The Yanjiahe Formation is an Ediacaran to Cambrian fossiliferous geologic formation found in South China.
Dating
The Yanjiahe Formation has been dated through various methods. The top of the formation is dated at and using radiometric dating on ash beds within the area. Likewise, the base of the formation has been dated to between to through carbon isotopic correlations.
Beds
The Yanjiahe Formation consists of five beds. Every bed within the formation contains fossil material.
The beds are as follows, listed by ascending age:
- Bed 1 is characterized by basal dolomitic conglomerates, with banded black cherts.
- Bed 2 is mostly consists of siliceous phosphatic dolostone, with flat pebble conglomerates.
- Bed 3 is characterized by various shales, with the presence of siliceous-phosphatic nodules.
- Bed 4 is composed of carbonaceous limestones.
- Bed 5 is characterized by cherts and siliceous phosphatic dolostone, with flat pebble conglomerates.
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.
Cnidaria
Chancelloriida
Deuterostome
Ecdysozoa
Lophotrochozoa
Porifera
incertae sedis
Flora
Microorganisms
Undescribed
See also
References
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