共查询到20条相似文献，搜索用时 31 毫秒
1.
YU Wen 《《地质学报》英文版》2014,88(4):1262-1287
Yangtzeconus priscus-Archaeospira ornata, an important earliest Cambrian benthonic Assemblage of the Yangtze micromolluscan fauna, occurs mainly in the Lower Cambrian Zhongyicun and Dahai Members of the Yuhucun Formation in E Yunnan, the Tianzhushan Member （=Huangshandong Member） of the Dengying Formation in W Hubei and the Maidiping Member of the Hungchunping Formation in C Sichuan, China. About 90% of the genera of this Assemblage are unknown from the Nemakit-Daldynian and Tommotian molluscan Assemblages of the Siberian Platform, Russia. About 90% of the Siberian molluscan genera do not occur in the Zhongyicun and Dahai Members in the Meishucun section and in the corresponding beds of the Yangtze Platform, because the Tommotian molluscan Assemblage is characterizedly abundant archaeocyathids. It is clearly indicated that the Yangtze and Siberian molluscan Assemblages represent different bio- and lithofacies and ages. The age of the pre-trilobitic Yangtzeconus priscus-Archaeospira ornata Assemblage is older than that of the Nemakit-Daldynian and Tommotian molluscan Assemblages and referable to the Earliest Cambrian. Two new genera Mcnamaraconus and Zhangwentangoconus are herein proposed. 相似文献
2.
New Vetulicoliids from the Lower Cambrian Guanshan Fauna, Kunming 总被引：13，自引：3，他引：10
LUO Huilin FU Xiaoping HU Shixue LI Yong CHEN Liangzhong YOU Ting LIU Qi Yunnan Institute of Geological Science Kunming Yunnan Shenzhen Palaeontological Museum Shenzhen Guangdong Faculty of Earth Science China University of Geosciences Wuhan Hubei 《《地质学报》英文版》2005,79(1):1-6
3.
A New Arthropod, Guangweicaris Luo, Fu et Hu gen. nov. from the Early Cambrian Guanshan Fauna, Kunming, China 总被引：2，自引：2，他引：0
LUO Huilin FU Xiaoping HU Shixue LI Yong HOU Shuguang YOU Ting PANG Jiyuan LIU Qi 《《地质学报》英文版》2007,81(1):1-7
The Guanshan Fauna is a soft-bodied fauna dominated by arthropods （including trilobites, trilobitoides, Tuzoia, Isoxys, and bradorids） in association with priapulids, brachiopods, anomalocaridids, vetulicoliids, sponges, chancellorids, and echinoderms. This paper reports and describes a new arthropod from the yellowish green mudstone at the lower part of the Wulongqing Formation, Canglangpuan Stage, Lower Cambrian in Kunming, Yunnan, China. The stratigraphic and geographic distribution, classification, fossil preservation, life style of this new arthropod and comparisons with other fossil arthropods are also discussed in details. The discovery and research of the non-mineralized arthropod, Guangweicaris Luo, Fu et Hu gen. nov. from the Guanshan Fauna adds new members to the taxonomic list and provides new information to the evolution of early arthropods. Furthermore, this study would shed new light into the ＂Cambrian Explosion＂ and the evolution of early life. 相似文献
4.
V. A. Luchinina I. V. Korovnikov N. V. Novozhilova D. A. Tokarev 《Stratigraphy and Geological Correlation》2013,21(2):131-149
The Early Cambrian history of the development of the Siberian Platform was marked by events of global significance. In the Early Cambrian the Siberian Platform was the centre of appearance of the first shelly fossils. For this reason, paleobiogeographical features of the distribution of fossils are of interest for scientists as a tool for paleogeographic and paleogeodynamic reconstructions. An analysis of changes in the Early Cambrian biota taxonomic diversity allowed us to reveal two major stages in its development: (1) Late Vendian (Tommotian and Atdabanian Stages): spreading of the Siberian biota worldwide; (2) Late Botomian-Toyonian Stages: an increase in the degree of endemism, extinction of archeocyaths, reduction in organogenic structures, deposition of black shales, and flourishing of trilobites. A permanent increase in the degree of biota endemism, which reached its maximum in the Botomian Stage, and the first appearance of migrants at the generic and species level at the same time, coincided with the first major transgressive phases. The study of the geographic distribution of diverse groups of the Early Cambrian fauna and calcareous algae of the Siberian basin allowed us to identify a number of biofacies of different age, whose boundaries do not coincide. The evolution and change in the taxonomic composition of the Siberian basin biota were affected by events of the first (Salair) phase of the Caledonian orogeny, manifested in the Altai-Sayan region much earlier than in other parts of the world and influencing the geological history of the Siberian Platform. These events resulted in the extinction and appearance of some specific groups of the Tommotian fauna in the Siberian Platform. 相似文献
5.
