Fossil Record 12(2): 197-205, doi: 10.1002/mmng.200900007
Stratigraphic significance of carbon isotope variations in the shallow-marine Seis/Siusi Permian–Triassic boundary section (Southern Alps, Italy)
expand article infoS. H. Kraus, S. Siegert, W. Mette§, U. Struck|, C. Korte
‡ Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74–100, 12249 Berlin, Germany§ Institut für Geologie und Paläontologie, Universität Innsbruck, Innrain 52, 6020 Innsbruck, Austria| Museum für Naturkunde Berlin, Invalidenstraße 43, 10115 Berlin, Germany¶ Department of Geography and Geology & Nordic Center for Earth Evolution (NordCEE), University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark and Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74–100, 12249 Berlin, Germany
Open Access
Abstract
Carbonate carbon-isotope values from the Permian–Triassic (P–T) boundary section at Seis/Siusi (Southern Alps, Italy) show a trend similar to that in numerous other P–T boundary sections worldwide. Values decrease from 3.2‰ (V-PDB) in the upper Bellerophon Limestone Formation (Late Permian) to a minimum of –1.7‰ in the lower Mazzin Member. This minimum may represent the P–T boundary. The overall declining carbon-isotope trend is interrupted by a ca. 1‰ positive excursion in the higher Tesero Oolite Horizon. This positive peak is located at a higher lithostratigraphic level than a comparable peak in the adjacent Pufels section, which suggests that the Tesero Oolite Horizon in the Seis section is stratigraphically slightly older than in the Pufels section, and this is also suggested by palaeomagnetic correlation. It is therefore concluded that the base of the Tesero Oolite Horizon does not reflect a synchronous "current event" but is slightly diachronous, a result that was previously shown by biostratigraphic correlation. Nevertheless, this suggestion should be verified by further detailed litho-, magneto- and chemostratigraphic analysis of other P–T sections in the Southern Alps.

doi:10.1002/mmng.200900007