[meteorite-list] Sedimentary Martian Meteorites

[Walter Branch]

Hello Steve, Carl and List,

Thanks very much for the comments.

I am at a distinct disadvantage, not having a background in geology so 
please bear with me.

I understand exothermic processes but...

The oldest sedimentary rocks are found in various places such as Greenland, 
Hudson Bay in northern Quebec, Western Australia, etc.  These rocks are 
billions of years old, yet they are still recognized as sedimentary rocks. 
Why?  Should they not have disappeared long ago?  Would you say these rocks 
were never exposed to heat, water or weathering?

I would think that traveling through space, where obviously no terrestrial 
weathering occurs, potential Martian sedimentary rocks would not undergo 
weathering until they landed on Earth which would be on the order of 
millions of years ago. Much more recent than the oldest Earth sedimentary 
rocks.

It may very well be that the reason we don't have any Martian sedimentary 
rocks in our collections (scientific and otherwise) is because they have all 
weathered away or at least to the point where we would not recognize them as 
being Martian, or even meteoritic, in origin.

Yes, I have looked at Dr. Irving's site.

http://www.imca.cc/mars/martian-meteorites.htm

It's a great site and is on my favorites list but he doesn't speculate as to 
why we have no Martian sedimentary rocks, which is what I am most interested 
in.


-Walter