Erosion Thickness Restoration And Palaeotectonics Analysis In TaBei And TaZhong Area

In recent years， the Tarim Basin Silurian received extensive attention， inwhich the exploration degree of TaZhong and TaBei area is the highest， for theanalysis of characteristics of Silurian ancient tectonic，the denudation recovery isvery important. The paperis guidanced by the seismic stratigraphy，sedimentology，structural geology， comprehensive seismic and drilling data， using mudstoneacoustic time difference method and seismic method combining calculate SilurianYimugantawu formation， Tataaiertage formation and the Kepingtage of the Silurianin TaBei and TaZhong area strata denudation then analyzes it stectonic characteristics.The actual work to restore denuded thickness in the use of Mudstone acoustictime difference method， the specific process of operation methods are improved，improvements include:(1) from the original manual reading mudstone acoustic traveltime to the computer filter，greatly speed up the work efficiency;(2)the originalmethod of the surface acoustic travel time is not preciseness. According to Quaternaryor Neogene mudstone sonic value for the surface get each well point value acoustictravel time and calculating the average in the same tectonic background.In the seismic method，T60as a major unconformity，T61， T62， T63，T70ofSilurian interface with angular unconformity contact with underlying，and make theSilurian lack of large stratum in TaBei and Tazhong area.Using the seismic tendencyepitaxy recover each ancient formation interface to get the erosion thickness.By combining the two methods obtain the rules of distribution of erosionthickness，in TaBei and Tazhong area.Results show that: the horizontal Tabei areaaffected by the North uplift of Tarim Basin， Silurian erosion is up to1500meters;Tazhong area affected by the central uplift zone，sedimentary thickness has beenmodest， Erosion is only500meters. Longitudinal the erosion of Kepingtage、Tataaiertage formation is larger， later suffered Denudation Quantity is bigger， butuntil Yimugantawu formation sedimentary basin is smaller，erosion of Yimugantawuformation are not big in TaBei and TaZhong area.By recovering the Silurian thickness of each layer to get the Silurian paleostratathickness distribution of each formation， maximum thickness is up to3000meters，results show that effecting by the North-South compressional stress make sedimentary center process of the Silurian from the east to the West.