Geoscience Reference
In-Depth Information
green fluorescent paint, the distribution of the slickensides con-
vinced Matt that the mudstones entombing the eggs did indeed
represent vertisols, which was important in understanding the ancient
climate of this site. In modern settings, vertisols form under semiarid
conditions, and we can infer that the same environmental conditions
prevailed in places where vertisols formed during ancient times.
The delicate task of uncovering the eggs took days of tedious
work. Luis, Frankie, Gerald, and other team members spent long
days under the merciless sun while gusts of wind blew grit into their
eyes. Their task was complicated by the slickensides, which had taken
a significant toll on the preservation of the eggs, often flattening them
like pancakes. Even so, we were all excited to observe this ancient
process of soil formation so intimately. Seeing eggs that had been dis-
placed a foot or so deeper from the original level of their clutch gave
us a much clearer idea of the extreme plasticity of this sediment. Nat-
urally, Matt was more excited than anyone else because soil experts
rarely have the opportunity to study extensive exposures of ancient soil
in three dimensions, much less when they are packed with dozens of
80-million-year-old dinosaur eggs.
During resting breaks at the quarry, some of us prospected in the
adjacent hills for fossilized patches of embryonic skin. Particularly
successful at this was Adrian Garrido, a young and quiet technician at
the Carmen Funes Museum (unrelated to Alberto Garrido), who
found several beautiful patches of fossilized skin in clutches near our
egg quarry. His finds were particularly important because all the skin
we had previously found was from the flats, a mile or so from our egg
quarry. Adrian's discovery indicated that the heavily cemented egg
fragments of the flats that contained the skin of unhatched sauropods
were also present around the quarry. Unfortunately, we did not have
the pleasure of having Natalia Kraiselburd, our ace collector of fos-
silized skin, on our 2000 expedition because she had taken a new job
early in the year. Adrian and others, however, picked up the slack by
finding some remarkable skin patches. Particularly productive was one
morning in which we all went to look for skin at the flats.
Lured by the beautiful specimen of the new abelisaur that we had
found the previous year, a good portion of our team, headed by
Rodolfo, spent days walking over the naked badlands of Auca Mahuevo
in search of more fossil skeletons, not an easy task under the scorch-
