新疆塔里木玉北井区早奥陶世古环境及生态组合时空分布

新疆塔里木板块玉北地区下奥陶统沉积于极浅海带碳酸盐岩沉积区,化石密度普遍很低,依据该地区6口钻井的化石碎片类型以及所赋存的围岩特征可划分出6种生态组合:三叶虫-介形类组合或介形类组合;介形类-三叶虫组合或三叶虫组合;棘屑-三叶虫组合;三叶虫-棘皮类组合;海绵-三叶虫-介形类组合和三叶虫-腕足类组合。生态组合和沉积微相分析表明,玉北地区该地质时期共有三次沉积环境变迁:蓬莱坝组顶部-鹰山组底部沉积期为局限台地潮坪环境;鹰山组下部沉积期为局限台地潮坪与潮沟交互环境;鹰山组中部沉积期为局限台地潮坪环境;鹰山组上部沉积期为局限台地潮坪与潮沟交互或者局部的局限台地潮坪环境。     

西南地区志留纪彗星虫科三叶虫

本文主要论述以下几点:1)西南地区至今为止已发现的志留纪三叶虫大致有30多个属,80多个种。2)较集中产出于两个层位,一是下志留统的香树园组至雷家屯组或与其相当的层位。另一是中志留统的秀山组。前者以翼斜视虫Ptilillaenus 为代表,后者则是以王冠虫Coronocephalus 为主的三叶虫组合。3)这两个三叶虫动物群组合除个别属种外,多数为我国特有,和其共生的笔石、腕足类等有的可与国际对比。4)区别王冠虫属和似彗星虫属在本区及邻近地区志留纪地层对比有一定意义。前者仅见于中志留统的秀山组,后者在我国自晚奥陶世至晚志留世的地层中都有发现。5)滇东关底组的东方棘尾虫Acanthopyge orientalis Wu及玉龙寺组的Warburgella rugulosa (Alth) sinensis Wu 的发现为滇东志留泥盆系的划分和对比提供了重要的三叶虫化石依据。6)系统描述彗星虫科的一些新属种。     

江南古陆北侧下志留统秀山组上段Encrinuridae科三叶虫新材料

志留纪扬子浅海繁衍了一个独特的慧星虫科(Encrinuridae)三叶虫,以江南古陆北侧滨、浅海区最为繁盛。本文根据3个剖面(插图1)的资料讨论下志留统秀山组上段三叶虫分带,并描述Encrinuridae科的一些新种,这些三叶虫标本是1981年李志明带领方德庆等6名学生实习时获得,赠予本人;化石图片由刘金华、陈斌拍摄,笔者在此表示衷心谢意。方德庆在利用上述资料编写毕业论文时对三叶虫进行了初步鉴定和描述,后由杨家騄重新研究完成。     

贵州松桃黄莲寒武系都匀阶杷榔组三叶虫地层划分及意义

贵州松桃县黄莲村西的黄莲剖面杷榔组厚417.8m,主要由深灰色钙质泥岩组成,岩性与湘西、黔东杷榔组基本相似,除底部38m未见三叶虫外,以上均含有三叶虫,由下而上可分为2个三叶虫带,下为Oryctocarella duyunensis带(38-83m),化石较少;上为Oryctocarella duyunensis-Arthricocephlus chauveaui组合带(83 m以上)。除Arthricocephlus chauveaui外,还含有A.xinzhaiheensis,Oryctocarella duyunensis,O.sibirica?,O.balangensis,Duyunaspis duyunensis,Changaspis elongata及Redlichia (Pteroredlichia)murakamii。与剑河交榜潜在的寒武系第四阶国际层型剖面下部2个三叶虫带Oryctocarella duyunensis-Arthricocephlus chauveaui组合带及Oryctocarella duyunensis带完全相同,也可和格陵兰北部Freachen land及Peary land等地Henson Gletscher组对比。黄莲剖面是潜在的寒武系第四阶国际层型剖面剑河交榜杷榔组剖面的良好辅助剖面。     

湖北宜昌奥陶纪大湾组的三叶虫新种

本文记述湖北宜昌地区奥陶纪大湾组下部的一个三叶虫新种Ovalocephalus eoprimitivus sp．nov．,主要特征是头鞍缺失前颈环横沟。Ovalocephalus Koroleva为泛冈瓦纳的标志分子,在中国奥陶系分布极为广泛。这一新种的时代为弗洛期一大坪期,系该属目前所知地层层位最低的分子。     

湖北宜昌奥陶纪大湾组的三叶虫新种Ovalocephalus eoprimitivus sp. nov.

