RE: Our problems are over!.

["Jim Otton" <jkotton@usgs.gov>]

Kjell, Radsafers,

A standard reference for uranium-series information in natural systems is:

Ivanovich, M., and Harmon, R.S., eds., 1992, Uranium-series disequilibrium:

applications to earth, marine, and environmental sciences (second edition):

Clarendon Press, Oxford, 910 pages



Coral dating is done using U-234-Th-230 dating with the U and Th measured by

either alpha counting or mass spec.  Results and discussion of coral dating

are given in several papers in the above reference.  Corals in these papers

are in the 2-4 ppm U range.



Sea water uranium concentration is essentially constant at 3.3 ppb with a

U-234/238 activity ratio of 1.14 (Osmond and Cowart- p. 310 in the above

book, citing Ku and others (1977) and Chen and others (1986)).



Jim Otton

Energy Program

U.S. Geological Survey







-----Original Message-----

From: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]On Behalf Of Johansen, Kjell

Sent: Monday, March 10, 2003 6:57 AM

To: Radsafe (E-mail)

Subject: Re: Our problems are over!.





I do not remember what the U-234/U-238 is in sea water, but U forms

complexes with Ca seawater, which explains the association with coral

calcium.  Element like Th and Pr precipitate out of the water column because

they do not form complexes.  Their removal is aided by phytoplanktonic fecal

pellets and the rain of dead minute organisms to the ocean floor, so of

which dissolve along the way.  The coral can be dated by looking at the

radial distribution of various radionuclides and radionuclide ratios.  I do

not remember which because it has been quite a while since I have kept up

with the radiometric dating literature.



standard disclaimers apply.



Kjell Johansen

Point Beach Nuclear Plant

Two Rivers, WI

kjell.johansen@nmcco.com

************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/





************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/