Reconstruction of Late Bajocian - Bathonian marine palaeoenvironments using carbon and oxygen isotope ratios of calcareous fossils from the Polish Jura Chain (central Poland).

Joachimski M, Wierzbowski H (2007)

Publication Type: Journal article, Original article

Publication year: 2007

Journal

Palaeogeography, Palaeoclimatology, Palaeoecology Elsevier

Publisher: Elsevier

Book Volume: 254

Pages Range: 523-540

DOI: 10.1016/j.palaeo.2007.07.010

Abstract

Oxygen and carbon isotope analyses were carried out on Upper Bajocian - Bathonian calcitic belemnite rostra and oyster shells as well as aragonitic ammonite, nautiloid and trigoniid shells from the "Ore-bearing Cze{ogonek}stochowa Clay Formation" in south-central Poland. All samples were studied by means of cathodoluminscence microscopy, trace element, X-ray, and scanning electron microscope (SEM) analysis in order to select best-preserved material. SEM studies allowed classifying some aragonitic ammonite and nautiloid shells (> 99% aragonite) as diagenetically altered. Average δ¹⁸O values of oysters, belemnites and trigoniids translate into relatively low palaeotemperatures of 10.1, 9.2 and 7.4 °C, respectively. The comparable δ¹⁸O values of bivalves and belemnites indicate that belemnites had a nectobenthic lifestyle and did not record surface water temperatures. The ammonite fauna is interpreted to have been nektonic, however, palaeotemperatures derived from ammonite δ¹⁸O (around 18.6 °C) may be overestimated due to a lower, than normal marine, salinity of surface waters. The reduced salinity is inferred as well from sedimentological observations and faunal composition. The obtained δ¹⁸O values indicate cool climatic conditions during the Late Bajocian-Bathonian in south-central Poland, which may have been linked with the occurrence of a cold climatic episode. Despite the fact that all studied shells were not precipitated in carbon isotope equilibrium with ambient waters, the δ¹³C shell values enabled us to roughly estimate isotope composition of dissolved inorganic carbon (DIC) in the Late Bajocian-Bathonian sea of south-central Poland. Water δ¹³CDIC values calculated from ammonite δ¹³C are lower in comparison to δ¹³CDIC values calculated from oyster and belemnite carbon isotope ratios, which in conjunction with ammonite δ¹⁸O values indicates lower salinity of surface or shallow near-coastal waters. © 2007 Elsevier B.V. All rights reserved.

Authors with CRIS profile

Michael Joachimski Lehrstuhl für Geologie (Exogene Dynamik)

Involved external institutions

Polska Akademia Nauk (PAN) / Polish Academy of Sciences

Poland (PL)

How to cite

APA:

Joachimski, M., & Wierzbowski, H. (2007). Reconstruction of Late Bajocian - Bathonian marine palaeoenvironments using carbon and oxygen isotope ratios of calcareous fossils from the Polish Jura Chain (central Poland). Palaeogeography, Palaeoclimatology, Palaeoecology, 254, 523-540. https://doi.org/10.1016/j.palaeo.2007.07.010

MLA:

Joachimski, Michael, and Hubert Wierzbowski. "Reconstruction of Late Bajocian - Bathonian marine palaeoenvironments using carbon and oxygen isotope ratios of calcareous fossils from the Polish Jura Chain (central Poland)." Palaeogeography, Palaeoclimatology, Palaeoecology 254 (2007): 523-540.

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