ASGP (2015), vol. 85: 675–684

Nd AND Sr ISOTOPIC EVIDENCE FOR PROVENANCE OF CLASTIC MATERIAL OF THE UPPER TRIASSIC ROCKS OF SILESIA, POLAND

Natalia KONIECZNA (1), Zdzisław BELKA (2) & Jolanta DOPIERALSKA (3)

1) Institute of Paleobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warszawa, Poland; e-mail: nkonieczna at twarda.pan.pl
2) Isotope Laboratory, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań, Poland; e-mail: zbelka at amu.edu.pl
3) Poznan Science and Technology Park, Adam Mickiewicz University Foundation, Rubież 46, 61-612 Poznań, Poland; e-mail: dopieralska at amu.edu.pl

Konieczna, N., Belka, Z. & Dopieralska, J., 2015 (first published on-line in 2014). Nd and Sr isotopic evidence for provenance of clastic material of the Upper Triassic rocks of Silesia, Poland. Annales Societatis Geologorum Poloniae, 85: 675–684.

Abstract: Nd and Sr isotope data were used to characterize the sources of the Upper Triassic (Keuper) siliciclastic rocks of Silesia in southern Poland. This continental succession, consisting predominantly of fine-grained mud- stones and siltstones, yields a remarkably uniform Nd isotopic composition. Nd model ages T2DM vary from 1.56 to 1.69 Ga and εNd values are in the range from –8.9 to –11.2, documenting old crust contribution in the provenance. In contrast, the Sr isotopic composition (87Sr/86Sr) of the clastics exhibits a relatively large variation from 0.710 to 0.723. The isotopic compositions indicate that the southern part of the Germanic Basin in Silesia was supplied with clastic material from the Bohemian Massif. The axis of the drainage area must have crossed from SW to NE the Saxothuringian units of the East Sudetes and most probably also the area of the Tepla–Barrandian Unit. There is no indication of any sediment transport from the Moravo-Silesian Belt and the Fore-Sudetic Block. It seems, that the Palaeozoic rocks of the latter domain must have been buried completely during Late Triassic times.

Manuscript received 16 January 2014, accepted 4 August 2014

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