3.96 Ga zircons from an Archean quartzite, Beartooth Mountains, Montana

Research Article| April 01, 1992 3.96 Ga zircons from an Archean quartzite, Beartooth Mountains, Montana P. A. Mueller; P. A. Mueller 1Department of Geology, University of Florida, Gainesville, Florida 32611 Search for other works by this author on: GSW Google Scholar J. L. Wooden; J. L. Wooden 2U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar A. P. Nutman A. P. Nutman 3Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia Search for other works by this author on: GSW Google Scholar Geology (1992) 20 (4): 327–330. https://doi.org/10.1130/0091-7613(1992)020<0327:GZFAAQ>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation P. A. Mueller, J. L. Wooden, A. P. Nutman; 3.96 Ga zircons from an Archean quartzite, Beartooth Mountains, Montana. Geology 1992;; 20 (4): 327–330. doi: https://doi.org/10.1130/0091-7613(1992)020<0327:GZFAAQ>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 U-Pb isotopic systematics of detrital zircons incorporated in a middle Archean quartzite from the Beartooth Mountains, Montana, were investigated with the SHRIMP ion microprobe. These new data reveal an extended and previously unrecognized record of crustal evolution for the northern Wyoming province. Seventy-eight analyses of 67 grains yielded a range of 207Pb/206Pb ages from 2.69 to 3.96 Ga. Concordant analyses from 43 separate grains define a maximum age for the deposition of the quartzite of 3.30 Ga; other provenance ages extend to 3.96 Ga. Ages of <3.30 Ga are generally discordant, and appear to reflect late Archean disturbance of the U-Pb system, including metamorphism at ∼2.8 Ga. The predominance off ages at ∼3.3 Ga is interpreted to represent the last major episode of crust formation prior to deposition of the quartzite. The concordant analyses of >3.30 Ga indicate that older crustal components with ages up to 3.96 Ga, or detritus from them, were also in the provenance of this quartzite. This older age is equivalent to that of the oldest known rock from the Acasta gneisses of the Slave province and is exceeded only by the >4.0 Ga age of detrital zircons off the Yilgarn block of Western Australia. These data support an increased probability for the survival of sialic crust created before the cessation of the late bombardment at 3.8 to 3.9 Ga. 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.