年代古地理学: 理论与实践*

古地理学研究和探讨的是地质历史时期的地表环境,是构造—环境(气候)—物质相互作用的产物。传统的古地理学及相应的构造古地理、生物古地理学等对大地构造演化及古大陆重建、油气勘探等起到了重要的作用。随着地球演化的深入研究,在多层圈的相互作用,特别是古气候、古环境等研究基础上,需要有机地把地表环境和构造环境相结合,并且综合考虑深层及浅层地质过程对古地理格局的形成和演化的制约。在传统的古地理学基础上,提出一个新的学科——年代古地理学,用以研究和探讨地质历史时期的地表过程。该学科是精细的同位素年代格架下的不同动力学—运动学—物质迁移—环境变迁形成古地理的研究,或者物质—力学—环境(气候)相互作用下的古地理格局的研究。旨在研究和探讨地表过程,亦即形成地表环境的过程,强调同一时间的多元性、不同空间的差异性和不同尺度的穿时性。文中以近年来研究的台湾、扬子及华北克拉通等地区的精细时间尺度下的古地理环境为例,进一步剖析年代古地理学对于重新理解和认识古构造格局演化的重要性。

Chrono-palaeogeography: theory and practice

The palaeogeography is to study and understand the earth-surface environment in the geological histories,and it is a product of tectonics-environment(climate)-sedimentation interaction and reaction. The traditional palaeogeography and related tectono-palaeogeography,biopalaeogeography and other subjects have given great contributions to the tectonic evolution,continental reconstruction as well oil-gas exploration and development. More and more works start to focus on the interaction of multiple-layers of the earth,especially the paleo-climate,paleo-environment studies,it's necessary to integrate the earth-surface environment and the tectonic background to reveal the influence of the deep and shallow layers geologic processes on the palaeogeographic framework formation and evolution. We propose a new concept and subject—chrono-palaeogeography to explore the earth surface process and evolution in the geological history. This subject is in a precise isotopic chronological framework to study how the different dynamics-kinematic-material transferring-environment changes shaped the palaeogeography,or how the palaeogeographic framework responded to the interactions or couplings of the materials-tectonics stress-environment(climate). Better than other subjects of the palaeogeography,this subject is for studying and understanding the earth-surface process,but not the environmental state,or the active process to form the earth-surface environment. We emphasize the multiple kinetic factors in a same time,the variation in different spaces,and the diachronous at various scales. In addition,we introduce a few case studies of high precise time constrained palaeogeographic work,such as those studies on the Chinese Taiwan,Yangtze and North China cratons,to show how chrono-palaeogeography improve reconstruction of the continent,tectonic evolution,as well oil-gas exploration.