Program, Abstracts, and Guidebooks - University of Minnesota Duluth

—75—
pyrite, zinc, lead, tungsten, sand and gravel are present within
the Beardmore—Geraldton belt.
Gold and Silver
The Northern Empire Nine (near Beardmore), which began operation
in March 1934, was the first producer in the region. By
1940, 11 mines were in operation. Today, however, MacLeod—Mosher
Mines Limited, near Geraldton, is the sole producer.
The gold deposits, which contain minor silver, were classified
by Horwood (1948) into four types: 1. Simple fractures filled by
quartz veins, 2. Shear or breccia zones containLng both quartz
and sulphides, 3. Fracture zones containing quartz stringers,
and 4. Fracture zones containing massive pyrite.
Most of the gold deposits occur in metasediments of the upper
(group A or Windigokan) formation but gold mineralization is also
found in the lower metasedimencary formation, in metavolcanic rocks,
in early felsic and mafic intrusive rocks, and along the contacts
between different lithologic units,
Iron.
Iron deposits in the belt are interbedded with clastic meta—
sedimentary rocks and are composed of interlayered hematite and/
or magnetite with greywacke and argillite and, in places, jasper,
chart and iron silicates.
Sulphides
Chalcopyrite, pyrite, sphalerite, pyrrhotite, and galena
occur in fracture—filling quartz veins and in shear zones. Many
of the known occurrences are in the metavolcanic rocks north of
the Paint Lake Fault. Nolybdenite occurs near the west end of
the belt in quartz veins and is also disseminated with chalcopyrité
in altered quartz diorite Copper and nickel sulphides are associated
wicha gabbroic intrusion in Elmhirst Township.
A brecciated pyritic iron formation at least 2½ miles long
within metavolcanic rocks in Summers Township has been explored
for its sulphur contentS
Other Commodities
Ninor scheelite was recovered from the gold ores of tUe tittle
Long Lac Nine during the Second World War (Pye, 1952).
Sand and gravel deposits have been used in highway and railroad
construction.