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TitleStable isotope evidence for groundwater seepage into Kempenfelt Bay, Lake Simcoe
AuthorLongstaffe, F J; Lewis, C F M; King, J W; Heil, C W, Jr.; Hubeny, J B; Goodyear, D R; Slattery, S R; Macdonald, R A
Source51st Annual conference on Great Lakes research, IAGLR 2008, book of abstracts; by International Association for Great Lakes Research; 2008 p. 91
LinksOnline - En ligne (IAGLR 2008, book of abstracts)
Alt SeriesEarth Sciences Sector, Contribution Series 20080002
Meeting51st Annual Conference on Great Lakes Research; Peterborough; CA; May 20-23, 2008
Mediapaper; on-line; digital
File formatpdf
AreaLake Simcoe; Kempenfelt Bay
Lat/Long WENS -80.0000 -79.5000 44.5000 44.2500
Subjectshydrogeology; stable isotope studies; groundwater
ProgramEnhancing resilience in a changing climate
AbstractPorewater was extracted at 10cm intervals from two piston cores collected from Lake Simcoe, and its oxygen- and hydrogen-isotope compositions measured. The first core (44.38°N, 079.67°W; water depth, 24m; core length, 5.12m) was taken near the head of Kempenfelt Bay, where groundwater seepage into Lake Simcoe has been suggested from seismic reflection data. The second core (44.49°N, 079.42°W; water depth, 21m; core length, 7.61m) was taken from the main basin of Lake Simcoe. The d18O and dD values of porewater from the second core range from 7.8 to 6.9o/oo and -61 to -52o/oo, respectively, decreasing gradually towards the bottom of the core. The isotopic compositions cluster slightly to the right of the Great Lakes Regional Meteoric Water Line, reflecting the evaporative enrichment known for Lake Huron and Lake Simcoe. A much wider range of d18O (-11.9 to -7.6o/oo) and dD (-85 to -57o/oo) values was obtained for porewater from the Kempenfelt Bay core. These results describe a mixing line between regional groundwater (d18O = -11.3o/oo, dD = -81o/oo) and porewater from the main basin of Lake Simcoe. Groundwater dominates the porewater above 3m. The interval between 3 and 4m is dominated by lake water. Below that, mixing has occurred between the two reservoirs.