浙江燕山期花岗岩类放射性生热率特征研究

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

浙江省位于中国东部沿海高热流地热异常区,燕山期岩浆侵入活动强烈,高放射性产热型干热岩资源潜力巨大。燕山期花岗岩类生热元素分布规律研究表明:石英正长岩类、二长花岗岩、正长花岗岩和花岗岩的K_2O含量相近,花岗岩的U、Th含量最高。岩体放射性生热率计算结果表明:不同花岗岩类放射性生热率相差较大。石英正长岩类生热率相对最低,变化范围相对较窄,平均值为2. 14μW/m^3;正长花岗岩生热率变化范围相对较宽,平均值为3. 31μW/m^3;花岗岩生热率相对最高,平均值为5. 41μW/m^3。参照高放射性产热型干热岩开发的地热地质学标准,初步判定浙西北泗岭、九华山、河桥、儒洪和学川(顺溪)及浙东南小将等岩体,具有较好的干热岩资源勘查前景。

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 K 2O 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 2.14μW/m^3;syenite has a wide range of heat generation with an average of 3.31μW/m^3;and granite has the highest heat generation with an average of 5.41μW/m^3.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.