华南滇东地区震旦(Ediacaran)系顶部Longfengshaniaceae藻类化石的发现及意义

本文报道了在中国云南东部晋宁、江川地区的震旦(Ediacaran)系顶部渔户村组旧城段新发现的龙凤山藻科(Longfengshaniaceae)化石,与华北燕山地区新元古代青白口系长龙山组及北美中元古代小达尔群产出的Longf engshania化石明显不同,叶状体形态更为多样,呈梭形、枣核形、铲形、长条带形或球囊形等,拟茎较粗壮,与叶状体的接合很平缓,部分可见盘状、短茎状、披针状固着构造和叶状体萌生现象。依据形态记述了2属6种,包括1新属2新种3相似种,讨论和修订了龙凤山藻的科、属特征。华南滇东地区这些宏体藻类化石的发现进一步表明震旦(Ediacaran)纪末期也存在后生植物的多样化发展,可能为早寒武世“澄江生物群”的爆发性演化奠定了生态基础。     

华南埃迪卡拉(震旦)系顶部地层划分及与寒武系界线FAD分子的选择

"雪球事件"以来,早期生命呈现多层次、大规模的加速演化,到寒武纪前夕,生命大爆发达到高潮;在生命剧烈演替的同时,地球环境标志也发生着响应,碳同位素剧烈漂移,并且与各个生命演化节点相对应。但是在划分最重要的地质界线,埃迪卡拉(震旦)系——寒武系界线及界线层型和点位("金钉子",GSSP)确立的问题上迄今仍存在着较大的分歧,以遗迹化石Treptichnus pedum作为该GSSP的标志化石,因其跨系、跨阶产出,生物延限长,因而在全球的生物地层划分对比中(特别在西伯利亚和中国华南地区)一直质疑声不断,而且以遗迹化石作为标志化石本身也具有一定的缺陷。中国华南地区两类古老的宏体化石——矿化管状的Cloudina和条带状的Shaanxilithes在全球范围内可以很好的对比,并且这两种实体化石的出现都对应着碳同位素的明显正漂移。本文通过研究华南震旦系顶部化石带的地层分布和地理分布,综合分析了其时空分布特点和系统演化意义,深入探讨了Cloudina和Shaanxilithes作为寒武系底界标志化石所具备的潜力,对埃迪卡拉(震旦)纪—寒武纪地层界线划分和层型选择提出了更为理想的标准。     

华南伊迪卡拉纪宏体生物群的古地理分布及意义*

伊迪卡拉纪（635—542Ma）是前寒武纪全球大规模末次冰期（Marinoan）结束后至寒武纪“生命大爆发”之前一段重要的地质时期,由于受到新元古代气候和环境剧变的影响,真核生物乃至多细胞生物迅速演化、分异,出现显著的适应辐射。中国华南的伊迪卡拉系——震旦系陡山沱组和灯影组及其相当地层代表着这一特殊地史时段的沉积,地层记录完整,岩相环境多样,化石产出丰富,是深入研究伊迪卡拉（震旦）纪（Ediacaran/Sinian）地层划分及全球对比、探讨早期多细胞生物起源和辐射的理想地区之一。其中,扬子台地边缘相地层中出露丰富的宏体化石材料,分异显著,具有较为独特的组合面貌。近年取得的研究成果表明华南宏体化石群中也含有澳洲伊迪卡拉生物群和俄罗斯白海生物群的典型分子。作者总结了前人关于华南伊迪卡拉纪岩相古地理的研究成果;重点展示了近年来开始研究的贵州江口“翁会生物群”、云南“江川生物群”的宏体化石;简要记述了华南伊迪卡拉系中以“庙河生物群”为代表的若干宏体生物群的古地理位置及其宏体化石组合特征,据此提出了华南伊迪卡拉纪丰富多样的宏体生物群基本发育在扬子台地边缘碎屑岩至碳酸盐岩相的过渡带和斜坡带;各生物群宏体化石的组合面貌受沉积微相的制约,存在一定的变化规律。宏体化石记录表明在这一时期,伴随着显著的气候和环境变化,不仅发生了一系列重要的生物演化事件,比如：多细胞藻类和后生动物普遍开始出现多样化发展,为寒武纪生命的演化辐射奠定了生态基础;而且在华南地区已经形成了一个全新的浅海生态系统,以浮游和底栖真核藻类为主的海洋初级生产者大量繁盛,尤其是丰富的多细胞藻类可能成为前寒武纪末期至寒武纪早期主要的生烃植物类群。     

