Unnamed (in upper Windham Bay) (ARDF #SD034) Fe

Unnamed (in upper Windham Bay)

Occurrence, Inactive

Commodities and mineralogy

Main commodities	Fe
Ore minerals	magnetite

Geographic location

Quadrangle map, 1:250,000-scale	SD
Quadrangle map, 1:63,360-scale	C-5
Latitude	57.58515
Longitude	-133.37887
Nearby scientific data	Find additional scientific data near this location
Location and accuracy	This site is located in about the middle of a ultramafic pluton about 2-square-miles in area that outcrops on both sides of the east half of the east basin of Windham Bay. The center of the body is near the northeast corner of section 33, T. 49 S., R. 75 E.

Geologic setting

Geologic description This site is a Cretaceous, Alaska-type or zoned ultramafic body that is exposed along the shoreline of upper Windham Bay (Kimble and others, 1984; Brew and Grybeck, 1984). The body is distinctly magnetic and much of it is a magnetite-rich hornblende pyroxenite. A 320-foot chip sample of the magnetite pyroxenite on the north side of Windham Bay contained 13.2 percent iron. This is lower than other similar bodies in southeastern Alaska and the body is not a viable iron resource under any reasonable economic conditions. Samples did not contain significant copper or nickel.
Geologic map unit	(-133.380579195028, 57.5848079906503)
Age of mineralization	This Alaska-type ultramafic body is Cretaceous in age.

Production and reserves

Indication of production	None
Additional comments The occurrence is in the Chuck River Wilderness Area which is closed to mineral exploration and mining.

References

References Brew, D.A., and Grybeck, Donald, 1984, Geology of the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska, in U.S. Geological Survey and U.S. Bureau of Mines, Mineral resources of the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska: U.S. Geological Survey Bulletin, 1525, p. 19-52. Kimble, A.L., Still, J.C., and Rataj, J.L., 1984, Mineral deposits and occurrences in the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska, in U.S. Geological Survey and U.S. Bureau of Mines, Mineral resources of the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska: U.S. Geological Survey Bulletin 1525, p. 105-210. U.S. Geological Survey and U.S. Bureau of Mines, 1984, Mineral resources of the Tracy Arm-Fords Terror wilderness study area and vicinity, Alaska: U.S. Geological Survey Bulletin 1525, 308 p.
Reporters	Donald Grybeck (U.S. Geological Survey)
Last report date	10/8/2004