The Global boundary Stratotype Section and Point (GSSP) for the base of the Ladinian Stage (Middle Triassic) is defined in the Caffaro river bed (45°49’09.5’’N, 10°28’15.5’’E), south of the village of Bagolino (Province of Brescia, northern Italy), at the base of a 15–20-cm-thick limestone bed overlying a distinct groove (“Chiesense groove”) of limestone nodules in a shaly matrix, located about 5 m above the base of the Buchenstein Formation. The lower surface of the thick limestone bed has the lowest occurrence of the ammonoid Eoprotrachyceras curionii (base of the E. curionii Zone; onset of the Trachyceratidae ammonoid family). Secondary global markers in the uppermost Anisian include the lowest occurrence of conodont Neogondolella praehungarica and a brief normal-polarity magnetic zone recognized in closely correlated sections including the principal auxiliary section at Seceda in the Dolomites. The GSSP-level is bracketed by U-Pb single zircon age data from volcaniclastic horizons, indicating a boundary age of ca 241 Ma.
|Titolo:||The Global Boundary Stratotype Section and Point (GSSP) of the LADINIAN STAGE (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and its implications for the Triassic time scale|
NICORA, ALDA (Penultimo)
|Settore Scientifico Disciplinare:||Settore GEO/01 - Paleontologia e Paleoecologia|
|Data di pubblicazione:||2005|
|Appare nelle tipologie:||01 - Articolo su periodico|