Unnamed (near VABM Flat)

Occurrences, Inactive

Commodities and mineralogy

Main commodities Cu; Zn
Other commodities As; Bi; Mn; Sn; Sr
Ore minerals unspecified sulfides
Gangue minerals tourmaline

Geographic location

Quadrangle map, 1:250,000-scale MZ
Quadrangle map, 1:63,360-scale C-2
Latitude 65.6746
Longitude -153.921
Nearby scientific data Find additional scientific data near this location
Location and accuracy Several lode occurrences occur in an area of about one-half square mile on the southeastern flank of hill 3214 (VABM Flat), south of upper Indian River. The site corresponds to ADGGS station 92BT319 (Solie and others, 1993 [Public-Data File 93-33]). It is at an elevation of about 2,050 feet, 0.1 mile south of the center of section 8, T. 3 N., R. 24 E., Kateel River Meridian. The location is accurate.

Geologic setting

Geologic description

The rocks in the vicinity of these occurrences are Lower Cretaceous, quartz-pebble conglomerate and quartzose sandstone; andesitic and dacitic tuff, breccia, and agglomerate; and tuffaceous graywacke (Patton and others, 1977). A 7-mile-long by 1-mile-wide stock of fine- to medium-grained hornblende-biotite granodiorite is within 0.5 mile of the occurrences and thermally alters the volcanic and sedimentary rocks. Patton and others (1977) correlate the stock with the Upper Cretaceous Dulbatna Mountain pluton, dated by K-Ar at 82.3 +/-3 Ma (biotite) and 90.0 +/3 Ma (hornblende).
The Alaska Division of Geological and Geophysical Surveys collected 4 samples along the crest of a short ridge southeast of VABM Flat and 3 were submitted for trace-element analysis (Solie and others, 1993 [Public-Data File 93-33]). Samples of tourmaline veins in hornfels and of sulfide-tourmaline veins contained up to 82 parts per million (ppm) arsenic, 52 ppm bismuth, 268 ppm copper, and 1,057 ppm manganese).
Geologic map unit (-153.923591743894, 65.6740515272565)
Mineral deposit model Sn veins (Cox and Singer, 1986; model 15b), Porphyry Sn (Cox and Singer, 1986; model 20a), Sn-polymetallic veins (Cox and Singer, 1986; model 20b)
Mineral deposit model number 15b, 20a, 20b
Alteration of deposit Rocks are thermally metamorphosed ('hornfelsed'). Tourmaline veins are bordered by unspecified alteration.

Production and reserves

Workings or exploration The Alaska Division of Geological and Geophysical Surveys collected 4 rock samples along the crest of a ridge southeast of VABM Flat and 3 were submitted for trace-element analysis (Solie and others, 1993 [Public-Data File 93-33]).
Indication of production None

References