Welcome to visit Geoscience!

Geoscience ›› 2019, Vol. 33 ›› Issue (01): 98-111.DOI: 10.19657/j.geoscience.1000-8527.2019.01.10

• Petrology • Previous Articles     Next Articles

Geochronology and Geochemistry of Paleoproterozoic Intrusive Rocks in Western Huanren Area, Eastern Liaoning Province

LUO Niangang1(), WANG Binna2, LIU Xiancheng3, HONG Xiuwei1, YU Botao3, LI Qing3   

  1. 1. Geological Survey Institute Co.Ltd.of Liaoning Province,Shenyang,Liaoning 110031,China
    2. Liaoning Institute Co.Ltd.of Mineral Exploration,Shenyang,Liaoning 110031,China
    3. No.241 Team Co.Ltd., Liaoning Bureau of Nuclear Geology,Fengcheng,Liaoning 118100,China
  • Received:2018-05-23 Revised:2018-12-20 Online:2019-02-26 Published:2019-02-28

Abstract:

Paleoproterozoic intrusive rocks are widespread in the Eastern Liaoning Province (ELP), which is located in the eastern North China Craton (NCC). This paper reported the petrography, geochemistry and geochronology of the Beigou, Zhengcha and Liulinzi plutons in the Kaiyuan area of the eastern part of the northern NCC margin. We discussed the formation age, petrogenesis and tectonic environment of these plutons. Zircon U-Pb dating shows that both the Liulinzi (2,490±8 Ma) and Beigou (2,457±11 Ma) plutons were formed in the Early Paleoproterozoic. The Beigou intrusive rocks have higher SiO2 and K2O contents, and are enriched in large ion lithophile elements (LILEs, e.g., Rb, K, U and Th) but depleted in high field strength elements (HFSEs, e.g., P, Nb and Ti), with Nb/Ta=5.75 and Rb/Nb=4.21. These features indicate that the Beigou pluton is metaluminous calc-alkaline I-type granite, which was likely originated from the partial melting of lower crust. The Zhengcha pluton samples have higher SiO2 and K2O contents. They are also enriched in LILEs and depleted in HFSEs, with Nb/Ta=16.06 and Rb/Nb=4.81. These features indicate that the Zhengcha pluton is metaluminous calc-alkaline A-type granite, which was most likely originated from the partial melting of lower crust with minor mantle-derived input. The Liulinzi meta-gabbro is sub-alkaline, enriched in LILEs and depleted in HFSEs, indicating that the magma may have derived from the depleted mantle with crustal contamination in an intracontinental extension setting. Combined with previous studies, magmatic rocks of the study area may have formed under a compressional to extensional tectonic transition regime after the collision between the Eastern block and the Western block of the NCC.

Key words: eastern Liaoning Province(ELP), Paleoproterozoic, intrusive rock, zircon SHRIMP U-Pb dating, geochemistry, tectonic setting

CLC Number: