Structural evolution and strike-slip tectonics off north-western Sumatra

Type Article
Date 2010
Language English
Author(s) Berglar Kai1, Gaedicke Christoph1, Franke Dieter1, Ladage Stefan1, Klingelhoefer FraukeORCID2, Djajadihardja Yusuf S.3
Affiliation(s) 1 : Fed Inst Geosci & Nat Resources, Bundesanstalt Geowissensch & Rohstoffe, D-30655 Hannover, Germany.
2 : IFREMER, Ctr Brest, F-29280 Plouzane, France.
3 : Agcy Assessment & Applicat Technol, Jakarta 10340, Indonesia.
Source Tectonophysics (0040-1951) (Elsevier Science Bv), 2010 , Vol. 480 , N. 1-4 , P. 119-132
DOI 10.1016/j.tecto.2009.10.003
WOS© Times Cited 22
Keyword(s) Oblique subduction, Strike slip, Forearc basin, Sumatra, Mentawai Fault Zone, West Andaman Fault
Abstract Based on new multi-channel seismic data, swath bathymetry, and sediment echosounder data we present a model for the interaction between strike-slip faulting and forearc basin evolution off north-western Sumatra between 2 degrees N and 7 degrees N. We examined seismic sequences and sea floor morphology of the Simeulue- and Aceh forearc basins and the adjacent outer arc high. We found that strike-slip faulting has controlled the forearc basin evolution since the Late Miocene. The Mentawai Fault Zone extends up to the north of Simeulue Island and was most probably connected farther northwards to the Sumatran Fault Zone until the end of the Miocene. Since then, this northern branch jumped westwards, initiating the West Andaman Fault in the Aceh area. The connection to the Mentawai Fault Zone is a left-hand step-over. in this transpressional setting the Tuba Ridge developed. We found a right-lateral strike-slip fault running from the conjunction of the West Andaman Fault and the Tuba Ridge in SSW-direction crossing the outer arc high. As a result, extrusion formed a marginal basin north of Simeulue Island which is tilted eastwards by uplift along a thrust fault in the west. The shift of strike-slip movement in the Aceh segment is accompanied by a relocation of the depocenter of the Aceh Basin to the northwest, forming one major Neogene unconformity. The Simeulue Basin bears two major Neogene unconformities, documenting that differences in subsidence evolution along the northern Sumatran margin are linked to both forearc-evolution related to subduction processes and to deformation along major strike-slip faults. (c) 2009 Elsevier B.V. All rights reserved.
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