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 Proactive disclosure Print version   | |  EXTECH IV: Athabasca Uranium multidisciplinary study
The Context of Unconformity-type Uranium Deposits in the Paleoproterozoic Athabasca Basin
Table of Contents
Project Description: EXTECH IV aims to enhance the 4-dimensional geoscience knowledge base of the 1.7 billion year-old Athabasca Basin and to develop new exploration methods for deep uranium deposits that are located at or near its basal unconformity with basement gneisses, thereby sustaining and enhancing the environmentally sound development of this mature mining camp. Integrated, multiparameter geophysical - geological studies focus on a high-resolution seismic reflection survey that transects the world's largest super-high grade uranium deposit at McArthur River. Linked borehole geophysical, organic geochemical, stratigraphic, basement structural, airborne and ground geophysical, clay mineralogical and Quaternary studies span the basin. Strategic impacts of these eight sub-projects are enhanced by guidance from an industry-chaired steering committee, student training, workshops, industry financial and logistical support, active participation and two-way technology transfer with industry, archiving substantial data sets and publication of results. The structural-stratigraphic framework provided by EXTECH IV is critical to the success of a parallel initiative: "A Coupled Mechanical-Heat Flow-Fluid Flow-Geochemical Modeling Investigation of the Eastern Athabasca Unconformity-Type Uranium Deposits" that is partnered by CSIRO (Commonwealth Scientific Industry Research Organization), SRC (Saskatchewan Research Council), Anglo Gold Ltd., Cameco Corporation and COGEMA Resources Inc. EXTECH IV is helping to sustain Canada's world leadership in uranium production, support northern employment, develop and transfer new exploration technology. Relevance is ensured by a close partnership among GSC, SEM (Saskatchewan Energy and Mines), AGS (Alberta Geological Survey), Cameco, COGEMA, and the universities of Regina, Saskatchewan and Laurentian. Application of the ESS-NSERC-Industry Partnership program is enhancing scientific relevance and the training of young Canadian scientists. 2003: Overview and Impact Key Words: Late Paleoproterozoic, northern Saskatchewan-Alberta, Athabasca Sandstone, organic matter, Taltson-Rae-Hearne gneiss, K-U anomalies, seismic reflection, magnetotelluric, gravity, multi-parameter borehole geophysics, unconformity-associated uranium, EXploration TECHnology
Index Maps
Fifteen sub-projects have evolved within the three-year EXTECH IV partnership project, from data acquisition through interpretation to integration, addressing two goals: A) improve Athabasca Basin geoscience knowledge in both well explored and frontier areas and B) enhance and develop EXploration TECHnology to image the geology of, and detect alteration vectors toward world class orebodies such as at McArthur River and Cigar - Cluff - Key - McClean - Rabbit lakes. Models for unconformity-associated uranium deposits were evaluated and extended by addressing these goals. Desired outcomes are to :
Management of EXTECH IV is by a Steering Committee (sub-project 8) comprising senior representatives of the five core funding partners: Natural Resources Canada, Alberta Geological Survey, Saskatchewan Industry and Resources, Cameco Corp. and COGEMA Resources Inc. Additional partnerships with the National Science and Engineering Research Council (NSERC) support research at the universities of Alberta, Regina, Saskatchewan and Laurentian. In-kind contributions and expertise from Saskatchewan Research Council, Geomatics Canada (NRCan), Geosystem Canada and MF Resources Inc. have significantly enhanced the project. The components of EXTECH IV are listed in Table 1 and their locations shown in Figures 1 and 2. Table 1. EXTECH IV sub-projects and research teams. Locations shown in Figure 2.
