The Global boundary Stratotype Section and Point (GSSP) of the Carnian Stage (Late Triassic) at Prati di Stuores/Stuores Wiesen Section (Southern Alps, NE Italy)

Abstract

The Global boundary Stratotype Section and Point (GSSP) for the base of the Carnian Stage (Late Triassic) is defined on the north flank of the Cordevole Valley, on the southern slopes of the crest separating the Badia/Abtei and the Cordevole valleys (46° 31' 37"N, 11° 55' 49"E) at an elevation of 1980 m, approximately 4.7 km south of San Cassiano/St. Kassian in the Dolomites (Southern Alps). The Prati di Stuores/Stuores Wiesen section (Province of Belluno, Veneto Region, Italy) is located a few hundred meters east of Pralongia, a locality northeast of Arabba (Belluno). The section consists of hemipelagites and thin turbidite beds (both siliciclastic and carbonate intraclastic), deposited below storm wave-base with a high but variable sediment accumulation rate (San Cassiano Fm.). The GSSP boundary is located at the base of bed SW4, 45 m above the base of the San Cassiano Fm. Bed SW4 yielded ammonoids including Daxatina canadensis (Whiteaves), which is the primary global marker for identifying the base of the Carnian Stage. The secondary marker for the Carnian Stage, the conodont Paragondolella polygnathiformis (Budurov and Stefanov), appears 70 cm above the first occurrence of Daxatina canadensis and at the base of a long normal-polarity magnetic zone (S2n) in close proximity to the boundary. Furthermore, the GSSP is located one ammonite subzone just above a level dated at 237.77 ± 0.14 Ma.