Abstract: The Jura Thrust Belt: Tectonic History and Prospectivity of a Leading Edge of the Western Alps

Yann Philippe, Gerard Jacquart, Alain Mascle

The Jura Thrust Belt developed in Pliocene times as the result of the late stage of advance to the northwest of the western Alps. The main decollement level is hosted in late and/or middle Triassic salt layers. The belt is superimposed on a Mesozoic platform partially eroded in early Tertiary times. In Oligocene times, the present Jura area was actually a regional high between the Molasse basin alpine foredeep to the east, and the Bresse rift basin to the west. At depth several isolated and elongated Stephanian-Permian troughs have been recognized from seismic and well data. They unconformably rest on a Paleozoic basement that was once part of the European segment of the Variscan Thrust Belt.

Several small gas field have been developed in the past and significant oil shows have more recently been tested. Source rocks are generally believed to be late Paleozoic coals and oil shales. Producing horizons are early Triassic continental sandstones with excellent petrophysical characteristics, and slightly less prospective middle Jurassic limestones and dolostones. Untested plays could also be present in the underlying early Permian sandstones.

Recent studies have focused on the geometry of the thrust belt through regional laterally coherent balanced sections, and oil-source rock correlations.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France