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1.
Cambrian echinoderms,especially eocrinoids,have been reported recently from Guizhou and Yunnan provinces of China,such as the Kaili,Balang,and Guanshan faunas.The present paper reports abundant well-preserved eocrinoids from the Cambrian Mantou Formation of Dalian,Liaoning Province.This new discovery provides additional data on the early evolution of Echinodermata.It also gives us a clue as to where to seek the Cambrian soft-bodied fauna on the margin of the North China Platform.  相似文献   

2.
Abundant well-preserved large articulated sponge fossils and isolated spicules have been reported from the Early Cambrian Hetang Formation, southern Anhui Province. This unique epifaunal fossil assemblage dominated by articulated sponge fossils is called the Xidi Sponge Fauna. The sponge fauna lived in a quiet oxygenic environment below the storm wave base. Bloom of phytoplankton and rapid sedimentation rate resulted in the deposition of the black shales. Sufficient food supply, lack of other competitors, abundant ecological niches, and demand for oxygen during early Cambrian were in favor of the diversification and evolution of large sponges in the Early Cambrian.  相似文献   

3.
Lower Cambrian yolk-pyramid embryos from Southern Shaanxi, China   总被引:6,自引:0,他引:6  
TheCambrianexplosioniswidelyacceptedasthesuddenappearanceofnumerousbilateriananimalphylaatornearthebeginningofCambriantime[1,2 ] .The 5 30 million year oldMaotianshanShalefaunacontainstheoldestgoodwhole bodyfossilsofbilateri ans,documentinganincreasingnumberofpresent dayanimalphyla[3,4 ] orsubphyla[5] (evenincludingvertebrates[6~ 8] aswell)knownfromLowerCambri an .ThebeginningoftheCambrianperiodisdatedat5 43millionyearsago ,whenthefirstlargeandelabo ratefossilburrowstogetherwiththemicrosco…  相似文献   

4.
澄江化石库中川滇虫属化石的新信息   总被引:2,自引:0,他引:2  
目的 对澄江化石库中数量可观的软躯体化石卵形川滇虫(Chuandianella ovata)的形态以及生态进行研究。方法 运用解剖学、形态比较学方法。结果 扩展性描述了该属种动物身体的内部构造;对该属种壳表装饰、尾扇结构等形态描述进行了修正;首次得出卵形川滇虫不属于瓦普塔虾科(Waptiidae)的结论;结合形态、功能及生态之间的联系引出了卵形川滇虫生活的方式及古环境。结论 川滇虫是一种生活于浅海底部的自由游泳者,以植物或浮游生物为食,在进化程度上稍低于瓦普塔虾。  相似文献   

5.
The Xiaoyang section, located in Zhenba County of Shaanxi Province, is important both for documenting the biodiversity of the Qiongzhusian Stage (Lower Cambrian) and for analyzing lithofacies-biofacies links in carbonate depositing environments on the Yangtze Platform.The skeletal fossils from the Xihaoping Member, including linguloid valves, cambroclavid and chancelloriid sclerites, genal and occipital spines of polymerid trilobites, and tubular fossils, are described here as the Eoobolus-Cambroclavus fauna, which mainly occurred in peritidal environments.The fossils from the argillaceous limestones of the lower Shuijingtuo Formation, containing lingulate brachiopods, eodiscoid trilobites, bivalved arthropods, microdictyoniid sclerites and siliceous sponge spicules, are regarded as the Palaeobolus-Hupeidiscus-Kunmingella fauna, which presumably lived in subtidal or deeper water environments.The faunal diversity in the Xihaoping Member is lower than that in the lower Shuijingtuo Formation.The investigations of the skeletal fossil assemblages from carbonate lithofacies in southern Shaanxi will significantly contribute to a detailed documentation of the biodiversity during the Qiongzhusian interval on the Yangtze Platform and add new knowledge on the Cambrian bioradiation.  相似文献   

