Mars Volcano, Earth's Dinosaurs Went Extinct About the Same Time
New NASA research reveals that the giant Martian volcano Arsia Mons produced one new lava flow at its summit every 1 to 3 million years during the final peak of activity. The last volcanic activity there ceased about 50 million years ago -- around the time of Earth's Cretaceous-Paleogene extinction, when large numbers of our planet's plant and animal species (including dinosaurs) went extinct. Read more
The arcuate fractures along the rim indicate multiple periods of activity - both eruptions and collapse after eruptions. The floor of the caldera is very flat, having been filled by lava.
Arsia Mons is the southernmost of the Tharsis volcanoes.
It is 434 km in diameter, almost 19 km high, and the summit caldera is 115 miles wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 10 km high and 120 km in diameter.
The image here is a mosaic of several daytime IR images taken by the Mars Odyssey orbiter. The indentations on the SW and NE sides align with the Pavonis Mons and Ascreaus Mons to the NE. This may indicate a large fracture/vent system was responsible for the eruptions that formed all three volcanoes.