Unnamed (southeast of upper Finger Glacier) (ARDF #MF009) Fe, Ti

Unnamed (southeast of upper Finger Glacier)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Fe; Ti
Other commodities	Cu; Pb; Sn
Ore minerals	ilmenite; magnetite; unknown sulfide phases

Geographic location

Quadrangle map, 1:250,000-scale	MF
Quadrangle map, 1:63,360-scale	C-4
Latitude	58.502
Longitude	-137.068
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	The occurrence is about 4.2 miles northwest of Mt. Marchainville on a ridge southeast of upper Finger Glacier at an elevation of about 6000 feet. The location is estimated from the location of sample number 44 of Rossman (1963). It is approximately correct based on the 6000-foot elevation; by latitude and longitude, the location is in the adjacent B-4 quadrangle. It is probably accurate to about 0.25 mile. The location in Kimball and others (1978) is uncertain.

Geologic setting

Geologic description The ilmenite-magnetite occurrence at Rossman's (1963, B 1121-F) location number 44 is within and about 1.4 miles from the southwest contact of the Crillon-LaPerouse layered mafic-ultramafic intrusion (Brew and others, 1978). Layering in the stock near this locality strikes northwest and dips moderately steeply to the northeast. At the locality, ilmenite and magnetite are concentrated in cumulus layers. Analysis of a heavy-mineral concentrate (Rossman, 1963, table 7) by semiquantitative spectrographic methods found between 10 - 100 percent iron and 1 - 10 percent titanium. Heavy-mineral concentrates also contained 0.1 - 1 percent each of copper, lead, and tin and 0.01 - 0.1 percent of cobalt and nickel. The concentrations of the trace metals are sufficiently low that they do not prove separate mineral phases for any of the trace metals.
Geologic map unit	(-137.069912868621, 58.5016343093173)
Mineral deposit model	Possibly Bushveld Fe-Ti-V (Cox and Singer, 1986; model 3?). Ilmenite and magnetite enriched in cumulus layers of a synorogenic (Foley and others, 1997) layered mafic-ultramafic stock.
Mineral deposit model number	3?
Age of mineralization	Tertiary.

Production and reserves

Workings or exploration	Surface outcrops only; no development.
Indication of production	None
Reserve estimates	No reserves projected. Thickness and horizontal continuity information lacking.
Additional comments Chugach terrane. The site is in Glacier Bay National Park and Preserve.

References

MRDS Number	A013134
References Brew, D.A., Johnson, B.R., Grybeck, D., Griscom, A., Barnes, D.F., Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources of the Glacier Bay National Monument Wilderness Study Area, Alaska: U.S. Geological Survey Open-File Report 78-494, 670 p., 7 sheets. Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: U.S. Geological Survey Bulletin 1693, 379 p. Foley, J.Y., Light, T.D., Nelson, S.W., and Harris, R.A., 1997, Mineral occurrences associated with mafic-ultramafic and related alkaline complexes in Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 396-449. Kimball, A.L., Still, J.C., and Rataj, J.L., 1978, Mineral resources, in Brew, D. A., and others, Mineral resources of the Glacier Bay National Monument wilderness study area, Alaska: U.S. Geological Survey Open-File Report 78-494, p. C1-C375. Rossman, Darwin, 1963, Geology and petrology of two stocks of layered gabbro in the Fairweather Range, Alaska: U.S. Geological Survey Bulletin 1121-F, p. F1-F50.
Reporters	C.C. Hawley (Hawley Resource Group)
Last report date	4/5/1999