Hans-Gert Linzer¹

(1) Rohoel-Aufsuchungs AG, Vienna, Austria

ABSTRACT: Cyclic Channel Systems in the Molasse Foreland Basin of the Eastern Alps - the Effects of Late Oligocene Foreland Thrusting and Early Miocene Lateral Escape

Visualisation of 3D seismic data of the Molasse foreland basin illuminates vertically stacked axial channel systems and Alpine foreland imbricates. The subsurface foreland thrust belt of the Eastern Alps consists of Late Oligocene imbricates superimposed by Early to Middle Miocene lateral escape structures. The channel systems are situated close to the frontal wedge of the Alpine foreland thrust and occur in the Late Oligocene to Early Miocene deep water sequences. The geometry of the channels is influenced by lateral mass flow events from both the northern and southern flanks of the molasse basin. The early events were caused by gradually steepening of the northern flank of the basin due to flexural loading by postcollisional crustal shortening during Oligocene times. The late mass flow events were associated with gradually steepening of the southern basin floor caused by southwards roof thrusting onto the frontal wedge of the foreland thrust belt. The complex triangle zone with passive roof backthrusts of Early Miocene foreland Molasse sediments formed in front of lateral escaping wedges of the Eastern Alps. The gently folded channel systems form major gas reservoirs in the eastern Molasse basin.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado