Article Posted on : - Jun 09, 2010

LONDON (PTI): American scientists have found further evidence that huge seas existed on Mars long ago, a discovery they say has strengthened the belief that conditions on the red planet were once favourable for the evolution of life.

A geological mapping project by researchers at the Planetary Science Institute in Tucson found sedimentary deposits in a region called ‘Hellas Planitia’ which suggests a large sea once stood there.

The 2,000 km-wide, 8km-deep Hellas basin is a giant impact crater – the largest such structure on Mars.

The researchers claimed their data support a lake between 4.5 and 3.5 billion years ago at the site, the BBC reported.

“This mapping makes geologic interpretations consistent with previous studies, and constrains the timing of these putative lakes to the early-middle Noachian period on Mars,” said Dr Leslie Bleamaster, a research scientist at the Planetary Science Institute.

According to the researchers, fine-layered outcrops around the eastern rim of Hellas are likely to be sedimentary deposits.

They were formed through the erosion and transport of rock and soil from the Martian highlands into a standing body of water.

The results support earlier studies of the western part of the Hellas basin.

However, they said that further study of the region could provide clues about where this water went and to how the Martian climate changed over geological history.

The mapping effort used data from a number of instruments aboard NASA spacecraft, including the Viking orbiter, Mars Global Surveyor and Mars Odyssey.

Some scientists believe that conditions on Mars were more favourable for the evolution of life at this time than they were on Earth.