The Falcon prospect, located in the Misinchinka Range, 40 kilometres northwest of the town of Mackenzie, lies in Upper Proterozoic Misinchinka Group metasediments.
The Misinchinka Group, comprised of Cambro-Proterozoic metasediments, minor volcanics and carbonates is overlain by Cambrian carbonates. North-northwest trending folds plunge to the southeast and west dipping thrusts locally repeat the sequence. A regional foliation is pronounced in less competent beds and metamorphism grades up to greenschist facies.
The Falcon prospect, a 15 to 20 metre thick iron formation of probable exhalite origin, is enclosed in mudstone, siltstone and tuffaceous sediments of the Misinchinka Group. The deposit occurs in the nose of an anticline which trends 110 to 130 degrees and plunges gently to the southeast and to the northwest. This occurrence comprises seven iron formation sub-units as follows: (1) silicate; (2) banded; (3) magnetite-rich; (4) hematite-rich; (5) chert; (6) carbonate; and (7) tuffaceous carbonate. Magnetite and hematite are associated with quartz and pyrite. Chlorite and sericite are noted in the footwall. The iron formation, probably deposited in two cycles, has reserves as follows (Assessment Report 14839):
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-UPPER FORMATION
Banded Iron Formation - 3,180,000 tonnes grading 38.7 per cent
total iron and 30.1 per cent magnetic iron.
Silica facies........ - 3,890,000 tonnes grading 29.3 per cent
total iron and 15.6 per cent magnetic iron.
-LOWER FORMATION........ - 2,010,000 tonnes grading 36.4 per cent
total iron and 23.2 per cent magnetic iron.