From Gerta Keller

I am delighted to hear Kevin Pope's skepticism about the impact dust cloud scenario as primary cause for the K/T mass extinction. This scenario simply does not fit the paleontological data that show strong declines in populations for at least the last 0.5-1.0 million years prior to the K/T impact. Our recent discoveries in Mexico and Israel of three glass spherule layers in sediments spanning the last 0.5 m.y. of the Maastrichtian, and which are completely different from the spherules at the K/T boundary within the same section, suggests that multiple impacts are a more likely scenario, coupled with Deccan volcanism and the now well known rapid climate changes during that time.

Gerta Keller, Princeton University

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Gerta Keller
Department of Geosciences
Princeton University
Princeton, NJ, 08544, USA
email: gkeller@princeton.edu
phone: 609 258 4117
fax: 609 258 1671

Sounds familiar. My earlier post to E.P. Grondine.

Dan