关键词: 古生物钟, 地月系统, 撞击事件, 引潮力力矩

Abstract: Contrasting the curve derived from the theory of the evolution of the earth-moon system with the ones based on the analysis of the shelly fossils distributed over the period from Ordovician to modern time reveals great discrepancy. Two turning points exist in the curves based on data analysis. The times of these two points coincident with the occurrence of the largest two extinctions in Permian-Triassic and Cretaceous-Tertiary, which is extensively believed to be results of the extraterrestrial impact. Further analysis on the sedimentary facies of these two boundaries throughout the world, which are previously thought of as a world-wide regression provide us more eloquent records. The mutation of interaction and the phase lag between the earth and the moon caused by extraterrestrial impact, from which the obvious mutation of the torque of the tidal force resulted, give us a reasonable interpretation on these two turning points.

Key words: paleontological clock, earth-moon system, extraterrestrial impact, tidal force torque