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Late Cryogenian-Ediacaran magmatism in southern Borborema Province,NE Brazil:Ages,sources,petrogenesis,and tectonic setting

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Geoscience Frontiers 2023年第6期14卷 70-101页

作者： Fábio Santos Pereira Herbet Conceição Maria de Lourdes Silva Rosa Moacyr Moura Marinho colombo celso gaeta tassinari João Marinho Milhomem Neto Jean-Michel Lafon Programa de Pós-Graduação em Geologia e Geoquímica(PPGG) Instituto de GeociênciasUniversidade Federal do Pará(UFPA)66075-110 BelémParáBrazil Programa de Pós-Graduação em Geociências e Análise de Bacias(PGAB) Universidade Federal de Sergipe(UFS)49100-000 São CristóvãoSergipeBrazil Instituto de Geociências Universidade Federal da Bahia(UFBA)40170-290 SalvadorBahiaBrazil Instituto de Geociências Universidade de São Paulo(USP)05508-900 São PauloBrazil Laboratório de Geologia Isotópica(Pará-Iso) IG-UFPA66075-110 BelémParáBrazil

The Sergipano Orogenic System(SOS)in southern Borborema Province(NE Brazil)hosts voluminous Neoproterozoic plutonism related to the Brasiliano/Pan-African *** paper presents comprehensive whole-rock geochemical data,titanite U-Pb ages,and the first combined zircon U-Pb and Lu-Hf isotope results for plutonic rocks from the MacururéDomain to constrain their sources,petrogenesis,and tectonic *** magmatic episodes are recognized and record the evolutionary stages of the orogen.(i)Early-collisional magmatism(643–628 Ma)comprises gabbros and diorites with minor tonalites characterized by well-developed tectonic foliation and evidence of solid-state *** rocks are magnesian,high-K calc-alkaline,LILE-and LREE-enriched and provide subchondriticε_(Hf)(t)values(6.5 to4.7)and Orosirian Hf-T^(C)_(DM)model ages(1.83–1.94 Ga).Such features indicate derivation from a lithospheric mantle source metasomatized by incorporating crustal components through subduction processes prior to magma generation,possibly related to the Rhyacian Orogeny(2.20–1.96 Ga).Extensive mixing/mingling between basaltic and crust-derived magmas took place at lower crustal depths,producing coeval hybrid diorites and quartz-diorites.(ii)Syn-collisional magmatism(630–624 Ma)encompasses biotite-and muscovite-bearing granodiorites and monzogranites,preserving their structures parallel to the schistosity of the country *** rocks are leucocratic,weakly metaluminous to peraluminous,and contain abundant surmicaceous *** features and geochemical composition suggest an origin related to the partial melting of graywacke protoliths with a subordinate igneous component.(iii)Late-collisional magmatism(625–600 Ma)includes undeformed and isotropic monzonites and granodiorites,which truncate the regional *** rocks are consistently metaluminous and magnesian,showing affinities with the high-K calc-alkaline to shoshonite *** element modeling with su

关键词： Brasiliano/Pan-African Orogeny Western Gondwana Zircon and titanite U-Pb dating Hf isotope data Magma source

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The significance of U-Pb zircon ages in zoned plutons:the case of the Flamenco pluton, Coastal Range batholith, northern Chile

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Geoscience Frontiers 2019年第3期10卷 1073-1099页

作者： Natalia Rodríguez Juan Díaz-Alvarado Carlos Fernández Paulina Fuentes Christoph Breitkreuz colombo celso gaeta tassinari Departamento de Geología Universidad de Atacama Departamento de Ciencias de la Tierra Universidad de Huelva Institut für Geologie TU Bergakademie Freiberg High Resolution Geochronological Laboratory University of S?o Paulo

Compositionally zoned plutons, both layered and concentrically arranged, provide granitic exposures where the mechanisms and timing of the magmatic emplacement processes can be studied. The importance of in-situ geochemical differentiation and the magma replenishment rates are revealed by geochemistry and field relations, together with the increasingly accurate U-Pb geochronology, which has promoted the knowledge about the pluton incremental assembly *** Flamenco pluton, located in the Coastal Range of northern Chile, is part of the Upper Triassic to Early Cretaceous Andean intrusives formed in the western active margin of South America, and present a normal zoned structure with mafic magmatic facies(mostly gabbros and Qtz-diorites) close to the contacts with the host metasediments, and tonalites, granodiorites and granites in the inner areas. A combined study of the field relations, geochemistry and zircon geochronology of the magmatic facies was applied to determine the emplacement sequence of the Flamenco pluton, revealing three distinguishable domains separated by metasedimentary septa. The SW area is constituted by mostly homogeneous leucocratic granodiorites that yielded an age of 213 Ma as the best estimation for their emplacement age. Distinctive geochemical characteristics, such as the absence of an Eu anomaly, the depletion in HREE, or the highest Sr, Sr/Y and Ce/Yb values among the granodioritic facies of the pluton,involve lower T and/or higher P conditions at the magmatic source according to experimental *** conditions were established during an early stage of the Andean magmatic arc building that is firstly defined here as Upper Triassic. The NW and E domains of the pluton were sequentially emplaced between 194 Ma and 186 Ma and both the field relations and the detailed geochronological results suggest that the mafic facies intruded latter in the emplacement sequence. To the NW, Qtz-dioritic and gabbroic externally emplaced pulses ga

关键词： Zircon U-Pb geochronology Zoned plutons Andean magmatic arc Sequential emplacement Individual and statistical zircon ages

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Refining the Stratigraphy of the Taghdout Group by Using the U-Pb Geochronology of the Taghdout Sill(Zenaga inlier,Anti-Atlas,Morocco)

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Acta Geologica Sinica(English Edition) 2016年第S1期90卷 1-页

作者： Abdelhak AIT LAHNA colombo celso gaeta tassinari Nasrrddine YOUBI Hassan ADMOU Joao MATA El Hafid BOUOUGRI Latifa CHAIB Richard E.ERNST Ulf SODERLUND Moulay Ahmed BOUMEHDI Mohamed Khalil BENSALAH El Mostapha AARAB Department of Geology Faculty of Sciences-SemlaliaCadi Ayyad University Centro de Pesquisas Geocronológicas(CPGeo) Instituto de Geociencias(IG)Universidade de Sao Paulo-USP Instituto Dom Luiz Faculdade de CiênciasUniversidade de Lisboa Department of Earth Sciences Carleton University Department of Geology Lund University

The Anti-Atlas belt of southern Morocco is situated on the northern edge of the West African craton(WAC).It corresponds to a broad anticlinorium some 800 km long and 200 km wide,trending ENE-WSW,parallel to the

关键词： Pb Zenaga inlier Morocco Refining the Stratigraphy of the Taghdout Group by Using the U-Pb Geochronology of the Taghdout Sill Anti-Atlas

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