贵州东南区埃迪卡拉系层序地层格架  

Sequence-Stratigraphic Framework for the Ediacaran in the Southeastern Part of Guizhou Province

作　　者：张海[1,2] 甘凤伟[3] 魏宁[1,2] 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]中国地质大学地球科学与资源学院,北京100083 [3]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550002

出　　处：《现代地质》2010年第2期221-227,共7页Geoscience

基　　金：中国石化科技工程重点项目(QZ-2005-06)

摘　　要：贵州地区的埃迪卡拉系由陡山沱组和灯影组构成,其中陡山沱组以硅质岩为主,灯影组以泥晶白云岩为特征。选取典型剖面进行层序划分,通过空间追索和对比,建立研究区埃迪卡拉系层序地层格架。层序地层格架的建立表明:从陡山沱组到灯影组构成一个总体向上变浅的沉积序列,该序列组成一个二级构造层序,并进一步划分为5个三级层序。二级层序及其所包含三级层序具有相似的相序组构,体现出"旋回含旋回"的特征。从浅水台地区到深水盆地区,灯影组白云岩不存在白云岩相变为灰岩的现象,可能从另一个角度表明这套白云岩就像陡山沱组底部的"帽白云岩"那样是原生白云石沉淀作用的产物,并且可能反映了"帽白云岩"所指示的前寒武纪晚期"极端温室效应"的延续。Ediacaran system in Guizhou Province is made up of the Doushantuo Formation and the Dengying Formation,in which the Doushantuo Formation is mainly composed of siliceous rock,and the Dengying Formation is mainly marked by micritic dolomite.On the basis of sequence-stratigraphic division for some typical sections,sequence-stratigraphic framework for the Ediacaran system in the southeastern part of Guizhou Province can be established.The stratigraphic succession from the Doushantuo Formation to the Dengying Formation constitute an upward shoaling sedimentary succession,and this succession make up one second-order sequence that can be further divided into 5 third-order sequence.Importantly,the similarity of succession of sedimentary facies between the second-order and third-order sequences reflects the basic feature,i.e.＂cycle within cycle＂.Furthermore,an important phenomenon that dolomites in shallow platform do not change into limestone in deep-water basin within the Dengying Formation reflects an important sedimentary feature,i.e.this set of dolomits may be resulted from primary precipitation that is same as the formation of ＂cap dolomite＂ in the bottom of the Doushantuo Formation and may represent the continuation of ＂the extreme greenhouse effect＂ in the Late Precambrian.

关 键 词：层序地层学 层序地层格架 埃迪卡拉系 贵州东南区 

分 类 号：P534.31[天文地球—古生物学与地层学]