Characterization Of Heavy Magnetic Anomalies And Deep Structure Of Aegir Ridge In Arctic Region

In order to study the fracture tectonics and deep tectonic features of Aegir Ridge and adjacent areas,and to provide more geophysical information for the region,this paper systematically analyzed and processed the gravity magnetic data of the area.The correlation and difference analysis between the global gravity database V29 and ship-measured gravity data,and the global magnetic anomaly EMAG2v3 and ship-measured magnetic data were conducted respectively,and the quality of the four data was evaluated comprehensively,and the results showed that the ship-measured gravity and magnetic data were of higher quality than the V29 library and the global magnetic anomaly EMAG2v3 data.Therefore,the latest ship-measured gravity and magnetic data were filled in the global gravity database V29 and global magnetic anomaly EMAG2v3 library data,and anomaly separation,sliding average and heavy magnetic field source boundary identification methods were processed.Based on the characteristics of anomalies: anomalous polar zone,anomalous zone orientation,anomalous gradient zone variation,etc.,the geological and tectonic characteristics of the study area were comprehensively analyzed,and it was obtained that: the gravity and magnetic anomalies show NNE-NW-NE directional spreading,reflecting the regional tectonic distribution characteristics of the area;the gravity anomalies show high and low zonation,indicating that the basement of the area also shows the layout of uplift and depression,and the regional differences of magnetic anomalies indicate the regional differences of the basement of the area.The regional differences in magnetic anomalies indicate regional differences in the lithology of the area.In view of the lack of fracture and independent tectonic unit delineation and interpretation results in the Aegir ridge and adjacent areas,the study area was divided into fractures and tectonic units based on the characteristics of gravity and magnetic anomalies and previous research data.Based on the correspondence between anomalous features and fractures,four groups of fractures,NNE-oriented,NWW-oriented,NW-oriented and near-SN-oriented,are classified as Fractures F1-F7 in order,and these seven fractures play an important role in controlling the basement structure,nature and uplift and depression frame.The Aegir Ridge and its neighboring areas can be divided into seven tectonic units,including Mohns Ridge,Jan Mayen Microcline,East Jan Mayen Fracture Zone,West Jan Mayen Fracture Zone,Aegir Ridge,East Jan Mayen Deep Sea Basin,and Norway Deep Sea Basin,with fault contacts between the tectonic units.Based on the gravity anomaly and magnetization pole anomaly,the depth of Moho surface and the average depth inside the curved surface were obtained by using the heavy magnetic property inversion method.The Moho surface is macroscopically spreading in a near north-south direction,and the overall characteristics are "deep in the west and shallow in the east";the characteristics of the interior show that "the southern part of the study area is macroscopically spreading in a north-east direction,and the northern part is spreading in a north-west direction";the difference between the Moho surface and the interior depth is zero.There are two lines of difference between the Moho surface and the depth of the Curie,and their directions are not obvious.The results of the study show that the depth-zero value line between the Curie and Moho surfaces is an ocean-land transition zone,with oceanic and land crust on both sides,and the longitudinal features of the seismic profile are consistent with the deep tectonic features.