Applied Quaternary geology and till geochemistry of the Loch Lomond Region, Cape Breton Island, Nova Scotia

Southeastern Cape Breton Island is host to several former industrial mineral and base metal mines discovered by traditional prospecting methods, but present exploration is hampered by a complex glacial history. Late Wisconsinan ice advances resulted in the deposition of five distinct tills. The basal grey till (LL-1) is a compact, fine-grained till found in local depressions. The regional red till contains 10–30% clasts and 20–30% clay and was deposited by an eastward ice advance (LL-2). Northward (LL-3) and southward (LL-4) ice flows were responsible for two hybrid tills that formed in part through inheritance and overprinting. The local stony till was formed by a southeasterly ice-flow event (LL-5) and contains 35–75% angular local clasts and less than 10% clay. The southern half of the study area is dominated by 50 m high bedrock-cored till ridges. Inter-ridge areas are overlain by organic deposits and glaciofluvial sediments which provide anomalous geochemical values. Samples were collected at 3–5 km spacing and the <0.063 mm fraction was analyzed. Till geochemical patterns are complex as a result of lithological repetition, complex glacial history and numerous mineralization types. Detailed analysis of sedimentology resulted in the recognition of individual tills at geochemical sample sites. Till pebbles could be used to help delineate bedrock boundaries. Additional sampling of the regional red till could be conducted in the Loch Lomond valley for as yet undetected mineralization located west of the study area. Complex Ba patterns require a subtle sampling strategy for future exploration. The local stony tills in the Mira Hills are recommended as the best stratigraphic target to delineate Cu (Au) values in rocks of the Stirling Group.