A research team led by Brown University has found evidence of liquid water on Mars much more recently than previously reported.
The team has discovered dozens of channels carved in Mars’ most recent epoch by melted water from glaciers in the planet’s middle latitudes.
Evidence for water after the Noachian era, which ended 3.5 billion years ago, has been scant. Now, Brown University planetary geologists have documented running water that sprang from glaciers as recently as the Amazonian epoch, several hundred million years ago.
“The youthfulness is surprising,” said lead author said Caleb Fassett of Brown. “We think of [post-Noachian] Mars as really, really cold and really, really dry, so the fact that these exist, in those kinds of conditions, is changing how we view the history of water on the planet.”
The glaciofluvial valleys were created when enough sunlight reached the glaciers to melt a thin layer on the surface. This led to limited surface melting, forming channels that ran for several kilometers and could be more than 150 feet wide.
The team analyzed 15,000 images snapped by the Context Camera (CTX) aboard the Mars Reconnaissance Orbiter to compile the first survey of glaciofluvial valleys on Mars.
They found dozens of Amazonian-era ice deposits that spawned supraglacial and proglacial valleys, most of them located on the interior and exterior of craters in Mars’ midlatitude belt.
The terrain would have been very similar to the Antarctic Dry Valleys, where the surfaces of glaciers melt during the summer, sparking enough meltwater to carve a channel. The team plans to visit the region later this year to study the microclimate.
They will also search for more glaciofluvial valleys on Mars, as more images come from the CTX – which still has 60 percent of the planet left to map.