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      https://www.ias.ac.in/article/fulltext/jess/122/03/0809-0830

    • Keywords

       

      A-type; I-type; continental arc; rifting; Lengshuikeng; southeast China.

    • Abstract

       

      SE China is well known for its Mesozoic large-scale granitoid plutons and associated ore deposits. Here, zircon U–Pb geochronological and geochemical data have been used to better constrain the petrogenesis of the igneous rocks associated with porphyry Ag–Pb–Zn deposits in the Lengshuikeng ore district, SE China. The Lengshuikeng rhyolitic tuff, granite porphyry and syenogranite yielded zircon U–Pb ages of 161, 155 and 138 Ma, respectively. The Lengshuikeng granite porphyries belong to calc-alkaline series and show fractionated I-type affinities. The rhyolitic tuffs show almost similar characteristics as the granite porphyries. The engshuikeng syenogranites are all alkali-rich and show A-type affinities. The syenogranites have high contents of high field strength elements such as Nb, Ta, Zr, Hf; with Zr + Nb + Ce + Y contents of < 350 ppm. Chondrite-normalized REE patterns show relative enrichment of LREEs and strong negative Eu anomalies. The Lengshuikeng granite porphyries, syenogranites and tuffs were probably derived from partial melting of underlying Proterozoic metasedimentary rocks with minor addition of mantle-derived magmas, accompanied by fractional crystallization. Detailed petrologic and geochemical data for the Jurassic igneous rocks from the Lengshuikeng ore district imply that during the Late Jurassic, SE China on the southeast of the Shi-Hang zone was a continental arc associated with the subduction of the Palaeo-Pacific plate and that since the beginning of the Early Cretaceous an intra-arc rift has been formed along the Shi-Hang zone.

    • Author Affiliations

       

      Changming Wang1 Da Zhang2 Ganguo Wu1 Yigan Xu1 Emmanuel John M Carranza3 Yaoyao Zhang1 Huaikun Li4 Jianzhen Geng4

      1. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China.
      2. No. 912 Geological Surveying Team, Bureau of Geology and Mineral Exploration and Development, Yingtan 334000, China.
      3. Geo-Information Science and Earth Observation (ITC), University of Twente, Enschede, The Netherlands.
      4. Tianjin Center of China Geological Survey, Tianjin 300170, China.
    • Dates

       
  • Journal of Earth System Science | News

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