前寒武纪旋回地层学研究的进展与挑战

PROGRESS AND CHALLENGES IN PRECAMBRIAN CYCLOSTRATIGRAPHY RESEARCH

前寒武纪占据地质历史绝大部分时期,在大气成分、古气候、生命和超大陆聚散等方面表现出不同时间尺度的变化和演化。近年来人们在全球范围内前寒武纪地层中识别出大量可靠的米兰科维奇旋回记录。借助各类沉积旋回分析,有望建立地球早期演化高分辨率年代框架,获取行星轨道相互作用资料并重建天体动力史。本文在简要回顾旋回地层学理论方法的基础上,通过前寒武纪旋回地层学研究的主要范例,分析了原始气候替代性指标、重建天体动力模型、复杂气候模型和古地理不确定性等前寒武纪旋回地层学研究的关键问题和主要挑战,尝试性地提出了这些问题的解决思路。

Occupying the larger part of the geologic history,Precambrian witnessed numerous dramatic changes and evolutions of the atmospheric composition,paleoclimate,early biosphere and geography in various timescale.Our knowledge of Precambrian Milankovitch cycle,climate proxy indexes,earth-moon system evolution,extreme climate change and paleogeography variation has largely increased during the past decades.A high resolution chronological framework for early earth evolution and the interaction of planetary orbit and reconstruction of astrodynamics history can be established via identifying and using the sedimentary cycles driven by the orbital force.This paper gives a brief introduction of the basic theory,and through analyzing the representative research cases put forward the key problems and their solutions in the Precambrian cyclostratigraphy.