《International Geology Review》2012,54(8):1108-1113
Three new genera and four species of trilobites are described which include Tchaispis sdzuyi Atopina antiqua, Ivshiniellus nikolaii, and I. patulus. On the basis of their lack of eyes, configuration of cranidium, outline and segmentation of the glabella, very wide fixed cheeks and character of the anterior border they are assigned to the family Conocoryphidae Angelin, 1854. Tchaispis is known from the Middle Cambrian Olenek horizon of the Siberian Platform. Atopina and Ivshiniellus are known from the Lower Cambrian, Aldanian Stage of Tuva. --R. A. Robison. 相似文献
6.
Cryptalgal-metazoan bioherms of early Ordovician age in the St George Group, western Newfoundland 总被引：3，自引：0，他引：3
Bioherms are common in the St George Group, a sequence of shallow-water carbonate rocks deposited on the western continental shelf of Iapetus Ocean. They range from small heads and metre-sized mounds to extensive banks and complexes many metres thick and hundreds of metres in lateral extent. The cores of these bioherms are principally composed of thrombolites (unlaminated, branching, columnar stromatolites), structures quite distinct from laminated stromatolites which are common in intertidal beds. Associated with thrombolites is a diverse fauna of burrowing invertebrates, trilobites, nautiloids, pelmatozoans, brachiopods, gastropods, rostroconchs and archaeoscyphiid sponges. On the basis of framework-building components, three main bioherm types are distinguished: (1) thrombolite mounds, (2) thrombolite-Lichenaria or -sponge mounds and (3) thrombolite-Lichenaria-Renalcis reef complexes. The framework of the last is the most complex, with abundant cavities and a demonstrably uneven growth surface of thrombolites, corals and free-standing Renalcis heads, walls and roofs. Some cavities were active sediment conduits while others were protected, their roofs draped with Renalcis and their walls coated by cryptalgal laminites. These bioherms possess the attributes of shallow-water ecologic reefs. They span a critical time gap in the development of reefs, the transition period from algal-dominated bioherms of the Precambrian and Cambrian to the metazoan-dominated bioherms of the Middle Ordovician and remaining Phanerozoic. 相似文献
7.
Brachiopods, a group of benthic suspension-feeding marine invertebrates, made their first appearance in the Lower Cambrian. In the Yangtze Platform (South China), well-exposed Lower Cambrian stratigraphic succession represents shallow to deeper water environments. Strata from eastern Yunnan, southern Shaanxi and the Yangtze gorges areas of western Hubei Province, deposited in muddy-siltstone and carbonate lithofacies, contained an abundant variety of brachiopods, including all the representatives of the subphylum Linguliformea and the calcareous-shelled genera of Kutorgina and Nisusia from the subphylum Rhynchonelliformea. Thus the fossil assemblage bears witness to the first major phase of evolutionary radiation of brachiopods during the ‘Cambrian explosion’ interval of metazoans. Brachiopods from the celebrated Chengjiang fauna have exquisitely preserved soft-tissues, which reveal the body plans and evolutionary acquisition of morphological novelties of the early stocks, and also provide a good opportunity for testing the analogies with the stem groups from the extant representatives. These fossils have corroborated the view that brachiopods developed complex organization of tissues, and achieved considerable evolutionary success already by the onset of ‘Cambrian Explosion’. Thus it is not improbable that a large part of this radiation occurred within, or only just before early Cambrian time. Studies of Chengjiang brachiopods suggest that attachment by a pedicle to the substrate was probably the most common relationship of Cambrian brachiopods with the substrate where they inhabited. 相似文献
8.
