Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: paul.fr on 20/08/2007 16:26:56

Title: minerals to rocks, rocks to soil, but how?
Post by: paul.fr on 20/08/2007 16:26:56

i hear that minerals will eventually become rocks, which inturn become soil. but how?

Title: minerals to rocks, rocks to soil, but how?
Post by: Bass on 20/08/2007 17:05:55

minerals + heat and pressure = rocks
rocks + erosion = soils

Title: minerals to rocks, rocks to soil, but how?
Post by: pete_inthehills on 21/08/2007 12:49:31

I like to think of this not as two seperate equations, but one big cyclical one.

rocks + erosion + organic matter = soil; soil + heat + pressure = rocks; rocks + erosion....round and round and round

pete
inthehills

Title: minerals to rocks, rocks to soil, but how?
Post by: _Stefan_ on 21/08/2007 13:39:46

Can rock be formed by pressure without heat? Like the different layers of soil and rock you find as you dig deep deep down?

Title: minerals to rocks, rocks to soil, but how?
Post by: eric l on 21/08/2007 14:32:41

Quote from: _Stefan_ on 21/08/2007 13:39:46

Can rock be formed by pressure without heat? Like the different layers of soil and rock you find as you dig deep deep down?

I remember being shown formations consisting of a kind of natural concrete. 
Wikipedia has an article on such agglomerates :  http://en.wikipedia.org/wiki/Clastic_rock

Title: minerals to rocks, rocks to soil, but how?
Post by: pete_inthehills on 21/08/2007 22:14:40

often the pressure comes from burial and that causes heat as well, but I do remember something about pressure alone causing minerals to bond.  It was something like pressure melting or some such.  And there is the usual biological/chemical factors.  Oolites are a good example.  A grain of sand rolls around on a lime mud sea floor, gets a coating of lime mud and they eventually chemically bond to make an oolite.  So yeah, you don't need heat, but they often work together.

pete
inthehills