Olivine Compositions and Cooling Rates of Pallasitic Meteorites

Research Article| November 01, 1969 Olivine Compositions and Cooling Rates of Pallasitic Meteorites PETER R BUSECK; PETER R BUSECK Departments of Geology and Chemistry, Arizona State University, Tempe, Arizona 85281 Search for other works by this author on: GSW Google Scholar JOSEPH I GOLDSTEIN JOSEPH I GOLDSTEIN Planetology Branch, NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771 PRESENT ADDRESS (GOLDSTEIN): METALLURGY AND MATERIALS SCIENCE DEPARTMENT, LE-HIGH UNIVERSITY, BETHLEHEM, PENNSYLVANIA Search for other works by this author on: GSW Google Scholar Author and Article Information PETER R BUSECK Departments of Geology and Chemistry, Arizona State University, Tempe, Arizona 85281 JOSEPH I GOLDSTEIN PRESENT ADDRESS (GOLDSTEIN): METALLURGY AND MATERIALS SCIENCE DEPARTMENT, LE-HIGH UNIVERSITY, BETHLEHEM, PENNSYLVANIA Planetology Branch, NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771 Publisher: Geological Society of America Received: 18 Sep 1968 Revision Received: 04 Mar 1969 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1969, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1969) 80 (11): 2141–2158. https://doi.org/10.1130/0016-7606(1969)80[2141:OCACRO]2.0.CO;2 Article history Received: 18 Sep 1968 Revision Received: 04 Mar 1969 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation PETER R BUSECK, JOSEPH I GOLDSTEIN; Olivine Compositions and Cooling Rates of Pallasitic Meteorites. GSA Bulletin 1969;; 80 (11): 2141–2158. doi: https://doi.org/10.1130/0016-7606(1969)80[2141:OCACRO]2.0.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 Electron microprobe measurements of olivine and metal in about 85 percent of the known pallasites were made. The olivines are unzoned, and coexisting crystals within most pallasites have identical compositions. This indicates a high degree of internal equilibrium. Relative to terrestrial olivines, pallasitic olivines are depleted in Ni. Thermochemical calculations demonstrate that the low Ni contents of pallasitic olivines are consistent with metal-olivine equilibrium at 1000° C or less. Cooling rate measurements show that the pallasites cooled more slowly (0.5° to 2.0° C per million years) than the bulk of the iron meteorites and that the pallasites form a homogeneous cooling rate group.Application of a modified Prior's rule to the pallasites suggests that olivine and metal equilibrated in the presence of other silicates. The observed compositional distribution of olivine from pallasites is compatible with that predicted from a chondritic parent melt. The pallasites were probably derived from deep within their parent body, either at or near the core. Most iron meteorites were either formed from different parent bodies or came from isolated metal pools within the silicate mantle. 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.