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TitreKimberlite indicator minerals and gold grains in till from the Great Bear magmatic zone and Wopmay metamorphic zone, Northwest Territories, Canada
AuteurNormandeau, P X; McMartin, I; Jackson, V; Corriveau, L; Paquette, J
SourceNorthwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume 2014, 2014 p. 97
Année2014
Séries alt.Secteur des sciences de la Terre, Contribution externe 20140291
ÉditeurNorthwest Territories Geoscience Office
Réunion42nd Annual Yellowknife Geoscience Forum; Yellowknife; CA; Novembre 25-27, 2014
Documentpublication en série
Lang.anglais
Mediaen ligne; numérique
Formatspdf
ProvinceTerritoires du Nord-Ouest
SNRC86
Lat/Long OENS-120.0000 -112.0000 67.0000 64.0000
Sujetskimberlites; éléments d'indice; gisements minéraux; gîtes minéralogiques; or; minéralisation; tills; analyses de till; géologie économique; géologie des dépôts meubles/géomorphologie
ProgrammeÉtude des gîtes d'uranium, Initiative géoscientifique ciblée (IGC-4)
LiensOnline - En ligne (p.97)
Résumé(disponible en anglais seulement)
Kimberlite indicator minerals (KIM) and gold grain counts from near surface till samples were collected as part of an applied Quaternary activity within the IOCG-Great Bear Multiple Metals GEM project in partnership with the South Wopmay Bedrock Mapping Project & Integrated Studies. Till sampling sites were designed primarily for an IOCG study focused on the Sue Dianne Cu-Ag-Au magnetite to hematite-group IOCG deposit (n=30), the Fab Lake U-Th-Cu magnetite-group IOCG showings (n=23) and the Au?Co?Bi?Cu NICO magnetite-group IOCG deposit (n=13) in the south GBmz but include 39 samples collected across the Great Bear magmatic zone (GBmz) and extending into the Wopmay metamorphic zone and Slave Craton.
Heavy mineral separation (S.G. >3.2) and indicator mineral picking was performed by Overburden Drilling Management Ltd. Potential KIM species identified include; Cr-pyrope garnet, chromite, Mg-rich olivine and Cr-rich diopside. All reported values are normalized to a 10 kg sample using the table feed value. The most common species is Cr-pyrope garnet found in 41 samples within the 0.25 to 0.5 mm fraction and in 4 samples within the 0.5 to 1 mm fraction. One Cr-pyrope garnet is present within the >1 mm fraction. Mg-Olivine, Cr-diopside and chromite grains are respectively found in 15, 11 and 8 samples within the 0.25 to 0.5 mm fraction and are rarely present within the 0.5 to 1 mm fraction. The maximum number of grains found in a single sample is 5.1 grains/10kg but 18 samples contain 2 grains/10 kg or more. Samples from the south GBmz are commonly enriched in potential KIM but high grain counts are also present throughout the study area.
The total visible gold grain counts vary from none to 34.6 grains/10kg with an average of 2.9. Modified gold grain counts reach a maximum of 12.3 grains/10kg with an average of 0.6. Reshaped gold grain counts reach a maximum of 14 grains/10kg with an average of 2. Eleven samples contain pristine gold grains (1 to 11.2 grains/10 kg), and these samples all have high contents of modified and reworked gold grains as well. While pristine and modified gold grains are rare, reshaped gold grain contents correlate well with known IOCG systems of the GBmz such as the NICO and Sue Dianne deposits and to some extent, the Fab Lake system in a context of short transport distances. This suggests that the reshaping of gold grains took place either rapidly during glacial transport or in situ caused by wave action from Glacial Lake McConnell. In either case, reshaping of the grains should not be used as an argument to support large transport distances and/or necessarily associating these grains with background values.
Résumé(Résumé en langage clair et simple, non publié)
L¿Initiative géoscientifique ciblée (IGC-4) est un programme géoscientifique fédéral de collaboration qui fournit à l¿industrie les connaissances géoscientifiques et les techniques novatrices de prochaine génération dont elle a besoin pour mieux détecter les gîtes minéraux enfouis, réduisant ainsi certains risques liés à l¿exploration.Cette affiche présente les résultats et les interprétations de comptages de minéraux indicateurs de kimberlite et de grains d¿or échantillonnés des sédiments glaciaires non consolidés laissés au cours de la dernière glaciation dans la région du Grand Lac de l'Ours. Ces travaux aideront à fournir les connaissances géoscientifiques nécessaires pour développer des méthodes d'exploration minérale efficaces en terrain anciennement englacés. Les échantillons ont été recueillis dans le cadre du Programme en géocartographie de l'énergie et des minéraux (GEM-1) et la recherche se poursuit sous l¿Initiative Géoscientifique Ciblée 4.
GEOSCAN ID295505