Advanced Search
    TIAN Jing, LI Jin-wen, WANG Run-he, LIU Wen, XIANG An-ping, KANG Yong-jian, GUO Zhi-jun, DONG Xu-zhou. Zircon LA-ICP-MS U-Pb ages and geochemical?features of intrusions in Erentaolegai area of Inner Mongolia[J]. GEOLOGY IN CHINA, 2014, 41(4): 1092-1107.
    Citation: TIAN Jing, LI Jin-wen, WANG Run-he, LIU Wen, XIANG An-ping, KANG Yong-jian, GUO Zhi-jun, DONG Xu-zhou. Zircon LA-ICP-MS U-Pb ages and geochemical?features of intrusions in Erentaolegai area of Inner Mongolia[J]. GEOLOGY IN CHINA, 2014, 41(4): 1092-1107.

    Zircon LA-ICP-MS U-Pb ages and geochemical?features of intrusions in Erentaolegai area of Inner Mongolia

    • Abstract: The Erentaolegai silver deposit is a large epithermal silver deposit in Inner Mongolia. In this paper, chronologic and geochemical research were carried out on such intrusions as quartz porphyry, quartz monzonite, biotite syenogranite and fine-grained granite in the ore district. The zircon LA-ICP-MS U-Pb dating?results show that the zircon U-Pb ages of the four intrusion samples are (285.4±1.9) Ma, (294.3±0.6) Ma, (287.0±1.2) Ma and (243.9±1.6) Ma respectively, which shows that the intrusions in the ore district were formed in the two periods of Late Hercynian and Indosinian. The age of the first three samples show that they were formed by magmatic evolution in the Late Hercynian period, and their geochemical features show the depletion of large ion incompatible elements such as Ba, Nb, Sr, Zr and Ti, the remarkable enrichment of K and the depletion of Ta, with weak negative Eu anomalies, and exhibit arc granite characteristics in (Y+Nb)-Rb and Yb-Ta?tectonic environment discrimination diagrams for granitic rock and peraluminous S type granite, which suggests that they were formed in a tectonic environment of syn-collison in combination with the regional tectonic evolution. The zircon U-Pb age of the fine-grained granite is ( 243.9±1.6 ) Ma, suggesting that it was formed by magmatic evolution in the Indosinian period; in addition, its geochemical features show the depletion of large ion incompatible elements such as Ba, Nb, Sr, Ti, Zr and Ti, the remarkable enrichment of K and the loss of Ta, with weak negative Eu anomalies, and has arc granite characteristics in (Y+Nb)-Rb and Yb-Ta?tectonic environment discrimination diagrams for granitic rock and peraluminous S type granite, which implies that it was formed in a tectonic environment of volcanic arc in conjunction with the regional tectonic evolution. According to previous studies, the wall rock of the ore district is Tamulangou volcanic rock formed in the Middle Jurassic, and its 40Ar-39Ar?isochron age is (162.6±0.7) Ma, which shows that there is no genetic relationship between the intrusion and the deposit.
    • loading

    Catalog

      Turn off MathJax
      Article Contents

      /

      DownLoad:  Full-Size Img  PowerPoint
      Return
      Return