首页|Geochemistry,zircon U-Pb geochronology,and Hf isotopes of S-type granite in the Baoshan block,constraints on the age and evolution of the Proto-Tethys

Geochemistry,zircon U-Pb geochronology,and Hf isotopes of S-type granite in the Baoshan block,constraints on the age and evolution of the Proto-Tethys

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Geochemistry,zircon U-Pb geochronology,and Hf isotope data for the Early Paleozoic granites in the Baoshan Block reveal the Early Paleozoic tectonic evolu-tion of the Proto-Tethys.The samples are high-K,calc-alkaline,strongly peraluminous rocks with A/CNK values of 1.37-1.46,are enriched in SiO2,K2O,and Rb,and are depleted in Nb,P,Ti,Eu,and heavy rare earth elements,which indicates the crystallization fractionation of the granitic magma.Zircon U-Pb dating indicates that they formed in ca.480 Ma.The Nansa granites have εHf(t)val-ues ranging from-16.04 to 4.36 with corresponding TCDM ages of 2.10-0.81 Ga,which suggests the magmas derived from the partial melting of ancient metasedimen-tary with minor involvement of mantle-derived compo-nents.A synthesis of data for the Early Paleozoic igneous rocks in the Baoshan block and adjacent(Tengchong,Qiangtang,Sibumasu,Himalaya,etc.)blocks indicates that these blocks were all aligned along the proto-Tethyan margin of East Gondwana in the Early Paleozoic.The Early Paleozoic S-type granites from Nansa were generated in a high-temperature and low-pressure(HTLP)exten-sional tectonic setting,which resulted from Andean-type orogeny instead of the final assembly of Gondwana or crustal extension in a non-arc environment.In certain places,an expanding environment may exist in opposition to the tectonic backdrop of the lithosphere's thickening and shortening,leading the crust to melt and decompress,mantle-derived materials to mix,and a small quantity of peraluminous granite to emerge.

Baoshan blockEarly PaleozoicGraniteGeochemistryZirconGeochronologyHf isotope

Jianjun Zhang、Chuanlong Mou、Chendong Liu、Yong Zhang、Ting Chen、Hualiang Li

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Institute of Geological Survey,East China University of Technology,Nanchang 330013,China

School of Earth Sciences,East China University of Technology,Nanchang 330013,China

Chengdu Geological Survey Center,Chengdu 610081,China

School of Water Resources & Environmental Engineering,East China University of Technology,Nanchang 330013,China

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国家自然科学基金国家自然科学基金国家自然科学基金

2019M653840XB4197204342062006

2024

地球化学学报(英文版)
中国科学院地球化学研究所

地球化学学报(英文版)

EI
影响因子:0.33
ISSN:2096-0956
年,卷(期):2024.(1)
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