华南伊迪卡拉(震旦)系顶部建阶层型和界线层型新资料

新元古代与寒武纪之交,即伊迪卡拉纪—寒武纪过渡期,是地球历史上一个重大的地质突变期,出现了一系列地质环境变化事件和生物快速演化事件。云南东部位于扬子地区西南缘,在前寒武纪—寒武纪过渡期属于开放式浅水台地至台缘斜坡环境,是中国伊迪卡拉(震旦)系顶部与底寒武统基本连续沉积的典型地区,也曾是中国震旦系与寒武系界线层型候选剖面所在地。近年来,在此新发现了更为丰富的宏体藻类化石、遗迹化石和伊迪卡拉生物群的疑似后生动物化石等(江川生物群),以及大量以条带状Shaanxilithes为代表的宏体化石层。相关剖面自下而上从灯影组至磷矿沉积层(中谊村段)出露有连续的宏体化石记录,研究后可以细分伊迪卡拉系顶部灯影峡阶的化石带,并与底寒武统晋宁阶、梅树村阶对接,具有作为标准层型剖面的较大潜力,为伊迪卡拉纪末期年代地层单位的建阶分层、对比及确立层型剖面,以及与寒武纪最早期年代地层的界线划分提供了更为理想的标准。     

湖北峡东地区埃迪卡拉系陡山沱组微体化石的新材料

通过对牛坪剖面和新测的晓峰河剖面燧石结核和条带的切片研究,进一步证实峡东地区陡山沱组下部和上部分别含有不同的微体化石组合。下组合以大型具刺疑源类Tianzhushania为主,包括疑源类Appendisphaera magnifica、Leiosphaeridia tenuissima、Meghystrichosphaeridium chadianensis、Tanarium sp.、Tianzhushania fissura、T.spinosa、T.sp.、Unnamed A;丝状蓝藻Oscillatoriopsis longa、Polytrichoides induviatus、Salome hubeiensis、Siphonophycus kestron、S.robustum;多细胞藻类Sarcinophycus palilloformis、Unnamed multicelluar alga A。上组合以出现大量个体介于50～140μm的呈聚集保存的球状膜壳为特征,包括疑源类Leiosphaeridia tenuissima、Knollisphaeridium maximum、K.sp.、Meghystrichosphaeridium perfectum及Unnamed B、C。本文的两个微体化石组合与Yin等(2011)和Liu等(2013)的组合特征基本一致。     

建议在我国统一使用全球通用的正式年代地层单位——埃迪卡拉系（纪）

震旦系（纪）的涵义屡屡变更,争论不断,出现过许多问题。系名Sinian（震旦系）和系的“层型剖面”都是在选取“末元古系”的正式名称和“金钉子”的国际竞争中没有得到多数国际学者支持的候选名称和候选剖面。我国最新正式修订的“震旦系（纪）”与全球年代地层（地质年代）单位埃迪卡拉系（纪）的概念完全相当。系一级的全球单位一旦正式...     

Discoveries of new Longfengshaniaceae from the uppermost Ediacaran in eastern Yunnan, South China and the significance

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]     

A New Diverse Macrofossil Lagerstatte from the Uppermost Ediacaran of Southwestern China

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.     

A New Diverse Macrofossil Lagerst?tte from the Uppermost Ediacaran of Southwestern China

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.     

