|Quadrangle map, 1:250,000-scale||MF|
|Quadrangle map, 1:63,360-scale||B-1|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The occurrence is almost at sea level on Iceberg Point, south of Jacks Cove and west of Willoughby Cove on the south-central coastline of Lemesurier Island. The site is location number 62 of Cobb (1972). It is accurately located within 0.15 mile.|
The occurrence is in limestone of Paleozoic age which, elsewhere on Lemesurier Island, is cut by granitic intrusions. The mineral suite reported at the locality: quartz, garnet, epidote, pyroxene, calcite, molybdenite, chalcopyrite, and bornite (Smith, 1942, p. 177) is a tactite suite, probably related to a nearby intrusion. An unusual asbestos-like mineral, paligorskite, called mountain leather, formed as replacement of limestone near copper-molybdenum bearing vein occurrences. Paligorskite masses reportedly were mined by Joe Ibach.The site is about three-quarters of a mile east-northeast of the Whitney claims (MF079) another occurrence of copper-molybdenum minerals on the island.
|Geologic map unit||(-136.077823541811, 58.2626507655445)|
|Mineral deposit model||Distal tactite, suspected intrusion not exposed.|
|Age of mineralization||Cretaceous or younger.|
|Alteration of deposit||Development of tactite in limestone.|
|Workings or exploration||Surface exposures of copper and molybdenum minerals were explored by trenches and cuts dug by long-time southeast Alaska prospector Joe Ibach, who occasionally lived on the island. The occurrence was first reported by Buddington (1926). It was also listed by Buddington and Chapin (1929) and briefly described by Smith (1942, p. 177).|
|Indication of production||None|
|Production notes||Production of paligorskite, probably as mineral specimens by Ibach.|
Additional commentsThe prospect is in a carbonate terrane of Paleozoic age. The prospect is in Tongass National Forest and appears to be open for mineral location. Claim activity is unknown.
Buddington, A.F., 1926, Mineral investigations in southeastern Alaska: U.S. Geological Survey Bulletin 783, p. 41-62.
Buddington, A.F., and Chapin, Theodore, 1929, Geology and mineral deposits of southeastern Alaska: U.S. Geological Survey Bulletin 800, 398 p.
Cobb, E.H., 1972, Metallic mineral resources map of the Mount Fairweather quadrangle, AK: U.S. Geological Survey Miscellaneous Field Study Map MF-436, 1 sheet, scale 1:250,000.
Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mt. Fairweather and Skagway quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-316, 123 p.
|Reporters||C.C. Hawley (Hawley Resource Group)|
|Last report date||4/14/1999|