前科迪勒拉（阿根廷）寒武─奥陶纪牙形刺和沉积演化

阿根廷前科迪勒拉区寒武─奥陶系地层发育。中晚奥陶世时,前科迪勒拉东部与中部山区为浅水陆棚相,西部山区为斜坡─盆地相。牙形刺的分布主要与平静的暖水大洋有关。寒武纪仅发现晚寒武世Ｐｒｏｃｏｎｏｄｏｎｔｕｓ带,此期间有一次海侵事件。在奥陶纪发现了牙形刺并可识别出四次海侵事件三次海退事件和二次缺氧事件。     

前科迪勒拉（阿根廷）寒武——奥陶纪牙形刺和沉积演化

阿根廷前科迪勒拉区寒武－奥陶系地层发育。中晚奥陶世时,前科迪勒拉东部与中部山区为浅水陆棚相,西部山区为斜坡－盆地相。牙形刺的分布主要与平静的暖水大洋有关。寒武纪仅发现晚寒武世Ｐｒｏｃｏｎｏｄｏｎｔｕｓ带,此期间有一次海侵事件。在奥陶纪发现了牙形刺并可识别出四次海侵事件三次海退事件和二次缺氧事件。     

新疆库鲁克塔格早寒武世西大山组的三叶虫

库鲁克塔格地区的寒武纪地层,早在1928—1932年间,诺林(E.Norin)曾作过不少工作,并将本区寒武系命名为“突尔沙克塔格建造”(E.Norin,1937),标准剖面地点在库鲁克塔格西部的突尔沙克塔格及却尔却克山一带。所采化石经丘迪生(G.T.Troedsson,1937)研究,判定动物群的时代为晚寒武世,其中以三叶虫为主。张日东、俞昌民等(1959)根据莫合尔山北坡所测的寒武系剖面,划分为三个统:即突尔沙克塔格统(上统)、莫合尔山统(中统)及西大山统(下统)。近年来,新疆地质局等单位组成的新疆前寒武纪地质研究组,及章森桂、高振家(1981)根据莫合尔山北坡及西大山的下寒武统剖面,将原来的西大山组一分为二。下寒武统上部仍沿用“西大山组”一名,仅限于代表下寒武统上部的一套碳酸盐岩;而下寒武统下     

新疆塔里木板块巴楚隆起区寒武系石盐氯同位素研究

塔里木板块巴楚隆起区主体部位的寒武纪地层多为典型浅水局限台地蒸发相、潟湖相沉积,在早中寒武世时期沉积石膏与岩盐层。本次研究对中寒武世阿瓦塔格组石盐进行了氯同位素分析,发现该地区的海水存在强烈的陆源水体输入。     

江苏昆山早寒武世三叶虫

1979年江苏第六普查勘探大队于昆山玉山镇2号钻井岩芯中获得了丰富的早寒武世三叶虫化石,这是继昆1井取得丰富的中、晚寒武世三叶虫之后又一重要发现,由于这些资料的取得,为本区寒武系提供了比较系统而完整的地层剖面和三叶虫资料。长期以来,在下扬子地区除宁、镇外,在镇江以东的广大地区未有寒武系的报道,所以昆山寒武系三叶虫的发现十分引人注意。     

论寒武纪小山城子属

根据唐山市丰润区左家坞镇半壁山寒武系炒米店组下部含海绿石灰岩夹竹叶状灰岩中采集的三叶虫标本, 对小山城子虫属的定义和时代进行了修订, 将后平壤虫Metapianaspis Qian, 1994, 扎浪滩虫Zhalangtania Zhou in Zhou et al., 1996与小山城子虫属合并; 对其时代和分类位置进行了讨论, 将小山城子虫属归于唇头虫科 Cheilocephalidae Shaw, 1956, 在华北寒武系苗岭统顶部新建了Liostracina simesi-Placosema convexa带, 对于华北浅水台地相区和华南深水斜坡相区地层对比具有重要意义。     

