Glaciers reveal Martian climate has been recently active

This high-resolution image, taken by the Mars Reconnaissance Orbiter, shows the rock debris that Brown scientists believe was left by a glacier that rose at least one kilometer from the surrounding plain and... Click here for more information.

PROVIDENCE, R.I. [Brown University] - The prevailing thinking is that Mars is a planet whose active climate has been confined to the distant past. About 3.5 billion years ago, the Red Planet had extensive flowing water and then fell quiet - deadly quiet. It didn't seem the climate had changed much since.

Now, in a research article that graces the May cover of Geology, scientists at Brown University think Mars's climate has been much more dynamic than previously believed. After examining stunning high-resolution images taken last year by the Mars Reconnaissance Orbiter, the researchers have documented for the first time that ice packs at least 1 kilometer (0.6 miles) thick and perhaps 2.5 kilometers (1.6 miles) thick existed along Mars's mid-latitude belt as recently as 100 million years ago. In addition, the team believes other images tell them that glaciers flowed in localized areas in the last 10 to 100 million years - akin to the day before yesterday in Mars's geological timeline.

This evidence of recent activity means the Martian climate may change again and could bolster speculation about whether the Red Planet can, or did, support life.

"We've gone from seeing Mars as a dead planet for three-plus billion years to one that has been alive in recent times," said Jay Dickson, a research analyst in the Department of Geological Sciences at Brown and lead author of the Geology paper. "[The finding] has changed our perspective from a planet that has been dry and dead to one that is icy and active."

In fact, Dickson and his co-authors, James Head, a planetary geologist and the Louis and Elizabeth Scherck Distinguished Professor at Brown, and David Marchant, an associate professor in the Department of Earth Sciences at Boston University, believe the images show that Mars has gone through multiple Ice Ages - episodes in its recent past in which the planet's mid-latitudes were covered by glaciers that disappeared with changes in the Red Planet's obliquity, which changes the climate by altering the amount of sunlight falling on different areas.