basaltic rock...hmmmmmm

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chismuss
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basaltic rock...hmmmmmm

Post by chismuss » Mon Aug 07, 2017 5:22 pm

Hi All -
Have tested out my Garratt EuroAce in my permission over the weekend to "get a feel" for it as I'm a total newbie.

I especially wanted to get an idea of the soil and ground conditions, and after a frustrating morning of digging at signals with very limited results (old tool heads, plough spike and fenceposts found).....it seems that across several of the fields the underlying rocks are igneous - mainly basalt - which was confirmed both with the farmer and the available geological maps.

I got the impression (checked by digging) that the changes in the rock/soil depth were producing "results", as well as where broken clumps of rock were in deeper-soiled areas.

I am a very patient and methodical person in my work, and would like to know whether a methodical approach would pay off especially here? I am thinking that although I would hear almost constant pings in these areas, that applying more discrimination and also re-swinging from various directions/slower swings would assist in eliminating signals that were more than likely false?

Any advice from anyone who has worked similar areas would be much appreciated!

Thanks in advance! ::g

geoman
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Re: basaltic rock...hmmmmmm

Post by geoman » Tue Aug 08, 2017 12:11 pm

Which part of the country are you in ?

Basalts are high in ferromagnesium minerals and these do react with a detector. I sometimes come across cobbles of basalt and other basic igneous rocks in the areas i search which have come from the glacial tills or glacial outwash gravels. Some give a good sound ,but it is always noticable and i know what they are so rarely have to dig them.

If you are on a layer of basalt then it will give you problems. Many years ago in the days of using the Arado 120 i got permission for a field in Scotland whilst on holiday and that was undetectable with that machine because it was underlain by basalt lavas.

chismuss
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Re: basaltic rock...hmmmmmm

Post by chismuss » Tue Aug 08, 2017 2:01 pm

Hi Geoman - I am in Cornwall, lovely mix of rocks, in an area mined for lead and other metals...I'm expecting some challenges then in my little patch! x;

geoman
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Re: basaltic rock...hmmmmmm

Post by geoman » Tue Aug 08, 2017 7:58 pm

Yes you will. Galena the main ore of lead used to react on the Tesoro i used and living in cornwall you will get a lot of minerals that will affect your detector. I am sure you will get used to the challenge.
Keep us posted on how you get on.

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