Geology Reference
In-Depth Information
fortnight to start myself at College which I mean joining again
from November 20th - I must get in as much time as possi-
ble to finish my Diploma course, in case I have to leave on
another job. I'm awfully keen to be back at work as I have
heaps to do. Besides a probable paper in conjunction with
Wayland on the geology of this 'ere spot, I shall work on an
independent paper as I have collected some fine rocks and
come across some very interesting geological complexes. I
intend joining the Geological Society and the Royal
Geographical Society and want the candidatures ready for the
new year's membership. Lately I have been full of ideas for
research work and shall be very keen to get started again.
One thing which has struck me in connection with earth
cooling and the condition of the earth's interior is this - and
I want to discuss it with you on my return and ask your help
in the maths involved: You know that the radium in the earth's
crust is easily sufficient to account for the radiation of heat
into space. It would be interesting to see what kind of tem-
perature gradient the corresponding amount of radium of 1500
million years ago would give. There was sea then and there-
fore the temperature of the surface
[of the Earth]
must have
been under 100 ºC
[otherwise the sea would have boiled away]
.
From rough calculations I have made out here (necessarily not
very reliable!) I estimate the Radium at 20% more
[than today]
and the temperature at 60 ºC - assuming there is exactly
enough radium for the present radiation. If that be the case
under rigid maths, it almost proves that the Earth is cold in
its interior as otherwise the earth would have notably grown
hotter.
A big problem with the discovery that radioactive elements
kept the Earth's interior hot was that if, as it was first assumed,
the elements were evenly distributed throughout the interior
then they would be generating such heat that, far from cooling
down, the Earth should be heating up. So Holmes had the clever
idea of turning around Kelvin's method of calculating the age
