Clarkeia-Salopina Community, Pridoli, Porz ar Vouden sect., Armorican Massif (Silurian of France)

Where: France (48.2° N, 4.6° W: paleocoordinates 55.8° S, 38.3° E)

• coordinate based on political unit

• local area-level geographic resolution

When: Pridoli (423.0 - 419.2 Ma)

• member-level stratigraphic resolution

Environment/lithology: marine; sandstone and black shale

• General statement of Central Armorican trough during Llandovery through Lochkovian: "depositional patterns typical of a platform environment...Silurian is mainly an alternating succession of unfossiliferous sandstones and locally fossiliferous black shales...The arenaceous deposits are probably related to the eustatic regression and corresponding high sedimentation rate during the Pridolian and Lochkovian...Outside the A. Massif the Pridoli-Lochkovian succesion in Artois (boreholes) is characterized by shallow marine shales and limestones overlain by areanceous deposits that correspond to the Early Devonian transgression."

•For this Community: "moderately rough water inferred from highly disarticulated nature of most of the specimens...typical low diversity, high dominance unit on a silty bottom...outer BA 2.."

• General statement: "In Brittany there are two kinds of black shale and limestone deposits during the Llandovery to lowermost Devonian interval: (1) black shales (commonly described as sapropelites) are widespread in space and time and (2) black, micritic limestones or argillaceous limestones are restricted to two localities in the eastern part of the Armorican Massif. The black shales are very rich in organic matter and locally contain detrital mica, pyrite, and nodules..."

•For this community: "The sediment is a quartzwacke with typical high energy storm wave pattern of hummocky cross-stratification indicative of platform deposit. The coexistence of wave crossbedding with symmetrical ripples is indicative of shallow water, probably above normal wave base."

Collection methods: Table 18.4, which includes specimen counts for brachiopods. Based on original report (PBDB. ref. 7249), material listed here is mainly from levels 30-31 in the section. At levels 1-6 and 33 are some mollusks, which I am including here. (Expanding the levels evidently does not change the age from Lower Pridolian.)

Primary reference: P. R. Racheboeuf. 1999. Lower Silurian to Lower Devonian communities from the Armorican Massif (western France) and Artois (northern France). In A. J. Boucot, J. D. Lawson (eds.), Paleocommunities--a case study from the Silurian and Lower Devonian 260-270 [M. Foote/M. Foote/P. Wagner]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 26108: authorized by Michael Foote, entered by Michael Foote on 04.10.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Trilobita
 Phacopida - Homalonotidae
Homalonotidae indet.
Homalonotidae indet. Chapman 1890 trilobite
Cephalopoda
 Orthocerida - Arionoceratidae
Arionoceras arion, Parakionoceras sp.
Parakionoceras sp. Foerste 1928
Bivalvia
 Autobranchia -
Pterioida indet.
Pterioida indet. Newell 1965 clam
Rhynchonellata
 Orthida -
Enteletacea indet.
Enteletacea indet. Waagen 1884
 Orthida - Draboviidae
Salopina missendenensis, ? Salopina sp.
? Salopina sp. Boucot 1960
 Rhynchonellida -
Rhynchonellida indet.
Rhynchonellida indet. Kuhn 1949
small
 Rhynchonellida - Eatoniidae
Clarkeia puilloni
Strophomenata
 Strophomenida - Leptostrophiidae
Leptostrophia voudenensis