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TitlePetrographic and cathodoluminescence characterization of apatite from the Sue-Dianne and Brooke IOCG mineralization systems, Great Bear magmatic zone, Northwest Territories
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AuthorLypaczewski, P; Normandeau, P X; Paquette, J; McMartin, I
SourceGeological Survey of Canada, Open File 7319, 2013, 18 pages, https://doi.org/10.4095/292369 (Open Access)
LinksCanadian Database of Geochemical Surveys, downloadable files
LinksBanque de données de levés géochimiques du Canada, fichiers téléchargeables
Year2013
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
File formatreadme
File formatpdf; rtf; jpeg; tiff
ProvinceNorthwest Territories
NTS85N/15
AreaMazenod Lake; Sarah Lake
Lat/Long WENS-117.0000 -116.5000 64.0000 63.7500
Subjectseconomic geology; mineralogy; petrography; apatite; mineral deposits; mineral occurrences; iron oxides; copper; gold; silver; alteration; igneous rocks; microscopic analysis; scanning electron microscopy; scanning electron microscope analyses; till analyses; Sue-Dianne Deposit; Great Bear magmatic zone; Cathodoluminescence
Illustrationslocation maps; photomicrographs; tables
ProgramIron-oxide Copper-gold (IOCG) / Multiple Metals - Great Bear Lake (NWT), GEM: Geo-mapping for Energy and Minerals
Released2013 03 05
AbstractApatite is the main REE-bearing phase in 19 thin sections from two mineralized systems and their host rocks, the Cu-Ag-(Au) Sue-Dianne IOCG deposit and the nearby Brooke Zone, located within the southern Great Bear magmatic zone, Northwest Territories, Canada. The thin sections show a range of IOCG-related alterations and igneous protoliths. Apatite occurs in all thin sections, in amounts ranging between traces to 5-10%. It can be divided into four populations on the basis of size, cathodoluminescence (CL) response and petrographic association: 1) small euhedral apatite (20-40 µm), occurring in clusters of 5 to 20 grains, generally free of inclusions, found in the volcaniclastic samples; 2) single apatite crystals (60-80 µm) with pitted edges, numerous fluid inclusions and sometimes monazite and hematite inclusions; 3) large single apatite crystals (100-300 µm) within epidote veins, sometimes associated with scheelite; and 4) large fractured apatite crystals (0.5 to 4 mm) with heavy hematite staining associated with hydrothermal breccias. The first 3 populations have a green to yellow CL response and the third population shows some irregular zoning. The fourth population shows a blue CL tint, with irregular green zones throughout grains or near the crystal rims. In that fourth population, mineral inclusions with an orange CL response are likely calcite. Group 3 and 4 also show an heterogeneous REE distribution within crystals under EDX. Given the overprinting of multiple alteration types in many of the specimens, additional work is needed to relate these apatite populations to specific alteration stages associated with IOCG-type mineralization. However, the presence of apatite coarse enough to be picked from glacial sediment samples and showing distinctive CL signatures in rocks related to IOCG mineralization suggests potential as an indicator mineral method.
Summary(Plain Language Summary, not published)
This study examines the physical characteristics of the mineral apatite present in mineralized rocks of iron oxide copper-gold (IOCG) deposits in the western part of the Canadian Shield. This distinctive mineral has the potential to help trace IOCG deposits in the unconsolidated glacial sediments left during the last glaciation in the Great Bear Lake area. This work will help provide the geoscience knowledge required to develop effective mineral exploration methods in formerly glaciated terrain. This work was part an undergraduate research project from McGill University, conducted under the IOCG Great Bear Project at the Geological Survey of Canada, as part of Natural Resources Canada¿s Geo-mapping for Energy and Minerals (GEM) Program.
GEOSCAN ID292369