本文记述湖北宜昌地区奥陶纪大湾组下部的一个三叶虫新种Ovalocephalus eoprimitivus sp.nov.,主要特征是头鞍缺失前颈环横沟。Ovalocephalus Koroleva为泛冈瓦纳的标志分子,在中国奥陶系分布极为广泛。这一新种的时代为弗洛期—大坪期,系该属目前所知地层层位最低的分子。     

中国贵州东部乌溜-曾家崖剖面早—中寒武世凯里组疑源类(英文)

我国贵州东部乌溜-曾家崖凯里组剖面作为世界早-中寒武世界线层型侯选剖面,产出良好保存的大型无脊椎动物化石(尤其是三叶虫)。因此,更加详细研究该剖面海洋疑源类的生物地层非常重要,将提供围绕界线的生物和环境变化的细微记录。乌溜-曾家崖剖面凯里组的疑源类划分两个组合,它们是凯里组0-52m的Leiomarginata si mplex-Fi mbriaglomerella membranacea组合和52-140m的Cristallinium cambriense-Heliosphaeridiumnodosum-Globosphaeridiumcerinum组合。140-214m仅有很少疑源类标本,可能因为凯里组上部以白云岩为主,不适宜有机壁微体化石的保存。距凯里组底部往上约52m处疑源类组合出现重大变化,无疑为解释沉积环境提供重要资料。两疑源类组合间界线,位于52.3-52.7m,此稍低于被三叶虫Oryctocephalusindicus首现所指示的全球寒武系第5阶潜在层型剖面界线。     

应用聚类分析研究我国palaeolenid类三叶虫分类——兼论我国黔东统沧浪铺组乌龙箐段生物带划分

文中通过对我国己发表的palaeolenid类三叶虫中的34个种头盖特征组合进行Q型聚类分析,研究我国palaeolenid类三叶虫属种的分类,并结合传统定性分析,对该34个种(包括2个属、1个亚属和1个亚种)进行修订,且合并成1个属4个种(亚种),即:Palaeolenus douvillei Mansuy,1912,Palaeolenus lantenoisi Mansuy,1912,Palaeolenus lantenoisi longispinus(Chang and Chu,1980)和Palaeolenus fengyangensis Chu,1962。文中还提出沧浪铺组乌龙箐段可采用Palaeolenus fengyangensis带(上)和Palaeolenus lantenoisi带(下)两生物带意见。     

黔东早—中寒武世凯里组疑源类组合及其界线意义

通过对台江八郎和丹寨两条剖面凯里组中疑源类化石的分析,研究,台江剖面产疑源类化石有17属35各（12未定种）,其中以Leiosphaeridia,Synsphareidium,Cymatiosphaera,Pterospermella最为丰富,可划分为3个组合,即Cymatiosphaera cf.cristata-Fimbriaglomerella memebrancea组合,Cristallinium-Micrhystridium-Pterospermella组合和Dictyotidium-Granomarginata组合,丹寨平寨剖面凯里组所产疑源类化石有：13属21种（5未定种）,同样划分为3个组合,即Leiosphaeridia-Tasmanites组合,Retisphaeridium-Micrhystridium tentatium组合和Baltisphaeridium-Bubomorpha hunjiangensis组合,本文对两条剖面中的凝源类化石的组成,相对含量做了详细的统计,发现在八郎剖面9－2层和平寨剖面3层疑源类的丰度,分异度开始发生明显的变化,表现由早寒武世向中寒武世疑源类组合面貌的转变,这一疑源类转变层位正好是与三叶虫划分的中,下寒武统界线的层位位置相一致,这充分表明疑源类化石可作为划分中,下寒武统的极有价值的微体生物化石证据。     

安徽淮南寒武纪一新三叶虫属——Huaiaspis

安徽淮南八公山地区寒武纪毛庄-徐庄期地层出露良好,化石丰富。在老鹰山剖面徐庄组底部的紫色页岩内所采集大量三叶虫标本中发现的一种新的三叶虫,命名为Huaiaspishuainanensisgen.etsp.nov.,它代表了一个尚未描记的且科级分类位置待定的新属新种。该三叶虫特点突出,是头部特征极度消隐且不具眼、眼叶、眼脊的“盲三叶虫”。该三叶虫为小尾型后颊类,主要特征为:壳面光滑,背壳呈次椭圆形,头盖半圆形;头鞍呈钟形向前收缩;背沟浅,仅在侧光下可见;活动颊平滑宽大,具有宽阔的活动颊刺;胸部由14节组成;尾部中轴粗壮,无边缘沟。     

