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Re: extinction in China




Zhao's principal motivation was to strengthen the case for continuous deposition during the K-T interval in the Nanxiong basin. Most researchers, e.g. Russell, maintain
that the Nanxiong (or Pingling) - Shanghu contact is disconformable, an opinion apparently based at least partly on the lack of an iridium anomaly there.<
Lack of iridium across the boundary can be explained by reworking of the iridium, if you are indeed getting constant deposition. Similar situations are not common, but do occur across the KT Boundary.


Does it support a specific alternative? It is interesting that Mikhailov suggested the Macroolithus egg type was laid by T. bataar, inasmuch as it is the largest of the elongatoolithid eggs of presumed theropod
affinities, and abundant, like T. bataar, in the Nemegt svita e.g. at Tsagan Khushu.<
Or a therizinosaur, which has also been suggested. Unless you have an embryo, or a parent on the nest, you can't say for certain what laid those eggs. And, as for disappearance, as HP Irmis brought up onlist a week or two ago, disappearance from the fossil record is not entirely equivelent to the extinction of an organism.


The Nanxiong record may be relevant to global extinction in that it demonstrates Tyrannosaurus radiated into paleoenvironments where it did not belong c. 65 Ma, with devastating results.<
Until you can prove that the eggs were laid by a tyrannosaur, and that there was overpredation in the fossil record, then this hypothesis is untestable.
Peace,
Rob



Student of Geology Northern Arizona University Biological Science Tech Manti-La Sal National Forest AIM: TarryAGoat http://www.geocities.com/elvisimposter/dinopics.html http://www.cafepress.com/RobsDinos "A _Coelophysis_ with feathers?"

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