CGRG Bibliography of Canadian Geomorphology
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Author : Edgecombe, R.B.; Scott, D.B.; and Fader, G.B.J.
Date : 1999.
Title : New data from Halifax Harbour: paleoenvironment and a new Holocene sea-level curve for the inner Scotian Shelf.
Publication : Canadian Journal of Earth Sciences
Issue : 36(5):
Page(s) : 805-817.
Abstract
Two vibracores collected from Halifax Harbour allow reevaluation of the early postglacial history and part of a new sea-level curve for eastern Nova Scotia. An acoustically distinct seismic unit found throughout Halifax Harbour, but never previously sampled, occurs in the base of one core. Analysis of foraminiferal assemblages within this unit suggests estuarine conditions, not lacustrine as previously suggested. An in situ peat sample from the second core yields a date of 7770 ± 260 BP, and, based on the marsh foraminifera present, provides a sea-level point at -26.1 m. The foraminifera from the estuarine deposit yielded a date of 8480 ± 60 BP. The estuarine sediments are reddish, have a low organic content, and are very different from present-day estuarine sediments in this area, providing us a rare glimpse at early postglacial estuarine environments. This estuarine deposit represents deeper water than does the peat and indicates that sea level was higher prior to 7770 BP. Earlier papers suggested that sea level had been higher before 7000 BP, but the points presented here are the first data from this interval providing both spatial and temporal control on this critical interval of sea-level history. The new sea-level curve presented in this study, together with another recently published curve, shows two periods of emergence, one prior to 11 000 BP and another between 8000 and 7000 BP. The earlier emergence was probably the initial elastic rebound following ice removal; the second one may be the passage of the glacial forebulge predicted by theoretical models.
Bibliography of Canadian Geomorphology