Research And Application Of Processing Methods Of Aeromagnetic Gradient Data In Three Directions

Magnetic prospecting is a basic subject of geological investigation,and it is one of the earliest and most mature geophysical research methods.Ground magnetic survey is easy to be interfered by seasonal factors,geographical factors and cultural factors,and has certain limitations.Aeromagnetic survey can avoid the interference of the above factors.Aeromagnetic prospecting is mainly used in the exploration of underground structures and the search for hidden solid mineral,petroleum,natural gas and other resources.Compared with aeromagnetic prospecting,aeromagnetic gradient prospecting does not need to be monitored daily.Apart from that,the aeromagnetic gradient data not only can provide abnormal information of deep formation,but also the shallow formation details.Thus,we can get larger and clearer amount of anomaly information from the aeromagnetic gradient prospecting data,which also has more advantage in marking out the location of abnormal bodies^[1][2].From the development of aeromagnetic prospecting,China's aeromagnetic prospecting is in the research stage of aeromagnetic gradient prospecting,which is far from the research level of other foreign countries.After years of doing research on the aeromagnetic measurement technology,our country has achieved great improvement on aeromagnetic gradient data measuring equipment,but for the work on aeromagnetic gradient data processing method still need to make more effort.As a result,working on the processing method of aeromagnetic gradient data will promote the widely application of the aeromagnetic gradient prospecting.This paper is mainly studied on the processing method of aeromagnetic gradient data which includes the following contents:?1?Studying in the processing method of reducing to the pole and upward continuation of the aeromagnetic gradient data,and has proved that the traditional processing method of reducing to the pole and upward continuation of the aeromagnetic anomaly data can also be applied in the magnetic gradient data.At the same time,through the combination model experimental study on the rule of the continuation of the aeromagnetic gradient data,it is proved that the rules are similar to the aeromagnetic anomaly,with the increasing depth of upward continuation,shallow source field anomalies are gradually disappeared.So,by compared with the upward continuation of the total aeromagnetic anomaly,the upper extension of aeromagnetic gradient data can amplifies the shallow anomaly.?2?Studying on the methods of marking out boundary by using the aeromagnetic gradient data,and define a new boundary identification method,named EVDT method,by improve the basic method named direction analytical signal.By comparing this new method with the other three boundary identification methods,named THDR method,TA method and Theta method respectively within the combine theory model test,it is confirmed that EVDT method has its'own advantage and is suitable in finding the boundary of the anomaly bodies.?3?It is confirmed that the processing of reducing to the pole and upward extension is useful and helpful by applying these two processing steps in the measured aeromagnetic gradient data of BaoDing.And through being compared with aeromagnetic anomaly data,the beneficial of aeromagnetic gradient data in accuracy and the advantage in recognizing anomaly bodies are both approved.?4?Applying these four boundary identification methods in the aeromagnetic gradient data of BaoDing,a total of 26 fractures are found in the area,and the lithology mapping,including three categories?acidic,basic and altered rock?,has been interpretated.?5?By processing the general aeromagnetic field data and the aeromagnetic gradient data of BaoDing,the work of working out the prospecting minerogenic has been finished,this area contains 4 areas of the I grade metal prospective areas and 3 areas of the II grade metal prospective areas.