[Date Prev][Date Next] [Chronological] [Thread] [Archive Top]

Re: [cdn-nucl-l] Very interesting but politically incorrect: " Nuclear Heart of the Earth " CNS-SP seminar [FW]



Title: " Nuclear Heart of the Earth " CNS-SP seminar [FW]

Helium is a very small molecule, and I would expect it to be quite mobile. 
There seems to be more speculations than calculations on this subject.
Has anyone calculated how long it would take this helium to diffuse out of the ground, assuming it was all formed 4.5 billion years ago?
----- Original Message -----
Sent: Wednesday, July 02, 2003 3:07 PM
Subject: RE: [cdn-nucl-l] Very interesting but politically incorrect: " Nuclear Heart of the Earth " CNS-SP seminar [FW]

An alternative explanation for high He3/He4 ratios......
 
Jaro 
 

Nature 424, 57 - 59 (03 July 2003); doi:10.1038/nature01711

http://www.nature.com/cgi-taf/DynaPage.taf?ile=/nature/journal/v424/n6944/abs/nature01711_fs.html

High 3He/4He ratios in picritic basalts from Baffin Island and the role of a mixed reservoir in mantle plumes

FINLAY M. STUART*, SOLVEIGH LASS-EVANS*†, J. GODFREY FITTON† & ROBERT M. ELLAM*

* Isotope Geosciences Unit, Scottish Universities Environmental Research Centre, East Kilbride G75 0QF, UK
† School of GeoSciences, University of Edinburgh, Edinburgh EH9 3JW, UK

Correspondence and requests for materials should be addressed to F.M.S. (f.stuart@suerc.gla.ac.uk).

The high 3He/4He ratio of volcanic rocks thought to be derived from mantle plumes is taken as evidence for the existence of a mantle reservoir that has remained largely undegassed since the Earth's accretion. The helium isotope composition of this reservoir places constraints on the origin of volatiles within the Earth and on the evolution and structure of the Earth's mantle. Here we show that olivine phenocrysts in picritic basalts presumably derived from the proto-Iceland plume at Baffin Island, Canada, have the highest magmatic 3He/4He ratios yet recorded. A strong correlation between 3He/4He and 87Sr/86Sr, 143Nd/144Nd and trace element ratios demonstrate that the 3He-rich end-member is present in basalts that are derived from large-volume melts of depleted upper-mantle rocks. This reservoir is consistent with the recharging of depleted upper-mantle rocks by small volumes of primordial volatile-rich lower-mantle material at a thermal boundary layer between convectively isolated reservoirs. The highest 3He/4He basalts from Hawaii and Iceland plot on the observed mixing trend. This indicates that a 3He-recharged depleted mantle (HRDM) reservoir may be the principal source of high 3He/4He in mantle plumes, and may explain why the helium concentration of the 'plume' component in ocean island basalts is lower than that predicted for a two-layer, steady-state model of mantle structure.

===============================================

 -----Original Message-----
From: Jerry Cuttler [mailto:jerrycuttler@rogers.com]
Sent: Wednesday June 25, 2003 2:16 PM
To: multiple (E-mail)
Subject: [cdn-nucl-l] Very interesting but politically incorrect: " Nuclear Heart of the Earth " CNS-SP seminar [FW]

The seminar was very interesting and entertaining.
 
As Dr. Marvin Herndon pointed out, there are many phenomena about the geology of the Earth that point to the possibility of a sustained, fission reaction going on, way down below, at a variable (intermittent) rate. 
 
There is significant energy still being produced (to drive volcanoes, earthquakes, continental drift, etc.) -- after 4.5 billion years.  Alpha-decay of uranium and thorium could produce this energy, which would be consistent with the helium-4 observed.  But there is a lot of helium-3 too, which could be evidence of tertiary fission, with the tritium fission product decaying to helium-3 and diffusing to the surface.  The ratio of helium-3 to helium-4 is different in different places around the globe.
 
Alpha decay would cause a slowly-changing rate of energy production, but there is evidence that the magnetic poles moved, disappeared, flipped ..., which suggests there have been rapid changes in the rate of the energy production, which is driving the generator of the Earth's magnetic field.  There is also the issue of the rate of U-235 burnup and the suggestion of significant conversion of U-238 into plutonium (breeding).  Similarly, there may be conversion of thorium into U-233 and its fission.
 
There was discussion about the other planets, especially Jupiter, which seems to be a star that didn't quite make it.  It is very distant from the Sun, yet there evidence of significant activity going on, after 4.5 billion years!  What is the source of the energy that is driving this activity?
 
The very interesting thing about all these questions/discussions is that they seem to be politically incorrect.  Dr. Herndon encounters a great deal of resistance in technical journals and from many scientists when he presents these ideas.  It seems to be sacrilegious to write or talk about the possibility of a natural nuclear (fission) reactor -- a breeder reactor no less! -- deep inside the Earth.  Part of the problem is that Dr. Herndon's knowledge of nuclear physics and nuclear reactor design is superficial, although he seems to be quite authoritative on matters of geology and seismic technology.  He would need to team up with a good nuclear physicist, but I suspect that no one wants to be openly associated with an idea that seems to be "hokey" and politically incorrect.
 
Many of the topics covered appears in Dr. Herndon's website  http://NuclearPlanet.com
 
There was a time when imaginative scientists, like George Gamov, wrote about new, far out ideas, and everyone, including good scientists, really appreciated them.  It seems that the times have changed. 
 
It's good that the CNS takes initiatives to invite brave, determined scientists to its meetings and listens to and discusses their ideas. 
 
Jerry Cuttler