(GSSP) of the Ladinian Stage (Middle Triassic) at Bagolino (Southern Alps, Northern Italy) and Its Implications for the Triassic Time Scale
Articles 233 by Peter Brack1, Hans Rieber2, Alda Nicora3, and Roland Mundil4 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 1 Departement Erdwissenschaften, ETH-Zentrum, CH-8092 Zürich, Switzerland. 2 Paläontologisches Institut, Universität Zürich, CH-8006 Zürich, Switzerland. 3 Dipartimento di Scienze della Terra, Università di Milano, Via Mangiagalli 34, I-20133 Milano, Italy. 4 Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709, USA. The Global boundary Stratotype Section and Point (GSSP) for the base of the Ladinian Stage (Middle Tri- Historical context of the Ladinian Stage assic) is defined in the Caffaro river bed (45°49’09.5’’N, The first formal recognition of a stratigraphic interval comprising what 10°28’15.5’’E), south of the village of Bagolino is now called Ladinian orginates from the subdivisions of the Triassic (Province of Brescia, northern Italy), at the base of a System proposed by E.v. Mojsisovics. Ammonoids served as the main biostratigraphic tool for these divisions. By 1874 and with later modi- 15–20-cm-thick limestone bed overlying a distinct fications (e.g., 1882), Mojsisovics used the name “Norian” for a strati- groove (“Chiesense groove”) of limestone nodules in a graphic interval including, at its base, the South Alpine Buchenstein Beds and siliceous limestones of Bakony (Hungary). Because Moj- shaly matrix, located about 5 m above the base of the sisovics erroneously equated this interval with parts of the ammonoid- Buchenstein Formation. The lower surface of the thick rich Hallstatt-limestones, he used the term “Norian” as the stage name, limestone bed has the lowest occurrence of the which refers to the Norian Alps around Hallstatt near Salzburg (Aus- tria).
[Show full text]