Potassic volcanism near Mono basin, California: Evidence for high water and oxygen fugacities inherited from subduction

Research Article| October 01, 1993 Potassic volcanism near Mono basin, California: Evidence for high water and oxygen fugacities inherited from subduction Rebecca A. Lange; Rebecca A. Lange 1Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109 Search for other works by this author on: GSW Google Scholar Ian S. E. Carmichael; Ian S. E. Carmichael 2Department of Geology and Geophysics, University of California, Berkeley, California 94720 Search for other works by this author on: GSW Google Scholar Paul R. Renne Paul R. Renne 3Institute of Human Origins Geochronology Center, 2453 Ridge Road, Berkeley, California 94709 Search for other works by this author on: GSW Google Scholar Author and Article Information Rebecca A. Lange 1Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109 Ian S. E. Carmichael 2Department of Geology and Geophysics, University of California, Berkeley, California 94720 Paul R. Renne 3Institute of Human Origins Geochronology Center, 2453 Ridge Road, Berkeley, California 94709 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1993) 21 (10): 949–952. https://doi.org/10.1130/0091-7613(1993)021<0949:PVNMBC>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 Rebecca A. Lange, Ian S. E. Carmichael, Paul R. Renne; Potassic volcanism near Mono basin, California: Evidence for high water and oxygen fugacities inherited from subduction. Geology 1993;; 21 (10): 949–952. doi: https://doi.org/10.1130/0091-7613(1993)021<0949:PVNMBC>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 Exposed around the margins of Mono basin and the periphery of Long Valley caldera are ∼100 km3 of potassic, basic to intermediate lavas that record high water and oxygen fugacities. Most eruptions occurred between 4 and 2 Ma, although sporadic potassic volcanism continued into the Quaternary with a pulse between 0.1 and 0.5 Ma, ∼15 km northeast of Mono basin. The lava types include absarokite, minette, hornblende lamprophyre, trachybasalt, and trachyandesite. Estimated water contents for lavas without hydrous phenocrysts range between 2 and 3 wt% considerably more than mid-ocean ridge, oceanic island, or back-arc magmas. Calculated fO2, values fall between -0.4 and +1.2 log units of the Ni-NiO buffer. Although this potassic suite was erupted in an extensional tectonic setting at the western margin of the Basin and Range province, its high K2O/TiO2 and low Zr/Ba ratios suggest a subduction-modified mantle source. If subduction was the process that enriched the lithospheric mantle in large-ion lithophile elements (K, Ba, etc.), it was also a mechanism for mantle oxidation and hydration. 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.