Badan Geologi

Pusat Survei Geologi

Initial Studies of the Marine Geophysical Survey in the Offshore Waigeo, West Papua



Abstract

The offshore northern Waigeo situated and evolved within the obliquely converging of the Australian and Pacific plates boundary zone and bound by an active left-lateral transform fault of the Sorong Fault Zone (SFZ) in the southern part. In general the Waigeo offshore characterized by +200 nT to-150 nT of total magnetic intensities which indicate that the study area possibly overlain by a homogenous rock of oceanic origin in the form of highs (terranes) and lows (basins). Seismic data indicate that the morphology of the study area relatively steep due to the tectonic contact boundary between islandĀ­terranes of Waigeo and between Ayu islands and Pacific Oceanic crust. This tectonic contact boundaries characterized by the present of Waigeo Trough that extends southeast-northwest direction. Seismic data reveals about 1000 meters thick of acoustically chaotic to laminated, indicate fine-grained sediments of slumps at Waigeo Trough slope and trough floor, and about 1500 meters thick of pelagic sediments at the Ayu Trough.

Abstrak

Lepas pantai Waigeo bagian utara beradadan berkembang pada zona konvergensi oblig antara lempeng Australia dan lempeng Pasifik dan dibatasi oleh sesar geser aktif mengiri Sarong (Zona Sesar Sarong) di bagian selatan. Secara umum perairan Waigeo dicirikan oleh intensitas magnet total antara + 200 nT hingga -15 0 nT yang mengindikasikan bahwa daerah studi dialasi oleh batuan homogen asal samudera membentuk tinggian (teran) dan lembah (cekungan). Data seismik menunjukkan bahwa morfologi daerah studi relatif curam karena batas kontak tektonik antara pulau-teran Waigeo dan antara kepulauan Ayudan kerak samudera Pasifik. Batas kontak tektonik ini dicirikan dengan adanya Parit Waigeo yang memanjang berarah tenggara-baratlaut. Data seismik menunjukkan sedimen yang secara akustik kaotik hingga berlapis dengan ketebalan sekitar 1000 meter, mencirikan sedimen slump berbutir halus pada lereng dan lantai Parit Waigeo, dan sekitar 1500 meter ketebalan sedimen pelagik di ParitAyu.

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Jurnal Geologi dan Sumber Daya Mineral

Vol. 17 No. 3, Agustus 2016

0853 - 9634

JGSM