遗迹化石及其对古环境分析的意义

近二十多年来遗迹化石学在国际上进展显著,日益受到地质学家的重视,出版了许多有价值的学术论文和专著,包括一些重要的原理和研究成果。遗迹化石不仅是作为古生物学的一个部分,研究地球上生物活动和进化的证据;遗迹化石也是生物成因的沉积构造,可以用来分析岩相形成条件和解释沉积环境,生物扰动既可以对沉积物进行改造和破坏,也可以对沉积物进行建造,应当是沉积学研究当中不可忽视的一个部分。本文着重介绍遗迹化石对古代沉积环境分析的重要意义。

TRACE FOSSILS AND THEIR SIGNIFICANCE FOR INTERPRETATION OF THE PALEOENVIRONMENTS

Since the past decade increasing interest has been taken in the use of trace fos-sits as paleoecological indicators, the influence of bioturbation upon sedimentaryprocesses and the nature interaction within the soft-bottom community. This paperbegins with a presentationof the behavioral characteristics and classification of tracefossils，and then a discussion of their use in paleoenviron m ental reconstruction.Trace fossils map be used to distingush marine from non-marine and transitionaldeposits. The most successful application of ichnologp to sedimentology is in theaspect of facies analyses and paleobathymetric zonation of marine deposits. Tracefossils can furnish valuable information concerning the general depositional proces-ses，the relative rate of deposition and erosion and the characteristics of current,bottom matter. The trace fossils assemblage of a deposit can be compared with bodyfossils and lithologicaI evidence so as to reconstruct a m odel of the ancient environ-ments.