Distributional Characteristics And Relationship With Geotectonics About Crust Physical Property In Northeast Of China

In the theory study of solid geophysics science, the large scale cracking andmineralizing that are caused by the deep dynamic process of crust and theinteraction between crust, manthle, aureole and strata are still leading edgescientific problems, and the problems are not yet solved. The exchange of deepmatter and energy with deep dynamic process is the core of mineralizingmechanism and deep physics – chemistry process in northeast of China. The papercalculates the physical property distribution of region of interest, and gets a lot ofnew cognition about Songliao basin deep oil gas and geotectonics characteristics ofthe northeast of China through analyzing the distribution. The cognition belongs topart of geotectonics theory about northeast Asia, and there is a certain applied cost. Aiming at the crust of in northeast of China, the paper collects and arrangesthe all sorts of geophysics data incluing nature earthquake, near normal reflection,artificial wide-angle earthquake and gravitation. This thesis mainly studies thedistribution of P wave in Songliao basin, and the paper newly discusses thedivision of tectonic element. the paper analyzes the distributional characteristics ofvelocity about the northeast of China, and then get the distributional curves of Pwave velocity within crust range in region of interest through a new P and S wavevelocity relationship. On the basis of the P wave distribution, the paper obtains thenew characteristics about Moho depth and Q value within crust range in entirenortheast region of China. By using ray tracing technology under geotectonicsmodels, the paper detailedly discusses the interior structure of transition zoneabout Moho. According to this study, the paper brings forward the new cognitionabout fine structure of crust in entire northeast region of Chia. All cognitionsprovide the new references for the geotectonics theory.The model structures of geotectonics models are usually easy, so the classicalray tracing methods can always trace the precise forward results, but the range ofgeotectonics model is very large, the forward data size is so big that the classicalray tracing under seismic prospecting model need plenty of time to calculate, theresult usually can be gotten. Aiming at geotectonics models, the paper applies anew ray tracing method that fits for 2D geotectonics models. Through calculatingtheory model, the method can accurately and quickly get the trace of seismic ray.Then the paper analyzes the recognition question about thin bed under basin modeland geotectonics model by using the new ray tracing method. Under basin medel,the thickness of thin bed h is the relationship about theory wavelet frequency f andthin bed velocity v: . And that under geotectonics medel, therecognition of thin bed is more complex, the thickness is affected by executionconditions, collection method and processing procedures besides seismic waveletand velocity.h ≥0.35v/fThe thesis study the velocity structure in Songliao basin, through arrangingthree near normal reflection profiles data and three long artificial seismic profilesdata, the paper sketches the the distrition relation of P wave velocity withinSongliao basin range. After qualitatively and quantificationally analyzing the Pwave velocity under different depth, the divitions of geological structure are mostcorresponding to the changement of P wave velocity. According to the results, wepresent the new geological structure cognition, which provede the reliable7reference for the direction of hydrocarbon prospecting.In the MANZHOULI-SUIFENHE geoscience transect, the paper analyzes thevelocity distribution characteristics about the P wave velocity of artificialwide-angle earthquake and S wave velocity of nature earthquake. By generalizingtwo data, the paper gets the velocity ratio of P wave and S wave in the geosciencetransect. The ratio provides the basic information for calculating P wave velocitywithin the entire northeast region of China. Based on the trend of geologicalstructure in northeast of China, the paper puts forward an extrapolationrelationship of velocity. By using the velocity ratio of P wave and S wave in theMANZHOULI-SUIFENHE geoscience transect and S wave velocity in the regionof interest, the paper finally obtains the P wave velocity distribution in northeast ofChina.The paper chooses the contour line whose value is 8.05km/s of P wavevelocity in northeast of China to be the botton of Moho, and describe the newdepth distribution in detail. By comparing with the Moho of nature earthquake Swave velocity and of gravity field, the new data can more detailedly depict theshape of Moho. the paper also studies the interior structure of Moho transitionzone through the ray tracing method under geotectonics model. The results showthat there are structures in the Moho transition zone, the number of earthquakephases are relative to the strata of transition zone and the inhomogeneity of Mohothickness. In essence Moho is a fluctuant transition zone with big wave impedancedifference and kinds of lithologies.In the study of strata absorption and attenuation, quality factor Q is the one ofmain parameters that can weigh the absorption and attenuation. There are too manyfactors to affect Q value, so it is very difficult to establish the relationship betweenQ values and all fators, field actual measurement is a rational method. The thesisestablishes the new relationship of crust and mantle media between Q value and Pwave velocity on the base of the relationship between the two values under basinmode. According to the distribution characteristics of P wave velocity in region ofinterest, the paper gets the distribution relation of Q value that represents theregulation of absorption and attenuation in northeast of China.The study analyzes the geology-geophysics characteristics in whole northeastof China by the numbers, we bring forward the oil gas prospect area according tothe six profiles in Songliao basin. Through the relationship of thirty-six P wavevelocities and Q value, we analyze the distribution characteristics of middle andupper crust. We study the area of the granite band of the Great Xingan Mountainsin northeast of China, and then discuss the attenuation mechanism of lithosphereand crust.The paper describes the physical property parameters about crust in northeastof China by establishing the relationship of physical property parameters, somenew acknowledge are obtained. It is very significative of the results to the theoryof deep oil gas potentiality and the establishment of resources assessment system.The information provide some science reference for the source regionalizationabout sustainable development of oil gas resources and strategy system of nationaloil gas resource in northeast of China.