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标题：Reappraisal of the Sumé Complex: geochemistry and geochronology of metaigneous rocks and implications for Paleoproteorozoic subduction-accretion events in the Borborema Province, NE Brazil
其他标题：Reappraisal of the Sumé Complex: geochemistry and geochronology of metaigneous rocks and implications for Paleoproteorozoic subduction-accretion events in the Borborema Province, NE Brazil
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作者：Santos, Edilton José dos ; Santos, Lauro Cézar Montefalco de Lira
期刊名称：Brazilian Journal of Geology
印刷版ISSN：2317-4889
出版年度：2019
卷号：49
期号：1
页码：1-14
DOI：10.1590/2317-4889201920180083
出版社：Sociedade Brasileira de Geologia
摘要：The Alto Moxotó Terrane represents the largest exposure of Paleoproterozoic rocks in the central Borborema Province. Several medium- to high-grade metamorphic units are described in the terrane, however geochronological data are still scarce, and the main periods of crust build-up and recycling are poorly known. In this study, we investigate the nature and age of metagranitic and metamafic-ultramafic rocks in the type area of the Sumé Complex. U-Pb zircon data from a metasyenogranite yields a concordant age of 1.97 Ga, which is in contrast with the previously published age of the complex (c. 640 Ma). In addition, Sm-Nd isotope signature indicates Paleoproterozoic to Mesoarchean sources that coupled with negative εNd(t) values suggest reworking of a preexisting crust. Whole-rock geochemical data indicate that metamafic rocks are similar to those already described in the terrane, corresponding to island-arc tholeiites, whereas the metagranitic rocks share similarities with magmas that were generated in an evolved stage of an orogenic setting. The obtained results are coherent with a long-lived Paleoproterozoic accretionary-collisional event (c. 2.1 - 1.9 Ga) described in the Borborema Province, which is correlative with Paleoproterozoic (c. 2.2 - 2.0 Ga) basement inliers/terranes from Pan-African Fold belts..
关键词：Sumé Complex; Accretion tectonics; Alto Moxotó Terrane; Borborema Province; Western Gondwana.
其他关键词：Sumé Complex;Accretion tectonics;Alto Moxotó Terrane;Borborema Province;Western Gondwana