new zealand’s clean technology mineral potential · 2019. 2. 9. · gns science talk outline •...
TRANSCRIPT
GNS Science
New Zealand’s Clean Technology Mineral Potential
Regine MorgensternRose Turnbull, Matt Hill, Patti Durance, Mark Rattenbury, Rob Smillie, NZP&M
GNS Science
Talk Outline
• What are ‘clean technology’ minerals and how are they used
• The mineral systems concept
• Mappable criteria of the mineral system
• Rare earth element mineral potential of New Zealand
• Lithium mineral potential of New Zealand
• Next steps and opportunities
Source: https://ww2.frost.com/
GNS Science
Introduction
‘Clean-tech’ minerals (aka ‘green’/‘strategic’ minerals or ‘critical elements’) – essential to support New Zealand’s transition to a low-carbon economy
Metals (and mining) are required for a no/low-carbon future
Sources: www.icmm.com; www.stuff.co.nz
Clean technology minerals
• Elements crucial to society for economic growth and/or national security, but which are vulnerable to supply disruption
• No practical substitutes: they are in high demand• There are currently 23 – including Co, Li and REE
GNS Science
Introduction
Clean-tech mineral uses:
Wind turbinesSolar batteriesElectric and hybrid vehicle batteries
Sources: AGI 2018; www.newzealandphoto.info
1x 3 MW turbine = 2 tonnes REE
64,000 electric vehicles by end of 2021
Demand for these clean-tech minerals is high and continues to grow
GNS Science
Introduction
• Commodities of REE, Li and Co are poorly understood• Importantly, what is currently defined as a critical mineral can change
with rapidly evolving technology and social and political changes
Need to understand all of NZ’s mineral wealth resource in order to adapt to future supply and demand constraints of low-carbon technologies
New Zealand’s first clean technology minerals study:• Jointly-funded GNS Science – NZP&M project to examine the potential for REE, Li and
Ni-Co mineralisation at a broad regional scale• To identify areas of higher potential, and rule out other areas based on current
knowledge and data• To identify knowledge gaps so as to improve confidence in REE, Li and Ni-Co potential• Provides a framework for other commodity studies (e.g. Au, Ag, PGE, W, base metals)
GNS Science
The Mineral Systems Concept
• Theoretical model to conceptualise ore deposits at various temporal and spatial scales
• Ore deposits are small expressions of larger earth system processes that occur before, during and after deposit formation
• Derived from the petroleum system concept• Mineral system components:
– Energy source– Fluid, ligand and ore sources– Enrichment and focusing mechanism– Trap– Surface expression
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NO DEPOSIT
NO DEPOSIT
NO DEPOSIT
Fluids & ligandor ore source
EnergySource
Enrichment &focusing Trap Surface
expression
Regional scale components
District scale
Ore deposit
Source: Hagemann et al. 2016
GNS Science
The Mineral Systems Approach – Intrusion-Related REE
Component Critical processes¥
Constituent processes§
Targeting featuresŦ Scale* Mappable criteria
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Fluid migration / mixing Zoned alteration facies S-M Key alteration mineral occurrence (e.g. greisenisation, sulphide minerals)Residence time Mineralogical / textural S Sampled rock pathfinder elements
Laterites, saprolite and clays S-M Occurrence of clays (especially halloysite), saprolite, lateritesAccumulation of monazite, zircon, xenotime, allanite, thorite, uranothoriteSampled REEs & pathfinder elements in stream / pan concentrate samplesMapped Quaternary depositsRadioactivity
Fluid-wall rock reactions Alteration + precipitation along structures S-MFluid mixing / dilution Changes in mineral stabilities S
Sampled rock ore elements (i.e. REE content)Key REE mineral occurrence (e.g. monazite)
Pressure decrease Structures, cavities, shallow emplacement S-L Mapped Paleozoic and Mesozoic faultsBoiling / effervescence Volatile loss S-M Hydrothermal alterationChange in temperature Zoned alteration facies / crystallisation sequence S-M Zoned alteration assemblageNormal faulting Cross-cutting dilatational structures / textures S-L Mapped Paleozoic and Mesozoic extensional faultsDelamination Metamorphic core complex / half-graben basins L Mapped Mesozoic core complexes & brecciaDike-swarm intrusion Presence of dikes M-L Mapped/sampled dikes
Igneous fractionationMapped/sampled pegmatitesSampled whole-rock F contentF-rich mineralogy
Degree of partial melting Igneous geochemistry (Fe:Mg, HFSE content, ASI index, low-Ca)Melting of enriched / previously extracted mantle Key mineral occurrence (feldspathoids, alkali amphiboles / pyroxenes)
Mapped intrusive suites in QMAPAeromagnetics
Liquid immiscibility Chemical / mineralogical S-M Mapped/sampled pegmatites, carbonatites, fenitesHeating of country rock Alteration zones S-M Mapped/sampled alteration zones (e.g. sulphide / carbonate minerals)Mantle melting / degassing Involvement of mantle-derived CO2 S Mapped/sampled carbonatites / carbonate mineralsDecompression / ascent Shallow emplacement M-L Mapped geological structuresAsthenospheric upwelling Alkaline igneous rocks / carbonatites M-L Mapped intrusive suites in QMAPDecompression melting Crustal thinning / extension L Crustal / trans-lithospheric structures
