Chenxiacun Formation, Lower Member, Cangshan, SW of Hanshan, Anhui Province (Silurian of China)

Where: Anhui, China (34.0° N, 118.0° E: paleocoordinates 23.1° S, 123.1° E)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Chenxiacun Formation, Telychian (438.5 - 433.4 Ma)

• Except where otherwise stated, ref. 7624 uses Lower Silurian as equivalent to Llandovery, Middle Silurian as equivalent to Wenlock, and Upper Silurian as equivalent to Ludlow plus Pridoli. "Qian [1978] subdivided the formation into two parts. Fossils from the lower part include...Cyclonema sp., which suggests a Late Llandoveyr age, and may be correlated with the Lojoping Fm. the fossils from the upper part include...Pristiograptus cangshanensis. The graptolite is similar to Monoclimacis fenggangensis from the Leijiatun Formation of NE Guizhou, which suggests a later Upper Llandovery age. This formation was previously included with the underlying Kaochiapien Fm." Correlation chart suggest correlation with turriculatus zone for lower member and late turriculatus zone through rest of Llandovery for upper member.

• member-level stratigraphic resolution

Environment/lithology: marine; green, yellow, calcareous siltstone and limestone

• Correlation chart indicates BA 3 position for this unit.
• "The unit consists mainly of yellowish-green, calcareous siltstone with interbedded thin limestone. Some fine-grained sandstone and shale occur in the lower part. The unit is 107 m thick. Fossils are abundant, and chiefly shelly. Qian subdivided the formation intwo the parts. The lower part consists of siltstone, with some limestone, whereas the upper part is chiefly shale with some interbedded siltstone."

Primary reference: E.-z. Mu, A. J. Boucot, X. Chen and J.-y. Rong. 1986. Correlation of the Silurian rocks of China. In A. J. Boucot and W. B. N. Berry (eds.), Geological Society of America Special Paper 202:1-80 [M. Foote/M. Foote/P. Wagner]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 27737: authorized by Michael Foote, entered by Michael Foote on 07.01.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

 Favositida - Favositidae
Favosites gothlandicus Lamarck 1816 tabulate coral
Mesofavosites sp. Sokolov 1951 tabulate coral
 Heliolitida - Heliolitidae
Helioplasmolites minor tabulate coral
 Heliolitida - Halysitidae
 Stauriida - Stauriidae
Ceriaster minor horn coral
 Cystiphyllida - Tryplasmatidae
 Clathrodictyida - Clathrodictyidae
Clathrodictyon vesiculosum Nicholson and Murie 1878 stromatoporoid sponge
 Cyathocrinida - Petalocrinidae
 Atrypida -
Zygospiraella sp. Nikiforova 1961
 Atrypida - Atrypinidae
 Oncocerida - Nothoceratidae
Yichangoceras sp. Chen et al. 1981
 Orthocerida - Dawsonoceratidae
 Euomphalina - Platyceratidae
Cyclonema sp. Hall 1852 snail
 Corynexochida - Styginidae
Scutellum (Thysanopeltella) sp. Pusch 1833 trilobite