Jupiter-Mars (Damon and Pythias)

Prospect, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; As; Pb; Sb; Zn
Ore minerals arsenopyrite; boulangerite; galena; jamesonite; limonite; pyrite; scheelite; scorodite; sphalerite; stibiconite
Gangue minerals calcite; clay; quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.551
Longitude -150.8886
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Jupiter-Mars (formerly called the Damon and Pythias) prospect is in Lucky Gulch, a south-flowing tributary to Eureka Gulch. It is at an elevation of about 3050 feet, about 0.1 mile east of Lucky Gulch. The site marks the main Jupiter-Mars adit, about 0.46 mile south of the center of section 6, T. 15 S., R. 17 W., Fairbanks Meridian. The location is accurate within about 250 feet. The site corresponds to location 36 of Bundtzen (1981), approximately to the location of patented claim 32 of Hawley and Associates (1978), and occurrence 51 of Thornsberry, McKee, and Salisbury (1984).

Geologic setting

Geologic description

The country rocks in the area of the Jupiter-Mars prospect are mainly metafelsite and chloritic phyllite of the lower Paleozoic Spruce Creek sequence (Bundtzen, 1981; Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 51). The deposit is a weakly-mineralized shear zone nearly 200 feet across in metafelsite. The shear zone is nearly vertical, strikes N 60 E, and contains a body at least 10 feet thick of sheared and altered schist, mineralized and locally brecciated quartz-calcite veins, and fault gouge. The north wall of the zone is a gouge-filled fault, adjoined by a well-defined quartz-sulfide vein about 2 feet thick.
Arsenopyrite, partly oxidized to scorodite, is probably the most abundant metallic mineral in the deposit, and pyrite and galena are locally abundant. Boulangerite, scheelite, and sphalerite have been reported, and jamesonite was tentatively identified (Thornsberry, McKee, and Salisbury, 1984, v. 2; Bundtzen, 1981).
Based on several representative samples, the deposit contains a resource of 2339 tons of ore grading 0.11 ounce of gold per ton and 2.8 ounces of silver per ton (Thornsberry, McKee, and Salisbury, 1984). Representative samples contained as much as 2.9 percent lead and 11.7 percent arsenic. Selected samples assayed as much as 0.20 ounce of gold per ton and 14.6 ounces of silver per ton; these samples contained negligible amounts of base metals (Bundtzen, 1981).
In 1983, the U.S. Bureau of Mines drilled one diamond core hole. The hole is about 150 feet west of the portal of the adit and was drilled north-northwest, across the strike of the deposit. The hole encountered mineralization somewhat richer in base metals than most surface samples. A 12.4-foot intercept between 162 and 174.4 feet assayed an average of 0.052 ounce of gold per ton, 6.95 ounces of silver per ton, 8.42 percent lead, 1.2 percent zinc, and 1.85 percent arsenic. Only selected intervals of the drill core were analyzed, but all assays showed more than 0.1 percent zinc. The mineralization extends from about 28 feet to the bottom of the hole at 237 feet. Throughout this interval, the metafelsite is sheared and contains quartz-carbonate veinlets. The extent of shearing and anomalous zinc values are comparable to those at the Chloride lode (MM099), which appears to be the eastern continuation of the Jupiter-Mars deposit.
Geologic map unit (-150.890885997198, 63.5504951165845)
Mineral deposit model Low-sulfide Au-quartz (carbonate) vein, possibly grading into a polymetallic vein (Cox and Singer, 1986; models 39a and 22c?).
Mineral deposit model number 39a, 22c?
Age of mineralization The deposit is assumed to be Eocene (see record MM091).
Alteration of deposit Extensive silicification and alteration of host metafelsite. Oxidation of iron, arsenic, and antimony minerals.

Production and reserves

Workings or exploration The deposit was discovered by William Taylor, probably in the 1920s, when it was called the Damon and Pythias. A drift tunnel was driven on the vein before 1931 (Wells, 1933, p. 371). Apparently little work was done between 1931 and 1976. In 1976, Hawley and Associates (1978, fig. 4.1-A(1)-4) mapped the Jupiter-Mars workings, and conducted soil surveys on the Jupiter-Mars, Chloride (MM099), and Banjo properties (MM097). Bundtzen (1981) conducted additional mapping, and, in 1983, the U.S. Bureau of Mines drilled three diamond core holes on the Jupiter-Mars and Chloride claims (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrences 51 and 55).
Indication of production None

Additional comments

The Jupiter-Mars and adjacent Chloride claims are crossed by an east-northeast-trending shear zone that contains low-grade, gold- and silver-bearing mineralization. The claims are in Denali National Park and Preserve and are inactive.