The Earth Orbital Parameters Analyses For Hydrogenous Elements Of Nenjiang Formation In Songliao Basin

The earth orbital cycle is the periodic change of the orbital parameters when the revolution and rotation of the earth occur.It is the common process in ancient sedimentary record.The sedimentary rhythm is controlled by the cyclical changes of the earth's orbital parameters.The biosphere,hydrosphere and atmosphere of the earth surface system are affected by the earth's orbital cycle.Not only they have their own performance of rhythmicity,but also have strongly affects to the deposition through the feedback system.The Cretaceous was a typical geological history stage of the extreme greenhouse climate period.Especially in the late cretaceous period,hundreds of geological events were outbreak.But the research for the Cretaceous period mainly focus on the marine layers.In order to better understand the geological history of the Cretaceous period,the Songke 2nd well(SKII)was drilled in northeast of China.The main purpose of this study is to explore the Milankovitch cycles in hydrogenous elements of the Nenjiang formation in Songliao Basin and reveal the responses mechanism between the Milankovitch cycles and corresponding element.This can help us deduce the ancient climate cyclical change of the period of Nenjiang formation in Songliao Basin.There are three kinds of elements that will be discussed here.(1)redox-sensitive elements: Fe/Ti,S;(2)the burial of TOC;(3)salinity-sensitive elements: Sr/Ba.The adopted core which total length is163m(1086m-1249m)came from two members of the Nenjiang formation: member 1and member 2.Most of the cores are preserved relatively continuously.And the Milankovitch cycles are well identified in Fe/Ti,S,TOC and Sr/Ba respectively through the implement of the R.Although the signal of some element is not continuous and obvious,it has no influence to the overall record of characteristics.As a good oxidant and reducing agent,the interaction also consist in the Fe,S and TOC.Finally,we found that the factors which have effect on the lacustrine environment of Songliao Basin is the precession which is modulated by the eccentricity simultaneously.Due to the important influence of the Milankovitch cycles with affecting the amount of the solar radiation received by the earth,and the change ofprecession regulate the perihelion and aphelion location of the earth,the paleo-environment of lacustrine and the paleoclimate would appear corresponding cyclic changes of humid and arid.