西藏日喀则市查孜地热田地质构造特征与形成机制

Geological Structure Characteristics and Genetic Mechanism of the Cazê Geothermal Field in Xikazê, Tibet

查孜地热田位于冈底斯-念青唐古拉断块隆起区之当惹雍错-许如错南北向地堑区,区内岩浆岩分布较为广泛,活动性断裂较为发育,拥有形成地热的良好地质条件。结合区域地质背景和地热田地质及地球物理场的研究成果,分析了查孜地热田地热资源的形成背景、赋存条件和分布规律。研究表明,地热田的热储层为古近纪古-始新统火山岩。大气降水及融雪水的入渗补给为地热水提供了丰富的水源,活动性断裂构成了地热水深循环的通道,广泛分布的岩浆岩体为地热水提供热能来源,本区地下热水的成因类型可划归为岩浆岩-构造断裂型。

The Cazê geothermal field is located in the NS-trending Tangra Yumco – Xuru Co graben of the Gangdisê – Nyainqêntanglha fault block where magmatite are widely exposed and active faults are developed. Based on the research results of regional geological setting and geological and geophysical fields of the geothermal field, this paper has a discussion on formation background, occurrence conditions and distribution rules of the Cazê geothermal field. The study results show that the thermal reservoir of the geothermal field is volcanic rock during Paleocene-Eocene epoch. Atmospheric precipitation and snowmelt water supply provide abundant water sources for the geothermal field, while active faults form the deep circulation channels of geothermal water, and widespread magmatite masses provide thermal energy for the geothermal water. The genetic type of the underground thermal water in this area belongs to magmatite-tectonic fault type.