What You Really Need to Know About Tertiary Channels (Part 3)
(Tertiary rock that clearly indicates evidence of geologic "folding" and uplift over time.)
Okay, I think I've spoken enough about how the dream merchants out there play up "ancient rivers of gold" to feather their own nests with your money. Now I want to talk to you about the three main aspects of gold-bearing Tertiary Channels you need to know.
1) Gold in Tertiaries
I had to smile a bit when my Idaho mining buddy Gary described Tertiary river channels "as dried up old riverbeds." This they are for the most part, but Tertiaries are millions of years old and they carried placer gold at a time when gold mining was only a glimmer in the Creator's eye.
Gold Panning Kits
Gary also asked about what sort of gold values Tertiaries carry. This is a great question that can be answered pretty simply. Depending on where they are and the distinct characteristics of how ancient deposition took place, Tertiary Channels can run the gamut as far as their gold-bearing potential is concerned.
Just as Fickle
Some of the richest Tertiaries in the entire world were found in the northern end of California's Motherlode Region, particularly around Nevada City and points north. Hundreds of thousands (if not millions) of troy ounces of placer gold were recovered from these ancient riverbeds (often called the Great Blue Lead), including many large nuggets as well as smaller nuggets, coarse pieces, large and small flakes, and the usual fine gold.
(Ancient river gravels exposed in a hillside cut in Nevada. Note the beginnings of a "drift" tunnel at the base of the cut.)
However, before you begin salivating at the prospect of all that gold you need to understand that this "richness" was relative...some sections of California's Tertiaries carried little placer gold while other sections carried only fine or flour gold. In other words, Tertiary paystreaks could be just as fickle as those in many modern day auriferous streams.
I think this is one of the basic misconceptions many small-scale placer miners have about Tertiary Channels...that is, that any and all Tertiaries are money in the bank just waiting to be withdrawn. It's not that easy my friends, sad to say.
Here's the plus side though. If you were to locate a good gold-bearing Tertiary section somewhere and had the means and gear to work it, then brothers and sisters you would be working true "virgin ground," something that's nearly extinct these days, particularly here in the U.S.
But you're not home free yet. In my next post I'll be talking about the difficulties and the dangers involved in working Tertiary Channels.
You didn't really think it was going to be that easy did you? Take care until next time.
If you liked this post, you may want to read: "Basic Characteristics of Canadian Placers and Placer Gold"
(c) Jim Rocha (J.R.) 2012
Questions? E-mail me at firstname.lastname@example.org