Yulungssu Formation, Liaojiaoshan Area, near Qujing, Yunnan Province (Silurian of China)

Where: Yunnan, China (25.5° N, 103.8° E: paleocoordinates 9.1° N, 129.9° E)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Yulungssu Formation, Ludlow (427.4 - 423.0 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. "Wu (1977) records Warburgella rugulosa sinensis at the base of the formation, and considers that it is indicative of an Early Gedinnian age. But brachiopods...include [list], all extending from the underlying Miaokao Fm., so the we prefer to correlate the Y. Fm. with the uppermost Silurian rather than with the Devonian. In the upper part of the Y. Wang (1981) records crispus zone, Ludlow age conodonts. The similarity of the Qujing region, Upper Silurian shelly faunas suggests that they are all of Ludlow age."

• formation-level stratigraphic resolution

Environment/lithology: marine; mudstone and siltstone

• Correlation chart shows BA1-3 based on shelly faunas. Formation interpreted as mixed marine, brackish, and freshwater (based on corresponding fossils).
• "Black shale occurs at the bottom of this formation, which consists mainly of a series of mudstones and siltstones. It is gradationally overlain by thick-bedded sandstone of the Cuifengshan Fm. [Devonian]...The formation is 330 m thick in the type locality."

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 27912: authorized by Michael Foote, entered by Michael Foote on 16.01.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

Galeaspida
 Polybranchiaspidiformes - Polybranchiaspididae
Trilobita
 Proetida - Proetidae
"Warburgella rugulosa" = Warburgella (Rugulites) rugulosa
"Warburgella rugulosa" = Warburgella (Rugulites) rugulosa Alth 1874 trilobite
Rhynchonellata
 Spiriferida - Delthyrididae
 Athyridida - Retziellidae
"Protathyrisina plicata" = Retziella
"Protathyrisina plicata" = Retziella
 Athyridida - Athyrididae
 Rhynchonellida - Hebetoechiidae
Cephalopoda
 Oncocerida - Acleistoceratidae
Worthenoceras sp. Foerste 1930
Euryrizoceras sp. Foerste 1935
Ectocyrtoceras sp. Foerste 1930
Byronoceras sp. Foerste and Savage 1927
Yunnanoceras sp. Chen et al. 1981