Two generations of cassiterite in albite- from SE Ireland: Implications for tin mineralisation in lithium pegmatites

Kaeter, D., Barros, R., Menuge, J.F., Chew, D.M., Badenszki, E.

3rd International Critical Metals Conference Edinburgh May 2, 2019 Deemed critical for U.S. economy (U.S. Interior Department, 2018)

Tin: a critical metal? Latest tech gadgets (2000–1000 BC)

ITA (2018)

Metropolitan Museum of Arts 47% ITA (2018) . Displays . Aircrafts . Solar panels

Indium tin oxide Increasingly used in Potential use in conventional car batteries anodes of Li-ion batteries Shallow . Veins and stockworks → Hydrothermal Distance to granite ↓ . Rare-element pegmatites → Magmatic? Temperature ↑ . Greisens and skarns → Metasomatic Deep

Tin deposits Regional geology

more distal, Au shallower Sn-W 73 proximal, Li(-Sn-Ta) deeper

Data source: Geological Survey Ireland . Spodumene

Pegmatite

Data source: Geological Survey Ireland lithologies . Spodumene pegmatite . Albitites (Ab*)

Pegmatite

Data source: Geological Survey Ireland lithologies . Spodumene pegmatite . Albitites (Ab*) . Quartz- assemblages (QMA)

Pegmatite

Data source: Geological Survey Ireland lithologies . Spodumene pegmatite . Albitites (Ab*) . Quartz-muscovite assemblages (QMA)

Pegmatite

Data source: Geological Survey Ireland lithologies Trace-element zoning in muscovite Kfs

Ab*

Ab* Kfs I Kfs II

Ab* Kfs III

Ab*

Kaeter et al. (2019): Geochimica Cosmochinica Acta 240: 98-138 1000 µm The magmatic-hydrothermal transition

Kaeter et al. (2019): Geochimica Cosmochinica Acta 240: 98-138 The magmatic-hydrothermal transition

Kaeter et al. (2019): Geochimica Cosmochinica Acta 240: 98-138 The magmatic-hydrothermal transition

Kaeter et al. (2019): Geochimica Cosmochinica Acta 240: 98-138 III II

I

II

III Cassiterite

SnO2 BSE Ab 250 µm Cassiterite Ms Ab

1 Chl Laser pit Ap

Laser pit Qz

2

Ms CGM = ColumbiteQz group EDS 250 µm Cassiterite CL 250 µm

Cassiterite 2.3 Ab 2.2 1 2.1 1 1 Alteration? When? 1

2.1 2.1 2.3 2.2 CGM 2.2 Turbid zoning in 2.1 2.3 Trace-element zoning in cassiterite

2 III 1 II 2 2 I

II

III

500 µm Zoning and deformation

2 III 1 II 2 2 I Pre-2 fracturing and alteration Syn-2 fracturing? II

III

500 µm 500 µm Melt and fluid evolution 2 2 1*III 2 1* 1 1* 2 1 1 1* II 2 2 2 I

II

III

500 µm 2 Magmatic cassiterite: . Less fractionated (low Ta/Nb, Hf/Zr) . High T, higher impurities 1 2 1* 1 1* 2 Hydrothermal cassiterite: . Highly fractionated (high Ta/Nb, Hf/Zr) . Low T, lower impurities 2 2 1* Supported by melt and fluid inclusion 1 1 studies as well as petrographicI and geochemical observations of cassiterite in other pegmatites. 100000

(e.g. Rao et al., 2009; Dewaele et al., 2011; BorisovaII et al., 2012; Llorens González et al., 2017) 2 III Magmatic (1) vs 1 Hydrothermal (2)

