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TitleThe Annapolis Valley - a complex glacial history that bears on groundwater resources
AuthorBolduc, A; Paradis, S J; Stea, R R; Pullan, S; Ross, M
SourceGAC-MAC-CSPG-CSSS Halifax 2005, building bridges - across science, through time, around the world: abstracts/AGC-AMC-SCGP-SCSS Halifax 2005, Jeter des ponts entre les disciplines scientifiques, les époques, et unifier le monde : recueil des résumés; GAC-MAC-CSPG-CSSS Joint Meeting, Abstracts vol. 30, 2005 p. 14-15
Alt SeriesEarth Sciences Sector, Contribution Series 2004303
MeetingGAC-MAC-CSPG-CSSS Halifax 2005, building bridges - across science, through time, around the world / AGC-AMC-SCGP-SCSS Halifax 2005, Jeter des ponts entre les disciplines scientifiques, les époques, et unifier le monde; Halifax; CA; 2005
File formatpdf
ProvinceNova Scotia
AreaAnnapolis Valley
Lat/Long WENS -65.0000 -64.5000 45.2500 45.0000
Subjectshydrogeology; surficial geology/geomorphology; aquifers; bedrock aquifers; glaciation; ice flow; groundwater; recharge rates; bedrock geology; groundwater flow
AbstractAs part of a regional hydrogeology mapping project by the Geological Survey of Canada, we have revisited the Quaternary successions
located in the Annapolis Valley of Nova Scotia. Detailed mapping in the valley is necessary to clarify aspects of its glacial-deglacial history. It is also crucial to understand the 3D architecture of the surficial deposits as it impacts directly on groundwater recharge and natural protection of the bedrock aquifer. The Annapolis Valley, tucked between North and South Mountains, has had a complex glacial -
deglacial history that relates to the overall regional story of Nova Scotia. The first ice flow recognized in the valley, associated with the
Late Wisconsinan glacial maximum, is southward (Escuminac phase). This is recorded on outcrops on both North and South Mountains but is absent from the soft rocks of the valley floor. Ice flow reversals have been documented as Nova Scotia-based ice caps in the Maritimes begin to flow independently during the Scotian phase. The event is recorded by north-trending striae on South Mountain, as well as by the presence of South Mountain erratics on North Mountain. Finally, the Chignecto phase (westward lateglacial ice streaming) is recognized in the Annapolis Valley by west trending landforms partly buried under marine and/or glaciolacustrine clay and by the presence of a few scattered striae observed on the flanks and top of the surrounding mountains. The western end of the valley has a well-defined marine limit at 30-40 m ASL but the eastern end is less well defined. Small erosional benches have been identified in the eastern part of the valley, which has yet to be fully evaluated in terms of marine limit. The surficial story is supplemented by limited subsurface information. Evidence of probable buried valleys is found in borehole data and these were the target of geophysical investigations. We have not yet been able to resolve the stratigraphy in those valleys, one issue being that the velocity of the altered bedrock (Wolfville Formation) is similar to the velocity of the local till, making it hard to distinguish them using seismic methods. Nonetheless, all the data acquired will be used to build a 3D geologic model for the Valley, surficial and bedrock, that will serve as the basis to understand groundwater flow, recharge and natural protection. This model will also serve as a decision making tool for groundwater management by various stakeholders.