Scientists scratching heads over 'cookie' landform on Mars

NASA researchers are puzzled by a "giant cookie" that has been spotted on the surface of Mars.

The circular landform is 2km in diameter and rises up like an island surrounded by a smooth plain of lava flows.

It is located in the Athabasca region of Mars, and NASA researchers speculate volcanoes played a role in its creation.

It is believed lava could have pushed up underneath the planet's surface, evaporating or melting ice in the mount to create the distinctive ravines in the chocolate wheaten-style "cookie".

NASA scientists said there were a number of other land features in the region that were similarly puzzling.

They hope closer examination will allow them to solve the mystery of how the landforms were made - or at least find out who has been dropping giant cookies all over the red planet.

The cookie crater is not the only interesting formation to catch the eye of interplanetary observers.

On the same theme, an impact crater on Mercury appears to resemble popular Sesame Street character Cookie Monster.

The famous Galle crater on Mars is iconic for its "smiley face" appearance.