen während des Oxfordiums und Unter-Kimmeridgiums Kieselschwämme und Mikrobolithe die Hauptkomponenten der Riffstrukturen, während in der Krakau-Region die Bedeutung der Mikrobolithe und Kieselschwämme während des Ober-Oxfordiums successive abnimmt. Ursprünglich erfolgte eine Differenzierung der Riffstrukturen in einen autochthonen Hartsubstrat-Anteil, in dem Kieselschwämme und Mikrobolithe eine rigides Gerüst stellten, und in schlammiges Weichsubstrat. Innerhalb der Riffkörper konnten sich wohl frühdiagenetisch durch die interne Erosion der Schlamm-Anteile Stromatactis-Gefüge bilden. Grundsätzlich kann eine solche interne Erosion auf turbulente Porenwasserströme zurückgeführt werden. In den vorliegenden sedimentären Stillwasser-Milieus könnte ein solcher Porenwasserstrom durch submarine Schuttströme oder starke Bodenströmungen ausgelöst worden sein. Pseudonodulare Strukturen, wie sie in den Buildups beider Untersuchungsgebiete angetroffen wurden, werden durch eine flache Versenkungsdiagenese erklärt. Während dieser Vorgänge wurden unter dem Druck der Sedimentauflast aufgrund des vorhandenen, offenen Porenraumes und der unterschiedlichen Kompaktion von primär zementierten Riffkalken und des mergeligen Weichsubstrates Karbonatanteile gelöst. Das Sedimentationsgeschehen wurde in der Lochen-Region vor allem durch Meeresspiegel-Schwankungen und ökologische Parameter beeinflußt. In der Krakau-Region konnte als hauptsächlicher Kontrollfaktor die Subsidenzrate erkannt werden, in deren Gefolge synsedimentäre Tektonik, Änderungen von Meeresspiegel und der ökologischen Faktoren einhergingen. Veränderungen dieser Steuerfaktoren in der Zeit beeinflußten jeweils die Rate der Karbonatproduktion von intensiv (Aggradation der Buildups) bis zum Ertrinken der Karbonatrampe bzw. des Schelfrandes. Das Abtauchen der Karbonatrampe setzte in der Lochen-Region an der Oxfordium-Kimmeridgium-Wende ein. Es wird durch eine auffällige sedimentäre Entwicklung dokumentiert: Resedimentation pelagischer Kalke (skeletal calciturbidites), die häufig Saccocoma-Reste enthalten. Erste Massenvorkommen von Saccocoma treten in der Erdgeschichte im Oberjura auf. Ähnliche Saccoco/na-Kalkturbidite an der Oxfordium-Kimmeridgium-Grenze markieren in der Krakau-Region das Abtauchen des „rimmed shelf. Sie können auf dasselbe transgressive Ereignis zurückgeführt werden.

Description: thesis

Description: DFG, SUB Göttingen

Description: The present study considered calcareous nannofossils from material represented by outcrops of Flysch successions of the External Hellenides belt in the area of the Ionian Zone (I.Z.), northwestern Greece. The studied outcrops are located in Epirus mainland and the Ionian island Korfu. Three subdivisions have been traditionally in literature distinguished in the I.Z., the Internal, Middle and External (moving from east to the west), each of which was subsequently recognized in the Flysch deposits as well. Aim of the study was, a refinement of the current biostratigraphic resolution of the area through detailed taxonomic descriptions and consequently, a reliably better correlation of the investigated sedimentary deposits with the help of calcareous nannofossils. The biostratigraphic data were also processed semiquentitatively (frequency variations and distributions), in order to accurately determine important biohorizons. For this purpose, the nannofossils were studied under the LM and the SEM, from ten closely sampled sections representing clastic sequences of all the three subdivisions of the I.Z. The investigated sections are situated at about 39° northern mid latitudes, a fact which resulted to mixed nannoflora assemblages of low and high latitudes character. The sections are namely: Elatos, Korfovouni (Internal I.Z. subdivision), Kato Despotiko, Strouga Goumenou and Ekklisia (Middle I.Z. subdivision), lower and upper Argyrotopos, National Road, Monos and Anacharavi (External I.Z. subdivision). They were found to range in age from the latest Eocene to the Early Miocene. Based on the systematic palaeontology, 107 species of calcareous nannofossils were observed and documented in the studied material. Among them, a new species Rhabdosphaera epirotica sp. nov. was described, and four recombinations were proposed. Moreover, two calcareous dinoflagellate cysts, Cervisiella saxea and Obliquipithonella sp. were reported for the first time from the I.Z. in Greece. Despite the mid latitude palaeogeographic position of the sections, all the conventional calcareous nannofossil zonal markers for the Oligocene and Early Miocene were recorded, although some in fewer abundances than in low latitudes. Improving the biostratigraphic reliability, a new zonational scheme was here developed and proposed for the Oligocene to Early Miocene interval. It was mainly established on use of redefined biohorizons and composed of five zones and five subzones following below: 1. Latest Eocene: Ericsonia formosa Partial-range Zone, 2. Oligocene: llselithina fusa / Ericsonia formosa Concurrent-range Zone, Ericsonia formosa-Reticulofenestra umbilicus/R. hillae Interval Zone, Cyclicargolithus abisectus Partial-range Zone, including the subzones: Rhabdosphaera spp. Interval Subzone, and Sphenolithus predistentus Interval Subzone, Reticulofenestra scissura Interval Zone, including the Sphenolithus delphix Abundance Subzone, and 3. Earliest Miocene: Triquetrorhabdulus spp. Partial-range Subzone Sphenolithus conicus Interval Subzone. Based on a new biohorizon of the absolute First Occurrence (FO) of llselithina fusa, the Eocene/Oligocene (E/O) boundary was identified in the lower part of the Argyrotopos section. On the absence of disc-shaped discoasters, the I. fusa biohorizon represented a better approximation of the boundary, which was clearly correlated with the other studied sections of the three subdivisions of the I.Z. The Oligocene/Miocene (O/M) boundary was identified in the Monos section located in the Plataria syncline (External I.Z.), but Early Miocene strata were recorded in the Middle I.Z. as well. This boundary was placed at the Last Common Occurrence (LCO) biohorizon of the Reticulofenestra scissura. Moreover, six associate bioevents were reported near the O/M boundary, among them the highest occurrence of I. fusa, located above the boundary, in the Anacharavi section of Korfu island (western part of the External I.Z.). For the first time were evaluated reworked together with „autochton“ taxa of calcareous nannofossils in Greece. Maximum diversity values along each of the studied sections, have shown increased reworking and erosional processes in the Internal subdivision of the I.Z. than in the Middle and the External ones. This is interpreted to be connected with the higher tectonic instability along the Pindos thrust to the east, in relation to the central and western parts of the Ionian basin mainly during the Oligocene.

