Ambler

Prospect, Probably inactive

Commodities and mineralogy

Main commodities Ag; Zn
Other commodities Au; Cu; Pb
Ore minerals galena; pyrite; silver; sphalerite
Gangue minerals calcite; quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale AR
Quadrangle map, 1:63,360-scale B-3
Latitude 67.277
Longitude -157.048
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Ambler prospect is located 2.0 miles east of Kaluriuik Creek at an elevation of 1,900 feet; in section 26, T. 22 N., R. 8 E., of the Kateel River Meridian. The location is accurate to within 500 feet.

Geologic setting

Geologic description

The Ambler prospect consists of a rhyolite dome approximately 1000 feet thick, overlain by 500 feet of layered schistose rhyolites and quartz latites, which include ignimbrites and sedimentary equivalents. The rhyolite dome footwall contact is with a calc mica schist sequence, with numerous marble and graphitic schist interbeds and thin cherty semi- to massive-sulfides. The footwall of the calc-schist unit consists of quartz-chlorite-muscovite schist, which extends for several miles to the north. The hanging wall of the rhyolite sequence consists of interbedded greenstone, calc-schist, black graphitic schist and gossanous quartz-muscovite schist. These rocks dip gently to the south and are overlain by massive greenstone and quartz-chlorite-muscovite country rock schist. At the top of the layered rhyolite sequence is a gossan vent about 40 feet thick, which has been interpreted to be an inactive degassing zone from a local fumarolic center, supported by a fragmental to vuggy rock texture and local silicification (Modroo,1983).
Mineralization consists of sulfide accumulations that are interpreted to be associated with the vent degassing area. They occur as banded base metal sulfides associated with massive chert units (Modroo, 1983).
Drill holes were completed on adjacent claims (to the south and east) by Cominco, which reported 3 to 15 feet thick silver bearing massive sulfides. Assays from an outcropping massive sulfide lens with cherty interbeds ran as high as 0.006 ounce of gold per ton, 4.96 ounces of silver per ton, 10 percent zinc, 0.78 percent lead, and 0.30 percent copper (Modroo,1983).
Geologic map unit (, )
Mineral deposit model Kuroko massive sulfide (Cox and Singer, 1986; model 28a).
Mineral deposit model number 28a
Age of mineralization Devonian, based on age of host rock (Modroo,1983).
Alteration of deposit Quartz, chlorite, calcite, and sericite alteration is associated with mineralization (Modroo, 1983).

Production and reserves

Workings or exploration Anaconda Minerals Company explored the Ambler prospect claims from 1975 to 1982; past work consisted of geologic mapping, geochemical and geophysical surveys, and 2,981 feet of diamond drilling in six holes by Anaconda Copper Company. Additional drill holes have been completed on adjacent claims (to the south and east) by Cominco, which reported 3 to 15 feet thick silver bearing massive sulfides. Assays from an outcropping massive sulfide lens with cherty interbeds ran as high as 0.006 ounce of gold per ton, 4.96 ounces of silver per ton, 10 percent zinc, 0.78 percent lead, and 0.30 percent copper (Modroo,1983).
Indication of production None

Additional comments

This record was created to give Ambler a separate record from Arctic (AR025). As of 2012, the two prospects were grouped together despite that they are separate prospects and Ambler is located 19 miles from the Arctic deposit. Both sites are in the Ambler district.

References

References

Reporters A. Angel and V.C. Zinno (Alaska Earth Sciences, Inc.)
Last report date 3/15/2016