Mineralogy and Petrology of the Iron Hill Carbonatite Complex, Colorado

Research Article| May 01, 1972 Mineralogy and Petrology of the Iron Hill Carbonatite Complex, Colorado W. P NASH W. P NASH Department of Geological and Geophysical Sciences, University of Utah, Salt Lake City, Utah 84112 Search for other works by this author on: GSW Google Scholar Author and Article Information W. P NASH Department of Geological and Geophysical Sciences, University of Utah, Salt Lake City, Utah 84112 Publisher: Geological Society of America Received: 12 Jul 1971 Revision Received: 01 Nov 1971 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1972, 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 (1972) 83 (5): 1361–1382. https://doi.org/10.1130/0016-7606(1972)83[1361:MAPOTI]2.0.CO;2 Article history Received: 12 Jul 1971 Revision Received: 01 Nov 1971 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 W. P NASH; Mineralogy and Petrology of the Iron Hill Carbonatite Complex, Colorado. GSA Bulletin 1972;; 83 (5): 1361–1382. doi: https://doi.org/10.1130/0016-7606(1972)83[1361:MAPOTI]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 Bulk rock and mineral chemistry of the rock types occurring in the Iron Hill carbonatite complex have been examined in order to determine the genetic link between carbonatites and the alkaline igneous rocks with which they are ubiquitously associated. A variety of silicate rock types, including pyroxenite, uncom-pahgrite, ijolite, and nepheline syenite is developed at Iron Hill. The carbonatites are composed dominantly of calcite, ankeritic dolomite, or siderite. Only a rare variety of calcite carbonatite contains significant amounts of silicate minerals.Silicate minerals in the calcite carbonatite are generally intermediate in composition to those occurring in ijolite and nepheline syenite. These data, together with the scarcity of rock types gradational between silicate and carbonate varieties, suggest the possible separation of a discrete carbonate fluid phase during the latter part of the crystallization of the silicate series postdating formation of the ijolite but prior to the crystallization of the nepheline syenites.Calcite-dolomite and pyrite-pyrrhotite pairs indicate temperatures of crystallization of late-stage carbonatites of the order of 435° C to 290° C at sulfur fugacities of 10−7.8b and oxygen fugacities of the order of 10−25 to 10−26b. 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.