CAJ | 학술논문

距今14～16亿年的华北地区高于庄组黑色层状、结核状和透镜状燧石与叠层石的黑色硅质部分中保存着极丰富的原核和真核生物微化石.宏观藻类在该组的页岩中亦已发现.本组为评估中元古代生命状况、古环境和前显生宙生物地层提供了重要的生物信息.迄今为止在高于庄组地层中已有百余个化石种被人们认识.根据古植物和古环境的特征这些生物种类可分为三个不同的组合,即:1.颤藻和色球藻组合,出现在高于庄组一段,代表浅水藻席建造者和居住者与一些可能的外来浮游生物的种类;2.念珠藻组合,仅发生在该组的二段,还含一些底栖藻席建造者或居住者的种类;3.第四段的色球藻组合,它代表了潮间带至亚潮带的藻席建造者和外来的种类.元古代燧石中的微化石,尤其是蓝藻化石,尽管在元古代它们就已不断趋向于多样化,但由于它们形态上的保守性,对环境的指示比对地质时代的指示更有价值.高于庄组微化石的特点和大多数链状念珠藻垂直层理保存的事实表明:1.高于庄组微化石的个体大小随时间趋向于增大;2.高于庄组的沉积可能是处于一个淡水环境,且沉积率可能等于或少于微生物的生长率;3. 高于庄组织沉积模式可能是从潮间带至亚潮带或深海,然后再至潮间带或潮上带;4.当高于庄组沉积时真核生物亦已出现.
거금14～16억년적화북지구고우장조흑색층상、결핵상화투경상수석여첩층석적흑색규질부분중보존착겁봉부적원핵화진핵생물미화석.굉관조류재해조적혈암중역이발현.본조위평고중원고대생명상황、고배경화전현생주생물지층제공료중요적생물신식.흘금위지재고우장조지층중이유백여개화석충피인문인식.근거고식물화고배경적특정저사생물충류가분위삼개불동적조합,즉:1.전조화색구조조합,출현재고우장조일단,대표천수조석건조자화거주자여일사가능적외래부유생물적충류;2.념주조조합,부발생재해조적이단,환함일사저서조석건조자혹거주자적충류;3.제사단적색구조조합,타대표료조간대지아조대적조석건조자화외래적충류.원고대수석중적미화석,우기시람조화석,진관재원고대타문취이불단추향우다양화,단유우타문형태상적보수성,대배경적지시비대지질시대적지시경유개치.고우장조미화석적특점화대다수련상념주조수직층리보존적사실표명:1.고우장조미화석적개체대소수시간추향우증대;2.고우장조적침적가능시처우일개담수배경,차침적솔가능등우혹소우미생물적생장솔;3. 고우장조직침적모식가능시종조간대지아조대혹심해,연후재지조간대혹조상대;4.당고우장조침적시진핵생물역이출현.
Black bedded,nodular,and lenticular chert and silicified parts of stromatolites from the approximately 1 400-1 600 million year-old Gaoyuzhuang Formation,North China,contain remarkably well preserved microflora composed of diverse prokaryotic and possible eukaryotic microbes.Macroscopic algae have also been found.This Formation provides important paleobiological information from which to assess status of Mesoproterozoic life,and to evaluate paleoenvironmental conditions and pre-Phanerozoic biostratigraphy.The Gaoyuzhuang Formation has yielded over 100 taxa described by over 10 investigators.Most of the microbial taxa can be divided into three different assemblages according to their paleobiological and paleoenvironmental characteristics.1.The oscillatoriacean/chroococcacean assemblage which occurs in the first member of the Formation and this is interpreted to represent an assemblage from shallow water mat-building and mat-dwelling taxa with some possible planktonic taxa;2.the nostocacean assemblage found only in the second member,and includes benthic mat-building or mat-dwelling taxa;and 3.the chroococcacean assemblage of the fourth member,which represents intertidal to supratidal mat-building and allochthonous taxa.Proterozoic microfossils found in chert,especially cyanobacteria,are possibly more valuable as paleoenvironmental indicators than as chronostratigraphic tools because of their morphological conservation,although trends in diversity appear to exist for cyanobacteria in the Proterozoic.The general characteristics of Gaoyuzhuang microfossils,and the fact that most nostocacean chains occur and are preserved with the chain perpendicular to bedding indicate that:(1) the individual size of Gaoyuzhuang microfossils are part of a general trend of increase with time;(2) Gaoyuzhuang deposits are possibly in a fresh water environment and the rate of sedimentation might be equal to or less than the microbial growth rate;(3) the sedimentary model of Gaoyuzhuang might be from intertidal to subtidal or deep sea,and then to intertidal or supratidal;and (4) the eukaryotic organisms had densely occurred when Gaoyuzhuang Formation deposited.``