Characteristics and Origin of Calcretes in a Subarctic Environment, Great Kobuk Sand Dunes, Northwestern Alaska, U.S.A

Carbonate cementation of dune sand forms under subarctic, almost semiarid conditions in an active dune field in the Kobuk Valley, northwestern Alaska. Calcretes are cemented by low-magnesium calcite derived from carbonate grains incorporated within the dune sands. Two types of calcrete can be distin...

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Bibliographic Details
Published inArctic and alpine research Vol. 18; no. 4; pp. 377 - 387
Main Authors Jos W. A. Dijkmans, Koster, Eduard A., Galloway, John P., Mook, Willem G.
Format Journal Article
LanguageEnglish
Published Institute of Arctic and Alpine Research 01.11.1986
Subjects
Carbonates
Dune sand
Dunes
Geology
Permafrost
Precipitation
Quartz
Sand dunes
Sea water
Surface water
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Summary:Carbonate cementation of dune sand forms under subarctic, almost semiarid conditions in an active dune field in the Kobuk Valley, northwestern Alaska. Calcretes are cemented by low-magnesium calcite derived from carbonate grains incorporated within the dune sands. Two types of calcrete can be distinguished. The first type, in which initial calcrete formation has been observed, lies a few decimeters below the surface in interdune areas. The second type comprises remnants of calcretes of early Holocene age, which occur extensively in various interdune areas and in a large deflation area and are presently being redistributed by frost action. These calcretes were buried by westerly migrating dunes and subsequently exhumed by deflation. Radiocarbon dates of the calcretes (approximately 10,000 yr BP) provide a minimum age for the dune formation. Stable-isotope analysis of the calcretes indicates precipitation of carbonate mainly due to a loss of CO2in the groundwater without significant evaporation, a process favored by cold climates.
ISSN:0004-0851
2325-5153
DOI:10.2307/1551087