Abstract: The Stratigraphic Framework of the Triassic in Western Europe

Vittorio De Zanche, Gianolla Piero, Mietto Paolo

During the Triassic, the main paleogeographic domains in Western Europe were: Arctic, Germanic and Tethyan, each of them characterized by different facies and sedimentary evolution. In spite of the existence of different paleobiogeographic provinces and distinct biochrono-stratigraphic scales, good correlations can be drawn.

On the whole, the Triassic forms a major first-order transgression-regression cycle whose limits correspond to the Permian-Triassic and Norian-Rhaetian boundaries. Its peak transgression is placed within the Fassanian (Chiesense Sbz.). The major first-order cycle includes five second-order transgressive-regressive cycles, as seems to be demonstrated in the Barents Sea and in the Southern Alps. In the Southern Alps the peak transgressions, which correspond to third-order maximum flooding surfaces, occur: (1) in the early Spathian (Tirolites cassianus Z.); (2) in the Pelsonian (Balatonicus Sbz.); (3) in the Fassanian (Chiesense Sbz.); (4) in the Julian (Aon Sbz.). Due to the lack of ammonite data, the peak transgression of the fifth second-order cycle lies inside the Norian. The maximum regressions, which bound the second-order

cycles and coincide with third-order top lowstands, occur: (1) at the Permian/Triassic boundary; (2) in the Bithynian (Osmani Sbz.); (3) in the Illyrian (Abichi Sbz.); (4) in the Longobardian (Regoledanus Sbz.); (5) in the Tuvalian (? Subbullatus Z.); (6) near the Norian-Rhaetian boundary. The Balatonicus, Chiesense and Aon peak transgressions allow good correlations with the Germanic Basin. Moreover a good correspondence exists between the third-order sequences in the Triassic basins in the Western Europe.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994