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Re: Scientists conclude asteroid, not volcanoes, wiped out dinosaurs



 How do we know how abrupt were the extinctions?   Were they really
 all that abrupt?

Their duration lies at or below the resolution of the most detailed stratigraphic sections; that's called "geologically instantaneous" because it can't be distinguished from an instantaneous event.

In contrast, the Deccan traps were pumped out over a span of at least 4 million years; the main episode ended 100,000 years before the boundary.

 Were the Deccan trap eruptions like the Siberian traps, or were they
 just a series of super volcanoes?

The former.

 Volcanic winter didn't cause that rapid a die off.

Flood basalt eruptions (effusive volcanism) don't cause volcanic winters. Explosive volcanism does that -- but explosive volcanism is something else.

 Also, don't flood basalt volcanoes put out iridium?

The Deccan basalt contains one of the lowest amounts of iridium ever measured for any rock (0.1 ppb). It follows that the iridium in the global boundary layer comes from big-E Elsewhere.