| Title | Elucidating mineralizing fluid pathways from the geophysical responses to hydrothermal alteration: integrated 3D modelling of lithogeochemical, petrophysical, seismic and magnetotelluric data, Lalor
volcanogenic massive sulphide deposit, Manitoba |
| Download | Download (whole publication) |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Schetselaar, E M ;
Bellefleur, G; Craven, J A; Ansari, S M; Enkin, R J |
| Source | Targeted Geoscience Initiative: 2017 report of activities, volume 1; by Rogers, N (ed.); Geological Survey of Canada, Open File 8358, 2018 p. 229-242, https://doi.org/10.4095/306479  Open Access |
| Year | 2018 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Targeted Geoscience
Initiative: 2017 report of activities, volume 1 |
| File format | pdf |
| Province | Manitoba |
| NTS | 63K/16 |
| Area | Snow Lake |
| Lat/Long WENS | -100.2000 -100.1000 54.9000 54.8500 |
| Subjects | economic geology; geochemistry; geophysics; structural geology; igneous and metamorphic petrology; mineral deposits; mineral exploration; mineral potential; modelling; ore controls; ore mineral genesis;
mineralization; base metals; volcanogenic deposits; sulphide deposits; zinc; hydrothermal systems; hydrothermal alteration; fluid flow; fluid dynamics; lithogeochemistry; geophysical surveys; seismic interpretations; seismic waves; p waves; seismic
reflection surveys; petrophysics; magnetotelluric interpretations; conductivity; electromagnetic fields; whole rock geochemistry; statistical analyses; regression analyses; drill core analyses; bedrock geology; lithology; igneous rocks; intrusive
rocks; mafic intrusive rocks; gabbros; diorites; granodiorites; tonalites; granites; ultramafic rocks; volcanic rocks; volcaniclastics; tuffs; rhyolites; dacites; lava flows; breccias; basalts; andesites; rhyodacites; structural features; faults;
faults, thrust; Archean; Canadian Shiield; Trans-Hudson Orogeny; Chisel Basin; Lalor VMS deposit; Sask Craton; Chisel- Lalor structural contact; Precambrian; Proterozoic |
| Illustrations | geoscientific sketch maps; plots; 3-D images; tables; 3-D models; models; cross-sections; graphs |
| Program | Targeted Geoscience Initiative (TGI-5) Knowledge Management Coordination |
| Program | Targeted Geoscience Initiative (TGI-5) Volcanic and sedimentary systems |
| Released | 2018 01 19 |
| Abstract | This research activity aims a developing a better understanding of the geophysical response of hydrothermally-altered rocks associated with volcanogenic massive sulphide (VMS) deposits. Integrated
modelling of physical rock property, whole rock geochemistry and 3D seismic data from the Lalor VMS deposit, Snow Lake, Manitoba enhanced insight into the seismic responses of hydrothermally-altered rocks in the footwall of the massive sulphide ore
zone. Multivariate regression of P-wave velocity and density on lithogeochemical proxies for protolith composition, mineralization and hydrothermal alteration suggests that hydrothermal alteration in the footwall of the Lalor deposit enhanced
acoustic impedance contrast between mafic to felsic volcanic units. Compositional variations between mafic, intermediate and felsic volcanic rocks, as modelled by the log(Zr/TiO2) immobile element ratio, remains the predominant factor that controls
seismic response, independent from the intensity of hydrothermal alteration. The results obtained from the multivariate regression model are further corroborated by seismic forward modelling experiments, yielding enhanced seismic reflectivity in the
intensely-altered footwall when alteration proxies are included in the 3D seismic rock property models. In parallel, geophysical response modelling of magnetotelluric (MT) data will be developed based on forward and inverse modelling routines on
tetrahedral meshes, which yield results that are compatible with the general geological structure of the deposit. Initial unconstrained 3D MT inversions show a conductive zone between 600 to 800 m depth corresponding to the Lalor deposit, as well as,
a highly conductive zone between depths of 500 to 1500 m, about 0.5 to 1.2 km to the southwest of the deposit. |
| Summary | (Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI) is directed towards providing next generation knowledge and methods to facilitate more effective targeting of
buried mineral deposits. The program aims to enhance the effectiveness of exploration for Canada¿s major mineral systems by resolving foundational geoscience problems that constrain the geological processes responsible for the liberation metals from
their source region, transportation of these ore metals and control their eventual deposition. TGI supports projects on gold, Ni-Cr-PGE, porphyry-style mineralization, uranium and volcanic- and sedimentary-hosted base metal mineralization ore
systems, with each project divided into subprojects focused on resolving specific knowledge gaps by integrating data and studies from multiple sites across Canada. Herein, we present interim results and interpretations from a selection of the
research activities currently being conducted under the auspices of TGI. |
| GEOSCAN ID | 306479 |
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