Yangtziramulus zhanginew genus and species, a carbonate-hosted macrofossil from the Ediacaran Dengying Formation in the Yangtze Gorges area, South China

2009 ◽  
Vol 83 (4) ◽  
pp. 575-587 ◽  
Author(s):  
Bing Shen ◽  
Shuhai Xiao ◽  
Chuanming Zhou ◽  
Xunlai Yuan
Keyword(s):  
South China ◽  
Life Forms ◽  
Black Shales ◽  
Benthic Organism ◽  
New Genus And Species ◽  
Additional Material ◽  
Fine Grained ◽  
Dengying Formation ◽  
Ecological Complexity ◽  
Siliciclastic Rocks

Very few macroscopic soft-bodied Ediacaran fossils are hosted in carbonates; most of them are preserved as casts and molds in siliciclastic rocks or as carbonaceous compressions in black shales. This taphonomic bias limits our capability to fully understand the diversity and paleoecology of macroscopic Ediacaran life forms. Previous reports have shown that the upper Ediacaran Dengying Formation in South China and Khatyspyt Formation in Siberia contain macroscopic soft-bodied fossils preserved in bituminous limestone; thus they have the potential to expand our knowledge about the Ediacaran biosphere. However, the biogenecity of the Dengying fossils described in Xiao et al. (2005) has been questioned. In this paper, we provide additional material and arguments in support of the biogenecity of these fossils, which are formally described asYangtziramulus zhanginew genus and species.Yangtziramulus zhangiconsists of a branching system with a central axis and tubes on both sides. The tubes appear to be distally open.Yangtziramulus zhangiis interpreted as a flat-lying benthic organism, as indicated by the mutual avoidance relationship among densely clustered individuals.Yangtziramulus zhangifinds few morphological analogs among modern organisms, but it is broadly similar to several macroscopic Ediacaran forms. Its morphological and ecological complexity is inconsistent with a microbial interpretation.Yangtziramulus zhangiis typically covered by a thin veneer of fine-grained silts, suggesting that it was probably smothered and killed by an episodic flux of silty sediments (event deposits). Its tube walls are replaced with early diagenetic calcspars.

A new modular palaeopascichnid fossil Curviacus ediacaranus new genus and species from the Ediacaran Dengying Formation in the Yangtze Gorges area of South China

2017 ◽  
Vol 154 (6) ◽  
pp. 1257-1268 ◽  
Author(s):  
BING SHEN ◽  
SHUHAI XIAO ◽  
CHUANMING ZHOU ◽  
LIN DONG ◽  
JIEQIONG CHANG ◽  
...  
Keyword(s):  
South China ◽  
New Genus ◽  
Three Dimensional ◽  
Internal Anatomy ◽  
Carbonate Facies ◽  
New Genus And Species ◽  
Modular Organisms ◽  
Dengying Formation ◽  
Body Construction ◽  
Phylogenetic Affinities

AbstractNon-biomineralizing Ediacaran macrofossils are rare in carbonate facies, but they offer valuable information about their three-dimensional internal anatomy and can broaden our view about their taphonomy and palaeoecology. In this study, we report a new Ediacaran fossil, Curviacus ediacaranus new genus and species, from bituminous limestone of the Shibantan Member of the Dengying Formation in the Yangtze Gorges area of South China. Curviacus is reconstructed as a benthic modular organism consisting of serially arranged and crescent-shaped chambers. The chambers are confined by chamber walls that are replicated by calcispars, and are filled by micritic sediments. Such modular body construction is broadly similar to the co-occurring Yangtziramulus zhangii and other Ediacaran modular fossils, such as Palaeopascichnus. The preservation style of Curviacus is similar to Yangtziramulus, although the phylogenetic affinities of both genera remain unresolved. The new fossil adds to the diversity of Ediacaran modular organisms.

Silicified tubular microfossils from the Upper Doushantuo Formation (Ediacaran) in the Yangtze Gorges area, South China

2009 ◽  
Vol 83 (4) ◽  
pp. 630-633 ◽  
Author(s):  
Pengju Liu ◽  
Shuhai Xiao ◽  
Chongyu Yin ◽  
Feng Tang ◽  
Linzhi Gao
Keyword(s):  
South China ◽  
New Genus ◽  
Black Shales ◽  
New Genus And Species ◽  
Doushantuo Formation ◽  
Environmental Distribution

