Linking sedimentary provenance,climate and tectonics in the Neoproterozoic SeridóBelt,Borborema Province(NE Brazil)  

作　　者：Carlos V.A.Ribeiro Marcos C.C.Sales Armando L.S.de Oliveira Ricardo Sallet 

机构地区：[1]Programa de Pós-graduação em Geologia,Instituto de Geociências,Universidade de Brasília(UnB),CEP 70910-900 Brasília,DF,Brazil [2]Programa de Pós-Graduação em Geociências,Universidade Federal de Pernambuco,Departamento de Geologia,Centro de Tecnologia e Geociências,Av.da Arquitetura,CEP 50740-530 Recife,PE,Brazil [3]Departamento de Geologia,Universidade Federal do Rio Grande do Norte,CEP 59078-970 Natal,RN,Brazil

出　　处：《Geoscience Frontiers》2023年第6期414-431,共18页地学前缘（英文版）

摘　　要：The SeridóBelt,at the extreme northeast of Brazil,is one of the several Neoproterozoic mobile belts related to the Brasiliano/Pan-African Orogeny in Western Gondwana.The lithostratigraphy of the SeridóBelt comprises basal quartzites and metaconglomerates(Equador Formation)overlain by hornblende-bearing paragneisses,calc-silicate rocks and marbles(Jucurutu Formation)and biotiteschists(SeridóFormation).We investigated the sedimentary provenance of these rocks based on an integration of compiled whole-rock geochemistry,Sm-Nd isotopes,U-Pb detrital zircon ages and a new set of whole-rock trace elements analyses.Equador Formation quartzites have major and trace elements patterns that resemble cratonic sandstones,with a typical felsic provenance consistent with the isotopic composition of plutonic Archean to Paleoproterozoic basement rocks.Geochemical proxies suggest that these rocks were deposited in fresh waters under anoxic conditions and moderate to intense weathering conditions(CIA=58–79).A shift in provenance led to an increase in intermediate-mafic sources during the deposition of the Jucurutu and Seridóformations.Trace elements from rock types in these units are nearly identical,yet they differ on the contents of some high field-strength elements(e.g.,Sc,V and Ni),which are higher in the SeridóFormation than average pelites.Geochemical proxies show similar depositional environments,with brackish to marine conditions for the Jucurutu and Seridóformations under anoxic to euxinic conditions.Weathering conditions are consistently lower in the Jucurutu Formation(CIA=58–66)in comparison with the SeridóFormation(CIA=60–88).Compiled U-Pb data suggest maximum depositional ages of 633±11 Ma and 633±6 Ma for Jucurutu and Seridóformations,respectively,suggesting deposition following the ca.645–635 Ma Marinoan glaciation.We compared the geochemistry of the SeridóFormation schists with currently exposed basement rocks and showed a strong affinity with Neoproterozoic arc-related intermediate rocks,which is

关 键 词：Whole-rock geochemistry Marinoan Glaciation U-Pb detrital zircon Brasiliano Orogeny 

分 类 号：P597[天文地球—地球化学] P542.2[天文地球—地质学]