Description: Die der vorliegenden Arbeit zugrundeliegenden kalkigen Nannofossilien stammen von Flyschabfolgen der Externen Helleniden (Ionische Zone) Nordwest-Griechenlands.So wurden in die Untersuchung Aufschlüsse des Festlandes in Epirus und der Ionischen Insel Korfu aus dem stratigraphischen Intervall vom obersten Eozän bis zum untersten Miozän einbezogen. Die Ionische Zone (I.Z.) wird traditionell von Osten nach Westen in die Interne, Mittlere und Externe Subzone unterteilt. Diese Einteilung läßt sich auch auf die Flyschablagerungen übertragen. Ziel der Arbeit ist eine Verfeinerung der bestehenden Biostratigraphie durch detaillierte taxonomische Beschreibungen, um damit eine bessere Korrelation der untersuchten Ablagerungen mit Hilfe der kalkigen Nannofossilien zu erreichen. Mit einer halbquantitativen Erfassung der biostratigraphischen Daten (Häufigkeitsvariation und -Verteilung) gelingt es darüberhinaus, einzelne Biohorizonte genauer zu definieren. Zu diesem Zwecke wurde das kalkige Nannoplankton von zehn eng-beprobten Profilen aus klastischen Abfolgen aller drei Subzonen der I. Z. unter dem Licht- und Elektronenmikroskop (REM) untersucht. Die Profile im einzelnen sind: Elatos und Korfovouni (Interne Subzone), Kato Despotiko, Strouga Goumenou und Ekklisia (Mittlere Subzone), Unter bzw. Ober Argyrotopos, National Road, Monos und Anacharavi (Externe Subzone). Zur Ablagerungszeit befanden sich die untersuchten Profile in einer nördlichen Paläobreite um 39°, was zu einer gemischten Nannoflora aus charakteristischen Vertretern niedriger und höherer Breiten führte. In dem untersuchten Material konnten insgesamt 107 Spezies von kalkigem Nannoplankton gefunden und dokumentiert werden. Die Art Rhabdosphaera epirotica nov. sp.wird neu beschrieben und vier Rekombinationen werden vorgeschlagen. Darüberhinaus konnten zwei kalkige Dinoflagellatenzysten Cervisiella saxea und Obliquipithonella sp. zum ersten Mal in der I.Z. nachgewiesen werden. Trotz der paläogeographischen Position der Profile in mittleren Paläobreitenbereich konnten alle konventionellen Zonenleitformen des kalkigen Nannoplanktons für das Oligozän und das Untermiozän gefunden werden, einige davon jedoch in geringerer Häufigkeit als in den niedrigeren Breiten. Durch die Verbesserung der biostratigraphischen Genauigkeit wird hier ein neues mediterranes Zonenschema für das Oligozän und das Untermiozän entwickelt, das im wesentlichen auf neu definierten Biohorizonten basiert. Es enthält fünf Zonen und fünf Subzonen: 1. Jüngstes Eozän: Ericsonia formosa Partial-range Zone, 2. Oligozän: llselithina fusa/Ericsonia formosa Concurrent-range Zone, Ericsonia formosa-Reticulofenestra umbilicus/R. hillae Interval Zone, Cyclicargolithus abisectus Partial-range Zone, gegliedert in den Subzonen: Rhabdosphaera spp. Interval Subzone, und Sphenolithus predistentus Interval Subzone, Reticulofenestra scissura Interval Zone, die eine Subzone enthält: Sphenolithus delphix Abundance Subzone, und 3. Ältestes Miozän: Triquetrorhabdulus spp. Partial-range Subzone Sphenolithus conicus Interval Subzone. Mit dem ersten Auftreten (FO) von llselithina fusa wird ein neuer Biohorizont definiert, mit dem die Grenze Eozän/Oligozän (E/O) in dem unteren Teil des Argyrotopos-Profils nachgewiesen wird. Trotz der Abwesenheit von scheibenförmigen Discoasteriden läßt sich nun diese Grenze mit dem I. fusa-Biohorizont besser fassen und kann eindeutig mit den Profilen in den beiden anderen Subzonen der I.Z. korreliert werden. Die Oligozän/Miozän-Grenze (O/M) konnte im Monos-Profil der Plataria-Synklinale (Externe I.Z.) charakterisiert werden. Untermiozän ließ sich aber auch in der Mittleren Subzone nachweisen. Die Grenze O/M ist durch das letzte Vorkommen (LCO) von Reticulofenestra scissura bestimmt. Sechs assoziierte Bioevents fallen in diesen Grenzbereich, darunter im Anacharavi-Profil der Insel Korfu (Westteil der Externen Subzone) das jüngste Vorkommen von I. fusa, unmittelbar über der Grenze O/M. Zum erstem Mal für Griechenland konnten aufgearbeitete Taxa von kalkigen Nannofossilien zusammen mit den autochthonen Taxa nachgewiesen werden. Ein Vergleich der maximalen Diversitätswerte in den untersuchten Profilen zeigt eine signifikant höhere Aufarbeitungsrate in der Internen Subzone gegenüber der Mittleren und Externen Subzonen. Dieser Umstand dürfte mit der höheren tektonischen Instabilität entlang der Pindos-Decken-Front im Osten des Arbeitsgebietes Zusammenhängen.

Description: thesis

Description: DFG, SUB Göttingen

Description: Mit einer dreidimensionalen Vorwärtsmodellierung von Dichtestrukturen der Kruste und des oberen Mantels im Gebiet von 12°-35°S und 57°-79°W wird der regionale Trend des Schwerefelds und gleichzeitig das Geoid am aktiven Kontinentalrand Südamerikas zwischen 20° S und 29°S erklärt. Das Dichtemodell umfaßt die abtauchende Nazca-Platte, Teile des südamerikanischen Kratons, den Asthenosphärenkeil zwischen Unter- und Oberplatte und die Kruste der Zentralanden. Eine Vielzahl externer geowissenschaftlicher Randbedingungen schränkt die Dichteverteilung ein. Die Strukturierung der zentralandinen Kruste im Modell orientiert sich hauptsächlich an den Ergebnissen der Refraktionsseismik. Zur Ermittlung der Krustendichten wird eine druck- und temperaturabhängige Geschwindigkeits-Dichte-Beziehung (S. Sobolev) zur Anwendung gebracht. Neben der bekannten Berechnung der Schwerewirkung dreidimensionaler Dichteverteilungen erlaubt eine neuentwickelte Berechnung des Schwerepotentials nun auch die Modellierung des Geoids. Das Einbeziehen eines Referenzdichtemodells ermöglicht die Anpassung der berechneten Felder an die beobachteten Felder bei gleichzeitiger Verwendung von Absolutdichten. Verschiedene Dichtekontraste der abtauchenden Nazca-Platte gegenüber dem umgebenden Mantel sowie mögliche Dichtekontraste innerhalb des Slab, die sich aus Phasenumwandlungen der gesteinsbildenden Minerale ergeben, werden behandelt und ihre einzelnen Beiträge zum Schwerefeld und Geoid der zentralen Anden berechnet. Mit dem fertigen Gesamtmodell wird die Zusammensetzung des Schwerefeldes und des Geoids am aktiven Kontinentalrand Südamerikas analysiert und ihre Hauptbeiträge dargestellt. Die im Modell enthaltenen Strukturen erklären das regionale Schwerefeld und das Geoid vollständig. Daraus folgt, daß aus tieferliegenden Dichteinhomogenitäten, beispielsweise an der Grenze vom oberen zum unteren Mantel oder im unteren Mantel aufgrund einer möglichen isostatischen “in situ”-Kompensation keine weiteren Beiträge zu erwarten sind. Das Schwereminimum wird hauptsächlich durch eine bis auf 65km verdickte Kruste erklärt. Die Schweremaxima in der Küstenkordillere werden durch den Beitrag des Slab und eine Zone erhöhter Dichte in mittlerer Krustentiefe verursacht. Eine anomale VΡ-ρ-Beziehung unter dem rezenten Arc läßt dort partielle Aufschmelzung vermuten. Eine Untersuchung des Schwimmgleichgewichts des Modells ergibt isostatische Unterkompensation (= Massenüberschuß) im Bereich der Küstenkordillere und der Ostkordillere sowie isostatischen Ausgleich bis leichte Überkompensation im Bereich der Westkordillere und des Altiplano bzw. der Puna.

