The sedimentological interpretation of seismic and borehole data derived from the Burdigalian Upper Marine Molasse Group of the central North Alpine foreland basin enables a detailed reconstruction of the shallow-marine architecture. The different seismic facies are assigned to the shoreface/foreshore, nearshore, and offshore depositional systems. Mapping of the seismic facies on the seismic line reveals the presence of two prograding sequences (Luzern and St. Gallen formations) that are separated by an unconformity.

The subsidence analysis suggests that the evolution of the Upper Marine Molasse was primarily controlled by the interaction between tectonic subsidence and sediment supply. The distal transgressions of the Luzern and St. Gallen formations and the establishment of shallow-marine environments were caused by enhanced subsidence rates in the distal reaches associated with increased sediment supply rates. The development of the sequence boundaries separating the Luzern and St. Gallen formations and the regression at the end of the St. Gallen Formation, however, were controlled by uplift in the distal part of the basin.

The subsidence and sediment flux analyses of the Upper Marine Molasse allow an improved understanding of the tectonic and denudation history of 
 
 

©Copyright 1997. The American Association of Petroleum Geologists. All rights reserved.
1Manuscript received March 28, 1996; revised manuscript received October 16, 1996; final acceptance February 24, 1997.
2Geologisches Institut, Universität Bern, Baltzerstrasse 1, CH-3012 Bern, Switzerland. Present address: Friedrich-Schiller Universität Jena, Institut für Geowissenschaften, 07749 Jena, Germany.
3Geoform AG, 8401 Winterthur, Switzerland. 
4Geologisches Institut, Universität Bern, Baltzerstrasse 1, CH-3012 Bern, Switzerland.
This project was supported by the Swiss National Science Foundation (grant no. 21-36219.91). We would like to thank B. Keller (Menggis and Lorenz, Luzern, Switzerland), A. Pfiffner, J. Màtyàs, G. Schreuers, O. Kempf, P. Strunck (University of Bern, Switzerland), and N. Ussami (University of São Paulo, Brazil) for fruitful discussions. The critical review of T. E. Jordan (Cornell University, Ithaca, New York) is kindly acknowledged. Thanks go to SEAG (Schweizerische Erdöl AG) for allowing us to publish lines 8307 and 7525, as well as the geophysical and mud-log data of the Hünenberg 1 and Boswil 1 wells.