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Residual Placers by  Bill Anderson

This month's tip is a short and simple one. Be aware that there is a
rather rare but potentially dandy gold placer called a residual placer.
It results from precise conditions where gold exists in decomposing
bedrock.

The gold starts out, "in place" as hard-rock type gold. The
bedrock weathers or rots so to speak until it is rather earthlike.

Next to happen is gentle erosion takes the dirt away, but is not forceful
enough to remove the gold. The gold just drops to a lower horizon, but
gets concentrated now due to the fact that it is mixed with less dirt.

You must be aware that, being created in this fashion, residual placers
can be anywhere and are not limited to places where deposits would be
left by glacial movement or stream flow.

Also, the telltale gravel cobble is not necessarily there to earmark a
placer.  What gravel might be there is usually very angular or sub-
angular. Also the gold usually has a whole lot of character, not being
scrubbed down to the jellybean shape.

Residual placers are easy to miss, but that is advantage to you.

They are still there to be found.  Often though there is no gold left
under the placer in the bedrock depending if the entire hard-rock
deposit of gold weathered out.

A classic example of a residual placer is in Alaska in the Eureka
district north and west of Fairbanks. It is called Shirley Bar.  It
tossed nuggets to 7 ounces to the lucky miners.

Have fun and be safe.