1000 Cassiterite in the magmatic–hydrothermal transition

Stage I: Magmatic . Fractional crystallization from silicic melt . Enrichment in incompatible elements incl Sn Stage II: Magmatic–metasomatic . Unmixing into two melts and fluid . (1) Magmatic cassiterite from silicic melt . (1*) Deformation and dissolution–reprecipitation Stage III: Metasomatic–hydrothermal . Precipitation of albite and hydrothermal muscovite . Hydraulic fracturing . (2) Hydrothermal cassiterite 04/03/2019 Kaeter et al. Slide 26

Reading the mineralogical record of multistage is a key to decipher complex crystallisation processes. 04/03/2019 Kaeter et al. Slide 27

Cassiterite precipitates after the magmatic first stage of pegmatite formation from both polymerized melt and later aqueous fluid. 04/03/2019 Kaeter et al. Slide 28

So what? 04/03/2019 Kaeter et al. Slide 29

Mining: Tin (and tantalum) is concentrated in metasomatic units and might remain in the ground if the pegmatite is specifically mined for spodumene.

Exploration: Cassiterite as indicator mineral; mineral texture and inclusions can tell us if its source is pegmatite or vein-system Contact: [email protected] @DavidKaeter

Thank you for your attention. Special thanks to the Warwickshire Geological Conservation Group (WGCG).

With support from:

This presentation has emanated from research supported in part by a research grant from Science Foundation Ireland (SFI) under Grant Number 13/RC/2092 and is co-funded under the European Regional Development Fund and by iCRAG industry partners. References Barros R, Menuge JF (2016) The origin of spodumene pegmatites associated with the Leinster Granite in southeast Ireland. The Canadian Mineralogist 54:847–862. Borisova AY, Thomas R, Salvi S, Candaudap F, Lanzanova A, Chmeleff J (2012) Tin and associated metal and metalloid geochemistry by femtosecond LA-ICP-QMS microanalysis of pegmatite–leucogranite melt and fluid inclusions: new evidence for melt–melt–fluid immiscibility. Mineralogical Magazine 76:91–113. Dewaele S, Henjes-Kunst F, Melcher F, Sitnikova M, Burgess R, Gerdes A, Fernandez MA, Clercq FD, Muchez P, Lehmann B (2011) Late Neoproterozoic overprinting of the cassiterite and columbite-tantalite bearing pegmatites of the Gatumba area, Rwanda (Central Africa). Journal of African Earth Sciences 61:10–26. ITA (2018) ITA Survey shows weaker tin use growth in 2018. Available at internationaltin.org/ita-survey-weaker-tin-use-growth-2018/ (accessed 18/04/2019). Kaeter D, Barros R, Menuge JF, Chew DM (2018) The magmatic–hydrothermal transition in rare-element pegmatites from southeast Ireland: LA- ICP-MS chemical mapping of muscovite and columbite–tantalite. Geochimica et Cosmochimica Acta 240:96–130. Kaeter, D., Barros, R., Menuge, J.F., in preparation. Metasomatic-hydrothermal high-field-strength element (Ti, Zr, Nb, Hf, Ta, U), tin and base metal mineralization in albite–spodumene pegmatites from SE Ireland: Lithium pegmatites in late-orogenic Li-Sn(-W) systems. Llorens González T, García Polonio F, López Moro FJ, Fernández Fernández A, Sanz Contreras JL, Moro Benito MC (2017) Tin-tantalum-niobium mineralization in the Penouta deposit (NW Spain): Textural features and mineral chemistry to unravel the genesis and evolution of cassiterite and columbite group minerals in a peraluminous system. Ore Geology Reviews 81:79–95 Rao C, Hu H, Wang RC, Zhang WL (2009) Complex internal textures in oxide minerals from the Nanping No. 31 dyke of granitic pegmatite, Fujian province, southeastern China. The Canadian Mineralogist 47:1195–1212. U.S. Interior Department (2018) Final List of Critical Minerals. Available at federalregister.gov/documents/2018/05/18/2018-10667/final-list-of-critical- minerals-2018 (accessed 18/04/2019). Free stock images from pexels.com, pixabay.com and unsplash.com