Takuan Formation (Huanggexi Member) at Huanggexi, Daguan Co., NE Yunnan Prov. (Silurian of China)

Where: Yunnan, China (27.7° N, 103.9° E: paleocoordinates 10.2° N, 128.6° E)

• coordinate based on political unit

• local area-level geographic resolution

When: Huanggexi Member (Takuan 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. Revised usage of Takuan Formation to restrict it so Songkan, Huanggexi, and Sifengya units (from bottom to top). Daluzhai is regarded as synonym of Xiushan Formation. "The age of the [Huanggexi Member] is early late Llandovery."

• member-level stratigraphic resolution

Environment/lithology: marine; gray, argillaceous limestone and sandy, calcareous mudstone

• Correlation chart indicates BA3 assignment based on shelly fauna for the Takuan formation, and graptolite-based ba3 for "Songkan Member."
• "The Huanggexi Member is 145 m thick and consists of dark-gray, thick-bedded and massive, argillaceous limestone, and crystalline limestone interbedded wiht calcareous, sandy mudstone and quartzitic 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 27850: authorized by Michael Foote, entered by Michael Foote on 14.01.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

Anthozoa
 Heliolitida - Halysitidae
Catenipora sp. Lamarck 1816 tabulate coral
Halysites sp. von Waldheim 1813 tabulate coral
 Heliolitida - Heliolitidae
Heliolites sp. Dana 1846 tabulate coral
 Heliolitida - Proporidae
Propora sp. Milne-Edwards and Haime 1849 tabulate coral
 Favositida - Favositidae
Favosites sp., "Palaeofavosites sp." = Paleofavosites
Favosites sp. Lamarck 1816 tabulate coral
"Palaeofavosites sp." = Paleofavosites Twenhofel 1914 tabulate coral
 Cystiphyllida - Cystiphyllidae
Cystiphyllum sp. Lonsdale 1839 horn coral
 Cystiphyllida - Palaeocyclidae
 Rugosa -
 Stauriida - Lykophyllidae
Pycnactis sp. Ryder 1926 horn coral
 Stauriida - Streptelasmatidae
Gastropoda
 Euomphalina - Elasmonematidae
Discordichilus globrous Xi and Yu 1990 snail
corrected from "Discordochilus" [entered as Discordichilus glabrous]
 Murchisoniina - Loxonematidae
Loxonema sp. Phillips 1841 snail
Rhynchonellata
 Orthida - Dalmanellidae
Dalmanellidae indet. Schuchert 1913
 Atrypida -
Zygospiraella sp. Nikiforova 1961
 Pentamerida - Pentameridae
Trilobita
 Phacopida - Encrinuridae
Encrinuroides sp. Reed 1931 trilobite
 Proetida - Aulacopleuridae