5. Surface expression
1. Energy source
2a. Fluid and ligand source
2b. Ore source
3. Enrichment and focusing mechanism
4. Trap
Alkaline geochemistry
Alkaline igneous rocks / carbonatitesCooling & fractional crystallisation
Alteration rock types (altered, veins, breccia/conglomerate, metasomatic)
Crystallisation of ore / gangue minerals REE mineralogy
Magma cooling Igneous relationships and fractionation M-L
S-M
M-L
M-L
S
Presence of elevated F in magma / hydrothermal fluids
Intra-plate magmatism
Mantle melt generation
Granitic melt generation
Mantle magmatism
Complexing of REEs
Extensive fractionation
Regional extension
Change in physical conditions
Change in chemical conditions
Involvement of F in melt &/or hydrothermal (magmatic / meteoric) fluids
M
Cooling
Chemical / mechanical weathering (± transport & deposition)
Weathering (± erosion) Heavy mineral, Th & U accumulation, black sands, placers, etc. within Quaternary deposits
Building on the REE mineral systems model of Morgenstern et al. (2017)
GNS Science
The Mineral Systems Approach
Mappable criteria• Parts of the mineral system that can
be represented spatially• Represent all five components• Were identified for all three mineral
systems• Data were extracted from existing
databases, open access mineral reports and other published and unpublished literature
• New data were also acquired• GIS-based expert-weighted spatial
modelling approach was used to create the mineral potential maps
Patti will discuss these, and Ni-Co potential, in more detail in her talk
GNS Science
Mineral Potential Maps – REE
Where might REE deposits form in New Zealand?
1. Carbonatites2. Alkaline igneous intrusions3. Placers4. Ion-adsorption5. Laterites6. By-products, co-products, waste-products7. IOCG deposits8. Seafloor deposits
GNS Science
Mineral Potential Maps – REE
Mineral potential modelling of REE mappable components
Mineral system components
Final mineral potential models
Mappable criteria
GNS Science
Areas of highest potential:• Placers sourced from REE-rich
alkaline intrusions: West Coast beach sands and paleoplacers
• Alpine Dike Swarm carbonatites: Up to 1.25 wt% light REE
Opportunities to refine the model• Targeted stream sediment sampling
and analysis (West Coast beaches, catchments draining carbonatite dikes around Haast)
• Targeted sampling and analysis of in situ plutonic sources
Mineral Potential Maps – REE
1342 ppm1439 ppm
REE Heavy Mineral Samples(analysed for this study)
500-600 ppm
GNS Science
Mineral Potential Maps – Lithium
Where might lithium deposits form in New Zealand?
1. Pegmatites2. Brines3. Hydrothermally altered clays
No known occurrences of Li-rich minerals
No prior exploration for lithium (except for extraction from geothermal brines)
GNS Science
Mineral Potential Maps – Lithium
Mineral potential modelling of lithium mappable components
Mineral system components
Final mineral potential models
Mappable criteria
GNS Science
Mineral Potential Maps – LithiumWEST COAST COROMANDEL TAUPO-BAY OF PLENTY
STEWARTISLAND
CANTERBURY
TVZ
Hohonu Range
Lyell RangeCVZ
Mount SomersVolcanic Group
GNS Science
Mineral Potential Maps – Lithium
New areas of interest• Taupo Volcanic Zone: Hydrothermally
altered rhyolitic lake deposits, extensional faults, current hydrothermal activity
• Hohonu Range, Lyell Range: Fractionated granitoid rocks = potential for pegmatites
Opportunities to refine the model• Targeted analyses of lithium & key
pathfinder elements from samples in Petlab
• Sampling of pegmatites/hydrothermally altered clays in prospective areas
Taupo Volcanic Zone
Hohonu Range
Lyell Range
GNS Science
Summary
• This project has proven successful in identifying broad areas with higher potential and ruling out other areas based on current knowledge and data
• REE potential: highest in West Coast alkaline plutons and in placer deposits derived from them
• Lithium potential: highest in central North Island, and West Coast granitoids Available as Mineral Reports to download from www.nzpam.govt.nz
• Revealed data gaps, and the potential to improve the models with further sampling and analysis• Very low or no potential areas (grey) are unlikely to change with further work
• Some areas of low potential (blue-green) may increase with additional studies/analyses
• Areas of moderate-high potential (yellow-red) are good starting points for further detailed studies
GNS Science
Next Steps
• Address data gaps from these studies in regions identified as having high potential (e.g. targeted geochemical sampling of hydrothermally altered clays in the Taupo Volcanic Zone)
• Undertake similar studies for other critical minerals using the same approach, to develop a national-scale, consistent dataset (e.g. Au, Cu, PGE, W, aggregates)
• Consider offshore critical mineral potential (e.g. Co, Cu, REE, phosphate) using the same mineral systems approach
• Advocate for the collection of consistent, seamless national-scale datasets
Watch this space!