Tectonic Characteristics and Evolution Banda Sea Region

Abstract

Middle Miocene onwards, the Banda Sea started to be devolved due to retreat and roll-back of the northwards subducting Indo-Australian oceanic plate below the south-easternmost Eurasian margin. This process is facilitated by a trench perpendicular tear in the slab. The tear dissects Sulawesi Island along the Palu-Matana Fault and delimits the southern boundaries of Banggai-Sula, Birds Head (BH) and the northern boundary of Banda Sea plate. Dominantly, this structure is sinistral in nature from Celebes Sea up to an offshore point located half way between Seram and Misool Islands, which we think is the tip of the tear. To the east of this point, the deformation is dominated by thrusting and accretion that produce the so called Seram Accretionary Wedge (SAW). SAW extends and includes part of onshore Seram Island and extends into the Seram Trench and curves around the outer margin of Banda Arc including the Tanimbar, Jamdena and offshore Timor Leste. South of Obira Island is a quadruple junction where, four major structures namely Palu-Matana, Poh-Mangole, Seram, and Sorong fault zones meet. The Sorong Fault Zone (SFZ) separates the Birds Head (BH) and Halmahera and has accommodated more than 48 km sinistral off-set over the last few million years. In the NW margin of Cendrawasih Basin, Sorong and Yapen faults meet and the eastern boundary of BH is delimited by the Van Damen peninsula which comprises ultra high pressure metamorphic rocks with exhumation ages as young as 1 Ma. Earthquake focal mechanism solutions indicate that the eastern boundary of BH is linked with a large scale offshore normal fault related to the exhumation of the Van Damen peninsula that contribute to the development of Cendrawasih Basin (CB). The eastern margin of CB is a major transpressive belt along which BH and the main body of the bird (Papua & Irian Jaya) is decoupled. This implies that the Aru Basin which is located at the NE corner of Banda Arc is a FFT junction. In this contribution we will discuss the characteristics of the major structures around Banda Sea region and provide constraints on its evolution during the Neogene, based on satellite remotely sensing and recently acquired high resolution bathymetric images and 2D seismic profiles mainly from Celebes Sea, Makassar Strait, Gorontalo, Tomori, Bone, off-shore Seram-Aru, Kafiau-Misool corridor, Cendrawasih basins and Indonesian side (Jamdena and Roti) of the NW Australian Shelf.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015