Search Minerals, through its wholly-owned subsidiary Alterra Resources Inc. (Alterra), owns Deep Fox and nearby Foxtrot, as well as a number of mineral prospects on its 100% owned Critical REE District spanning approximately 64 km.
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Summary:
Rare earth element (REE) and rare earth metal deposits can be divided into two main classifications: primary magmatic REE deposits and secondary REE deposits. The vast majority of deposits are primary magmatic and many of the secondary ones are proximal to REE-enriched primary magmatic sources. Most magmatic deposits are related to mantle-derived magmas and/or magmatism associated with crustal rifting. Metamorphic equivalents of these main categories are also known but not distinguished in this classification.
Primary magmatic deposits can be subdivided into peralkaline oversaturated, peralkaline undersaturated, and carbonatite deposits. Peralkaline deposits, both oversaturated (quartz-bearing or quartz normative) and undersaturated (nepheline-bearing or nepheline normative) are mainly HREE- enriched, while carbonatite deposits are commonly LREE-enriched; some carbonatite high-level vein systems are also HREE-enriched. Peralkaline rocks and carbonatites are known to occur in similar geological settings and can be spatially related.
Primary magmatic REE deposits are formed by concentration of REE and other incompatible elements (e.g., Zr, Nb, fluorine (F), U, Th, hafnium (Hf)) in the upper portions of magma chambers. These incompatible element-enriched magmas are either crystallized in place, are transported to locations proximal to the magma chamber, or are transported to surface and deposited as volcanic products.
Peralkaline oversaturated volcanic-hosted deposits are rare but known to occur (e.g., Foxtrot, Deep Fox; Brockman, Australia).
Deep Fox and Foxtrot occur in the 64 km long Fox Harbour Volcanic Belt (FHVB), which ranges in width from less than 50 m in the northwest to three kilometres in the east. Units dip steeply in a northerly direction and generally strike westerly to northwesterly, parallel to bounding faults to the north and south. The FHVB contains one peralkaline belt in the northwest and three peralkaline belts in the east, these belts of bimodal rocks dominated by REE-bearing felsic peralkaline flows and ash-flow tuffs and mafic to ultramafic volcanic and related subvolcanic units.
The three bimodal belts in the FHVB, from north to south: the Road Belt (RB), the Magnetite Belt (MTB) and South Belt (SB), have been the focus of REE exploration.
Deep Fox is hosted in the RB. In the Project area, the RB consists of, from north to south: 1) northern comendite, 2) anorthositic suite rocks consisting of anorthositic gabbro and anorthosite, 3) nonperalkaline rhyolite, 4) southern comendite, 5) mafic and ultramafic volcanic rocks, 6) mineralized pantellerite with interbedded non-peralkaline rhyolite and mafic volcanic rocks, and 7) a footwall nonperalkaline rhyolitic ash-flow tuff. Minor units of locally derived volcanogenic sediments, mafic volcanic flows, and related subvolcanic units and pegmatites occur throughout this sequence. Mineralized units are commonly interbedded with mafic to ultramafic volcanic units, quartzite, and locally derived volcanogenic sediments. Most units generally dip 75° to 85° northerly and drill data indicates that the mineralized zone plunges towards the northeast. The anorthositic suite and mineralized units form a prominent east-west trending ridge in the area. At Deep Fox the pantellerite mineralization is up to 42 m in thickness and typically averages 15 m to 30 m in thickness.
Foxtrot is hosted in the MTB. In the Project area, the MTB consists of pantellerite, comendite, nonperalkaline rhyolite, and mafic to ultramafic volcanic and related subvolcanic units. Mineralized units commonly range from five metres to 20 m in thickness. Mineralization is up to 100 m in thickness (comendites plus pantellerites) at Foxtrot, medium to high grade mineralization (pantellerite) is up to 25 m in thickness and typically averages 10 m to 14 m in thickness.