A New Diverse Macrofossil Lagersttte from the Uppermost Ediacaran of Southwestern China

A new macrofossil Lagersttte 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 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 hoidfast structures distinguishes this assemblage from the other Ediacaran macrofossil Lagerstttes in the Doushantuo Formation at Miaohe,Wenghni 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.     

论云南武定旧城组的地质时代

通过地层层序与生物群分析，云南武定地区旧城组的时代相当于早泥盆世Ｅｍｓｉａｎ晚期。武定地区泥盆系连续沉积，旧城组之下为具“坡脚动物群”的坡脚组，与郁江组相当。旧城组应是四排阶的沉积，产有丰富的节甲鱼类化石，面貌与欧洲及澳大利亚同期的节甲鱼类相近。海口组应归入中泥盆世早期的Ｅｉｆｅｌｉａｎ阶，大致相当于湖南的跳马涧组。     

New Benthic Fossils from the Late Ediacaran Strata of Southwestern China

The Jiangchuan Biota from the Jiucheng Member (Mb.) of the Dengying Formation (Fm.), discovered in Jiangchuan, eastern Yunnan, China, is marked by copious macrofossils at the apex of the Ediacaran strata. This fauna features benthic algae with varied holdfasts and other fossils of indeterminate taxonomic affinity and is compositionally unique compared to the Shibantan and Gaojiashan biotas of the Dengying Fm. and the Miaohe and Wenghui biotas of the Doushantuo Fm., elsewhere in China. One novel benthic saccular macroalgal fossil, named here Houjiashania yuxiensis gen. and sp. nov., from the Jiangchuan Biota is based on fossils that are sausage-shaped, elongate, tubular, ranging from 0.3 to 4 cm in length, and up to 0.8 cm in diameter. One terminus is blunt and rounded to an obtuse angle, the other is bent with a spread-out surface resembling a holdfast, suggesting a three-dimensional thallus. Thin, stipe-shaped outgrowths, likely vestiges of sessile saccular life forms, are prevalent in macroalgal fossils of analogous size and shape, as well as present brown algae Scytosiphonaceae, such as Colpomenia and Dactylosiphon. The new findings augment the diversity of benthic algae, such as those known from the Early Neoproterozoic Longfengshan Biota in North China. The benthic algal macrofossils in the Jiucheng Mb. add to knowledge of Late Ediacaran metaphyte diversification and offer more clues about the evolutionary positioning of primitive macroalgae. The co-occurrence of numerous planktonic and benthic multicellular algae and planktonic microbes might have facilitated ecologically the more extensive later Cambrian explosion evidenced by the Chengjiang Biota in Yunnan.     

Discovery of Trace Fossils from the Sinian-Cambrian Boundary Beds in Eastern Yunnan and Their Significance for Global Correlation

There are abundant and highly varied trace fossils in the Sinian-Cambrian boundary beds in eastern Yunnan. Collections from 27 sections and their study give altogether 45 ichnogenera and 87 ichnospecies. Among them, 2 ichnogenera and 7 ichnospecies are new, and 31 known ichnogenera and 38 known ichnospecies first found in the region. According to their order of appearance in the boundary beds and their assemblage features, the trace fossils in the Sinian-Cambrian boundary beds in the region may fall into 4 trace fossil assemblage zones in ascending order. In the paper they are correlated with those in the equivalent horizons abroad and their geological significance is discussed preliminarily.     

黔东北伊迪卡拉（震旦）纪陡山沱期的古地理环境

南沱冰期后的伊迪卡拉纪陡山沱期,全球海平面逐渐上升,宏体生物群（包括蓝田生物群、瓮会生物和庙河生物群等）广泛出现在扬子地区,使扬子地区陡山沱期的古地理研究成为目前研究的热点之一。在黔东北江口一铜仁地区的陡山沱组中产有丰富的宏体生物（“瓮会生物群”）和圆柱状叠层石,同时通过对遵义一铜仁陡山沱组多剖面岩性及岩性组合特征的分析和研究,认为在江口德旺地区可能存在有隆起的大陆边缘,其东侧为大陆边缘前缓斜坡相,西侧为半封闭台地相。