贵州麻江羊跳寒武系九门冲组微体化石初探北大核心CSCD

贵州麻江羊跳剖面寒武系九门冲组发育一套富含有机质的灰岩,经室内醋酸浸泡处理后,发现有海绵动物骨针和腕足动物的微体骨骼化石。海绵动物骨针包括粗短三轴六射针和细长三轴六射针。腕足动物经对比研究后将其鉴定为Eohadrotreta zhenbaensis,外部特征和内部结构均与陕南和鄂西地区的E.zhenbaensis非常相似,具有贝体轮廓亚圆形或横卵形、壳体饰以明显的同心纹,腹壳内顶坑浅弱或不发育、顶突起微凸,背壳假铰合面明显、中间沟和中支板发育良好等特征。E.zhenbaensis主要见于中国扬子区陕南和鄂西的寒武纪第二世地层中,在黔东斜坡相区九门冲组中尚属首次报道。E.zhenbaensis在黔东寒武系九门冲组的发现,不仅丰富了该组的生物组成面貌,扩展其地理分布,而且可为扬子区和过渡区不同岩石地层单位之间的对比提供信息。麻江羊跳寒武系九门冲组微体化石远较鄂西和陕南等地水井沱组中微体化石的分异度低,可能与当时麻江地区水体较深有关,为研究不同相区生物群落结构的变化提供了资料。     

贵州麻江羊跳寒武系九门冲组微体化石初探

贵州麻江羊跳剖面寒武系九门冲组发育一套富含有机质的灰岩,经室内醋酸浸泡处理后,发现有海绵动物骨针和腕足动物的微体骨骼化石。海绵动物骨针包括粗短三轴六射针和细长三轴六射针。腕足动物经对比研究后将其鉴定为Eohadrotreta zhenbaensis,外部特征和内部结构均与陕南和鄂西地区的E.zhenbaensis非常相似,具有贝体轮廓亚圆形或横卵形、壳体饰以明显的同心纹,腹壳内顶坑浅弱或不发育、顶突起微凸,背壳假铰合面明显、中间沟和中支板发育良好等特征。E.zhenbaensis主要见于中国扬子区陕南和鄂西的寒武纪第二世地层中,在黔东斜坡相区九门冲组中尚属首次报道。E.zhenbaensis在黔东寒武系九门冲组的发现,不仅丰富了该组的生物组成面貌,扩展其地理分布,而且可为扬子区和过渡区不同岩石地层单位之间的对比提供信息。麻江羊跳寒武系九门冲组微体化石远较鄂西和陕南等地水井沱组中微体化石的分异度低,可能与当时麻江地区水体较深有关,为研究不同相区生物群落结构的变化提供了资料。     

河南淅川志留纪三叶虫

我国地层分区的华北区及秦岭区,在河南西南部由北西走向的伏牛山所分隔。伏牛山由前寒武系变质岩所组成,南北的宽度有60km。淅川位于河南西南部,属秦岭区。在淅川附近有震旦系、寒武系、奥陶系、志留系、泥盆系及石炭系等不同地质时代的岩层分布,与华北区的差异比较大,如志留系、泥盆系在华北区没有沉积;震旦系、寒武系、奥陶系的沉积和动物群与华北区相比也有很大不同。秦岭区在河南西南部与湖北西北部像个楔形夹在华北区与扬子区     

东秦岭中部晚奥陶世腕足类*

报道东秦岭中部晚奥陶世腕足类19属20种，其中4新种。该区晚奥陶世腕足类与浙赣、陕甘宁及青海等地区同属华南华北腕足动物地理区。此区与北欧区较接近，它可能与哈萨克地区一起形成一个独立的腕足动物地理区，或为北欧区的一个亚区。它与准噶尔兴安区明显不同，后者属北美区     

