Disequilibrium partitioning of oxygen isotopes associated with sector zoning in quartz

Research Article| December 01, 1995 Disequilibrium partitioning of oxygen isotopes associated with sector zoning in quartz Charles M. Onasch; Charles M. Onasch 1Department of Geology, Bowling Green State University, Bowling Green, Ohio 43403 Search for other works by this author on: GSW Google Scholar Torsten W. Vennemann Torsten W. Vennemann 2Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109 Search for other works by this author on: GSW Google Scholar Author and Article Information Charles M. Onasch 1Department of Geology, Bowling Green State University, Bowling Green, Ohio 43403 Torsten W. Vennemann 2Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1995) 23 (12): 1103–1106. https://doi.org/10.1130/0091-7613(1995)023<1103:DPOOIA>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 Charles M. Onasch, Torsten W. Vennemann; Disequilibrium partitioning of oxygen isotopes associated with sector zoning in quartz. Geology 1995;; 23 (12): 1103–1106. doi: https://doi.org/10.1130/0091-7613(1995)023<1103:DPOOIA>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 Fractionation of oxygen isotopes during crystal growth is commonly assumed to be an equilibrium process. We present evidence here that large variations in δ18O values in a zoned vein quartz crystal are the result of disequilibrium partitioning between fluid and crystal. Within a single crystal with well-developed concentric and sector zoning, δ18O values determined with laser extraction techniques on milligram- to submilligram-sized samples range from 4.7‰ to 7.3‰. Core to rim variations within single growth sectors fluctuate by 2.6‰, whereas differences between adjacent sectors along the same growth zone can exceed 2.0‰. In contrast, fluid-inclusion homogenization temperatures and salinities are relatively constant and show no effect of growth or sector zoning. Differences in δ18O values between sectors along the same growth zone cannot result from variations in the oxygen isotope composition of the fluid and strongly suggest disequilibrium partitioning of oxygen isotopes between fluid and the growing crystal. The cause of this disequilibrium is believed to be due to differences in surface structure and/or growth mechanisms between nonequivalent faces. 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.