川东断褶带仙女山温泉地质成因浅析

摘要

Hot springs with a high discharge rate occur along the axes of steep anticlines in a fault–fold belt in the eastern Sichuan Basin.The springs occur close to rivers,with their distribution controlled by tectonic fractures and fluvial downcutting.The Xiannvshan hot spring emerges from fractures in sandstone of the Triassic Xujiahe Formation in the area of the northernmost Tongluoxia anticline in the eastern Sichuan Basin.The water temperature of the hot springs is 38–40°C.Calcareous tufa are deposited at the water outlet.Based on the geothermal gradient and geological structure in the area,the groundwater is calculated to circulate to depths of more than 1000 m,and upflow to the surface occurs within rocks with a high infiltration ratio.%川东断褶带背斜高陡,沿断褶带泉眼众多,流量丰沛。受构造裂隙和河流切割的双重作用,在河流切割低点多可见温泉出露。仙女山温泉位于川东断褶带铜锣峡构造最北端三叠系下统须家河组砂岩地层中的浅表裂隙当中,泉眼温度38~40℃,泉口有青绿色泉华沉淀。用地温梯度法估算出地下水循环深度略大于1000m。对比当地地层为嘉陵江组的深层地下水,结合区域地质构造,认为仙女山温泉地下水沿着高渗透率岩溶裂隙岩层上升成泉。