Tectonic trigger for the formation of late Miocene Cu-rich breccia pipes in the Andes of central Chile

Research Article| June 01, 1994 Tectonic trigger for the formation of late Miocene Cu-rich breccia pipes in the Andes of central Chile M. Alexandra Skewes; M. Alexandra Skewes 1Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309 Search for other works by this author on: GSW Google Scholar Charles R. Stern Charles R. Stern 1Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309 Search for other works by this author on: GSW Google Scholar Author and Article Information M. Alexandra Skewes 1Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309 Charles R. Stern 1Department of Geological Sciences, University of Colorado, Boulder, Colorado 80309 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1994) 22 (6): 551–554. https://doi.org/10.1130/0091-7613(1994)022<0551:TTFTFO>2.3.CO;2 Article history 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 M. Alexandra Skewes, Charles R. Stern; Tectonic trigger for the formation of late Miocene Cu-rich breccia pipes in the Andes of central Chile. Geology 1994;; 22 (6): 551–554. doi: https://doi.org/10.1130/0091-7613(1994)022<0551:TTFTFO>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 SocietyGeology Search Advanced Search Abstract During the late Miocene, the decreasing angle of subduction below the Andes of central Chile caused a reduction in the influx of new magma and heat into the base of magmatic systems that had been active throughout the Miocene. This led to their cooling and solidification, triggering the release of large volumes of metal-rich magmatic fluids from middle- and upper-crustal magma chambers and generating a group of economically significant Cu-rich breccia pipes. The Sr- and Nd-isotopic compositions of the magmatic fluids that formed these brecccas, determined from breccia-matrix minerals, were variable, implying that these fluids were not exsolved from a specific Cu-porphyry magma, as is often invoked to explain Andean Cu deposits. Instead, the formation of the late Miocene deposits in central Chile was tectonically triggered by cooling of a variety of magma types during the last stages of existence of long-lived Andean magmatic systems as both subduction angle and, as a result, subarc magma supply decreased. 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.