Commodity: Tin, Tungsten, Graphite
Claim block number (units): 9281 (118)
NTS Location: 21 G/06
Contact Information: 506-466-8164
The Basswood Ridge prospect is located about 95 km southwest of Fredericton and 29 km west-southwest of the Clarence Stream gold deposit in southwestern New Brunswick. In the late fall of 2019, prospecting in the area led to the discovery of a large quartz vein hosted by graphitic schist. In 2020, further prospecting work (including trenching) uncovered a mineralized/greisenized two-mica granite.
The area is underlain by sedimentary rocks of the Ordovician Kendall Mountain Formation that are in faulted contact with the Silurian Digdeguash Formation (Fig. 1). These rocks have been metamorphosed to the greenschist facies and were later thermally affected by the intrusions of the Silurian Mohannes Granodiorite, and a newly discovered Devonian granite, which is referred to as the Splan Pond Granite. At the type locality, the Splan Pond Granite consists of light greyish white, medium- to coarse-grained, equigranular, muscovite - biotite granite (Fyffe, 2021). It is also exposed in an exploration trench about 3.5 kilometres to the north of Splan Pond (Lat. 45.285491; Long. -67.334996) where it is highly greisenized and contains abundant muscovite, arsenopyrite, pyrite, purple and green fluorite, and tourmaline (Holmes, 2019). Based on the limited exposure, the Splan Pond pluton is an elongate body that underlies an area of about 3 km2 (Fig. 1). The characteristics of this highly evolved granite and associated alteration and Sn-W mineralization have similarities with other plutons and associated mineralization in the Pleasant Ridge and Mount Pleasant areas located further to the east.
Quartz veins: A very large quartz veined outcrop (Figs. 2a, b, c) was discovered in the fall of 2019 near the Basswood Ridge and Robinson roads in a previously unexplored area. The quartz vein system occurs along a major northeast-striking fault that separates sedimentary rocks of the Ordovician Kendall Mountain Formation from the sedimentary rocks of the Silurian Digdeguash Formation to the north (Fig. 1). Locally, an assemblage of pyrite-chalcopyrite-arsenopyrite occurs as coarse disseminations and impregnations in fractured and brecciated sections of the vein. Preliminary pXRF analysis of the quartz vein material yielded up to 1300 ppm As and up to 52 g/t Ag. The veins are hosted by graphitic schist with flaky graphite, pyrite, and drusy quartz crystals. The Silurian Mohannes Granodiorite outcrops approximately 1.5 km southeast of the vein system. Moreover, the occurrence of randomly oriented long and prismatic andalusite(?) crystals within hornfelsed graphitic schist suggests that the area may be underlain by a buried granite.
Greisen: About 500 m southwest of the main quartz veined area, a greisenized two-mica granite, which appears to differ from the Mohannes Granodiorite, was uncovered through trenching. This granite, now known as the Splan Pond Granite, is strongly greisenized and contains abundant muscovite, purple and green fluorite (as disseminations, along fractures and in quartz veins), tourmaline, and arsenopyrite (Fig. 3). In places, the granite is interlaced with (feldspar)-quartz veins that contain galena, pyrite, and arsenopyrite (Fig. 4). Analysis of a grab sample from the vein material yielded 2 g/t Ag, 13 ppb Au, 24400 ppm As, 70.9 ppm Bi, 2200 ppm Pb, 147 ppm Mo, and 7.6 ppm Sb, consistent with the mineralogy observed. Portable XRF analysis of greisen float collected from the area yielded up to 616 ppm Sn, 941 ppm W, 63.3 Bi and 4724 ppm As. Grab samples taken from the greisenized granite exposed in trenches (Lat. 45.285491; Long. -67.334996) returned up to 8430 ppm As, 2330 ppm W, 606 Sn, 720 ppm Li, 660 ppm Rb and 60 ppm Mo.
Graphite Carbon: A graphite-bearing (flaky fabric) hornfelsed metasedimentary rock (Fig. 5) was also noted approximately 80 m northeast of the quartz veined area. Metamorphism has increased the grain size of graphite flakes locally. Chemical analysis (Infrared quantification by Activation Laboratories Ltd.) of two grab samples from a graphite-rich schistose rock returned 4.58% C and 4.73 % C. These grades are equivalent to or better than the Matawinie graphite deposit (Probable Reserve of 59.8 million tonnes grading 4.35% graphitic carbon (Cg); Monde Graphite Inc., October 25, 2018 press release) located about 150 km north of Montreal.