天水街子温泉控热推覆构造的发现及地热前景探讨

DOSCOVERY OF GEOTHERMAL NAPPE STRUCTURE BY GEOPHYSIVCAL EXPLORATION METHOD ANG DISCUSSION OF GEOTHERMAL PROSPECT OF JIEZHI THERMAL SPRING IN TIANSHUI

天水街子温泉通过可控源音频大地电磁测深,在温泉所在的温家峡及其附近深部发现的低阻电性层呈层状分布,其深度与以往钻孔中所见地下热水部位一致,推断此低阻层为热水通道。结合地表地质和地面磁测推测逆断层与上盘推覆体(牵引背斜)构成推覆构造,逆冲断层为阻水构造,活动上盘岩块破碎和裂隙发育是地下热水良好通道,控制着中低温地热田分布。街子温家峡温泉和黄家峡有利热储地段,地下热水具有充沛的补给来源、较好储存和开采条件,具有进一步钻探开发扩大地热利用的远景。

At Wengjiaxia and the adjacent area where is the site of geothermal spring, the measurements by controllable source audio magnetotelluric sounding （CSAMT） show that distribution of the electric layer of lower electric resistance is bedded, that the depth of the layer is same as the depth where underground geothermal water was discovered in borehole. This layer is inferred to be geothermal conduit. By combination of surface geological condition and result of ground magnetic survey, it is supposed that the nappe structure is formed by reversed fault and upper nappe （tractive anticline）, that thrusting fault is the structure blocking geothermal water, the mobile hanging wall is the good geothermal water conduit due to crushed rock and fissures development which control the distribution of middle and lower temperature geothermal water field. The area of Jiezi - Wenjiaquan spring and Huangjiaxia is a favorable geothermal reservoir which is valuable to do further drilling exploration because underground water has a good source.