Zircon U- Pb Dating and Hf Isotopic Compositions of the Anjishan Granodiorite Porphyry and Weigang Granodiorite in the Ningzhen Ore Cluster Area and Their Geological Implications
DOI:
Author:
Affiliation:

Development Research Center of China Geological Survey,Institute of Mineral Resources, Chinese Academy of Geological Sciences,Development and Research Center, China Geological Survey,Development and Research Center, China Geological Survey,Development and Research Center, China Geological Survey,Development and Research Center, China Geological Survey,Aston University,Development and Research Center, China Geological Survey,Development and Research Center, China Geological Survey

Clc Number:

Fund Project:

  • Article
  • |
  • Figures
  • |
  • Metrics
  • |
  • Reference
  • |
  • Related
  • |
  • Cited by
  • |
  • Materials
  • |
  • Comments
    Abstract:

    Ningzhen ore cluster area, located in the eastern section of the Middle- Lower Yangtze River Reaches metallogenic belt, hosts a large amount of intermediate- felsic intrusive rocks related to copper and iron deposits. For example, the Anjishan granodiorite porphyry and Weigang granodioritethe in the study area are closely related to copper and iron deposits such as Anjishan copper deposit, Funiushan iron deposit. Many petrological studies have been conducted in the Ningzhen ore cluster area, but study on source characteristics of these granitic rocks is relatively poor. In this study, we conducted LA- ICP- MS zircon U- Pb dating and zircon Hf isotope analyses for samples from the Anjishan complex and Weigang complex, to determine diagenetic ages and discuss characteristics of the magmatic source and their relation with mineralization. Our zircon U- Pb dating yields diagenetic ages of 108.9~110.9 Ma and 107.3~109.6 Ma respectively for Anjishan granodiorite- porphyry and Weigang granodiorite, indicating the diagenetic age of late Mesozoic magmatic rocks in the Ningzhen ore cluster area should be 110~100 Ma, about 20 Ma later than that in other area of the Middle- Lower Yangtze River Reaches metallogenic belt. Hf isotope analyses show that the zircon εHf(t) value of the Weigang granodiorite ranges from -47.4 to -16.9 with a mean value -24.9, and the two- stage TDM2 Hf age ranges from 2.24 to 4.14 Ga, with an average of 2.73 Ga, suggesting that the Weigang granodiorite resulted from partial melting of the lower crust during the Mesoarchean to Paleoproterozoic. While zircon εHf(t) value of the Anjishan granodiorite porphyry ranges from -16.8 to -8.9 with a mean value of -12.4 and the two- stage TDM2 Hf age ranges from 1.74 to 2.23 Ga with a mean value of 1.96 Ga, suggesting that the Anjishan granodiorite porphyry was probably mixing of the materials from mantle and lower crust. This study, combined with previous results, concludes that the complex related to skarn- type iron deposit contains more crustal material than the complex related to skarn- type copper deposit. The ratio of material contents between crust and mantle in the source area of magma is likely an important factor controlling the mineralization of copper and iron in the MiddleLower Yangtze River Reaches metallogenic belt.

    Reference
    Related
    Cited by
Get Citation

ZHANG Mingchao, CHEN Renyi, YE Tianzhu, YAO Lei, LI Jingchao, LI Yongsheng, HE Xi, SUN Hairui, LIU Siyu.2018. Zircon U- Pb Dating and Hf Isotopic Compositions of the Anjishan Granodiorite Porphyry and Weigang Granodiorite in the Ningzhen Ore Cluster Area and Their Geological Implications[J]. Acta Geologica Sinica,92(11):2248-2268

Copy
Share
Article Metrics
  • Abstract:
  • PDF:
  • HTML:
  • Cited by:
History
  • Received:December 16,2017
  • Revised:September 12,2018
  • Adopted:April 11,2018
  • Online: November 15,2018
  • Published: