Friday, October 8, 2010
The oceans of Mars
New Evidence Suggests Icebergs in Frigid Oceans on Ancient Mars
Space.com: Ancient Mars once had surprisingly frigid oceans complete with their own icebergs, new evidence suggests... Researchers have found evidence of icebergs on Mars, supporting... a cold and wet Mars, governed by oceans or seas covered partly in ice, as well as glaciers and massive polar caps... [Photo evidence of past Mars icebergs here.]
Astrobiologist Alberto Fairen at the SETI Institute and NASA Ames Research Center and his colleagues suggest the presence and distribution of boulders and chains of craters could have been caused by rock fragments carried by icebergs, a common process on Earth.
They suggest glaciers in the highlands could have eroded the terrain, transporting rock within them and on their surfaces. Armadas of icebergs would have formed at the edges of glaciers as they melted and broke apart, which could then float thousands of miles on the ocean before they disappeared, depositing rock downward... In addition, when icebergs roll along the sea floor on Earth, they can generate strings of dents, perhaps explaining the chains of craters seen on the Martian lowlands.
If there were icebergs, then there were open and sizeable bodies of stable liquid water on the surface of Mars, Fairen said. 'The size of the water bodies may have ranged from several local seas to a single hemispheric ocean, and they may have been continuous in time or episodic.'
Image source here.