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Magnetic stratigraphy, stable isotopes and chemostratigraphy in the Upper Berriasian of Rówienka section (Western Tatra Mts., Fatric succession, Poland): Towards a consistent model of Late Berriasian palaeoenvironmental changes in the Western Tethys
Jacek Grabowski, Damian Gerard Lodowski, Johann Schnyder, Katarzyna Sobień, Leona Chadimova, Andrzej Pszczółkowski, Leszek Krzemiński, Petr Schnabl

Building: Muséum d'Histoire Naturelle de Genève
Room: Amphithéâtre
Date: 2018-12-06 05:00 PM – 05:20 PM
Last modified: 2018-12-01

Abstract


The results of new palaeoenvironmental research in the Carpathians (Rówienka, Fatric succession, Poland) are presented. Magneto- and biostratigraphy, magnetic susceptibility (MS), inorganic geochemistry, gamma ray spectrometry (GRS) and stable isotopes were studied. Indications of terrigenous input and redox proxies are discussed and compared with other Western Tethyan sections, especially those from the Balkan area (Grabowski et al., 2016) and Vocontian Basin (Morales et al., 2013; Emmanuel & Renard, 1993). The implications of results are referred to palaeogeographic and palaeotectonic reconstructions (e.g. Haas & Péró, 2004; Schmid et al., 2008; Plašienka, 2018).

Integration of magneto- and biostratigraphic data (Grabowski & Pszczółkowski, 2006) allows to correlate precisely even very distant sections from different tectonic units. Additionally, rock magnetism and geochemical data, gamma spectroscopy and carbon isotope analysis give a useful information about the environmental conditions in a basin during sedimentation time. During the Berriasian, Fatric basin was situated at the  southern shelf of the Penninic-Vahic (Alpine Tethys) ocean.  The Rówienka section covers stratigraphic interval from the upper part of M16r polarity chron up to the M14r chron (Berriasian/Valanginian boundary). MS shows increasing trend in M16n magnetozone and then a slight decrease in magnetozones M15r and M15n. GRS data and content of lithogenic elements (K, Al, Th, and others) show a long term increasing contribution of terrigenous material throughout the Upper Berriasian, which is in concordance with MS data. It is interpreted as an evidence of approaching collision at the southern margin of the Central Western Carpathians (CWC) (e.g. Schmid et al., 2008; Plašienka, 2018).  The same orogenic events controlled terrigenous supply in the Late Berriasian of Western Balkan section (Barlya, Grabowski et al., 2016) situated at the southern margin of Moesian platform. Tectonically induced continental runoff was most probably intensified by humid climate.

Carbon isotope data (δ13C) from Rówienka (Fig. 1) correlate very well with those from Barlya (Grabowski et al., 2016) and the Vocontian sections (Emmanuel & Renard, 1993). δ13C decreases towards the minimal values in the upper part of magnetozone M16n and then increases in magnetozones M15r and M15n in the uppermost Berriasian. Similar pattern may be seen in other magnetostratigraphically  dated Upper Berriasian sections from the Alpine – Carpathian  area as well as those without magnetostratigraphic calibration (Morales et al., 2013). This led to a conclusion, that δ13C variations might  be a good proxy for regional scale correlations; it’s palaeoenvironmental implications are discussed.

Trace elements, such as Ba and Ni are interpreted as a palaeoproductivity proxies (Tribovillard et al., 2006); an evidence of temporal increase of the basin productivity was found in Rówienka, in the upper part of M16r magnetic zone (lower part of the Upper Berriasian). Furthermore, total organic carbon (TOC) content in Rówienka is increasing along with the terrigenous input, which is likely an evidence of land provenance of organic matter.

Investigations were financially supported by the National Science Center, Poland (project no.: 2016/21/B/ST/10/02941) and Ministry of Science and Education, Poland (project no.: 683/N-POLONIUM/2010/0).