Earth Science Frontiers ›› 2021, Vol. 28 ›› Issue (5): 380-412.DOI: 10.13745/j.esf.sf.2020.12.9

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Geochronology, petrogenesis and tectonic implications of the Qiaodian granite porphyry from the western Dabie Orogenic Belt, Central China

HUANG Haiyong1,2,3(), XU Yang1,2,4,*(), YIN Xuwei1,3, YANG Kunguang4, LIU Yu4   

  1. 1. Wuhan Center, China Geological Survey, Wuhan 430205, China
    2. State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
    3. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China
    4. Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, China University of Geosciences(Wuhan),Wuhan 430074, China
  • Received:2020-04-10 Revised:2020-09-01 Online:2021-09-25 Published:2021-10-30
  • Contact: XU Yang


The ca. 145-120 Ma granitoids were regarded as important products of the thickened, delaminated partial melting Cretaceous crust beneath the Dabie Orogenic Belt. Our newly identified Qiaodian granite porphyry in the western Dabie Orogenic Belt can provide new constraints on the progression of lithospheric thinning and the transformation of tectonic regime to an extensional setting. SIMS and LA-ICP-MS zircon U-Pb dating suggests the Qiaodian granite porphyry was emplaced at 129 Ma. It has a negative zircon εHf(t) value (between -24.5 and -14.7) with a two-stage model age of 2.4-1.9 Ga, and is characterized by coarse-grained feldspar phenocrysts. It has variable SiO2 contents (63.07%-73.22%) and A/CNK values (0.87-1.73), with high K2O(4.51%-5.47%) and low MgO(0.42%-1.82%) contents, suggesting high-K calc-alkaline granite affinity. It exhibits LREE-enriched rare earth elemental distribution patterns ((La/Yb)N=29.6-34.2) with negative Eu anomalies ((Eu/Eu *)=0.77-0.92). The primitive mantle-normalized trace element patterns show enrichments of Rb, Ba and Pb and depletions of Nb, Ta and Ti. Compared with typical adakites, the Qiaodian granite porphyry has variable Sr((78-724)×10-6) and relatively high Y((11.8-14.8)×10-6) and Yb((1.09-1.37)×10-6) contents, yielding a low Sr/Y ratio (6.7-55.5). These geochemical features, together with Paleoproterozoic residual zircon and two-stage Hf model ages, indicate the Qiaodian granite porphyry mainly derived from partial melting of Paleoproterozoic mafic materials at medium to low pressures. On the basis of our new results and previously published data, we consider the tectonic collapse and transformation of the western Dabie Orogenic Belt probably occurred around 130 Ma.

Key words: zircon U-Pb-Hf isotopes, high-K calc-alkaline granite, Early Cretaceous, western Dabie Orogenic Belt

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