Deepest exposed crust of Brazil-SHRIMP establishes three events

Abstract

Research Article| October 01, 1999 Deepest exposed crust of Brazil-SHRIMP establishes three events Léo A. Hartmann; Léo A. Hartmann 1Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, 91500-000 Porto Alegre, Rio Grande do Sul, Brazil Search for other works by this author on: GSW Google Scholar Jayme A. D. Leite; Jayme A. D. Leite 2Departamento de Recursos Minerais, Universidade Federal de Mato Grosso, Avenida Fernando Correa da Costa s/n, Cuiabá, Mato Grosso, Brazil Search for other works by this author on: GSW Google Scholar Neal J. McNaughton; Neal J. McNaughton 3Centre for Strategic Mineral Deposits, University of Western Australia, Nedlands 6907, Western Australia Search for other works by this author on: GSW Google Scholar João Orestes S. Santos João Orestes S. Santos 4Geological Survey of Brazil (CPRM), Rua Banco da Provìncia, 105, Porto Alegre, Rio Grande do Sul, Brazil Search for other works by this author on: GSW Google Scholar Geology (1999) 27 (10): 947–950. https://doi.org/10.1130/0091-7613(1999)027<0947:DECOBS>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 MailTo Tools Icon Tools Get Permissions Search Site Citation Léo A. Hartmann, Jayme A. D. Leite, Neal J. McNaughton, João Orestes S. Santos; Deepest exposed crust of Brazil-SHRIMP establishes three events. Geology 1999;; 27 (10): 947–950. doi: https://doi.org/10.1130/0091-7613(1999)027<0947:DECOBS>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 The deepest exposed crust of Brazil is in the western portion of the exposed Precambrian shield of southernmost Rio Grande do Sul State and comprises a bimodal sequence of mafic garnet granulites and metatrondhjemites, intercalated with smaller volumes of metamorphosed pyroxenites, anorthosites, sillimanite gneisses, and banded iron formation. As determined by zircon U/Pb sensitive high-resolution ion microprobe (SHRIMP), this granulite terrain accreted from the mantle at the end of the Archean (ca. 2.55 Ga) and was deformed in high-pressure granulite facies metamorphic conditions in the Paleoproterozoic (ca. 2.02 Ga). A younger event, possibly ca. 900 Ma, caused local amphibolite facies retrogression in the complex. Zircons from a metabasalt and a metatrondhjemite show external morphologies typical of high-grade metamorphic rocks, whereas backscattered electron images reveal internal oscillatory zoning of their igneous precursors. Spot ages from zircon agree well with previous model Nd and Sm/Nd mineral isochron ages. 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.