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Episodes 2005; 28(4): 233-244

Published online December 1, 2005


Copyright © International Union of Geological Sciences.

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

Peter Brack1, Hans Rieber2, Alda Nicora3, Roland Mundil4

1Departement Erdwissenschaften, ETH-Zentrum, CH-8092 Zürich, Switzerland.
2Paläontologisches Institut, Universität Zürich, CH-8006 Zürich, Switzerland.
3Dipartimento di Scienze della Terra, Università di Milano, Via Mangiagalli 34, I-20133 Milano, Italy.
4Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


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.