山东潍坊寒武系苗岭统乌溜阶馒头组上部的腕足动物

寒武系腕足动物属种多样性高、个体数量丰富、形态差异明显、地理分布广泛,具有辅助寒武系三叶虫生物地层划分和对比的潜力。华北板块寒武系苗岭统沉积和化石记录发育良好,是中国苗岭统的经典研究区之一。前人已针对华北寒武系苗岭统乌溜阶腕足动物的系统古生物学开展了一系列基础工作,但这些相关研究主要集中于辽宁地区,目前对华北其他地区苗岭统乌溜阶腕足动物的研究程度仍然有限,相关生物地层学也有待进一步探索。本文首次系统描述了山东潍坊寒武系苗岭统乌溜阶馒头组上部碎屑岩中的腕足动物,共鉴定出舌形贝型亚门4属5种,包括馒头组洪河段的舌孔贝未定种Lingulellotreta sp.indet.以及馒头组上页岩段的山西小舌形贝Lingulella shansiensia(Walcott,1905)、德姆斯小舌形贝Lingulella damesi (Walcott,1905)、伊瑞克乳房贝Acrothele eryx (Walcott,1905)和东方原孔贝Prototreta orientalis(Resser and Endo,1937)。值得注意的是,在馒头组上页岩段的3层岩性略有差异的泥岩中,分布着3层完全不同的腕足动物,共有4种,但这3个组合都位于Bailiella lantenoisi带这一三叶虫生物带。腕足动物组合在极短时间内的快速交替现象,表明了腕足动物对环境背景的微弱变化具有较强的响应。     

辽东寒武纪三叶虫Redlichia (Pteroredlichia) murakamii Resser et Endo的蜕壳

华北辽东本溪寒武纪三叶虫Redlichia(Pteroredlichia)murakamii蜕壳标本完好地保存了头盖向下翻转的蜕壳状态,为寒武纪Redlichia的蜕壳模式提供了新的视角。此标本自由颊未保留,胸尾相连,头盖与胸部分离,头盖向下翻转,基本保持原位,为原地埋藏的蜕壳标本。蜕壳过程如下:面线裂开,头盖耸起卷曲并翻转,与胸部分离,胸部扭动,虫体摆脱老壳向前爬出。此蜕壳方式在McNamara(1986)报道的澳大利亚寒武纪Redlichia的蜕壳类型中并未出现。     

朝鲜南部的Pseudogl yptagnostus(三叶虫)并论朝鲜寒武纪斜坡相的意义

朝鲜南部Ｍａｃｈａｒｉ组Ｏｌｅｎｏｉｄｅｓ带的Ａｇｎｏｓｔｕｓ（Ｐｔｙｃｈａｇｎｏｓｔｕｓ？）ｏｒｉｅｎｔａｌｉｓ Ｋｏｂａｙａｓｂｈｉ一种应归于Ａｇｎｏｓ－ｔｏｔｅｓ（Ｐｓｅｕｄｏｇｌｙｐｔａｇｎｏｓｔｕｓ）Ｌｕ,１９６４一属,时代是晚寒武世长山期,不是早期中寒琥世,小林贞一的Ｏｌｅｎｏｉｄｅｓ带是中及晚寒武三叶虫混杂在一起的一个化石带。他建立的该组５个化石带也有问题。Ｃｏｒｅｏｌｅｎｕｓ,Ｃｈ     

湘西晚寒武世多节类三叶虫新种及Erixanium属首次发现

文中描记 3个多节类三叶虫新种 :Hardyoidesdamaensissp .nov .,Meringaspisdamaensissp .nov .,andRhyssometopus (Rostrifinis)nitidussp .nov .,均产自湘西凤凰花桥组中部。同时描记首次在江南斜坡带中发现的Erixanium一属的保留命名种Erixaniumcf.E .sentum。Erixanium是全球性分布的多节类三叶虫 。     

Middle and Upper Cambrian Protoconodonts and Paraconodonts from Hunan, South China

