大兴安岭区古生代优地槽褶皱带质疑  

DAXING'ANLING REGION MAY NOT BELONG TO A PALAEOZOIC EUGEOSYNCLINAL FOLD BELT

作　　者：南润善[1] 

机构地区：[1]沈阳地质矿产研究所,辽宁沈阳110032

出　　处：《辽宁地质》2000年第1期47-50,共4页

基　　金：中国地质科学院<中国主要造山带地层系统的建立及疑难地层问题的研究>项目

摘　　要：根据火山岩、绿片岩发育等特征 ,中国著名的地质学家认为 ,大兴安区是古生代优地槽褶皱带。最近 ,笔者识别出其台型沉积岩建造 ,如石英砂岩、含磷岩系、红层、石灰岩含燧石结核和夹有燧石条带等。按大地构造学理论 ,台区沉积岩建造与槽区火山岩系不能共生。为此 ,置于古生界中的大部分火山岩不该属古生界 ,而应属中生界。额尔古纳河组和佳疙疸组为整合接触 ,都夹有绿片岩 ,皆属元古宇。本区古生代地层是盖层 ,元古宙地层为结晶基底。因此 ,该区为地块 ,而不是古生代优地槽褶皱带。The famous Chinese geologists all consider that the Daxing'anling region belonged to a Palaeozoic eugeosynclinal fold belt, because there are volcanic rocks and greenschist Recently,the author found some platformal sedimentary formations,such as quartzose sandstone,rock system containing phospate concretion,red bed,limestone with flint nodule and flint band in those strata This paper believes that the greenschist must belong to the Proterozoic eonothem but it can′t belong to the Lower Palaeozoic erathem because the Jiagedan and Ergunahe formations with greenschist are relation of conformable contact and the Lower Cambrian Suzhong formation found later is made from sedimentary rocks in the shallow sea face and it isn't made from metamorphic rocks According to the geotectonic theory,the platformal formations must on no acount coexist with the geosynclinal volcanic rock system The present region develops the platformal formations made from sedimentary rocks Therefore,the volcanic rocks placed in the Palaeozoic strata couldn't belong to the Palaeozoic erathem but they might belong to the Mesozoic erathem because The Daxing'anling region develops the Mesozoic volcanic rocks and the Mesozoic geotectonic movement that breaks the natural sequence of the Palaeozoic strata and impels Mesozoic volcanic rock system contacting the Palaeozoic strata In Daxing'anling region,the Palaeozoic erathem is a cover and the Proterozoic eonothem is acrystallization basement These double layer structures are important characteristics of platformal region Therefore, Daxing'anling region is a block,but not a Palaeozoic eugeosynclinal fold belt

关 键 词：古生代 大兴安区 地块 优地槽 褶皱带 

分 类 号：P544[天文地球—构造地质学] P542.2[天文地球—地质学]