PRELIMINARY OBSERVATION ON THE PRE-DEVONIAN STRATIGRAPHY OF SOUTHERN KIANGSI
PRELIMINARY OBSERVATION ON THE PRE-DEVONIAN STRATIGRAPHY OF SOUTHERN KIANGSI
复制标题
DOI：
--
复制
发表时间：
1964
期刊：
影响因子：
--
通讯作者：
C. Chang;C. Uang
中科院分区：
文献类型：
--
作者：
C. Chang;C. Uang
江西南部前泥盆纪地层已被许多地质学家研究过。关于这些地层的地质年代的意见一直是相互矛盾的，因为在1960年以前没有在这些地层中发现化石。1943年初，k.c。徐认为赣南前泥盆世地层包括震旦纪到下古生代的地层，但其他人认为它们可能都是前震旦纪。1957年以来，南京大学地质系多次到赣南考察，并于1960年和1961年对该地区进行了系统的地质调查，在该地层的几个层位发现了大量的笔石、三叶虫、原海绵体等化石。在此基础上，确认该区存在震旦系至下古生代地层。根据研究结果，本区前泥盆统地层总厚度超过12000米，属于典型的地槽沉积。本文对本区前泥盆世地层进行了由高到低的总结：前震旦纪（下元古代）(1)大禹群。它是本区最古老的地层，由片岩、千层岩、片岩、大理岩、石英岩、千层板岩等组成。，总厚度超过2017米。(2)利春集团。为浅灰色和灰绿色变质场，石英砂岩（灰岩）和绢云母千层岩，散有磁铁矿晶体，总厚度3471余米。立春集团和大禹集团之间的联系尚未确定。2. 震旦系—古亭群：该组由灰黑色和深灰绿色灰砾岩、黑色碳质、硅质板岩嵌套燧石层组成，上部为薄灰岩透镜体，顶部为基性挤压岩，总厚度约1707米。古亭集团和立春集团之间的联系尚未确定。3. 下寒武统——河塘组：以灰黑色硅质、碳质板岩、粉砂岩为主，上部穿插灰绿色灰岩，基底为石煤、薄层燧石层，厚度428米。在黑色板岩中，原海绵体大量存在。该组不整合位于震旦系古亭群之上。中、上寒武统——巴山群：为典型的复理石组，以灰绿色和灰黑色灰砾岩、粉砂岩和板岩为特征，总厚度2237米。在巴山群下部发现了大量保存完好的原海绵体化石。该组整合覆盖下寒武统河塘组。下奥陶统(1)银竹布组：由浅灰色和灰绿色粉砂岩与板岩互层组成，具有微节律构造，厚度467 ~ 637米。该组整合于中、上寒武统之上，与含笔石的宁国组整合。认为该组属于下奥陶统早期，与浙西银竹堡组和英国地区的特雷马多纪相当。(2)宁国组：该组由浅灰色、灰绿色粉砂岩、灰黑色硅质、碳质板岩组成，厚度887 ~ 967米。其特别特点是笔石化石丰富，包括didymograptus hirundo，D。异常、长耳舌象、叶状舌象、大斑舌象、翼形舌象、中国舌象、nicholsongraptus、forticudatus、Cryptograptus tricornis、C.sh（a bbb¨¨）feri、pseudolimacgraptus、Glossograptus、Glyptograptus、Orthograptus等这些化石可能与浙江西部和皖南的Amplexograptus confertus带和Didymograptus hirundo带有关。中奥陶世—胡罗组：黑色硅质板岩、燧石层与碳质板岩互层，厚度大于89米。该地层还含有丰富的笔石化石，包括Dicellograptus sex-tans var.exilis，D。史密斯、sckarenbergi假笔、Didymograptus euodus、calcaratus、Climacograptus、Trigonograptus、Glyptograptus等。都相当于浙江西部和安徽南部的股横带。属于中奥陶世早期。它整合地盖在宁国组上。7. 上奥陶统——沙春群：该组由灰黑色灰砾岩和带状板岩组成，基底砾岩厚度为15米，具有明显的复理石质韵律。丰富的化石，包括笔石、三叶虫和介形虫。发生在他们身上。这个地层的总厚度估计超过1300米。沙春群与下伏地层的接触可能为角不整合。
The Pre-Devonian strata of southern Kiangsi have been studied by many geologists.Opinions regarding the geological ages of these strata have been conflicting,since no fos-sils were found in them before 1960. Early in 1943,Prof.K.C.Hsu assumed that the Pre-Devonian strata of southernKiangsi included formations ranging from Sinian to Lower Palaeozoic in age,but othersheld that they might be all of Pre-Sinian in age. Since 1957,the faculty of the Geological Department of Nanking University re-peatedly visited southern Kiangsi and in 1960 and 1961,during the course of systematicgeological survey of this area,they found abundant fossils,including graptolites,trilobitesand Protospongia,from several horizons in these strata.On the basis of this discovery,the existence of Sinian to Lower Palaeozoic formations in this area is confirmed.Ac-cording to the result of our study,the Pre-Devonian strata in this area exceed 12,000meters in total thickness,and belong to typical geosynclinal sediments. In this paper the Pre-Devonian formations of this area are summarized in ascendingorder as follows: 1. Pre-Sinian(Lower Proterozoic) (1) The Dayu Group.It is the oldest formation in this area,composed of schists,phyllites,schistose,marbles,quartzites,phyllitic slates,etc.,with a total thickness of morethan 2,017 meters. (2) The Lichun Group.It is of light gray and grayish green metamorphic felds-pathic-quartzose sandstone(graywacke)and sericite-phyllite with scattered magnetite cry-stals,with a total thickness of more than 3,471 meters.The contact between the LichunGroup and the Dayu Group has not yet been defined. 