Constraints on timing and origin of the Dayinjian intrusion and associated molybdenum mineralization, western Dabie orogen, central China

Hongchao Li, Zhaowen Xu*, Xiancai Lu, Wei Chen, Wenjun Qu, Bin Fu, Xiaonan Yang, Jie Yang, Jinquan Chen

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    26 Citations (Scopus)

    Abstract

    The Early Cretaceous geology of the western Dabie Mountains is characterized by widespread granitoid pluton emplacement and associated Mo mineralization. We report LA-ICP-MS zircon U-Pb and molybdenite Re-Os dating, whole-rock chemical and Sr-Nd-Pb isotopic compositions, as well as in situ zircon Hf isotopic geochemistry, for the Dayinjian granite in the region to better constrain its petrogenesis. U-Pb zircon dating yielded a weighted average age of 124.9 ± 1.3 Ma (mean square weighted deviation (MSWD)=0.51, 2σ). Re-Os isotopic dating of molybdenite from the Dayinjian ore deposit yielded an isochron age of 125.07 ± 0.87 Ma (MSWD=0.015), and a weighted average age of 124.54 ± 0.67 Ma (MSWD=0.34). The petrogenesis and metallogenesis of the Dayinjian complex are related to the onset of widespread post-orogenic magmatism and local mineralization in the western Dabie orogen. Whole-rock geochemistry indicates that the Dayinjian granite is a highly fractionated calc-alkaline granite possessing relatively high ( 87Sr/ 86Sr)i ratios (0.706379-0.707173), low Nd(T) values (-15.62 to-15.17), high Nd model ages (=2.15-2.18 Ga), and low radiogenic Pb isotopes (( 206Pb/ 204Pb) i =16.793-16.979, ( 207Pb/ 204Pb) i =15.379-15.487, and ( 208Pb/ 204Pb) i =37.559-37.976). Its magmatic zircons also exhibit very low Hf(T) values (-24.80 to-17.80) and old Hf model ages (=2.31-2.75 Ga). These isotopic compositions suggest that the Dayinjian granite is probably of anatectic origin and was derived from the lower crust at a depth <35 km, similar to the western Dabie gneiss. Ore-bearing fluids were produced during late-stage magmatic hydrothermal activity and were thereafter influenced by the circulation of meteoric water that concentrated molybdenite in open-space areas.

    Original languageEnglish
    Pages (from-to)1579-1596
    Number of pages18
    JournalInternational Geology Review
    Volume54
    Issue number13
    DOIs
    Publication statusPublished - 10 Oct 2012

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