Description: A three-dimensional foreward modelling of the density structures of the crust and the upper mantle in the region between 12°-35°S and 57°-79°W explains both the regional trend of the gravity field and the geoid at the active continental margin of South America from 20°S to 29°S. The density model comprises the downgoing Nazca plate, parts of the South American craton, the asthenospheric wedge between lower and upper plate, and the crust of the Central Andes. A large number of external geoscientific boundary conditions constrains the density distribution. The Central Andean crust of the model is structured according to the results of refraction seismic studies. A pressure and temperature dependent velocity- density relation (S. Sobolev) is applied to determine densities within the crust. Apart from the well known calculation of the gravity effect of three-dimensional density distributions, a recently developped calculation of the gravity potential now allows the modelling of the geoid. Using absolute densities, the fitting of the calculated fields to the observed fields is realized by the application of a reference density model. Several density contrasts of the subducting Nazca plate against the surrounding mantle and possible density contrasts inside the slab resulting from mineral phase transitions are discussed and their particular contributions to the Central Andean gravity field and the geoid are calculated. Using the complete model, the composition of the gravity field and the geoid at the active continental margin of South America is analyzed and the main contributions are visualized. The model structures explain both regional gravity field and geoid completely. This implies that density inhomogeneities at greater depth than presented in the model, e. g. at the interface between the upper and the lower mantle or in the lower mantle are not expected to have effects at the surface due to possible isostatic “in situ” compensation. The gravity minimum is generally explained by a crust thickened to 65 km maximum. The gravity highs in the Coastal Cordillera are caused by the contribution of the slab and a zone of increased density in mid crustal layers. An anomalous VΡ-ρ- relation beneath the recent arc implies partial melt. The investigation of the isostatic state of the density model results in isostatic undercompensation (= mass surplus) in the region of the Coastal Cordillera und the Eastern Cordillera, and isostatic equilibrium to slight overcompensation in the Altiplano/Puna region.

Description: thesis

Description: DFG, SUB Göttingen

Description: Distribution of mineral assemblages in sediments of both shelf and continental slope of Vietnam is under consideration. Mineral provinces are recognized and their characteristics are given. Principal regularities of formation of mineral composition in marine sediments (with their supply provinces mainly located in the subequatorial belt) are shown on the basis of multivariate statistics methods (correlation, factor, cluster, regression and discriminant analyses). It is established that influence of climate on formation of the mineral assemblages is noticeable, but not determining.

Description: The collection of ferromanganese nodules at Naturhistoriska Riksmuseet, Stockholm, Sweden has been donated by Pr. Boström, K. and Ingri, J. from the Technical University of Lulea. They have been collected in the Bothnia Gulf, the Baltic Sea anfd the Barents sea from 1976 until 1985. In 1997 it is was put to the care custody of the Laboratory for Isotope Geology (LIG) of NRM. As part of the Access Project at LIG, Curt Boman has gone through the collection and established a database with detailed information about the samples it contains. Ferromanganese nodules typically display a rounded shape and are formed by redox processes at the interface between the seabed sediment and water. In addition to iron and manganese they also contain other metal elements. Nodules chemical composition reflects the substances found in the sediment to which they are associated. Since the nodules grow continuously, they reflect changes in the sedimentary environment chemistry on a yearly basis, which makes them very interesting as environmental archives. The nodules can be found locally in large quantities and due to their metal content they are also economically interesting as a source of raw materials.

Description: Using two cores from the eastern and western Pacific, we have attempted to better quantify tropical ocean temperatures during the last glacial in order to determine how this climatically-important region responds to large scale changes in climate forcing. By analyzing the oxygen isotopes of surface dwelling (G. sacculifer, G. ruber), thermocline dwelling (N. dutertrei, G. menardii, P. obliquiloculata) and sub-thermocline dwelling (G. inflata) planktonic foraminifera, both relative and absolute estimates of the changes in the temperature gradient over this depth interval have been made. Owing to poor carbonate preservation in the Holocene section of both cores, relative temperature estimates suggest only a slight glacial cooling (~2°C) at these locations, similar to that reported by CLIMAP [1976, 1981]. However, absolute temperature estimates determined from calcite-seawater paleothermometry indicate the eastern equatorial Pacific (EEP) was ~3°C cooler during the last glacial maximum (LGM), while the western equatorial Pacific (WEP) was ~4°C cooler. The upper water column appears to have been less stratified in the EEP, with a steeper thermocline, interpreted as indicating an increase in upwelling during the LGM. The WEP maintained a well developed mixed layer and deep thermocline, similar to today. These results are consistent with a variety of recent tropical temperature estimates for the LGM.