华南过渡区凯里组及同期地层的初步研究 总被引：23，自引：3，他引：23
<正> 凯里组为卢衍豪教授1963年所建,周志毅等(1980)详细工作后,面貌比较清楚。它是分布于贵州东部丹寨、台江、玉屏一带的以泥、页岩为主厚约300m的一套地层,属过渡区。化石丰富,以三叶虫Pagetia,Oryctocephalids,Ptychopariids最为发育,由下而上建立了4个三叶虫带。与滇东陡坡寺组对比,顶、底界线一致;与黔北扩大的高台组(周志毅等1980,278页)对比,顶界略高于高台组。时代暂定为中寒武世(周志毅等1979, 相似文献
9.
In western Tasmania, near Melba Flats, a basalt within the Serpentine Hill Complex is overlain unconformably by Dundas Group sediments (Hodge Slate). About 32 m above the unconformity, a siltstone contains agnostoid and polymerid trilobites that indicate correlation with the middle Cambrian Ptychagnostus punctuosus Zone (Drumian Stage of unnamed Epoch 3 of the Cambrian). This provides an upper limit of about 505.2–504.5 Ma to the emplacement of ultramafic allochthons in western Tasmania. Other fossils present include dendroids, inarticulate brachiopods, hyolithids, helcionellids and sponges. The widespread agnostoid trilobite Ptychagnostus affinis (Brøgger 1878) and the holocephalinid trilobites Meneviella and Holocephalina are recorded for the first time in Tasmania. 相似文献
10.
Stratigraphic Implications of Skeletal Microfossils from the Cambrian of Korea: A Preliminary Report
Byung-Su LEE 《《地质学报》英文版》2008,82(6):1152-1159
Diverse small shelly fossils and other associated fossils were recently recovered from the Cambrian Hanaeri section, southwestern Mungyeong, Korea. The fauna includes conoidal problematica, poriferans (sponge spicules), coeloscleritophorans (chancelloriids), brachiopods, monoplacophorans, trilobite (?) fragments, echinoderms, and conodonts. A preliminary assessment of faunal associations, stratigraphic implications, and the correlation of these skeletal fossils is given, based on occurrences of Actinotheca cf. mira (He), Microcornus sp., Torellela laevigata (Linnarsson), Torellela sp., Archiasterella quadratina Lee, Chancelloria sp., Lingulella sp., Prototreta sp., Phakelodus tenuis (Müller), Phakelodus elongates (An), Hertzina sp., and Furnishina sp. 相似文献
11.
《International Geology Review》2012,54(8):1368-1373
Generally, the Olenellus -bearing beds and associated fauna have been regarded by Russian geologists as occurring in the upper one-third of a continuous sedimentary sequence which was unfossiliferous below and which rested on crystalline basement. Presumably early fossil groups began producing carbonate skeletal material at different times and migrated so as to arrive in various areas earlier or later than elsewhere. Hence, paleontological identification of the Lower Cambrian boundary requires knowledge, now lacking, of vertical distribution of the skeleton-producing organisms, of the conditions of their emergence, and of related sedimentary facies. Previously used physical criteria for the recognition of the Cambrian-Precambrian boundary are unsatisfactory. It is suggested that this boundary be determined by absolute dating. The author reviews recent findings on geologic age, absolute age, and faunal content of many formations in the Siberian Platform and adjacent regions that bear on this problem. — C. G. Tillman. 相似文献
12.
V. P. Rodionov 《Stratigraphy and Geological Correlation》2016,24(5):464-485
The available paleomagnetic data on the Verkhnyaya Lena Group from different areas of the southern Siberian Platform are revised. The group rests unconformably upon the Lower Cambrian strata and is overlain by Lower Ordovician rocks, which determines conditionally the age of its red-colored deposits. Paleomagnetic correlation of composite sections through the region using defined zones of normal and reversed magnetic polarity serves as a basis for development of the magnetostratigraphic scale for the Verkhnyaya Lena Group. The scale includes nine magnetic zones, which play the role of markers; seven of them are traceable in all the examined sections of the southern Siberian Platform. By the distribution of zones with normal (N) and reversed (R) polarity, the magnetostratigraphic scale is subdivided into three parts. Its lower part is represented by reversed polarity, which is characteristic of the second half of the Lower Cambrian. The middle part is characterized by frequently alternating zones with normal and reversed polarity corresponding to the Middle Cambrian. The upper part of the scale corresponds to the interval of reversed polarity characteristic of the Upper Cambrian and Lower Ordovician. The Middle–Upper Cambrian boundary is located near the last N–R reversal of the geomagnetic field in the Cambrian. The magnetostratigraphic scale includes nine orthozones united into three superzones, which are attributed to two hyperzones of magnetic polarity. 相似文献
13.
