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1.
中国云南东部晋宁、江川地区的伊迪卡拉(震旦)系顶部灯影组旧城段新发现了多样的宏体化石群,除了丰富的Vendotaenia与Tyrasotaenia类化石以外,以形体较大的Tawuia类和Longfengshaniaceae科等具固着构造的底栖多细胞藻类化石占据优势,另有一些形态奇特、亲缘关系不明的宏体化石,该组合与华南陡山沱组和灯影组石板滩段的宏体化石组合相比存在着明显的差别。依据形态特征,本文概述了部分产自江川旧城段的具有不同类型固着构造的底栖藻类和归属不明的宏体化石特征。华南滇东地区旧城段形态多样的宏体藻类化石的发现,进一步表明伊迪卡拉纪末期存在后生植物的多样化发展。这一时期浮游微生物和后生植物的共同繁盛可能为早寒武世“澄江生物群”的爆发奠定了生态基础。  相似文献   

2.
A new macrofossil Lagerstatte was discovered from the uppermost Ediacaran Jiucheng Member at Jinning and Jiangchuan of the eastern Yunnan, yielding numerous diverse well-preserved thallophyte macrofossils. These include the previously-known representatives of vendobionts, Vendotaenia and Tyrasotaenia, and the biggish multicellular benthos such as Otuaria-like and Tawuia-like fossils, as well as Longfengshaniaceaens with diverse holdfast structures. There are still some other problematic macrofossils with peculiar configurations as well as uncertain relatives. The distinct dominance of the giant, unbranching thallophytes occasionally with holdfast structures distinguishes this assemblage from the other Ediacaran macrofossil Lagerstattes in the Doushantuo Formation at Miaohe, Wenghui and Lantian, and the contemporary assemblage in the Shibantan Member of Dengying Formation, Yangtze Gorges area. This paper outlines the characteristics of some of the multicellular macrofossils from the Jiucheng Member at Jiangchuan. They include some macrofossils with different types of holdfast structure, larger Chuaria-like and Tawuia-like morphology and questionable affinities as well. The discovery of greater diverse macrofossil assemblages from the Jiucheng Member of eastern Yunnan has further indicated that an important diversification and evolutionary radiation of metaphytes took place in the latest Ediacaran time. This radiation of large-scale, benthic metaphyte along with phytoplankton was likely important contributors to the early Cambrian explosion of metazoans.  相似文献   

3.
A new macrofossil Lagerstatte was discovered from the uppermost Ediacaran Jiucheng Member at Jinning and Jiangchuan of the eastern Yunnan, yielding numerous diverse well-preserved thallophyte macrofossils. These include the previously-known representatives of vendobionts, Vendotaenia and Tyrasotaenia, and the biggish multicellular benthos such as Chuaria-like and Tawuia- like fossiis, as well as Longfengshaniaceaens with diverse holdfast structures. There are still some other problematic macrofossils with peculiar configurations as well as uncertain relatives. The distinct dominance of the giant, unbranching thallophytes occasionally with holdfast structures distinguishes this assemblage from the other Ediacaran macrofossil Lagerstattes in the Doushantuo Formation at Miaohe, Wenghui and Lantian, and the contemporary assemblage in the Shibantan Member of Dengying Formation, Yangtze Gorges area. This paper outlines the characteristics of some of the multicellular macrofossils from the Jiucheng Member at Jiangchuan. They include some macrofossils with different types of holdfast structure, larger Chuaria-like and Tawuia-like morphology and questionable affinities as well. The discovery of greater diverse macrofossil assemblages from the Jiucheng Member of eastern Yunnan has further indicated that an important diversification and evolutionary radiation of metaphytes took place in the latest Ediacaran time. This radiation of largescale, benthic metaphyte along with phytoplankton was likely important contributors to the early Cambrian explosion of metazoans.  相似文献   

4.
我国南方伊迪卡拉(震旦)系陡山沱组页岩中,保存了以“庙河生物群”为代表的宏体碳质压膜化石群,以大量底栖固着的多细胞藻类为主,还包含推测的后生动物和海绵动物、可疑的遗迹化石等多门类生物化石,化石类型多样、分异显著,代表着新元古代“雪球”冰期之后和寒武纪早期后生动物大爆发前夕地球早期多细胞生物的一次大规模的进化辐射事件。本文通过比较湖北秭归庙河和贵州江口翁会两个典型产地的宏体化石优势属种的形态特征,以及两地所处的沉积古环境,分析探讨了这些优势类别与现生多细胞生物(包括红藻、褐藻和绿藻三大高级藻类)的亲缘关系。研究表明,寒武纪之前大约35~10 Ma间,各门类多细胞藻类广泛发育,与后生动物的先驱分子构成独特的古生态群落。  相似文献   

