Yanjiahe Formation

Yanjiahe Formation
Stratigraphic range: Ediacaran - Fortunian
~[1]
View of Yanjiahe River in Macheng, Huanggang, Hubei, the locality after which the formation is named.
TypeFormation
Sub-unitsSee: Beds
OverliesDengying Formation
Lithology
PrimaryShale, limestone, dolomite
OtherChert, phosphorite
Location
Coordinates30°48′N 111°18′E / 30.8°N 111.3°E / 30.8; 111.3
Approximate paleocoordinates27°36′N 160°12′E / 27.6°N 160.2°E / 27.6; 160.2
RegionHubei
CountryChina
ExtentYangtze Gorges
Type section
Named forYanjiahe River
Yanjiahe Formation (China)
Yanjiahe Formation (Hubei)

The Yanjiahe Formation is an Ediacaran to Cambrian fossiliferous geologic formation found in South China.[2][3]

Dating

The Yanjiahe Formation has been dated through various methods. The top of the formation is dated at 526.5±1.1 Ma and 526.4±5.3 Ma using radiometric dating on ash beds within the area. Likewise, the base of the formation has been dated to between 542±0 Ma to 526±0 Ma through carbon isotopic correlations.[1]

Beds

The Yanjiahe Formation consists of five beds. Every bed within the formation contains fossil material.[4]

The beds are as follows, listed by ascending age:

  • Bed 1 is characterized by basal dolomitic conglomerates, with banded black cherts.[4]
  • Bed 2 is mostly consists of siliceous phosphatic dolostone, with flat pebble conglomerates.[4]
  • Bed 3 is characterized by various shales, with the presence of siliceous-phosphatic nodules.[4]
  • Bed 4 is composed of carbonaceous limestones.[4]
  • Bed 5 is characterized by cherts and siliceous phosphatic dolostone, with flat pebble conglomerates.[4]

Paleobiota

The Yanjiahe Formation contains a wide range of unique organisms from the base of the Cambrian, from Yanjiahella to Beretella, alongside a lot of early molluscs, like Watsonella.[3]

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.

Cnidaria

Genus Species Notes Images
Octapyrgites[5]
  • O. elongatus
 Olivooid Medusozoan, larger than any known Olivooid.
Quadrapyrgites[6][7]
  • O. quadratacris
 Olivooid Medusozoan.
Olivooides[6][7]
  • Olivooides sp.
  • O. multisulcatus
  • O. mirabilis
 Olivooid Medusozoan.
Pseudooides[6][7]
  • Pseudooides sp.
 Medusozoan.
Septuconularia[8][9]
  • S. yanjiaheensis
  • S. crassiformis
 Hexangulaconulariid Medusozoan.
Decimoconularia[10]
  • D. isofacialis
 Hexangulaconulariid Medusozoan.
Carinachites[6][7]
  • C. spinatus
 Cnidarian sclerite, related to the conulariids.
Cambrorhytium[11]
  • C. major
 Elongated cone-like cnidarian.

Chancelloriida

Genus Species Notes Images
Chancelloria[7]
  • Chancelloria sp.
 Sponge-like eumetazoan.

Deuterostome

Genus Species Notes Images
Protohertzina[12][7]
  • P. unguliformis
  • P. anabarica
  • P. robusta
 Possibly a Protoconodont, Paraconodont, or a Chaetognath.
Tarimspira[6]
  • T. plana
 Possible Paraconodont.
Yunnanodus[12][1]
  • Yunnanodus sp.
  • Y. yanjiahensis
 Possible Paraconodont.
Yanjiahella[13]
  • Y. biscarpa
 Possibly earliest stem group echinoderm.
Yuknessia[14]
  • Yuknessia sp.
 Unbranched pterobranch.
Hertzina[12]
  • H. guizhouensis
  • H. tenuis
 Furnishinid Paraconodont.

Ecdysozoa

Genus Species Notes Images
Beretella[15]
  • B. spinosa
 Possibly adult or larval ecdysozoan.
Saccorhytus[6][7]
  • Saccorhytus sp.
 Possibly adult or larval ecdysozoan.

