Hi Sven
I've used a petrol-powered palaeomag drill to collect samples from
sandstones. The longest core we ever managed to get was about 10 cm from a
more massive sandstone. A major problem in well-bedded sandstones is that
they tend to shear into little biscuit shaped pieces along the bedding. To
get cores longer than that the trick is holding the drill still enough so
you don't shear the core off at the base. The taller and heftier members
of the field team had more success (i.e. not me!). For over 50 cm you
might have to design some kind of rig to hold the drill still? And you'd
need longer coring bits than the standard...
The drill was petrol-powered and light enough for me to carry in a
backpack A second person had to carry the water needed to lubricate the
drill bit.
I've seen palaeoseimologists use a gadget for very long cores which
involved jumping up and down on a platform attached to the corer (again,
hefty folks required) - but that was in loose sediments.
Good luck!
Zoe
> well, it depends on the rock type and the diameter of your bit.
> standard 1 inch diameter drillbits, as used for paleomag are about 35cm
> in length. with those bits, drilling basalts all the way wouldn't be
> a problem, sediments are more tricky as well as granites and likewise
> metamorphics. anyway, a lightweight portable rock drill, running on on
> two stroke petrol should do the job. the best bits can be bought here
> <http://www.marcrist.co.uk/>. as far as engines are concerned, try
> ASC <http://www.ascscientific.com/drills.html>. alternatively, a
> lighter and perhaps ergonimically superior model can be found here
> <http://paleomagnetism.geophysik.uni-muenchen.de/images/montafon0007.AVI>.
>
> Valerian
>
> Sven Morgan wrote:
>> Does anyone have exerience using a portable rock core driller that
>> will go approximately 50 cm depth? And still be able to recover the
>> core? Deeper would be better, but 50 cm is the minimum goal.
>> The outcrop is about a mile from the road, so we need to drag the
>> equipment, but it is fairly flat terrain. I would be willing to drag
>> or roll out a generator (or have undergraduates do it).
>> thanks,
>>
>> Sven
>>
>>>
>>
>
> --
> Prof. Dr. Valerian Bachtadse
> Dept. Earth and Environmental Sciences
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> 80333 Muenchen, Germany
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