苏皖北部新元古代宏体碳质化石(英文)  

NEOPROTEROZOIC MILLIMETRIC-CENTIMETRIC CARBONACEOUS FOSSILS FROM NORTHERN ANHUI AND JIANGSU,CHINA

作　　者：钱迈平[1] 姜杨[1] 余明刚[1] 

机构地区：[1]南京地质矿产研究所,南京210016

出　　处：《古生物学报》2009年第1期73-88,共16页Acta Palaeontologica Sinica

基　　金：国家自然科学基金(No.40872006);科技部重大基础研究项目(G2000077700);科技部科技基础工作专项(2001DEB20056);中国地质调查局基础地质综合研究项目(1212010610611)联合资助

摘　　要：相对于需用显微镜才能看到的微体化石而言,宏体碳质化石是肉眼可见、个体大小达毫米-厘米级、具一定几何形状、在地层中呈压扁状保存的独特生物碳化遗留物。它们在世界各地的元古代海相泥岩或页岩地层中分布较广,地质年代范围从古元古代到寒武纪,尤其在新元古代更显优势。宏体碳质化石通常呈微米级厚,大小范围从略小于1到大于100mm2的片状黑-褐色薄膜。它们形态各异,变化范围从光滑、起皱、扭曲或具环纹的圆形、椭圆形、香肠形到不规则的角形等个体。大多无清晰稳定的表面装饰或内部构造,难以进一步分类。在许多标本中,原生的压实作用引起的折皱方式在某种程度上说明其是具有柔软的外壁包裹着活性流体物质的海洋生物。苏皖北部新元古界富产宏体碳质化石,它们主要分布于安徽寿州、凤阳、宿州、灵璧,江苏铜山及山东苍山等地,均保存于细腻的粘土含量较高的页岩或泥岩中,化石保存完好程度与岩性的细腻程度成正比。分布较广且数量较多的是Chuaria,其次为Tawuia,而表面具细密横纹的宏体碳质化石仅见于淮南少数地点的刘老碑组、九里桥组,以及淮北少数地点的史家组、金山寨组和沟后组。它们曾被分类命名多达52个形态属种。然而,后来的研究发现,其中大多是同物异名、不符合国际命名规范及分类地位有问题者(Sun and Zhou,1986;Hofmann,1994;钱迈平等,2000,2008;Dongetal.,2008)。经清理甄别归纳后,也许只有4个形态属种有效。它们分别是:1)Chuaria circularis Walcott,1899,圆—短椭圆形及因埋藏状况呈现的各种变形,长宽比<2。表面无稳定装饰,呈光滑或常在边缘及其附近有环向或斜切向皱纹;2)Tawuia dalensis Hofmann et Aitken,1979,长椭圆-香肠形及因埋藏状况呈现的各种变形,长宽比≥2。表面无稳定装饰,呈光滑或不定向皱纹;3)Tyrasotaenia podolica GnilovskayaMillimetric-centimetric carbonaceous compressions are exceptionally preserved on bedding planes in dark grey argillaceous shales of the Neoproterozoic, North China. Four morphological taxa are recognized. Most specimens are assigned to Chuaria-Tawuia types. Some specimens show both a holdfast and a vegetative thallus, indicating they were benthic muhicellular algae. Each form is characterized by a certain morphological appearance, e.g. spheroidal-Chuaria circularis , tomaculate- Tawuia delensis , taenioidal- Tyrasotaenia podolica , annulated, and tomaeulate, which had been described as metazoan, Sinosabellidites huainanensis. Two to three different forms and more than 10 individuals are well preserved on the same bed within an area less than 100cm^2. The assemblage consis- ting mostly of macroscopic remains, Chuaria and Tawuia, are common in Neoproterozoic paleobiotas. Similar ones have been reported from the Little Dal Group of the Mackenzie Mountain and Shaler Supergroup of the Victoria Island, Canada. But the lack of distinctive ornamentation or internal structure makes it difficult for further classification. Sinosabellidites, known only from the Neoproterozoic sedimentary sequence in northern Anhui and Jiangsu provinces, China, is morphologically similar to some modern chlorophytes.

关 键 词：藻类 新元古代 苏皖北部 中国 

分 类 号：Q911[天文地球—古生物学与地层学]