吉林中部志留─泥盆纪生物地层、群落生态及生物古地理 总被引：7，自引：1，他引：7
吉林省中部的二道沟组、小绥河组、张家屯组的时代归属，一直是国内、外地质学家争议的问题之一。根据无脊椎动物化石鉴定结果，张家屯组的时代为志留纪Ｌｕｄｌｏｗ晚期至Ｐｒｉｄｏｌｉ早期，小绥河组为志留纪末Ｐｒｉｄｏｌｉ期或泥盆纪初Ｌｏｃｈｋｏｖ期，二道沟组为早泥盆世Ｌｏｃｈｋｏｖ早期。根据上述地层中珊瑚和腕足动物化石，推测它们当时是生活在正常浅海的生活环境中，大致相当于底栖组合ＢＡ３。我国东北地区中古生代存在着两个不同的动物地理区：华北地台北缘产Ｒｅｔｚｉｅｌｌａ腕足动物群和Ｃａｒｌｉｎａｓｔｒａｅａ珊瑚动物群，吉林中部就位于这一个动物地理区范围之内；西伯利亚地台南缘产Ｔｕｖａｅｌｌａ腕足动物群。 相似文献
14.
吉林省中部的二道沟组、小绥河组、张家屯组的时代归属，一直是国内、外地质学家争议的问题之一。根据无脊椎动物化石鉴定结果，张家屯组的时代为志留纪Ｌｕｄｌｏｗ晚期至Ｐｒｉｄｏｌｉ早期，小绥河组为志留纪末Ｐｒｉｄｏｌｉ期或泥盆纪初Ｌｏｃｈｋｏｖ期，二道沟组为早泥盆世Ｌｏｃｈｋｏｖ早期。根据上述地层中珊瑚和腕足动物化石，推测它们当时是生活在正常浅海的生活环境中，大致相当于底栖组合ＢＡ３。我国东北地区中古生代存在着两个不同的动物地理区：华北地台北缘产Ｒｅｔｚｉｅｌｌａ腕足动物群和Ｃａｒｌｉｎａｓｔｒａｅａ珊瑚动物群，吉林中部就位于这一个动物地理区范围之内；西伯利亚地台南缘产Ｔｕｖａｅｌｌａ腕足动物群。 相似文献
15.
S.K. Shah 《Precambrian Research》1982,17(2):87-98
The biostratigraphy of the Cambrian of Kashmir based on trilobite assemblage zones and trace fossils has been attempted. Faunal gaps occur in lower part of Lower Cambrian, upper Lower Cambrian, lower Middle Cambrian and upper part of Upper Cambrian. In the Lower Cambrian Cruziana—Rusophycus and Redlichia Zones, in the Middle Cambrian Solenopleura—Tonkinella, Tonkinella—Anomocare, Anomocare—Bailiella and Bolaspidella Zones, and in the Upper Cambrian Chuangia and Dikelocephalites Zones are recognized. The position of intrasystem boundaries is also discussed. While the various taxa have lithological preferences and are not necessarily found in a continuous sequence, an attempt has been made to interpret the ranges of different genera. The affinities of the fauna with that of other Cambrian basins of the world are discussed. It is concluded that the bulk of the fauna is of a cosmopolitan nature. 相似文献
16.
