Cyclostratigraphy And The Deposition Rate Analysis Of The Cenozoic Strata In The Southwestern Margin Of The Qaidam Basin

This paper introduces the basic principle of cyclostratigraphy analysis.Guided by the theory,we had studied all kinds of methods in power spectrum analysis and time-frequency analysis to use geophysical well logging data to identify the Milankovitch cycle.At the same time,we also had completed the numerical simulation and some application researches of real data about the method of deposition rate calculation to use sliding window spectrum analysis.Through the study,we had analysed the response mode of stratum and the characteristics of the high frequency cycle,verified the practicality of the method and summarized the applicability of this method.On the basis of this,we had writed programs and integrated all modules for various main mathematical methods to developed a cyclostratigraphy analysis and data processing software system,which have friendly interface,simple operation and complete function.Later,we carried out some related researches about cyclostratigra-phy of a complete Cenozoic strata in the southwestern margin of the Qaidam Basin through natural gamma logging data by use of my software.Through the study,we had verified the existence of the Milankovich cycle in each strata,identified the sedimenta-ry discontinuity and Event deposits in the strata,used the Milankovich cycle curves to estimate the deposition time of the strata of upper xiaganchaigou formation and shangganchaigou formation,and the time of duration is about 4.4 1Ma and 3.3 Ma,resp-ectively.Through the actual data application,we had summarized a set of effective processing flows and experiences about the cycle analysis and the deposition rate cal-culation in this areas and obtained the high resolution change trend of deposition rate in this area.In the end,we had compared and analyzed the deposition rate data combined with the previous researches to investigate the response of the totectonic uplift of East Kunlun Mountains orogenic belt in the northeastern of the Qinghai Tibet Plateau and climate change events in this area through the evolution trend of the deposition rate.Through the study,we had speculated that there may be at least three stages of tectonic uplift in East Kunlun Mountains since the Eocene.The time of uplift correspond to about 38Ma before,about 30-15Ma and about 8Ma.Each stage of the tectonic uplift events is not confined to the East Kunlun Mountains area,there are also some clues in other areas of the Qinghai Tibet Plateau,reflecting its universality.In addition,the deposition rate appeared again increased significantly since about 2.65Ma,this phenomenon may be due to the climate change,which had influenced the erosion rate,these questions need to further study.