Description: In order to determine geochemical compositions of Late Cenozoic Arctic seawater, oxide fractions were chemically separated from 15 samples of hand-picked ferromanganese micronodules (50-300 mu m). The success of the chemical separation is indicated by the fact that 〉97% of the Sr in the oxide fraction is seawater-derived. Rare-earth element (REE) abundances of the Arctic micronodule oxide fractions are much lower than those of bulk Fe-Mn nodules from other ocean basins of the world (e.g., 33 vs. 145 ppm Nd), but the Arctic oxides are enriched in Ce relative to Nd (Ce-N/Nd-N=2.2+/-0.5) and have convex-upward, shale-normalized REE patterns (Nd-N/Gd-N=0.61+/-0.06, Gd-N/Yb-N = 1.5+/-0.2, Nd-N/Yb-N = 0.9+/-0.2), typical of other hydrogenous and diagenetic marine Fe-Mn-oxides. Bulk sediment samples from the central Arctic Ocean have REE abundances and patterns that are characteristic of those of post-Archean shale. Non-detrital fractions (calcite + oxide coatings) of Recent Arctic foraminifera have REE abundances and patterns similar to those of Recent foraminifera from the Atlantic Ocean. Electron microprobe analyses (n=178) of transition elements in 29 Arctic Fe-Mn micronodules from five different stratigraphic intervals of Late Cenozoic sediment indicate that oxide accretion occurred as a result of hydrogenetic and diagenetic processes close to the sediment-seawater interface. Transition element ratios suggest that no oxide accretion occurred during transitions from oxic to suboxic diagenetic conditions. Only K is correlated with Si and Al, and ratios of these elements suggest that they are associated with illite or phillipsite. Ca and Mg are correlated with Mn, which indicates variable substitution of these elements from seawater into the manganate phase. The geochemical characteristics of Arctic Fe-Mn micronodules indicate that the REEs of the oxide fractions were ultimately derived from seawater. However, because of minute contributions of Sr from siliciclastic detritus during diagenesis or during the chemical leaching procedure, Sr isotope compositions of the oxide fractions cannot be used to trace temporal changes in the Sr-87/Sr-86 ratio of Arctic seawater or to improve the chronostratigraphy.

Description: Together with foraminifers and ostracods, echinoderm remains are very frequent in Eemian sediments of the Dagebuell Well DA-1. The appearance of holothurian sclerites is particularly noteworthy. In the present study, remains of Holothuroidea from the European Pleistocene are described. These remains could be assigned to the Recent genus Psolus OKEN 1815. Furthermore, a short synopsis of disarticulate holothurian fossils in Holocene and Pleistocene sediments is given.

Description: Investigations of petrography, mineralogy, and chemical composition of gases and fluids in tuffs and lavas were carried out on samples dredged in the transition zone from the shelf and slope of Iceland to the Reykjanes Ridge. The samples were collected from the depths of 950-720 m during different expeditions of R/V Akademik Kurchatov and Mikhail Lomonosov. Mantle ultrabasite inclusions were first recognized in the region of Iceland. It can be assumed that they are related to eruptive structures formed on the ocean floor during Pliocene and are associated with the Iceland hot spot.

Description: Typical size of bubbles obtained from cavitation inception pressure measured in the surface layer of the Atlantic Ocean in situ aboard R/V Professor Vize in 1971 and Nerey in 1973 are reported. These results do not contradict ones of bubble size measurements using optical or acoustical techniques. Variability of bubble size is discovered and described. This variability is related to passing from one geographical region to another (from 68°55'S to 61°52'N), to changes in depth (from 5 to 100 m) and in day time, as well as to spatial fluctuations within an aquatic area. It is suggested that, in addition to wave breaking, there is another source of bubbles at depth 10-20 m that associates with hydrobiological processes.

Description: Features of spatial variability of hydrogen sulfide in the northeastern part of the Black Sea are estimated. Some technical aspects of H2S concentration determination in the anoxic zone are discussed: in its upper part at H2S concentration 〈30 µmol/l, the photometric method is recommended, while for deeper layers the iodometric method should be used. With linearity of vertical distribution of hydrogen sulfide and ammonium taken into account their vertical gradients are estimated as 0.49+/-0.04 µmol/m and 0.19+/-0.06 µmol/m respectively. It is shown that the upper boundary of the H2S layer corresponds to the isopycnal surface with Sigma_t = 16.19+/-0.05 arbitrary units. Special attention is paid to relationship of hydrogen sulfide distribution with hydrophysical features in the region under study, in particular in the coastal zone. It is shown that hydrodynamic conditions control spatial distribution of hydrogen sulfide. On the basis of isopycnal treatment of the H2S field existence of a coastal convergence zone is proved, and peculiarities are recognized of vertical circulation in the main Black Sea gyre and coastal anticyclonic eddies; here hydrogen sulfide serves as a tracer of hydrophysical mixing processes.

Description: The climatic deterioration related to the onset of Northern Hemisphere glaciations (circa 2.52 Ma BP) must have lead to reorganization and relocation of species associations and may have enhanced species turnover. The present study investigates how this deterioration affects the dinoflagellate cyst and acritarch assemblages from two locations, DSDP Site 607 (North Atlantic) and the Singa section (southern Italy). The records from these locations cover the interval from 2.8 to 2.2 Ma with at least a 5 ka resolution and they have been correlated to the Milankovitch periodicities on a cycle to cycle basis by means of integrated high resolution stable isotope, calcium carbonate, foraminiferal, palynological and magnetostratigraphical datasets. In the present study this high resolution stratigraphic framework is used for a detailed correlation of events occurring in each of the depositional sequences. It also enables further assessment of the palaeoenvironmental preferences of some dinoflagellate cyst forms. Comparison of the two palynological records reveals a close correspondence in the timing of major assemblage changes and extinction events, confirming their Milankovitch cycle based correlation. A close link between periods of Northern Hemisphere cooling (at oxygen isotope stages 110, 104 and 100-96) and increased dinoflagellate cyst turnover appears to be present for both DSDP Site 607 and the Singa section. The turnover events can also be recognized in the records of planktic foraminifera and calcamous nannoplankton. Comparison of the Singa section with Site 607 and with other time equivalent marine palynological data sets, shows that some oceanic taxa respond similarly over a large area. The biostratigraphical implications are discussed. Notably the last occurrence of Invertocystu lucrymosa appears to be a valuable marker for isotope stage 110 in the Mediterranean and North Atlantic.

