How to Map Placer Deposits in Streams, Creeks, & Rivers

[Roln99]

Here's an idea for mapping watercourses for prospecting. Find a creek, stream, branch, or river that you want to prospect. Before you go to your spot here are some items you'll need:

*a small water-filled balloon
*a sketching pad, colored pencils
* several feet of string (preferably cotton yarn)
*knife

When you arrive at you location first sharpen 2 sticks with your knife. Take them and place one in the ground on one side of the stream. Then tie one end of string to it. Walk across the stream to the bank directly across from the first stick. Place the other stick in the ground parallel to the first one across the bank and then tie off the string to it.

Next get you pad and colored pencils and stand in the middle of the stream on the up-stream side of the string. Now hold the pad in one hand as flat as possible and draw a rough sketch of the stream and its banks ahead of you including the string as a reference point in the drawing. Try and make this sketch a close as possible to the actual layout of the stream. If there are any boulders or other obstructions sticking out of the water be sure to include them in your drawing as well. Also add features along each bank in your drawing if possible. If you can't draw then you can take someone along with you that can.

Example


Now get the small water balloon and go back to the same spot behind the line where you initially drew the picture. Before you actually bring the balloon out with you make sure that you do a float test with it in a sink or other container full of water to make sure that it doesn't completely sink on you in the field!!! Get a different color pencil for the next phase. Now with sketch in one hand place balloon in the water centered just in front of your reference line. Let it go and then began to trace its course down the stream on the sketch.

Example


Now shade in the areas on the sketch where the new line moves away from either bank.

Example




The shaded areas are areas of top priority in the stream that you want to sample. The reason being is that current always flows in the path of least resistance. Any obstruction in the watercourse seen or unseen will repel the flow of water. these are the areas that you shaded on your sketch. So then it stands to reason that heavy placer deposits are always attracted to the path of most resistance. These obstructions in the watercourse cause pressure drops in the water's current which in turn causes heavy objects (placer material) to drop out of suspension of the water's current. These deposits then settle in the obstructions where they will remain until either found or washed further downstream by more powerful currents.

[aarthrj3811]

I hate to rain on your parade….The gold will only move with very high water. You can guess where the gold is or you can go out and take photo’s at high water. Those spots that look like low pressure areas are probably in the fast water. Those inside bends that everyone likes may not be bends at all. It will amaze you what your little stream or creek looks like at high water. You have to remember that most gold will be setting on the bedrock. It takes a lot of water force to move everything on top of the gold first..Art

[Seamuss]

I am experienced enough to read the river without all that Deparment of Fish and Wildlife experimentation to find the gold.

I'm no geologist, but I use tried and try methods of reading rivers.