McLeod East

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Mo
Other commodities Ag; Cu; Mn; Pb; Sn; W
Ore minerals chalcopyrite; ferrimolybdite; molybdenite; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale UL
Quadrangle map, 1:63,360-scale B-1
Latitude 63.2713
Longitude -159.2698
Nearby scientific data Find additional scientific data near this location
Location and accuracy The McCleod East occurrence is at the southwestern end of the Kaiyuh Mountains, approximately 11.25 miles southeast of Blackburn, an abandoned settlement on the Yukon River. The occurrence is at an elevation of 950 feet, approximately 3400 feet south of hill 1170, in the northeast corner of sec. 6, T. 26 S., R. 3 W., Kateel River Meridian. It is approximately 2200 feet east of the caved trenches at the original McLeod prospect (UL003). The location is accurate within 500 feet.

Geologic setting

Geologic description

This occurrence consists of disseminated molybdenite in talus of quartz-veined and sericitically-altered felsic intrusive rock along the southern margin of a small stock that intrudes Cretaceous strata (Bressler and others, 1979). The strata include poorly sorted, medium- to coarse-grained arkosic sandstone and subordinate siltstone, shale, and lesser intermediate to mafic volcanic rocks. The beds generally strike northwest and dip gently to the northeast and southwest (Bressler and others, 1979). The stock is leucocratic, quartz-feldspar porphyry composed of 20-40% bipyramidal to subhedral quartz and 10-30% feldspar phenocrysts in a matrix dominantly of quartz and feldspar. The stock is exposed in an area of about 2500 by 6000 feet that is elongate to the northeast. The exposure is centered along the boundary of sections 32 and 33, and the stock sends dike swarms into sections 4 and 28 (Bressler and others, 1979).
A younger suite of biotite-quartz-feldspar porphyry dikes exposed to the west at the McLeod prospect (UL003) apparently does not occur at this site (Bressler and others, 1979).
Also see UL003 and UL004.
Geologic map unit (-159.272212988237, 63.2705971713285)
Mineral deposit model Vein and porphyry Mo (Cox and Singer, 1986; model 16a, 21b)
Mineral deposit model number 16a, 21b
Age of mineralization Cretaceous or Tertiary, the presumed age of the mineralized felsic intrusive hostrock.
Alteration of deposit The granitic stock is sericitized and locally intensely silicified.

Production and reserves

Workings or exploration This occurrence was discovered during reconnaissance mapping and sampling during 1979 (Bressler and others, 1979). No further work is documented.
Indication of production None

Additional comments

This property is on Doyon, Ltd. selected lands. For more information, contact Doyon, Ltd., in Fairbanks, Alaska.


MRDS Number A013467


Boniwell, J.B., 1981, Airborne geophysics over the McLeod prospect, Kaiyuh Mountains, Nulato, Alaska: Doyon Report 81-05, 9 p. (Report held by Doyon, Limited, Fairbanks, Alaska).
Boniwell, J.B., 1981, An addendum to the report on airborne geophysics over the McLeod prospect, Kaiyuh Mountains, Nulato, Alaska: Doyon Report 81-08, 16 sheets. (Report held by Doyon, Limited, Fairbanks, Alaska.)
Bressler, J., Cleveland, G., Ruzicka, J., 1979, 1979 annual progress report McLeod project area: Doyon Report 79-33, 48 p. (Report held by Doyon, Limited, Fairbanks, Alaska).
Lessman, J., 1979, Doyon project 1979 annual progress report: Doyon Report 79-31, 5 p. (Report held by Doyon, Limited, Fairbanks, Alaska).
Reporters S.S. Dashevsky
Last report date 8/7/2001