Description: The availability of CaCO3 and 3He content results for core TT 13-72 from 4.3 km depth in the equatorial Pacific (Marcantonio et al., 1996, doi:10.1038/383705a0) allows the magnitude of the excess (i.e., over ambient) CaCO3 dissolution at the onset of marine glacial stages 10, 8, and 6 to be estimated. These three events are remarkably similar; during each an integrated loss of about 28 g CaCO3 per cm² occurred. While the magnitude of this loss is consistent with that expected from the interglacial to glacial pH shifts reconstructed based on boron isotope measurements on benthic foraminifera (Sanyal et al., 1995, doi:10.1038/373234a0), measurements at a number of other locations and water depths will be required before this approach can be used to evaluate the global toll of these dissolution events.

Description: Eocene-Oligocene radiolarians from Ocean Drilling Program Sites 699, 702, and 703, Leg 114 of the Subantarctic Atlantic were examined in order to extend the tripartite zonation for the recovered cores based on results of similar analysis of Leg 120 submarine sediments from the Indian Ocean. Correlation of the two oceans is made by examining 23 biohorizons and the three zones, Eucyrtidium spinosum, Axoprunum irregularis, and Lychnocanoma conica, in ascending stratigraphic order. One new species, Eucyrtidium nishimurae, is described.

Description: Fluctuations in oxygen (d18O) and carbon (d13C) isotope values of benthic foraminiferal calcite from the tropical Pacific and Southern Oceans indicate rapid reversals in the dominant mode and direction of the thermohaline circulation during a 1 m.y. interval (71-70 Ma) in the Maastrichtian. At the onset of this change, benthic foraminiferal d18O values increased and were highest in low-latitude Pacific Ocean waters, whereas benthic and planktic foraminiferal d13C values decreased and benthic values were lowest in the Southern Ocean. Subsequently, benthic foraminiferal d18O values in the Indo-Pacific decreased, and benthic and planktic d13C values increased globally. These isotopic patterns suggest that cool intermediate-depth waters, derived from high-latitude regions, penetrated temporarily to the tropics. The low benthic d13C values at the Southern Ocean sites, however, suggest that these cool waters may have been derived from high northern rather than high southern latitudes. Correlation with eustatic sea-level curves suggests that sea-level change was the most likely mechanism to change the circulation and/or source(s) of intermediate-depth waters. We thus propose that oceanic circulation during the latest Cretaceous was vigorous and that competing sources of intermediate- and deep-water formation, linked to changes in climate and sea level, may have alternated in importance.

Description: Two recently drilled Caribbean sites contain expanded sedimentary records of the late Paleocene thermal maximum, a dramatic global warming event that occurred at ca. 55 Ma. The records document significant environmental changes, including deep-water oxygen deficiency and a mass extinction of deep-sea fauna, intertwined with evidence for a major episode of explosive volcanism. We postulate that this volcanism initiated a reordering of ocean circulation that resulted in rapid global warming and dramatic changes in the Earth's environment.

Description: A simple, untuned "constant sedimentation rate" timescale developed using three radiometric age constraints and eleven d18O records longer than 0.8 Myr provides strong support for the validity of the SPECMAP timescale of the late Quaternary (Imbrie et al., 1984). In particular, the present study independently confirms the link between major deglaciations (terminations) and increases in northern hemisphere summer radiation at high latitudes and shows that this correlation is not an artifact of orbital tuning. In addition, the excess ice characteristic of late Quaternary "100-kyr" climate cycles typically accumulates when July insolation at 65°N has been unusually low for more than a full precessional cycle, or 〉21 kyr, and once established does not last beyond the next increase in summer insolation. Thus, the timing of the growth and decay of large 100-kyr ice sheets, as depicted in the deep sea d18O record, is strongly (and semipredictably) influenced by eccentricity through its modulation of the orbital precession component of northern hemisphere summer insolation.

Description: New heat flow observations have been made in the Iberia abyssal plain off the Galicia margin along the transeat of Ocean Drilling Program Leg 149 drill sites. in order to investigate the nature of this unusually wide and deep continet-ocean transition region. Our results indicate the presence of three separate zones. Average values of 47.5 +/- 3 mW/m in the westernmost zone III agree with predictions of standard oceanic lithospheric models for its estimated age of 126 Ma. In contrast, the heat flow within zone II is 5-15 mW/m higher than predicted. assuming that the mantle heat flow remains constant across the basin. This region of high values is coincident with the location of a major intra-crustal “S”-type reflector east of ODP Site 900. and the anomaly is consistent with the presence of 2-3 km of primarily upper continental crust above the reflector, with concentrations of radiogenic components similar to those from granodiorite samplles dredged off Galicia Bank. It is not, however, consistent with the low values of heat production measured on gabbroic sanhples from its western end at ODP Site 900. In zone I, detailed measurements across the tilted fault block south of ODP Site 901 show consistent variations which closely match predictions due to the effects of basement structure and sediment deposition. There is no evidence for variations due to vertical convective transport along the dipping basement fault block. Once corrected for these variations. measurements in zone I yield average values that agree quite well with previous measurements across Calicia Bank. indicating no systematic landward increase in heat flow with decreasing amounts of continental, extension.

