A new American research has revealed that an ancient "riverbed" in Mars was not made by the flow of water but was carved by molten lava.

The 270-km long Martian channel near the Ascraeus Mons volcano does not seem to have been made by water.

"We started seeing that, instead of this [liquid] cutting into an existing surface, it was building a surface-it built a ridge up to 40 meters [130 feet] high" millions of years ago, explained study co-author Jacob Bleacher of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

The channel is also roofed over in some areas and lined with vents, characterises usually linked to lava tubes.

Bleacher said: "You don't see this on Earth in [river] settings.

"But you see it all the time in volcanic settings. So that's kind of our smoking gun."

However, Bleacher, who presented his work last week at the 41st Lunar and Planetary Science Conference, said this does not mean water never existed on the red planet.

But it does mean scientists may have to reconsider when and where they believe water might have existed on Mars.

According to Laszlo Kestay, a planetary geologist on the NASA team that produced the new images of the channel, the findings are also exciting because they shed new light on Mars' volcanic history.

"I think there are some very clearly water-formed features on Mars, but there are other things that are more puzzling. Jake and colleagues make a very compelling case that at least this one is volcanic," National Geographic News quoted Kestay, as saying.

And chances are bright that other channels in the Ascraeus Mons area will turn out to be lava-made as well, said Kestay, who works with the U.S. Geological Survey's Astrogeology Science Center.

According to him, the new image data are "revealing not just these channels but a whole suite of smaller volcanic features and showing that volcanism is more widespread spatially than people hought." (ANI)