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Massive Volcanic Eruptions Accompanied Dinosaur Extinction
schwit1 writes: A careful updating of the geological timeline has shown that massive volcanic eruptions aligned with the extinction event that wiped out the non-avian dinosaurs 66 million years ago (abstract). "A primeval volcanic range in western India known as the Deccan Traps, which were once three times larger than France, began its main phase of eruptions roughly 250,000 years before the Cretaceous-Paleogene, or K-Pg, extinction event, the researchers report in the journal Science. For the next 750,000 years, the volcanoes unleashed more than 1.1 million cubic kilometers (264,000 cubic miles) of lava. The main phase of eruptions comprised about 80-90 percent of the total volume of the Deccan Traps' lava flow and followed a substantially weaker first phase that began about 1 million years earlier.
The results support the idea that the Deccan Traps played a role in the K-Pg extinction, and challenge the dominant theory that a meteorite impact near present-day Chicxulub, Mexico, was the sole cause of the extinction. The researchers suggest that the Deccan Traps eruptions and the Chicxulub impact need to be considered together when studying and modeling the K-Pg extinction event."
The results support the idea that the Deccan Traps played a role in the K-Pg extinction, and challenge the dominant theory that a meteorite impact near present-day Chicxulub, Mexico, was the sole cause of the extinction. The researchers suggest that the Deccan Traps eruptions and the Chicxulub impact need to be considered together when studying and modeling the K-Pg extinction event."
This may revive the theory that the Deccan traps were formed at the antipode of a major eruption - the seismic waves will focus there, and could crack the Earth's crust (for a really big impact).
It seems logical, and the positions more or less fit, but the question was always whether the timing was viable.
Now, where is the crater that formed the Siberian traps. And, did it end the Permian period?
Not the first time I've heard this suggested. But then, given how long the dinosaurs survived, it seems intuitively that it must have taken something highly improbable - a "perfect storm" of disasters - to disrupt ecosystems enough to shift them worldwide.
The summary states that over 750,000 years the volcanoes emitted 1.1 E 6 km^2. Over that timespan it doesn't seem like much, a bit more than 1 km^2 a year. This does not seem that significant.
For instance, the Bardarbung volcano in Iceland, which erupted this year, has already produced 1 km^2 of lava, and has no sign of stopping. At that rate, for 750,000 years it would be close to the magnitude of the volcanoes in the summary. And yet the impact of Bardarbung on earthly climate is close to negligible - we are not yet extinct in any case. For an extinction event one would expect something a bit more drastic, it would seem to me.
Some info on Bardarbung here