Where Does It Come From?

In search for the source of all that gold

What Was the Source of the Tertiary Gold?

Books

Nice decomposed vein of highly mineralized quartz. This one I'm going to pursue.

If you're a gold miner you have a natural curiousity about all things gold. If you're like me you've found yourself looking up at the canyon walls and wondering where all the gold in the river came from.

We know the overwhelming amount of gold in California came from the old tertiary channels; but where did that gold come from? Somewhere out there is the "Mother Lode."

the old miners, and geologists spent a lot of time trying to answer that question. If you believe Vladimir Lundgren, the state geologist in the late 1800's, it didn't come from far.

The theory goes the tertiary channels ran for thousands of miles, but the geologists know only after they passed over enrichment zones would they pick up significant amounts of gold. I've often had these discussions with other miners and each has his own theory. I've heard some say the gold came from as far away as Alaska, but the geologists say the tertiary rivers ran from the south to the north.

I was once talking with a hard rock miner who'd spent considerable time thinking about this. We were standing in an old hydraulic pit filled with white quartz, some the size of small cars. He pointed to the next ridgeline to the north and said it came from over there.

His theory was the existing lode sources enriched the tertiary rivers. At first this sounded pretty far-fetched, but the more prospecting I did, and the more thinking I did I began to conclude he was right. The gold really did come from a short distance away.

Not being a geologist I have to refer back to what the geologists of the Gold Rush era believed, and they had studied this problem for quite some time, and importantly, they present evidence for it.

There isn't a singular "mother lode". There are belts of mother lodes which were eroded away over millions of years causing some rivers, gulches and streams to become highly enriched. The dead rivers eroded these belts and picked up considerable gold. This gold was then deposited in today's rivers when they cut the old channels.

Certainly some of today's gold is picked up from current eroding lode sources, but the geologists agree the vast majority of California gold is from the action of the tertiary channels. Finding these belts is finding the source.

I've spent a fair amount of time chasing down these old lode sources. Not necessarily the old mines, but the mines are a very good indicator of the belts, you can just look at where lode mines are clustered. By and large I've found they tend to run northwest - southeast in direction following fault lines.

I've concluded these lode sources are just about everywhere you look. The challenge becomes finding the ones which will pay. As a hardrock miner told me one time you can't tell if a quartz vein has gold in it by looking at, you have to sample it, crush it and assay it. The geology books from the 1800s contend virtually every quartz vein in the Mother Lode carries gold.

I'm looking for gold, but along the way I'm looking for what would be the gold-bearing veins. The quartz veins. They're everywhere, the challenge is finding the good ones. The indicator of gold bearing veins is highly mineralized ground.

The below picture is of a really nice mineralized vein I found last summer. I traced the vein at least 3,000 feet above the ground and it runs straight vertical down. There is a old mine portal below it about 400' which seems like a long way down the vein if you ask me, but it also tells me the vein runs at least 400' vertical from the surface, and then who knows how much further under ground.

This vein isn't isolated or unique, it is, however, bigger and longer than other veins I've come across.

Each year I find myself dedicating more and more time to chasing down the quartz veins. At first it was a day or two and mainly just attempts to find some high grade in the tailings. Then I began to wonder what the vein looked like. This led to looking for other veins in the same area to where now I'm spending a lot of time chasing lode sources.

Whether the tertiary channels picked up their gold from these lode sources or not I don't know. The amount of quartz in the tertiary gravels suggests they excavated out some enormous quartz veins. I would like to find the veins that the tertiary channels cut but some geologists say there is more quartz in the tertiary channels than could possibly come from all the quartz veins in California, so the channles either cut veins which no longer exist, or they brought a lot of quartz in with them.

If you read the historic references you begin to narrow your search down. There are clear lines where the tertiary channels became enriched. These lines are the likely lode sources for the placer gold and would be a good place to start your search.

The gold and the veins are still out there. A few years back I ran into a hard rock miner who had discovered a completely new lode source just a couple hundred feet off a main road. It was in an area known for lode, he just went where others didn't go and found high grade embedded right in the vein showing above the ground. No one bothered to look there in 150 years.

The next discovery could be yours.

Rock Hammer

Close up of mineralized quartz vein