AV俱乐部

Lake Banook in Dartmouth, Nova Scotia is a part of the historic Shubenacadie Canal system and has received much attention from city planners lately, however, the geological history of the lake and surrounding area has received relatively little attention. Here, reflection seismic, multibeam bathymetry and sediment cores have been used to explore the late glacial and Holocene history and evolution of this lake. Interpretations of high-resolution seismic data (10 kHz profiler) and six short sediment cores (maximum 1.2m) are presented, along with data on thecamoebian assemblages. Six seismic facies have been defined in the 10 m chick sediment column, interpreted from the base up to be glacial till, two glacilacustrine units, mass failures, and two Holocene units. One widespread unconformity and a higher terrace are interpreted as low-stand phenomena. The cores are correlated to seismic profiles and their interpretations. The cores sampled both Holocene units as well as both glacilacustrine units, generally across an unconformity. The light grayish brown glacilacustrine unites are finely laminated (varve-like) and are locally unconformably overlain by a reddish-brown, poorly stratified sandy diamict, overlain in turn by a series of soft, dark brown post-glacial muds and gyttja. Thecamoebians, freshwater protozoan microfossils, are abundant in the Holocene muds, but absent elsewhere in the cores. These microorganisms provide information regarding terrigenous and brackish water influence, as well as eutrophication and other anthropogenic influences.

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Pages: 60
Supervisor: Ned King, David Scott