Summary:
Lithium occurs as Spodumene in pegmatites in the Georgia Lake area. The pegmatites are hosted by metasediments. All of the pegmatites are Albite-Spodumene type. Spodumene is the dominant Li-bearing mineral in all of the pegmatites.
Overall, the pegmatite dike internal zonation increases in complexity from north to south within the Georgia Lake pegmatite field:
• Nama Creek – the Main Zone North (MZN) and Main Zone Southwest (MZSW) have simple zonation: aplite or granitic border zone and a Spodumene zone with minor alternating aplite and pegmatite layers.
• Harricana (HAR), Line 60 (LIN60), and Conway (CON) have aplite or granitic border zone, a Spodumene zone and common alternating aplite and pegmatite layers.
The mineralization in the Property consists of coarse-grained fresh pale green spodumene crystals, oriented perpendicular to the strike of the pegmatite dike in homogeneous dikes, and randomly oriented within the inner spodumene zone in simply zoned pegmatite dikes. The spodumene may be altered to muscovite or fine-grained muscovite near the contacts with the host rocks and near diabase dikes.
The altered spodumene has low lithium content and a high iron content.
Nama Creek
The Nama Creek area holds most of the resource on the Georgia Lake Property within four pegmatite dikes. These dikes are: MZN, MZSW, HAR, and LIN60. Several other dikes have also been identified in the area and include Kenogamisis, Line 20, Camp 38, and Caral.
MZN
The MZN pegmatite consists of a main dike with known strike length of ~1,000 m and average width of 6.4 m plus many other stacked (often discontinuous) lenses oriented roughly parallel to the main dike. The strike averages at 235° E (or roughly SW) and the dip is steep at 70° to the NW. The pegmatites have been traced to a depth of around 340 m below surface. The dikes appear to be cut off on the western side due to a North-South striking trending fault. This fault has been observed in drillholes from 2011, namely NC-11-18, NC-11-19, and NC-11-20.
Mineralogy of the MZN pegmatites consists of quartz, albite and potassium feldspar, muscovite, and spodumene. Infrequent, thin, spodumene-absent dikes are present within the stacked system. Overall, the minerals are coarse to very coarse grained and equigranular. Spodumene is pale green to dark green where altered. Alteration is common where pegmatites are in close proximity to diabase. Zonation within these pegmatites is largely absent, though aplite layers have been observed within the dikes in some drillholes.
The pegmatites are hosted in weakly foliated to schistose metasediments and cross-cut by at least four diabase dikes. Two of the diabase dikes are sub-vertical and run approximately North-South, one through the central portion of MZN and the other adjacent to the large fault on the western side. Another diabase strikes roughly East-West and dips gently to the southeast. The fourth diabase is almost flat-lying and cuts the pegmatites off at depth. No drill holes have drilled to test continuation of pegmatite below this diabase. However, the same diabase was observed at MZSW (see below) where one historic hole (NC-60) managed to drill through it (150 m-wide) and intersected mica schist and Spodumene-bearing pegmatites.
MZSW
The MZSW pegmatite is located about 400 meters southwest of the MZN deposit and consists of a main dike with a few discontinuous, sub-parallel dikes. The known strike length is 275 m and the dike averages 5.5 m in thickness. It has been traced to a depth of approximately 200 m below surface. The strike averages 225° and the dip is steep at 70° to the NW.
Mineralogy of the MZSW pegmatites is similar to that of the MZN and consists of quartz, albite and potassium feldspar, muscovite, and spodumene. Infrequent, thin, spodumene-absent dikes are present within the stacked system. Overall, the minerals are coarse to very coarse grained and equigranular. Spodumene is pale green to dark green where altered. Alteration is common where pegmatites are in close proximity to diabase. Weak zonation is present with spodumene being more abundant towards the core of the dikes. Thin aplite layers have been observed within the dikes in some drillholes.
The pegmatites are hosted in weakly foliated to schistose metasediments and cross-cut by a roughly flat-lying diabase sill at depth. This has been interpreted to be the same deep, flat-lying diabase observed at MZN. Drill hole NC-60 has drilled through 150 m thick interval of the diabase sill and intersected mica schist and Spodumene-bearing pegmatites at the MZSW deposit.
Harricana
The Harricana area consists of two sub-parallel dikes, Harricana and the West Dike, as well as other minor sub-parallel dikes. The Harricana dike strikes 220° and the dip is steep at 60° to the NW. It ranges in thickness from 1 – 10 m and has a known strike length of 500 m. The West Dike strikes roughly 220° and dips 60° to the NW in the southern half of dike, however, the orientation of the dike changes to strike of 140°, dipping 60° to the SW, in the north. It has a known strike length of 650 m and width ranging in thickness from 2 – 10 m. These dikes have been traced to a depth of 170 m below surface.
Mineralogy of the Harricana pegmatites consists of quartz, albite and potassium feldspar, muscovite, and spodumene. Infrequent, thin, spodumene-absent dikes are present within the stacked system. Overall, the minerals are coarse to very coarse grained and equigranular. Spodumene is pale green to dark green where altered; sometimes it is altered to yellow-green muscovite. Weak zonation is present with spodumene being more abundant towards the core of the dikes. Thin aplite layers have been observed within the dikes in some drillholes.
The pegmatites are hosted in weakly foliated to schistose metasediments. One drillhole, HAR-22-02, intersected a diabase unit at depth, though this unit has not been observed in other drillholes in the Harricana area. Pye (1965) mapped diabase on surface approximately 150 m to the south of the known Harricana extent.
Line 60
Line 60 consists of one main dike that strikes 210° and the dip is steep at 70° to the NW. A few thinner, discontinuous, sub-parallel dikes are also present. The width is variable, ranging up to 20 m in the south. The known strike length is 600 m and the dikes have been traced to roughly 170 m below surface.
Mineralogy of the Line 60 pegmatites consists of quartz, albite and potassium feldspar, muscovite, and spodumene. Infrequent, thin, spodumene-absent dikes are present within the stacked system. Overall, the minerals are medium to coarse grained and equigranular. However, the dikes appear more granite-like, medium grained, and with less spodumene in the southern part of LIN60. Spodumene is pale green to dark green where altered. Zonation within these pegmatites is largely absent, though aplite layers have been observed within the dikes in some drillholes.
The pegmatites are hosted in weakly foliated to schistose metasediments. Pye (1965) mapped diabase on surface immediately to the south of the known LIN60 extent.
Conway
Conway consists of one main dike with a known strike length of 800 m and average width of 8 - 10 m; a few thinner, discontinuous, sub-parallel dikes are also present. The main dike strikes 210° and the dip is steep at 70° to the NW. It has been traced to 215 m below surface.
Mineralogy of the Conway pegmatites consists of quartz, albite and potassium feldspar, muscovite, and spodumene. Infrequent, thin, spodumene-absent dikes are present within the stacked system. Overall, the minerals are coarse to very coarse grained and equigranular. Spodumene is pale green to dark green where altered. Zonation is vague though is present as an aplite border zone with a spodumene-bearing core.
The pegmatites are hosted in weakly foliated to schistose metasediments.