Detrital zircon U-Pb geochronology and geochemistry of the Riachuelos and Palma Sola beach sediments,Veracruz State,Gulf of Mexico:a new insight on palaeoenvironment  

作　　者：John S.Armstrong-Altrin 

机构地区：[1]Unidad de Procesos Oceánicos y Costeros,Instituto de Ciencias del Mar y Limnología,Universidad Nacional Autónoma de México,Ciudad Universitaria,Ciudad de México 04510,México

出　　处：《Journal of Palaeogeography》2020年第4期495-521,共27页古地理学报（英文版）

基　　金：This study was supported by the Consejo Nacional de Ciencia y Tecnologfa(CONACyT)(Project No.Al-S-21287);Direcci6n General de Asuntos del Personal Academico(DGAPA)—Programa de Apoyoa Proyectos de Investigacione Innovacion Tecnologia(PAPIIT)(Project No.IN 107020);Instituto de Ciencias del Mary Limnologia Institutional Fund(Project No.616).

摘　　要：Zircons are abundant in the beach sediments.In this study,surface microtexture,mineralogy,bulk sediment geochemistry,trace element composition and U−Pb isotopic geochronology of detrital zircons collected from the Riachuelos and Palma Sola beach areas,southwestern Gulf of Mexico were performed to infer the sediment provenance and palaeoenvironment.The zircon microtexture was categorized as mechanically-and/or chemically-induced features.The weathering index values for the Riachuelos(~72−77)and Palma Sola(~71−74)beach sediments indicated moderate weathering of both of the two source areas.The major and trace element data of bulk sediments suggested passive margin settings for the two areas.The trace elemental ratios and chondrite-normalized rare earth element(REE)patterns of bulk sediments revealed that the sediments were likely sourced by felsic and intermediate igneous rocks.And the zircon Th/U ratios(mostly more than 0.2)and zircon REE patterns(with negative Eu and positive Ce anomalies)suggested a magmatic origin for both of the beach sediments from these two areas.Two distinct zircon age peaks respectively belonging to the Paleozoic and the Cenozoic were identified both in the Riachuelos and Palma Sola beach sediments.Zircon geochronology comparison research between the Riachuelos−Palma Sola beach sediments and potential source areas in SW Gulf of Mexico revealed that the source terrane supplied the Paleozoic zircons of this study was identified as the Mesa Central Province(MCP),and the Cenozoic zircons were transported from the nearby Eastern Alkaline Province(EAP).Moreover,although the Precambrian zircons were very few in the studied sediments,their geochronology and geochemistry results still could infer that they were contributed by the source terranes of Grenvillian igneous suites in the Oaxaca and the Chiapas Massif Complexes.

关 键 词：Detrital zircon Beach sediment U-Pb dating Zircon grain morphology MICROTEXTURE Mineralogy Geochemistry Geochronology Gulf of Mexico 

分 类 号：P597.3[天文地球—地球化学]