Exploration for buried mineralised pegmatites is challenging because of their lack of distinctive geophysical signatures. The GREENPEG project (project GA869274, EU HORIZON 2020 programme) has developed a multi-method toolset based on an improved understanding of pegmatite properties, settings and genesis.

The Leinster pegmatite belt is located within the narrow (<3 km) but extensive, SW-NE trending East Carlow Deformation Zone (ECDZ) which forms the eastern contact of the late-Caledonian composite Leinster Batholith that intruded previously deformed Lower Palaeozoic metavolcano-sedimentary rocks. The unexposed spodumene pegmatites form up to 20 m thick NW-dipping sheets.

Shear zones/faults, and lithological boundaries can be delineated using airborne geophysics on a province and district scale. At prospect scale, the ECDZ is clearly visible in electrical resistivity tomography (ERT) measurements that also allow the identification of weathered granite, faults, and high resistivity areas prospective for pegmatites.

Lithium concentrations in soils and certain minerals in stream sediments (spodumene, garnet, kaolinite) provide successful pathfinders for subcropping pegmatites.

Orientation data for different structures, obtained from borehole logging combined with field and drill core observations, enabled the identification of several generations of (barren) pegmatite and indicate a relatively late emplacement age for the spodumene pegmatites. This is consistent with quartz from the spodumene pegmatites having lower Ti and higher Al, Li, and Ge concentrations than that in barren pegmatites, indicating more evolved compositions.

We show that complementary geophysical, geochemical, and geological methods can be successfully used for spodumene pegmatite exploration. The data furthermore enhanced our understanding of pegmatite emplacement in SE Leinster.

Exploration for buried pegmatites presents a challenge, mainly caused by weak geophysical signals due to commonly low petrophysical contrasts between pegmatites and wall rocks. However, dedicated petrophysical studies and a better genetic, structural, and lithologic understanding of pegmatites motivate reassessment of the geophysical methods pool and open the door for refined pegmatite exploration workflows. The EU Horizon 2020 GREENPEG project developed a toolset for this purpose, including a comprehensive petrophysical database for European pegmatites, that is both cost-effective and promotes sustainable exploration, while combining geophysical and geochemical exploration methods.

The Jennyhaugen quarry close to Drag, Northern Norway, hosts N(iobium)-Y(ttrium)-F(lourine) pegmatites and served as one of the field labs for the development of the exploration toolset. We present here insights gained during comprehensive field tests for method selection and combinations, while we focus on the geophysical exploration tools.

NYF pegmatites often have a geochemical halo enriched in the radioelements thorium, uranium and potassium, highlighting gamma-ray spectrometry as a successful tool to be used in areas with no or little soil cover. When targeting hidden pegmatites, depth penetrating methods like ground penetrating radar and electrical resistivity tomography, in combination with legacy drill core lithology, ground magnetics, gravity and innovative piezoelectric sensing proved in part very successful. The combination of the individual methods closes interpretation gaps and besides identifying buried pegmatites, we also improved understanding of the settings and geometries of pegmatites.

As an innovation in the EU-funded H-2020 GREENPEG project (GA 869274), the Geological Survey of Norway (NGU) has developed a state-of-the-art piezoelectric seismograph (PES) as a valuable contribution to pegmatite exploration. The instrument utilizes the piezoelectric effect which describes the conversion of mechanical pressure into electrical energy, or vice versa. This technology has been leveraged to detect quartz, for gold exploration since the 1970s. NGU applied newest electrotechnology and data processing to customize it for granitic pegmatite exploration. The pilot was deployed in different settings e.g. at the GREENPEG demonstration sites in Tysfjord/Drag pegmatite field, Norway, where the pegmatite occurs in the Tysfjord granitic gneiss intrusion as lens-shaped bodies. The pegmatite mainly consists of feldspar, plagioclase, biotite, and a quartz core with dominant accessory minerals of Niobium, Yttrium and Fluorine (NYF). The survey detected buried quartz deposits at a depth of 5–10 m, using 100g minimal invasive explosive charges. The results were confirmed by drill cores. At another site in Tysfjord/Håkonhals the quartz was found at even 15–25 m depth embedded in the host rocks amphibolite and gneiss, using an 80 kg drop-weight with minimal environmental impact.

Since this novel piezoelectric seismograph is exclusively sensitive to the presence of quartz, it has a lower ambiguity compared to other geophysical methods applied in pegmatite exploration and is a sustainable and cost-efficient method for pegmatite exploration, both as a stand-alone method and in combination with other methods on brownfields and greenfields.

LCT pegmatites are the main solid rock resource for battery lithium with a market share of over 50%. The focus of current and future exploration and mining beyond the current main supplier Australia is emerging in southern Africa and Canada. Europe will only be able to cover a good quarter of its own requirements if the currently explored deposits are all mined. Non-European LCT pegmatites are therefore becoming increasingly important. The EC is therefore striving for raw materials partnerships ie with Namibia. But Europe is not alone here. China in particular has become active in several African countries, both entrepreneurially and politically. Investments by private Chinese companies have exceeded the financial resources provided by the EC for the development of raw materials partnerships many times over. Furthermore, European companies play a subordinate role, own mining operators are missing, as are take-offs or backward integration of European OEMs

More than this, Chinese companies are increasingly getting involved in or taking over exploration projects. However, the rush for lithium in Africa risks fueling corruption and failing citizens. The presentation provides an overview of the deposits and geopolitical ambitions of the main consumer states as well as the supplier countries in the region under review and ventures a forecast for securing Europe's raw materials in global competition.