| Title | Tagging glacial erosion and till production for drift prospecting |
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| Author | Gosse, J C; Staiger, J W; Fastook, J; Johnson, J; Utting, D; Little, E |
| Source | Geological Society of America 2005 Salt Lake City Annual Meeting; Geological Society of America, Abstracts With Programs vol. 37, no. 7, 4, 2005 p. 398  Open Access |
| Links | Online - En ligne
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| Image |  |
| Year | 2005 |
| Alt Series | Earth Sciences Sector, Contribution Series 2005282 |
| Publisher | Geological Society of America |
| Meeting | Geological Society of America Annual Meeting 2005; Salt Lake City, UT; US; October 16-19, 2005 |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | html; pdf |
| Province | Nunavut |
| Area | Baffin Island |
| Subjects | surficial geology/geomorphology; economic geology; Science and Technology; Nature and Environment |
| Program | Northern Resources Development Program |
| Released | 2005 10 01 |
| Abstract | Among challenges of mineral exploration in glaciated terrain are the characterization of glaciological processes that control till production, transportation, and deposition in regions glaciated by ice
with varying thermal regimes. The basal thermal regime of ice caps and sheets control rates and styles of glacial erosion and therefore till production. In a selected region of northern Baffin Island we classified regions of past cold-based (ice
frozen to substrate) or warm-based (sliding on and within bed) glacier cover based on sedimentology (clast angularity, matrix characteristics), clast provenance (abundance of exotic lithologies), and geomorphology (e.g. lateral meltwater channels).
Tills from 19 sites were analysed for cosmogenic 10Be and 26Al to test the hypothesis that areas of cold-based (less erosive) ice should retain pre-glacial concentrations of the terrestrial in situ cosmogenic nuclides (TCN). In all sites the TCN
concentrations reflected the degree of glacial erosion, with more than two orders of magnitude difference in concentrations between the end-member classes (normalized to sea level and adjusted for small amounts of post-glacial TCN production). A
clear relationship between 26Al/10Be and classified thermal regime support these findings by showing that the cold-based regions experienced pre-glacial exposure interrupted by a long period(s) of burial, presumably by ice, whereas the warm-based
zones had simple exposure histories with no evidence of burial. Three sites had features of both cold-based and warm based conditions, and the TCN concentrations and 26Al/10Be indicate an intermediate history of exposure and shorter burial than pure
cold-based end member sites. UMISM, a finite element thermomechanical ice sheet model predicts the same basal conditions and is used in conjunction with the TCN to help resolve paleo-glacier dynamics and till provenance. The measurement of minimum
ice burial durations of ~3 Myr, suggesting that recently deglaciated surfaces near modern ice caps may have been covered since the Pliocene, is a remarkable account of the impact of the current climate change on Baffin Island ice caps. |
| GEOSCAN ID | 221052 |
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