STRUCTURAL PATTERN AND STRATIGRAPHY ON BENGKULU FOREARC BASIN AREA

• Main Author: YULIAN, FERRY
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/18485
• Institution: Institut Teknologi Bandung

Bengkulu Forearc Basin was created by subduction of Indo-Australia and Eurasia Plate on western Sumatra. Study area is located on inner forearc that bounded by accretionary prism on the west. Oblique subduction has influenced the geological structures on this basin since Paleogene. The sediment can be divided into Paleogene and Neogene Units. Paleogene unit was deposited in Eocene-Late Oligocene graben and half graben. Neogene Unit was deposited Rafter erosional stage during Late Oligocene. It was started by Early-Early Middle Miocene transgression phase with deposition of limestones on the shelf and clastic sediments on the slope and deeper part. It was followed by regression phase with dominance of clastic unit that show prograditional in some part. Limestones unit also present on Late Miocene. Four structural trends are recognized in Bengkulu Basin on Paleogene. N-S and NE-SW trend that associated with NW-SE trend are formed graben and half graben that caused by motion of Mentawai and Sumatra Fault System. E-W trend is interpreted as rotated NE-SW fault. On the outer-arc, NW-SE trend developed by influenced of Sumatra subduction. Neogene structures developed on the western side of study area by outer-arc uplift and Mentawai Fault activity.