地学前缘 ›› 2025, Vol. 32 ›› Issue (1): 367-379.DOI: 10.13745/j.esf.sf.2024.1.10

• “印度欧亚大陆碰撞及其远程效应”专栏之十一 • 上一篇    下一篇

汾渭地堑中、深层地热资源富集背景与形成机制

刘德民1(), 张昌生2,3, 陆婉玲1, 韦梅华2,3, 祁焱雅1, 刘菲1, 赵悦1, 姜淮1   

  1. 1.中国地质大学(武汉)地球科学学院, 湖北 武汉 430074
    2.中国地质大学(武汉)地球物理与空间信息学院, 湖北 武汉 430074
    3.山西省地质工程勘察院有限公司, 山西 太原 030024
  • 收稿日期:2023-08-08 修回日期:2024-10-20 出版日期:2025-01-25 发布日期:2025-01-15
  • 作者简介:刘德民(1975—),男,博士,副教授,主要从事构造地质学与地热地质学方面的教学和研究工作。E-mail: 5guc@163.com
  • 基金资助:
    中国地质大学(武汉)研究生联合培养实践基地建设项目(YJC2021506);山西省天镇县水桶寺村一带深部地热成因研究项目(2021016905);山西省忻州奇村—顿村一带干热岩地热资源调查项目(2022016044);大同盆地重点地区深部高温地热资源详查项目(2021-0009-G009-C05)

Enrichment background and formation mechanism of middle- and deep-geothermal resources in the Fenwei Graben

LIU Demin1(), ZHANG Changsheng2,3, LU Wanling1, WEI Meihua2,3, QI Yanya1, LIU Fei1, ZHAO Yue1, JIANG Huai1   

  1. 1. School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan 430074, China
    2. School of Geophysics and Geomatics, China University of Geosciences (Wuhan), Wuhan 430074, China
    3. Geological Engineering Survey Institute Co., Ltd. of Shanxi Province, Taiyuan 030024, China
  • Received:2023-08-08 Revised:2024-10-20 Online:2025-01-25 Published:2025-01-15

摘要:

汾渭地堑中、深层地热资源较富集,但其成因机制不明。为了更有效地勘探开发这些资源,首先必须弄清楚其形成的地质背景和热聚敛成因。在前人研究成果的基础上,综合分析了汾渭地堑构造演化与动力学背景,深部热构造特征,源、通、储、盖条件,并探讨了其热聚敛机制。印度-欧亚板块碰撞的远程效应形成了汾渭地堑新生代伸展拉张作用;软流圈底辟上涌,上地幔热隆起,莫霍面和居里面抬升,中、浅层低速高导体形成,地壳拉张减薄,固态剪切脆-韧性变形是中、深层地热资源形成的基础。新生代强烈的伸展拉张和特殊的构造格局是有利的控热构造,地幔传导热是目标热储最根本的动态热源,埋藏较浅的上地幔内和壳内的低速高导层是良好的导热体和热能汇集中心,是中、深层热储的直接热源和震源层,切割较深并在新生代具有强烈活动的边山断裂和控盆断裂具有良好的导热功能,是良好的导热构造和释热构造;夹有孔隙极为发育的火山岩的厚层状新生代松散沉积物,具有良好的阻热保温效果,是优质的热盖层。发育韧性剪切变形的变质基底不仅是干热岩型地热资源(固热能)的目标层,也是浅层水热型地热资源良好的热源层。源、通、储、盖四位一体的高效热聚敛地热系统促进了优质中、深层地热资源的形成和富集。

关键词: 地热资源, 地热系统, 控热构造系统, 形成机制, 汾渭地堑

Abstract:

Geothermal resources in the middle and deep layers of the Fenwei Graben exhibit considerable development, yet their genetic mechanism remains elusive. A thorough understanding of the geological background and the cause of thermal convergence is essential for improving exploration and exploitation efficiency. Building on previous research, this paper provides a comprehensive analysis of the deep thermal structural characteristics, structural evolution, genetic mechanisms, and the source, migration pathways, reservoirs, and sealing conditions of the Fenwei Graben. Additionally, it explores the mechanisms of driving thermal convergence in the region. The formation of middle and deep geothermal resources in the Fenwei Graben is rooted in a complex geological framework, with Cenozoic tectonic processes playing a pivotal role in the development of medium- and high-temperature reservoirs. The Cenozoic extension of the Fenwei Graben is primarily driven by the distant effects of the Indian-Eurasian plate collision. Key factors contributing to the formation of geothermal resources in the region include asthenospheric diapir upwelling, the development of low-velocity, high-conductivity zones in the middle and shallow layers, crustal stretching and thinning, and solid-shear ductile deformation. Mantle heat conduction serves as the primary dynamic heat source for the target geothermal reservoir, with shallowly embedded low-velocity, high-conductivity layers within the upper mantle and crust acting as efficient heat conductors and energy accumulation centers. These layers function as direct heat sources and focal points for medium- and deep-thermal reservoirs. The significant extension and tension during the Cenozoic era, combined with distinct structural patterns, provide favorable thermal control structures. Marginal faults and basin-controlling faults, characterized by deep incisions and active Cenozoic tectonics, exhibit excellent heat conduction properties, playing a crucial role in the formation and distribution of geothermal resources. These faults act as efficient pathways for heat conduction and release. The thick Cenozoic loose sediments with extensively developed pores, along with volcanic rocks characterized by low thermal conductivity and excellent heat retention, serve as high-quality thermal capping layers. The metamorphic basement, marked by ductile shear deformation, functions both as the target layer for dry hot rock geothermal resources (solid heat energy) and as an effective heat source layer for shallow hydrothermal geothermal systems. As a result, the Fenwei Graben boasts an exceptional thermal accumulation system, integrating heat sources, pathways, reservoirs, and capping layers, which collectively support the enrichment of high-quality geothermal resources.

Key words: geothermal resources, geothermal system, thermal control structure system, formation mechanism, Fenwei Graben

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