Use sonar to find fossils.

[Ultermarto]

Would using sonar by pounding vibrations into the ground and drawing an image with the echo be a viable way of fossil hunting? I guess not, since we're not doing it. It's just that the idea crossed my mind a while ago, and now I'm watching Jurassic Park and they're doing it too. It's too good an idea if both me and Spielberg have it!

 

Anyway I know this must be grounded in some fundamental misunderstanding of sonar or something. But it's killing me. I mean the fossil record is so scarce, fossils are so hard to find, and here's this phony-balony solution that keeps slapping me over the head.

[swansont]

I suspect the problem is one of resolution. You need short wavelength waves to be able to see structure, and these have to be able to penetrate and interact with the fossil. But the frequency may not be one that travels well, and there's an issue of reflecting off of layer boundaries, which will be abundant in sedimentary rock.

 

Sound is used for larger-scale investigation, like finding fossil fuels, at much lower frequencies.

[Enthalpy]

I've recently seen images from a sea sonar with cm resolution. This sonar operates at 1MHz, and consequently, has very few meters range. The range and image sharpness must be worse in soil, because soil is less homogenous than seawater.

 

An other reason is that a fossil is a stone like an other. Sometimes a flat print on a stone, sometimes a 3D organ or organism turned into stone, but its acoustic properties must differ little from the surrounding soil, so the fossil will not be obvious. The human eye should be the best analyzer for the sonar images.

 

If you want to try it:

- The sonar having a limited range, I feel important that its transducers can be moved quickly. Though, near 1MHz, an excellent contact is mandatory. This point needs attention.

- Signal processing can help you. Not to recognize a fossil, but to remove echoes from the surface, deep layers... This is well developed (at lower frequencies and longer ranges) for oil and gas exploration.

- It could be easier over the bed of the Ocean or a lake. Sound transfer from a moveable transducer is easier there.

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Got 8 million hits (and nice pictures) with the searchwords

sonar archaeology

but these side-scan sonars picture only the seabed and the objects on it, they don't penetrate the underlying soil.