METHODS OF ERODED STRATA THICKNESS RESTORATION IN SEDIMENTARY BASINS

Multi-type restoration methods to estimate the thickness of eroded sedimentary rocks can be categorized into four types:geothermal,geological,geophysical and geochemical methods based on paleothermal index,stratigraphical or sedimentary principles,logging or seismic data and diffussion or accumulation theory,respectively.Every type has its own effective conditions or limits in application to estimate the eroded thickness of rocks.In practical application,it should make sure to select the most effective methods or their combinations according to development,structural evolution and unconformity surface of sedimentary basins.It was considered by integrated analysis that paleo-temperature vitrinite reflectence(R_o) and paleo-temperature gradiends of apatite fission-track(AFT) are primary choices under conditions of strata reliabilities in combination with basic condition that lower tectonic layer underwent higher paleo-temperature than upper sequence.As for Mesozoic-Cenozoic sedimentary basins,We can choose porosity methods and/or acoustic travel interval time in combination with paleo-temperature gradients to carry out restoration of eroded thickness.And for multicycle superimposed basins since Phanerozoic,we should carefully analyse sedimentary features and evolution history of basins,qualitatively constraint ranges of eroded thickness using stratigraphic correlation methods then quantitatively calculate using geothermal data and/or sedimentary wave analysis.