| Title | Geochemistry of southern Ontario Quaternary sediments |
| Download | Download (whole publication) |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Knight, R D ;
Bajc, A F; Kjarsgaard, B A; Crow, H; Stepner, D A J; Sharpe, D R; Russell, H A J |
| Source | Regional-Scale Groundwater Geoscience in Southern Ontario: An Ontario Geological Survey, Geological Survey of Canada, and Conservation Ontario Geoscientists Open House; by Russell, H A J; Ford, D; Holysh, S; Priebe, E H; Geological Survey of Canada, Open File 8528,
2019 p. 18, https://doi.org/10.4095/313589  Open
Access |
| Year | 2019 |
| Alt Series | Ontario Geological Survey, Open File Report 6349 |
| Publisher | Natural Resources Canada |
| Meeting | Regional-Scale Groundwater Geoscience in Southern Ontario: Open House; Guelph; CA; February 27-28, 2019 |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Regional-Scale Groundwater
Geoscience in Southern Ontario: An Ontario Geological Survey, Geological Survey of Canada, and Conservation Ontario Geoscientists Open House |
| File format | pdf |
| Province | Ontario |
| NTS | 30; 31B; 31C; 31D; 31E; 31G; 40; 41A; 41G; 41H/03; 41H/04; 41H/05; 41H/06; 41H/12; 41H/13 |
| Area | Southern Ontario; Great Lakes |
| Lat/Long WENS | -84.0000 -74.0000 46.0000 41.5000 |
| Subjects | hydrogeology; geochemistry; stratigraphy; Health and Safety; groundwater; aquifers; sediment geochemistry; boreholes; core samples; x-ray fluorescence analyses; mass spectrometer analysis; provenance;
bedrock geology; lithology; sedimentary rocks; carbonates; dolomites; limestones; calcium geochemistry; magnesium geochemistry; glacial deposits; tills; Newmarket Till; Catfish Creek Till; Human health; Phanerozoic; Cenozoic; Quaternary; Paleozoic;
Precambrian |
| Program | Groundwater Geoscience Aquifer Assessment & support to mapping |
| Released | 2019 02 08 |
| Abstract | Geochemical analysis constrained by stratigraphic units with detailed sampling of continuous core is rare in glaciated basins. The up to 200 m plus thickness of surficial sediment cover across 74,000
km2 area of southern Ontario (S-ON) and the presence of many hundred continuously cored boreholes provided an opportunity to investigate the chemostratigraphy of a large glaciated basin. The S-ON basin setting over Phanerozoic sedimentary carbonate
and shale, and bounded by igneous and metamorphic rocks of Canadian Shield, provides an ideal setting for geochemical provenance studies and methods development. Geochemical analysis of 3,815 surficial sediment samples from 53 boreholes have been
analysed via portable X-ray fluorescence spectrometry (pXRF) and traditional laboratory geochemical analytical methods.
Comparison of geochemistry from ICP-ES/MS and with pXRF indicates good characterization of the basin chemistry by the
laboratory and pXRF analysis methods. Significant changes in elemental concentrations within individual cores are identified in multiple contexts, i) across formation contacts, ii) internally within formations, iii) absence of change across formation
boundaries. These likely represent changes in depositional processes and provenance between Precambrian Shield and Paleozoic sources. Changes in elemental concentrations are commonly not correlated between boreholes at either the formation or sub
formation level. On a regional scale, the geochemical ratio of CaO+MgO/SiO2+Al2O3 provides a Provenance Indicator (PI) to determine elemental contributions from a Paleozoic carbonate source relative to contributions from Precambrian Shield sources.
As calcium and magnesium occurs in markedly higher concentrations in Paleozoic carbonate rocks, a higher PI value reflects greater input of material derived from these Paleozoic sedimentary rocks. Examination of the Newmarket Till using this PI shows
a correlation between the amount of carbonate-derived material in the till-matrix and sampling distance relative to the shield margin indicates the deposition of increasingly carbonate-rich surficial sediments to a maximum at approximately 80-100 km
south of the Shield-margin. Additionally to the PI, a geochemical distinction is observed between sediments deposited east (carbonate dominated) and west (dolomite dominated) of the Niagara Escarpment. Elevated MgO and CaO west of the Niagara
Escarpment (Catfish Creek Till) indicates sourcing of Silurian dolomite, whereas east of the Escarpment (Newmarket Till) CaO-rich till is due to sourcing of Ordovician limestone.
The geochemical study of Quaternary sediments in southern Ontario
has not found any evidence of elemental concentrations that might adversely affect groundwater quality and human health. |
| Summary | (Plain Language Summary, not published)
Volume of abstracts for Ontario Geological Survey and Geological Survey of Canada groundwater geoscience Open house with Conservation Ontario. |
| GEOSCAN ID | 313589 |
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