It’s been known or at least theorized in recent years that Mars isn’t really geologically dead like the moon. It just seems to be in slow motion compared to Earth. Valles Marineris is now thought to be the result of plate tectonics. It’s still not active enough to produce volcanos however. Mons Olympus and the Tharsis plateau is most likely the result of the asteroid impact that created Hellas Planitia on the opposite side of the planet billions of years ago. Much like how the asteroid that wiped out the dinosaurs 66 million years ago may have created huge volcanos at the same time in the area which is now India.
Much like how the asteroid that wiped out the dinosaurs 66 million years ago may have created huge volcanos at the same time in the area which is now India.
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The Deccan traps, nearly antipodal Chicxulub crater, created 66 mya ; eruptions lasted est. 30,000 years ; lava flows of basalt covered 600,000 square miles ; 6,500 feet deep; volume 122,750 cubic miles ; due to the volume of gases it was likely was another cause of the Dino die-off.
Another impactor also hit at near the same time off India’s coast : the 310 mile wide Shiva crater.
Note : basalt eruptions are like the the eruptions on the Hawaiian Island Chain, not the explosive sort like St Helens.