5.
华南伊迪卡拉纪"庙河生物群"的属性分析   总被引:4,自引:0,他引:4  
我国南方伊迪卡拉(震旦)系陡山沱组页岩中,保存了以"庙河生物群"为代表的宏体碳质压膜化石群,以大量底栖固着的多细胞藻类为主,还包含推测的后生动物和海绵动物、可疑的遗迹化石等多门类生物化石,化石类型多样、分异显著,代表着新元古代"雪球"冰期之后和寒武纪早期后生动物大爆发前夕地球早期多细胞生物的一次大规模的进化辐射事件。本文通过比较湖北秭归庙河和贵州江口翁会两个典型产地的宏体化石优势属种的形态特征,以及两地所处的沉积古环境,分析探讨了这些优势类别与现生多细胞生物(包括红藻、褐藻和绿藻三大高级藻类)的亲缘关系。研究表明,寒武纪之前大约35~10Ma间,各门类多细胞藻类广泛发育,与后生动物的先驱分子构成独特的古生态群落。  相似文献   

6.
A morphologically more diverse assemblage of Longfengshaniaceae has been found in the uppermost Ediacaran (Sinian) Jiucheng Member, Yuhucun Formation at Jinning and Jiangchuan, eastern Yunnan, South China. A majority of them are different from the Longfengshania found in the Neoproterozoic Changlongshan Formation, Yanshan Mountain area, North China and the Little Dal Group, North America. They are mainly characterized by a more varied, often thallus-like appearance with no branches, such as oval, pyriform, spindle, shovel, heart, ribbon and balloon shapes, and more sturdy stalk-like projection (stipe) with a smooth connection on the basal part of the thallus. In addition, they appear to have a remarkable attaching organ of lanceolate, shuttle-like or short stem-like structure at the base of the stipe. Six distinct morphological taxa are recognized, including one new genus, two new species and three conformis species. The characteristics of the family and the genus Longfengshania are further discussed in this paper. The new discoveries of these carbonaceous macrofossils identified as Longfengshaniaceae algae on the basis of the diagnostic forms and anastomosis patterns of their thalli and stipes demonstrate that an important evolutionary radiation of metaphytes took place in the last Ediacaran stage. The flourishing of the benthonic thallophytes attached to the substrate from eastern Yunnan and considered to be photosynthetic alga probably provided continuous nutritional habitats for the explosion and diversification of the Early Cambrian “Chengjiang biota”. Translated from Acta Geologica Sinica, 2006, 80(11): 1643–1649 [译自: 地质学报]  相似文献   

7.
贵州台江早—中寒武世凯里组的宏观藻类化石   总被引:7,自引:0,他引:7  
杨瑞东  赵元龙 《地质论评》1999,45(3):282-290
本文描述了贵州寒武纪凯里组中的宏观藻类化石7属12种,其中有6个新属10个新种;Bosworthia simulans,B.gyges,Eolaminaria grandis gen。et sp.nov。,E.perelegans gen。et sp。nov.,F.vein gen.et sp.nov.,Kailiphyton simulans gen.et sp.nov.,Palaeospine  相似文献   

8.
9.
贵州台江中寒武世凯里生物群古生态研究   总被引:1,自引:2,他引:1  
凯里生物群是世界三大布尔吉斯页岩型生物群之一。本文通过古生物个体埋藏保存情况、古生物个体生态学、沉积学和地球化学等的研究和分析,认为凯里生物群中大部分分子是从异地搬运到陆棚环境埋藏的。同时,提出了凯里生物群的埋藏机理模式和生态复原图。  相似文献   

