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Category: Project

Description: Overview to the regional thrust wedge tectonics in Indonesia attempts to compile and review geologic settings related to the development of compressive structures. Comprehensive overview will be represented in six orogenic belts of various geologic settings: Langsa Fold-Thrust Belt (North Sumatra Basin), Banyumas Fold-Thrust Belt (Western Central Java), Kutei Basin, West Sulawesi Fold-Thrust Belt (Lariang-Karama Basins and Makassar Strait), Offshore Northern Banggai-Sula, and Berau-Bintuni Basins (extending from Onin Mountains, Misool Islands, and Obi Islands). Thrust wedge systems in this context relate to orogenic belts development and basement-involved in its nature. Key ideas and discussions encompass surface structural geology, geomorphology, and subsurface geology. Aiming to draw the big pictures, the integrated approaches will elaborate incorporate the roles of significant adjoining structural provinces to thrust wedge developments. Geomorphology will be the basis to construct regional structural maps, while seismic images and regional cross-sections will contribute to subsurface reconstructions. Synthesis will highlight similarities on geomorphic features, associated structures to thrust wedge system, Pliocene – Recent as critical time to orogenic building in Indonesia, geodynamic significance of strike-slip faulting, and geodynamic settings related to thrust wedge system in Indonesia. Thrust wedge orogenic belts share curvilinear thrust faults traces and intensive folding near mountain front. On the other hand, associated structures to thrust wedge include synclinal feature in thrust front, detachment folds, and transpressive-transtensional fault reactivation. Addressing geodynamic significance of strike-slip faulting, two groups can be defined: dependent and independent. Dependent strike-slip faults operate during thrust wedging and acts as tear faults or reactivated graben faults. Meanwhile, independent strike-slip faults run a role as a distinct geodynamic entity and coincide as adjoining structural provinces to thrust wedge system, as exemplified by Sumatran Fault in North Sumatra, Palu-Koro Transcurrent System in West Sulawesi, and Balantak Fault in East Sulawesi. As a conclusion, thrust wedge orogenic belts can develop in varying geologic settings in Indonesia, especially related to subduction and collisional tectonics.