6.
目的 系统分析滇东泥质基底澄江化石库腕足动物的生活方式.方法 依据澄江化石库丰富的腕足动物资料,论证寒武纪早期泥质基底腕足动物的生活策略.结果 寒武纪早期泥质基底上腕足动物的生活方式主要包括肉茎附着型(pedicle-anchoring or pedicle-attaching)、自由平躺型(free-lying)、假内栖型(qusi-infaunal)和表栖粘附型(cemented epifaunal),肉茎附着型是早寒武世腕足动物生活的最普遍的型式.结论 空间生态分析显示,早寒武世滇东海盆中,腕足动物的分布已经具有一定的空间层次性,不同的腕足类型占据了不同的生态位,形成了比较复杂的空间群落结构.  相似文献   

7.
贵州遵义下寒武统牛蹄塘组生物群中的海绵化石   总被引:10,自引:0,他引:10  
遵义松林中南村下寒武统牛蹄塘组中下部,特别是下部黑色泥岩中产有大量的海绵骨针,形态多样,初步研究有多达10属以上的海绵动物,与澄江生物群的海绵相比,牛蹄塘组的海绵动物化石其组合特征以六射海绵动物为主,它的发现增添了寒武纪生物组成的信息,为海绵动物从晚新元古代的发生以至穿越寒武纪的演化过程及寒武纪生物大爆发的定性,量度提供了重要信息及资料,描述了4属2个种。1个相似种和1个未定种。Hyalosinica sp.;Saetaspongia densa Mehl et Reitner,1993;Leptomitus teretiusculus CHen,Hou et Lu.1989;Crumillospongia cf.biporosa Righy,1986,它们分属于海绵动物的六射海绵纲和普通海绵纲。  相似文献   

8.
Samples of black rock series collected from the Lower Cambrian Niutitang Formation, northwestern Hunan Province, China, were analyzed for trace elements.The trace element geochemical characteristics of the ore layer (high enrichments of Ni, Mo, V, U, Cu, Pb, Zn, Cd, Tl and Ba; high U/Th ratios and LREE-enriched patterns with positive Eu and Y anomalies) support the assumption that the Ni-Mo polymetallic layer is of submarine hydrothermal origin.High field strength elements (HFSE) and lithophile elements such as Nb, Ta, Zr, Hf, Li, Be, Rb, Cs, Th and Sc are remarkably higher in the upper unit than those in the lower unit of the Niutitang Formation.These features may reflect that hydrothermal contributions were diminished, and terrigenous constituents were increased in the sediments of the upper unit of the Niutitang Formation.  相似文献   

9.
Phosphorites occurring at the bottom of the Cambrian system contain abundant small shelly fossils, which are the product of the first episode of life explosion in the Cambrian. It was previously reported that the small shelly fossils are dominated by hyolithids, olivooids, zhijinitids, conodontomorphs, yubelichitids, camenitids and algae, with minor amounts of sponge fossils. Large amounts of sponge spicules, diverse in form, have been found for the first time in the Gezhongwu Formation phosphorites at Shixing, Zhijin County, Guizhou Province, of which such spicules as diaxon-triactins, diaxon-tetractins, pentaxon-pentactins and hexon-hexactins account for 30%. These spicules constitute the sponge clastic phosphorites made up of sponge clastics. Meanwhile, it is also expected that the radiation and diversity of sponge animals started as early as in the earliest Early Cambrian. Habit and burying environment of sponge animal are discussed in the paper.  相似文献   

10.
四川盆地中部龙王庙组储层成岩作用   总被引:1,自引:0,他引:1  
四川盆地中部地区下寒武统龙王庙组是油气勘探研究的重点层位。根据钻井资料、测井数据、岩心观察、普通薄片、铸体薄片、阴极发光、碳氧稳定同位素和主元素等分析,对龙王庙组储层成岩作用进行了研究,结果表明为颗粒白云岩和晶粒白云岩是龙王庙组主要的储集岩性,成岩作用主要有建设性、破坏性和保持性。建设性成岩作用主要包括溶蚀、破裂和烃类(有机酸)充注作用,破坏性成岩作用主要包括压实和压溶作用,保持性成岩作用主要包括胶结、白云石化和泥晶化作用。揭示了颗粒滩微相是龙王庙组优质碳酸盐岩储层发育的基础条件,海水白云石化、准同生期淡水溶蚀和烃类(有机酸)充注作用是优质储层形成的关键因素。  相似文献   

