Dengying Formation

Geologic formation in China From Wikipedia, the free encyclopedia

The Dengying Formation is an upper Ediacaran (551-541 Ma[2]) fossiliferous geologic formation found in South China. It was deposited on a shallow marine carbonate platform.[3] It also contains a rare example of Burgess Shale-type Preservation within the Ediacaran, in the form of the Tongshan Lagerstätte.[4]

TypeFormation
Sub-unitsSee: Members
UnderliesYanjiahe Formation[1]
OverliesDoushantuo Formation
Quick facts Type, Sub-units ...
Dengying Formation
Stratigraphic range: Ediacaran
~551–541 Ma
Transition between uppermost Doushantuo Formation and lowermost Dengying Formation
TypeFormation
Sub-unitsSee: Members
UnderliesYanjiahe Formation[1]
OverliesDoushantuo Formation
Lithology
PrimaryDolomite
OtherChert, Limestone
Location
RegionYangtze Gorges
CountryChina
Close

Members

Listed by ascending age:

  • The Hamajing Member is characterized by light grey, medium- to thick-bedded dolomite, intercalated with thin layers of chert.[3]
  • The Shibantan Member is interpreted to represent a subtidal environment and is composed of dark grey, thin-bedded bituminous limestone. It is the most fossiliferous of the Dengying Formation members and has yielded several trace fossils, such as Lamonte,[5] as well as possible lobopodian trackways.[6]
  • The Baimatuo Member consists of light grey, thick-bedded dolomite.[3]

Traditionally, the Tianzhushan Member was considered to be the uppermost unit of the Dengying Formation. However, its small shelly fossils and Micrhystridium-like acritarchs are a shared characteristic with the Cambrian Yanjiahe Formation.[3] The Kuanchuanpu Formation also is occasionally placed as a member of the Dengying Formation,[7] however it is likely separate for the same reasons.

Paleobiota

The Dengying formation is unique from other Ediacaran formations in that its top is almost right up against the Ediacaran - Cambrian boundary, with more recent organisms being described that have striking similarities with Cambrian fauna, like Alienum. There are also a lot of ichnogenera in the form of burrows, something that is common in younger Ediacaran rocks the closer to the Cambrian boundary they are.

A recent paper has also found a rare example of Burgess Shale-type Preservation outside of the known range of all members, in what is known as the Tongshan Lagerstätte. This preserves a wide range of fossil forms, including the first rangeomorph fronds with Burgess Shale-type preservation.[4]

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
 Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Proarticulata

More information Genus, Species ...
Genus Species Notes Images
Dickinsonia[8]
  • Dickinsonia sp.
 Oval to elongated motile organism. Only one incomplete specimen is known.
Close

Petalonamae

More information Genus, Species ...
Genus Species Notes Images
Charniodiscus[9]
  • Charniodiscus sp.
 Frondose organism.
Paracharnia[10]
  • P. denyingensis
 Frondose organism.
Pteridinium[9]
  • Pteridinium sp.
 Frondose organism.
Rangea[9]
  • Rangea sp.
 Frondose organism.
Close

Trilobozoa

More information Genus, Species ...
Genus Species Notes Images
Lobodiscus[11]
  • L. tribrachialis
 Tri-radial organism.
Close

Porifera

More information Genus, Species ...
Genus Species Notes Images
Helicolocellus[12]
  • H. cantori
 Conical sponge, possible relations to hexactinelliid sponges.
Close

