Gold resources in undiscovered orogenic gold deposits were estimated down to the depth of one kilometre in the bedrock of Finland using a three-part quantitative assessment method. A grade-tonnage model was constructed for Finnish orogenic gold deposits using data from 21 known Fennoscandian and 52 known North Australian orogenic gold deposits. Eight permissive tracts were delineated for Archaean orogenic gold deposits, 13 for Palaeoproterozoic Karelian deposits and 11 for Palaeoproterozoic Svecofennian deposits.
A permissive tract does not indicate any specific favourability for the existence of deposits, just the possibility of existence. Estimates corresponding to a 50% probability, are shown plotted on each tract. The symbols do not indicate the location of the resources, they are just used to visualise the total estimated amount of undiscovered resources within each tract
The Archaean tracts cover 23,800 km2, the Karelian tracts 61,000 km2 and the Svecofennian tracts 25,000 km2. Altogether, the 32 permissive tracts cover 110,000 km2, which is 33 % of the total land area of Finland. The mean estimate of the number of undiscovered orogenic gold deposits is 18 for the Archaean tracts, 45 for the Karelian tracts and 27 for the Svecofennian tracts.
Well-known Finnish orogenic gold deposits contain 317 t of gold, which is 71 % of the total identified gold resources of 444 t in Finland. The undiscovered orogenic gold deposits are estimated to contain, at 50 % probability, at least 750 t of gold. This indicates that at least 70 % of the present total orogenic gold endowment within the uppermost one kilometre of the Finnish bedrock is in poorly explored and entirely unknown deposits.
(Last update: 20.05.2020)