Re: primers, and South American dinosaurs

["Jaime A. Headden" <qilongia@yahoo.com>]

Tim Donovan (uwrk2@yahoo.com) wrote:

<IIRC the Sinpetru beds are now considered early/mid Maastrichtian instead
of late Maastrichtian. I don't know if the Romanian taxa disappeared
earlier just becase the Sinpetru record terminates well before the K-T.>

  Francois Therrien has presented evidence (at the SVP meeting this year)
that suggests, via magnetostratigraphic analysis, that an early to middle
Maastrichtian age applies to the Sanpetru Formation, but this is not "now
considered to be," which is an overgeneralization. For anyone who was
there, The Sanpetru as it turns out represents a very small amount of
time, and Therrien's report of the congruence of the applied timing and of
the magnetic reversals recorded may correspond to, but do not neccessarily
apply to, such an age. This is due to the fact that the relative lengths
of the reversals only correspond to a particular portion of the
Maastrichtian, rather than clear-cut evidence it was earlier. There is no
sense of later erosion, and the population of the upper Sanpetru appears
to have been as fossiliferous as the middle and lower, so there may be
missing time. These are "suggestive," but not "telling" data.

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
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