Solar insolation variation due to the gravitational perturbation among the planetary bodies in the solar system, so called the Milankovitch cycle, is widely believed as a major cause of the climatic change such as the glacial-interglacial cycles in Quaternary, and its typical frequencies are supposed to be constant during Quaternary. However, the periods of these cycles must have been largely changed following to the dynamical evolution of the earth-moon system. We have studied the relation between the frequencies of the Milankovitch cycles and the rotation rate of the earth on the basis of theoretical and computational analysis of the earth-moon system. Our conclusion is that this cyclicity which can be recorded in the sediments are mutually related well as a function of the dynamical ellipticity and the absolute age. This fact implies that we can establish the standard time scale for measuring the relative age, in other words, the lap time clock or the chronometer for decoding the whole history of the earth, by comparing the stripes in BIF and other sediments of Archean or Proterozoic with a set of theoretical Milankovitch cycle and tidal cycle frequencies.
The Japan Academy