11.
贵州、云南寒武系底部磷块岩发育,是我国主要的含磷层位。然而,两个地区之间磷块岩沉积特征及成磷期次缺少对比,制约了云贵地区寒武系磷块岩的成磷规律的研究。为此,在对云南宁华、会泽和贵州织金磷块岩沉积特征对比的基础上,分析了寒武系磷块岩的沉积序列、成磷期次,提出富磷层位往往发育在海侵序列的晚期;而在海侵早期,虽然有大量的磷质供给,但由于同时供给的硅质、泥质也丰富,环境变化强烈,往往沉积纹层状、条带状磷块岩,其磷块岩品位低。海侵晚期,海岸环境相对稳定,又有大量磷质供给,高能环境对含磷沉积不断改造,磷质进一步富集,形成富磷的碎屑状磷块岩。因此,古地理位置、海侵序列发育对磷块岩具有重要的控制作用。根据扬子区古地理、织金地区含磷岩系厚度变化规律、沉积层序特征,认为贵州盘县-水城地区和织金-金沙地区是磷矿远景区。  相似文献   

12.
Despite a long history of research on the Early Cambrian in China most available data on small skeletal fossils concern fossil associations of the shallow carbonate platform. Information on skeletal fossils from marginal shelf environments of the Yangtze Platform is scanty, which may reflect the rarity of fossils in deeper sedimentary environments but is also due to limitation of carbonate distribution and outcrops, difficulties in fossil extraction, and a general research focus on the Precambrian-Cambrian boundary beds on the carbonate platform. Here we present a documentation of Meishucunian to Qiongzhusian small skeletal fossils from the lower Hetang Formation and the chert unit at its base from the Jiangshan region, Zhejiang Province, representing a relatively deep shelf environment compared to the inner shelf region. The earliest association (Meishucunian) from the chert unit underlying the Hetang Formation is mainly characterized by the occurrence of Protohertzina anabarica, P. unguliformis, Fengzuella zhejiangensis, and Kaiyangites novilis, which differs somewhat in composition from SSF-associations of typical inner shelf deposits. The enigmatic skeletal fossil Fengzuella zhejiangensis, which exhibits an unusual secretional growth mode previously unrecognized from the Early Cambrian, is described in detail. A younger (Qiongzhusian) fossil association contains numerous arthropod remains, such as disarticulated spines of arthropods (Jiangshanodus- and Kijacus-type), which have previously been considered as conodont-like fossils, and bradoriid valves.  相似文献   

13.
云南已知蝗总科和锥头蝗总科昆虫3科14亚科92属225种(亚种),特有属20属(占21.74%),特有种138种(占61.33%);印度已知4科20亚科158属337种(亚种),特有属37属(占23.42%),特有种127种(占37.69%),此结果表明两地蝗虫区系成分特殊且复杂,云南的特殊性更为明显。丰富度分析表明云南蝗虫属级和种级阶元丰富度均大于印度。两地蝗虫区系成分同源性较小;共布成分以东洋区系成分为主,其次为非洲区系成分,古北区系成分最少。属级阶元的区系交流主要经由以下3条路线:印中亚界+印马亚界一印度亚界;非洲界一印度块体(或Cimmerian块体)一印中亚界+印马亚界;非洲界一欧亚大陆一东洋界。  相似文献   

14.
The Chengjiang fauna has played a pivotal role in our understanding of the origin and diversification of metazoans since its discovery in 1984. To date, this fauna has been documented as consisting of 121 genera with 140 species belonging to 24 phyla[1-27]. The geo- graphic distribution of the Chengjiang fauna has been expanded from Chengjiang County to eastern Yunnan Province including Haikou, Malong, Yiliang, Anning and elsewhere[25-33], with about 20 localities in to- tal[25,33]. Succes…  相似文献   

