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Géochimie des sédiments glaciaires dans la province précambrienne de Grenville, dans le sud-est de l'Ontario et le sud-ouest du Québec
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kettles, Inez M. Shilts, William W. |
| Copyright Year | 1994 |
| Abstract | Approximately 2500 samples of till and related sediments have been collected over the Frontenac Arch and adjacent areas of southeastern Ontario and southwestern Q. Although the primary objective of the sampling was to map components in the overburden that might be related to sensitivity of the terrain to the effects of acid rain, the data can be applied also to mineral exploration in the area. The <2 p n fraction of the samples was analyzed for 14 trace and minor elements. Dispersal of these and other mineralogical components can be related to effects ofglacial transport, composition of underlying bedrock, sediment facies sampled, or degree of weathering. Arsenic, for example, is enriched in an area where mining of arsenical gold was carried out in southeastern Ontario. The area of arsenic enrichment ' Commission gbologique du Canada, 601, rue Booth, Ottawa (Ontario) Canada is larger than that underlain by arsenic-bearing bedrock as a result of glacial dispersal of arsenic-rich detritus. Concentrations of copper and chromium, for example, are consistently and uniformly low and high, respectively, in glaciomarine silty clay along the Ottawa and Gatineau valleys, compared to concentrations in the till cover in adjacent highland areas of southwestern Q. The mean concentrations in glaciofluvial and highly weathered till samples are markedly higher than those in unweathered to slightly weathered till. This likely reflects the presence of weathering products with high exchange capacities in the clay-sized fraction of these samples. Carbonate analyses of till demonstrate that the physical nature of source outcrops significantly influences glacial erosion processes. Carbonate minerals derived from horizontal beds of unmetamorphosed Paleozoic limestone northeast of the Frontenac Arch, have been transported southwestward onto the Canadian Shield, effectively diluting the compositional signature of underlying bedrock for over 70 km down-ice from their source areas. In contrast, massive marble outcrops produced very small and weak dispersal trains. -. -. . -. -. -. . . . - |
| File Format | PDF HTM / HTML |
| DOI | 10.4095/194824 |
| Alternate Webpage(s) | http://www.prairie.illinois.edu/shilts/pubs/Kettles_&_Shilts_1994_G%C3%A9ochimie%20des%20s%C3%A9diments%20glaciaires%20dans%20la%20province%20pr%C3%A9cambrienne%20de%20Grenville.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
