Graphic Lake Pegmatites Lithium-Tantalum Claim Group, located in NW Ontario for PENDING OPTION
Option: The Graphic Lake claim group consists of ~950 hectares hosting a ~5.5 km long by 300m wide beryl-bearing pegmatite group trending NE-SW. Elevated Lithium values in surrounding host rocks imply a possible larger rare-earth mineralized system.
Contact: Troy Gallik
Access:
The Graphic Lake Pegmatites are located in the Code Township and Work Township of the Kenora Mining District. Access to the property is from Highway #71 to local gravel roads trending east and west.
Regional Geology:
The Witch Bay area comprises the eastern part of the Lake of the Woods volcanic-sedimentary Belt within the western part of the Wabigoon Subprovince. The following is excerpted from OFR5629, Trowell 1986
Supracrustal rocks in the area consist of east to east-northeast trending volcanics and sediments. Most volcanics range in composition from mafic to intermediate. Felsic volcanics are uncommon. The mafic volcanics are flows and crystal and lithic-crystal tuff with the felsic to intermediate volcanics arpresent as pyroclastics (which are rare other than in the area south of Gibi Lake). The sediments consist of sandstone, mudstone, uncommon conglomerate and chert, and magnetite ironstone. Ultramafic and mafic intrusions as sills have intruded the volcanic stratigraphy. Tight isoclinal folding occurred about east-to northeast-trending northeasterly plunging fold axes. These early folds were deformed and reoriented by intrusion of granitoid plutons within and bordering the greenstone assemblages. Major shearing occurred along east to east-northeast-trending zones – Gibi Lake Shear Zone. Diabase dikes intruded along north northwest trending fractures. Late northeast to north-northeast-trending fractures are common. Diabase dikes are displaced by these fractures and in places pseudotachylites are developed along the fractures. The volcanics, sediments and mafic to ultramafic intrusions have been metamorphosed to upper greenschist to lower almandine amphibolite rank. Retrograde morphism has occurred, primarily along shear zones. Quartz-tourmaline and tourmaline veins and masses have extensively intruded the volcanic and ultramafic to mafic intrusions and to a lesser extent the sediments.
Property Geology:
07/26/2017 (T Pettigrew) – A large number of white to pale pink pegmatites intrude the metasediments and metavolcanics in this area. They are roughly parallel to the foliation of the host rocks (040 to 050 degrees). Rudimentary zoning is evident in one pegmatite observed near the south end of Graphic Lake, where small quartz segregations were observed. The remainder of the pegmatites are homogeneous but some of the large ones have minor replacement or fracture filling zones. The major minerals present are pale green muscovite, biotite, quartz, white to pale pink microcline and microcline graphic granite. Trowell (1979) tentatively identified beryl from some of these pegmatites. Xenoliths of the host rocks are common (Storey, 1990). The beryl-bearing pegmatites are hosted in the Royal Island group metasedimentary rocks that are possibly correlative with nearby Warclub group metasedimentary rocks (Breaks et al., 2003).
Mineralization:
07/26/2017 (T Pettigrew) – Samples of the metavolcanic host rock show elevated lithium values. One sample near the main dyke contains 158 ppm and one at the south end of Graphic Lake contains 860 ppm (Storey, 1990). The pegmatites comprise a swarm with a breadth of least 300 m as delineated northward along Highway 71 from Graphic Lake. The strike length of the swarm has not been determined, although mapping by Trowell (1986) suggests at least a 5.5 km strike length. At Graphic Lake, dykes between 20 cm and 8 m in width, are mainly controlled by the foliation of host rocks (metawacke of medium metamorphic grade). These dykes are massive, garnet-muscovite white potassic pegmatite with subordinate sodic aplite and medium-grained garnet-muscovite granite. Muscovite is quite common and is typically lime green. Beryl appears as sparse, faint green crystals up to 2 by 4 cm. The pegmatite dykes hosted in clastic metasedimentary rocks near Graphic Lake were sampled at 3 different sites along Highway 71. These beryl-type pegmatites are mildly to strongly peraluminous (A/CNK = 1.092-1.598), depending upon the abundance of green muscovite. A significant degree of fractionation is evident in the low K/Rb (mean 44; range 32-52), K/Cs (mean 1488; range 754-2412) and Nb/Ta (mean 4.3; range 2.4-6.9) ratios derived from bulk samples. Anomalous levels of all the rare-elements were detected: Rb (mean 763 ppm; range 672-991 ppm), Be (mean 21 ppm; 4-50 ppm), Cs (mean 27 ppm; range 14-42 ppm), Ga (mean 60 ppm; range 54-64 ppm), Sn (mean 32 ppm; 10-69 ppm), Nb (mean 89 ppm; range 66-109 ppm) and Ta (mean 23 ppm; range 16-28 ppm). Local black grains of ferrocolumbite were documented in garnet-muscovite leucogranite in the midpart of the largest dike (on Graphic Lake), and specifically within a quartz-rich pod that also contains blue-grey, blocky potassium feldspar crystals up to 25 cm in diameter. An average of 9.56 weight % Ta2O5 was determined from 20 electron microprobe analyses of the ferrocolumbite grains. The ferrocolumbite is associated with iron-rich garnet with a composition of almandine (60-66% almandine, 31-36% spessartine, 2-3% pyrope). Ferrocolumbite (12-19 weight % Ta2O5) also occurs in the centre of a muscovite potassic pegmatite dike hosted by Gibi metasedimentary sequence rocks at Graphic Lake on Highway 71 (locality 01-FWB-123: UTM 422185E, 5495553N, Zone 15) (Breaks et al., 2003).