10.
全球早、中寒武世藻类生物地理分区初探   总被引:1,自引:0,他引:1       下载免费PDF全文
澄江生物群、凯里生物群、加拿大布尔吉斯生物群和西伯利亚藻群中均有丰富的藻类化石。根据前寒武纪宏观藻类的分布以及凯里生物群和布尔吉斯页岩生物群中藻类和后生动物的相似性,讨论了前寒武纪至中寒武世期间生物地理分区的控制因素。对几个生物群中的藻类化石和后生动物化石的对比研究发现,在相近的纬度范围内, 动植物化石组合特征非常相似; 而纬度明显差异时, 藻类生物群及后生动物群也具有明显的差异。由于后生生物在前寒武纪至中寒武世期间具有低的演化程度和分异能力,因此生物地理分布的主要控制因素是古纬度。而Schopf (1976)的生物地理分区模式不适合这一时期的生物地理分区。结合前寒武纪至中寒武世后生生物化石的分布情况,建立了前寒武纪-中寒武世时期的生物地理分区模式。这个模式较好地解释了分布在北美大陆和华南大陆上的寒武纪生物群相似的原因。  相似文献   

11.
中国晚前寒武纪的宏体化石概观   总被引:6,自引:1,他引:6       下载免费PDF全文
陈孟莪 《地质科学》1989,62(3):244-255
本文综述了目前中国晚前寒武纪地层中所发现的宏体化石,从18亿年起直到6亿年左右。蓟县剖面高于庄组(14亿年)中发现Grypanta等大化石,再次证明生物演化大阶段的世界性。包括后生动物实体化石在内的淮南生物群可能是前冰期的,也就是先伊迪卡拉期的。震旦纪晚期的西陵峡生物群,现有伊迪卡拉期的典型分子,又有丰富的蠕虫管和高级的红藻、绿藻类。蠕虫管的大量出现预告了带硬部动物时代的到来。  相似文献   

12.
The term‘Ediacara Biota’(or many variants thereof)is commonly used to refer to certain megascopic fossils of Precambrian and early Palaeozoic age e but what does the term actually mean?What differentiates a non-Ediacaran‘Ediacaran’and an Ediacaran‘Ediacaran’from an Ediacaran non-‘Ediacaran’?Historically,the term has been used in either a geographic,stratigraphic,taphonomic,or biologic sense.More recent research and new discoveries,however,mean that the term cannot actually be defned on any of these bases,or any combination thereof.Indeed,the term is now used and understood in a manner which is internally inconsistent,and unintentionally implies that these fossils are somehow distinct from other fossil assemblages,which is simply not the case.Continued use of the term is a historical relic,which has led in part to incorrect assumptions that the‘Ediacara Biota’can be treated as a single coherent group,has obscured our understanding of the biological change over the PrecambrianeCambrian boundary,and has confused research on the early evolution of the Metazoa.In the future,the term‘Ediacaran’should be restricted to purely stratigraphic usage,regardless of affnity,geography,or taphonomy;suffcient terminology also exists where reference to specimens on a geographic,taphonomic,or biologic basis is required.It is therefore time to abandon the term‘Ediacara Biota’and to instead treat equally all of the fossils of the Ediacaran System.  相似文献   

13.
晚中生代时期华北东北部发育燕辽生物群、热河生物群和阜新生物群陆地生物群。它们的快速演变过程和华北克拉通上同时期发育的岩石圈减薄、大面积强烈岩浆活动、变质核杂岩及伴随的伸展盆地等地球表层重大地质事件并行发生,表现着地壳表层系统圈层间的相互作用和响应。生物群的繁盛与灭绝与地球表层大规模岩浆-火山活动(髫髻山组—张家口组和大北沟组—义县组)发育时代高度协同一致。地球表层重大地质事件直接或间接地控制或改造着地球表层古地理和古生态环境,生物群只得调整自身去适应环境和生态背景的改变。火山-岩浆活动改变着地质-生态环境,生物群都紧密联系多期次火山-岩浆活动,化石也都被埋葬在沉积-火山碎屑岩中。华北克拉通破坏重大地质事件发生响应于全球变化和统一地球表层系统。盆地沉积充填序列、特殊陆相环境沉积建造、特殊环境沉积物等记录了响应的古地理、古环境变化与响应。陆地生物群分布、演化、更替与精确定年,脊椎-无脊椎生物(化石)埋葬特征,生物演化速率、消长关系和生物群(组合)更替的形式和性质,以及脊椎动物骨骼、牙齿的常量、微量元素、H-B-C-N-O-S和C-O-Sr等地球化学特征的研究可以恢复和重建古地理、古生态环境和古生态系统。  相似文献   

