KOMATIITE HOSTED NICKEL Source Active Pathway Trap - Chemical Scrubber Trap - Chemical/physical scrubber Trap - Physical throttle Modification Transporting magma through the Komatiite Formation Sulphur addition and saturation Metals sequester into sulphides Physical concentration of metal rich sulphides Modification of original ore body crust Critical Critical Process : ? Assimilation of A high degree of physical Early timing of sulphide Abrupt decrease in Tectonic High-degree mantle melting to produce ultramafic and komatiite Interaction with S Hydrothermal country rocks to interaction between sulphide concentration – relative magma flux to modification; e.g., magmas, plus felsic volcanic rocks (i.e., a bimodal volcanic rock High-flux magma pathways Lithospheric faulting rich rocks to induce Weathering alteration forming induce sulphur droplets and metals in a proportion of sulphide vs accumulate high folding, faulting association) sulphur saturation ore zones saturation komatiitic melt. silicate minerals proportion of sulphides duplication, remobilisation of massive sulphides Constituent Process Constituent What are the processes that that processes the are What process critical the control Thick, abundant, Bi-modal rock Archean/ Cumulate rich Ni content in olivine Fold hinges, Weathered Association with Morphology of Continental S rich rocks and S Changes in Changes in Veins/disseminated laterally extensive association (e.g., thick sequences of Proterozoic granite rocks, indicated by komatiite indicating lithosphere margins, komatiite Ni concentration in sulphides, Sulphide vs silicate and pyroxenes (e.g., intersecting faults, komatiites; ? concentration in morphology of zones that host Ni ultramafic rocks felsic volcanic rocks greenstone texture and eg., identifying high Ni tenors mineral ratios low Ni content in massive sulphides in identifying talc mafic rocks, high flux magma e.g., large scale/ komatiites chemistry (e.g., komatiite channels sulphides : with the potential coeval with rifting) indicating extensive, terranes, where chemistry pathways e.g., deep penetrating trace element silicates may felsic rocks alteration and to produce high-degree melting komatiites are most embayments and faults; rocks coeval chemistry which indicate high Ni in geochemical komatiite flows common (but also channelized with or indicators of indicates crustal sulphides) anomalies consider possible environments rifting. contamination) younger ages) Targeting How can we target each each target we can How process constituent Komatiite Archean and MgO >32% map Crustal Felsic volcanic rock Relative changes in Kimberlite Komatiite sulphide- Map of change in Fold hinge map Alteration mineral occurrence map Mafic rock Proterozoic rock age (m+c) Rhyolite map (m) Sulphidic rock map contaimination Komatiite with insitu occurrence map (m) komatiite thickness Structure occurrence map Ni tenor maps (m+c) silicate mineral primary morphology (m+g) map (m+WAROX+ occurrence map (m) map (m+c+WAROX) maps/plots (e.g., regolith map (m+reg) (m) map (m+g) complexity map (m) (m+c) texture map (m+c) in komatiites (m+g) WAMEX) (m+dhd+c+g+s+WA (m+chron+ENS) TiO2 vs Zr, Sm vs La, Ni/Cr map (m+c) ROX+WAMEX) Th vs Nb, Th vs YB; Dacite map (m) Intersecting faults m+c) Geochemical Komatiite rock age Alkaline rock age map (m+g) Quartz andesite Mafic rock thickness Volcanic facies Talc abundance map anomaly map map Ni/Ti Map (m+c) Magnetic structure map (m+chron) Ultramafic map (m) map (m) model (m+c) (WAROX+WAMEX+s) (m+c+hydro) occurrence map (m+chron+ENS) complexity map (g) (m+dhd) Felsic volcanic rock age map (m+chron) Mg# map (m+c) Coeval (sulphidic) Geochemical sediments Mafic classification anomaly soil map Rhyolite map (m) occurrence map map (m+c) Gravity structure (WAMEX+soil+c) Komatiite thickness complexity map (g) Alkaline rock (m+chron) ? map (m+g+dhd) Komatiite texture occurrence map map (m+c+WAROX) (m+c) BIF age and Basalt classification occurrence map Dacite map (m) map (m+c) Palaeocratonic (m+chron) boundary map (i) Carbonatite occurrence map (m+c) VMS age and occurrence map : Felsic volcanic rock (m+chron) age map (m+chron) Felsic volcanic rock occurrence map (m) Syenite occurrence map (m+c) Quartz andesite Pyroxenite m = mapping c = geochemistry s = reflectance spectroscopy hydro = hydrochemistry data g = geophysical interpretation chron = geochronology WAMEX= WAMEX database/reports reg = regolith map map (m) occurrence map i = isotopic ratios (e.g. Nd-Sm) dhd = drillhole database WAROX = WAROX database soil = soil map (m+c) Mappable Proxies Mappable Which layers are needed and how are they created they how are and needed are layers Which Blue text = geological proxy layer available in the Atlas [hyperlinked] Recommended reference = Geological Survey of Western Australia 2019, Mineral Systems Atlas: Komatiite Hosted Nickel system, Department of Mines, Industry Regulations and Safety, accessed date, <www.dmp.wa.gov.au/msa> Scale of use: Terrane vs District.