| Qinling-Daba Orogen and its neighboring regions occupies a very important positionin the form of tectonic, basin-mountain coupling, orogenic belt forming and its deepdynamical process, it has control actions in mountain formations, basin formations, rocksformations, minerals formations and disaster formations of the eastern continent interior.From the Yangtze craton and the North China craton extrusion, collision and Qinling-Dabaorogenic uplift, the Pacific Plate and the Eurasian Plate subduction each other and form anarc of tension in eastern, the Indian and Eurasian collision between the continents toextrusion and subsequent uplift of the Tibetan Plateau, constitutive relations drawkinematics and dynamics of each chunk interactions of the eastern part. Ordos Basin islocated in north-central region of the continent, it is an important part of the North Chinacraton, and it is a very important country of the tectonic activities, the basin hasexperienced different stages, different directions and different attributes tectonic stress,eventually it formed a diverse and highly complex peripheral structural pattern; OrdosBasin is relatively stable in internal tectonic activities, and it accepted stable deposition fora long time to, so the basin is rich in oil, gas, coal and other fossil fuels and some metalmineral resources.Qinling-Daba Orogen is a important composite orogenic belt, which formed in theearly Paleozoic, the North China craton and the Yangtze craton opposite movement,squeezing, Qinling-Daba Orogen formed by the collision uplift, then it experienced a long time of intra-continental orogenic tectonic and magmatic activity is frequent, so itsgeological structure and lithology distribution is very complicated; Qinling orogenic belt isa very important polymetallic metallogenic, it provides lots of metallic mineral resourcesfor our country industrialization and modernization. Sichuan Basin is a sea-land duplexsedimentary basin, which is located in the western margin of the Yangtze craton andexperienced the Yanshan and Himalayan tectonic movement, leaded to folds formation inthe region, deformation and deposition. Sichuan Basin is an important oil and gas energybase of China, different people have done some geological and geophysical survey anddiscovered lots of oil and gas reserves in this region over the years.Since the eighties of the last century, many geologists and geophysicists have done alot of research work about Qinling-Daba orogenic belt, Ordos Basin and Sichuan Basinfrom different research directions, and obtained a lot of fruitful new understanding, butmost of these work is based on geological and geomorphological features or be derivedshallow to analyze a series of studies, so it will be difficult to outline the deep structure anddynamic processes. Apparently it will bring some limitations based on the above partial,fragmented and less crude data to infer the deep structure and dynamic processes, and itwill cause some interference on the interpretation based on existing geological priori theory,So it will greatly limits the holistic research about Qinling-Daba orogenic belt and itsadjacent area, particularly deep understanding of material properties and structural patternsand deep dynamic process of the Qinling-Daba orogenic belt. There is little study about therelationship and the interaction process between three blocks together so far, and mostresearch of the Qinling orogenic belt distribute in the East and the West Qinling Qinlingregion, and mainly based on geological and geochemical evidence, This is the first time toobserve precision geophysical field across the North China Craton, Qinling-Daba orogenicbelt and the Yangtze craton. The research of Qinling-daba orogenic belt mechanism, movement and determine thesouth and north border, to explore the relationship between the north China craton and theYangtze craton is an very important part of the tectonic evolution of the Chinese mainland.According to the latest high precision geomagnetic combine with1:100,000and1:200,000aeromagnetic data across the Southern Ordos Basin-Weihe Basin–Qinling-Daba orogenicbelt–Northeast corner of Sichuan Basin, Scilicet the Yulin-Xianyang-Wanyuan-Fulingcombined geophysical profiles, analysed the pattern of magnetic anomaly field,constructed partition and crystalline basement fluctuation characteristics of the study areathrough data processing and inversion. The result shows that there are obvious differencesbetween different tectonic units. Southern Ordos Basin has uplifted and been denudationdue to Yanshan movement, crystalline basement is relatively shallow;The Weihe basin andNortheastern of Sichuan Basin have received long-term sedimentation, crystallinebasement is relatively deep; Qinling-Daba orogenic belt has experienced a long-termcollision, estrusion and intracontinental orogenesis, the distribution of stratum andlithology and structure is very unequilibrated, interchanging and migration of substanceand energy is present in deep.Through the analysis of magnetic anomaly data, and based on the magnetic sourcebody buried deep when there exists faults, and the distribution is extremely uneven, thesecharacteristics indicate that there exist exchanging of material and substances betweendeep and shallow and these faults become their migration path. The curve of Qinlingorogenic belt is very similar to the horizontal magnetic anomalies, and its two extremepoints is its north-south border, so we considere the northern boundary of the Qinling-Dabaorogenic belt located in the northern margin faults of the Qinling, while the southernboundary is located in Wanyuan, its north-south width is about120km. Through the studyarea aeromagnetic anomaly field and the distribution of the crystalline basement burial depth, show that Ordos Basin and Sichuan Basin have a good integrated features, and theOrdos Basin aeromagnetic anomalies were protruding southward trend, the Sichuan Basinaeromagnetic anomalies are presented northward bulge, these marks the North Chinacraton and the Yangtze craton two blocks opposite migrate trajectory. Qinling-Dabaorogenic belt crystalline basement is shallower than its north and south sides Ordos Basinand Sichuan Basin, combined with the gravitational field and seismic wave fieldcharacteristics described that the North China Craton migrate to the south with high angle,and the Yangtze Craton migrate to the north with low angle.This series research about magnetic field and magnetic structures provide animportant basis for the further understanding the upper crust properties, structural pattern,deep kinematics, kinetics perspective, deep understanding and the potential resources ofthe study area. At the same time we analyze the sedimentary, crystalline basement andvarious types of fracture distribution through artificial earthquakes deep exploration,pointed that the sedimentary is very uneven, Qinling and Daba derived from the sameorogenic Keegan, analyzed the interaction coupling response and deep dynamic processbetween the North China craton, Qinling-Daba orogenic belt and the Yangtze cratonthrough fracture distributions and crystalline changing, These will surely to give a moreprofound understanding about the Qinling-Daba orogenic belt magnetic structure, the wavefield characteristics, its deep process and the crystalline base distribution, furtherdetermining the kinematics and dynamics trajectories of the Qinling-Daba orogenic belt. |
