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Paleogeographic implications of non–North American sediment in the Mesoproterozoic upper Belt Supergroup and Lemhi Group, Idaho and Montana, USA

2010; Geological Society of America; Volume: 38; Issue: 10 Linguagem: Inglês

10.1130/g31194.1

1943-2682

Eric D. Stewart, Paul K. Link, C. Mark Fanning, Carol D. Frost, Michael McCurry,

Geology and Paleoclimatology Research

Research Article| October 01, 2010 Paleogeographic implications of non–North American sediment in the Mesoproterozoic upper Belt Supergroup and Lemhi Group, Idaho and Montana, USA Eric D. Stewart; Eric D. Stewart * 1Department of Geosciences, Idaho State University, Pocatello, Idaho 83209, USA *E-mail: steweric@isu.edu. Search for other works by this author on: GSW Google Scholar Paul K. Link; Paul K. Link 1Department of Geosciences, Idaho State University, Pocatello, Idaho 83209, USA Search for other works by this author on: GSW Google Scholar C. Mark Fanning; C. Mark Fanning 2Research School of Earth Sciences, Australian National University, Canberra, ACT 5000, Australia Search for other works by this author on: GSW Google Scholar Carol D. Frost; Carol D. Frost 3Department of Geology, University of Wyoming, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar Michael McCurry Michael McCurry 1Department of Geosciences, Idaho State University, Pocatello, Idaho 83209, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Eric D. Stewart * 1Department of Geosciences, Idaho State University, Pocatello, Idaho 83209, USA Paul K. Link 1Department of Geosciences, Idaho State University, Pocatello, Idaho 83209, USA C. Mark Fanning 2Research School of Earth Sciences, Australian National University, Canberra, ACT 5000, Australia Carol D. Frost 3Department of Geology, University of Wyoming, Laramie, Wyoming 82071, USA Michael McCurry 1Department of Geosciences, Idaho State University, Pocatello, Idaho 83209, USA *E-mail: steweric@isu.edu. Publisher: Geological Society of America Received: 08 Mar 2010 Revision Received: 12 May 2010 Accepted: 21 May 2010 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2010 Geological Society of America Geology (2010) 38 (10): 927–930. https://doi.org/10.1130/G31194.1 Article history Received: 08 Mar 2010 Revision Received: 12 May 2010 Accepted: 21 May 2010 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Eric D. Stewart, Paul K. Link, C. Mark Fanning, Carol D. Frost, Michael McCurry; Paleogeographic implications of non–North American sediment in the Mesoproterozoic upper Belt Supergroup and Lemhi Group, Idaho and Montana, USA. Geology 2010;; 38 (10): 927–930. doi: https://doi.org/10.1130/G31194.1 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 A non-North American provenance for the lower Belt Supergroup of North America has been used to support various pre-Rodinian paleogeographic reconstructions. Unlike the lower Belt Supergroup, most upper Belt Supergroup provenance studies have inferred Laurentian sediment sources. We test this hypothesis by analyzing U-Pb and Lu-Hf isotopes on detrital zircons, and whole-rock Nd isotopes from the Missoula (upper Belt Supergroup) and Lemhi Groups, and comparing to possible Laurentian sources. Detrital zircons from 11 sandstones analyzed show dominant ages between 1680 and 1820 Ma. These zircons are predominantly magmatic in paragenesis. Belt Supergroup–aged (1400–1470 Ma) and 2400–2700 Ma populations represent minor components. Lu-Hf isotopic analyses for 1675–1780 Ma Missoula Group and Lemhi Group detrital zircons range from εHf(i) +9 to –12 and +8 and –7, respectively. Belt Supergroup–aged grains from the Bonner Formation, Missoula Group, have εHf(i) values between +5 and –9, exceeding coeval ranges from the Mojave and Yavapai terranes [εHf(i) between +5 and 0]. Whole-rock Nd isotopes from Lemhi Group argillites yield a range in εNd(1400) between +1.1 and –5.9. Immature feldspathic sediment, nearly unimodal detrital zircon spectra, and dissimilar Belt Supergroup–aged zircon Hf signatures suggest that distal portions of the Yavapai and Mojave terranes intruded by A-type magmas were not the source for the Missoula and Lemhi Groups. Instead, a slightly modified Mesoproterozoic proto-SWEAT (southwestern United States and East Antarctica) model can best account for the sedimentologic and isotopic characteristics of the Missoula and Lemhi Groups. An alternative model with a source from southeastern Siberia and the Okhotsk Massif is less preferred. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.