Characteristic study of radioactive heat generation of the Yanshanian Granitoids in Zhejiang

Zhejiang is located in the high heat flow geothermal anomaly area along the eastern coast of China. The Yanshanian magmatic activities were intensive, thus forming high resource potential of hot dry rock(HDR)with high radioactive heat generation. The study of the distribution law of heat generating elements in the main Yanshanian granitoids shows that quartz syenite, monzonitic granite, syenogranite, granite contain similar K₂O contents, and granite contains highest U and Th concentration. The calculation results for radioactive heat generation of rocks indicate that the radioactive heat generation rate varies greatly with types of granitoids. Quartz syenite has relatively low heat generation with a narrow change range and an average of 2.14 μW/m³; syenite has a wide range of heat generation with an average of 3.31 μW/m³; and granite has the highest heat generation with an average of 5.41 μW/m³. According to the geothermal standard of high radioactive heat production HDR, it can be determined preliminarily that Siling, Jiuhuashan, Heqiao, Ruhong and Xuechuan(Shunxi)in northwestern Zhejiang and Xiaojiang in southeastern Zhejiang are of good prospecting outlook for hot dry rocks exploration.