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TitleHeavy mineral partitioning in sedimentary facies: Lac Baby Esker, Lac Timiskaming region, Canada
AuthorLesemann, J -E; Cummings, D I; Kjarsgaard, B A; Russell, H A J; Sharpe, D R
SourceGeological Survey of Canada, Open File 7425, 2013, 49 pages,
PublisherNatural Resources Canada
Documentopen file
Mediadigital; on-line
File formatpdf; xls
ProvinceOntario; Quebec
NTS31M/05; 31M/06; 31M/11; 31M/12
AreaLake Timiskaming; Lac Baby; Ottawa River; Lac des Quinze; Roulier
Lat/Long WENS-80.0000 -79.1667 47.6667 47.2500
Subjectsgeochemistry; surficial geology/geomorphology; economic geology; esker geochemistry; eskers; kimberlites; pipes; glaciofluvial deposits; sands; boulders; pebble lithology; heavy minerals; heavy mineral analyses; ilmenite; chromite; garnet; clinopyroxene; olivine; diamond; paragenesis; ice transport directions; fluvial transport; mineral exploration; Archean; petrography; Lac Baby Esker; Lake Timiskaming kimberlite field; Cenozoic; Quaternary
Illustrationslocation maps; photographs; tables; flow charts; plots; pie charts; histograms
Natural Resources Canada Library - Ottawa (Earth Sciences)
ProgramMethodological Development, Targeted Geoscience Initiative (TGI-4)
Released2013 08 27 (13:00)
AbstractSampling protocols for heavy minerals (HM) and kimberlite indicator minerals (KIM) in glacifluvial sediments generally follows those established for sampling in fluvial environments. These protocols emphasize sampling of gravely facies. The transfer of this protocol to glacifluvial sediments (especially eskers) assumes that fluvial and glacifluvial systems operate in similar manners. Though they share process similarities, they also have significant differences. Consequently the existing protocol used to sample eskers is largely untested and is not constrained by understanding of glacifluvial processes. In the Lac Baby glacifluvial complex in the Lac Timiskaming region, various esker facies were sampled for KIM in order to assess how these minerals may be partitioned and concentrated in an eskerine depositional environment. The main finding of this study is that gravely esker facies are not necessarily the prime sampling medium in an esker, and that medium to coarse sand facies may be a better choice. However, this does not mean that sampling gravely facies should be abandoned. It is suggested that examining the matrix characteristics of coarser boulder beds is critical, as they may yield KIM. Near
Notre Dame du Nord, heavy mineral (HM) grain counts are elevated within an esker segment where a cobble-boulder bedform occurs. In this bedform, HM grain counts are only slightly lower than the highest HM concentration reported from Lac Baby. Many esker gravely facies record mass flow deposits and poor sorting. These are poor sampling media for KIM due to a lack of density sorting. Nevertheless, other gravel facies have similar KIM concentrations to those reported in medium to coarse sand facies. Consequently, to select the optimum sample medium requires more than simple identification of sedimentary facies, but also the identification of the depositional controls on the facies to optimize sampling strategies based on facies interpretations.
Summary(Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI-4) is a collaborative federal geoscience program that provides industry with the next generation of geoscience knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. A subclass of heavy minerals are commonly sampled to target exploration activities for diamonds. The suite of Kimberlite Indicator Minerals is commonly pyrope garnet, chrome-diopside, olivine, ilmenite, and chromite. Sampling of eskers and intepretation of these indicator minerals is based predominantly on protocols adopted from stream sampling. This study documents the most extensive samping of sedimentary facies and indicator minerals to investigate whether heavy minerals are concentrated preferentially in specific sedimentary facies in eskers.