EARLY ORDOVICIAN (ARENIG) TRILOBITE PALAEOECOLOGY AND PALAEOBIOGEOGRAPHY OF THE SOUTH CHINA PLATE

Abstract:  Faunal composition of South Chinese Arenig benthic trilobite associations is investigated using the multivariate techniques of TWINSPAN, DCA and seriation. Eight fairly distinct benthic associations can be differentiated, organized primarily along a palaeobathymetrical gradient across the Yangtze Platform in southern Shaanxi and western Hubei and the Jiangnan Transitional Belt in northern Hunan: the Taihungshania , Neseuretus , Trinucleid and Asaphid- Pseudocalymene associations (shallow shelf), the Asaphid-Raphiophorid and Nileid-Asaphid associations (< 100 m outer shelf), the Nileid-Illaenid Association (deep outer shelf carbonates) and the Pseudopetigurus Association (deep outer shelf clastics). The highest levels of diversity are displayed by the Asaphid-Raphiophorid Association of western Hubei. Investigation of the biogeographical affinities of this fauna indicates that South China is biogeographically closest to the other Chinese geotectonic units, and displays strong faunal connections to other central and eastern Asian regions as well as to Tethyan and South American regions. Subdivision of the South Chinese trilobite fauna into different depth zones shows a statistically significant correlation between increasing water depth and increasing faunal cosmopolitanism, although taxa endemic to China or Gondwana also occur even in slope faunas. The results of this biogeographical analysis are consistent with a tropical or subtropical peri-Gondwanan association of South China with other Asian terranes.     

Two new species ofPseudopetigurus (Trilobita) from the Arenig — Llanvirn of South China

Two new species ofPseudopetigurus are described from northern Hunan Province, China.P. deprati n. sp. is abundant in the upper Zitai Formation (upper Arenig) of Shuanghong, Baiyun, Shimen County, andP. expansus n. sp. occurs throughout the Jiuxi Formation (Arenig — lower Llanvirn) of Panjiazui, Taoyuan County. These formations represent outer shelf facies from the Jiangnan Transitional Belt of the South China Plate, close to the southeast margin of the Yangtze Platform. BothP. deprati andP. expansus show similarities to Upper Ordovician species ofPseudopetigurus recorded from South China. Other species ofPseudopetigurus are known almost entirely from cranidia, but pygidia and librigenae are also described for both new species, and the first known hypostome assigned to the genus is described forP. expansus. These two species are ecologically important members of offshore trilobite faunas during the Arenig — Llanvirn and define the outer shelfPseudopetigurus Association of South China. Despite being a deep-water genus,Pseudopetigurus is biogeographically restricted to the western margin of the Gondwanan craton and neighbouring regions of Baltica.      

A new late Katian (Late Ordovician) trilobite association from Zhenxiong,northeastern Yunnan,Southwest China and its palaeoecological implications

A new late Katian (Late Ordovician) trilobite association is documented from the Daduhe Formation in Zhenxiong, northeastern Yunnan, including 17 species of 15 genera, among which four species (Malongullia sinensis, M. zhenxiongensis, Taklamakania paucisegmentatus and Amphitryon constrictus) are new. Lithologic and faunal evidence enables the recognition of a new association with medium diversity, named the Taklamakania Association. It is a typical representative of the Raphiophorid Community that lived in a deep subtidal environment close to the anoxic basin. A total of five trilobite ecological associations were found to occur in South China during the late Katian, in relation to the environmental gradients ranging from shallow subtidal zone, deep subtidal zone, slope to dysoxic shaly basin.     

Facies of a Lower Ordovician carbonate shelf (Mungok Formation: Taebaeksan Basin,Korea)

Summary The lithologic associations within the Lower Ordovician Mungok Formation in Korea define four depositional facies that formed across a continental margin fringing the Sino-Korean block: these facies represent lagoonal/restricted marine, shoal, inner shelf, and outer shelf environments. The stacking pattern of these facies reveals two systems tracts composed of five depositional sequences. The lower highstand systems tract consists of the lagoonal/restricted marine and shoal facies, whereas the upper lowstand systems tract comprises, in ascending order, inner shelf, outer shelf, and inner shelf facies. Three trilobite biofacies are recognized in the Mungok Formation: i.e.,Yosimuraspis, Kainella, andShumardia biofacies in ascending order. TheYosimuraspis Biofacies is dominated byYosimuraspis but also containsJujuyaspis andElkanaspis. The predominance of the endemic eponymous taxon suggests a lagoonal/restricted marine environment. The nearly monotaxicKainella Biofacies, which comprises pandemic genera such asKainella and occasionallyLeiostegium, may represent a less restricted environment than theYosimuraspis Biofacies. TheShumardia Biofacies occurs in the marlstone/shale lithofacies through relatively thick stratigraphic interval and is dominated by cosmopolitan trilobite taxa with some endemic species. The lithofacies and cosmopolitan trilobite assemblage of theShumardia Biofacies indicate that it occupied an outer shelf environment. The vertical succession of lithofacies and trilobite biofacies in the Mungok Formation records in general a shift from a restricted, shallow water environment to deeper-water environment.     

