Optimizing a Knowledge-driven Prospectivity Model for Gold Deposits Within Peräpohja Belt, Northern Finland

V. Nykänen, T. Niiranen, F. Molnár, I. Lahti, K. Korhonen, N. Cook, P. Skyttä

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

This paper combines knowledge- and data-driven prospectivity mapping approaches by using the receiver operating characteristics (ROC) spatial statistical technique to optimize the process of rescaling input datasets and the process of data integration when using a fuzzy logic prospectivity mapping method. The methodology is tested in an active mineral exploration terrain within the Paleoproterozoic Peräpohja Belt (PB) in the Northern Fennoscandian Shield, Finland. The PB comprises a greenschist to amphibolite facies, complexly deformed supracrustal sequence of variable quartzites, mafic volcanic rocks and volcaniclastic rocks, carbonate rocks, black shales, mica schists and graywackes. These formations were deposited on Archean basement and 2.44 Ga layered intrusions, during the multiple rifting of the Archean basement (2.44–1.92 Ga). Younger intrusive units in the PB comprise 2.20–2.13 Ga gabbroic sills or dikes and 1.98 Ga A-type granites. Metamorphism and complex deformation of the PB took place during the Svecofennian orogeny (1.9–1.8 Ga) and were followed by intrusions of post-orogenic granitoids (1.81–1.77 Ga). The recent mineral exploration activities have indicated several gold-bearing mineral occurrences within the PB. The Rompas Au-U mineralization is hosted within deformed and metamorphosed calc-silicate veins enclosed within mafic volcanic rocks and contains uranium-bearing zones without gold and very high-grade (>10,000 g/t Au) gold pockets with uraninite and uraninite-pyrobitumen nodules. In the vicinity of the Rompas, a magnesium skarn hosted disseminated-stockwork gold mineralization was also recognized at the Palokas-Rajapalot prospect. The exploration criteria translated into a fuzzy logic prospectivity model included data derived from regional till geochemistry (Fe, Cu, Co, Ni, Au, Te, K), high-resolution airborne geophysics (magnetic field total intensity, electromagnetic, gamma radiation), ground gravity and regional bedrock map (structures). The current exploration licenses and exploration drilling sites for gold were used to validate the knowledge-driven mineral prospectivity model.

Original languageEnglish
Pages (from-to)1-14
Number of pages14
JournalNatural Resources Research
DOIs
Publication statusAccepted/In press - Jan 10 2017

Fingerprint

gold
uraninite
mineral exploration
fuzzy mathematics
mafic rock
Archean
volcanic rock
Svecofennian orogeny
mineralization
layered intrusion
mapping method
greenschist
skarn
mineral
amphibolite facies
geophysics
carbonate rock
sill
mica
schist

Keywords

  • Finland
  • Fuzzy logic
  • Gold
  • Paleoproterozoic
  • Peräpohja Belt
  • Prospectivity
  • Receiver operating characteristics
  • Rompas
  • Uranium

ASJC Scopus subject areas

  • Environmental Science(all)

Cite this

Optimizing a Knowledge-driven Prospectivity Model for Gold Deposits Within Peräpohja Belt, Northern Finland. / Nykänen, V.; Niiranen, T.; Molnár, F.; Lahti, I.; Korhonen, K.; Cook, N.; Skyttä, P.

In: Natural Resources Research, 10.01.2017, p. 1-14.

Research output: Contribution to journalArticle

Nykänen, V. ; Niiranen, T. ; Molnár, F. ; Lahti, I. ; Korhonen, K. ; Cook, N. ; Skyttä, P. / Optimizing a Knowledge-driven Prospectivity Model for Gold Deposits Within Peräpohja Belt, Northern Finland. In: Natural Resources Research. 2017 ; pp. 1-14.
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