Fluids in the lower crust following Mendocino triple junction migration: Active basaltic intrusion?

Abstract

Research Article| February 01, 1998 Fluids in the lower crust following Mendocino triple junction migration: Active basaltic intrusion? Alan Levander; Alan Levander 1Geology and Geophysics Department, Rice University, Houston, Texas 77005 Search for other works by this author on: GSW Google Scholar Timothy J. Henstock; Timothy J. Henstock 1Geology and Geophysics Department, Rice University, Houston, Texas 77005 Search for other works by this author on: GSW Google Scholar Anne S. Meltzer; Anne S. Meltzer 2Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015-3188 Search for other works by this author on: GSW Google Scholar Bruce C. Beaudoin; Bruce C. Beaudoin 2Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015-3188 Search for other works by this author on: GSW Google Scholar Anne M. Trehu; Anne M. Trehu 3Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015-3188 Search for other works by this author on: GSW Google Scholar Simon L. Klemperer Simon L. Klemperer 4College of Oceanographic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331-5503 Search for other works by this author on: GSW Google Scholar Author and Article Information Alan Levander 1Geology and Geophysics Department, Rice University, Houston, Texas 77005 Timothy J. Henstock 1Geology and Geophysics Department, Rice University, Houston, Texas 77005 Anne S. Meltzer 2Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015-3188 Bruce C. Beaudoin 2Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015-3188 Anne M. Trehu 3Department of Earth and Environmental Sciences, Lehigh University, Bethlehem, Pennsylvania 18015-3188 Simon L. Klemperer 4College of Oceanographic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331-5503 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1998) 26 (2): 171–174. https://doi.org/10.1130/0091-7613(1998)026<0171:FITLCF>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 Email Permissions Search Site Citation Alan Levander, Timothy J. Henstock, Anne S. Meltzer, Bruce C. Beaudoin, Anne M. Trehu, Simon L. Klemperer; Fluids in the lower crust following Mendocino triple junction migration: Active basaltic intrusion?. Geology 1998;; 26 (2): 171–174. doi: https://doi.org/10.1130/0091-7613(1998)026<0171:FITLCF>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 Geodynamic and plate tectonic models for the Mendocino triple junction, a fault-fault-trench triple junction in northwestern California, predict a slab-free zone south of the triple junction in which asthenospheric mantle upwells to the base of the crust. A variety of geological and geophysical data support this model, although fine-scale (<20 km) details of the lithospheric structure have been unknown previously. Seismic investigations in the onshore transform regime south of the Mendocino triple junction region reveal very strong short-offset reflections from the lower crust and at the crust-mantle boundary beneath the entire width of the Coast Range, particularly near Lake Pillsbury, California. Seismic analysis suggests that these reflections are from discrete zones of fluid. The reflector geometry implies that the source of the fluid is within the upper mantle. In this tectonic context it is likely that the fluids are largely partial melt, segregated from asthenospheric mantle upwelling into the slab-free zone. The tectonic setting and the location of Lake Pillsbury relative to the estimated position of the southern edge of the Gorda slab and the Clear Lake volcanic field suggest that volcanism may initiate in this region within the next 400 k.y. 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.