| Title | Data-driven prospectivity modelling of sediment-hosted Zn-Pb mineral systems and their critical raw materials |
| |
| Author | Lawley, C J M ;
McCafferty, A E; Graham, G E; Gadd, M G; Huston, D L; Kelley, K
D; Emsbo, P; Czarnota, K; Paradis, S; Peter, J M; Hayward, N; Barlow, M; Coyan, J; San Juan, C |
| Source | Ore Geology Reviews vol. 141, 104635, 2021 p. 1-23, https://doi.org/10.1016/j.oregeorev.2021.104635  Open Access |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20210482 |
| Publisher | Elsevier |
| Document | serial |
| Lang. | English |
| Media | on-line; digital |
| File format | pdf |
| Province | Canada; British Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut |
| NTS | 1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65;
66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560 |
| Area | Canada; United States of America; Australia |
| Lat/Long WENS | -120.0000 -70.0000 50.0000 15.0000 |
| Lat/Long WENS | 110.0000 150.0000 -10.0000 -40.0000 |
| Lat/Long WENS | -141.0000 -50.0000 90.0000 41.7500 |
| Subjects | environmental geology; mineralogy; Science and Technology; modelling, structural; modelling; zinc; lead; minerals; machine learning |
| Illustrations | schematic diagrams; tables; photomicrographs; location maps; geological sketch maps; bar graphs; plots |
| Program | Targeted Geoscience Initiative (TGI-6) Digital Geoscience and Method Development Project |
| Released | 2021 12 09 |
| Abstract | Demand for critical raw materials is expected to accelerate over the next few decades due to continued population growth and the shifting consumption patterns of the global economy. Sedimentary basins
are important sources for critical raw materials and new discoveries of sediment-hosted Mississippi Valley-type (MVT) and/or clastic-dominated (CD) deposits are likely required to mitigate future supply chain disruptions for Zn, Pb, Ag, Cd, Ga, Ge,
Sb, and In. However, the drivers, sources, pathways, and traps of MVT and CD deposits and their mappable proxies within the much larger, variably covered, and mostly unmineralized sedimentary basins remain some of the least understood aspects of
these mineral systems. Herein we address those knowledge gaps by integrating public geoscience datasets from Canada, the United States of America, and Australia using a discrete global grid system to map the continent scale footprints of MVT and CD
deposits. Statistical analysis of the model results demonstrate that surface wave tomography and derivative products from satellite gravity datasets can be used to map the most favourable paleo tectonic settings of MVT and CD deposits inboard of
orogenic belts and at the rifted edges of cratonic lithosphere, respectively. Basin development at pre existing crustal boundaries was likely important for maintaining the low geothermal gradients that are favourable for metal transport and
generating the deep fluid-pathways that were re-activated during ore-formation, as suggested by the statistical association between both sediment hosted mineral systems with the edges of upward-continued gravity and long wavelength magnetic
anomalies. We further demonstrate that maximum and minimum geological ages, coupled with Phanerozoic paleo-geographic reconstructions, represent mappable proxies for the availability of oxidized, brine-generating regions that are the most likely
source of ore-forming fluids (e.g., low- to mid-latitude carbonate platforms and evaporites). Deposition of Zn, Pb, and associated critical raw materials was likely controlled by interaction between oxidized, low-temperature brines and sulphidic
and/or carbonaceous rocks, which, in some cases, can be mapped at surface or matched with the available rock descriptions. Baseline weights of evidence models are based on regional geophysics and are the least impacted by the availability of surface
exposure, but yield relatively poor performance, as demonstrated by the low area under the curve (AUC) for the spatially independent test set on the success-rate plot (AUC = 0.643 and AUC = 0.588 for MVT and CD, respectively). Model performance can
be improved by: (1) using advanced methods that were trained and validated during a series of semi automated machine learning compositions; and (2) incorporating geological and geophysical datasets that address each component of the mineral system.
The best-performing gradient boosting machines models from these competitions yield an AUC of 0.954 and 0.933 for MVT and CD deposits, respectively, for the same test set. These preferred prospectivity models reduce the search space for 90% of MVT
and CD deposits by >96%. Overall, model results highlight the potential benefits of mapping sediment-hosted mineral systems at the largest spatial scales to improve mineral exploration targeting for critical raw materials. |
| Summary | (Plain Language Summary, not published)
The current study was completed as part of the Critical Mineral Mapping Initiative (CMMI) between the Geological Survey of Canada (GSC), the United
States Geological Survey (USGS), and Geoscience Australia (GA). We report prospectivity model results for sediment-hosted mineral deposits to support mineral exploration for critical raw materials in sedimentary basins. |
| GEOSCAN ID | 329346 |
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