The distribution of major species of benthic foraminifera collected from the upper portion of box cores and piston core-tops follows several major trends. Arenaceous assemblages occur in the liquid surface layer of silty mud, which is normally missed by the piston corer. Below this layer, the inner-shelf assemblages are dominated by calcareous species, such as Islandiella helenae Feyling-Hanssen and Buzas and Elphidium excavatum (Terquem) forma alba Feyling-Hanssen. In Lake Melville, the surface and subsurface layers have similar faunas, dominated by Reophax fusiformis (Williamson) and Saccammina atlantica (Cushman).
In comparison with other regions, the assemblages show very close affinity with Hudson Bay and Gulf of St. Lawrence faunas. The depth range of foraminiferal and molluscan species on the Labrador Shelf is greater than elsewhere. For example, in the Labrador Shelf waters, Ammotium cassis (Parker) is common in waters as deep as 360 m. It is considered to be a coastal species along the western North Atlantic to the south, and in the Gulf of St. Lawrence, it is found most commonly in depths of < 10 m. The occurrence of A. cassis in deeper water on the Labrador Shelf is associated with the relatively high content of suspended particulate matter along the bottom of the deeper basins.
This article is based on a paper presented at a symposium entitled “Quaternary Benthic Foraminifera of North American Continental Margins,” held in November 1980.
- Geological Society of America