Metamorphism and exhumation of basement gneiss domes in the Quadrilátero Ferrífero:Two stage dome-and-keel evolution?

作     者：Kathryn Cutts Cristiano Lana Fernando Alkmim Federico Farina Hugo Moreira Viviane Coelho 

作者机构：Applied Isotope Research GroupDepartamento de GeologiaEscola de MinasUniversidade Federal de Ouro PretoMorro do Cruzeiro35400-000Ouro PretoMGBrazil Department of Earth SciencesUniversity of GenevaRue des Maraihers 131205GenevaSwitzerland School of Earth and Environmental SciencesUniversity of PortsmouthBurnaby BuildingBurnaby RoadPortsmouthPO1 3QLUK 

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

年 卷 期：2019年第10卷第5期

页      面：1765-1787页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：benefited from FAPEMIG(APQ03943,APQ-0379316 and RPQ 00067-10)grants CNPq for her Science without Borders,Jovem Talento Scholarship funding from Edital UFOP/Auxilio Pesquisador 2015 funding from CNPq grant(30804/2013-0) CNPq Scholarship(234610/2014-0) funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No.701494 

主　　题：Sao Francisco Craton Zircon U-Pb Titanite U-Pb Phase diagrams Dome-and-keel 

摘      要：The presence of dome-and-keel provinces in Archean cratons has been connected with the initiation of plate tectonics on Earth as these features are most commonly observed in Archean *** Quadrilátero Ferrífero in Brazil has been identified as a Paleoproterozoic dome-and-keel province for more than three *** prevailing model suggests that it formed during the Rhyacian Transamazonian orogeny,making it unique among dome-and-keel ***,a lack of appropriate lithologies,datable minerals and the metamorphic overprint of later orogenesis has resulted in a cryptic metamorphic record for the formation of this dome-and-keel province.A clinopyroxene-bearing migmatite from the core of the Bacao dome has peak P-T conditions of 5-7 kbar and 700-750 ℃ and a published age of ca.2730 Ma based on U-Pb ages of zircon from leucosomes,suggesting that this age represents the migmatisation event.A fine-grained epidote-albite-titanite assemblage overprints the coarse-grained clinopyroxene and amphibole,giving P-T conditions of 8-9 kbar and 550℃ with an associated titanite age of ca.2050 Ma.A garnet-bearing amphibolite sample also from the core of the dome has peak P-T conditions of 7-8 kbar and 650-700℃,and texturally late titanite from this sample produces an age of ca.2060 *** additional samples were collected from the edges of the dome.A garnet-gedrite bearing felsic schist produces peak P-T conditions of 8-9 kbar and 650-700℃ on a clockwise P-T *** sample has a U-Pb zircon age of ca.2775 Ma,which could date metamorphism or be the age of its volcaniclastic *** unconstrained titanite from the sample gives an age of ca.2040 Ma.A garnet-bearing amphibolite that occurs as a boudin within the felsic schist gives both zircon and titanite ages of ca.2050 Ma and has peak P-T conditions of 5-6 kbar and 650-700 ℃ on a near isobaric P-T *** amphibolite dike,observed to cross-cut the felsic schist produces a zircon U-Pb age of ca.2760 Ma