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TitleUnconformity surface architecture of the northeast Thelon Basin, Nunavut, derived from integration of magnetic source depth estimates
AuthorTschirhart, V; Morris, W A; Jefferson, C W
SourceInterpretation vol. 2, no. 4, 2014 p. SJ117-SJ132,
Alt SeriesEarth Sciences Sector, Contribution Series 20140212
PublisherSociety of Exploration Geophysicists (SEG)
Mediapaper; on-line; digital
File formatpdf
NTS66A; 66B; 66C/01; 66C/02; 66C/03; 66C/06; 66C/07; 66C/08; 66C/09; 66C/10; 66C/11; 66C/14; 66C/15; 66C/16; 66D/01; 66D/02; 66D/03; 66E/01; 66E/02; 66E/03; 66E/04; 66E/05; 66E/06; 66E/07; 66E/08; 66E/09; 66E/10; 66E/11; 66E/12; 66F/01; 66F/02; 66F/03; 66F/04; 66F/05; 66F/06; 66F/07; 66F/08; 66F/09; 66F/10; 66F/11; 66F/12
AreaThelon River; Aberdeen Lake; Schultz Lake
Lat/Long WENS-101.5000 -96.3333 65.7500 64.0833
Subjectsgeophysics; metallic minerals; structural geology; digital terrain modelling; magnetic modelling; modelling, structural; computer mapping; magnetic surveys, airborne; magnetic surveys; uranium; uranium deposits; metasedimentary rocks; hydrothermal alteration; unconformity-type deposit; Thelon Basin
Illustrationslocation maps; magnetic maps; sketch maps; 3-D images; digital images; geophysical images; graphs; structural cross-sections
ProgramSouth Rae Province Bedrock/Surficial geology, GEM2: Geo-mapping for Energy and Minerals
AbstractExploration for unconformity-associated uranium deposits requires detailed 3D knowledge of the depth and morphology of the unconformity surface. Modifications of the unconformity surface by reactivated intersecting faults and favorable basement lithology are key parameters when attempting to vector toward potential deposits. In the absence of seismic reflection and closely spaced drill data, high-resolution aeromagnetic data can provide surprisingly detailed 3D constraints through the use of source depth routines. Such routines are applied to the northeastern part of the Thelon Basin, termed the Aberdeen Subbasin, in Nunavut. This region is considered prospective for unconformity-associated uranium deposits. Deposits have so far been discovered adjacent to the subbasin where they are hosted by structurally complex Neoarchean and early Paleoproterozoic supracrustal rocks. We determined the morphology of two unconformity surfaces by combining the outputs from multiple analyses of high-resolution aeromagnetic data: three semiautomated depth estimation routines (Werner deconvolution, Euler deconvolution, and source parameter imaging) and two potential field inversion procedures. Confidence in depth estimates was increased by combining the output of individual source depth algorithms. Results were integrated with previously mapped fault displacements, seismic refraction profiles, boreholes, and outcrop geology around the subbasin perimeter. An integrated pseudo-3D source depth estimate of the unconformity surface is presented as twenty-three north-south profiles. The revised model of the upper unconformity surface, the base of the Thelon Formation, shows a complex set of stepped blocks bounded by four major intersecting fault arrays with approximate offsets ranging from tens to hundreds of meters.
Summary(Plain Language Summary, not published)
Knowledge of the depth and morphology of the Thelon Basin, Nunavut, is an important parameter for the exploration of unconformity-associated uranium deposits. Exploration tends to focus toward areas with favorable rock units, intersecting faults and minimal sedimentary coverage. This paper presents a 3D model of the northeast Thelon Basin derived from integrating multiple depth algorithms and primary geological constraints. The revised model shows a complex set of stepped blocks bounded by four major intersecting fault arrays with approximate offsets ranging from tens to hundreds of meters.