Nauki Ścisłe i Nauki o Ziemi

Acta Geologica Polonica

Zawartość

Acta Geologica Polonica | 2022 | vol. 72 | No 2 |

Abstrakt

Upper Miocene (~6 Ma) sediments from a north-south transect of Ocean Drilling Program Holes 848B, 849B, 850B, 851B across the equator in the Eastern Pacific Ocean record an episode of unusual skeletal variability associated with the silicoflagellate Bachmannocena diodon subsp. nodosa (Bukry) Bukry, 1987. Skeletons in this plexus persisted for between 55,000 and 75,000 years and include an arch across a 2-sided basal ring, a highly unusual morphology for the genus. Groups of skeletal morphotypes were common within the plexus episode, and occur in a systematic sequence that is consistent between sites. As a result of this study, silicoflagellates previously placed in the genus Neonaviculopsis Locker and Martini, 1986 are now considered part of the Bachmannocena diodon subsp. nodosa plexus.
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Autorzy i Afiliacje

Adrianna Szaruga
1
Kevin McCartney
2
Jakub Witkowski
1

  1. Institute of Marine and Environmental Sciences, University of Szczecin, Mickiewicza 16a, 70-383 Szczecin, Poland
  2. Department of Environmental Studies and Sustainability, University of Maine at Presque Isle, Presque Isle, ME 04769 USA

Abstrakt

Upper Turonian to lower Coniacian marls of the Strehlen Formation of the Graupa 60/1 core were investigated for their foraminiferal content to add stratigraphical and palaeoenvironmental information about the transitional facies zone of the Saxonian Cretaceous Basin. Further comparison with foraminiferal faunas of the Brausnitzbach Marl (Schrammstein Formation) were carried out to clarify its relationship to the marls of the Graupa 60/1 core. Tethyan agglutinated marker species for the late Turonian to early Coniacian confirm the proposed age of the marls of the Graupa 60/1 core and the Brausnitzbach Marl. The palaeoenvironment of the marls reflects middle to outer shelf conditions. The maximum flooding zones of genetic sequences TUR6, TUR7 and CON1 could be linked to acmes of foraminiferal species and foraminiferal morphogroups. In general, a rise of the relative sea-level can be recognised from the base to the top of the marls of the Graupa 60/1 core. While agglutinated foraminiferal assemblages suggest a generally high organic matter influx and variable but high productivity in the Graupa 60/1 core, the Brausnitzbach Marl deposition was characterized by moderate productivity and a generally shallower water depth.
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Autorzy i Afiliacje

Richard M. Besen
1
Mareike Achilles
2
Mauro Alivernini
2
Thomas Voigt
2
Peter Frenzel
2
Ulrich Struck
3 4

  1. Freie Universität Berlin, Institut für Geologische Wissenschaften, Malteserstraße 74-100, 12249 Berlin, Germany
  2. Friedrich Schiller University of Jena, Institute of Earth Sciences, Burgweg 11, 07749 Jena, Germany
  3. Freie Universität Berlin, Institut für Geologische Wissenschaften, Malteserstraße 74-100, 12249 Berlin
  4. Museum für Naturkunde Berlin, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, Germany

Abstrakt

We document an upper upper Albian ( Mortoniceras rostratum Zone) cephalopod assemblage from Clansayes (Drôme, south-eastern France). Although fossils are rare in local exposures and in the single sampled level, a decade of intensive fossil collecting yielded 290 ammonite and 5 nautilid specimens. In total, we describe 1 species of nautilid and 24 species (within 17 genera) of ammonites, including 13 heteromorphs. Only two of these ammonite taxa were previously recorded from the upper upper Albian at Clansayes, which demonstrates the value of this fauna with regard to taxonomy, palaeobiology and palaeobiogeography. Based on morphological and biometric analyses performed on an extensive material (104 specimens), we discriminate two species for the heteromorphic ammonite genus Mariella Nowak, 1916 within the Mortoniceras rostratum Zone. In addition, we investigate shell chirality patterns in Mariella from the late Albian of southern France. Upon comparison of the Clansayes material with older material from the immediately underlying upper Albian Mortoniceras fallax Zone at the neighbouring Salazac locality, we identify an increase in the proportion of sinistral specimens. This observed increase in the frequency of sinistral Mariella specimens may hypothetically be part of a global evolutionary pattern, considering that nearly all documented younger Cenomanian Mariella (and more generally Cenomanian turrilitids) are sinistral.
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Autorzy i Afiliacje

Romain Jattiot
1
Jens Lehmann
1
Benjamin Latutrie
2
Amane Tajika
3 4
Emmanuelle Vennin
5
Pauline Vuarin
6
Arnaud Brayard
5
Emmanuel Fara
5
Vincent Trincal
7

  1. Fachbereich 5 Geowissenschaften, Universität Bremen, Klagenfurter Strasse 4, 28357, Bremen, Germany
  2. La Grange, 9003 En Cros, route de Garrigues, 81500, Lavaur, France
  3. Division of Paleontology (Invertebrates), American Museum of Natural History, Central Park West 79th Street, New York, NY, 10024, USA
  4. University Museum, University of Tokyo, Hongo 7‐3‐1, Bunkyo‐ku, Tokyo, 113‐0033, Japan
  5. UMR CNRS 6282 Biogéosciences, Université Bourgogne Franche-Comté, 6 Boulevard Gabriel, F-21000 Dijon, France
  6. Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR 5558, F-69622 Villeurbanne, France
  7. LMDC, INSAT/UPS Génie Civil, 135 Avenue de Rangueil, 31077 Toulouse cedex 04, France

Abstrakt

Compositional and textural data are presented for zircon, secondary Zr-silicates, catapleiite and elpidite in a peralkaline granite from the Ilímaussaq complex, south Greenland. The zircon is essentially stoichiometric, with (Zr + Hf + Si) = 1.96–1.98 a.p.f.u. The secondary Zr-silicates show a wide range of Zr/Si atomic ratios (0.13–0.79). The catapleiite varies from close to stoichiometric to a Na-depleted type showing cation deficiency (5.2–5.8 a.p.f.u.). Elpidite shows similar variations (7.2–9.0 a.p.f.u.). Textural relationships between the Zr phases are interpreted to show that magmatic zircon interacted with hydrous fluids exsolved from the magma to form the secondary Zr-silicates. Formation of catapleiite was late‑magmatic, in equilibrium with a Na-Sibearing fluid. This was followed by the crystallization of elpidite, the fluid having a different Na/Si ratio. Both catapleiite and elpidite experienced Na-loss during late-stage hydrothermal alteration.
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Autorzy i Afiliacje

Małgorzata Cegiełka
1 2
Bogusław Bagiński
1
Ray Macdonald
1 3
Harvey E. Belkin
4
Jakub Kotowski
1
Brian G.J. Upton
5

  1. Department of Geochemistry, Mineralogy and Petrology, Faculty of Geology, University of Warsaw, ul. Żwirki i Wigury 93, 02-089 Warsaw, Poland
  2. Institute of Geological Sciences, Polish Academy of Sciences, Research Centre in Warsaw, ul. Twarda 51/55, 00-818 Warsaw, Poland
  3. Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
  4. 11142 Forest Edge Drive, Reston, VA 20190, USA
  5. Grant Institute, University of Edinburgh, James Hutton Rd., Edinburgh EH9 3FE, UK

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