Lophotrochozoa

Genus Species Notes Images
Conotheca[14][12]
  • C. subcurvata
  • C. obesa
  • C. nana
  • C. transulcata
 Hyolith lophotrochozoan.
Hyolithellus[12]
  • H. tenuis?
  • H. decorus
 Annelid lophotrochozoan, previously thought to be a Hyolith.
Lapworthella[14]
  • Lapworthella sp.
 Tommotid lophotrochozoan.
Spinulitheca[12]
  • S. billingsi
 Hyolith lophotrochozoan.
Microcornus[12]
  • M. parvulus?
 Hyolith lophotrochozoan.
Cupitheca[12]
  • C. mira
 Hyolith lophotrochozoan.
Turcutheca[12]
  • T. crasseocochlia
  • T. lubrica
 Hyolith lophotrochozoan.
Lophotheca[12]
  • L. costellata
 Hyolith lophotrochozoan.
Circotheca[12][1]
  • C. longiconica
  • C. longiconica
 Circothecid Hyolith.
Aldanella[14][12]
  • A. attleborensis
  • A. yanjiaheensis
 Mollusc with a coiled shell.
Eohalobia[16][6][1]
  • E. diadongensis
  • Eohalobia sp.
 Halkieriid mollusc.
Ocruranus[6][16][7][1]
  • Ocruranus sp.
  • O. trulliformis
  • O. finial
 Halkieriid mollusc.
Scenella[12]
  • S. jijiapoensis
 Scenellid mollusc.
Siphogonuchites[12]
  • S. triangularis
 Siphogonuchitid mollusc.
Xianfengella[12]
  • X. ovata
  • X. prima
 Mollusc.
Tuberoconus[6][1]
  • T. paucipapillae
 Mollusc.
Watsonella[17]
  • W. crosbyi
 Mollusc.
Anabarella[17]
  • A. plana
 Helcionelloid mollusc.
Igorella[12][17]
  • I. emeiensis
  • I. maidipingensis
  • Igorella sp.
 Helcionelloid mollusc.
Oelandiella[12][1]
  • O. korobkovi
 Helcionelloid mollusc.
Ceratoconus[6][1]
  • C. bucers
 Helcionelloid mollusc.

Porifera

Genus Species Notes Images
Blastulospongia[18]
  • Blastulospongia sp.
 Globular demosponge, previously postured to be a radiolarian.
Hexactinellid spicules[4]
  • ???
 A collection of monaxons, diaxons and triaxons.

incertae sedis

Genus Species Notes Images
Anabarites[2][12][7]
  • A. trisulcatus
  • A. tianzhushanensis
  • A. gracilis
  • A. ternarius
 Anabaritid small shelly fossil.
Tiksitheca[12]
  • T. korobovi
 Anabaritid small shelly fossil.
Cambrotubulus[6][7]
  • C. decurvatus
 Anabaritid small shelly fossil.
Protoconites[14]
  • P. minor
 Curved conical organism, possible relations to Cnidaria.
Purella[14][12]
  • P. antiqua
  • P. lepidites
 Small shelly fossil.
Emeiconus[14]
  • E. antiqua
 Small shelly fossil.
Rugatotheca[7]
  • Rugatotheca sp.
 Small shelly fossil.
Coleolella[6]
  • C. recta
 Small shelly fossil.
Vendotaenid[14]
  • Vendotaenia sp.
 Ribbon-like organism.
Torellella[1]
  • T. lentiformis
 Tubicolous fossil.

Flora

Genus Species Notes Images
Archaeophycus[2][19][7]
  • A. yunnanensis
 Either a cyanobacteria or the early developmental stage of an alga. (J)
Konglingiphyton[14]
  • Konglingiphyton sp.
 Macroalgae.
Megathrix[2][20][19]
  • M. longus
 Filamentous cyanobacterium.
Myxococcoides[19]
  • Myxococcoides spp.
 Cyanobacteria.
Archaeooides[7]
  • A. granulates
 Microalgae.

Microorganisms

Genus Species Notes Images
Asteridium[20]
  • A. tornatum
 Acritarch.
Comasphaeridium[2][20]
  • C. annulare
 Acritarch.
Heliosphaeridium[2][20]
  • H. ampliatum
 Acritarch.
Micrhystridium[14]
  • M. regulare
 Acritarch.
Yurtusia[19]
  • Y. uniformis
 Acritarch.
Dictyotidium[19]
  • Dictyotidium sp.?
 Acritarch.

Undescribed

Genus Species Notes Images
Unnamed probable cnidarian[11]
  • ???
 Curved tubular organism, possible affinities to cnidarians.