Description: Rapidly deposited Thalassionema-Thalassiothrti pennate diatom oozes previously have been described in Upper Miocene-Lower Pliocene sediment beneath the frontal boundary of the eastern equatorial Pacific. Here we document a new occurrence of Thalassionema-Thalassiothrix ooze in Upper Miocene-Lower Pliocene sediment beneath the frontal boundary of the subarctic North Pacific. The ooze is a 6 m interval of siliceous sediment at Ocean Drilling Program (ODP) sites 885/886 that was rapidly deposited between approximately 5.0 and 5.9 Ma. Bulk sediment in this interval may contain greater than 85% pennate diatom tests. There are also abundant laminae and pockets that are composed entirely of Thalassionema and Thalassiothrix diatoms. The presence of a rapidly deposited ooze dominated by pennate diatoms indicates unusual past conditions in the overlying surface waters. Time coincident deposition of such oozes at two distinct frontal boundary locations of the Pacific suggests that the unusual surface water conditions were causally linked to large-scale oceanographic change. This same oceanographic change most likely involved (1) addition of nutrients to the ocean, or (2) redistribution of nutrients within the ocean. The occurrence and origin of pennate diatom oozes may be a key component to an integrative understanding of late Neogene paleoceanography and biogeochemical cycling.

Description: Oxygen-isotope analyses of planktonic foraminifera from 57 western Pacific deep-sea cores are compared for the Holocene and the Last Glacial Maximum (LGM). Carbonate dissolution, sedimentation rates/bioturbation, sample density, and vital effects are assessed before the sea-surface salinity signal of these records is reconstructed. Average glacial-interglacial Delta delta18O values in the western Pacific are found to be close to those in the Atlantic Ocean (1.76 ‰ in the Pacific compared to 1.80 ‰ in the Atlantic), questioning previous suggestions of a larger salinity difference between the Atlantic and the Pacific oceans during the LGM. During the LGM, sea-surface salinity was higher in the western Pacific than today (by 〉~1 ‰), implying that evaporation minus precipitation was higher all over the region. The minimum change in sea-surface salinity occurred around the equator at the core of the Western Pacific Warm Pool. Holocene high-amplitude, high-frequency fluctuations in planktonic delta18O records north and south of the present limits of the Western Pacific Warm Pool are indicative of sea-surface temperature and/or sea-surface salinity variations related to its expansion and contraction at the scale of thousands of years. Such high-amplitude, high-frequency fluctuations at the edge of the WPWP are best documented in the delta18O signal of ODP Hole 828A offshore Vanuatu, so far the best high-resolution record for the western Pacific.

Description: Sapropels -organic-matter rich layers- are common in Neogene sediments of the eastern Mediterranean Sea. The formation of these layers has been attributed to climate-related increases in organic-matter production (Calvert et al., 1992, doi:10.1038/359223a0; Rossignol-Strick et al., 1982, doi:10.1038/295105a0; Rohling, 1994, doi:10.1016/0025-3227(94)90202-X) and increased organic-matter preservation due to oxygen depletion in more stagnant bottom waters (Rossignol-Strick et al., 1982, doi:10.1038/295105a0; Rohling, 1994, doi:10.1016/0025-3227(94)90202-X). Here we report that eastern Mediterranean Pliocene sapropels (Emeis et al., 1996, doi:10.2973/odp.proc.ir.160.102.1996) contain molecular fossils of a compound (isorenieratene) known to be synthesized by photosynthetic green sulphur bacteria, suggesting that sulphidic (euxinic) -and therefore anoxic- conditions prevailed in the photic zone of the water column. These sapropels also have a high trace-metal content, which is probably due to the efficient scavenging of these metals by precipitating sulphides in a euxinic water column. The abundance and sulphur-isotope composition of pyrite are consistent with iron sulphide formation in the water column. We conclude that basin-wide water-column euxinia occurred over substantial periods during Pliocene sapropel formation in the eastern Mediterranean Sea, and that the ultimate degradation of the increased organic-matter production was strongly influential in generating and sustaining the euxinic conditions.

Description: Shipboard analysis of the 1183-m sedimentary section recovered at Site 918 in the Irminger Basin during Ocean Drilling Program Leg 152 revealed material of glacial origin (diamictons, ice-rafted debris (IRD) and dropstones) as deep as 543 m below sea floor (bsf). The sediment containing the deepest dropstone was biostratigraphically dated shipboard as approximately 7 Ma, pushing back the date for the onset of glaciation on southern Greenland by 5 Ma. Thin layers of fine sand were found as much as 60 m deeper in the core, raising the possibility of an even earlier date for glaciation. To determine the sedimentary history of these deeper sand layers, the surface textures on quartz grains from eleven cores bracketing the interval of interest were analyzed by scanning electron microscope. The results suggest that the grains in the 60-m interval below the deepest dropstone have a glacial history. At that level, an 11 -Ma Sr-isotope date was obtained from planktonic foraminifers. This late Miocene timing is supported biostratigraphically by both nannofossil and foraminifer assemblages, indicating a new minimum age for the onset of glaciation on southern Greenland and in the North Atlantic.

