Analysis of the astronomical periods indicated by paleo-climate records

Data sequences of both the susceptibility and particle size of loesspaleosol since the Pliocene epoch (6.2–2.5 Ma B.P.) located at Ba Jia Zui loess profile 16 km west of Xi Feng city, as well as the deep sea sediment in the Pacific Ocean are analyzed with several methods. In addition to the astronomical periods 0.1 Ma, 0.041 Ma and 0.023 Ma in the earthʹs main orbital parameters (the eccentricity, obliquity and climatic precession), more periods, namely, 0.2 Ma, 0.15 Ma, 0.08 Ma and 0.06 Ma, are derived at confidence level over 80%.Furthermore, using wavelet transform, it is found that these periods varied through the geologic time, now waxing, now waning, even disappearing. This tells us that the paleo-climate change is induced by varying paleo-environments. Recently, it has been suggested that the 0.1 Ma variation is not only related to the eccentricity of the earthʹs orbit, but probably is also closely related to the subsidence speed of interplanetary dust particles and the uplift of the Qinghai-Tibet plateau, implying that variations of the earthʹs orbital parameters are only some of the factors for the changes in the paleo-climate.