Tertiary tectonic history of the southern Andes: The subvolcanic sequence to the Tatara–San Pedro volcanic complex, lat 36°S

Abstract

Research Article| September 01, 1999 Tertiary tectonic history of the southern Andes: The subvolcanic sequence to the Tatara–San Pedro volcanic complex, lat 36°S Stephen T. Nelson; Stephen T. Nelson 1Department of Geology, Brigham Young University, Provo, Utah 84602 Search for other works by this author on: GSW Google Scholar Jon P. Davidson; Jon P. Davidson 2Department of Earth and Space Sciences, University of California, Los Angeles, California 90095 Search for other works by this author on: GSW Google Scholar Matthew T. Heizler; Matthew T. Heizler 3New Mexico Bureau of Mines and Mineral Resources, Campus Station, Socorro, New Mexico 87801 Search for other works by this author on: GSW Google Scholar Bart J. Kowallis Bart J. Kowallis 1Department of Geology, Brigham Young University, Provo, Utah 84602 Search for other works by this author on: GSW Google Scholar Author and Article Information Stephen T. Nelson 1Department of Geology, Brigham Young University, Provo, Utah 84602 Jon P. Davidson 2Department of Earth and Space Sciences, University of California, Los Angeles, California 90095 Matthew T. Heizler 3New Mexico Bureau of Mines and Mineral Resources, Campus Station, Socorro, New Mexico 87801 Bart J. Kowallis 1Department of Geology, Brigham Young University, Provo, Utah 84602 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1999) 111 (9): 1387–1404. https://doi.org/10.1130/0016-7606(1999)111<1387:TTHOTS>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 MailTo Tools Icon Tools Get Permissions Search Site Citation Stephen T. Nelson, Jon P. Davidson, Matthew T. Heizler, Bart J. Kowallis; Tertiary tectonic history of the southern Andes: The subvolcanic sequence to the Tatara–San Pedro volcanic complex, lat 36°S. GSA Bulletin 1999;; 111 (9): 1387–1404. doi: https://doi.org/10.1130/0016-7606(1999)111<1387:TTHOTS>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 The Tatara–San Pedro volcanic complex, a Quaternary to Holocene composite volcano in central Chile, is underlain by late Miocene (6 Ma) plutons and Tertiary metavolcanic rocks. The plutons were intruded into greenschist facies metavolcanic rocks at a depth of about 4–5 km. Together, these rocks reveal important information about the development of continental arcs.In some cases, apparent eruptive ages of metavolcanic rocks are younger than ages of intruding plutons, indicating that there was (1) pervasive reheating of metavolcanic rocks or (2) that metavolcanic rocks were locally derived and intruded by their own magma chambers (plutons). We have estimated uplift or denudation rates of nearly 1 mm/yr since late Miocene time. Normal faulting currently dominates the brittle behavior of the upper crust; therefore, uplift is probably related to magmatic addition to the crust rather than to compression and shortening. Although plutonic and metavolcanic rocks display expected arc geochemical affinities, the isotopic similarity of metavolcanic and plutonic rocks to Quaternary volcanic rocks is strong; this makes it difficult to use subvolcanic rocks as upper crustal contaminants to evaluate the igneous evolution of the Quaternary deposits. Most plutonic, metavolcanic, and Quaternary volcanic rocks exhibit the isotopic characteristics of juvenile crust. Some samples, however, exhibit sparse but unmistakable evidence (87Sr/86Sr and 40Ar/39Ar isotopic data) for the presence of older, probably Precambrian through Triassic radiogenic crust beneath the volcano.Crustal structure in this arc can be described by a three-layer model in which a central section of Precambrian through Triassic rock is underplated by juvenile material, is intruded by juvenile material, or has juvenile material transported through it to be emplaced at or near the surface. Continued erosion of juvenile material at the surface may be balanced to some degree by continued volcanism and epizonal plutonism. 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.