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Alegret, Ortiz & Kaminski (eds.), 2012. Ninth International Workshop on Agglutinated Foraminifera, Abstract Volume
Palaeobiogeography of Late Cretaceous agglutinated foraminifera in the Arctic,
Atlantic and Tethyan regions
Eiichi SETOYAMA 1 , Michael A. KAMINSKI 2 , Jarosław TYSZKA 1 and Wiesława
RADMACHER 1
1
Polish Academy of Sciences, Institute of Geological Sciences, Cracow Research Centre, BioGeoLab,
Senacka 1, 31-002 Kraków, Poland.
2
Earth Sciences Department, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi
Arabia.
e-mail: ndsetoya@cyf-kr.edu.pl
The wide geographic distribution of Late Cretaceous deep-water agglutinated foraminifera
(DWAF) has been demonstrated by various studies (e.g. Kuhnt et al., 1989; Kuhnt and
Moullade, 1991) in the Tethyan–Atlantic regions. Recently, we analysed Late Cretaceous
foraminiferal assemblages of the southwestern Barents Sea (Setoyama et al., 2011a, b) and the
Lomonosov Ridge (Setoyama et al., 2011c), whose taxonomy and compositional data were
never published before. The taxonomic data from these studies provided us an opportunity to
investigate the geographic extent of the cosmopolitan DWAF in the high palaeolatitudes, and
also the affinity between the fauna of circum-Arctic regions of which on the Eurasian side
only a little is from Western Siberia. In order to estimate the faunal similarity between
different regions throughout the Tethyan–Atlantic–Arctic transect, the data set was compiled
from direct observation of assemblages (the Lomonosov Ridge, SW Barents Sea, Norwegian
Sea and Labrador Sea) and data from published literature from 17 regions. It consists only of
the presence/absence data so as to discount palaeoenvironmental signatures. Data from the
SW Barents Sea and the Norwegian Sea are biostratigraphically calibrated using dinocysts.
Although the data set includes only the presence/absence data, the agglutinated
foraminiferal assemblages are distinguished largely by environments and regions by cluster
analysis suggesting that some taxa are confined to certain environments and possibly
physically isolated areas. Clustering of the assemblages is less ambiguous on the basis of the
genus data than the species data. The results of correspondence analysis shows a clear
separation of the shallow-water Arctic assemblages, the chalk fauna, the Western Siberian
fauna and the Atlantic–Tethyan deep-water fauna, whose subgroups largely correspond to the
classical DWAF biofacies (Kuhnt et al., 1989). Very limited or no marine connections
between the Arctic (Canada, North America and Lomonosov Ridge), North Atlantic and
Western Siberia over the Barents Sea are inferred from the separation of the Canadian–North
American and the Lomonosov Ridge Arctic assemblages from the Western Siberian and the
SW Barents Sea fauna. A majority of calcareous-agglutinated foraminiferal species are
confined to the Tethyan and Atlantic chalk facies where calcareous benthic and planktic
foraminifera are also often well-preserved. The availability of calcium carbonate and the
corrosiveness of pore waters, thus, appear to be major controlling factors imposing on
calcareous-cemented taxa the limited palaeogeographic distribution and occurrence in the
fossil records of the northern high latitudes. Although the variability in food influx and
oxygenation of bottom waters exert influence on the composition of assemblages as reflected
by DWAF biofacies, their effect on the palaeobiogeographic distribution of Late Cretaceous
DWAF is rather local. In contrast to calcareous-cemented taxa, organic cemented DWAF are,
in general, cosmopolitan, and it seems that they occur wherever environments are tolerable for
them.
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