Professor Bill Mahaney is part of an international group of scientists that analyzed data from the Gamma Ray Spectrometer (GRS) aboard NASA's Mars Odyssey orbiter. The spectrometer has the unique ability to detect elements as much as a third of a meter below Mars’ surface.

The data showed areas of enriched potassium, thorium, and iron, which scientists believe mark the shorelines of two ancient oceans that existed at different stages of the planet’s evolution. The younger shoreline, on the northern plains of Mars, is estimated to have been about ten times the size of the Mediterranean, and existed a few billion years ago. The larger, more ancient shoreline encompassed an ocean 20 times the size of the Mediterranean, researchers estimate.

“Results from Mars Odyssey and other spacecraft suggest that past watery conditions likely leached, transported and concentrated these elements,” says University of Arizona planetary geologist James M. Dohm, who led the investigation.

Mahaney, who teaches physical geography at York, focused on geochemical analysis, looking for signs of weathering of rocks and minerals, and the presence of paleosols – ancient soils that provide insight into the climate of the early Martian environment.

“The concept of oceans on Mars has been controversial, so this is very exciting,” Mahaney says. “We believe this data provides significant insight into the atmosphere-surface interactions during the early evolutionary stages of the Red Planet.”

Scientific debate on the existence of ancient Martian oceans was sparked by several studies going back almost 20 years. One such study hypothesized that erupting magma unleashed massive flooding, which pooled in the northern lowlands of Mars, forming seas and lakes that triggered relatively warmer and wetter conditions, lasting tens of thousands – or perhaps even millions – of years.

Scientists are driven to understand how and when water existed on Mars in order to further their understanding of whether the planet’s environment has been favourable for microbial life.

”The GRS data highlights the presence of large concentrations of iron, a necessary prerequisite for microbe respiration and evolution,” Mahaney says.

Dohm notes the Mars-oceans controversy is far from over. “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 space-borne, airborne and ground-based robotic systems in their midst."

The findings will be published in a special edition of Planetary and Space Science. Co-authors include scientists from Italy, Spain, and South Korea, along with Canada and the US. Mahaney is the sole Canadian contributor.
 

Media contact:
Melissa Hughes, Media Relations, York University: 416 736 2100 x22097, mehughes@yorku.ca

York University is the leading interdisciplinary research and teaching university in Canada. York offers a modern, academic experience at the undergraduate and graduate level in Toronto, Canada’s most international city. The third largest university in the country, York is host to a dynamic academic community of 50,000 students and 7,000 faculty and staff, as well as more than 200,000 alumni worldwide. York’s 11 faculties and 26 research centres conduct ambitious, groundbreaking research that is interdisciplinary, cutting across traditional academic boundaries. This distinctive and collaborative approach is preparing students for the future and bringing fresh insights and solutions to real-world challenges. York University is an autonomous, not-for-profit corporation.

-30-