Looking at minerals from space

Red Hand

Hello! Hope someone can help...

A friend and I were talking about the possibility of looking for mineral deposits from space and how this was actually done. I was of the opinion that one could use radar to beam back back info about rock density and that could be compared to radar samples that correalate with, say, known lead deposits. Also, if the ground or earth was exposed one could make visual confirmation from a space satallite from the characteristic colours that are produced by oxides of various metals in soils and rocks, again using lead as the example, not to mention the scarcity of vegetation in such places? I remember reading that here was diamond mine or some sort of mine discovered in the USSR because a geologist noticed a characteristic blue soil in a remote location and investigated further. In time this became one of the largest mines in the world. Could IR be used from space to find out about mineral deposits?


Wasn't radar used to discover or at least used to give a very good argument for ice on the moon, under the surface? Couldn't this be done for minerals, or is it done? I know that low flying planes and helicopters carry sonar type devices for looking for oil....is there anything used to find lead deposits?


My friend was wondering if there was any other method of looking for deposits from space other than radar. I didn't honestly know. I know of qualitative tests for lead involving destructive (ish) techniques such as mass spec, uv/vis, simple reagent tests, atomic absortion/emission, and then some not so destructive techniques such as x ray, phosphoresance, flourescence, and another type that I forget:o -but in each of these techniques, one has to be in very close physical proximty. One cannot used any type of spectrosopic instrument from space to discern lead deposits?

And one more thing-could a beam of gamma rays from a space satallite do any good in finding out about lead deposits? Aren't reactors covered in lead to protect against such rays, so theoretically they should be beamed back (a tiny portion at least) in the direction from which they were emitted from? Or is that just fantasy on my part?

What is the relationship of lead to radiation? Does it block out or return gamma rays or am I being a bit ignorant?

Thanks for reading! Hope ye can help!

tak

Could IR be used from space to find out about mineral deposits?
Seemingly yes.
http://visibleearth.nasa.gov/view_rec.php?id=15503

Aren't reactors covered in lead to protect against such rays, so theoretically they should be beamed back (a tiny portion at least) in the direction from which they were emitted from?
What is the relationship of lead to radiation? Does it block out or return gamma rays
Lead is used in nuclear reactors as an absorbing shielding, together with concrete, etc.
Sure, a tiny portion of the incident x-ray beam upon lead-bearing minerals will be (Bragg) scattered back to source by lead sulphides - but a tiny portion will be scattered back by every crystalline phase present also.
Yes, one will get characteristic x-ray fluorescence from lead on the surface if those lead minerals are exposed. But the signal received back on the orbiting satellite will be far too weak - if it ever gets through the planetary atmosphere which will absorb strongly!

As regards gamma rays. These are too strong to cause fluorescence by electron transitions but seemingly may cause nuclear reactions which in turn cause the emission of characteristic gamma radiation for different elements.
Look at
http://www.lpi.usra.edu/expmoon/Apollo16/A16_Orbital_gamma.html

Ireland has plenty of lead deposits anyway without going anywhere.
And our recycling industry is very poorly developed.
The EU RoHS Directive is there to deter the inappropriate or unnecessary use of lead and other toxic elements in most applications, barring exempted applications in the medical, energy and defence sectors.
Your buddy should be looking for gold.:)