The ediacaran Doushantuo Formation in the Yangtze Gorges area (Fig. 1.2) contains abundant silicified cyanobacterial coccoids and filaments (Y. Zhang et al., 1998), acanthomorphic acritarchs (Zhou et al., 2007), multicellular algae (Xiao, 2004), and possible animal embryos (L. Yin et al., 2007). These silicified fossils are taxonomically similar to the phosphatized fossils in the Doushantuo Formation of the Weng'an area, South China (Y. Zhang et al., 1998). However, the Weng'an assemblage contains tubular microfossils that have not been previously documented in the Yangtze Gorges area. Here we report the occurrence of secondarily silicified tubular microfossils—Sinocyclocyclicus guizhouensis(Xue et al., 1992) andYangtzitubus semiteresnew genus and species—from lenticular cherts in the upper Doushantuo Formation in the Yangtze Gorges area. Of the two named taxa,Sinocyclocyclicus guizhouensiswas previously known from the Weng'an area (Liu et al., 2008). The new data extend the geographic, taphonomic, and environmental distribution of Doushantuo tubular microfossils. A fuller documentation of the Doushantuo biodiversity is also important to the evaluation of possible taphonomic or environmental biases among the three exceptional taphonomic windows—carbonaceous compression (Xiao et al., 2002), phosphatization (Xiao and Knoll, 1999), and silicification (Y. Zhang et al., 1998)—in Doushantuo black shales, phosphorites, and cherts, respectively.

scholarly journals New phiocricetomyine rodents (Hystricognathi) from the Jebel Qatrani Formation, Fayum Depression, Egypt

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12074
Author(s):  
Shorouq F. Al-Ashqar ◽  
Erik R. Seiffert ◽  
Dorien de Vries ◽  
Sanaa El-Sayed ◽  
Mohamed S. Antar ◽  
...  
Keyword(s):  
New World ◽  
New Genus ◽  
Late Eocene ◽  
Type Locality ◽  
New Genus And Species ◽  
Additional Material ◽  
Early Oligocene ◽  
Species Type ◽  
The Rich ◽  
Latest Eocene

Background The rich rodent assemblages from the Eocene–Oligocene deposits of the Jebel Qatrani Formation (Fayum Depression, Egypt) have important implications for our understanding of the origin and paleobiogeography of Hystricognathi, a diverse clade that is now represented by the Afro-Asiatic Hystricidae, New World Caviomorpha, and African Phiomorpha. Methods Here we present previously undescribed material of the enigmatic hystricognath clade Phiocricetomyinae, from two stratigraphic levels in the lower sequence of the Jebel Qatrani Formation—a new genus and species (Qatranimys safroutus) from the latest Eocene Locality 41 (~34 Ma, the oldest and most productive quarry in the formation) and additional material of Talahphiomys lavocati from that species’ type locality, early Oligocene Quarry E (~31–33.2 Ma). Results The multiple specimens of Qatranimys safroutus from L-41 document almost the entire lower and upper dentition, as well as mandibular fragments and the first cranial remains known for a derived phiocricetomyine. Specimens from Quarry E allow us to expand comparisons with specimens from Libya (late Eocene of Dur at-Talah and early Oligocene of Zallah Oasis) that have been placed in T. lavocati, and we show that the Dur at-Talah and Zallah specimens do not pertain to this species. These observations leave the Fayum Quarry E as the only locality where T. lavocati occurs.

scholarly journals Origin and Enrichment of Vanadium in the Lower Cambrian Black Shales, South China

ACS Omega ◽  
2021 ◽  
Author(s):  
Tong Wu ◽  
Ruidong Yang ◽  
Lei Gao ◽  
Jun Li ◽  
Junbo Gao
Keyword(s):  
South China ◽  
Lower Cambrian ◽  
Black Shales

scholarly journals A new type of slumping-induced soft-sediment deformation structure: the envelope structure

Geologos ◽  
2019 ◽  
Vol 25 (2) ◽  
pp. 111-124
Author(s):  
Uk Hwan Byun ◽  
A.J. Tom van Loon ◽  
Yi Kyun Kwon ◽  
Kyoungtae Ko
Keyword(s):  
Slope Failure ◽  
Gravity Flow ◽  
Soft Sediment ◽  
Deformation Structure ◽  
Rare Type ◽  
Fine Grained ◽  
Sediment Deformation ◽  
Soft Sediment Deformation ◽  
The Difference ◽  
Siliciclastic Rocks

Abstract The sediments of the Cretaceous Gyeokpori Formation in south-western South Korea accumulated in a lake in which mainly siliciclastic rocks were deposited, with some interbedded volcaniclastics. The nearby volcanic activity resulted in unstable lake margins inducing a dominance of gravity-flow deposits. The high sedimentation rate facilitated soft-sediment deformation on the sloping margin. The deposition of numerous gravity-flow deposits resulted in a vertically heterolithic stratification. The slumps are composed of different lithologies, which is expressed in different types of deformation due to the difference in cohesion between sandy and mussy layers within the slumps. Coarser-grained (cohesionless) slumps tend to show more chaotic deformation of their lamination or layering. The difference in slumping behaviour of the cohesive and non-cohesive examples is explained and modelled. A unique soft-sediment deformation structure is recognized. This structure has not been described before, and we call it ‘envelope structure’. It consists of a conglomerate mass that has become entirely embedded in fine-grained sediment because slope failure took place and the fine-grained material slumped down with the conglomerate ‘at its back’. The cohesive laminated mudstone formed locally slump folds that embedded the non-cohesive overlying conglomerate unit, possibly partly due to the bulldozing effect of the latter. This structure presumably can develop when the density contrast with the underlying and overlying deposits is exceptionally high. The envelope structure should be regarded as a special – and rare – type of a slumping-induced deformation structure.

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