Foraminiferal distribution and sedimentary facies on the Grand Banks of Newfoundland

Abstract

The southern part of the Grand Banks can be divided into three sedimentary regions. The north western region is dominated by gravel-size material; this is probably a reworked glacial sediment and its limit may indicate the seaward edge of the Quaternary ice sheet. The other regions are both dominated by sand-size pro-glacial material reworked in post-glacial times. The southwestern region includes a large area of finer sediment, which shows the highest density of foraminiferal tests. Dominant lineations indicate the probable influence of the Labrador Current and the Gulf Stream in the distribution of sediments.On the Tail of the Bank, an inverse relationship is commonly present between the density of the benthonic tests and the grain-size of the sediment. Of the 88 species present in the benthonic assemblage, 31 occur in 30% or more of the stations and only 5 occur in more than 90% of the stations. Islandiella islandica (Nørvang) is the most abundant species. The distribution of the living/total ratio in the benthonic Foraminifera is erratic, but particular areas of significantly high or low ratios may be related to different rates of sedimentation. The distribution of the planktonic assemblage, dominated by Globigerina pachyderma (Ehrenberg), is apparently controlled mainly by the movement of the Labrador Current waters. The percentage of planktonic tests in the total foraminiferal population decreases sharply on the shallow plateau, inward from the edge of the Bank.

Relict Carbonate-Rich Sediments on Southwestern Grand Bank, Newfoundland

“…This conclusion conflicts with that of Sen -Gupta and McMullen (1969), who inferred that the glacial front extended into the northern Fart of the study area and glacial outwash contributed heavily to the sediment to the south.…”

“…Previous analyses of surface sediments have shown the presence of large boulders and gravel on northern and eastern Grand Bank, while the southern and southeastern sections contain sand, gravelly sand, and muddy sand (Litvin and Rvachev 1962;Avilov 1965;Sen Gupta and McMullen 1969). Emery and Uchupi (1972) concluded that these finer sediments in the southern area may have been deposited by glacial melt waters during the early Holocene.…”

Studies of Benthonic Foraminifera in the Restigouche Estuary: 1. Faunal Distribution Patterns near Pollution Sources

“…In the laboratory, the preserved sediment sample was flushed into a 100 ml cylinder for determination of wet volume. The sample was then washed through a number 230 sieve (0.063 mm openings), dried at 60°C and floated in a solution of bromoform and acetone (Gibson and Walker, 1967;Sen Gupta and McMullen, 1969) . The floats were dried at room temperature and foraminifera species were identified and counted on a standard Curtin 14401 slide.…”

Interactions between substrate and temperature preference in adult American plaice (Hippoglossoides platessoides)

“…The substrates used were: gravel which consisted of small pebbles of 1.0 to 2.0 mm diameter and larger 2 to 3 cm stones; sandy gravel which was composed of one-third sand and two-thirds gravel (by volume); gravelly sand which was mostly sand and was composed of two-thirds sand and one-third gravel; sand which was composed of particles 0.15 to 1.0 mm in diameter; and mud which is a very fine silty material of 0.15 to 0.25 mm grain size. These substrates were made following the descriptions of Sen Gupta and McMullen (1969) of the major sediment types on the Grand Bank. The components of these substrates were mainly collected from the bank using grabs, except for some gravel and sand collected on local beaches.…”