Mineralogical, Geochemical and Isotopic Compositions of Fracture Coatings in Athabasca Group Sandstones as Records of Elemental Dispersion
Loading...
Authors
Valentino, Marissa
Date
Type
thesis
Language
eng
Keyword
Dispersion , Uranium , Fractures , Pathfinder Elements , Wall Rock
Alternative Title
Abstract
The McArthur River unconformity-related uranium deposit (~500 m depth) and the deep
Stewardson Lake uranium project (~1100 m depth) are located in the eastern and south-central
sections of the Athabasca Basin. By examining fractures and wall rock from McArthur River and
comparing this analysis with the chemistry from the Stewardson Lake uranium project, this study
determined that fractures can be used to detect dispersion from uranium mineralization at depth.
Petrographic, shortwave infrared reflectance spectroscopic (SWIR) and geochemical studies were
conducted to identify distinct colors, mineral assemblages, and chemical compositions of
fractures. Weak acid leach (WAL) and modified aqua regia (AR) leach analyzed by high-resolution
inductively couple plasma mass spectrometry (HR ICP-MS), indicate that brown
(Type 1) and white and yellow (Type 2) fractures best record evidence of uranium mineralization
at McArthur River through post-mineralization dispersion, as many fractures have low uranium
concentrations and low 207Pb/206Pb values. Brown fractures show elevated concentrations of
pathfinder elements, Co, Ba, Tl, Mn and radiogenic Pb. The 207Pb/206Pb values of fractures and
wall rock reflect post-mineralization dispersion fluids imprinted on wall rock near fractures (low
207Pb/206Pb values; 0.09-0.50), followed by a less radiogenic fluid related to the fracture coatings
(higher 207Pb/206Pb values) at McArthur River and Stewardson Lake. Stable isotope results,
shown by δ18O and δ2H values, indicate that the footprint of the deposit extends upwards by
hydrothermal fluids, through some fractures, including white and yellow fractures rich in fibrous
goethite. Continuous leach (CL)-ICP-MS results show an association between Ni, V, and
radiogenic Pb with Fe oxide and clay minerals during the 30% HNO3 leach phase for these
fracture types.
The mineral chemistry of seven fracture types from McArthur River and five fracture
types from Stewardson Lake indicates that, although multiple fluid events have affected some
fractures, they still preserve evidence of syn-mineralization and post-mineralization dispersion of
elements. The mineralogy and geochemistry of fracture fillings indicate syn- and post-mineralization
mobilization of pathfinder elements from the McArthur River uranium deposit and
Stewardson Lake uranium occurrence at depth, but also provide evidence of a downward
migration of elements from the surface, shown by McArthur River fractures.
Description
Citation
Publisher
License
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.