Atafaitafa Fm. (70 m) at Ain Khala (Djebel Tahinaouine) (Devonian to of Algeria)

Where: Algeria (26.4° N, 7.3° E: paleocoordinates 67.9° S, 53.5° E)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Atafaitafa Formation, Lochkovian to Lochkovian (419.2 - 407.6 Ma)

• Ref. 7455 interprets age of formation as a whole as Gedinnian-Siegenian. The material is from about 60 m above the base of the formation, apparently only 10 m or so from the top.

• group of beds-level stratigraphic resolution

Environment/lithology: transition zone or lower shoreface; argillaceous sandstone and siltstone

• This collecting locality is on western edge of outcrop belt. Formation is thicker and more argillaceous toward the west. According to paleogeographic map in ref. 7455, the collecting localities for this formation would be some 500-700km to the present-day SE of the inferred Lower Devonian shoreline. The shoreline, according to this map, migrated some 1000km or from the SE to the NW (present-day coordinates) during the Llandovery to Gedinnian timespan.

•SEP environmental call based on given lith. and basic geological data provided by source ref. (PBDB 7455)

• Formation as a whole [ref. 7455]: "siltstones, silty shale, argillaceous sandstones, and massive sandstones". According to stratigraphic column, this collection comes from a level at the transition between the "gres et quartzites" below and the "facies argilo-greseux" above.

Primary reference: P. Dubois and P. Mazelet. 1964. Stratigraphie du Silurien du Tassili N'Ajjer. Bulletin de la Societe Geologique de France (Serie 7) 6(4):586-591 [M. Foote/M. Foote/M. Foote]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 27169: authorized by Michael Foote, entered by Michael Foote on 21.11.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

Gastropoda
 Bellerophontida - Plectonotidae
"Bucanella cf. derbyi" = Plectonotus derbyi
"Bucanella cf. derbyi" = Plectonotus derbyi Clarke 1899 snail
Bivalvia
 Modiomorphida - Modiomorphidae
Modiomorpha sp. Hall and Whitfield 1869 clam
Strophomenata
 Orthotetida - Orthotetidae
"Hipparionyx cf. minor" = Hipparionix
"Hipparionyx cf. minor" = Hipparionix
Rhynchonellata
 Rhynchonellida - Rhynchonellidae
Trilobita
 Phacopida - Homalonotidae
Burmeisteria sp. Salter 1865 trilobite