豫西鲁山中元古界云梦山组微生物成因沉积构造发育特征及古环境意义

Characteristics of Microbially Induced Sedimentary Structures and Their Paleoenvironmental Significance from the Mesoproterozoic Yunmengshan Formation in Lushan Area, Western Henan

前寒武纪的生物界是以微生物为主导的,微生物所引起的生物沉积构造的研究一直受到地质学家重视。以往的研究多集中在碳酸盐岩地层,近年来以发育在碎屑岩地层为主的微生物成因沉积构造(MISS)也成为地学界的研究热点之一。豫西鲁山地区云梦山组隶属于中元古界汝阳群,在构造古地理上属于华北地台南缘,主要为一套陆源碎屑岩沉积,其层面发育了大量的MISS,且类型多样。MISS类型的分布特征对精细环境有良好的指示作用;MISS的大量发育表明了当时微生物群落的繁盛,揭示了当时的微生物群落对古环境具有的强大改造功能。

The Precambrian biosphere was dominated by microorganisms.The study of biosedimentary structures caused by such microorganisms has always been paid great attention by geologists;however,previous studies have tended to be mainly focused on carbonate strata,and in recent years showed a particular interest in Microbially In⁃duced Sedimentary Structures(MISS),which are mainly developed in clastic strata.The Yunmengshan Formation in the Lushan area consists mainly of a set of Mesoproterozoic clastic strata.At the base of the Ruyang Group,the forma⁃tion lies at the southern margin of the North China Platform.MISS are especially abundant in the bedding surface,and display a large range of morphologies.Various types of MISS distribution indicate the paleoenvironment in detail.The extensive development of MISS in the Yunmengshan Formation reveals a flourishing microbial community at that time,which provides strong evidence for reconstructing the ancient environment.