Move over, Malibu - ancient Mars may take the solar system's top beachfront destination prize. It possibly had not just one ocean, but two! An older, wiser ocean, surrounding a younger version that probably knew everything about marine life and just wanted to be left alone.



The story comes from the University of Arizona, which is the first place that pops into my mind when I think of Martian marine life. These are the folks that made the 2002 discovery of water-ice near the surface throughout much of high-latitude Mars.

An international team of scientists who analyzed data from the Gamma
Ray Spectrometer onboard NASA's Mars Odyssey reports new evidence for
the controversial idea that oceans once covered about a third of
ancient Mars.

"We compared Gamma Ray Spectrometer data on potassium, thorium and
iron above and below a shoreline believed to mark an ancient ocean that
covered a third of Mars' surface, and an inner shoreline believed to
mark a younger, smaller ocean," said University of Arizona planetary
geologist James M. Dohm, who led the international investigation.

"Our investigation posed the question, Might we see a greater
concentration of these elements within the ancient shorelines because
water and rock containing the elements moved from the highlands to the
lowlands, where they eventually ponded as large water bodies?" Dohm
said.

The data suggest that the younger, inner shoreline was an ocean about 10 times
the size of the Mediterranean Sea, or about the size of North America, and
existed on the northern plains of Mars a few billion years ago. The
larger, more ancient shoreline that covered a third of Mars held an
ocean about 20 times the size of the Mediterranean, the researchers
estimate.

Scientists studying spacecraft images have a hard time confirming
"shoreline" landforms, the researchers said, because Mars shorelines
would look different from Earth's shorelines. Earth's coastal
shorelines are largely a direct result of powerful tides caused by
gravitational interaction between Earth and the moon, but Mars lacks a
sizable moon. Another difference is that lakes or seas on Mars could
have formed largely from giant debris flows and liquefied sediments.
Still another difference is that Mars oceans may have been ice-covered,
which would prevent wave action.

"The GRS adds key information to the long-standing oceans-on-Mars
controversy," Dohm said. "But the debate is likely to continue well
into the future, perhaps even when scientists can finally walk the
Martian surface with instruments in hand, with a network of smarter
spaceborne, airborne and ground-based robotic systems in their midst."

The maps are great - check them out here.