More than 4200 kg of limestone, representing 980 productive samples, from the upper Middle Cambrian, Upper Cambrian, and lowermost Ordovician in western and north-western Hunan were processed for paraconodonts, protoconodonts, and euconodonts. The focus of the present paper is on the upper Middle and lower Upper Cambrian interval as it is developed at two, apparently stratigraphically continuous, key sections. The collections studied, which include more than 20,000 specimens and are quite diverse taxonomically, prove that some protoconodonts and paraconodonts are useful biostratigraphically. Previously proposed protoconodont-paraconodont biozones in Hunan are revised and correlated with recently revised trilobite biozones, as well as with protoconodont-paraconodont and trilobite biozones in North China. Twenty-six species and seven conditionally identified species belonging to 13 genera are described. Among these, two genera ( Huayuanodontus and Yongshunella ) and two species ( Westergaardodina elegans and Yongshunella polymorpha ) are new. This study has special interest for Cambrian biostratigraphy because the two studied sections are global stratotype candidates for the Middle-Upper Cambrian series boundary. The level of the Upper-Middle Cambrian Series boundary, as currently recognized in China (at the base of the Linguagnostus reconditus Trilobite Biozone) is well marked in the paraconodont succession and can be traced into the Swedish standard succession using these fossils. By contrast, another level recently proposed as a potential global Middle-Upper Cambrian Series boundary level, the base of the Glyptagnostus reticulatus Trilobite Biozone, does not coincide with any marked change in the Hunan conodont species succession useful for local and regional correlation.     

The North China Steptoean Positive Carbon Isotope Event: New insights towards understanding a global phenomenon

Precise biostratigraphic correlation of the base of the Paibian Stage, Cambrian, within and beyond the North China craton has been difficult, mostly because of the strong endemism of the trilobite fauna on the shallow platform facies. The use of the Steptoean Positive Carbon Isotope Excursion (SPICE) in defining the Guzhangian-Paibian stage boundary has become a standard practice. Thus, a chemostratigraphic study of the Huangyangshan section from North China has been carried out. This section in Shandong Province clearly records the SPICE, with the most detailed fossil and carbonate carbon isotope data to date. Compared to other sections in the world, all the published SPICE in North China display both reduced peak and reduced difference (Δ¹³C) values. These may imply unique conditions on the North China craton during the upper Guzhangian to Paibian stages. This study shows that the SPICE is recorded in relatively condensed sections in North China; thus, ≤ 0.5 m sampling density is suggested here in order to evaluate the presence of the SPICE in North China and condensed sections.     

Biostratigraphy of the Peri-Gondwana Cambrian trilobite fauna (northern Kerman,Iran) and correlation with other countries

Polymeroid trilobite fauna from two stratigraphic sections (Godbondar and Kuhbanan) of the Kuhbanan Formation in northern Kerman (central Iran) were studied and subjected to biostratigraphic analysis. Eleven genera and species are recognised from the latest Early Cambrian and Middle Cambrian Peri-Gondwanian successions of the study sections. The recognised fauna includes Afghanocare lategenatum, Blountia blountia, Iranoleesia sp., Iranoleesia pisiformis, Kermanella kuhbananensis, Kermanella lata lata, Kermanella lata minuta, Kermanella sp., Redlichia chinensis, Redlichia noetlingi and Redlichia sp. Based on trilobite distribution, three trilobite biozones were recognised in the study sections, namely Redlichia noetlingi biozone, Kermanella kuhbananensis biozone and Iranoleesia pisiformis biozone. The age of the study sections is late Early Cambrian to late Middle Cambrian based on the recognised trilobite biozones. The recognised late Early Cambrian trilobite assemblages (especially Redlichia and Kermanella) from northern Kerman are similar to those found from some other parts of Gondwana or Peri-Gondwana terrains (north India, Pakistan, northwestern Kashmir, Tajikistan, South Australia, South China and Afghanistan) and show affinities with fauna found in some other parts of Iran (Alborz, northern Iran; Tabas, eastern Iran; southeast Karman).     

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。     

EDIACARAN AND CAMBRIAN INDEX FOSSILS FROM SONORA, MEXICO

Abstract:  The Cambrian index fossil Treptichnus pedum is reported from the Puerto Blanco Formation near Pitiquito, Sonora, Mexico, and new occurrences of the Neoproterozoic index fossil Cloudina are reported from the underlying La Ciénega Formation. Considered together, these fossils constrain the location of the Ediacaran/Cambrian boundary in Mexico. The suite of fossils in this sequence is important because it provides an independent biostratigraphic datum for constraining the position of Laurentia during the onset of metazoan diversification, for testing proposed lithostratigraphic correlations among western North American Neoproterozoic–Cambrian successions, and for testing regional tectonic paradigms such as the Mojave-Sonora Megashear hypothesis.