Welcome to visit Geoscience!

Geoscience ›› 2023, Vol. 37 ›› Issue (03): 586-598.DOI: 10.19657/j.geoscience.1000-8527.2021.149

• Petrology and Petrogeochemistry • Previous Articles     Next Articles

Geochronology, Geochemistry and Geological Significance of Tuanbaoshan Metamorphic Rocks in Haiyan, Qinghai Province

WANG Xiangwei1,2(), ZHANG Baotao3(), YANG Haoqiang3, HAN Jinguo3   

  1. 1. Shandong Zhengyuan Geological Resources Exploration Co.,Ltd., Jinan,Shandong 250101, China
    2. Institute of mineral resources, China Metallurgical Geology Bureau, Beijing 100131, China
    3. Geological Exploration Institute of Shandong Zhengyuan, China Metallurgical Geology Bureau, Jinan, Shandong 250013, China
  • Received:2021-03-06 Revised:2023-03-29 Online:2023-06-10 Published:2023-07-20

Abstract:

The Tuanbaoshan metamorphic rocks (Hualong Group) are widely distributed in eastern South Qilian (Haiyan County, Qinghai Province). To deepen our understanding on the local metamorphic rocks and their geological significance, analyses of petrography, geochronology and geochemistry were conducted on the least-altered samples. The obtained weighted average ages ((2,047±30) Ma and (755±13) Ma) indicate that the formation age is Late Proterozoic. The average chemical content of the rock: SiO2 accounts for 62%, FeO accounts for 4.79%, Fe2O3 accounts for 6.44%, MgO accounts for 3.46%, and the average total amount of rare earth elements is 476×10-6. The rocks right-inclining chondrite-normalized REE and flat HREE patterns, weak Eu anomalies and LREE enrichment. The metamorphic rocks are rich in high field strength elements (HFSEs, e.g., Th, U, Ce, Zr, and Hf), but depleted in lithophile elements (e.g., Ba, P, and Ti). Comprehensive geochronological and geochemical characteristics suggest that protoliths of the local metamorphic rocks are mainly felsic sandy mudstone, and the protolithic formation environment may have been continental arc associated with the Rodina supercontinent breakup.

Key words: geochronology, geochemistry, protolith characteristic, metamorphic rock, Tuanbaoshan

CLC Number: