STRATIGRAPHY MODEL OF EAST BIAK REGIONS BASED ON MAGNETOTELLURIC DATA

• Main Author: - NIM: 22016004 , Alviyanda
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25428
• Institution: Institut Teknologi Bandung

<p align="justify">Biak Island is one of the New Guinea islands which is thought to have originated from the Australian Continental Plate passive margin in Mesozoic (Hall, 2002; Hill and Hall, 2003). During Paleogene, this passive margin underwent tectonic collision activity with the Pacific Oceanic Plate to form the bedrock of Biak Island and its basin. The Biak Basin is one of the semi-mature basins in Eastern Indonesia with hydrocarbon potential (PND, 2006). The existence of East Biak in the northern part of this basin which is massively covered coral limestone and chalk become obstacles in knowing the stratigraphy condition. The purpose of this research is to identify the subsurface geological conditions of East Biak area based on rock resistivity values distribution. <br /> <br /> <br /> <br /> Magnetotelluric (MT) method is a passive geophysical method that able to interpret subsurface geology based on variation of rock resistivity value up to depth 5 – 10 km. The MT measurements in East Biak consist of two line, namely west-east line and south-north line, with a total of 25 measurement points. Cross-sectional variations of rock resistivity values generated from MT can be used to identify rock distribution in East Biak subsurface and surrounding areas. <br /> <br /> <br /> <br /> Five lithological units have been interpreted based on variation of rock resistivity values. The resistivity values varied on the surface for each unit as unit as follows: 1 &#937;m – 6,530 &#937;m, 1 – 19.222 &#937;m, 1 – 6.021 &#937;m, 1 – 30 &#937;m, and 8 &#937;m – 5,235 &#937;m. The East Biak stratigraphy model is predominantly dominated by sedimentation of carbonates comprising two sequences deposition, namely Early Neogene sequence with thickness 1,000 m – 3,000 m and Late Neogene – Quarter sequence with thickness 180 m – 2,450 m. Unconformity were found between the deposition of these two sequences due to tectonics activity which separated Supiori and Biak Island. <p align="justify"> <br />