Publication Date:
2016-02-23
Description:
The Tiger gold deposit, located in central Yukon, Canada, has an inferred resource of 8.28 Mt containing 289,400 ounces gold at an average grade of 1.09 g/t and an indicated resource of 7.15 Mt containing 509,000 ounces gold at an average grade of 2.21 g/t. A detailed paragenetic and geochemical study of the carbonate-hosted replacement-style deposit provides constraints on the fluid history and genesis of the gold mineralizing system. The deposit is hosted in Silurian-Devonian unmetamorphosed carbonate rocks of the Mackenzie Platform and occurs 7 km northeast of the Dawson thrust, which broadly marks the northeast boundary of the Selwyn Basin. A nearby Paleocene intrusion, the Rackla pluton, subcrops ~3 km from the Tiger deposit. No other deposits of this kind have been described within the Mackenzie Platform. The Tiger deposit consists of strata-bound replacement-style mineralization adjacent to an interpreted local feeder fault. Mineralization occurs in two distinct assemblages: (1) hydrothermal dolomite, gold-bearing arsenopyrite, and minor pyrite and (2) fractures hosting native gold associated with bismuth, antimony, silver, tungsten, and minor base metals. Carbon, oxygen, and strontium isotope values suggest magmatic water, originating from the Rackla pluton, as the source of mineralizing fluids for the Tiger deposit. Microthermometric data from gold-bearing dolomites, quartz, and sphalerite document the presence of hot, ~350°C aqueous-carbonic fluids for the duration of gold mineralization, overprinted by cooler, ~150°C aqueous meteoric fluids late in the paragenesis during the waning of the mineralizing system. The Tiger deposit is thus interpreted to represent a distal expression of Paleocene magmatic activity hosted in carbonates northeast of the Selwyn Basin, central Yukon.
Print ISSN:
0361-0128
Topics:
Geosciences
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