Large as it is I think that this crater might not have been the only cause of the Permian extinction. I am inclined to think there may be a very major crater buried under the Siberian lava flows. I base this conjecture on the following:
Recent studies by Chattergee (sp?) in India point to the existence of the Shiva Crater and the edge of the Deccan Traps, about 200 by 400 miles and the same age (65 my) as the Yucatan (dinosaur) crater. This would be the same general mass as the propoposed Antarctic impactor and only killed 70% of life forms.
The Chesapeake Meteor (35 mya) was 50 miles in diameter, and the Popigai (Siberia) crater 60 miles wide, and the Toms River crater, 9 miles wide, all falling about the same time killed less than 50% of life.
As we saw during the recent Jupiter bombardment, boloids come in families.
I wonder if the Siberian traps are contrecoup damage to the Antarctic strike.
Anyone happen to know the relative locations 250 mya?
As an aside, the Chixchulub strike was a shallow water strike. Much more deadly than a dry land strike. Sea water poured into the white-hot crater and flashed to steam, it's the recipe for poached planet.
From: Astrobio.net;
At the time of the K−T extinction, India was an island located over the Reunion hotspot. Hotspots are fixed points where hot material from the mantle rises to the Earth's surface. This underground welling flooded portions of India with a vast amount of lava. Today, these cooled lava fields are called the Deccan Traps.
The slow outpouring of Deccan lava probably began a few million years before the K−T extinction. Then about 65 million years ago, the trickle became a torrent.
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They don't buy the idea of a "Shiva Crater" but seem to associate an acceleration of activity in the Deccan Traps to the the Chicxulub event. It may be that a large impactor might effect volcanism at distant locations. The Antarctica impactor may have caused increased volcanism at the P-Tr boundary in the location of the Siberian Traps. Where was the Hawaiian Hotspot 250mya?