川西塔公松林口岩体 LA-ICP-MS 锆石 U-Pb 年龄与地球 化学特征.

BACKGROUND: The Songlinkou pluton is located in the eastern margin of the Songpan - Ganzi orogenic belt, which is adjacent to the pegmatite - type lithium deposit of Jiajika. OBJECTIVES: In order to explore the similarities and differences between Songlinkou pluton and Jiajika mineralizing intrusive rocks, and to study geological conditions of mineralization and material source of the pluton. METHODS: Geochronology research by LA - ICP - MS zircon U - Pb dating, Lu - Hf isotope study of zircon by MC - ICP MS, the rare earth and trace elements were determined by ICP - MS. RESULTS: The Songlinkou pluton is rich in diorite enclaves, which contents of SiO2 are 56. 56% -68. 99%, total alkali are 3. 78% -6. 82%, K2 O/Na2 O is 1. 02 -1. 93, Rittmann indexes are 1. 01 -1. 93. The rock has relative high Ml values( Ml =46. 73 -61. 27), which has the characteristics of enrichment of light rare earths, the LREE/HREE = 2. 67 - 8. 31, LaN/YbN = 2. 11 - 9. 74, and all samples have strong Eu negative anomaly. It is rich in LILE, but Ta, Nb, P, Ti are depleted of the pluton. The zircon U - Pb results of the granodiorite and monzogranite are 212. 6 ± 1. 0Ma ( MSWD = 0. 55) and 222. 4 ± 1. 1 Ma ( MSWD = 0. 39). The eHf( t) of zircon Lu - Hf isotope of monzogranite is -9. 09 to -6. 86,and TcDM. is between 1524. 9 Ma and 1666 Ma. CONCLUSIONS: The Songliankou pluton belongs to high potassium Cale - alkaline I - type granite, which is the partial melting of the middle Proterozoic Yangtze craton basement and mixed with enrichment of upper mantle material. The Jiajika S - type granite is formed by partial melting of the upper crust, and is different from Songliankou pluton in terms of material sources, magmatic evolution and mineralization tectonic conditions. That may be the main reason why the Songlinkou pluton does not have lithium rare metal mineralization [ABSTRACT FROM AUTHOR]