Characteristics And Tectonic Significance Of Regional Potential Field Beneath Sulu High?pressure & Ultra?high?pressure Metamorphic Belt

The Sulu Ultra-high-pressure (UHP) metamorphic terrane is considered the world's largest known high pressure metamorphic belt, the UHP metamorphic belt formed by subduction exhumation mechanism of the continental tectonic movement of the hot spots. The Earth is insight into the Earth's internal structure and state of the lithosphere the formation and evolutionary history of a powerful tool. Through the processing and interpretation of the area regional gravity and magnetic data, an area tectonic framework, which owns the scientific value.In the high pressure metamorphism evolution of the study, ultrahigh pressure metamorphic rocks of the original rock and former UHP metamorphic event study has been the weak link. To explore HP-UHP metamorphic terrane formation evolution history necessary former HP-UHP metamorphic event historical (including metamorphic basement rocks formation and tectonic environment, main tectonic event time limits issues) well EHV metamorphism Impact and Constraint studied. Currently on Sulu-UHP metamorphic belt tectonic studies, mainly in the establishment of reentrant structural framework, diving structure and rheology remodeling, subduction and exhumation of the event time, and the subduction and exhumation mechanism and exploration.Sulu UHPM belt world research Lu a continent collision subduction and shell mantle interaction best geological place continental dynamics research base. To understand the high pressure metamorphic belt of rock formation, exhumation and the corresponding dynamic process that requires understanding of the crust and upper mantle. Even though there are some Sulu ultrahigh pressure, high-pressure metamorphic belt region geophysical research results to be reported, but its explanatory depth, especially on the regional gravity and magnetic field to conduct a comprehensive in-depth processing and interpretation have not. Therefore, in the previous already have, based on the full use of the area geology, CCSD data, will be the regional gravity and magnetic field characteristics and tectonic tectonic framework of relations linked to in-depth study is urgently needed.This study combined with the national 973 project on "continental plate convergence boundary deep material physical state of high temperature and pressure experimental study," the son of issues, "continental plate convergence boundary in deep rock magnetic structure" (2003CB716506) the continuation of the research needs of the election of this topic;This study to to Sulu hyperbaric UHP metamorphic belt regional gravity magnetic features research main line, ago people rich tectonic geological, petrology and Geochemistry and seismological research based, study area important Geological Problems-UHPM rock deep subduction and exhumation dynamics target to few specific geological problems basement properties (lithology, tectonic with geometry), important tectonic boundary (North and Yangtze platform, deep subduction and Tanlu breakage), Moho surface and magnetic next interface and crust nature study bridge explore UHPM process regional gravity magnetic response establish multi scale weight magnetic Structure and crust and lithosphere structure relations for Lu Lu collision dimensional structure provide evidence.The geology, geophysics, geochemistry, petrology, mathematical and physical modeling, signal processing and other issues combined to solve related problems; this study, the necessary basic theory related to geology, classical physics, computational mathematics, signal processing and other disciplines. To the known geological, geophysical prior information as constraints on regional gravity and magnetic field for geophysical inverse calculation can be carried out from qualitative to quantitative process of interpretation, highlighting the regional crustal properties of spatial distribution, identification of the study area important geological, establish important geophysical tectonic characteristic, deduced several tectonic geological model matching analysis, proves crust tectonic framework relations understanding.Main study includes:(1) re magnetic data processing and inversion research, focus multi scale weight magnetic Separation and Characteristics; (2) research District several specific Geology: basement properties (lithology, tectonic with geometry) important tectonic boundary (the North China platform, the Yangtze platform, deep diving and the Tan-Lu fault, etc.), Moho surface and magnetic properties of the interface under the nature and lower crust nature of research as a bridge to explore the UHP process of regional gravity and magnetic response; (3) establish multi scale weight magnetic Structure and crust and lithosphere structure relationship, propose crustal tectonic framework relationship model.By analyzing regional aeromagnetic anomaly characteristics and obtained UHPM belt crustal magnetic structure. (1) study area Magnetic petrology characteristics. General laws as:acidic rock like granite granodiorite and granitic gneiss area showed low magnetic characteristic; basic ultrabasic rock mostly distribution small, caused magnetic anomaly obvious; basement deep metamorphism rocks show a strong magnetic anomaly. (2) According to the different scale magnetic anomalies in the study area were constructed partition. Total divided out China craton, Yangtze craton and Sulu orogen three level tectonic units Tanlu fault, Luxi Taiwan Lung, Xuhuai fault uplift, Subei Jiaonan terrane and Subei broken Au five level tectonic units. These results with the regional geological structure is consistent. (2) The area of deep obvious North West to the distribution of large-scale geological body, from Shandong-Taiwan Lung across the fault zone, by Jiaonan sunshine into the Yellow Sea. Magnetic top interface depth of about 20km, at the Tan-Lu fault west of the somewhat shallow, east a little deep, roughly reflecting the western side of the relative uplift, east of relatively concave features. And Luxi exposed Taishan Group metamorphic magnetic considerable, suggesting that the magnetic body is a North China craton Archean metamorphic rocks, revealed lower crust North China Craton material continuously extends to the North, and although Northern Upper Crust is the Yangtze craton. (3) analysis aeromagnetic Spatial Variation found Sulu different wavelengths magnetic Anomaly Sources spatial overpass structure characteristics. Top-down order:upper north east-based middle-wavelength magnetic anomaly field source, the middle of north west-based medium and long-wavelength magnetic anomaly field source, following the north east-based long-wavelength magnetic anomaly field source. This "overpass" type of space magnetic structure may be 2 kt through collision and detachment results, reflecting the Yangtze and North China craton collision dynamics model.