Record of Early Tonian mafic magmatism in the central Espinhaco(Brazil):New insights for break-up of the Neoproterozoic landmass ancestor of Sao Francisco-Congo paleocontinent

作     者：Helen F.Moreira AndréDanderfer Alice F.O.Costa Samuel M.Bersan Cristiano C.Lana Gláucia N.Queiroga Helen F. Moreira;André Danderfer;Alice F.O. Costa;Samuel M. Bersan;Cristiano C. Lana;Gláucia N. Queiroga

作者机构：Post Graduate Program of Department of GeologyMine SchoolFederal University of Ouro PretoBrazil Department of GeologyMine SchoolFederal University of Ouro PretoBrazil 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2020年第11卷第6期

页      面：2323-2337页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：CAPES,FAPEMIG(APQ-00125-12)and Petrobras(Geotectonic Studies Network)for financial support the Universidade Federal de Ouro Preto and CDTN(Centro de Desenvolvimento da Tecnologia Nuclear)for institutional support 

主　　题：Mafic rocks Espinhaco basin Sao Francisco-Congo paleocontinent Tonian rifting U–Pb geochronology 

摘      要：Petrological characterization,U-Pb geochronology,Lu-Hf analyses and major and trace element data from mafic intrusions in the Central Espinhaco(central portion of the Brazilian shield)are used here to investigate the geological significance of the Early Neoproterozoic magmatism in the context of the Sao Francisco-Congo *** mafic bodies are represented by medium to coarse-grained metagabbros with plagioclase,amphibole and *** U-Pb isotopic data from two samples yielded weighted mean 206pb/238U ages of 895±3.4 Ma(MSWD=1.7)and 896±2.4 Ma(MSWD=0.64),regarded as the best estimates for the crystallization age of these mafic *** and trace element data(including REEs)show that the gabbros originated from a subalkaline tholeiitic magma,typical of intraplate *** rocks are slightly enriched in LREEs and LILEs and depleted in *** new isotope and geochemical data,along with regional knowledge,indicate that these metagabbros mark the beginning of an important Tonian-age extensional tectonic event of the landmass of which the Sao Francisco-Congo paleocontinent was part(Rodinia supercontinent or Central African block?).We furthermore suggest that these rocks belong to a prominent suite of Tonian-age mafic rocks that mark a diachronic breakup attempt of this landmass which may have occurred from south to north along the Espinhaco mountain range.