| Magnetisability,a measurement of the magnetization level of the substances,is considered as an important record of the Milankovitch Cycle in the stratum due to its sustainability and high resolution,despite the fact that it is under the influence of factors such as terrigenous detrital,deposit velocity,tectonic rock,and sea level eustacy.Milankovitch Cycle has been regarded as an effective research method in cyclostratigraphy in that it is characterized by relatively correctness and smaller error,and also combines the study of the age with the stratigraphic feature.This paper will give a specific introduciotn of the basic concepts,theory of Cyclostratigraphy,as well as the research progress of its application in geology,at the same time,the application principles of the signal processing in geology are presented.A systematic discussion of the mathematic identification methods of the Milankovitch Cycle in the stratum,that is,spectral analysis,is conducted in this paper,ranging from the principle introduction,sphere of application,advantages and disadvantages,to spectrum analysis methods based on Fourier transform and other algorithmic.In additional,the theory and necessity of the data processing are elaborated,together with the methods of outlier removal,tendency removal,design of filter,and statistical test of the computation.With the magnetisability data of Cenozoic stratum in Qaidam basin,the writer makes analytical calculation of power spectrum of the preprocessed data,and draw the frequency spectrum analysis diagram based on three different methods,and conducts comparison research,hence the justification of the feasibility of substitution parameter in physical geographic in Cyclostratigraphy by magnetisability,and the reliability and precision of the application of spectrum anaylysis in Cyclostratigraphy.Based on the Milankovitch cylcle which is found universal in the stratum,accurate comparison computation are conducted to the deposit velocity of the stratum. |
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