摘要
中国已发现的150℃以上的高温地热资源及其成因机制研究集中分布在地中海-喜马拉雅地热带的西藏南部和云南、四川西部,环太平洋地热带的中国台湾省。近年来,华北中东部高温地热资源探测取得突破:2019年在河北省马头营3965 m深钻获了151℃的高温花岗岩干热岩体,2020年在山西省天镇县1586 m深钻获167℃的高温片麻岩裂隙热储地热流体,2023年在山东省东营市桩西地区4283 m深钻获167.5℃的高温碳酸盐岩岩溶热储;因此,亟需对华北中东部高温地热资源成因机制进行系统研究。本文以上述高温地热田为例,分析华北克拉通破坏、壳幔热物质上涌对地壳浅部高温热异常作用的动力学过程,结合地球物理、地球化学和钻探成果,阐明深部地球动力地质作用对地球浅部高温地温场的塑造和高温热异常制约机制,揭示深部高温热源机制及其上涌通道,形成深部高温热源及其上涌通道和热能聚集构造部位识别技术;阐释典型地段高温地热资源成因机制及其对华北中东部高温地热探测的示范意义。(1)在印欧板块碰撞的远场效应和西太平洋板块俯冲回撤作用下,华北克拉通破坏造成岩石圈减薄、软流圈上涌和热侵蚀、伸展断陷盆地及深大走滑断裂发育等深部地球动力作用,是幔源热物质上涌至地壳浅部的主要驱动力。(2)高导低速体、地球化学证据和高温地热资源分布形成了良好的对应关系,认为幔源热物质向上侵入引起了浅层热异常,为高温地热形成提供了稳定热源;岩石圈构造薄弱带如板块边缘带和切入岩石圈的深大走滑断裂构成了幔源热物质向上侵入的主要通道。(3)凹凸相间的构造格局和地下水流场主导了地壳浅部的热量分布,在浅部岩石热导率差异驱动形成的“热折射”效应下,热流由凹陷区向凸起区聚集,形成古潜山高温热异常。
High-temperature geothermal reservoirs with temperature above 150℃have been successively discovered in China—mainly in southern Xizang,Yunnan and Sichuan in the Mediterranean-Himalayan geothermal belt,and Taiwan region of China in the Pacific Rim geothermal belt.In recent years breakthroughs in high-temperature geothermal prospecting have also been made in cental and eastern North China.For example,in 2019 in Hebei,granite dry hot rock mass with a temperature of 151℃was drilled at a depth of 4000 m in Matouying.In 2020,a geothermal fluid of 167℃in high temperature gneiss fissure reservoir was drilled at 1586 m depth in Tianzhen County,Shanxi Province.And in 2023 in Shandong,a high-temperature Ordovician limestone karst reservoir with a temperature of 167.5℃was drilled at 4283 m depth in Zhuanxi area,Dongying City.It is therefore an urgent task to systematically study the formation of high-temperature geothermal reservoirs in this region as well as related exploration technologies.Taking the above three high-temperature geothermal fields as examples,this paper analyzes the dynamic process underlying the effect of regional crust-mantle structure,deep geological processes—such as crust-mantle upwelling and Moho uplift-on the shallow high-temperature thermal anomalies in the Earth’s crust.Combined with geophysical and geochemical studies and exploration results,this paper explains how deep geodynamic processes shape the Earth’s shallow geothermal field and constrain high-temperature thermal anomalies,and discusses technologies to identify deep heat sources,upwelling channels and thermal energy gathering structures.The paper also explores the formation mechanism of high-temperature geothermal reservoirs in typical locations and its significance for high-temperature geothermal exploration in central and eastern North China.Briefly,(1)under the far field effect of the India-Eurasia plate collision and subduction retreat of the Western Pacific plate,the destruction of the North China Craton(NCC)leads to deep geodynamic processes—such as lithospheric thinning,asthenospheric upwelling and thermal erosion,extensional rift basin and deep strike-slip fault development—which are the main driving forces behind the upwelling of mantle-derived molten material to the shallow crust.(2)There is a good corresponding relationship between a high conductivity-low velocity-low resistivity body,geochemical evidence and high-temperature geothermal resource distribution.Therefore,it is believed that the upward infiltration of molten materials causes shallow thermal anomalies,and the molten/semi-molten magma sac in the crust provides a stable heat source to form high-temperature geothermal reservoirs.The weak lithospheric structures-such as plate margin zones and deep strike-slip faults—cut into the lithosphere,constituting the main channels for the upward infiltration of the molten material.(3)The concave-convex tectonic pattern and groundwater flow field mainly control the heat distribution in the shallow crust.Under the“thermal refraction”effect driven by the difference in thermal conductivity of shallow rocks,heat flow accumulates from the sag to the uplift,forming high-temperature thermal anomalies in ancient buried hills.
作者
康凤新
张保建
崔洋
姚松
史猛
秦鹏
隋海波
郑婷婷
李嘉龙
杨海涛
李传磊
刘春伟
KANG Fengxin;ZHANG Baojian;CUI Yang;YAO Song;SHI Meng;QIN Peng;SUI Haibo;ZHENG Tingting;LI Jialong;YANG Haitao;LI Chuanlei;LIU Chunwei(College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China;Shandong Provincial Key Laboratory of Geothermal Clean Energy,Jining 272000,China;Chinese Academy of Geological Sciences,Beijing 100037,China;Shandong Provincial Geo-mineral Engineering Exploration Institute,Jinan 250014,China;Shandong No.3 Exploration Institute of Geology and Mineral Resources,Yantai 264000,China;Shandong Provincial Territorial Spatial Ecological Restoration Center,Jinan 250014,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2024年第6期31-51,共21页
Earth Science Frontiers
基金
国家自然科学基金项目(42072331,U1906209)
泰山学者工程专项经费资助项目(tstp20230626)
中国工程科技发展战略山东研究院咨询研究项目(202302SDZD02)。
关键词
深部地球动力
幔源热
上涌通道
聚热
高温热储
华北板块
deep dynamic processes
mantle-derived heat
upwelling channel
heat accumulation
high temperature reservoir
central and eastern North China Block
作者简介
康凤新(1968-),男,教授,博士生导师,主要从事水文地质、地热地质研究工作。E-mail:kangfengxin@126.com;通信作者:张保建(1972-),男,博士,正高级工程师,从事地热、水文及环境地质研究工作。E-mail:zbjsddk@126.com。
