自然界的岩石中存在着放射性元素,这些元素在衰变过程中会释放出热能,放射性生热是岩石圈内热的主要来源之一。山东省陈庄潜凸起区作为一个干热岩勘探研究区域,在干热岩调查研究方面取得了一些基础性资料。本文对该区大地热流及地温场进行分析的基础上,利用Rybach 生热率公式计算了钻孔岩石的放射性生热率,从GRY1 孔的生热率与深度的关系来看,1650 m 以上,生热率整体数值较大,且变幅较大,在埋深1430~1645 m 生热率达到4.72~6.78 μW/m3,该区间主要由含黑云母二长花岗岩及绿泥石化二长花岗岩组成。1645~2500 m 区间主要由花岗岩及含黑云母闪长岩、辉长岩组成,生热率有所降低。整体来说,花岗岩中生热率变化较小,一般在2.0~2.5 μW/m3;而含黑云母二长花岗岩及弱绿泥石化二长花岗岩生热率较高,且变化较大。
Radioactive elements exist in rock in the nature, which will release energy in the decaying process. Radioactive heat production is one of the main sources for lithospheric heat. Some basic information has been obtained about Chenzhuang uplift, Shandong Province as a hot dry rock exploration and study site. This paper calculates the radiogenic heat ratio of the rock core using Rybach heat generation rate formula, on the basis of analysis of terrestrial heat flow and geothermal field. The vertical distribution of heat generation rate at GRY1 borehole shows that the heat generation rate was larger with greater variation above 1650 m, and reached 4.72-6.78 μW/m3 at depth of 1430-1645 m, where biotite adamellite and chloritized adamellite mainly exist. At the interval of 1645-2500 m, where the rock is mainly composed of granite, biotite bearing diorite, and gabbro, the heat generation rate decreased. Overall, the heat generation rate of granite changed slightly, which was about 2.0-2.5 μW/m3, while that of biotite adamellite and slightly chloritized adamellite was higher with larger variation.
[1] 吴耀, 金振民, 欧新功, 等. 中国大陆科学钻探(CCSD)主孔地区岩石圈 热结构[J]. 岩石学报, 2002, 21(2): 18-22. Wu Yao, Jin Zhenmin, Ou Xingong, et al. Lithospheric thermal structure beneath the area of the Chinese Continental Scientific Drilling Site (CCSD)[J]. Acta Petrologica Sinica, 2002, 21(2): 18-22.
[2] AlbaredeF.1975Theheatflow-heatgenerationrelationship:An interaction model of fluids with cooling intrusions[J]. Earth and Planetary Science Letters, 1975, 27: 73-78.
[3] 迟清华, 嫣明才. 华北地台岩石放射性元素与现代大陆岩石圈热结构 和温度分布[J]. 地球物理学报, 1998, 41(1): 32-34. Chi Qinghua, Yan Mingcai. The north China platform of radioactive elements and modern rock lithospheric thermal structure and temperature distribution[J]. Journal of Geophysics, 1998, 41(1): 32-34.
[4] Blackwell D D. The thermal structure of the continental crust[C]//Heacock J G. The structure and physical properties of the Earth's crust. American Geophysical Union Geophysical Monograph, 1971, 14: 169-184.
[5] Kremenetsky A A, Milanovsky S Y U, Ovchinnikov L N. A heat generation model for continental crust based on deep drilling in the Baltic shield[J]. Tectonophysics, 1989, 159: 231-246.
[6] 何丽娟, 胡圣标, 汪集旸. 中国东部大陆地区岩石圈热结构特征[J]. 自 然科学进展, 2011, 11(9): 966-969. He Lijuan, Hu Shengbiao, Wang Jiyang. Lithospheric thermal structure characteristics of eastern China[J]. Progress in Natural Science, 2011, 11(9): 966-969.
[7] 曾令森, 刘福来, 张泽明, 等. 中国大陆科学钻探工程主孔100～2000 m放射性产热元素的垂向分布特征及其成因[J]. 中国地质, 2005, 32 (2): 20-23. Zeng Lingsen, Liu Fulai, Zhang Zeming, et al. Vertical distribution characteristics and origin of radiogenic heat-producing elements (HPE) in the first 2000m of the main hole of the CCSD project[J]. Geology in China, 2005, 32(2): 20-23.
[8] 黄少鹏. 全球大地热流-岩石生热率关系综合分析[J]. 地球物理学报, 1998, 41(增1): 26-31. Huang Shaopeng. Global heat flow-rock heat generation comprehensive analysis[J]. Journal of Geophysics, 1998, 41(Suppl 1): 26-31.
[9] 何丽娟. 流变边界层及其对华北克拉通热/地震岩石圈底界差异的意 义[J]. 地球物理学报, 2014, 57(1): 53-61. He Lijuan. The Rheological boundary layer and its implications for the difference between the thermal and seismic lithospheric bases of the North China Craton[J]. Journal of Geophysics, 2014, 57(1): 53-61.
[10] 何丽娟, 胡圣标, 杨文采, 等. 中国大陆科学钻探主孔揭示的大陆地 壳生热模型[J]. 岩石学报, 2006, 22(11): 2808-2814. He Lijuan, Hu Shengbiao, Yang Wencai, et al. Heating generation model for the continental crust based on the main hole of the Chinese contineental scientific drilling project[J]. Acta Petrologica Sinica, 2006, 22(11): 2808-2814.
[11] Arevalo Jr R, McDonough W F, Luong M. The K/U ratio of the silicate Earth: Insights into mantle composition, structure and thermal evolution[J]. Earth and Planetary Science Letters, 2009, 278: 361-369.
[12] Birch F. Heat from radioactivity[M]// Faul H. Nuclear Geology. New York: John Wiley & Sons, 1954: 148-174.
[13] Rybach L. Radioactive heat production in rocks and its relation to other petrophysical parameters[J]. Pure and Applied Geophysics, 1976, 114: 309-318.
[14] Wollenberg H A, Smith A R. Radiogenic heat production of crustal rocks: An assessment based on geochemical data[J]. Geophysical Research Letters, 1987, 14: 295-298.
[15] 张邦桐, 凌洪飞, 陈培荣, 等. 岩石古放射性生热率的校正及其地球 化学意义[J]. 矿物岩石地球化学通报, 2010, 29(2): 17-21. Zhang Bangtong, Ling Hongfei, Chen Peirong, et al. Correction to the paleoradiogenic heat production rate of rocks and its geochemical significance[J]. Bulletin of Mineralogy, Petrology and Ggeochemistry, 2010, 29(2): 17-21.
[16] 赵平, 汪集旸, 汪缉安, 等. 热流和岩石生热率关系的研究[J]. 地质科 学, 1996, 31(3): 297-307. Zhao Ping, Wang Jiyang, Wang Ji'an, et al. Study on the relationship between heat flow and heat production[J]. Chinese Journal of Geology, 1996, 31(3): 297-307.
