|Title||Till and bedrock heavy mineral signatures of the Kiggavik uranium deposits, Nunavut|
|Author||Robinson, S V J; Jefferson, C W; Paulen, R C; Layton-Matthews, D; Joy, B; Quirt, D|
|Source||Geological Survey of Canada, Open File 7771, 2016, 70 pages, https://doi.org/10.4095/297563 (Open Access)|
|Publisher||Natural Resources Canada|
|File format||rtf; pdf; xlsx|
|Lat/Long WENS||-97.7500 -97.5000 64.5000 64.3333|
|Subjects||surficial geology/geomorphology; economic geology; geochemistry; igneous and metamorphic petrology; glacial deposits; tills; till geochemistry; till deposits; indicator elements; drift prospecting;
dispersal patterns; sediment dispersal; mineralization; exploration methods; ice flow; uranium; bedrock geology; heavy minerals; heavy minerals geochemistry; heavy mineral analyses; petrography; scanning electron microscopy; electron microscope
analyses; Kiggavik uranium deposit; Baker Lake Group; Wharton Group; Dubawnt Supergroup; indicator minerals; Cenozoic; Quaternary|
|Illustrations||location maps; tables; flow charts; photographs; photomicrographs|
|Program||Hudson/Ungava, Northeastern Quebec-Labrador, surficial geology, GEM2: Geo-mapping for Energy and Minerals|
|Released||2016 01 28|
|Abstract||In 2010, a drift prospecting study was initiated over the Kiggavik uranium (U) deposit under the Geomapping for Energy and Minerals (GEM) Program. The objective of this study was to document the till
geochemical and heavy mineral signatures of the Kiggavik U deposit and to identify potential applications of those characteristics in future exploration for drift-covered, basement-hosted, unconformity-related U deposits. The study area is within the
zone affected by the migration of the Keewatin Ice Divide of the Laurentide Ice Sheet. Mineralized and non-mineralized bedrock and near-surface till samples (n = 71) were collected directly overlying, up-ice, and at various distances (50 m, 100 m,
200 m, 500 m, 1 km, 2 km, 3 km, 5 km, and 10 km) in a fan-shaped pattern down-ice from the deposit with respect to the dominant north-northwest, northwest, and west ice-flow directions. |
Detailed microscopy and microprobe analysis of ore samples
from drill core reaffirmed uraninite and coffinite as the dominant ore minerals at the Kiggavik U deposit, with accessory galena, pyrite and very minor native gold associations. These minerals are predominantly very fine-grained and rarely exceed 100
?m in diameter, with the exception of rare massive crystalline uraninite.
Examination of the sand-size heavy mineral concentrate (HMC) from till yielded no U-rich or directly associated accessory ore minerals, reflecting the overall fine-grained
nature and instability of these minerals in oxidizing conditions such as those found in near-surface till. This ultimately limits the utility of these minerals as empirical indicators of U deposits.
Native gold grains in till samples collected in
this study are, however, more abundant than those in regional background samples. Elevated counts were found up to 3 km down-ice of the Kiggavik Main Zone (KMZ) in a west-northwest direction. The sample containing the highest gold grain count in till
was collected directly overlying the KMZ, suggesting local provenance and the applicability of native gold as an indicator mineral for Kiggavik-style unconformity-type U deposits. Moreover, Pb-rich fluorapatite grains (up to 8% PbO), from the
alteration zone around the KMZ U deposit, are of particular interest due to their uniqueness, stability under near-surface weathering conditions, and thus their potential to be an indicator mineral for such deposits. However the fluorapatite grains
are very finely crystalline, as are the main Ubearing phases observed in ore samples, therefore a new technique to separate, collect, and identify the finer fraction of the HMC needs to be developed.
|Summary||(Plain Language Summary, not published)|
In 2010, a drift prospecting study was initiated over the Kiggavik uranium deposit under the Geomapping for Energy and Minerals (GEM) Program. The
objective of this study was to document the till geochemical and heavy mineral signatures of the Kiggavik uranium deposit and to apply these geochemical characteristics for future exploration for buried, drift-covered uranium deposits. The study area
is within the zone affected by the migration of the Keewatin Ice Divide of the Laurentide Ice Sheet. Mineralized and non-mineralized bedrock and surface till samples(n=71) were collected directly overlying, up-ice, and at various distances (50 m, 100
m, 200 m, 500 m, 1km, 2 km, 3 km, 5 km, and 10 km) in a fan-shaped pattern down-ice from the deposit with respect to the dominant north-northwest, northwest, and west ice-flow directions. This open file contains the detailed microscopy and microprobe
analysis of bedrock samples and heavy minerals picked from till samples.