Seismic images of a collision zone offshore NW Sabah/Borneo

• Published in: Marine and petroleum geology Vol. 25; no. 7; pp. 606 - 624
• Main Authors: Franke, Dieter, Barckhausen, Udo, Heyde, Ingo, Tingay, Mark, Ramli, Nordin
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2008; Elsevier Science
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Hydrocarbons; Marine; Marine geology; Northwest Borneo margin; Sedimentary rocks; Sedimentary succession; Seismic data; Tectonics. Structural geology. Plate tectonics; South China Sea; Borneo; Pacific Ocean; West Pacific; Sabah Malaysia; ISEW, South China Sea; ISEW, Borneo, Sabah; ISEW, Borneo; ISEW, South China Sea, Borneo Trough; Northwest Borneo margin; Sedimentary succession; Seismic data; Neogene; Paleogene; wave refraction; upper Tertiary; Malay Archipelago; seismic profiles; overthrust; faults; carbonate platforms; seismic reflection; deformation; thrust sheets; Cenozoic; continental margin; oceanic crust; models; Tertiary; crustal shortening; carbonates; plate tectonics; offshore; seismic methods; sedimentary structures; lower Tertiary; multichannel methods; gravity methods; Miocene; Phanerozoic; petroleum exploration; plate convergence
• ISSN: 0264-8172; 1873-4073
• DOI: 10.1016/j.marpetgeo.2007.11.004

Multichannel reflection seismic data from the southern South China Sea, refraction and gravity modelling were used to investigate the compressional sedimentary structures of the collision-prone continental margin off NW Borneo. An elongated imbricate deepwater fan, the toe Thrust Zone bounds the Northwest Borneo Trough to the southeast. The faults separating the individual imbricates cut through post-Early Miocene sediments and curve down to a carbonate platform at the top of the subsiding continental Dangerous Grounds platform that forms the major detachment surface. The age of deformation migrates outward toward the front of the wedge. We propose crustal shortening mechanisms as the main reason for the formation of the imbricate fan. At the location of the in the past defined Lower Tertiary Thrust Sheet tectonostratigraphic province a high velocity body was found but with a much smaller extend than the previously defined structure. The high velocity structure may be interpreted either as carbonates that limit the transfer of seismic energy into the sedimentary layers beneath or as Paleogene Crocker sediments dissected by remnants of a proto-South China Sea oceanic crust that were overthrust onto a southward migrating attenuated continental block of the Dangerous Grounds during plate convergence.