The Spathian-Anisian (Lower-Middle Triassic) Boundary in the candidate GSSP section at Deşli Caira, Romania: Review of existing data, new findings, and comparison with other candidates

The Deşli Caira section in Romania has been renowned for its ammonoid record for more than a century, recording the transition from the Lower Triassic (Spathian) to the Middle Triassic (Anisian), and for the last ca 20 years it has been a candidate GSSP for the Spathian-Anisian Boundary. We gather the existing data on this section, add a high-resolution δ¹³C curve, and correlate and compare the dataset with the records of other competing GSSP candidates. We show that there are turnovers of conodont, ammonoid and foraminifera species in the Deşli Caira section within the boundary interval, accompanied by a maximum in the δ¹³C curve and a distinctive pattern in the palaeomagnetic data. We also show that currently there exist two different levels for the Spathian-Anisian Boundary in the literature. In comparison with Deşli Caira the other candidate sections for the Spathian-Anisian Boundary (Kcira section, Albania; Wantou section, China) have smaller datasets, in that both are lacking a detailed ammonoid stratigraphy. Thus, Deşli Caira is the better suited section for hosting the GSSP, once the problem with the two boundary levels is solved by detailed description of the ammonoid record.