贵州瓮安磷矿晚前寒武纪陡山沱期的藻类化石群

LATE PRECAMBRIAN WENG'AN BIOTA FROM GUIZHOU, SOUTHWEST CHINA

贵州省瓮安地区震旦纪陡山沱期磷块岩中的化石生物群是一个属种丰富,类型众多,保存完好的晚前寒武纪生物群。它由多细胞藻类、胶鞘丝状体、球状体和疑源类组成,包括11属12种和若干未正式定名的类型,其中以多细胞藻类占优势。这一生物群的发现和研究,为探讨前寒武纪后生植物起源和发展提供了可贵的资料,同时对讨论陡山沱期磷块岩的形成环境和震旦纪的地层对比具有很重要的意义。笔者称此生物群为“瓮安生物群”。

The phosphate rocks of the Late Sinian Doushantuo Formation (approximately 650 Ma)from the Weng'an Phosphate Mines of Guizhou, Southwest China, contain an exceptionallywell-preserved fossil assemblage of thallophytes, acritarchs, coccoid and filamentouscyanobacteria. Unlike other Late Precambrian biotas, this assemblage is dominated bymacroscopic, multicellular thallophytes with well-preserved tissues and microstructures.Another notable feature of the assemblage lies in the acanthomorphic acritarchs containedtherein, together with a few coccoid and filamentous blue--green algal microfossils preservedin phosphate rocks and stromatolites. These fossils constitute a biota living in the phosphatesedimentary basin of Late Precambrian and showing an obvious ecological divergence. Heredescribed are 8 genera and 5 unnamed-types of these fossils: Thallophytes--Thallophyca ramosa, Wengania globosa; Acritarchs--Cymatiosphaeroides kullingii, Weng'an unnamed--types Cyanobacteria--Oscillatoriopsis sp., Eomycetops p., Paratetraphycus gigantous,Gloeocapsomorpha prisca, Eoentophysalis sp., Chroococcus-like types Ⅰ,Ⅱ.