14.
Charnwood Forest (UK) hosts some of the oldest and best-preserved macrofossils known from the Ediacaran. It is the counterpoint to the more widely studied fossil sites of south-eastern Newfoundland (Canada), which include the recently-designated UNESCO World Heritage Site of Mistaken Point. Discoveries made in Charnwood Forest since 2008 have the potential to revolutionise our understanding of the evolution of complex macroscopic life and the subsequent development of ‘modern’ (i.e. Phanerozoic) ecosystems. The sites in Charnwood include the holotypes for several iconic Ediacaran taxa, and potentially both the oldest and youngest representatives of the deep-water Avalon Assemblage. These communities provide a unique opportunity to test models of community ecology, biological endemism and environmental sensitivity and adaptability in the Ediacaran. Here, we review the geology of Charnwood Forest and the palaeobiology of its biotas, and we summarise recent scientific advances in the context of our developing understanding of early macroscopic life. We review the application of Reflectance Transformation Imaging to these ancient communities, and signpost exciting new directions for research in Charnwood Forest, almost 170 years after the fossils were first brought to light.  相似文献   

15.
贵州台江中寒武世凯里组中分枝状宏观藻类化石   总被引:6,自引:1,他引:6  
本文描述了贵州中寒武世凯里组中的分枝状宏观藻类化石5属7种,即:Marpolia spissa Walcott,Marpolia aequalis Walcott,Guizhouella ramulosa Yang(gen.et sp.nov.),Doushantuophyton lineare Chen,Thamnophton formosus Yang(gen.et sp.nov.),Eoulothrix fibrillata Ding,Eoulothrix flabellophyton Yang(sp.mov.)。根据大量的藻类与凯里生物群共生特征,从藻类的生态及生物群分布受到沉积韵律控制等特征分析,认为凯里生物群生活环境的水深应该在30-60m,而埋藏和保存环境的水深是150m左右。另外,将凯里生物群中的宏观藻类化石与震旦纪陡山沱期的藻类化石进行了比较,两者在以分枝状藻类占主要组成上是相似的,从这一方面来说,晚震旦世宏观藻类与寒武纪宏观藻类没有大的演变,但寒武纪宏观藻类以出现钙质珊瑚藻类、分枝更加复杂的类型和具有锯齿状叶状体、生殖托构造的藻类为特征。  相似文献   

16.
The Avalon biota (Ediacaran Period, 570–559 Ma) marks the first appearance of macroscopic and complex benthic communities in the fossil record. This assemblage is known from a few localities worldwide, mainly in Canada and England. Here, we report for the first time the presence of Ediacaran macrofossils in deposits of similar age from Gondwana (Itajaí Basin, southern Brazil). Our new radiometric date (~563 Ma) indicates that the Itajaí Basin can be chronocorrelated with the classic Avalonian deposits and thus represents one of the oldest records of the Ediacaran biota in Gondwana. We describe the presence of the Ediacaran genus Palaeopascichnus, as well as discs (Aspidella and Nimbia), and other problematic forms. Contrary to the deep-marine macroorganisms of the Avalon Assemblage, the Itajaí fossils are associated with abundant and exceptionally preserved three-dimensional microbial mats and microbially induced sedimentary structures (MISS) in relatively shallow settings (upper slope and distal delta front deposits). In this sense, the Itajaí biota could represent early adaptations of benthic macrobiota to the shallower and more photic environments that characterize the later White Sea Assemblage.  相似文献   

17.
The abundance and diversity of macrofossils in the Ediacaran have attracted much attention. The upper Doushantuo macrobiotas in South China, including the Miaohe biota from Hubei and the Wenghui biota from Guizhou, are mainly preserved as the carbonaceous compressions and dominated by macroscopic algae and metazoans. Here, we describe 10 genera and 10 species (including 6 new genera and species) of macrofossils from the Wenghui biota. At present, the Wenghui biota yields macrofossils in more than 31 genera and 33 species, excluding those given no image and established on a few unascertained specimens. Based on the occurrence and distribution of macrofossils in both Miaohe and Wenghui areas, the middle-late Ediacaran (back shales of the upper Doushantuo Formation) in South China can be subdivided into two assemblage biozones in biostratigraphy: (i) the Protoconites–Linbotulitaenia–Eoandromeda–Anomalophton assemblage biozone characterized by abundant and diverse macrofossils and by the ranges of Protoconites, Linbotulitaenia and Anomalophton; and (ii) the Baculiphyca–Gesinella–Cucullus–Beltanelliformis assemblage biozone characterized by the acme of the longer macrofossils Baculiphyca and Gesinella, and by few shorter and discoidal macrofossils.  相似文献   

