ALBERT

Description: 〈p〉Different tectonic characteristics are exhibited among Maluku Sea and Banggai-Sula Microcontinent which are located side by side to each other. However, the northern part of the Banggai-Sula Microcontinent, positioned along the Maluku Sea margin, has a complex geological structure to be observed. Therefore, this study aimed to analyze the subsurface structure and sediment thickness due to extensional mechanisms in the area, using the gravity method. The investigation was executed through power spectrum analysis and three-dimensional (3D) modeling of complete Bouguer anomaly data. Eleven x-direction profiles were employed to determine the depth of the contact boundaries between the shallow and the deep discontinuities. The results showed that the deep and shallow discontinuities obtained from the 3D modeling and spectrum analysis have similar values, with depths ranging between 14.52 km and 15.14 km, as well as 1.23 km and 1.39 km, respectively. The shallow discontinuity area was dominated by sediment rocks with a 2.6 g/cm〈sup〉3〈/sup〉 to 2.8 g/cm〈sup〉3〈/sup〉 density. The area is interpreted as the Buya Formation superimposed by the Tanamu Formation. The deep discontinuity area with a depth of up to 16 km. We found areas of high density (density value is 〉3 g/cm〈sup〉3〈/sup〉) adjacent to low rock density (density value is 2 g/cm〈sup〉3〈/sup〉 to 2.3 g/cm〈sup〉3〈/sup〉). The observed are interpreted as fault-bounded formations of terrestrial conglomerates and sandstones from the Bobong Formation. These formations are located within a half-graben and are found to rest unconformably on the basement towards the southern onshore region.〈/p〉