See also


References

  1. ^ a b c d e f g h i j Liu, Zhanhong; Algeo, Thomas J. (June 2025). "Appearance of SSFs in earliest Cambrian seas of South China linked to salinity conditions". Chemical Geology. 683 122761. doi:10.1016/j.chemgeo.2025.122761.
  2. ^ a b c d e f Dong, Lin; Xiao, Shuhai; Shen, Bing; Zhou, Chuanming; Guoxiang, Li; Yao, Jinxian (2009), "Basal Cambrian Microfossils from the Yangtze Gorges Area (South China) and the Aksu Area (Tarim Block, Northwestern China)", Chemical Geology, 83 (1): 30–34, Bibcode:2009JPal...83...30D, doi:10.1666/07-147R.1, retrieved 2014-08-15
  3. ^ a b Yanjiahe Formation at Fossilworks.org
  4. ^ a b c d e f g Chang, Shan; Feng, Qinglai; Clausen, Sébastien; Zhang, Lei (May 2017). "Sponge spicules from the lower Cambrian in the Yanjiahe Formation, South China: The earliest biomineralizing sponge record". Palaeogeography, Palaeoclimatology, Palaeoecology. 474: 36–44. Bibcode:2017PPP...474...36C. doi:10.1016/j.palaeo.2016.06.032.
  5. ^ Guo, Junfeng; Han, Jian; Van Iten, Heyo; Song, Zuchen; Qiang, Yaqin; Wang, Wenzhe; Zhang, Zhifei; Li, Guoxiang; Sun, Yifei; Sun, Jie (May 2020). "A new tetraradial olivooid (Medusozoa) from the lower Cambrian (Stage 2) Yanjiahe Formation, South China". Journal of Paleontology. 94 (3): 457–466. Bibcode:2020JPal...94..457G. doi:10.1017/jpa.2019.101.
  6. ^ a b c d e f g h i j k l Steiner, Michael; Yang, Ben; Hohl, Simon; Zhang, Lei; Chang, Shan (September 2020). "Cambrian small skeletal fossil and carbon isotope records of the southern Huangling Anticline, Hubei (China) and implications for chemostratigraphy of the Yangtze Platform". Palaeogeography, Palaeoclimatology, Palaeoecology. 554 109817. Bibcode:2020PPP...55409817S. doi:10.1016/j.palaeo.2020.109817.
  7. ^ a b c d e f g h i j k l m Yang, Lei; Yang, Ben; Shang, Xiaodong; Steiner, Michael (June 2025). "Palaeogeographic and stratigraphic significances of Fortunian small skeletal fossils from the southern Shennongjia Region (China)". Palaeogeography, Palaeoclimatology, Palaeoecology. 668 112910. Bibcode:2025PPP...66812910Y. doi:10.1016/j.palaeo.2025.112910.
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  9. ^ Song, Zuchen; Guo, Junfeng; Han, Jian; Van Iten, Heyo; Qiang, Yaqin; Peng, Jiaxin; Sun, Jie; Zhang, Zhifei (June 2022). "A New Species of Septuconularia (Hexangulaconulariidae, Cnidaria) from Cambrian Stage 2, South China". Acta Geologica Sinica - English Edition. 96 (3): 757–765. Bibcode:2022AcGlS..96..757S. doi:10.1111/1755-6724.14917.
  10. ^ Guo, Junfeng; Han, Jian; Van Iten, Heyo; Song, Zuchen; Qiang, Yaqin; Wang, Wenzhe; Zhang, Zhifei; Li, Guoxiang (September 2021). "A ten-faced hexangulaconulariid from Cambrian Stage 2 of South China". Journal of Paleontology. 95 (5): 957–964. Bibcode:2021JPal...95..957G. doi:10.1017/jpa.2021.25.
  11. ^ a b Chang, Shan; Clausen, Sébastien; Zhang, Lei; Feng, Qinglai; Steiner, Michael; Bottjer, David J.; Zhang, Yan; Shi, Min (September 2018). "New probable cnidarian fossils from the lower Cambrian of the Three Gorges area, South China, and their ecological implications". Palaeogeography, Palaeoclimatology, Palaeoecology. 505: 150–166. Bibcode:2018PPP...505..150C. doi:10.1016/j.palaeo.2018.05.039.
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  13. ^ Topper, Timothy P.; Guo, Junfeng; Clausen, Sébastien; Skovsted, Christian B.; Zhang, Zhifei (2019), "A stem group echinoderm from the basal Cambrian of China and the origins of Ambulacraria", Nature Communications, 10 (1): 1366, Bibcode:2019NatCo..10.1366T, doi:10.1038/s41467-019-09059-3, ISSN 2041-1723, PMC 6433856, PMID 30911013
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  18. ^ Chang, Shan; Feng, Qinglai; Zhang, Lei (August 2018). "New Siliceous Microfossils from the Terreneuvian Yanjiahe Formation, South China: The Possible Earliest Radiolarian Fossil Record". Journal of Earth Science. 29 (4): 912–919. Bibcode:2018JEaSc..29..912C. doi:10.1007/s12583-017-0960-0.
  19. ^ a b c d e Chang, Shan; Zhang, Lei; Feng, Qinglai (September 2025). "Diverse organic-walled microfossils from the basal Cambrian Yanjiahe Formation in the eastern Three Gorges area". Review of Palaeobotany and Palynology. 340 105361. Bibcode:2025RPaPa.34005361C. doi:10.1016/j.revpalbo.2025.105361.
  20. ^ a b c d Ahn, Soo Yeun; Zhu, Maoyan (November 2017). "Lowermost Cambrian acritarchs from the Yanjiahe Formation, South China: implication for defining the base of the Cambrian in the Yangtze Platform". Geological Magazine. 154 (6): 1217–1231. Bibcode:2017GeoM..154.1217A. doi:10.1017/S0016756816001369.

Further reading

  • P. Chen. 1984. Discovery of Lower Cambrian small shelly fossils from Jijiapo, Yichang, west Hubei and its significance. Professional Papers of Stratigraphy and Palaeontology 13:49-64
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