<p> The Paleozoic bedrock surface of southern Ontario is dissected by an interconnected system of buried bedrock valleys that are infilled with thick successions of glacial, interglacial and fluvial sediments. These valleys can be several kilometers wide, reach depths of up to 250m and the coarse-grained units are known to host significant local and regional groundwater aquifers.</p> <p> Two buried bedrock valleys located near the Niagara Escarpment in the Region of Halton were under investigation in the fall of 1999 for their potential to host additional municipal groundwater aquifers to supply drinking water to the towns of Milton and Georgetown. Detailed logging of sediment recovered from eleven continuously-cored boreholes, drilled within the Georgetown and Milton bedrock valleys, forms the basis for this study. Four distinct facies types were identified within the borehole cores including sand, gravel, fine-grained sediment and diamict (sand-rich, mud-rich and clast-rich). These four facies types were used to subdivide the cores into six stratigraphic units based on textural characteristics and stratigraphic position. These six units form a stacked succession of aquifers and aquitards within the valley infill with two stratigraphic units being identified as potential municipal aquifers.</p> <p> The Georgetown buried bedrock valley contains narrow bedrock channel interpreted to have been fluvially incised, lying within a broader flat-bottom valley likely formed by glacial scouring of the bedrock. It is feasible that regional bedrock jointing created a zone of weakness that was later exploited by a drainage network. The valley infill sediments record the approach of the Laurentide Ice Sheet into southern Ontario during the Early to Mid-Wisconsin, and the subsequent overriding of the area during the Late Wisconsin period.</p> / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19537 |
| Date | 08 1900 |
| Creators | Meyer, Patricia Anne |
| Contributors | Eyles, Carolyn H., Geography and Geology |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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