西安毛西磁异常的地质意义

本文阐述了应用地面磁测在西安东郊发现和圈定了毛西磁异常;根据异常区的地质和地球物理特征,作出了磁异常的定性和定量解释,推断它是中生代燕山期花岗岩侵入体的反映,顶部最小埋深约1500m;电测深结果支持了这个推断;重力勘探资料揭示了这个花岗岩侵入体处于灞桥断阶两组断裂带的交接部位;花岗岩作为热源及断裂带作为通道,使毛西磁异常是西安寻找地热田最有远景的地区。

The Geological Significance of Maoxi Magnetic Anomaly in Xi'an

By means of grond magnetic survey, Maoxi magnetic anomaly was found and delineated in the east subturb of Xi'an. Qualitative and quantitative interpretation of the magnetic anomaly is made in the light of the analysis of the geological and geophysical characteristics of the anomalous region, it is deduced that the magnetic anomaly reflects the granite intrusion dated back to Yan Shan movement period in Mesozoic Era, and that the minimum buried depth on the top of the intrusion is about 1500m. This deduction is supported by electrical sounding. The data of gravity prospecting reveals that the granite intrusion is located at the joint between two fault zones in Ba Qiao fault bench. As the granite is the geothermal source and the fault zone is the passage, Maoxi magnetic anomaly might be the most promising region of geothermal field in Xi'an.