|Quadrangle map, 1:250,000-scale||NM|
|Quadrangle map, 1:63,360-scale||D-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Occurrences of sulfidized rock were reported by Sainsbury, Smith, and Kachadoorian (1972) about 1.5 miles south of the confluence of Martha Creek with Tisuk River. The best occurrences were reported to be on the west side of Martha Creek. The occurrences are approximately located but probably within about a quarter of a mile of the coordinates.|
Several oxidized (limonitic?) quartz-breccia zones, as much as 100 feet across, occur in this area, especially on the west side of Martha Creek (Sainsbury, Smith, and Kachadoorian, 1972). Anomalous amounts of bismuth, copper, and lead were reported.The area is underlain by amphibolite facies graphitic metasedimentary rocks that are locally gneissic in character. Sainsbury, Smith, and Kachadoorian (1972) mapped granite stocks and felsic dikes in the Martha Creek drainage and a small tourmalinized granite about three-quarters of a mile west of these occurrences. The tourmalinized granite is at the head of a creek that parallels Martha Creek and also flows north to Tisuk River. The amphibolite facies metasedimentary rocks are now considered to have a late Proterozoic or early Paleozoic protolith (Till and Dumoulin, 1994; Hannula and others, 1995), perhaps correlative with parts of the Nome Group. Like the Nome Group, these rocks probably underwent regional blueschist facies metamorphism in the Late Jurassic or Early Cretaceous (Sainsbury, Coleman, and Kachadoorian, 1970; Forbes and others, 1984; Thurston, 1985; Armstrong and others, 1986; Hannula and McWilliams, 1995). The blueschist facies rocks were recrystallized to greenschist facies or higher metamorphic grades in conjunction with regional extension, crustal melting, and magmatism in the mid-Cretaceous (Miller and Hudson, 1991; Miller and others, 1992; Dumitru and others, 1995; Hannula and others, 1995; Hudson and Arth, 1983; Hudson, 1994; Amato and others, 1994; Amato and Wright, 1997, 1998).
|Geologic map unit||(-166.073243927609, 64.9566306291224)|
|Mineral deposit model||Quartz breccia in amphibolite facies metasedimentary rocks.|
|Age of mineralization||Cretaceous, probably related to nearby or buried tourmalinized granites.|
|Alteration of deposit||Oxidation and silicification.|
|Workings or exploration||No workings were reported; occurrences were found by Sainsbury and his coauthors Smith, and Kachadoorian (1972) during reconnaissance in 1970.|
|Indication of production||None|
Amato, J.M., and Wright, J.E., 1997, Potassic mafic magmatism in the Kigluaik gneiss dome, northern Alaska--A geochemical study of arc magmatism in an extensional tectonic setting: Journal of Geophysical Research, v. B102, no. 4, p. 8065-8084.
Amato, J.M., and Wright, J.E., 1998, Geochronologic investigations of magmatism and metamorphism within the Kigluaik Mountains gneiss dome, Seward Peninsula, Alaska, in Clough, J.G., and Larson, Frank, eds., Short Notes on Alaskan Geology 1997: Alaska Division of Geological and Geophysical Surveys Professional Report 118a, p. 1-21.
Armstrong, R.L., Harakal, J.E., Forbes, R.B., Evans, B.W., and Thurston, S.P., 1986, Rb-Sr and K-Ar study of metamorphic rocks of the Seward Peninsula and southern Brooks Range, Alaska, in Evans, B.W., and Brown, E.H., eds., Blueschists and eclogites: Geological Society of America Memoir 164, p. 184-203.
Dumitru, T.A., Miller, E.L., O'Sullivan, P.B., Amato, J.M., Hannula, K.A., Calvert, A.T., and Gans, P.B., 1995, Cretaceous to Recent extension in the Bering Strait region, Alaska: Tectonics, v. 14, p. 549-563.
Forbes, R.B., Evans, B.W., and Thurston, S.P., 1984, Regional progressive high-pressure metamorphism, Seward Peninsula, Alaska: Journal of Metamorphic Geology, v. 2, p. 43-54.
Hannula, K.A., and McWilliams, M.O., 1995, Reconsideration of the age of blueschist facies metamorphism on the Seward Peninusla, Alaska, based on phengite 40Ar/39Ar results: Journal of Metamorphic Geology, v. 13, p. 125-139.
Hannula, K.A., Miller, E.L., Dumitru, T.A., Lee, Jeffrey, and Rubin, C.M., 1995, Structural and metamorphic relations in the southwest Seward Peninsula, Alaska; Crustal extension and the unroofing of blueschists: Geological Society of America Bulletin, v. 107, p. 536-553.
Hudson, T.L., 1994, Crustal melting events in Alaska, in Plafker, G., and Berg, H. C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol. G-1, p. 657-670.
Hudson, T.L., and Arth, J. G., 1983, Tin granites of Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 94, p. 768-790.
Miller, E.L., and Hudson, T.L., 1991, Mid-Cretaceous extensional fragmentation of a Jurassic-Early Cretaceous compressional orogen, Alaska: Tectonics, v. 10, p. 781-796.
Miller, E.L., Calvert, A.T., and Little, T.A., 1992, Strain-collapsed metamorphic isograds in a sillimanite gneiss dome, Seward Peninsula, Alaska: Geology, v. 20, p. 487-490.
Sainsbury, C.L., Coleman, R.G., and Kachadoorian, Reuben, 1970, Blueschist and related greenschist faces rocks of the Seward Peninsula, Alaska, in Geological Survey research 1970: U.S. Geological Survey Professional Paper 700-B, p. B33-B42.
Sainsbury, C.L., Smith, T.E., and Kachadoorian, Reuben, 1972, Reconnaissance geologic map of the Nome D-3 quadrangle, Alaska: U.S. Geological Survey Open-File Report 72-327, 14 p., 1 sheet, scale 1:63,360.
Thurston, S.P., 1985, Structure, petrology, and metamorphic history of the Nome Group blueschist terrane, Salmon Lake area, Seward Peninsula, Alaska: Geological Society of America Bulletin, v. 96, p. 600-617.
Till, A.B., and Dumoulin, J.A, 1994, Geology of Seward Peninsula and St. Lawrence Island, in Plafker, G., and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, v. G-1, p. 141-152.
|Reporters||C.C. Hawley and Travis L. Hudson|
|Last report date||10/22/1999|