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Basics Of Ground Penetrating Radar


Alex_Sor

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Winter work through the ice.

This is a picture of a real bed of an old river, under a layer of ice.

(Ice is radio-transparent)

Now there is a swamp in that place, but we were looking for the old river bed.

the first channel of river - on the green scale (top of the image) 50-200,

the second channel of river= 650-800.

810705820__viber_2020-12-15_18-50-24.thumb.jpg.ceb336d61f5e1de1bd70aefbf1031f6c.jpg

Measurements were made across the river bed!

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What a great thread! Chalk me up as another person fascinated with what a prospector could do with GPR.

Like Steve, I am curious about searching for paleo river channels, buried and lost under sediment, except I am curious about searching for them in Nevada where the soil is quite salty.

I see from your chart that salt attenuates the radio waves quite a lot. What sort of depth might a person expect from your GPR in salty/alkaline soils? Does this attenuation decrease when the soil is dry versus wet, when the salt ions are not as mobile, and if so, how much more depth might be expected when the salty soil is dry?

Do you have any units in the US to demonstrate in the field?

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Dear sirs 🙂
1) dry salty (even just salt itself) soils break through well (low attenuation). Any crystalline rocks break through well, we can talk about 5-15 meters of depth. Wet (wet) salt rocks are electrolyte (like seawater) and have a very high attenuation.
2) America (USA) has made it almost impossible to visit with tourist visas, all of us (who live in the former USSR, Ukraine) are considered criminals and deceivers 🙂 who will come and stay to live illegally in the USA. If someone took responsibility and made an invitation to one of us, we could bring a radar and travel (visit) places (fields) for measurements.
3) The cost of a radar complete with all antennas is about $8000. You could chip in money (put together money from several people) and buy one radar for several people, we could send you a radar and support you remotely.
4) Gold mining means you spend hundreds of thousands of dollars on digging and flushing equipment. If you do not have equipment for deep exploration (for example, georadar), then you will spend tens of thousands of dollars on fuel and blindly washing tons of rock, playing roulette - "lucky or unlucky." In Ukraine, many amber seekers have georadars, despite the fact that we are a poor country and for such a sum of money you can buy a house in a village in Ukraine  🙂
 
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We found some data on Republic of Ghana (Africa)

An expedition to search for gold placers worked there in 2014.

They were looking for the channels of ancient rivers in order to check the placers of metals. Unfortunately, we were not given the primary files of georadar surveys, we received only a part of the reports ...

The reports were verified during the expedition by excavator digging. The shooting depth actually reached 12-14 meters. A radar with a frequency of 300 MHz was used.

I will give below what we have.

1) the test object buried in the soil of Ghana looks like this:

333.thumb.png.9643e67ed4569e73acce9cb59db372ce.png

The soil is mineralized and "rings" around the object.

2) This is how a layer of pebbles (boulders of different sizes from granite) looks like on the radar screen.

grav.thumb.png.c228fb220da592ee7b5a05fcc14506dc.png

 

3) this is what a raft looks like with splashes of metal.

You see numerous V-shaped and inverted V marks at the bottom (deep).

plot.thumb.jpg.74a05925c58b24b572fd2fce8759cb8e.jpg

plot1.thumb.jpg.263d5e900624a57115f3ee6788046e0d.jpg

 

4) here is the combined frame: on the left is what the radar shows, and on the right is the result of a hole cut by an excavator.

 

plot0.thumb.jpg.878f38173865d76239df3df71bf9dab3.jpg

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