Mars_LavaFlow_031408 An image from July 19, 2005 of the Daedalia Planum on Mars reveals some of the volcanic upheavals the planet has undergone in the past. The image at left is from the Mars Express spacecraft.

The Mars Express team has recently analyzed and determined that Mars experienced violent volcanic activity on a large scale five different times in the past: covering 3.5 billion years ago, 1.5 billion years ago, 400-800 million years ago, 200 million years ago and 100 million years ago. That’s a few years ago!

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The ages of these events have been estimated by counting the number of small craters appearing on the landscape based on the theory that the older the surface, the more craters it will have had time to accumulate. The non-cratered areas may have had craters in the past but has been recently (in geological terms) been filled in or covered over by lava flows.

An interesting side-effect of the lava flows is internal heat generated by the volcanic activity which caused water to escape from the interior, creating flash flooding on a large scale. As the interior is not yet cold, scientists believe these eruptions could occur again. We have to wait to see if we can pick up any of this activity while Mars Express is in orbit. It’s mission continues at least until May 2009.

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