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Alegret, Ortiz & Kaminski (eds.), 2012. Ninth International Workshop on Agglutinated Foraminifera, Abstract Volume
A “Flysch-type” agglutinated foraminiferal assemblage from the Lower
Carboniferous black shales of northern Saudi Arabia
Michael A. KAMINSKI 1,2 , G. Wyn HUGHES 1,3 and Nigel HOOKER 3
1 Earth Sciences Department, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi
Arabia
2 Department of Earth Sciences, University College London, Gower Street, London, WC1E 6BT,
United Kingdom
3 Geological Technical Services Division, Saudi Aramco, Box 10646, Dhahran, 31311, Saudi Arabia.
e-mail: kaminski@kfupm.edu.sa
A new assemblage of agglutinated foraminifera is described from Lower Carboniferous black
shales of the Berwath Formation recovered in an exploration well drilled in northern Saudi
Arabia. The recovered sediment consists of bioturbated black shale with stringers of thin
siltstone and sandstone, and is the age equivalent of the Barnett Shale of Texas. The recovered
assemblage comprises of exclusively agglutinated foraminifera characterized by diverse
morphogroups, including free-living tubular forms that can be abundant. In this respect, the
assemblage can be compared with the “flysch-type” assemblages described from the
Cretaceous and Paleogene of the North Atlantic and western Tethys. The assemblage from
Saudi Arabia displays higher diversity than previously described “Kinderhookian”
agglutinated assemblages from the Lower Carboniferous shales and limestones in North
America.
The key feature that distinguishes the Saudi Arabian, Berwath Formation assemblage
from the “Kinderhookian” and “Osagian” agglutinated assemblage described from North
America (Conkin, 1961) is the presence of diverse free-living lituolids and trochamminids and
the rarity of forms that grow attached to a hard substrate such as Tolypammina. Previously
reported species of Ammobaculites from the North American assemblages contain typical
Ammobaculites species that are round in cross-section such as A. pyriformis Gutschick &
Treckman, A. gutschicki Conkin, or A. beveridgei Conkin & Conkin. In the present material,
some species belonging to the genus Ammobaculites or Sculptobaculites are strongly
compressed, to the point of closely resembling the Late Cretaceous to Cenozoic genus
Glaphryammina. This is the first report of diverse compressed lituolids from the Lower
Carboniferous. Even more striking is the presence of trochamminids with petaloid, digitate,
and radially elongated chambers that even possess structures akin to primitive tubulospines.
The obvious isomorphism between the Lower Carboniferous trochamminids and some Lower
Cretaceous planktonic foraminiferal genera such as Clavihedbergella and Leupoldina is a
topic of interest from an evolutionary point of view. Several species will be described as new,
and others are left for now in open nomenclature. The finding of new Lower Carboniferous
lituolids and trochamminids with distinctive “advanced” morphologies has implications for
any hypothesis regarding the evolution and functional morphology of benthic foraminifera in
dysoxic environments.
Reference:
Conkin, J.E. 1961. Mississippian smaller foraminifera of Kentucky, southern Indiana, northern
Tennessee, and southcentral Ohio. Bulletins of American Paleontology, 43 (196), 368 pp.
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