| Title | Holocene carbonate precipitates on precambrian bedrock in the high arctic: age and potential for palaeoclimatic information |
| |
| Author | Blake, W, Jr |
| Source | Geografiska Annaler, Series A vol. 87, no. 1, 2005 p. 175-192, https://doi.org/10.1111/j.0435-3676.2005.00251.x |
| Image |  |
| Year | 2005 |
| Alt Series | Geological Survey of Canada, Contribution Series 2004118 |
| Alt Series | Cape Herschel Project, Contribution Series 66 |
| Publisher | Informa UK Limited |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Nunavut |
| NTS | 19; 28E; 28F; 28G; 28H; 29; 38E; 38F; 38G; 38H; 39; 48E; 48F; 48G; 48H; 49; 102; 340 |
| Area | Ellesmere Island; Nares Strait |
| Lat/Long WENS | -88.0000 -56.0000 84.0000 74.0000 |
| Subjects | general geology; hydrogeology; surficial geology/geomorphology; stratigraphy; precipitates; carbonates; granites; gneisses; carbon-14 dates; carbon isotopes; carbon ratios; icefields; calcium carbonate;
calcrete; carbonate precipitates; calcareous till; carapace ice caps |
| Illustrations | location maps; tables; photographs; photomicrographs |
| Program | Cape Hershel Project |
| Program | NSERC Natural Sciences and Engineering Research Council of
Canada |
| Released | 2016 11 15 |
| Abstract | Crusts of white carbonate precipitate occur commonly on the upper surfaces of glacially sculptured Precambrian granites and gneisses in east-central Ellesmere Island. Radiocarbon dating of 21 such
carbonate precipitates, from elevations between 50 m and 1050 m a.s.l., has yielded only Holocene ages. Two samples from Ellesmere Island, plus one from Inglefield Land, Greenland, have calibrated ages over 5000 years, the rest are younger. The
formation of these deposits, mainly calcite and characterized by unusually heavy 13C ratios (+3.36 to +15.18 permil), has apparently been aided in some cases by the presence of bacteria, and some crusts seem to have developed where Ca-bearing
minerals are more prevalent. In the case of Bache Peninsula and Cape Herschel, where the carbonate crusts are particularly abundant, the presence of calcareous till may have played a role as well. The carbonate crusts may be related to the presence
of small, thin carapace ice caps, when such features formed at lower elevations than those at which they exist today. The more extensive cover of ice and snow is postulated to have existed during the latter, cooler part of the Holocene, especially
during the period from 2500 to 100 years ago, deduced as a period of low melt from ice core studies on the Agassiz Ice Cap, 200 km to the north. The existence of carapace ice caps at lower elevations also agrees with the radiocarbon evidence for
outlet glacier advances during the last 2000 years on both east and west margins of the Prince of Wales Icefield. Alternatively, the white carbonate crusts may be, to a large degree, the result of weathering processes. In either case they provide
minimum ages for the exposed, ice-sculptured rock surfaces on which they occur. |
| GEOSCAN ID | 215738 |
|
|