青藏高原东构造结林芝地热田浅部典型电性结构及热储关系  

Typical electrical structure and heat storage relationship of the shallow surface in the Nyingchi geothermal field,Eastern Himalayan Syntaxis,Qinghai—Xizang(Tibet)Plateau

作　　者：李栋 祝杰 叶高峰[1,3] 金胜[1,3] 董浩[1] 魏文博[1,3] LI Dong;ZHU Jie;YE Gaofeng;JIN Sheng;DONG Hao;WEI Wenbo(School of Geophysics and Information Technology,China University of Geosciences,Beijing100083;Civil—Military Integration Center of China Geological Survey,Chengdu610036;Key Laboratory of Intraplate Volcanoes and Earthquakes(China University of Geosciences,Beijing),Ministry of Education,Beijing100083)

机构地区：[1]中国地质大学(北京)地球物理与信息技术学院,北京100083 [2]中国地质调查局军民融合地质调查中心,成都610036 [3]陆内火山与地震教育部重点实验室(中国地质大学,北京),北京100083

出　　处：《地质论评》2024年第2期577-590,共14页Geological Review

基　　金：中国地质调查局军民融合地质调查中心资助项目(编号:DD20211548)的成果。

摘　　要：约40 Ma以来,受控于印度板块的俯冲及后期演化,青藏高原喜马拉雅山系东构造结成为了板块活动最强烈的地区之一;由于深部动力学过程中的浅表响应,该地区地热资源极为丰富。笔者等通过对两条音频大地电磁(AMT)测线进行数据处理与分析,查明了测点覆盖区域范围内二维电性结构及主要存在的深大断裂。依据电性结构推测研究区地下1 km深度范围内可分为4层,浅部低阻层为松散砂泥卵石层,下伏的中阻为砾卵石层,其下的低阻为砂岩、板岩、页岩强风化层,最底部的中高阻层推测为古元古界林芝岩群真巴岩组以片岩、花岗岩为主的地层。结合以往大地电磁测深及地震研究发现的地下10~20 km存在大规模近东西向展布且向上延伸熔融流变导致的低速高导体,推测可能是该地区深部热源所在。进一步通过对深部及浅部电阻率模型的综合对比研究,基于地热地质背景、电性结构特征,探讨了该地区的深部热源及热储关系。To identify the four geothermal elements of source,channel,cover,and reservoir in the Nyingchi geothermal field in the eastern Himalayan Syntaxis of the Qinghai—Xizang(Tibet)Plateau,writers completed a two-dimensional inversion of two audio-frequency magnetotelluric(AMT)survey lines and proposed two-dimensional resistivity models of the Nyingchi geothermal field.Combining with previous magnetotelluric and seismic results,the following understandings were obtained:①There is a low velocity and high conductive body at depths of 10~20 km in the study area,which is formed due to the large scale near east—west distribution and upward extension of the crust.②The deep heat source is composed of the crustal melting of low velocity and high conductive body and radioactive heat production.③The deep faults in the upper crust are the main channels for the upwelling of hot materials,and the Lulang—Yigong fault and the Jiali—Chayu fault are important thermal conduction channels due to high-pressure shear.④A high resistance layer 10 km thick in the upper crust is a cover layer of the deep heat sources,and the shallow Triassic sandstone slate,strong regolith,and the schist dominated by the Zhenba Formation of the Meso—Neoproterozoic Lingzhi Group serve as thermal reservoirs.⑤The atmospheric precipitation and groundwater permeate and circulate along the shallow small fracture to the high-temperature heat storage location,and then form high-temperature water resources.

关 键 词：地热勘探 音频大地电磁测深法 青藏高原东构造结 电性结构 林芝地热田 

分 类 号：P314[天文地球—固体地球物理学]