The Gravity And Magnetic Characteristics Of The Central Segment Of The Qinling Orogen And Its Adjacent Area

The study area of this article is the central segment of Qinling orogen and the neighbouring Yangtze Block about E105°～110°,N30°～35°.This area,is the place where the main plots of Mainland China intersection in the Qinling orogenic belt and is also the important area for orogenic belt to contact and shift, has always been the research hotspot and focus in the geological field.Based on the previous studies, the author studied the basement structure and structure characteristics of Qinling orogenic belt and its adjacent areas by the result of doing gravity and magnetic correspondence and the information of MT and Seismic profile. The author also does joint inversion of gravity and magnetic for existing geological profiles in the study area.The result shows that:(1)The Crustal structure of Qinling orogenic belt is complicated,the middle of the southern edge of North China Block, the central region of Sorth Qinling and the northern edge of the Yangtze Block is normal crustal structure,southern edge of North China Block and Sorth Qinling has Non-normal, non-stable crustal structure except their central regions(Fengxian-baoji), the interior of Sichuan Basin performances as Non-normal crustal structure;(2)Compareing the plane correspondence analysis and geological structure chart, the author finds that correlation coefficient conversion belt and tectonic boundary area corresponding well.By the Correlation coefficient conversion belt from plane correspondence analysis, the author infers two concealed fracture in the study area and judges out their trend and depth. In different depth of the earth’s crust, according to the heavy magnetic homologous regions in the northwestern margin of Ankang circle draw by corresponding coefficient R isoline, the author infers that the basement of Yangtze plate negotiate the ChengKou-Banfang fracture and the pushover distance to the north east is about110～120km.(3)The author finds that part of the cover and base of the Yangtze block is inserted under the Qinling Proterozoic strata.by doing joint inversion of gravity and magnetic.