|Quadrangle map, 1:250,000-scale||NB|
|Quadrangle map, 1:63,360-scale||D-6|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||
This placer mine is in the headwaters of Boulder Creek, a west tributary to Porcupine Creek. It is an elevation of about 3,400 feet, about 5,500 feet upstream from Porcupine Creek in the SW1/4 of section 31, T. 12 N., R. 8 E. of the Copper River Meridian. Boulder Creek is not named on the USGS Nabesna D-6 quadrangle (revised 1969), but it is identified by Richter (1966) as a west tributary to Porcupine Creek, south of Slope Creek (NB001).Richter (1964) identified Slope Creek as Boulder Creek and Cobb and Richter (1980) note that confusion between these two nearby creeks exists in several early reports. Richter's (1966) location for these creeks is followed in this records. The location shown by Richter (1966, figure 5) is just inside the Gulkana quadrangle. This is locality 59 of Richter and others (1975) who show it to be just inside the Nabesna quadrangle. The location provided by Richter and others (1975) is followed in this record and is accurate within several hundred feet. Cobb and Richter (1980) include this mine under the name 'Boulder Ck.'.
Geologic descriptionRichter (1966) and Richter and others (1975) show placer gold workings on this west tributary to Porcupine Creek. At least some of the recovered gold was coarse and smooth, but if this deposit is similar to other gold placers in the area, some of the gold may have been rough, wiry,or dendritic and it may have been associated with wiry native silver, native copper, and an unidentified bismuth mineral (Moffit, 1954; Richter, 1964; 1966). Bedrock in Boulder Creek is dominantly andesitic volcanic rocks of the upper Paleozoic, Tetelna Volcanics, but felsic plutonic rocks of the Ahtell pluton are exposed about 1 mile to the west (Richter, 1966; 1976).
|Geologic map unit||(-143.996289139238, 62.7753110848424)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a)|
|Mineral deposit model number||39a|
|Age of mineralization||Holocene.|
|Workings or exploration||Small-scale surface placer workings are present.|
|Indication of production||Yes; small|
Cobb, E.H., and Richter, D.H., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Nabesna quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-927, 117 p.
Moffit, F.H., 1954, Geology of the eastern part of the Alaska Range and adjacent area: U.S. Geological Survey Bulletin 989-D, p. 65-218.
Richter, D.H., 1964, Geology and mineral deposits of the Ahtell Creek area, Slana district, southcentral Alaska: Alaska Division of Mines and Minerals Geologic Report 6, 18 p., 1 sheet, scale 1:31,680.
Richter, D.H., 1966, Geology of the Slana district, southcentral Alaska: Alaska Division of Geological and Geophysical Surveys Geological Report 2l, 54 p., 3 sheets, scale 1:63,360.
Richter, D.H., 1976, Geologic map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-932, 1 sheet, scale 1:250,000.
|Reporters||Travis L. Hudson (Applied Geology)|
|Last report date||11/24/2002|