en.Wedoany.com Reported - Critical Resources (ASX:CRR) has identified granitic pegmatites as priority targets for follow-up lithium exploration in the Northern Corridor of the Mavis Lake project in Ontario, Canada.
Whole-rock geochemical analysis has returned potassium-to-rubidium ratios as low as 17.4, along with elevated lithium pathfinder elements, in pegmatites located approximately 4 kilometres north of the project's existing Mineral Resource Estimate (MRE).
The most fractionated sample returned 5,510 ppm rubidium (Rb), 221 ppm caesium (Cs) and 22.9 ppm tantalum (Ta). Other samples recorded potassium-to-rubidium ratios below 40, rubidium values exceeding 2,000 ppm, and tantalum values up to 53 ppm.
Critical Resources said these results are consistent with highly evolved lithium-caesium-tantalum (LCT) pegmatite systems and will help guide further exploration. All samples returned low lithium oxide values, with the company noting that drilling is required to confirm lithium mineralisation.
A 10-day field program collected 106 rock samples across the survey area, including samples from 14 pegmatite bodies, six of which were newly identified. Critical Resources also mapped 161 outcrops and collected 74 structural measurements.
The company said the strongest fractionation signatures occur within the Northern Claims package, acquired in August 2025. Pegmatites sampled in the Corona zone generally returned higher potassium-to-rubidium ratios and lower pathfinder element enrichment, indicating lower degrees of magmatic fractionation.
Managing Director Tim Wither said the results focus the company's exploration efforts on granitic pegmatites. Wither noted that the results significantly refine exploration priorities, highlighting granitic pegmatites whose geochemical signatures are consistent with highly evolved LCT systems.
The company plans to integrate these results with geological, structural, geophysical and historical datasets to rank targets. Follow-up work includes further mapping, surface geochemistry, mechanical stripping and reconnaissance diamond drilling.
The Mavis Lake project hosts an Inferred Mineral Resource Estimate (Inferred MRE) of 8 million tonnes (Mt) at 1.07% lithium oxide. The project is located approximately 19 kilometres east-northeast of Dryden in northwestern Ontario.
