Mode of opening of an oceanic pull-apart; the 20°N basin along the Owen fracture zone (NW Indian Ocean)

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doi: 10.1002/tect.20083
Author(s): Rodriguez, Mathieu; Chamot-Rooke, Nicolas; Fournier, Marc; Huchon, Philippe; Delescluse, Matthias
Author Affiliation(s): Primary:
Ecole Normale Supérieure, Laboratoire de Géologie, Paris, France
Université Pierre et Marie Curie, France
Volume Title: Tectonics
Source: Tectonics, 32(5), p.1343-1357. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0278-7407 CODEN: TCTNDM
Note: In English. 101 refs.; illus., incl. 1 table, sketch map
Summary: Pull-apart basins are common features observed at releasing bends along major strike-slip faults. The formation and structural evolution of such basins have mostly been investigated in the continental domain and by sandbox laboratory experiments or numerical models. Here we present recently acquired multibeam bathymetry, 3.5 kHz echo sounder, and seismic profiles across the 20°N pull-apart Basin along the India-Arabia transform boundary, known as the Owen Fracture Zone (OFZ). Using nearby oceanic drilling (Deep Sea Drilling Project 222), we constrain the structural evolution of the basin since opening some 3 Myr ago. The 20°N Basin is large (90 km long and 35 km wide) despite limited transcurrent motion (∼10 km). The first stage involved the formation of a step over along the OFZ and the subsequent isolation of a subsiding half graben. Extension and subsidence were further partitioned over three distinct subbasins separated by complex sets of transverse faults. The size of the basin was enhanced by gravity-driven collapse. The 20°N Basin has been a catchment for Indus turbidites since its opening, which provide a good record of syn-sedimentary deformation. The deformation related to the subsidence of the half graben mimics rollover structures commonly encountered in salt tectonics, suggesting that subsidence was accommodated by one or several decollement layers at depth. Despite a different rheological context, the subsurface structure of the nascent oceanic 20°N Basin is very similar to the more mature continental Dead Sea Basin along the Levant Fault, which also displays subbasins separated by transverse faults. Abstract Copyright (2013), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2013
Research Program: DSDP Deep Sea Drilling Project
Key Words: 16 Structural Geology; 20 Geophysics, Applied; Arabian Sea; Basin analysis; Basins; Bathymetry; Cenozoic; Clastic sediments; DSDP Site 222; Deep Sea Drilling Project; Deformation; Experimental studies; Faults; Fracture zones; Geophysical surveys; Indian Ocean; Indus Fan; Laboratory studies; Leg 23; Marine methods; Multibeam methods; Neogene; Northwestern Indian Ocean; Numerical models; Ocean basins; Owen fracture zone; Pliocene; Pull-apart basins; Rheology; Sediments; Strike-slip faults; Subsidence; Surveys; Synsedimentary processes; Systems; Tertiary; Transform faults; Turbidite; Upper Pliocene; West Indian Ocean
Coordinates: N200529 N200530 E0613034 E0613033
Record ID: 2014007829
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom