摘要
共和盆地干热岩是我国首次钻获的干热岩,围绕其成因机制还存在诸多争议。基于前人资料和我们的热物性测试、地球化学及地球物理探测成果,通过综合研究,阐述了共和盆地干热岩成因机制与地球动力学过程:(1)印度与欧亚板块晚碰撞及后碰撞等一系列构造活动,导致了青藏高原北部的隆升和软流圈上涌、热侵等深部动力过程,在高原隆升蓄积的重力势能及其导致的重力浮力、青藏高原东北缘的侧向挤压应力、地幔拖曳力、软流圈热物质上侵热力等综合作用下,壳幔通道流沿岩石圈薄弱层(带)整体自西南向青藏高原东北部和共和盆地东北部流动。(2)板块(地块)缝合带、塑性流变韧性剪切带或高导低速体、深大走滑断裂带及其交汇部位等岩石圈薄弱层(带),是深部热物质自深至浅运移的壳幔通道。(3)深部地质结构的不均一使来自深部的热量在地壳浅部形成不均一性的聚集;岩石圈浅部的地下水活动、沉积/剥蚀作用与深部的岩石圈变形以及岩浆热对流等物质运动方式对热流的扰动;深部热流向热导率高的花岗岩类侧向运移等这些岩石圈热量自深至浅的不均一分配。本文突破了以往单因素和少数控热因素的共和盆地干热岩成因认识,阐明了由源(热源、力源)、通道到储、盖(层)的干热岩综合成因机制。
Hot dry rock of the Gonghe Basin is the first hot dry rock drilled in China,but its formation mechanism is still unclear.Based on previous data,combined with our thermophysical property testing and geochemical,geophysical investigation results,this paper discusses the genesis and geodynamic evolution of hot dry rock in the Gonghe Basin:(1)A series of tectonic activities,such as late collisions between the Indian and Eurasian plates and related post-collisional events lead to deep dynamic processes in the northern Qinghai-Tibetan Plateau,including tectonic uplift,asthenosphere upwelling and thermal intrusion.Under the combined effects of gravitational energy amassed by tectonic uplift and resulting gravity buoyancy,lateral extrusion stress in the northeastern margin of the Qinghai-Tibetan Plateau,mantle drag force,and thermal intrusion of the asthenosphere,crustal and mantle fluids flow from southwest to northeast along weak lithospheric layers(zones)in the Tibetan Plateau and Gonghe Basin.(2)Weak lithospheric layers(zones),such as plate(block)suture zones,plastic rheological ductile shear zones or high conductivity,low velocity bodies,and deep,large strike-slip fault zones and fault intersections,are channels for mantle melt migration to the Earth’s crust.(3)Geological heterogeneity of the Earth’s deep structure leads to nonuniform accumulation of heat produced at depth in the shallow crust.Heat flow is disturbed by groundwater activity and sedimentation/denudation in the shallow lithosphere,lithospheric deformation in the deep lithosphere,and magma convection in the aesthenosphere,while deep-heat flows laterally toward high-thermal conductivity granites,resulting in uneven heat distribution from deep to shallow in the lithosphere.This paper makes a breakthrough from the previous understanding of the genesis of hot dry rock in the Gonghe Basin based on a single factor and a few heat-control factors,and expounds a comprehensive genetic mechanism of hot dry rock,from heat source,heat migration driving force and channel,to reservoir and cap(layer).
作者
张保建
雷玉德
赵振
唐显春
罗银飞
王贵玲
高俊
张代磊
ZHANG Baojian;LEI Yude;ZHAO Zhen;TANG Xianchun;LUO Yinfei;WANG Guiling;GAO Jun;ZHANG Dailei(Chinese Academy of Geological Sciences,Beijing 100037,China;SinoProbe Center,Ministry of Natural Resources,Beijing 100037,China;Technology Innovation Center of Geothermal and Hot Dry Rock Exploration and Development,Ministry of Natural Resources,Shijiazhuang 050061,China;Key Lab of Geo-Environment Qinghai Province,Xining 810007,China;Environmental Geological Prospecting Bureau of Qinghai Province,Xining 810007,China;No.906 Engineering Survey and Design Institute of Qinghai Province,Xining 810007,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2023年第5期384-401,共18页
Earth Science Frontiers
基金
青海省科学技术厅应用基础研究项目(2019-ZJ-7062)。
关键词
共和盆地
干热岩
综合成因机制
地球动力学
壳幔源通道流
Gonghe Basin
hot dry rock
comprehensive genetic mechanism
geodynamics
crust-mantle-sourced channel fluid
