Study On Gravity Anomaly Identification Of South Taihang Fault

Located in the middle of our country,Taihang Mountain is the dividing line between the Loess Plateau and the North China Plain.Its southern section is an important rich area of iron ore and copper in our country,and the fault structure can often control the form and occurrence of ore bodies,so studying the distribution of fault structure is of great significance for finding metal ore bodies.Gravity exploration is an economical and efficient exploration method with wide coverage.Gravity anomaly can reflect abundant geological structure information and is an important means to identify fault structures.Therefore,in combination with previous relevant research results,this paper uses satellite gravity data and regional geological data in the study area to conduct a comprehensive study on the southern Taihang Mountain fault structural system,basement relief and other aspects.The research results can provide geophysical basis for the structural geology,hydrogeology and engineering geology of the southern Taihang Mountain.It also provides some reference value for searching copper iron ore and groundwater distribution in this area in the future.In this paper,a variety of potential field separation methods are used to deal with the Bouguer gravity anomaly in the study area,and the regional gravity anomaly and local gravity anomaly are analyzed and explained.The vertical second derivative and normalized standard deviation method are used to divide the fault structure,the horizontal cosine method is used to infer the geological strike,and the regional geological structure of South Taihang is studied comprehensively.Finally,Parker method was used to invert the basement,infer the basement fluctuation,and discuss the development characteristics of the strata.Finally,the main results and conclusions are as follows:(1)On the whole,the gravity anomalies in South Taihang are mainly distributed in the NNE and NE direction,which are reflected as the gravity anomalies in Taihang Mountain uplift and North China Plain from west to east,and the gravity anomalies are getting higher and higher from west to east.There are obvious changes in gravity anomalies near the Jinhuo fault and the piedmont fault on both sides of Taihang Mountain.Through the analysis of regional anomalies and local anomalies,it is found that the height of regional gravity anomalies is reflected by the fluctuation of basement.The local abnormal high value area may be caused by local basement uplift or ancient strata out exposure,and the local abnormal low value area may be caused by local basement depression,or the thickening of overlying strata and intermediate acid intrusive rocks.(2)The structural evolution of the study area is complex,and many fault zones have been generated after multiple stages of tectonic movement.A variety of boundary identification methods are used to identify 19 fault structures,which mainly develop into NNE-trending faults and NWW-trending faults,and these faults control the development of nearby strata to a certain extent.(3)to bottom by Parker fermentation inversion profile line,the results show that from the west side of Taihang uplift area to the north China plain area basement depth becomes shallow gradually,Taihang mountains near Cenozoic formation development is less,the upper strata exposed more,and cover thicker,basement buried depth is deeper,the north China plain area is covered by Cenozoic strata,and the thickness of the thinner,the basement depth is shallow.