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Re: multiple bolide impacts

> >  Granted the Deccan Traps can be attributed to the
> > pulling away of the Seychelles from India 66 million years ago, but could
> > that rift have been triggered by a bolide impact?

>Almost certainly not.
>Continental drift is driven by deep mantle convection current.

Weeeellll initially. Once rifting has been initiated, the process of sea
floor spreading is self sustaining, regardless of what the underlying
astenosphere and mantle are doing (ridge push and slab pull).

>Teeny surface pops like a meteorite impact could not really
>effect such things very much.

True, although ocean crust is brittle and once compromised will tend to
propagate any cracks, which is why ocean ridges are basically linear
features. So it might be possible for a large impact to rupture the oceanic
crust and start a rift.


cnedin@geology.adelaide.edu.au,   nedin@ediacara.org
Many say it was a mistake to come down from the trees, some say
the move out of the oceans was a bad idea. Me, I say the stiffening
of the notochord in the Cambrian was where it all went wrong,
it was all downhill from there.