Tectonic Evolution of Thin and Thick-skinned Fold and Thrust Belts; Applications to the Papua New Guinea Fold and Thrust Belt
Most fold and thrust belts formed in subduction and collision terranes are characterized by both supra-basement thin-skinned thrust architectures as well as by basement-involved thick-skinned thrust systems. Thin-skinned thrust systems commonly form critically tapered Coulomb wedges where the basal detachment friction and the internal friction within the wedge control the fundamental geometries. Such wedges are dramatically affected by surface processes – syn-contractional erosion and or sedimentation. The reactivation of pre-existing basement fabrics and faults is common in many thrust belts forming thick-skinned structure where contraction on steep reverse faults produces plateau-style uplifts. These are usually characterized by inversion of steep basement faults, that produces asymmetric anticlines with steep to overturned forelimbs and gently dipping back limbs. Many of these terranes contain significant hydrocarbon accumulations including those of PNG, the Zagros fold belt, the sub Andean retro-arc basins and the Rocky Mountain uplifts of western USA. The structural styles of the Papua New Guinea thrust belt are reviewed and compared with these classic examples of thin-thick skinned thrust terranes in order to highlight their geometric similarities, thrust mechanics and hydrocarbon trapping styles.
AAPG Datapages/Search and Discovery Article #90371 © 2020 AAPG Asia Pacific Region, The 1st AAPG/EAGE PNG Geosciences Conference, PNG’s Oil and Gas Industry: Maturing Through Exploration and Production, Port Moresby, Papua New Guinea, February 25-27, 2020