Active detachment faulting above the Peruvian flat slab

Research Article| June 01, 2002 Active detachment faulting above the Peruvian flat slab Brendan McNulty; Brendan McNulty 1Department of Earth Sciences, California State University Dominguez Hills, 1000 East Victoria Street, Carson, California 90747, USA Search for other works by this author on: GSW Google Scholar Daniel Farber Daniel Farber 2Lawrence Livermore National Laboratory, Institute of Geophysics and Planetary Physics, University of California, 7000 East Avenue, Livermore, California 94550, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Brendan McNulty 1Department of Earth Sciences, California State University Dominguez Hills, 1000 East Victoria Street, Carson, California 90747, USA Daniel Farber 2Lawrence Livermore National Laboratory, Institute of Geophysics and Planetary Physics, University of California, 7000 East Avenue, Livermore, California 94550, USA Publisher: Geological Society of America Received: 24 Sep 2001 Revision Received: 20 Feb 2002 Accepted: 26 Feb 2002 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2002) 30 (6): 567–570. https://doi.org/10.1130/0091-7613(2002)030<0567:ADFATP>2.0.CO;2 Article history Received: 24 Sep 2001 Revision Received: 20 Feb 2002 Accepted: 26 Feb 2002 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Brendan McNulty, Daniel Farber; Active detachment faulting above the Peruvian flat slab. Geology 2002;; 30 (6): 567–570. doi: https://doi.org/10.1130/0091-7613(2002)030<0567:ADFATP>2.0.CO;2 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 SocietyGeology Search Advanced Search Abstract The Cordillera Blanca detachment fault in the Peruvian Andes is, to our knowledge, the first active detachment to be documented above a modern flat slab. Crustal detachment has unroofed the ca. 8 Ma Cordillera Blanca batholith, now the backbone of the highest mountain range in Peru. Large-magnitude slip along the fault was thermally enhanced by emplacement of the batholith, the penultimate magmatic event prior to flattening of the Nazca slab. However, extensional models based on arc magmatism and crustal thickening alone do not adequately explain the scale or structural asymmetry of a series of young, deep-seated, west-dipping normal faults across Peru. Here we show that the onset of detachment faulting coincided with subduction of the aseismic Nazca Ridge and consequent flattening of the Nazca slab. We propose that slab buoyancy from ridge subduction triggered extensional collapse of the prethickened continental crust, and that this buoyancy drove footwall uplift that exceeds basin subsidence. The west-dipping asymmetry of late Cenozoic extensional faults in Peru may be controlled by a preexisting crustal anisotropy (older thrusts), and/or formation of Riedel-like shears kinematically linked to the flat Nazca slab. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.