Radon and radon-thoron ratios can help indicate distance of
glacial transport of radioactive material.
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Airborne and ground gamma-ray and gamma-ray spectrometer surveys find "boulder trains",
trains of radioactive material transported "down-ice" from bedrock sources.
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Boulders are commonly transported further than finer material. Also, as transport distance
increases, finer material is mixed with
other non-radioactive fine material. The radioactivity is diluted and not easily detected.
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High values of radon and
radon-thoron ratios are due to radioactivity in fine grained material
(local).
High gamma-ray values are more likely due to larger chunks and boulders (distant).
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Just west of the
Midwest Lake deposit
boulders of radioactive pegmatite are exposed on the
top of an esker. These boulders give an airborne gamma-ray anomaly that is unrelated to the
Midwest deposit and far down ice from the bedrock source.
The real boulder train, which led to the discovery,
is immediately south, "down-ice" of the Midwest deposit.
The radioactive boulders here are angular, friable and weathered, and visual
inspection reveals that they have not travelled far.
This valuable boulder train contains sufficient fine-grained radioactive material to give a
strong radon anomaly, reinforcing the conclusion that the bedrock source was not far "up-ice".
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When examining these glacial dispersion trains by
soil geochemistry, we expect that, at least
in the case of organic soils, radium would give a better indication of nearby uranium
mineralization than would uranium.
Radon in soil gas would, in turn, reflect the radium content of the soil.
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INSTRUMENTS
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We measure: radon - radium - thoron - radon daughters - alpha radiation.
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The Lucas cell is recognized as the most sensitive and reliable method for these elements.
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Our instruments are used around the world in exploration for uranium, oil & gas, groundwater and hydrothermal,
and in health physics, earthquake prediction, and evaluation of hydrocarbon and NAPL contamination.
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In the radon business since 1968, our latest major instrument update was 2011.
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Modern, low-power, field-rugged electronics.
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Sensitive to geochemical trace levels necessary for radon in lake water and for radon-thoron isotope ratios.
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Can work in a tent without electricity or be carried from point to point in the field.
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40 readings per day. Results available immediately.
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Can be operated by junior personnel if carefully supervised.
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Same instruments used for radon and radium in soil, sediment,
plant parts, rocks, water, soil gas, air, and snow, and for radon daughters in air.
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Click here for pictures of instruments.
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Click here for or other instruments, components and
assessories we provide
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For instruments contact
R.H. Morse & Associates Ltd.
1-416-269-9979
morse@finderschoice.com
skype: robert.morse.toronto
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Multilingual consulting and training (if required).
Robert H. Morse, Ph.D., P.Eng.
January 27, 2010
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