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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
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
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.
Student of Geology
Northern Arizona University
Biological Science Tech
Manti-La Sal National Forest
"A _Coelophysis_ with feathers?"
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