Ediacaran Acanthomorphic Acritarchs and Other Microfossils from Chert Nodules of the Upper Doushantuo Formation in the Yangtze Gorges Area, South China

2014 ◽  
Vol 88 (S72) ◽  
pp. 1-139 ◽  
Author(s):  
Pengju Liu ◽  
Shuhai Xiao ◽  
Chongyu Yin ◽  
Shouming Chen ◽  
Chuanming Zhou ◽  
...  

Silicified microfossils preserved in chert nodules of the Doushantuo Formation in the Yangtze Gorges area of South China have great potential to improve the biostratigraphic subdivision and correlation of the Ediacaran System. This potential can be realized only if solid taxonomy is available. However, a systematic treatment of these microfossils (particularly acanthomorphic acritarchs) is lacking, greatly limiting their biostratigraphic potential. This paper presents the systematic paleontology of silicified microfossils from upper Doushantuo Formation (Member III) chert nodules at three sections in the Yangtze Gorges area. More than 90 species of microfossils are described, including 66 named taxa of acanthomorphs, seven named taxa of sphaeromorphs, 12 taxa of cyanobacterial filaments and coccoids, four taxa of algal thalli, and two species of tubular microfossils. Several acritarch species, includingAppendisphaera clavan. sp.,Mengeosphaera grandispinan. sp.,M. stegosauriformisn. sp.,Leiosphaeridia, and possiblySinosphaera rupina, are shown to be multicellular organisms, consistent with the proposition that some Ediacaran acritarchs may be diapause eggs of early animals. This study supports the view that theTianzhushania spinosaacanthomorph biozone is unique to the lower Doushantuo Formation in South China (and perhaps its equivalent in northern India) and that Ediacaran acanthomorph assemblages from Australia, Siberia, and East European Platform are younger than theTianzhushania spinosabiozone. It is proposed that the first occurrence ofHocosphaeridium anozos, a species with easily recognizable morphology and wide taphonomic and geographic distributions, be used to define the second Doushantuo acanthomorph biozone succeeding theTianzhushania spinosabiozone. New taxa described in this paper include three new genera (Bispinosphaeran. gen.;Yushengian. gen.; andGranitunican. gen.) and 40 new species:Appendisphaera?brevispinan. sp.,A. clavan. sp.,A.?hemisphaerican. sp.,A. longispinan. sp.,A. setosan. sp.,Bispinosphaera peregrinan. gen. n. sp.,Crinita paucispinosan. sp.,Ericiasphaera densispinan. sp.,Hocosphaeridium dilatatumn. sp.,Knollisphaeridium denticulatumn. sp.,K. longilatumn. sp.,K. obtusumn. sp.,K. parvumn. sp.,Mengeosphaera angustan. sp.,M. bellulan. sp.,M.cf.bellulan. sp.,M. constrictan. sp.,M.?cuspidatan. sp.,M.?gracilisn. sp.,M. grandispinan. sp.,M. latibasisn. sp.,M. miniman. sp.,M. spicatan. sp.,M. spinulan. sp.,M. stegosauriformisn. sp.,M. triangularisn. sp.,M. uniformisn. sp.,Sinosphaera asteriformisn. sp.,Tanarium acusn. sp.,T. elegansn. sp.,T. longitubularen. sp.,T.?minimumn. sp.,T. obesumn. sp.,T. variumn. sp.,Urasphaera fungiformisn. sp.,U. nuptan. sp.,Yushengia ramispinan. gen. n. sp.,Granitunica mcfaddeniaen. gen. n. sp.,Osculosphaera arcelliformisn. sp., andO. membraniferan. sp.

2014 ◽  
Vol 88 (1) ◽  
pp. 1-67 ◽  
Author(s):  
Shuhai Xiao ◽  
Chuanming Zhou ◽  
Pengju Liu ◽  
Dan Wang ◽  
Xunlai Yuan

