'地时'(Earthtime)研究计划:'深时'(Deep Time)记录的定年精度与时间分辨率

摘要

地质年代的精度、准确度和分辨率的水平决定了人们在多大程度上可以回答一些关于"深时"的生态、气候、生物演化和基础地质问题.目前用于定年和对比的技术主要包括放射性同位素年代学、生物地层学、磁性地层学和旋回地层学等,但各有优缺点,甚至有时不同定年系统所获得的结果存在一些矛盾."地时"(Earhtime)研究计划就是要开展广泛的国际合作,通过整合、校正和提高地质年代学和定量地层学方法,发展出一套新的地质年代学技术,使地质年代的误差达到0.1%的水平,实现精确确定地球历史的时间及先后顺序.中国东北松辽盆地发育连续、完整的白垩系为开展高分辨率年代学研究提供了机遇,将是对"地时"研究计划在中生代陆相地层中应用的良好补充和重要贡献.%The level of achievable geological time precision, accuracy and resolution determines the nature of the deep-time ecological, climatic, biological evolution and basic geological questions for which a reasonable answer may be expected.The main dating and correlation techniques include radiometric isotopic geochronology,biostratigraphy, magnetostratigraphy and cyclostratigraphy, and each has its own advantage and disadvantage.There might have some inconsistencies between the dating results of different techniques.Earthtime is an organized, community-based, extensive international cooperation project.Its scientific objectives are to integrate,calibrate and improve high-precision geochronology and quantitative chronostratigraphy, to develop the geochronological techniques necessary to produce geological time with uncertainties approaching to 0.1％, and finally to precisely determine the ages and sequences in the deep time of Earth history.The continuous terrestrial Cretaceous developed in the Songliao Basin, northestern China, provides a unique opportunity to carry out high resolution integrated geochronological research, and its accomplishment will be an important complement and contribution of the Earthtime project applied in the Mesozoic continental records.