incertae sedis

More information Genus, Species ...
Genus Species Notes Images
Alienum[13]
  • A. velamenus
 Vetulicolian-like organism.
Cloudina[14]
  • Cloudina sp.
 Tubular organism.
Curviacus[15]
  • C. ediacaranus
 Palaeopascichnid organism.
Conotubus[16]
  • C. hemiannulatus
 Tubular organism.
Cycliomedusa[17]
  • C. jiangchuanensis
 Discoid organism.
Eoandromeda[4]
  • E. octobrachiata
 Discoid organism.
Gaojiashania[18]
  • G. cyclus
 Tubular organism.
Hiemalora[9]
  • Hiemalora sp.
 Discoid organism, possibly holdfasts of petalonamids.
Palaeorhopalon[14]
  • P. spiniferum
 Tubular organism.
Palaeopascichnus[4]
  • P. linearis
 Palaeopascichnid organism.
Protoconites[4]
  • P. minor
 Curved conical organism, possible relations to Cnidaria.
Shufangtubulus[14]
  • S. inornatus
 Tubular organism.
Sinotubulites[19][14]
  • Sinotubulites sp.
  • S. baimatuoensis
  • S. hexagonus
  • S. pentacarinalis
  • S. triangularis
 Tubular organism.
Wutubus[9]
  • W. annularis
 Tubular organism.
Yangtziramulus[20]
  • Y. zhangi
 Enigmatic organism, affinities with other forms is unknown, although possibly related to the Petalonamae, like Charnia.
Yilingia[21]
  • Y. spiciformis
 Bilterian animal of unknown affinities, with possible relations to Panarthopoda or Annelida.
Close

Flora

More information Genus, Species ...
Genus Species Notes Images
Longfengshania[17]
  • Longfengshania sp.
 Thallus-like macroalgae.
Protocodium[22]
  • P. sinense
 Codiacean alga.
Baculiphyca[4]
  • B. taeniata
 Thallus-like macroalgae.
Zhongbaodaophyton[4]
  • Z. robustus
 Branching macroalgae.
Doushantuophyton[4]
  • D. lineare
 Branching macroalgae.
Chuaria[4]
  • Chuaria sp.
 Enigmatic fossil, possibly synonymous with Tawuia.
Beltanelliformis[4]
  • B. brunsae
 Cyanobacterial colony.
Longifuniculum[4]
  • L. dissolutum
 Whip-like macroalgae.
Close

Microorganisms

More information Genus, Species ...
Genus Species Locality Notes Images
Protolagena[23]
  • P. limbata
  • P. gaojiashanensis
  • P. papillatus
 Lower Shibantan Member (Gaojiashan and Lijiagou Sections) Vase-like microorganisms.
Sicylagena[23]
  • S. formosa
  • S. latistoma
 Lower Shibantan Member (Gaojiashan and Lijiagou Sections) Vase-like microorganisms.
Close

Ichnogenera

More information Genus, Species ...
Genus Species Locality Notes Images
Lamonte[24]
  • L. trevallis
 Middle Shibantan Member (South Quarry) Burrows.
Helminthoidichnites
  • Helminthoidichnites isp.
 Burrows.
Shaanxilithes
  • Shaanxilithes isp.
 Junior synonym of Nenoxites.
Nenoxites
  • Nenoxites isp.
 Movement traces.
Torrowangea
  • Torrowangea isp.
 Burrows.
Close

Undescribed

More information Genus, Species ...
Genus Species Locality Notes Images
ESEN 0013[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Tubular organism, possible affinities to Metazoa.
Undescribed rangeomorph "ESEN 0016"[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Frondose organism, 3 distinct lobe-like regions, consisting of a thick stalk and two petaloids, which are made up of tightly packed branches.
Fan-shaped rangeomorphs[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Two frondose organisms with a similar appearance to Bradgatia, with one of the specimens, ESEN 0018, preserving with a possible holdfast.
Undescribed rangeomorph "ESEN 0019"[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Frondose organism, with a similar appearance to Charniodiscus, consisting of a thick stalk and two petaloids, which are made up of tightly packed branches, also preserves a notable holdfast.
Undescribed rangeomorph "ESEN 0020"[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Elongated frondose organism, with a similar appearance to Paracharnia, consisting of a thin stalk and two petaloids, which are made up of tightly packed branches, alongside a possible holdfast at its base.
Zhenba columns[25]
  • ???
 Tongan Lagerstätte (Wanjia section) Possible affinities with coralline algae.
Baseball bat-shaped form[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Baseball bat-shaped form, possibly macroalgae.
Irregular circular form[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Oblong-shaped form, possibly macroalgae.
Net-like form[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Netted form, possibly macroalgae.
ribbon-like form[4]
  • ???
 Tongan Lagerstätte (Wanjia section) Ribbon like form, possibly macroalgae.
Bilateria indet.
  • Unapplicable
 Tongan Lagerstätte (Wanjia section) Known to have several pairs of appendages, but its exact affinity is unknown[26]
Close

See also

References

Related Articles

Wikiwand AI