(Continued)
Preparation of the skull:
Nearly a year of tireless effort went into preparing
the skull that spent so many years waiting to see the light
of day. At the Dinosaur Lab located at the University of Chicago,
fossil preparators spent countless hours cleaning and restoring
the massive skull of Sarcosuchus. Work started in
late 1999 in the lab, when Andrew Gray, a University of Chicago
undergraduate student, began his job at the DinoLab. Using
prep tools Andy spent hours in the lab cleaning away the solid
matrix around the fossil skull. From drawing the skull inside
the jacket when it was first opened to when Andy spent his
weekends working away the hard layer of sandstone, MNN 604
(the big skull of Sarcosuchus) has shown us just
how big and mean a crocodilian could actually get.
 Sediments:
As we all know, crocodilians tend to live near lakeshores
and rivers, so when they die their bodies decay and the bones
become scattered due to the water current. In the case of
MNN 604, the skull most likely was covered up quickly after
death.
Although there are some minor breaks present,
the skull remained intact. Now what sediments are in a sandy
beach? Well there are numerous minerals and other stones,
such as pebbles. The technical term for the sediment, once
it has fossilized and become hard, is sandstone (since it
is basically sand and it feels like sandpaper).
Sandstone, like any sediment, varies in hardness.
In MNN604, the sandstone was extremely hard and covered up
most of the bone in the snout region, leaving no bone surface
exposed. Sometimes the sediments tend give colors to the bone.
With MNN604, the sandstone and the bone turned a faded red
color. With no clear distinction between bone and rock, Andy
had to resort to using acetone. When the acetone is spread
over the fossil, it tends to make the bone darker and the
sediment lighter (the only setback is acetone dries too fast).
Because of its difficulty and hardness, this sediment had
to be worked down using pneumatic tools over the course of
many months.
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