Earth Science Frontiers ›› 2022, Vol. 29 ›› Issue (2): 261-280.DOI: 10.13745/j.esf.sf.2022.2.8

Previous Articles     Next Articles

Late Paleozoic crustal composition and growth in West Junggar: Evidence from Sr-Nd-Pb isotopic mapping

XU Shenglin1(), DING Weicui1,*(), CHEN Xuanhua1, LI Tingdong2, HAN Lele1,3, LIU Yong2, MA Feizhou4, WANG Ye1   

  1. 1. SinoProbe Center, Chinese Academy of Geological Sciences, Beijing 100037 China
    2. Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037 China
    3. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083 China
    4. China Geological Survey, Beijing100037 China
  • Received:2021-10-20 Revised:2022-02-15 Online:2022-03-25 Published:2022-03-31
  • Contact: DING Weicui

Abstract:

The West Junggar region has experienced intense Late Paleozoic magmatic activity, where vertical and lateral crustal accretion is significant and crustal growth and evolution is multi-stage. Focusing on Sr-Nd-Pb isotopic mapping, this study found that the West Junggar region has the isotopic characteristics of high positive εNd(t) value of 2.29-8.75, low ( 87Sr/86Sr)i ratio of 0.697397-0.708336, and (206Pb/204Pb)i ratio of 17.4975-19.0352; it has a young crustal model age by calculation. The source area is dominated by Paleozoic new crust, with mantle contribution greater than 50%, and there is almost no old crystalline basement in the deep crust, which is in agreement with regional tectonic geological and geophysical data. The West Junggar region mainly experienced three orogenic stages in the Late Paleozoic: arc-dominated lateral growth in the Middle-Late Carboniferous; post-collision vertical growth in the Late Carboniferous-Early Permian; and vertical growth in the Early Permian-Triassic with crust-mantle mixed source. Regional orogenesis ends in the Early Triassic.

Key words: Late Paleozoic, isotope mapping, crustal composition, crustal growth, orogenic evolution, West Junggar

CLC Number: