中国北方埃迪卡拉纪冰碛岩及冰川作用  

Ediacaran diamictites and glaciation in northern China

作　　者：柳永清[1] 旷红伟[1] 陈骁帅 王玉冲 江小均[3] 许欢 祁柯宁 彭楠[1] LIU Yongqing;KUANG Hongwei;CHEN Xiaoshuai;WANG Yuchong;JIANG Xiaojun;XU Huan;QI Kening;PENG Nan(Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;College of Geosciences and Surveying Engineering,China University of Mining and Technology,Beijing 100083,China;Kunmimg Department of Earth Sciences,Faculty of Land Resource Engineering,Kunming University of Science and Technology,Kunming,Yunnan 650093,China;Yunnan Key Laboratory of Earth System Science,Yunnan University,Kunming,Yunnan 650500,China;School of Resources and Environmental Engineering,Hefei University of Technology,Hefei,Anhui 230009,China)

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国矿业大学(北京),北京100083 [3]昆明理工大学,云南昆明650093 [4]云南大学,云南昆明650500 [5]合肥工业大学,安徽合肥230009

出　　处：《地质学报》2023年第12期3984-4005,共22页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42072135);中国地质调查项目(编号DD20221649)联合资助的成果。

摘　　要：中国北方从东到西绵延3000 km范围上的华北克拉通、塔里木克拉通及其中间微地块上都保存有埃迪卡拉纪冰川沉积记录,但有关它的年代学、冰川规模、古地理重建和大地构造背景等存有争论。本文基于中国北方埃迪卡拉纪冰碛岩空间分布、地层与沉积层序,沉积环境与沉积相等,结合以往国内外文献,系统分析了埃迪卡拉纪冰川上述有关问题。研究揭示,埃迪卡拉纪时期,国内外应存在年轻于(Gaskiers)580 Ma的冰期;中国北方埃迪卡拉纪冰川时限约562.5~551 Ma,堆积了冰下、冰缘和冰前沉积相(物),构成垂向上(由下至上)从冰下至冰前与海相冰碛物沉积层序,符合大陆冰川(盖)沉积响应样式;此外,国内外埃迪卡拉纪冰碛岩及冰川剥蚀地貌均十分发育;部分冰碛岩之上还可见盖帽白云岩,并呈现与成冰纪盖帽白云岩类似的沉积构造,但彼此碳同位素剖面却不尽相同;本研究推测,埃迪卡拉纪时期,原特提斯洋及周缘大陆(群)可能普遍存在至少是洲际性大陆冰盖,甚至是全球性的冰期。研究认为,埃迪卡拉纪时期的亚洲陆块群应与冈瓦纳大陆缺乏构造亲缘性的若干重要证据。本文研究结果在埃迪卡拉纪大陆及其古地理重建和大地构造背景恢复方面具有重要科学意义。The Ediacaran glacial deposits are developed in the North China Craton,Tarim Craton and themicroblocks among them,where they can extend for 3000 km from east to west.However,thechronology,scale of glaciation,paleogeographic reconstruction and tectonic setting are still controversial.Based on the spatial distribution,stratigraphy and sedimentary sequence,sedimentary environment andsedimentary facies of the Ediacaran diamictites in northern China,combined with previous literatures athome and abroad,the above issues related to Ediacaran glaciations are systematically analyzed.This paperrevealed that during the Ediacaran,there should have been a glaciation of younger than 580 Ma(Gaskiers)all over the world.The age constraints of the Ediacaran glaciations in northern China were placed between562.5 Ma and 551 Ma,and the subglacial,periglacial,and proglacial sedimentary facies can be identified;these form the diamictite from subglacial to proglacial,followed by normal marine sedimentary sequencesvertically(in ascending order),in line with the sedimentary response pattern of continental glacier(icesheet).The Ediacaran diamictites and glacial erosional forms are widespread distributed globally,and thecap dolostones can be developed above the diamictites,exhibiting sedimentary structures similar to theCryogenian cap dolostones,but the carbon isotope characteristics of them are not the same.This paperspeculates that the Proto-Tethys Ocean and its surrounding continents may have developed continental icesheets during the Ediacaran,but there was no affinity between the Asian blocks and the Gondwanasupercontinent.The results provide geological evidences for the global paleogeographic reconstruction andtectonic setting restore of the Ediacaran period.

关 键 词：埃迪卡拉纪 中国北方 冰碛岩 沉积相 大陆冰川(盖) 洲际性 时限 

分 类 号：P343.6[天文地球—水文科学] P535[天文地球—地球物理学]