Blocks of hydrocarbon ice might be floating on the surface of existing lakes and seas of liquid hydrocarbon on Saturn's moon Titan, U.S. researchers say.

The presence of ice floes could explain some of the mixed readings the Cassini spacecraft has seen in the reflectivity of the surfaces of lakes on Titan, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Tuesday.

Titan is the only other body besides Earth in our solar system with stable bodies of liquid on its surface, although in the case of Titan its lakes of and seas of hydrocarbons like ethane and methane rather than water.

Ethane and methane are organic molecules often considered building blocks for the more complex chemistry from which life arose.

"One of the most intriguing questions about these lakes and seas is whether they might host an exotic form of life," Jonathan Lunine, a Cassini scientist at Cornell University, said. "And the formation of floating hydrocarbon ice will provide an opportunity for interesting chemistry along the boundary between liquid and solid, a boundary that may have been important in the origin of terrestrial life."

Cassini has observed a vast network of hydrocarbon seas in Titan's northern hemisphere while a more widely-spaced set of lakes adorn the southern hemisphere, JPL said.