Post-glacial paleo-oceanography of Emerald Basin, Scotian Shelf

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Vilks, Gustavs, Rashid, M. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1976
• Subjects: General Earth and Planetary Sciences; Emerald Basin; Planktonic foraminifera
• Online Access: http://dx.doi.org/10.1139/e76-128; http://www.nrcresearchpress.com/doi/pdf/10.1139/e76-128

Two sediment cores taken from Emerald Basin, Nova Scotia are discussed in terms of organic geochemistry and foraminifera. The analytical results are used to infer changes in the marine environment in Emerald Basin during the last 15 000 y.The fine sediments contained relatively low amounts of organic carbon, plant pigments, sulphides with respect to total sulphur, and only background values of methane. The data indicate that the bottom of the Basin has been well oxygenated since the Late Wisconsin, including the times of lowest sea level. The foraminiferal assemblages varied from estuarine–nearshore fauna in the older sediments to the outer shelf-normal marine faunas in the surface sediments. Planktonic foraminifera were found in all levels of the cores.The faunal evidence indicates that during the Late Wisconsin sea-level minimum and the period of glacial waning, the bottom salinities of the Basin were in the order of 20‰. Emerald Basin was connected to the ocean via a wide but shallow sill that allowed the exchange of Basin waters with only relatively diluted surface waters of the ocean.