Displacement history of the Atacama fault system 25°00′S-27° 00′S, northern Chile

Research Article| September 01, 1993 Displacement history of the Atacama fault system 25°00′S-27° 00′S, northern Chile M. BROWN; M. BROWN 1Department of Geology, University of Maryland at College Park, Maryland 20742 Search for other works by this author on: GSW Google Scholar F. DIÁZ; F. DIÁZ 2Servicio Nacional de Geología y Minería, Casilla 10465, Santiago, Chile Search for other works by this author on: GSW Google Scholar J. GROCOTT J. GROCOTT 3School of Geological Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, United Kingdom Search for other works by this author on: GSW Google Scholar Author and Article Information M. BROWN 1Department of Geology, University of Maryland at College Park, Maryland 20742 F. DIÁZ 2Servicio Nacional de Geología y Minería, Casilla 10465, Santiago, Chile J. GROCOTT 3School of Geological Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, United Kingdom Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1993) 105 (9): 1165–1174. https://doi.org/10.1130/0016-7606(1993)105<1165:DHOTAF>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation M. BROWN, F. DIÁZ, J. GROCOTT; Displacement history of the Atacama fault system 25°00′S-27° 00′S, northern Chile. GSA Bulletin 1993;; 105 (9): 1165–1174. doi: https://doi.org/10.1130/0016-7606(1993)105<1165:DHOTAF>2.3.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 SocietyGSA Bulletin Search Advanced Search Abstract In the Cordillera de la Costa of the central Andes in northern Chile, Mesozoic arc complexes are cut by a trench-parallel strike-slip fault system: the Atacama fault system. Brittle faulting in the Atacama fault system is superposed on steeply dipping foliations in ductile shear belts. Between 25°S and 27°S, the western part of the fault system was active in Early Cretaceous time as an upper amphibolite facies, down-to-the-east, dip-slip ductile shear zone. In the eastern part of the fault system, ductile deformation is of similar Early Cretaceous age but occurred under lower-grade metamorphic conditions at the greenschist/lower amphibolite facies transition. The mylonites in the eastern part of the fault system were formed by sinistral strike-slip displacement.The dip-slip and sinistral strike-slip displacements are contemporary with the development of a magmatic arc, and they imply that the tectonic environment in this part of the arc was transtensional. The ductile deformation was partitioned spatially into a dip-slip component associated with the emplacement of magmas and a sinistral strike-slip component.Brittle fault zones in the El Salado segment of the Atacama fault system define large-scale sidewall ripout structures. Subhorizontai slickenlines, ripout asymmetry, and S-C-type fabrics in fault gouge indicate that brittle deformation involved sinistral strike-slip displacements. The transition from ductile to brittle sinistral strike-slip displacements may have occurred due to cooling, in mid-Cretaceous time, when the magmatic arc was abandoned. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.