18.
澄江生物群分子在贵州遵义牛蹄塘组发现   总被引:8,自引:1,他引:7  
澄江生物群是认识寒武纪生命大爆发的重要窗口,它的分布范围一直仅限于滇东地区,员近在贵州遵义松林牛蹄塘组底部页岩中发现有Naronia,Archotuba Conoidalis,Isaxys,Perpicaris,Lingulepis,Tsunyidiscus,Scenella,水母状化石(medusiform fossil),海绵动物化石Leptomitus,类似半索动物秆壁虫Rhabdopleura化石,软舌螺类Hyolithids,宏观藻类和疑源类化石Zunyiphyton perelegans Yang et Zhao,1999,Yuknessia sp.,Longenema Ding,1996,Sphaerocongregus variabilis等。其中有一部分是属于澄江生物群分子,这是云南省外澄江生物群分子的新发现。由于生物群之下40m处还产大量海绵动物、高肌虫和藻类化石等组成的松林生物群,其上又有下寒武统明心寺组古杯动物群,因此,这一生物群的发现对研究早寒武世生物的演化也具有一定的科学意义,同时,对澄江生物群的古生态学研究也具有重要意义。  相似文献   

19.
成都地质调查中心云南区调项目组2007年在罗平县中三叠统关岭组二段中发现了罗平生物群。罗平生物群是三叠纪的化石宝库,化石包含了脊椎动物和无脊椎动物。脊椎动物以海生爬行类和鱼类为主。无脊椎动物以节肢动物为主,伴生有双壳类、腹足类、菊石、棘皮动物、腕足类、牙形石、有孔虫和植物类化石。牙形石研究显示罗平生物群处于Nicoraella kockeli牙形石带,时代上属于中三叠世安尼期Pelsonian亚期。罗平生物群保存在一个局限的台盆环境中。其化石的特异保存很可能与底层水缺氧和微生物席的密封作用有关。罗平生物群目前是研究三叠纪海洋生态系统复苏的最好的一扇窗口,也是三叠纪海生鱼类和节肢动物化石保存最好的产地之一,为研究二叠纪末大绝灭后海洋生态系统复苏以及中生代海洋生态系统的演化历史提供了新材料。  相似文献   

20.
黔东北伊迪卡拉纪陡山沱组的宏体藻类   总被引:5,自引:0,他引:5  
王约  王训练  黄禹铭 《地球科学》2007,32(6):828-844
宏体生物广泛地生活于扬子地区伊迪卡拉纪陡山沱期的海洋中,它们为后生动物的快速发展和演化奠定了一个崭新的环境和一个新生态链的基础.产自于黔东北伊迪卡拉系陡山沱组的瓮会生物群生活环境应在贫氧的、透光性良好的浅海低能环境,以宏体藻类为主,共描述15属18种(其中包括3个新属、5个新种、2个修定属和4个修定种)和1个未命名藻以及不明藻类固着器,另包含有宏体后生动物,可能的后生动物以及遗迹化石.瓮会生物群不但含有鄂西庙河生物群和皖南蓝田植物群的分子,也有南澳大利亚Ediacara生物群和俄罗斯WhiteSea生物群的分子,而且具有自已的特征而有别于其他伊迪卡拉期的生物群.其宏体藻类形态变化较大,组织器官和功能已出现明显的分化,并与高等植物之间存在一定的演化关系.宏体藻类多为直立固着于海底,提高了光合作用的效率,增加了水体中的含氧量.同时,宏体藻类作为生态系统中的初级生产者成为一种新的食物,改变了后生动物的食谱.因此,陡山沱期的宏体植物不仅改善了环境,为依赖一定氧而生活、生长和繁殖的后生动物给予了必要的支持,而且作为生态系统中的必要基础,为宏体后生动物的快速发展和演化提供了一个新的食物源.另外,宏体生物群的繁盛不仅提高了有机质的生产率,而且促进了富有机碳的沉积和保存.  相似文献   

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