Structural evolution and related implications for uranium mineralization in the Patterson Lake corridor, southwestern Athabasca Basin, Saskatchewan, Canada
{"title":"Structural evolution and related implications for uranium mineralization in the Patterson Lake corridor, southwestern Athabasca Basin, Saskatchewan, Canada","authors":"D. Johnstone, K. Bethune, C. Card, V. Tschirhart","doi":"10.1144/geochem2020-030","DOIUrl":null,"url":null,"abstract":"The Patterson Lake corridor is situated along the SW margin of the Athabasca Basin and contains several basement-hosted uranium deposits and prospects. Drill core investigations during this study have determined that granite, granodiorite, mafic and alkali intrusive basement rocks are entrained in a deep-seated NE-striking subvertical heterogeneous high-strain zone defined by anastomosing ductile to semi-brittle shears and brittle faults. The earliest phases of ductile deformation (D1/D2), linked with Taltson (1.94–1.92 Ga) orogenesis, involved interference between early fold sets (F1/F2) and development of an associated ductile transposition foliation (S1/S2). During subsequent Snowbird (c. 1.91–1.90 Ga) tectonism, this composite foliation was re-folded (D3) by NE-trending buckle-style folds (F3), including a regional fold centred on the Clearwater aeromagnetic high. In continuum with D3, a network of dextral-reverse chloritic-graphitic shears, with C–S geometry, formed initially (D4a) and progressed to more discrete, spaced semi-brittle structures (D4b; c. 1.900–1.819 Ga). Basin development (D5a; <c. 1.819 Ga) was marked by a set of north-striking normal faults and related east- and NE-striking transfer faults that accommodated subsidence. Primary uranium mineralization (D5b; c. 1.45 Ga) was facilitated by brittle reactivation of NE-striking basement shears in response to WSW–ENE-directed compressional stress (σ1). Uraninite was emplaced along σ1-parallel extension fractures and dilational zones formed at linkages between NE- and ENE-striking dextral strike-slip faults. Uranium remobilization (D5c) occurred after σ1 shifted to WNW–ESE, giving rise to regional east- and SE-striking conjugate faults, along which mafic dykes (1.27 and 1.16 Ga) intruded. Thematic collection: This article is part of the Uranium Fluid Pathways collection available at: https://www.lyellcollection.org/cc/uranium-fluid-pathways","PeriodicalId":55114,"journal":{"name":"Geochemistry-Exploration Environment Analysis","volume":"21 1","pages":""},"PeriodicalIF":1.0000,"publicationDate":"2020-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"9","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geochemistry-Exploration Environment Analysis","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1144/geochem2020-030","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 9
Abstract
The Patterson Lake corridor is situated along the SW margin of the Athabasca Basin and contains several basement-hosted uranium deposits and prospects. Drill core investigations during this study have determined that granite, granodiorite, mafic and alkali intrusive basement rocks are entrained in a deep-seated NE-striking subvertical heterogeneous high-strain zone defined by anastomosing ductile to semi-brittle shears and brittle faults. The earliest phases of ductile deformation (D1/D2), linked with Taltson (1.94–1.92 Ga) orogenesis, involved interference between early fold sets (F1/F2) and development of an associated ductile transposition foliation (S1/S2). During subsequent Snowbird (c. 1.91–1.90 Ga) tectonism, this composite foliation was re-folded (D3) by NE-trending buckle-style folds (F3), including a regional fold centred on the Clearwater aeromagnetic high. In continuum with D3, a network of dextral-reverse chloritic-graphitic shears, with C–S geometry, formed initially (D4a) and progressed to more discrete, spaced semi-brittle structures (D4b; c. 1.900–1.819 Ga). Basin development (D5a;
期刊介绍：
Geochemistry: Exploration, Environment, Analysis (GEEA) is a co-owned journal of the Geological Society of London and the Association of Applied Geochemists (AAG).
GEEA focuses on mineral exploration using geochemistry; related fields also covered include geoanalysis, the development of methods and techniques used to analyse geochemical materials such as rocks, soils, sediments, waters and vegetation, and environmental issues associated with mining and source apportionment.
GEEA is well-known for its thematic sets on hot topics and regularly publishes papers from the biennial International Applied Geochemistry Symposium (IAGS).
Papers that seek to integrate geological, geochemical and geophysical methods of exploration are particularly welcome, as are those that concern geochemical mapping and those that comprise case histories. Given the many links between exploration and environmental geochemistry, the journal encourages the exchange of concepts and data; in particular, to differentiate various sources of elements.
GEEA publishes research articles; discussion papers; book reviews; editorial content and thematic sets.
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