The Doushantuo Formation at Weng'an in Guizhou Province, South China, is best known for animal embryo-like microfossils preserved in phosphorites. However, this unit also contains a diverse assemblage of three-dimensionally phosphatized acanthomorphic acritarchs, which are useful in the biostratigraphic subdivision and correlation of the lower–middle Ediacaran System. These acritarchs can be studied using both thin sectioning and acid maceration techniques, thus have the potential to resolve taxonomic inconsistencies between acritarchs preserved in cherts and shales. This paper presents a systematic treatment of acanthomorphs (and related spheroidal microfossils) from the Doushantuo Formation at Weng'an. More than 40 distinct species are described, including the following new species:Asterocapsoides robustusn. sp.,Knollisphaeridium?bifurcatumn. sp.,Megasphaera cymbalan. sp.,Megasphaera patellan. sp.,Megasphaera puncticulosan. sp.,Mengeosphaera eccentrican. gen. n. sp.,Papillomembrana boletiformisn. sp.,Sinosphaera variabilisn. sp.,Tanarium victorn. sp.,Tianzhushania raran. sp.,Variomargosphaeridium gracilen. sp., andWeissiella brevisn. sp. The Weng'an microfossil assemblage is dominated byMegasphaeraandMengeosphaerabut shares some taxa that are characteristic of theTianzhushania spinosabiozone and theTanarium conoideum–Hocosphaeridium scaberfacium–Hocosphaeridium anozosbiozone recognized in the Yangtze Gorges area. It may represent a transitional assemblage between these two biozones. The Weng'an microfossil assemblage also shares some elements with Ediacaran acanthomorph assemblages from Australia, Siberia, and East European Platform, indicating at least partial biostratigraphic overlap with those assemblages. Among the taxa described here,T. spinosaandH. anozosemerges as easily recognizable and widely distributed acanthomorph species whose first appearance may be used to define acanthomorph biozones for regional and global biostratigraphic correlation of lower–middle Ediacaran successions.


2017 ◽  
Vol 154 (6) ◽  
pp. 1193-1201 ◽  
Author(s):  
CHUANMING ZHOU ◽  
XIAN-HUA LI ◽  
SHUHAI XIAO ◽  
ZHONGWU LAN ◽  
QING OUYANG ◽  
...  

AbstractAs a well-known phosphatized Lagerstätte, the Ediacaran Weng'an biota in central Guizhou Province of South China contains diverse acanthomorphic acritarchs, algal thalli, tubular microfossils as well as various spheroidal fossils. These fossils provide crucial palaeontological evidence for the radiation of multicellular eukaryotes after the termination of the Neoproterozoic global glaciation. While the Weng'an biota is generally considered as early Ediacaran in age on the basis of phosphorite Pb–Pb isochron ages ranging from 572 Ma to 599 Ma, the reliability and accuracy of these age data have been questioned and some geologists have proposed that the Weng'an biota may be younger than 580 Ma instead. Here we report a SIMS zircon U–Pb age of 609 ± 5 Ma for a tuffaceous bed immediately above the upper phosphorite unit in the Doushantuo Formation at Zhangcunping, Yichang, South China. Litho-, bio- and chemostratigraphic correlations suggest that the upper phosphorite unit at Zhangcunping can be well correlated with the upper phosphorite unit at Weng'an, which is the main horizon of the Weng'an biota. We therefore conclude that the Weng'an biota could be as old as 609 ± 5 Ma.


2010 ◽  
Vol 80 (5) ◽  
pp. 670-683 ◽  
Author(s):  
GUO Qingjun ◽  
LIU Congqiang ◽  
Harald STRAUSS ◽  
Tatiana GOLDBERG ◽  
ZHU Maoyan ◽  
...  

2021 ◽  
Author(s):  
Sheng‐Lan Xu ◽  
Tatiana M. Kodrul ◽  
Natalia P. Maslova ◽  
Han‐Zhang Song ◽  
Anna V. Tobias ◽  
...  
Keyword(s):  

Author(s):  
Qiong Chen ◽  
Guochun Zhao ◽  
Min Sun

Neoproterozoic to Paleozoic sedimentation shows systematic temporal-spatial variations within South China, which must be considered in reconstructing geological evolution of South China in response to global plate reorganization from the breakup of Rodinia to the assembly of Gondwana. We use >1000 new U-Pb and Hf isotopic data for detrital zircons from Neoproterozoic−Cambrian strata across the western (i.e., Longmenshan) and eastern (i.e., Wuyishan) margins of South China, coupled with compiled stratigraphic and magmatic information, to constrain change in provenance through time. First-order conclusions are as follows: (1) detrital zircons from the Neoproterozoic strata of the two margins were mainly sourced from the Panxi-Hannan arc and the Jiangnan orogen, signaling a rough self-sufficient sedimentary system; (2) newly identified Cambrian molasse-like sediments in the western margin, in which abundant detrital zircons are 550−500 Ma old with positive εHf(t) values, were mainly derived from the 580−500 Ma Cadomian arc belt along the Iran-Turkey margin; and (3) the Cambrian sediments in the eastern margin document more increased contributions from the Grenvillian-age provinces most possibly in Australia. Such spatial-temporal provenance variations signal the northward drifting of South China, from a position connecting with Iran-Turkey and northern India to that approaching Australia during the late Neoproterozoic−Cambrian period. We highlight that the activity of oblique oceanic-continental convergence accreted Asian terranes onto the northern margin of Gondwana, hence contributing to the ultimate Gondwana architecture under global plate reorganization.


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