Geochemical characteristics and genesis of biotites from Late Mesozoic granites in the Cuihuashan-Kuyu area,North Qinling
In order to discuss the complex and diverse genetic mechanism of Late Mesozoic magmas in the North Qinling orogenic belt,this paper takes the Late Mesozoic monzogranite in Cuihuashan,Dayu and Kuyu areas in the middle part of the North Qinling as the research object,and uses the electron probe technology to make geochemical analysis of the biotite in the monzogranite.The results show that the main body of biotite in the samples belongs to magnesian biotite,and its genetic type is primary biotite.The calculated mineral chemistry data show that the average crystallization pressure of biotite in Cuihuashan,Dayu and Kuyu monzogranite samples is 205,202 and 211 MPa,the corresponding crys-tallization depths is 7.8,7.6 and 8.0 km,and the average crystallization temperature is 711,653 and 657℃,respectively.The mean values of oxygen fugacity were-16.45,-18.40 and-18.27,respec-tively.Based on the above results,it is revealed that the monzogranites in the study area are mainly derived from the crust with a small amount of mantle-derived materials added,and the Cuihuashan,Dayu and Kuyu monzogranites have I-type granitic affinities and belong to the orogenic calc-alkaline granite series.
国家科技期刊平台
NSTL
万方数据