Rusophycus carleyi (James, 1885), Trace Fossils from the Lower Ordovician of Southern Morocco,and the Trilobites that Made Them

Thin-bedded, pyrite-rich, fine sandstones and mudstones of the Floian-Dapingian Upper Fezouata Formation contain abundant trace fossils Rusophycus carleyi in close association with a species of the asaphid trilobite Asaphellus. The sizes and shapes of this trilobite and the traces match closely. Five specimens have even been found where an articulated specimen of Asaphellus appears to be directly located over a specimen of Rusophycus carleyi within a thin bed of sandstone, suggesting that the trilobite animal may have been trapped on top of a trace that it had just made. Such intimate associations between a putative tracemaker and a trace are rare in the fossil record and particularly rare for Trilobita. The number of coxal impressions that form part of R. carleyi, eleven, matches the number expected for an asaphid trilobite (one for each of eight thoracic segments and one for each of three post-oral cephalic appendages). Impressions of the hypostome, thoracic tip impressions, cephalic margin, and pygidial margin in a few of the traces also match those of this asaphid trilobite. R. carleyi has been found in Ordovician strata of other parts of the world in association with asaphid trilobites.     

奥陶纪三叶虫Omeipsis zhenxiongensis Luo,1974的新材料

对滇东镇雄羊场桃子崖(北纬27°36′53″, 东经104°37′42″)和芒部刘家沟(北纬27°36′22″, 东经104°52′30″)早奥陶世晚期湄潭组下部所产Omeipsis zhenxiongensis Luo, 1974新材料作了研究,得以揭示Omeipsis Kobayashi, 1951的完整形态特征.该属除尾部具有一长一短两对边缘刺外,其头鞍向前逐渐扩张并发育有粗壮前刺.Renhuaia Yin in Yin and Li, 1978应为Omeipsis的晚出异名,因为两者头盖并无显著差异.     

湖北宜昌地区下-中奥陶统界线疑源类生物地层学意义

根据牙形类Baltoniodus? triangularis的首现,中奥陶统和大坪阶底界已界定于湖北宜昌黄花场剖面大湾组底界之上10.57m.对黄花场剖面以及邻近的大坪剖面大湾组疑源类研究表明,某些疑源类属种具有生物地层学意义,其首现可用于识别奥陶系下/中统界线.     

ASAPHOID TRILOBITES FROM THE ARENIG–LLANVIRN OF THE SOUTH CHINA PLATE

Abstract:  Twenty-nine Arenig and Llanvirn trilobite species, representing 20 genera in the Asaphidae, Cyclopygidae, Dikelokephalinidae, Nileidae, Raphiophoridae, Remopleurididae, Taihungshaniidae and Trinucleidae, are treated in a taxonomic review of the South Chinese Asaphida. This review is based on large collections of trilobite material made from five formations at nine localities in western Hubei, northern Hunan and southern Shaanxi, representing a wide range of benthic marine environments across the Yangtze Platform and Jiangnan Transitional Belt regions of the South China Plate. Most South Chinese representatives of the Asaphidae are reassigned to the Nobiliasaphinae on the basis of cranidial and hypostomal characters, and taxonomic revisions are given for Liomegalaspides and Opsimasaphus pseudodawanicus . Taihungshania shui and T . tachengssuensis are revised and redescribed, and the establishment of lectotypes for these species and T . brevica clarifies the status of the type material of Taihungshania . Nileus walcotti is revised and restricted biogeographically to the South China Plate; material from Xinjiang previously assigned to this species is reassigned to N .  sericeus sp. nov. The new raphiophorid species Raphioampyx sinankylosus is described. Aocaspis , Incaia and Raphioampyx are recorded for the first time from South China, and the latter two genera are also recorded for the first time from the Arenig.     

山东寒武系苗岭统三叶虫消化系统的化石证据

三叶虫是寒武纪演化动物群中最引人注目的成员之一,其内部解剖结构一直以来受到广泛关注。与其他非生物矿化软体结构相比,三叶虫的消化系统更容易留下化石记录,为探索其内部结构提供了难得的机会。本文描述了来自山东省潍坊市寒武系馒头组的Proasaphiscus, Lioparia, Deiradonyx和Iranoleesia,以及临沂市寒武系张夏组的Maotunia共五个三叶虫属的消化系统。这些保存较好的标本展示了三叶虫的四对头部消化腺,以及可能的头部消化腺与"嗉囊"共存的例子,为了解三叶虫消化系统尤其是头部消化系统的结构提供了新的信息。三叶虫非生物矿化软体结构的保存也显示了这些层位有发现布尔吉斯页岩型特异埋藏化石的潜力。