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Re: Good mother dinos
> From: Tracy Monaghan <firstname.lastname@example.org>
> 1) How easy is it to distinguished eggshells pulverized by
> shells pulverized by a gazillion years of sediments?
One method that I have used, in conjunction with eggshell experts at
the Vet School in Glasgow, is to look at the crystalline ultrastructure of
the eggshell. Although this is more circumstantial, and I only use it to
distinguish between hatched and unhatched eggs, the eggshell of
hatched eggs is substantially depleted in calcite (gaps in the
crystallite structure of the shell) due to it being absorbed by the
growing embryo to help in the calcification of bone. The only problem
with this is that diagenetic fluids can produce the same effect, so the
sheel has to be looked at in context. Whethter or not the crushing of
the shell is due to the hatchling or to other animals may be difficult to
say, but it should be relatively easy to distinguish between sediment
compaction crushing and biogenic crushing.
> 2) Have dino-nests been found which contained shells more-or-less
Yes, I have a clutch of eggs with complete and intact eggs. Some of
the eggs may contain embryos. In fact I know of at least 15 eggs in
which the embryo is still inside the egg and is also complete
(although slightly disarticulated). The only problem is that I cannot
get to study them as they cost in excess of 2.5million dollars US.
Curator of Palaeontology
University of Glasgow
The first law of Geology is the law of supposition.
(Geological Howlers - ed. WDI Rolfe)