The Circle Mining District is an area in the North Central region of Alaska. Approximately 100 miles NorthEast of Fairbanks. The area has been historically mined since the late 1890's.
1998 Circle Mining District Annual Picnic Photos and info.
The district has both historical and active placer gold production with over one million ounces produced. The area has potential for the discovery of both high-grade gold in quartz veins similar to the new discovery at Pogo and low-grade in quartz stockwork zones similar to the nearby Fort Knox mine. The project area has not been systematically explored for hard rock mineral deposits.
Geology: The geology of the Circle district consists of metamorphosed Paleozoic sediments that are bounded on the north by the major Tintina fault zone and intruded by several granite phases. These rocks are part of the Yukon Tanana upland terrain that hosts several major gold deposits, including the Fort Knox and Pogo gold deposits.
The intrusive rocks found in the district are Cretaceous and Tertiary granite and granodiorite that occur as stocks and dikes. These intrusive rocks are elongated in an east-west and north-northwesterly direction and are centered on a regional anticline structure. The 90 million-year-old granodiorite and granite intrusives are likely candidates for the source of gold mineralization in the district. The 54 million-year-old Tertiary granite also has gold mineralization associated with it, even though its age suggests it to be less productive. Historic placer production usually terminates where these intrusives are exposed in the upper reaches of the drainages. Recorded placer gold production from at least 20 drainages is just over one million ounces. Lode mineralization in the district occurs as gold-arsenopyrite-quartz veins and stock works in massive, micaceous quartzite and schist near both the intrusive contacts and within the granitic rocks. No lode production is recorded from the district.
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