Characteristics Of Gravity And Magnetic Anomalies And Their Tectonic Significance Of The Kolbeinsey Ridge In The Arctic

The Kolbeinsey Ridge is located in the western Norway-Greenland Sea in the Arctic region.It was mainly formed by a series of seafloor spreading movements after the separation of Norway and Greenland.The surrounding areas of the Kolbeinsey Ridge mainly include Greenland,Iceland,Jan Mayen,and Mohns Ridge.The adjacent areas have undergone complex tectonic movements,and the structural changes in the lithosphere are also relatively strong.Conducting work on regional anomaly characteristics and deep structures,including the crustal density,deep and large faults,Moho depth,Curie depth,and tectonic units,is conducive to forming a systematic understanding of fundamental issues such as regional geodynamics and tectonic evolution.Using 1:500 000-1:100 0000 gravity and magnetic anomaly data,this paper conducts potential field conversion and separation through upward continuation,sliding average,and vertical second derivative methods,and uses horizontal derivative methods to identify and divide faults.2.5D gravity and magnetic inversion is used to study the profile of the study area.Linear regression method and three-dimensional magnetic interface inversion method are used to perform Moho depth inversion and Curie depth inversion,respectively.Based on previous achievements in gravity,magnetic,seismic,geothermal,and rock physical properties in the study area and adjacent areas,we obtained the characteristics of gravity and magnetic anomalies and their origins of the Kolbeinsey Ridge,and further studied its deep structure and tectonic significance.The research results show that:(1)The characteristics of gravity and magnetic anomalies of the Kolbeinsey Ridge are obvious,and the strike is macroscopically NNE direction,indicating that the geological body of the Kolbeinsey Ridge is NNE spreading.It is speculated that the causes of local abnormal changes are mainly related to local density changes in the stratum,the West Jan Mayen fault zone,and basalt enrichment.In addition,the blocking characteristics of the anomaly are also very consistent with the display of geological structure zoning.(2)The Kolbeinsey Ridge structure is relatively developed,with a total of 6 deep and large faults divided.The strike of the deep and large faults is mainly in the NNE and near EW directions,and the deep and large faults basically control the macro contour of the structural zoning.(3)The Moho depth gradually rises from west to east and from south to north,which may be due to differences in crustal characteristics in the west,south,and east.Under the influence of tensile movement,the Moho surface of the Kolbeinsey ridge is uplifted,forming a Moho depth cascade zone;The depth variation of curie surface presents a shallow-deep-shallow feature from northwest to southeast,with an overall NNE trend,and the deep and large faults basically fit the depth fluctuation of the interface.Therefore,the study area has been divided into seven blocks from northwest to southeast.It is believed that the deep structural characteristics of the Kolbeinsey Ridge are significantly different from those of its surrounding areas due to various actions such as seafloor spreading and magma eruption.The upwelling of asthenospheric thermal material has further exacerbated the formation of regional rifts in the Kolbeinsey Ridge,making the oceanic ridge in this area have the characteristics of large-scale extensional movement.