Northern New Guinea Wrench Fault System: A Manifestation of Late Cenozoic Interactions Between Australian and Pacific Plates: ABSTRACT

Abstract

Cenozoic plate interactions between the Australian and Pacific plates have yielded a variety of convergent tectonic styles. Two major products of this convergence are the Sorong fault zone of Irian Jaya and the Ramu-Markham fault zone of Papua. The Sorong fault system has been documented to extend westward more than 500 mi (800 km) from Teluk Sarera to Kep Banggai as a left-lateral strike-slip fault. The Ramu-Markham fault system is of disputed displacement and has been previously interpreted to extend from over 310 mi (500 km) just east of the Sepik River into the Huon Gulf. A consideration of Australian-Pacific Cenozoic plate kinematics, Holocene vectors, earthquake focal mechanisms, photogeologic lineation analyses, and the assimilation of other pertinent geologic data suggests that the Ramu-Markham fault zone is an extension of the Sorong fault system and that together they represent significant left-lateral strike-slip motion in rigid crustal basement. This motion has produced large scale en echelon surface expressed faults and folds in detached overlying Neogene sediments. Furthermore, this wrench fault system has led to the transcompressional development and deformation of the Meervlakt, Piore, Sepik, and Ramu basins of northern New Guinea. An understanding of the tectonic evolution of these basins is tantamount to an assessment of their evolving hy rocarbon potential. End_of_Article - Last_Page 980------------