年代地层界线与事件地层学

ON THE CHRONOSTRATIGRAPHY AND EVENT STRATIGRAPHY

地层划分对比的目的,主要是为了指导地质生产和科研工作。据此目的,对目前盛行的“界线层型”提出了质疑。认为“界线层型”是以均变论为基础所确定的人为界线,它既不能较完全地反映地质历史发展的本来面貌,也不利于在生产、科研中推广使用。因此,作者建议采用综合研究方法,选择统一地层划分的事件界线。它不但符合地壳运动的阶段性和生物发展的规律性,而且标志明显,便于生产使用。地层中的稀有事件在地质发展史上包括生物演化及沉积环境变迁,起着巨大作用,形成的自然界线在确定地层时代和对比中具有广泛性、等时性及易辨性。在地史演化过程中一些稀有的突发事件比常见的渐进演化事件起着更加关键性的作用。而且它重视突变与渐变的结合,更强调突变和灾变,这在哲学上是正确的。因此,应积极开展事件地层学的研究,以促进我国地层学的迅速发展。

The aim of stratigraphical division and correlation are at the guidance of practical research work and mapping.Suchpurposes propose questions on the currently fluenting“boundary stratotype”.The author thinks that the“boundary strato-type”is a subjective idea based on uniformitarianism.Neither can it completely reflect the originality of the geolgical histo-ry,nor can it have important values in practical research work and mapping.Therefere,the author suggests to select eventboundaries of united stratigraphical correlation by comprehensive researches.Such boundaries are coincide with the stage ofcrust movements and the regularity of organic development,and also have remarkable characteristics which are valuablefor practical uses.The rare events recorded in strata including organic evolution and sedimentary movement changes play important rolesduring the history of geological development.The almost natural boundary is widely spread,diachronous as wll as recog-nizable.In fact,some abruptly changed rare events in the evolutionary process of geological history are more significantthan the common events in gradual evolutioary history.Moreover,the event stratigraphical boundaries are the combina-tions of abrupt and the gradual changes,with emphasis on the abrupt and catastrophic changes,which is philosophicallycorrect.Therefore,the author urges the stratigraphiers to work more actively on event stratigraphieal research,which willimprove the development of stratigraphy in China.