Wednesday, June 28, 2017

Why Are Martian Volcanoes So Different From Earth's?

Why Are Martian Volcanoes So Different From Earth's?:

Shield volcanoes on Earth are so big because they are fueled by mantle plumes for many millennia. The lava that erupts is basic, unevolved and extremely fluid, which means it spreads out over long distances. Give these shields enough time, and they grow to immense sizes.
Mars is no exception, but all its shield volcanoes are far more sizeable than our own. Why is that?
Well, on Earth, our tectonic plates gradually and continuously move around, but the mantle plumes underneath them stay still. So in 100,000 years or so, Hawaii’s Kilauea will be extinct, and the baby volcano growing off its shore, Loihi, will become the primary source of volcanism in the region.
Mars, as aforementioned, doesn’t have plate tectonics, which means that the underlying mantle plumes just kept on melting rock beneath the same spot for millions of years. The shield volcanoes there got so large that if they were any more massive, they’d break the Martian crust and sink back into the mantle.

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