Definition of early Cambrian chronostratigraphic boundaries is problematic with many subdivisions still awaiting ratification. Integrated multi-proxy data from well-resolved regional-scale schemes are ultimately the key to resolving broader issues of global correlation within the Cambrian. In Australia, early Cambrian biostratigraphy has been based predominantly on trilobites. Phosphatic shelly fauna have great potential as biostratigraphic tools, especially in pre-trilobitic strata because they are widespread and readily preserved, but they have remained underutilised. Here we demonstrate their value in a new biostratigraphic scheme for the early Cambrian of South Australia using a diverse shelly fauna including tommotiids, brachiopods, molluscs and bradoriids.Biostratigraphic data are derived from ten measured stratigraphic sections across the Arrowie Basin, targeting Hawker Group carbonates including the Wilkawillina, Wirrapowie and Ajax limestones and the Mernmerna Formation. The stratigraphic ranges of shelly fossils are predictable and repeatable across the Arrowie Basin, allowing three discrete shelly biozones to be identified, spanning Terreneuvian, Stage 2 to Series 2, Stages 3–4. The Kulparina rostrata Zone (new) and part of the overlying Micrina etheridgei Zone (new) are pre-trilobitic (predominantly Terreneuvian). The Cambrian Series 2, Stage 3 Dailyatia odyssei Zone (new) features a very diverse shelly fauna and will be described in detail in a separate publication. These zones provide robust means to correlate Terreneuvian–Series 2 successions in neighbouring coeval basins in Australia, particularly the Stansbury Basin. Wider correlation is possible throughout East Gondwana, and especially with South China. 相似文献
17.
I.V. Korovnikov D.A. Tokarev N.V. Novozhilova A.A. Terleev 《Russian Geology and Geophysics》2018,59(2):186-192
The lower Ust’-Kundat Formation has been studied in detail in a section along the Kiya River (Kuznetsk Alatau, Altai-Sayan folded area). The section was deposited during the Tommotian stage and is a stratotype for the Lower Cambrian Ust’-Kundat sequence comprising several members of the Ust’-Kundat Formation. Member 2 contains newly discovered and previously known species of archaeocyathids near its top found stratigraphically lower than the oldest known archaeocyathan assemblage of the Nochoroicyathus mariinskii biozone. The found archaeocyaths cannot be dated precisely and may have either Tommotian or Atdabanian ages. Small shelly fossils from the same section cover a large stratigraphic range as well. The findings call for updating the age of the upper Ust’-Kundat sequence and the Tommotian upper boundary in the regional stratigraphy of the Altai-Sayan folded area. 相似文献
18.
V.V. Samsonov A.I. Larichev V.I. Chekanov V.V. Solov’ev 《Russian Geology and Geophysics》2010,51(11):1204-1218
The paper discusses modern views of the structure of the main producing plays in the southern Siberian Platform: Riphean, Vendian, and Lower Cambrian. The major zones of oil and gas accumulation have been distinguished. Forecast resources have undergone differentiated expert evaluation, and methods for their development have been recommended. 相似文献
19.
须腕动物门(Pogonophora)皱节虫科(Sabelliditidae)的化石(图版Ⅲ,图2)在前寒武纪和寒武纪沉积内均大量发现,最近此种化石还发现于苏联的中里菲界(约11亿年),被认为是一种可靠的最古老的后生动物化石。 相似文献
20.
Exceptionally preserved fossils,such as those from Cambrian Burgess Shale-type fossil-Lagerstatten are critical because of their unique contributions to knowledge of the phylogenetic radiation and palaeoecological expansion of metazoans during the Cambrian explosion.Critically,these deposits provide information that is usually unobtainable from shelly and skeletonized fossils alone.The Guanshan Biota(Cambrian Series 2,Stage 4)in the Yunnan Province of South China,has produced abundant and diverse,exquisitely preserved fossils that often retain soft tissues and organs.To date,most fossils from the Guanshan Biota have been collected from localities such as Gaoloufang and Gangtoucun,which have become inaccessible due to new urban expansions and constructions of residential buildings.Here we present the first report of soft bodied fossils from a new section at Kanfuqing,close to the Wulongqing village in Malong County,approximately 3 km east of the Wulongqing Formation stratotype section.Fossils retain soft morphology,and include brachiopods with delicate marginal setae,priapulids with well-preserved sclerites and vetulicolians with entire sections of body.In addition,this fauna includes rare occurrences of trilobites preserved with soft tissues replicated as pyrite pseudomorphs after weathering.This discovery represents an important palaeogeographical extension of soft-bodied fossils of the Guanshan fauna to the east of the Xiaojiang Fault(related to Tsinning tectonic movements ca.700 Ma).The fauna from the new Kanfuqing section is similar to that reported from the Wulongqing Formation west of the Xiaojiang Fault,and thus has significant implications for early Cambrian palaeogeography,faunal successions and palaeoenvironments of eastern Yunnan. 相似文献