The Terra is a gold, silver, lead, molybdenum, and copper mine located in Alaska.
About the MRDS Data:
All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.
Mine Info
Elevation:
Commodity: Gold, Silver, Lead, Molybdenum, Copper
Lat, Long: 61.7586, -153.67990
Map: View on Google Maps
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Terra MRDS details
Site Name
Primary: Terra
Commodity
Primary: Gold
Primary: Silver
Primary: Lead
Primary: Molybdenum
Primary: Copper
Secondary: Tungsten
Secondary: Arsenic
Secondary: Antimony
Location
State: Alaska
District: McGrath
Land Status
Not available
Holdings
Not available
Workings
Not available
Ownership
Not available
Production
Not available
Deposit
Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant:
Physiography
Not available
Mineral Deposit Model
Model Name: Polymetallic veins
Orebody
Not available
Structure
Not available
Alterations
Alteration Type: L
Alteration Text: Carbonate, iron-oxide, quartz, and sericite.
Rocks
Not available
Analytical Data
Not available
Materials
Ore: Arsenopyrite
Ore: Chalcopyrite
Ore: Galena
Ore: Molybdenite
Ore: Pyrite
Ore: Pyrrhotite
Ore: Tennantite
Ore: Jordanite
Ore: Gold
Gangue: Quartz
Gangue: Sericite
Comments
Comment (Exploration): Status = Active
Comment (Workings): Workings / Exploration = Reconnaissance and prospect mapping by Kennecott Exploration in the late 1990's included surface observation and sampling (Porterfield, 2000).
Comment (Deposit): Model Name = Polymetallic veins (Cox and Singer, 1986, model 22c)
Comment (Commodity): Gangue = Carbonate
Comment (Geology): Age = Cretaceous Sericite from a quartz vein in hornfels gave an Ar/Ar age date of 66.4 +/- 5.7 Ma (Porterfield, 2000).
Comment (Reference): Primary Reference = Porterfield, 2000
Comment (Geology): Geologic Description = In 1990 Allen reported anomalous gold in a rock at sample location 819 from a basal moraine at this locality. A GIS compilation and follow-up of published U.S. Geological survey mapping and sampling in the area (Allen, 1990; Allen and others 1990; Allen and Slaughter, 1990) by Kennecott Exploration led to the discovery of finely disseminated native gold and minor sulfides and sulfosalts in tectonic breccias and carbonate-quartz veins in monzonite and diorite intrusive rocks of the Hartman sequence and Jurassic or Lower Cretaceous hornfelsed sedimentary rocks of the Kahiltna terrane on the Terra property (Porterfield, 2000). Porterfield (2000) describes two target areas, each approximately 6,000 feet in length, that contain high-grade mineralization in quartz veins (as much as 687 ppm gold and 1,135 ppm silver) and carbonate-cemented tectonic breccias (as much as 71 ppm gold and 572 ppm silver) that cut intrusive rock and hornfels. Rock chip samples, talus fines, and soil samples were collected from two target areas on the Terra prospect. Gold assays have a positive correlation with arsenic, silver, antimony, copper, and lead, and Porterfield (2000) reports that bismuth and tungsten are anomalous in some samples.
References
Reference (Deposit): Allen, M.S., and Slaughter, K. E., 1990, Mineralogical data and sample locality map of nonmagnetic, heavy-mineral-concentrate samples collected from the eastern part of the Lime Hills quadrangle, Alaska: U.S. Geological Survey Open-File Report 90-67, 64 p., 1 plate, scale 1:250,000.
Reference (Deposit): Porterfield, Ben, 2000, The Terra gold prospect, Alaska Range, Alaska [abs.]: Alaska Miners Association 17th Biennial Conference on Alaska Mining, Abstracts, p. 58-63.
Reference (Deposit): Allen, M. S., Malcolm, M. J., Motooka, J. M., and Slaughter, K. E., 1990, Geologic description, chemical analyses, and sample locality map for rock samples collected from the eastern part of the Lime Hills quadrangle, Alaska: U.S. Geological Survey Open-File Report 90-69, 49 p..
Reference (Deposit): Allen, M.S, 1990, Gold anomalies and newly identified gold occurrences in the Lime Hills quadrangle, Alaska , and their association with the Hartman sequence plutons, in Goldfarb, R. J., Nash, J. T., and Stoeser, J. W., eds., Geochemical studies in Alaska by the U.S. Geological Survey, 1989: U.S. Geological Survey Bulletin 1950, p. F1-F16.
Reference (Deposit): Reed, B.L., and Elliott, R.L., 1970, Reconnaissance geologic map, analyses of bedrock and stream sediment samples, and an aeromagnetic map of parts of the southern Alaska Range: U.S. Geological Survey Open-File Report 70-217, 145 p., 1 sheet, scale 1:250,000. (Also published as U.S. Geological Survey Open-File Report 413).
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