中国大陆干热岩地热资源潜力评估

内蒙古中部地区处于板块结合部位，经历了多期构造活动和岩浆活动，浅层水热型地热资源丰富，但对其深部干热岩地热资源仍缺少深入研究。基于区域地质与构造背景、大地电磁探测结果与地热异常显示，系统探讨内蒙古中部地区干热岩地热资源成因机制与地球动力学过程，建立干热岩成因模式。研究表明：内蒙古中部地区深层干热岩型地热资源的热源主要为深部局部熔融体和残余高温岩浆囊，热流通道包括板块缝合带、区域深大断裂带及其交汇部位、次级断裂及塑性流变韧性剪切带等壳内薄弱层；干热岩储层主要为新生代基性侵入岩，即辉绿岩和辉长岩体，被高温岩浆和侵入体加热的花岗岩类也可作为研究区潜在干热岩储层；干热岩区域性盖层为白垩系、新近系和第四系沉积地层。西伯利亚板块与华北克拉通板块之间的大陆碰撞、拼合，形成易于破坏的碰撞带，晚中生代−新生代以来的古太平洋板块对华北板块的西向俯冲作用，导致岩石圈底部熔融，岩石圈伸展、减薄，地幔软流圈热物质上涌，并伴随强烈的新生代断裂与断陷活动，共同导致晚中生代−新生代岩浆、火山活动强烈。内蒙古中部地区存在3种聚热模式：Ⅰ. 新生代辉绿岩、辉长岩储层高温干热岩系统，为研究区优势干热岩储层；Ⅱ. 新生代以前花岗岩储层中高温干热岩系统，为潜力干热岩储层；Ⅲ. 浅部碎屑岩、花岗岩或变质岩储层水热系统，为浅层水热型优势储层。内蒙古中部地区浅部高温水热型地热系统与深部干热岩地热系统存在同源共生关系，浅层高温异常区的圈定对于深部干热岩的发现具有重要的指示意义。

Estimate of geothermal resources potential for hot dry rock in the continental area of China

Central Inner Mongolia, located at the junction of plates, has undergone multi-phase tectono-magmatic activities and boasts abundant shallow hydrothermal resources. However, there is a lack of in-depth research on deep hot dry rock (HDR) geothermal resources in this region. Based on the regional geological and tectonic settings, magnetotelluric sounding results, and geothermal anomaly manifestations, this study systematically explored the genetic mechanisms and geodynamic process of HDR geothermal resources in central Inner Mongolia and determined the genetic modes of HDRs. The results show that the major heat sources of deep HDR geothermal resources in the region include deep local melts and residual high-temperature magma pockets, with heat flow channels encompassing suture zones between plates, regional deep-seated fault zones and their intersections, secondary faults, and weak layers such as ductile shear zones with plastic rheological properties in the crust. The HDR reservoirs in central Inner Mongolia primarily comprise Cenozoic mafic intrusive rocks, namely diabase and gabbro. Additionally, granites heated by high-temperature magmas and intrusive bodies are potential HDR reservoirs in the study area. The regional cap rocks of HDRs include the Cretaceous, Neogene and Quaternary sedimentary strata. The continental collision and amalgamation between the Siberian plate and the North China Craton led to the formation of collision zones that are prone to be destroyed. The subduction of the Paleo-Pacific Plate to the North China plate in the west since the Late Mesozoic Cenozoic resulted in the melting of the lithosphere bottom, the extension and thinning of the lithosphere, and the upwelling of thermal materials in the mantle asthenosphere. These, together with the accompanied intense activity of Cenozoic faults and fault depressions, jointly led to the strong magmatic and volcanic activity during the Late Mesozoic and Cenozoic. There are three heat accumulation modes in central Inner Mongolia: (1) The high-temperature HDR systems of Cenozoic diabase and gabbro reservoirs are dominant HDR reservoir in the region. (2) The moderately-high-temperature HDR systems of granite reservoirs prior to the Cenozoic are potential HDR reservoirs. (3) The hydrothermal systems of shallow clastic-rock, granite, or metamorphic rock reservoirs are dominant shallow hydrothermal reservoirs. Since shallow high-temperature hydrothermal systems are consanguineous and paragenetic with deep HDR geothermal systems in central Inner Mongolia, delineating shallow high-temperature anomalous areas will provide indicators for the discovery of deep HDRs.