Description: High-resolution records (2 7 kyr) of Upper Pliocene Discoaster abundances obtained from six ODP/DSDP sites are assessed independently using oxygen isotope stratigraphy. Four Atlantic Ocean sites (DSDP Sites 552 and 607, and ODP Sites 659 and 662) comprise a transect from 56°N to 1°S and provide a record of latitudinal variations in Diseoaster biogeography. Low-latitude sites in the Atlantic (ODP Site 662), Pacific (ODP Site 677), and Indian (ODP Site 709) oceans provide additional information about variability in Discoaster abundance patterns within the equatorial region. A common chronology, based on the astronomical time scale developed for ODP Site 677, has been established for all the sites. By integrating oxygen isotope data and Discoaster abundance records at each site we are able to independently evaluate the temporal and spatial distribution of D. brouweri and D. triradiatus in the 500 kyr prior to the extinction of the discoasters near the base of the Olduvai subchron. Major decreases in abundance are evident during some of the more intense late Pliocene glacial events. In particular, glacial isotope stages 82, 96, 98 and 100 are associated with distinct abundance minima. At these times, large-scale changes in surface hydrographic conditions appear to have suppressed Discoaster numbers on a global scale. The increase in abundance of D. triradiatus, which precedes the extinction of the discoasters by around 200 kyr, may also be related to the intensification of environmental pressures that accompanied the build-up of Northern Hemisphere ice sheets during the late Pliocene. In spite of contrasting geographic and oceanographic settings, the various D. brouweri and D. triradiatus records are remarkably similar. This demonstrates that the acme and extinction events are excellent biostratigraphic datums. The simultaneous extinction of D. brouweri and D. triradiatus at 1.95 Ma were synchronous events at both a regional scale within the Atlantic, and on a global scale between the three major oceans. However, the start of the D. triradiatus acme appears to have been diachronous, occurring some 40 kyr earlier in the Atlantic than in the Indo-Pacific, and hence the stratigraphic usefulness of this datum is regional rather than global.

Description: We evaluated the response of eastern equatorial Pacific upper water column hydrography to the Panama seaway closure and the initiation of large-scale northern hemisphere glaciation, The d18O gradient between Globorotalia tumida and Globigerinoides sacculifer indicates a general shoaling of the thermocline between 4.2 and 3.0 Ma which may be related to a recorded decrease in southeast trade wind strength. The d13C gradients suggest that surface water nutrient concentrations have increased during the last 5 Myr and that upwelling intermediate waters began to change sources at ~3.2 Ma. Changes in the trans-Pacific east-west temperature and nutrient gradients at 4.0 and 1.5 Ma are coincident with the seaway closure and a major phase of northern hemisphere glaciation. Changes in the sensitivity of surface circulation to Milankovitch forcing, d18O records linearly related to orbital variations only after 3.2 Ma, are associated with the seaway closure. Pleistocene initiation of 100 and 41 kyr cycles in the thermocline depth proxy may suggest that the hydrographic response to Milankovitch forcing is enhanced by air-sea interactions which maintain the relatively steep Pleistocene trans-Pacific gradients. The d13C records are dominated by the 41 kyr period and are usually coherent with high-latitude climate, suggesting that associated changes in the global carbon reservoir dominate the tropical d13C signals.

Description: Total dissolvable iron (TDFe), particulate iron (PFe) and hydrogen peroxide (H2O2 measurements were performed along a N-S transect in the upper 250 m in the Southern Ocean (62°00E/66°42S - 49°00S, ANTARES II cruise, February 1994). TDFe was organically extracted (APDC/DDDC-chloroform) and analysed by Graphite Furnace Atomic Absorption Spectrometry (GFAAS), PFe was analysed by GFAAS following a strong mixed-acid leach, and H2O2 was analysed on board by fluorometry. The respective detection limits are equal to 0.13 nmol/kg, 0.02 nmol/kg, and 3.0 nmol/kg. TDFe concentrations vary from 0.4 to 6.2 nmol/kg and profiles are not completely depleted in the surface. PFe concentrations vary from 0.02 to 0.2 nmol/kg. Iron/carbon (Fe/C) uptake ratios for phytoplankton were calculated either from seawater or particle measurements. They are variable along the transect but are consistent when they could be compared. All the observed ratios are within the range of values proposed for the Fe/C uptake ratios by phytoplankton. Using our uptake ratio calculated in the Permanent Open Ocean Zone (4 x 10**?6 mol/mol), we estimate that the primary production which can be supported by the iron input flux into the surface waters is two times higher than the measured primary production in the same area. In the surface waters, H2O2 concentrations vary from 5.0 to 19.7 nmol/kg. Such low concentrations are due to strong vertical mixing, low dissolved organic matter concentrations and the latitude of the site.