Re: molten cores

On Wed, 25 Mar 2009 10:10:58 -0400, "Seth Waterston"
<sethwaterston@xxxxxxxxx> wrote:

Radioactive decay from what elements and why wouldn't those element half
lives make them non-radioactive over billions of years? Also, wouldn't the
radioactivity show up in magma reaching the surface?

The primary radioisotopes associated with internal heating are U-238
(4.47 billion year half-life), U-235 (704 million year), Th-232 (14.1
billion year), and K-40 (1.28 billion year). Given these long
half-lifes, there is plenty of remaining activity since the formation of
the material.

The estimated Earth-average bulk heating from radioactive decay in the
core, mantle, and crust is about 6e-12 watts/kg. That's a very small
amount of heat, but still plenty to account for the heating of the
Earth's core.

Although magma doesn't consist of core material at all, and only just
barely consists of mantle material, it is- like all the material making
up the Earth- radioactive. Again, the typical activity level is very
low, but that's all that is required in the case of the well insulated
core.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
.

Relevant Pages

  • Re: molten cores
    ... radioactivity show up in magma reaching the surface? ... The primary radioisotopes associated with internal heating are U-238 ... Earth's core. ...
    (sci.astro.amateur)
  • Re: OIL PRICES ABOUT TO CRASH; DRUDGE REPORT
    ... >> If the earth's core was as radioactive as its surface, ... EARTH'S natural radioactivity has been measured for the first time. ... is responsible for the immense quantity of heat generated by Earth. ... If antineutrinos are being ...
    (misc.invest.stocks)
  • Re: molten cores
    ... It is rare to find it in economically minable Uranium ores but bulk abundance is 2ppm in the crust (and likely slightly higher in the core). ... Although magma doesn't consist of core material at all, ... So, if magma did come from the core, it would have very little radioactivity anyway. ...
    (sci.astro.amateur)
  • Re: molten cores
    ... core, mantle, and crust is about 6e-12 watts/kg. ... Although magma doesn't consist of core material at all, ... magma did come from the core, it would have very little radioactivity ...
    (sci.astro.amateur)
Quantcast