甘肃省天水地区地热研究综述

    A review of geothermal research in Tianshui area of Gansu Province

    • 摘要: 甘肃省天水市位于甘肃东南部,该区平均大地热流值70.8mW/m2,高于我国大陆大地热流平均值,目前已发现6处水热型地热田,具有良好的地热勘查前景。天水地区地热研究基础较薄弱,缺乏对其整体地热资源形成的地质背景、地温场、热田成因模式等综合研究和评价。基于大量勘查资料及前人研究成果,本文首次绘制了天水地区的大地热流图以及地温梯度图,分析了其现今地温场特征;此外,本文概述了天水地区地热资源勘察现状并初步建立了地热田成因模式。研究表明,天水地区大地热流与地温梯度分布规律基本一致,整体表现为“西南高东北低”的特征,现今地温场分布特征整体主要受断裂控制,基底起伏也对其有影响。地热田(温泉)分布受断裂带控制,多出露于活动断裂交汇处。热源机制主要为深循环加热,断裂构造的发育起到导热、导水的作用,热储岩性为花岗岩和变质岩,上覆盖层为新近系及第四系地层,大气降水为地热水的主要补给水源。本文综述了天水地区的地热研究,总结了研究中存在的问题和局限性,并提出了未来研究的建议,为天水后续的地热研究和地热资源勘探开发提供了有益参考。

       

      Abstract: The Tianshui area is located in the southeastern part of Gansu Province, with an average heat flow of 70.8 mW/m2, which is higher than the average heat flow value in mainland China. Currently, six hydrothermal geothermal fields have been discovered in this area, indicating promising prospects for geothermal exploration. However, the research foundation of geothermal resources in the Tianshui area remains relatively weak, lacking comprehensive studies and evaluations of its geological background, geothermal field characteristics, and the genesis model of the thermal regime. Based on extensive survey data and previous research, this study delineates the heat flow and geothermal gradient distribution patterns in the Tianshui area for the first time. The results show that the heat flow and geothermal gradient exhibit an overall characteristic of "higher in the southwest and lower in the northeast". The distribution of the present geothermal field is mainly controlled by fault structures, and the fluctuation of the basement also plays a role. The distribution of geothermal fields (hot springs) is fault-controlled, mostly occurring at the intersections of active fault zones. The primary heat source mechanism is deep circulation heating, where the well-developed fault structures facilitate heat and fluid transport. The thermal reservoir lithology is dominated by granite and metamorphic rocks, overlain by Neogene and Quaternary sedimentary sequences. Atmospheric precipitation is the main source of geothermal water supply. This study provides an overview of the current status of geothermal research in the Tianshui area, summarizes the existing problems and limitations, and proposes suggestions for future research directions. The findings can serve as a valuable reference for subsequent geothermal research and exploration activities in the Tianshui region.

       

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