旋回地层学和天文年代学及其在中生代的研究现状

The current status of cyclostratigraphy and astrochronology in the Mesozoic

地质年代的精确确定是我们认识地球演化历史和过程的关键,而如何提高地质年代的精度却一直是个尚待解决的科学难题。最近30年多年来,基于古气候学研究的天文旋回理论获得了普遍认可和广泛应用,尤其是成功应用于天文地质年代校准中。这种数字定年方法是通过天文调谐获得连续的高分辨率的地质年代,是对传统地质定年方法如古生物、古地磁以及放射性同位素测年方法的一次革新。最新的国际地质年表The Geologic Time Scale 2012(简称GTS2012)中经过天文校准的地质年代已近100%覆盖了新生代,而中生代的天文年代校准还存在着很大挑战。目前应用稳定的405ka的偏心率长周期对中生代地层进行天文地质年代校准,是国际地质年表从GTS2004到GTS2012的一个最大改进。文中将主要介绍天文旋回的基础理论和其在中生代的应用及其研究现状。

Accurately determining the geological time is the key to our understanding the Earth＇s evolutionary history and geologic processes. And how to improve the accuracy of geological time has always been a scientific problem to be solved. The astronomical theory based on the paleoelimate changes has been generally accepted and widely used over the past thirty years. Especially it was success^ully applied to the astronomical calibration of the geology time scale. This digital dating method is to obtain a continued high-resolution geological time by astronomical tuning, which is an innovation of the traditional geological dating methods, such as paleontology, paleomagnetism and radioisotope dating methods. An absolute astronomical time scale （ATS） has been calibrated most of the Cenozoic time in the latest international geological chronology of The Geologic Time Scale 2012 （GTS2012）, however, there is still a challenge for astronomical calibrating the Mesozoic time. Currently, the application of the stable 405 ka long eccentricity period to calibrate the Mesozoic Geological time scale is the biggest improvement of the geology time scale from GTS2004 to GTS2012. This paper introduces the basic theory of astronomical cycles and its current application status in the Mesozoic.