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TitleLithogeochemical facies of Athabasca Basin clastics, Saskatchewan - the use of PCA as a reconnaissance and mapping tool
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LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorRamaekers, P; Bosman, S A; Card, C D
SourceGeological Survey of Canada, Open File 7790, 2016, 18 pages, https://doi.org/10.4095/297840 Open Access logo Open Access
Year2016
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
File formatreadme
File formatpdf; xlsx; rtf
ProvinceSaskatchewan
NTS64E; 64L; 64M; 74E; 74F; 74G; 74H; 74I; 74J; 74K; 74L; 74M; 74N; 74O; 74P
Areanorthern Saskatchewan
Lat/Long WENS-112.0000 -103.0000 60.0000 57.0000
Subjectsgeochemistry; sedimentology; lithogeochemistry; clastics; clastic facies; geochemical facies; sandstones; tuffs; clays; breccias; quartzarenites; uranium deposits; Athabasca Group; Athabasca Basin; Manitou Falls Formation; Proterozoic
Illustrationslocation maps; tables; plots
ProgramTargeted Geoscience Initiative (TGI-4) Uranium Ore Systems
Released2016 04 07
AbstractThis study illustrates how Principal Component Analysis (PCA) of lithogeochemical data may be used to identify and map lithogeochemical facies using a regional-scale database of ca. 40,000 samples. This database also includes ca. 11,000 samples with enough stratigraphic data to permit this to be done in three dimensions to a rudimentary degree. The facies distribution by stratigraphy and deposystems furthers the understanding of depositional, alteration history, and ore processes of the Athabasca Basin and its high-grade unconformity-related U deposits.
PCA permits distinction and mapping of detrital and alteration facies, separating uraniferous detrital facies from those related to mineralization processes. The analysis helps to form working hypotheses about the ore systems in the basin, identify areas of further interest, as well as areas whose high U values suggest that they might be important, but which, in fact, are not involved in the mineralization processes. Uranium bound in minerals released during partial dissolution techniques contributes less than a third of the U signal in the non-mineralized sandstone. Thus, immobile U not related to alteration can mask the signal of hydrothermal U that still may be recognized by PCA. PCA also highlights potential large, but complex metal depleted zones around some of the major orebodies. If true, then the interpretation of low raw data element values or low U component scores from PCA in a regional context is as important as the interpretation of high values. Samples from above or very near mafic intrusive suites in the basin show anomalously high and low values for some elements, as well as for a number of PCA components. This suggests that the mafic intrusions generated hydrothermal systems of only limited extent.
Consistent with recent fluid-flow modelling, differences in alteration facies above and below the Wolverine Point Formation show that the unit was an aquitard. Low levels of alteration facies in the basal unit in the Athabasca Basin imply that it was an aquifer in many areas. Both these observations reinforce long-standing field observations.
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. Using the Athabasca uranium geochemistry database (OF7495), this open file highlights geochemical variations related to depositional and regional alteration facies in the Athabasca Basin to aid in exploration for unconformity-related uranium deposits.
GEOSCAN ID297840

 
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