【摘要】 <正> 一.引言随着近年来地质勘测工作飞跃的发展,陆续发现了许多有关中国前寒武纪地层的新事实和新问题。1953年王曰伦等五台调查队著“五台山五台纪地层的新见”,认为:(i)五台系大部为滹沱系的花岗岩化变质部分;(ii)滹沱系底部为泳碛砾岩,其时代应属更多还原

【Abstract】 In this paper, the stratigraphic position of the Huto and the Sinian systemsis described. The Huto system was established by Willis and Blackwelder(1907)to denote the late Proterozoio formations lying between theirnamed palaeozoie Simian (Cambro-Ordovician) system and the older Proterozoica Wutaisystem. Grabau (1922)on the othe?hand, considering the Huto system as theequivalent of his Simian system, re-defined the latter term so as to designatethe first system of the Palaeozoic rocks well marked by an angular discordanceat its base, but with no distinct discordance at its top. His opinion of referringthe Sinian to the palaeozoic as its first system (Eo-Cambrian) though has notbeen unanimously accepted by the Chinese geologists, but the term of his sensehas become the general and current use since his proposal. About some thirty years ago, S. Yamane (1921), in his geological reconais-sance in the Huto tributary on the border of Hopei and Shansi provinces,found the Huto system lying clino-unconformably below the Sinian Hoshansandstone to the north of Chinghsing district. He considered that the Hutosystem might be a formational unit independent of either the Wutai or theSinian system of Grabau. Then arises the question as to whether the Hutosystem could be an independent member among the Pre-Cambrian rocks. According to the writer’s field observation together with the study of thelata so far gathered by various geologists, the stratigraphical succession of theWutaishan area can be schematized into three cycles of sedimentation and twoigneous activities as tabulated below:Palaeozoic cycle of sedimentation ………… Cambro-Ordovician Hsichowshan limestone Lower Cambrian Mante shale with basal conglomerate ——disconformity—— Sinian siliceous limestone with basal quartzite and conglomerate Peitai granite activity and unconformity Proterozoic cycle of sedimentation: Huto system Okou granite activity and unconformity Archaeanozoic cycle of sedimentation: Wutai system Basement not exposed The Wutai system is composed mainly of green schists with numerousintercalations of banded magnetite-quartz schist and some layers of metamor-phosed basic rocks of igneous origin. The Huto system may be classified, indescending order, into Tungyu limestone, Toutsun slate, Nantai quartzite andschist-conglomerate attaining about to 1600 m in total thickness. In the southernpart of the Wutaishan, the Wutai schist is unconformably overlain by theHuto system and the latter, being intruded by the Peitai gneissose granite, isin turn overlain clino-unconformably by the Cambrian strata. But, at thenorthern slope of the Peitai Peak, the Peitai gneisses, granite is overlain uncon-formably by the Sinian and Cambro-Ordovician strata. The Sinian systemcomprises mainly siliceous limestones, white quartzite in the lower part andconglomerate at the basal, with a total thickness of about 60 to 100 m. Only aparallel disconformity is observed to exist between the Sinian and the Cambro-Ordovician systems. From these field evidences, it is quite obvious that the Huto systemsuffered intence folding and was intruded by the Peitai granite prior to thedeposition of the Sino-Cambro-Ordovician formation. Hence, the writer does notagree with the traditional idea that the Huto system is entirely synonymouswith the Sinian as expressed by Grabau and other geologists, but is inclinedto ascertain that the Huto system is an independent Pre-Sinian formationalunit in the Pre-Cambrian stratigraphy of China. This conclusion may also bevindicated by the Palaeogeographical distribution of the Sinian system in Shansiprovince and the lithological characteristics, especially in the aspect as to the granitization of tho Huto system. In the writer’s opinion, the Huto system is widely distributed in southernand southwestern China. In these regions, tho so-called lower Sinian formationsmay bo considered to be the equivalents of the Huto system in North China intheir lithological characters and stratigraphic succession. These so-called lowerSinian formations, such as the Kunyang series in Yunnan, the Panchi series inHunan, and the Shuangchiao series in Kiangsi, were no doubt strongly foldedprior to the deposition of the Sinian molassic sandstone and tillite. Recently, the Huto system is definitely observed in tho Sungshan district,Honan province. According to E.T.Chang (1953), the metamorphosed Sungshanquartzite with conspicuous cross-bedding is overlain clino-unconformably bythe Wufeshan series and this is in turn overlain clino-unconformably bySinian Tashihmen quartzite with intercalations of slaty shales. The SinianTashihmen quartzite in overlain disconformably by the lower Cambrian Chu-shatung vareigated limestone and further upward comes the so-called Mantoshale. The Wufeshan series comprises mainly siliceous collenia-bearing limestonewith variegated. slate and quartzite of a total thickness about 600 m. The writerconsiders that the Wufeshan series which unconformably underlies tho Siniansystem could bo correlated to the Huto system. In the Liaotung Peninsula and North Korea there is the Shogen system orthe so-called Sinian system over 8000 m at the thickest. The Shogen system inNorth Korea, has once been presumed to belong to the Sinian system byS. Matsusita (1935). In the ascending order, it consists mainly of quartziteand slate. the Chokken series, limestone and dolomite, the Shidogu series andvariegated slates, quartzite and limestone the Kuken series, these three seriesbeing called the Tahoshangshan, the Kuantung and the Nanshan seriesrespectively in the Liaotung Peninsula. According to Matsusita’s late report(1947), the unconformity relation was found at some places in the so-calledShogen system and, furthermore, the Chokken series is found to be intrudedby the Seikoshin gneissose granite at Korea, Eastern Kokaido, North Korea.Accordingly the lower and middle parts of the Shogon system may be corre-lated with the Huto system in North China instead of the Sinian as consideredonce by many geologists. Generally speaking, the lithological character of theSinian system in various regions, except in the Chihsien-Hsinglung area, israther similar: being in the lower part composed chiefly of quartzite and inthe upper part of siliceous limest ne with a total thickness of from less than 100 m to more than 4000 m. Lateral face change from siliceous limestone toquartzite formation is observed at some places in the Pre-Sinian highland inShansi province. The transition from the uppermost part of Sinian to thelower Cambrian system is often gradual as seen here and there. As there isno remarkable stratigraphical discordance in the Sino-Cambrian succession inChina, usually the dividing line between the two systems is arbitrarily drawn.Some twenty years ago, at Ch’angping district, north of Peking, W. Y. Chang(1935) found some tribolites in the so-called Sinian Chingerhyu limestone.Recently, at some places the lower Cambrian tribolites have also been foundin the variegated limestone below the so-called lower Cambrian Manto shale.In accordance with the current opinion, the lower limit of the Cambriansystem should be drawn at the basal quartzite sandstone of the Hsimalingformation. The solution of the Sinian stratigraphic problem in China, depends onessentially the recognition of the independent stratigraphic position of Hutosystem, and tho lower limit of tho Cambrian system as to reveal tho actualdemarkation of the Sinian system.更多还原