15.
为了查明浙江地区下古生界页岩气勘探前景,通过分析浙西北地区下寒武统荷塘组页岩有机质丰度、类型、成熟度等地球化学特征,矿物组成、孔隙度等物理特征及沉积、构造环境和分布情况,研究了荷塘组页岩气富集条件和勘探潜力.结果表明:研究区荷塘组页岩有机碳的质量分数为0.32%~4.24%,有机质丰富,生烃潜力较好;镜质体反射率在2.81%~4.83%,热演化程度高,处于过成熟阶段,有利于页岩气藏形成;页岩平均孔隙度为2.74%,微米级孔隙发育,有利于页岩气的储集;等温吸附实验的最大吸附量分别为3.5 m3/t和5.16m3/t,吸附甲烷能力良好;页岩脆性矿物的质量分数达76%~86%,有利于页岩气的压裂开采.荷塘组泥页岩在浙西北地区广泛分布,有效厚度为10~60 m,在中洲-昌化一带埋深适中,具备较好的勘探前景.  相似文献   

16.
2003—2005年作者对滇西横断山区的大理、丽江、怒江、迪庆、保山、德宏地区的蜘蛛资源进行了调查,采集了10000头蜘蛛标本,经过整理鉴定,分布于该地区的蜘蛛223种,隶属30科,114属,东洋区种类占42.60%、东洋区一古北区种类33.18%、特有种占22.42%,广布种占1.79%。  相似文献   

17.
Previous studies have evaluated acritarchs from the Balang and Pingzhai sections of the Early-Middle Cambrian Kaili Formation in east Guizhou, China. The results of these studies suggest that the acritarchs in these sections have potential biostratigraphic significance. More recently, 34 samples collected from 83m lower part of the Lower-Middle cambrian Kaili Formation in the Jianshan section of Chuandong, Guizhou Province were prepared for palynological analysis. Analysis of these samples revealed a distinct change in the acritarch assemblages at the bed, which was approximately 46m above the bottom of the Kaili Formation. These findings suggest a boundary represented by an important alteration of the ecological environment. In addition, the position of the acritarch biostratigraphic change is somewhat higher than the boundary between Cambrian Series 2 and Series 3 based on trilobites found in the same section. This indicates that the distinct change in acritarch assemblages is similar to the change in trilobite assemblages that occurs around the boundary between Cambrian Series 2 and Series 3. Therefore, acritarch biostratigraphy can provide data that can be used to define the base of Cambrian Series 3 in this region, and possibly worldwide.  相似文献   

18.
TheLowerCambrianblackshalesequenceoccursinSouthChinaalonganarc parallellinearbeltex tendingmorethan 16 0 0km .Theseorganic richblackshalesformedinvariousmarineenvironmentsandtypicallycontainhigheramountsofmolybdenum ,nickel,vanadium ,andanumberofothereconomical lyimportantmetalsthandoanyothersedimentaryrocks[1,2 ] .Therefore ,thestudyoftheseblackshaleshasnotonlypaleoceangraphicimplicationbutalsoe conomicsignificance .Marinesedimentssuchasblackshalearecom plexmixturesofdetritalphasesandseawat…  相似文献   

19.
Phosphatized and three-dimensionally preserved embryos and spherical fossils of metazoan recovered from the Kuanchuanpu Member, Dengying Formation in southern Shaanxi, China provide nice devel- opmental sequence for the studies of origination, taxonomy, phylogenic evolution and developmental biology of early animals. Ontogeny of these larva fossils has not been systemically studied mainly due to their poor preservation and limited identification. The Kuanchuanpu Member, predominated by phosphorites and cherts, yields phosphatized animal embryos, particularly those of Olivooides and Punctatus which have high resolution in fine structures and different ontogeny developmental stages. An ontogenetic sequence of the Punctatus is established mainly base on its developmental transitions from body part to oral one, which is perfectly consistent with the embryonic ontogeny sequence pro- posed by Bengtson and Yue (1997). Furthermore, a new genus Quadrapyrgites gen. nov is erected to receive a larva with tetraradial body plan.  相似文献   

20.
Large amounts of vermicular fossils and a minor amount of sponge animal fossils have been found in the Early Cambrian Xidashan Formation in the region of Quruqtagh, Xinjiang. Vermicular fossils are generally more than 50 mm long and 0.3?1.4 mm wide; their wrinkled lamellae are microfine with 3?10 pieces within the length of every each millimeter. The fossils are considered to be Sabellidites cambriensis Sokolov (1965). The Xidashan Formation is the highest stratum in which Sabellidites occur, as has been so far reported.  相似文献   

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