Forearc basin formation in the tectonic wake of a collision-driven, coastwise migrating crustal block: The example of the North Andean block and the extensional Gulf of Guayaquil-Tumbes Basin (Ecuador-Peru border area)

Abstract

Research Article| January 01, 2010 Forearc basin formation in the tectonic wake of a collision-driven, coastwise migrating crustal block: The example of the North Andean block and the extensional Gulf of Guayaquil-Tumbes Basin (Ecuador-Peru border area) César Witt; César Witt * 1Observatoire Océanologique de Villefranchesur-Mer, UMR Geosciences Azur (UPMC-IRD-CNRS), BP48, 06235 Villefranche/Mer, France2Departamento de Geología, Escuela Politécnica Nacional, Andalucia n/s, C.P. 17-01-2755 Quito, Ecuador *Present address: Fault Dynamics Research Group, Royal Holloway University, Egham TW20 0EX, London. E-mail: c.witt@es.rhul.ac.uk Search for other works by this author on: GSW Google Scholar Jacques Bourgois Jacques Bourgois 3Institute des Sciences de la Terre Paris, UMR 7193 UPMC-CNRS Case Courrier 124 4 Place Jussieu, 75252 Paris Cedex 05, France Search for other works by this author on: GSW Google Scholar Author and Article Information César Witt * 1Observatoire Océanologique de Villefranchesur-Mer, UMR Geosciences Azur (UPMC-IRD-CNRS), BP48, 06235 Villefranche/Mer, France2Departamento de Geología, Escuela Politécnica Nacional, Andalucia n/s, C.P. 17-01-2755 Quito, Ecuador Jacques Bourgois 3Institute des Sciences de la Terre Paris, UMR 7193 UPMC-CNRS Case Courrier 124 4 Place Jussieu, 75252 Paris Cedex 05, France *Present address: Fault Dynamics Research Group, Royal Holloway University, Egham TW20 0EX, London. E-mail: c.witt@es.rhul.ac.uk Publisher: Geological Society of America Received: 10 Dec 2007 Revision Received: 05 Dec 2008 Accepted: 08 Dec 2008 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2010 Geological Society of America GSA Bulletin (2010) 122 (1-2): 89–108. https://doi.org/10.1130/B26386.1 Article history Received: 10 Dec 2007 Revision Received: 05 Dec 2008 Accepted: 08 Dec 2008 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation César Witt, Jacques Bourgois; Forearc basin formation in the tectonic wake of a collision-driven, coastwise migrating crustal block: The example of the North Andean block and the extensional Gulf of Guayaquil-Tumbes Basin (Ecuador-Peru border area). GSA Bulletin 2010;; 122 (1-2): 89–108. doi: https://doi.org/10.1130/B26386.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Trench-parallel extensional strain resulting from the northward drift of the North Andean block has controlled the tectonic evolution of the Gulf of Guayaquil-Tumbes Basin, at least for the past ∼1.8–1.6 Ma. Industrial multichannel seismic and well data document that E-W to ENE, low-angle detachment normal faults, the Posorja and Jambelí detachment systems to the north and the Tumbes detachment system to the south, accommodated the main subsidence step along the shelf area during late Pliocene-Quaternary times (1.8–1.6 Ma to present). Two tectonic regimes showing different styles and ages controlled the evolution of the southern Ecuador and northern Peru continental margin and shelf. The ∼N-S extensional regime along the shelf area is related to North Andean block drift, whereas the E-W extensional regime along the continental margin results from tectonic erosion at depth. Strain rotation takes place along a major N-S–trending transfer system formed by the Inner Domito fault and the Inner Banco Peru fault, which bound the detachment systems to the west. The strike-slip component along this transfer system, roughly located at the continental margin-shelf break, evolved as a response to slip along the detachment systems bounding the basin to the north and to the south. The Tumbes detachment system is the master fault controlling basin evolution through time, and it may represent the shallower expression of a reactivated obduction megathrust. It connects landward with the continental structures assumed to be part of the eastern frontier of the North Andean block. For the past ∼2 Ma, the total lengthening calculated along a complete N-S transect of the Gulf of Guayaquil-Tumbes Basin ranges between 13.5 and 20 km. This lengthening is compatible with the documented drift of the North Andean block for the same period of time. The Gulf of Guayaquil-Tumbes Basin is not a classical pull-apart basin; it exemplifies a particular type of pull-apart basin basically controlled by (1) detachments extending downward across the brittle crust, and (2) plate coupling along the subduction décollement, which controls the inward segmentation of deformation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.