1964 flood California

[dogbone]

I was reading about the flood laying down a second hard pack a few feet above the bedrock. Wouldn't a flood of that magnitude blow all the mud and gravel off the bedrock laying down a fresh layer of gold and sediment? Another thing I have been wondering about is a layer of river sand I have been finding fifteen feet up the bank. The first layer is dirt, then a foot down I run into a thin sand layer, then more dirt and lastly the mud layer just above the bedrock. Is this sand from the 64 flood or just sand from the old bank of a shifting river? I have also been looking for black sand on the beach checking for small gold. When the beach gets gouged out just right at a certain height there is a thin layer of black sand in between the other strata of sand. Was this also layed down from the flood?

[Sean.C]

Gravel will be removed from one area and redeposited somewhere else so new layers can form from a flood.

[dogbone]

If a 100 year flood blew all the gravel out wouldn't there just be one new layer after the flood subsided?

[FlakMagnet]

There are many kinds of "flood seams"...

There are other guys here that can give probably better information on this,

but what I have seen are flood seams that are what they called blue clay.

Many times this clay layer became a false bottom that held gold on the top of it.

There are other colors of flood seams but on the particular river I was dredging on

the good flood seam was blue clay. Sometimes if you broke through these layers,

there was very old rock underneath it which if you got through that, had great, rotted bottom.

Don't get me wrong, I did not get very rich from what I have described but I know people

who were able to spend the time it takes to understand these flood layers and

they did very well.

Ah those were good times...

Flak

[dogbone]

I guess that hard false mud layer could be so consolidated that the heavy flood would wash right over it and deposit another layer above it. So far I have only worked the banks of a river and haven't come across a false bottom or did and didn't know it. The mud layer I am fining gold in is red brown or a "baby poop" brown right above the bedrock.

[Micro Nugget]

One interesting side note regarding the '64 flood. As if that 100 year flood weren't enough, a portion of a mountain sloughed off and slid down to create a natural dam a few miles below Forks of Salmon. After the Salmon River backed up dangerously high behind this earthen barrier the Corps of Engineers used explosives to release the water before it reached disastrous levels. As a result a veritable mountain of water took out many of the bridges both on the Salmon and the Klamath. That release of water probably churned everything up all the way down to bedrock -- at least on the Salmon.

Water velocity in a river is a function of water volume in the river course, i.e., unlike a dredge which can not alter river water velocity, rainstorms, reservoir releases or sudden snowmelt events fill a fixed container [the river channel] higher than before and create a surge capable sometimes of placing most contents of the river in motion. But if the bottom is tough hardpack cemented gravels, then fast water must be capable of rolling and bouncing monster boulders along the bottom to break the hardpack up. If the rocks in the area are not terribly large, then the old layer may survive. In the desert the water surges are of brief duration, resulting in many paylayers. When drywashing gullies one can see the different layers of iron stones [as well as lighter sand layers] that major ancient floods laid down.

[dogbone]

It would be interesting to see those layers from desert flash floods. There is a layer of basketball size round rocks in the side cut of hwy 299 along the Trinity river. It is way up high above the road with the rocks jutting out from their stratification line with about twenty feet of dirt below. If this rock layer was once the bottom of the river could old gold be found just below the rocks?