2. Sinian——The Guting Group:This formation is composed of grayish black anddark gray-green graywacke,black carbonaceous and siliceous slate intercalated with flintlayers,and thin limestone lenses in the upper part and basic extrusive rocks at the top,with a total thickness of about 1,707 meters.The contact between the Guting Groupand the Lichun Group has not yet been defined. 3. Lower Cambrian——The Hetang Formation:It is mainly of grayish blacksiliceous and carbonaceous slate and siltstone,intercalated with grayish green graywacke inthe upper part,and stony coal and thin-bedded flint layers in the basal part,with a thick-ness of 428 meters.In the blackish slates Protospongia occurs in abundance.Thisformation lies disconformably upon the Sinian Guting Group. 4. Middle and Upper Cambrian——The Bazhan Group:It is a typical flysch forma-tion,consisting characteristically of grayish green and grayish black graywacke,siltstone and slate,with a total thickness of 2,237 meters.Abundant well-preserved fossils ofProtospongia were obtained from the lower part of the Bazhan Group.This formationconformably overlies the Lower Cambrian Hetang Formation. 5. Lower Ordovician (1) The Yinzhubu Formation:It is composed of light gray and grayish green silt-stone interbedded with slate,having microrhythmic structure,with a thickness of 467—637meters.This formation lies conformably upon the Middle and Upper Cambrian,and isalso conformably succeeded by graptolite-bearing Ningguo Formation.Thus this formationis considered to be of early Lower Ordovician in age,and is equivalent to the YinzhubuFormation of western Chekiang and the Tremadocian of the British region. (2) The Ningguo Formation:This formation is composed of light gray and grayishgreen siltstone,grayish black siliceous and carbonaceous slate,with a thickness of 887—967 meters.It is especially characterized by abundant fossils of graptolites,includingDidymograptus hirundo,D.abnormis,Amplexograptus confertus,phyllograptus anna,Tetragraptus bigsbyi var.latus,Pterograptus sp.,Sinograptus sp.,Nicholsonograptus sp.,Climacograptus forticudatus,Cryptograptus tricornis,C.sh(a|¨)feri,Pseudoclimacograptus sp.,Glossograptus sp.,Glyptograptus sp.,Orthograptus sp.,etc.These fossils may be cor-related with the Amplexograptus confertus zone and Didymograptus hirundo zone ofwestern Chekiang and southern Anhwei. 6. Middle Ordovician——The Hulo Formation:It is of black siliceous slate andflint layers interbedded with carbonaceous slate,with a thickness of more than 89 meters.This formation contains also abundant fossils of graptolites,including Dicellograptus sex-tans var.exilis,D.smithi,Pseudoclimacograptus sckarenbergi,Didymograptus euodus,Orthograptus cf.calcaratus,Climacograptus sp.,Trigonograptus sp.,Glyptograptus sp.,etc.all equivalent to the Nemagraptus gracilis zone of western Chekiang and southern Anhwei.and belong to the early Middle Ordovician.It overlies conformably the Ningguo Forma-tion. 7. Upper Ordovician——The Shachun Group:This formation,possessing apparentrhythm of flysch,consists of grayish black graywacke and banded slate,with a basal con-glomerate of 15 meters.Abundant fossils,including graptolites,trilobites and ostracods.occur in them.The total thickness of this formation is estimated at more than 1,300meters.The contact between the Shachun Group and the underlying formation may bean angular unconformity.