| Title | Bottom-up mineral exploration: ore-element upgrading in the upper mantle and tools for its discovery |
| Download | Downloads |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Lawley, C J M ;
Kjarsgaard, B A |
| Source | Targeted Geoscience Initiative 5: contributions to the understanding of Canadian gold systems; by Mercier-Langevin, P (ed.); Lawley, C J M (ed.); Castonguay, S (ed.); Geological Survey of Canada, Open File 8712, 2020 p. 157-164, https://doi.org/10.4095/323674  Open Access |
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| Year | 2020 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Targeted Geoscience
Initiative 5: contributions to the understanding of Canadian gold systems |
| File format | pdf |
| Province | British Columbia; Ontario; Nunavut |
| NTS | 32D/04; 32D/05; 76E; 104N |
| Area | Atlin; Kirkland Lake; Contwoyto Lake |
| Lat/Long WENS | -134.0000 -132.0000 60.0000 59.0000 |
| Lat/Long WENS | -79.7500 -79.7500 48.4833 48.1167 |
| Lat/Long WENS | -112.0000 -110.0000 66.0000 65.0000 |
| Subjects | economic geology; tectonics; igneous and metamorphic petrology; geochemistry; geophysics; Science and Technology; Nature and Environment; mineral deposits; gold; diamond; mineral exploration;
exploration methods; ore mineral genesis; mineralization; ore controls; mantle; crustal studies; tectonic setting; lithosphere; oceanic crust; ophiolites; continental crust; craton; subduction zones; downgoing slab; source areas; bedrock geology;
lithology; igneous rocks; intrusive rocks; kimberlites; peridotites; harzburgites; pyroxenites; lherzolites; transport mechanisms; sulphides; base metals; precipitation; fluid inclusions; metasomatism; mineral enrichment; geochemical analyses; whole
rock geochemistry; trace element geochemistry; isotopic studies; mass spectrometer analysis; geophysical surveys; geophysical interpretations; electron microscope analyses; Canadian Cordillera; Nahlin Ophiolite; Canadian Shield; Superior Craton;
Slave Craton; Data processing; Phanerozoic; Precambrian |
| Illustrations | location maps; schematic cross-sections; photomicrographs; geochemical plots |
| Program | Targeted Geoscience Initiative (TGI-5) Gold ore systems |
| Released | 2020 06 11; 2023 03 17 |
| Abstract | Mineral exploration targeting typically focuses on the critical pathways and depositional traps of ore systems. The role of pre-enriched source regions on ore deposit genesis is unclear, particularly
for systems that involve significant transport of ore components (e.g. Au). Because Au is suggested to be derived from the mid- to lower-crust and/or upper mantle at orogenic deposits, it is not surprising that the deepest and most inaccessible parts
of this ore system is also the least studied and understood. Herein we address that knowledge gap by studying the upper mantle directly, using examples of young ophiolitic mantle (Atlin, British Columbia) and ancient cratonic mantle (Superior craton,
Ontario; Slave craton, Nunavut). Project results demonstrate two dominant mechanisms for Au upgrading in the lithospheric mantle: (1) base metal sulphide precipitated during melt:rock reactions between peridotitic residues and asthenospheric melts,
and (2) hydrous, fluid-inclusions trapped after release from subducting slabs. The remelting of such pre-enriched metasomatized mantle has been previously proposed as a viable source for a variety of ore systems (e.g. mafic to ultramafic rock-hosted
platinum-group element deposits). Mapping the architecture of these deep lithospheric metasomatized mantle domains and their association with rising asthenospheric melts is of significant interest for mineral exploration. New geochemical methods and
data processing completed as part of the current study, coupled with advances in geophysical imaging, provide additional tools for mapping these pre-enriched lithospheric mantle domains at depth. |
| Summary | (Plain Language Summary, not published)
The main objective of phase 5 (2015-2020) of Natural Resources Canada and Geological Survey of Canada's Targeted Geoscientific Initiative (TGI) program
was to generate new knowledge, methodologies and models to enhance the exploration industry's ability to detect buried ore deposits. This synthesis volume contains 20 individual papers that discuss craton to deposit-scale characteristics of
auriferous deposits, plus some support material pertaining to the TGI-5 Gold project. |
| GEOSCAN ID | 323674 |
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