Quaternary deposits, most importantly glacial till, represent sedimentary materials derived directly from the bedrock that have been transported in the glacial flow direction. The till therefore contains a mineralogical record of all of the rock types the ice has encountered. What is important for exploration is that some amount of these mineral grains in the till are unique to certain host rocks and their ore deposits. For example diamonds, carbonatites, PGE-mineralization, gold, Li ores and some gemstones are each associated with their own distinctive suite of indicator minerals (gold of course is its own indicator). The key innovation that is required for this type of exploration is the ability to find and recognize all important indicator minerals amongst the many trillions of grains in a given sample, something that requires detection limits on the order of a few ppq (part per quadrillion).
An example of exploration Method for diamonds:
Since 1994, GTK has been providing customized, high quality diamond exploration services with complete confidentiality to companies both within Finland and abroad. We specialize in laboratory services and exploration techniques from regional through to prospect scales GTK.
Our scanning electron microscope with attached EDS-analyzer can be used to confirm the optical recognition of indicators and give a rapid initial estimate of composition without coating or preparation of the grains.