Dyckman

Occurrence, Inactive

Commodities and mineralogy

Main commodities As; Mo; Zn
Other commodities Au
Ore minerals arsenopyrite; sphalerite
Gangue minerals hematite

Geographic location

Quadrangle map, 1:250,000-scale MD
Quadrangle map, 1:63,360-scale D-1
Latitude 63.838
Longitude -153.203
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is located near the summit of Dyckman Mountain at an elevation of 1,870 feet (570 m) in Section 16, T. 19 S., R. 29 E., of the Kateel River Meridian. The site is accurately located to within 100 feet (30 m).

Geologic setting

Geologic description

The Dyckman occurrence consists of disseminated arsenopyrite in an intensively altered, rhyolite volcanic (?) breccia. Extensive clay alteration has completely altered all feldspar minerals. The alteration zone was traceable for nearly 500 feet (152 m) along strike. The width of the zone is unknown. The mineral occurrence is inferred to be Cretaceous, based on isotopic age of host rhyolite (Moll and others, 1981). Two grab samples contained 350 ppm zinc and 234 ppm arsenic (Clautice and others, 1993). One sample contained 9 ppb gold (Clautice and others, 1993). DiMarchi and others (1992) report values of 1,630 ppm molybdenum and 574 ppm arsenic from limonitically stained zones in rhyolitic breccia on Dyckman Mountain.
Geologic map unit (-153.205354033569, 63.837434198638)
Age of mineralization Inferred to be Cretaceous, based on isotopic age of host rhyolite (Moll and others, 1981).
Alteration of deposit Intensive clay alteration of feldspars; chalcedonic replacements in rhyolitic breccias.

Production and reserves

Workings or exploration Two grab samples contained 350 ppm zinc and 234 ppm arsenic (Clautice and others, 1993). One sample contained 9 ppb gold (Clautice and others, 1993). DiMarchi and others (1992) report values of 1,630 ppm molybdenum and 574 ppm arsenic from limonitically stained zones in rhyolitic breccia on Dyckman Mountain.
Indication of production None
Reserve estimates None.

References