Facies and Stratigraphic Analysis of the Permian Succession in the Denison Trough, SW Bowen Basin, Queensland, Australia

Abstract

This paper investigates the distribution of depositional systems in time and space of the Permian succession of the Denison Trough and surrounding areas, southwest Bowen Basin, Queensland. A unified facies scheme is presented for the shallow marine to coastal plain succession. Seven facies associations are defined using a combination of sedimentological and ichnological criteria, and represent shelfal, offshore, shoreface, delta front to river mouth, delta plain channel, delta plain lagoon and bay, and upper delta plain lake and mire environments of deposition. The thickness distribution patterns of component formations is addressed by means of a series of isochore maps, based on examination of over 300 subsurface intersections. The Reids Dome Beds and Cattle Creek Formation were formed during the Early Permian extensional phase of basin history and are confined to extensional depocenters in the Denison Trough region. The Cattle Creek Formation marks the initial marine inundation of the Denison Trough, and a series of deltas prograded into the basin from the western margin. The Aldebaran Sandstone, Freitag and Ingelara Formations, and Catherine Sandstone were formed during a Middle Permian period of thermal relaxation, and show a more even sediment distribution, overtopping the earlier topographic barrier of the Comet Ridge to be continuous into the Taroom Trough axis of the basin. During this time, a series of deltas issued eastward from the western basin margin, stacking in a compensational manner. The Peawaddy Formation, Black Alley Shale and Bandanna Formation were formed during a Middle to Late Permian phase of foreland thrust loading that continued into the Early Triassic. During this time, construction of a continental volcanic arc along the eastern margin of the basin restricted the wave fetch of the basin and formed a topographic barrier, focusing sediment dispersal into large, southward (axially)-draining systems. Sediment thickness during the foreland loading phase increased eastward from the Denison Trough into the foredeep axis of the Taroom Trough. Changes in deltaic style coincide with the changes in the geotectonic context of the basin, from initially fluvially-influenced (extensional phase), through wave-influenced to wave-dominated (thermal relaxation) to fluvially-dominated (foreland loading).

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016