[ RadSafe ] Radioactivity from volcanic eruptions?

[Maury Siskel]

Interesting article looks into both sides.
Best,
Maury&Dog (MaurySiskel maurysis at peoplepc.com)
___________________
http://www.talkorigins.org/faqs/ashfall.html

"... I will restrict my comments to the Chattanooga Shale since I am 
more familiar with it. While examining Mr. Froede's paper, I tried to 
keep an eye toward whether there is evidence for his hypothesis in the 
Chattanooga Shale. After studying it, however, it appears that there are 
several evidences present in the Chattanooga Shale that speak against 
his hypothesis.


Do volcanoes supply sufficient radioactive elements to equal what is 
seen in rocks?

Mr. Froede's entire thesis is that volcanic rocks contain sufficient 
primary uranium to account for the amount observed in the Chattanooga 
Shale. He states:

    Many volcanic ash deposits have been identified as containing 
significant levels of radioactive elements. Daniels (1954, p. 193-194) 
cites the collection of many volcanic ash deposits which were found to 
contain both uranium and thorium.

However when reading Daniels, we find:

    Lava and ashes, both acidic and basic, from many different volcanoes 
contain less than 1 ppm up to 11 ppm of uranium. In most cases the alpha 
counts are high enough to show that thorium is present also. The amount 
of radioactive materials given off by volcanoes is small, and it varies 
greatly with the location of the volcano and with the stage of eruption.

Daniels' data is substantiated by Zielinski (1982, p. 200), who reports 
uranium concentrations of 8 ppm in fresh, glassy, rhyolitic ash from the 
Troublesome Formation of Colorado. However, analyses of the Chattanooga 
Shale (Hickman and Lynch, 1957, p. 20) show that the average 
concentration of uranium in the Chattanooga Shale is .006 percent or 60 
ppm. From the cited references, it would appear that volcanoes are 
incapable of supplying even this low concentration of uranium, at least 
as a primary deposit. ..."

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Bjorn Cedervall wrote:

>Any comments regarding amounts and whether they can effect the background levels in any sense?
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>Perhaps some Radsafers good point at good sources of information for those of us who aren't too familiar with the topic?
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>
>Bjorn Cedervall   bcradsafers at hotmail.com
>
> 
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