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Re: Re siberian (Deccan) traps










Ken Carpenter wrote:

Everyone's criticism of Frank's statement have all focused on his last hyperbole, rather than his criticism of the sloppy thinking behind some of the stories about impacts. One has only look at David Raup and the impact periodicity as a classic example of seeing what you want. As has been pointed out several times, there is no periodicity, even in Raup's own data. As for the Chatterjee reference, that appeared in the Proceedings of the Godwanan Dinosaur Symposium (Memoirs of the Queensland Museum, 1996). He states that either the Deccan Trap basalts are the effects of the shock wave propagating through the earth from the Chicxulub impact

If that were true, neither is relevant to extinction since Deccan volcanism began 1 Ma or so before the K-T.



OR that there was an impact in what he calls the Shiva Crater off the west coast of India. He even states that this crater is larger than the Chicxulub. How can he know the size of the crater if he isn't even sure it is one?


I understand Koeberl doubts it is. Years ago Chatterjee identified the K-T boundary in a putative impact layer (yielding iridium and shocked quartz)which he attributed to Shiva, just below the initial outpouring of lava at Bara Simla Hill. This impact layer, he wrote, dwarfed all others known, and indicated that Shiva triggered both the Deccan lava and the mass extinction. Later, however, when it became clear that dinosaurs persisted in younger, intertrappean layers, he said that Deccan volcanism and Shiva occurred by coincidence at about the same time. The K-T boundary shifted to an iridium horizon at Anjar, yet Prsad recently noted that Cretaceous fossils e.g. ostracods, occur stratigraphically above that horizon too.


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