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Thread: Planetology: Plate tectonics may be essential for the development of life

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  1. #8
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    Quote Originally Posted by MaeZe View Post
    Not sure I understand the difference. It's my understanding the surface cratering suggests the entire surface is the same age and not that old.
    That's because it seems to have been entirely resurfaced by a planetary-wide evulsion of magma several hundred million years ago. That stuff would have come from deep within the Venusian mantle. Earth (thank Bokonon) has never experienced that kind of planetary event, but we have had a number of "smaller" magmatic events, notably the Siberian Traps eruption about 250 million years ago that wiped out 90-95% of the living biota on the planet. That stuff doesn't come from the crust, but from much deeper. It is what is happenng right now in Hawaii. The Kilauea eruption is drawing on sub-crustal magmatic material, stuff that is melted well below the brittle crustal zone.

    You need to take my Physical Geology class. Meets Tuesday night, 6-10 PM, and Friday afternoons, 1:30-5:30 PM. There will be a mid-term exam next week. I can send you an electronic copy.

    caw
    Last edited by blacbird; 06-14-2018 at 08:13 AM. Reason: typo
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