TECTONOSTRATIGRAPHY AND STRUCTURAL ELEMENT STUDY OF OFF-SHORE NORTH LHOKSEUMAWE, NORTH SUMATRA BASIN

• Main Author: ARIF NURFARHAN (NIM: 22013006), AFFAN
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/25071
• Institution: Institut Teknologi Bandung

<p align ="justify">North Sumatra Basin is a modern back-arc basin formed by subduction between the Indo-Australian Plate and Eurasia. Gravity anomaly map and seafloor topography map suggest tha the thickest sediment accumulation located off-shore north of Lhokseumawe. Regional strike slip presumed to trigger the formation of depression in this area. Three general tectonostratigraphical units mapped using the 2D seismic data and well-log, are; pre-rift unit, which become the base of North Sumatra Basin, since Eocene. The syn-rift unit (Bampo, Parapat, Belumai, and Baong), concentrated near the large fault give the indication of extensional phase in the basin, which have Early Oligocene – Late Miocene age. The post-rift unit (Baong Formation, Belumai, Intra-Keutapang, Keutapang, Seureula, dan Julu Rayeuk fm.), distributed equally troughout the study area since Late Miocene – Late Pliocene, indicating the thermal subsidence stage of the basin. The structural pattern predominant at N-S trending, presumed inherited from the transtensional tectonic of Sumatran Fault which took place since Eocene, providing pull-apart basin of the study area (Darman and Sidi, 2000). There is one fold-thrust belt which doesn’t involve the basement, in the southern part of the area, as the expression of the Plio-Pleistocene compressive tectonic presence (Barber et al, 2005). According to the palinspatic restoration, and strain analyses, the study area are known to have the 1% shortening deformation along NE-SW direction<p align ="justify">