Earth's Top Elements
3 messages in this thread
Doug:-
A few weeks ago, I was trying to work out the amount of certain minerals in the
earth's surface, and you had given me the specific gravity of the mantle. My
computer apparently ate the file. Could you give it out again?
Hi, Bill–
Here is a copy of that older message.
–Doug
#147210 S12/Geology
25-Sep-94 19:10:18 Sb: #147021-#Earth's Top Elements Fm: Doug
Mitchell-Sysop 70621,702 To: Bill Combs 73524,2651 (X)
Hi, Bill–
Quartz and feldspars have specific gravities around 2.6-2.7, while the darker
rock-forming minerals (more iron) tend to be above 3 – somewhere in between
(say 2.8?) is my guess for the specific gravity of common igneous rocks.
Limestone would be less dense, more like 2.3. "A cubic mile of backyard dirt"
would be somewhere in this ballpark except that it includes a lot of air space.
A cubic mile of solid rock, or a specific weight of dirt might be a more
determinate starting point.
All the percentages in EofB that I looked at were specified as weight
percentages in the table headers; PPM readings may have also been by weight,
and if found in a table specifying weight percentages I would assume as much.
10.7% H and 85.7% O is clearly by weight percent. Volume percentages would
depend on what chemical combination was involved, thus I would be somewhat
surprised to see it used in such a context. Atom counts could be used, but I
would not expect them to be mixed with weight percentages unless this was made
very clear.
–Doug
Thanks for digging up that old message. You are obviously more organized than
I. It's too bad the threads scroll off after only a few days or weeks as there
is so much good data accumulated here over the months.