Infamous Mars meteorite contains organic molecules. But they aren't proof of life.

The question of the origins of organic molecules on Mars is not as important as the conditions that existed at the time. Liquid water and CO2 but no oxygen to provide any ozone to protect the building-block amino acids as they polymerize and form the necessary peptide and polypeptide bonds needed to become primitive proteins. The same would be true for nucleotide and oligonucleotide bonds leading to RNA/DNA. These constraints make it difficult to continue to look for life in the sediments on Mars and expect to find cellular remains. Abiotic or even carbonaceous chondrite origins would have to be ruled out.
 
no oxygen to provide any ozone to protect the building-block amino acids a



"For millions of years Mars enjoyed oceans blanketed by oxygen-rich skies and a temperate climate, whilst at the same moment Earth was a far less favourable habitat. "

 
Photooxidation ... "Our results suggest that manganese oxides could have formed abiotically on the surface in shallow waters and on continents during the Archean eon in the absence of molecular oxygen."
 
Photooxidation ... "Our results suggest that manganese oxides could have formed abiotically on the surface in shallow waters and on continents during the Archean eon in the absence of molecular oxygen."

I pressed return a little too quickly on my post above, so apologies on that... As a result I am not sure where your reply fits as I didn't give a meaningful post.

I hope further data and information is received from Mars visits....

Whether I am right or wrong to believe the position that Mars was once a water world with oxygen, time will tell... We are only able to follow what seems logical with information to hand.
I reckon I would be saddened if my position had to move to Mars just being a failed (?) planet against the measure of Earth.
 
If there was liquid water and a CO2 atmosphere, would there be evaporation, causing pressure/temp differentials, growing weather systems? And would it condense and form rivers and lakes. Would it be acid rain? What about lightening? Could the ozone have been at a much lower altitude perhaps? Has anyone estimated how long water lasted on Mars? How much of our ozone is actually created/destroyed or otherwise affected, from extraterrestrial particles at our poles? Wonder if that would change with a CO2 atmosphere.

Just ease dropping the thread and was curious. Everything seems to affect/effect everything else. Maybe only one solution will work with such a system.