Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: Geezer on 20/02/2010 22:11:46

Title: Would minerals have formed without life?
Post by: Geezer on 20/02/2010 22:11:46

I've heard that of the 4000 or so minerals found on Earth, more than half of them only formed as a consequence of life on Earth. Pretty amazing if it's true. Is it?

Title: Would minerals have formed without life?
Post by: JimBob on 21/02/2010 02:46:28

Ah ... er ...  I don't think this is very good info, unless you count organic crystals forms. How many organic crystals occur in nature is beyond me.

do you have a source for this pr are you drinking sheep dip again?

Title: Would minerals have formed without life?
Post by: Geezer on 21/02/2010 03:02:47

In here

http://www.scientificamerican.com/article.cfm?id=evolution-of-minerals

Title: Would minerals have formed without life?
Post by: RD on 21/02/2010 07:36:03

Quote

Remarkably, more than half of the mineral species on Earth owe their existence to life, which began transforming the planet’s geology more than two billion years ago.

http://www.scientificamerican.com/article.cfm?id=evolution-of-minerals

Not having coughed up the cash to view the full article,
I guess they are referring to limestone made from the skeletons of marine organisms,
 and metamorphic rocks derived from the limestone.

Title: Would minerals have formed without life?
Post by: Bored chemist on 21/02/2010 10:09:30

I guess oxygen in the atmosphere affects weathering of rocks too.

Title: Would minerals have formed without life?
Post by: JimBob on 22/02/2010 01:46:56

I know about aragonite (CaCO₃). It is what forms most if not all of the deposited limestone. Very little limestone is deposited by process other than biological.

But the sense I get from the short points made on the Scientific American site seems to indicate that the organisms changed the world in such a way that the formation of certain minerals was possible. If you think 'bout this, the hydrated minerals (clays, opals, etc.), many  may not have been formed without the presence of microscopic life forms that began tom chance the atmosphere by adding oxygen to it.

This process of oxygenation is most likely what they are going on about. There is a lot of limestone but the oldest limestone/dolomite I am aware of is about 800,000,000 years old. Banded Iron formations are older (~1.8 billion years old) but the debate about the origin of the BIFs is still going on. 

So, not really much news there.

Title: Would minerals have formed without life?
Post by: frethack on 22/02/2010 05:48:14

There apparently are hydrated minerals in protoplanetary disks in very young solar systems.  I read this a week or so ago:

http://www.physorg.com/news185729941.html