Impacts of EXTECH IV are already being felt, although the full impact of geoscience research is generally measured over periods of decades. In total, some $7.5 million have been allocated by partners over 3 years to acquire and deliver data with preliminary interpretations. Partners have stated that EXTECH IV has generated new staking of most of the Alberta portion of Athabasca Basin, developed new ideas, resolved old questions, increased confidence and quality of models affecting exploration and land-management decisions, trained 10 young scientists, and has demonstrated a number of new or enhanced exploration technologies that are being adopted in the Basin. These results favour northern and aboriginal employment and sustainable development. Jefferson et al. (2003a, b, c) summarize progress and refer to substantive reports from each sub-project in Saskatchewan Industry and Resources Summary of Investigations. These reports are supplemented by a web site, conference presentations and publication in Geological Survey of Canada, Alberta Geological Survey and journal media. A synthesis year is proposed to complete publication of a peer reviewed comprehensive volume and to identify future research priorities. Scientific highlights are here presented thematically as they address critical exploration and framework parameters of the Athabasca Basin and its contained uranium deposits (Fig. 3). Regional to detailed framework sub-projects (1,3,4,4a,5,5a,6a,7,11) document, put into spatial and temporal context, and interpret key exploration parameters. EXploration TECHnology sub-projects (1,2,6,9,10) calibrate, detect, image and extrapolate physical properties and exploration vectors that include: basement conductors, faults, the basal unconformity, mineralogical alteration, paleovalleys, hydrocarbons, fluid flow tracers, and the ore itself. Numbers in parentheses link the following results to the products of specific sub-project teams that are cited in Jefferson et al. (2003). Regional framework studies of basement to the Athabasca Basin (5,11) have resolved map-boundary faults between Saskatchewan and Alberta, simplified basement domains, demonstrated continuity of the Taltson-Thelon magmatic event southeast under the southwestern part of the basin, documented Archean through Proterozoic ages and polarities of faults such as the Snowbird Tectonic Zone (5), P2 Fault (1,4a) and the Sue Trend (5a). Detailed basement studies (5a) have documented the late brittle reactivation and predictive geometric relationships of basement faults to structural lenses of high-grade uranium ore. Pre-EXTECH mineralogical research (Wasyliuk) has been extended, used to calibrate a new portable spectral device and integrated with borehole geophysics (2,7). Regional to detailed stratigraphic studies (4, 4a) have developed quantitative systematic descriptive parameters that fortify pioneering work by Ramaekers, establish regional and detailed stratigraphic elements and exploration frameworks, and interpret the tectonic and depositional evolution of the Athabasca Basin. New standards were developed for uraninite dating by ion microprobe, and detrital zircon geochronology has both characterized deposystems and established new maximum ages for formations, such as 1.66 Ga for the Wolverine Point Formation (11). Changes in depositional systems and subsidence rates and polarities through time can be linked to ongoing periodic reactivation of brittle fault zones that are spatially associated with uranium mineralization processes. Paleo-valleys, documented by local sedimentary thickness / facies changes and paleocurrents (4a), are spatially associated with growth faults and ore deposits (5a). Proterozoic hydrocarbons have been distinguished from Phanerozoic hydrocarbons and both have been tracked throughout the Basin (3). Organic petrography demonstrates post-ore timing of locally associated bitumens, paleo-temperatures recording focused heat flow in late faults (3) and in accord with clay mineralogy, peak diagenesis temperatures from 190° to 230° C at the unconformity (3, 7).
EXploration TECHnology sub-projects have tracked the ductile fault zones deep into the crust (1), imaged a widespread bright reflector that may represent a major mafic sill (1), demonstrated the wide effects of brittle reactivation of faults on rock properties (1,2,9,10), developed models showing the development of basement highs through syn-to-post-Athabaca Group tectonics (1), imaged silicification, de-silicification, clay alteration and extensive fracture systems (1,2,7,9,10), continuously tracked a zone of impedance contrast that more or less represents the basement-sandstone unconformity (1), and detected new deep conductors (9) as well as demonstrating better tools to detect conductors and alteration in frontier areas (2,9). The combined energy and enthusiasm of the more than 80 scientists and managers from all partners in this project have achieved remarkable results in just 3 years. Moral support and funding by managers of government organizations including NSERC has been strong and sustained, and allowed us to involve young scientists who in turn have done some of the best work. In-kind expertise and guidance combined with logistical and cash support from Cameco and COGEMA from inception to the present have been outstanding. This synopsis was written by the Steering Committee. Critical reviews by Paul Ramaekers, Reg Olson and Jeanne Percival improved earlier versions of this synopsis. This synopsis is based on, and points to, the substantive work of each sub-project team whose members are listed in Table 1, and whose individual project descriptions and products are linked here. 2002-2003 Activities and Results 
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