Determination of Yanshanian Granite and its Geological Significance in the Taka Dome, Western Sichuan

Abstract

This is an article in the field of earth sciences. Jiulong area is the most concentrated area of Yanshanian granite found in western Sichuan, including Tiechanghe, Qiaopengzi-Landiao and Xinhuoshangranite. In this paper, LA-ICP-MS zircon U-Pb dating were carried out to determine the formation age of the granite， and its temporal-spatial relationship with the surrounding granites, providing a basis for the comparative study of Liwu copper deposit in the southern margin of Songpan-Ganzi block. The results show thatthe diagenetic age of Huajiaoping granite is (163.1±1.4) Ma, andit underwent magmatic or tectonic thermal events at (146±3) Ma, which is consistent withthe geological events ofTiechanghe, Xinhuoshan and Luomogranite. The magma temperature of Huajiaoping granite is 592～727 ℃ (average temperature 648 ℃), which is significantly lower than that of Qiaopengzi granite (766～804 ℃). Combined with the regional geological background, about 170 ～ 140 Ma, the lithosphere in the southern margin of Songpan Ganzi block is in the extension stage. The granite magma activity dominated in the early stage (163 Ma) by Huajiaoping granite, and in the late stage (146 Ma) by magmatism or tectonic thermal events. This discovery enriched the Yanshannian granitic magmatic thermal events in Jiulong area.

Keywords

• earth sciences
• western sichuan
• jiulong
• huajiaoping
• granite
• zircon