SOME CONSTRAINT IN TECTONIC RECONSTRUCTIONS OF BIRD'S HEAD REGION, PAPUA, INDONESIA

The Bird’s Head region of Papua, Indonesia is one of the most complex geology and tectonic history among other area in the Eastern Indonesia. Their geologic relationships are poorly understood due to complex tectonic history in both time and space. Tectonic evolution and basin development of region is known as one the most complex in the world. It involves convergent of three major plates: Indo-Australian, Pacific and Eurasia that has been occurring since early Tertiary. This tectonic event was generated several independent tectonic blocks in which their deformation involving rotation and translation in which some involving large displacements resulting from major oblique strike-slip faulting. As a results is very difficult to ramification their tectonic history using only rely on the field geological evidence due inconsistency data both stratigraphy and structural development. The main objective of this paper is to present results of ongoing geology investigation in particular concentrated in developing constraint in tectonic reconstructions of this region.

This study is based on large amount of newly acquired 2D seismic data from several locations surrounding Bird’s Head region such as North Salawati Basin, Sorong Fault Zone, Misool Island, Seram Island and Cendawasih Bay. This new interpretation indicating new information leads to generate a new propose tectonic reconstructions model in order to fit the new data. Several regional balancing cross-sections were generated for supporting the development 2D palinspatic reconstructions and strain comparison of several areas within the region.

The results of this study indicates that stratigraphy of the Bird’s Head region was varies from area to area which is difficult to correlates. This evidence is parallel by the fact that deformation was also inconsistent indicating by large variation in strain number. Palinspatic reconstructions suggested that deformation had been started as early as Late Mesozoic characterized by several unconformity surfaces. Structural pattern suggested that Bird’s Head regions experienced some rotation and also translation resulting from strike-slip faulting deformation. All of these evidences are new for the region for example as comparison with Bird’s Body or Northern Australian margin. Therefore, it’s demonstrated that a new tectonic reconstructions model should be generated based on the results of this recent study.