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View Full Version : General geology of Grubstake, ?

10-05-2012, 10:23 PM
This is from a report that was given to us by the old timers,

The metamorphic rocks are composed mostly of mica schist, locally strongly folded. Nowhere in the Willow Creek district is the contact between the schist and quartz diorite exposed,but the schist is believed to be the oldest rock in the area and to have been intruded by the quartz diorite.
The areas formation is limited to a mica schist that is considered much older than the districts quartz diorite,(Jurassic?), within which latter formation past load gold production has been confined.
Does this mean that there were two occurrences that took place?

Geo Jim
10-06-2012, 12:12 PM
Yes, probably two different occurrences. It depends on your definition of "occurrences" is. You probably mean age of the intrusion of the golds. So I say, "yes probably."

I am more definite about the fineness of the two golds. The gold in the quartz diorite is 950, while the gold in the mica schist is 750. This suggests two different ages and kettles of molten gold down below some where.
Geo Jim