GEOSCAN Search Results: Fastlink


TitleHolocene carbonate precipitates on precambrian bedrock in the high arctic: age and potential for palaeoclimatic information
AuthorBlake, W, Jr
SourceGeografiska Annaler, Series A vol. 87, no. 1, 2005 p. 175-192,
Alt SeriesGeological Survey of Canada, Contribution Series 2004118
Alt SeriesCape Herschel Project, Contribution Series 66
PublisherInforma UK Limited
Mediapaper; on-line; digital
File formatpdf
NTS19; 28E; 28F; 28G; 28H; 29; 38E; 38F; 38G; 38H; 39; 48E; 48F; 48G; 48H; 49; 102; 340
AreaEllesmere Island; Nares Strait
Lat/Long WENS -88.0000 -56.0000 84.0000 74.0000
Subjectsgeneral geology; hydrogeology; surficial geology/geomorphology; stratigraphy; precipitates; carbonates; granites; gneisses; carbon-14 dates; carbon isotopes; carbon ratios; icefields; calcium carbonate; calcrete
Illustrationslocation maps; tables; photographs; photomicrographs
ProgramCape Hershel Project
ProgramNSERC Natural Sciences and Engineering Research Council of Canada
Released2016 11 15
AbstractCrusts 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.

Date modified: