Mineral Chemistry,Trace Elements,Isotopic Analysis and Zircon U-Pb Dating in the Hesar Pluton,Northern UDMA,Iran:Implications for Pre-Collisional Magma MixingOACSTPCD
Mineral Chemistry,Trace Elements,Isotopic Analysis and Zircon U-Pb Dating in the Hesar Pluton,Northern UDMA,Iran:Implications for Pre-Collisional Magma Mixing
The Hesar pluton in the northern Urumieh-Dokhtar magmatic arc hosts numerous mafic-microgranular enclaves(MMEs).Whole rock geochemistry,mineral chemistry,zircon U-Pb and Sr-Nd isotopes were measured.It is suggested that the rocks are metaluminous(A/CNK=1.32-1.45),subduction-related I-type calc-alkaline gabbro to diorite with similar mineral assemblages and geochemical signatures.The host rocks yielded an U-Pb crystallization age of 37.3±0.4 Ma for gabbro-diorite.MMEs have relatively low SiO2 contents(52.9-56.6 wt％)and high Mg#(49.8-58.7),probably reflecting a mantle-derived origin.Chondrite-and mantle-normalized trace element patterns are characterized by LREE and LILE enrichment,HREE and HFSE depletion with slight negative Eu anomalies(Eu/Eu*=0.86-1.03).The host rocks yield(87Sr/86Sr)i ratios of 0.70492-0.70510,positive εNd(t)values of+1.55-+2.06 and TDM2 of 707-736 Ma,which is consistent with the associated mafic microgranular enclaves((87Sr/86Sr)i=0.705014,εNd(t)=+1.75,TDM2=729 Ma).All data suggest magma-mixing for enclave and host rock formation,showing a complete equilibration between mixed-mafic and felsic magmas,followed by rapid diffusion.The TDM1(Nd)and TDM2(Nd)model ages and U-Pb dating indicate that the host pluton was produced by partial melting of the lower continental crust and subsequent mixing with injected lithospheric mantle-derived magmas in a pre-collisional setting of Arabian-Eurasian plates.Clinopyroxene composition indicates a crystallization temperature of～1000℃ and a depth of～9 km.
Kazem KAZEMI;Soroush MODABBERI;Parisa GHARIBNEJAD;XIAO Yilin;Fatemeh SARJOUGHIAN;Ali KANANIAN
School of Geology,College of Science,University of Tehran,Tehran,IranResearch Centre for Mineral Resources,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011,China||National Key Laboratory of Ecological Security and Resource Utilization in Arid Areas,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011,ChinaDepartment of Geochemistry and Environmental Sciences,School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,ChinaDepartment of Earth and Sciences,Faculty of Sciences,University of Kurdistan,Sanandaj,Iran||Department of Science Education,Farhangian University,Tehran,Iran
enclavemagma mixingzircon U-Pb datingUrumieh-Dokhtar magmatic arc
《地质学报（英文版）》 2024 (003)
657-678 / 22
This work has been supported by the Iran National Science Foundation(INSF)(Grant No.98012578)and projects from the National Natural Science Foundation of China(Grant Nos.41473033,41673031).ICP-MS,U-Pb dating,Sr-Nd isotopic analyses and XRF analysis were carried out at the University of Science and Technology of China and the ALS Chemex(Guangzhou)Co.,Ltd.,respectively.The electron probe microanalyses(EPMA)of minerals were carried out at the Hefei University of Technology,China.We acknowledge the skillful assistance of Ms.Wang Juan during the EPMA analysis.We would like to thank Dr.Hou Zhenhui,Dr.Wang Yangyang,and Dr.Tong Fengtai for their technical assistance during the analysis at USTC.
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