Page 63 - Dinosaur (DK Eyewitness Books)
P. 63
THE FIND
When excavating the
bones of a dinosaur, the
paleontologists first remove
the bulk of rocks around the
bones. Then they clear away
the matrix (rocky material
immediately surrounding the
bones) as much as possible
using hammers and chisels.
Next they encase the bones
in jackets made of sackcloth
soaked in wet plaster. This
sets hard quickly, forming a
strong, rigid coat. Each plaster CLEANING A LIMB BONE MAKING A PLASTER CAST PREPARING FOR STUDY
jacket protects the fragile 1A paleontologist carefully brushes 2The paleontologists apply runny 3The dinosaur bone arrives at a
fossil bone inside against away dirt from a big, fragile dinosaur plaster of Paris to sackcloth bandages. laboratory still wrapped in its plaster
damage on the ride to a limb bone. The goal is to clean the They wrap these around the bone and cast. Technicians remove the cast so
laboratory for proper study. fossil before encasing it in plaster. wait for the plaster to set hard. the bone can be studied.
TOOLS OF THE TRADE
Paleontologists use tools like these to free fossils stuck in rock,
to clean them, and to pack them safely for later examination.
They might paint fragile bones with watery glue to stop them
from crumbling, and then encase the bones in a jacket. They
make one kind of jacket by dipping an open-weave fabric into
a paste made of water mixed with powdered plaster of Paris. Or
they might wrap the bones in aluminum foil and then pour on
chemicals producing polyurethane foam, which expands and
covers the fossils to protect them.
Polyurethane
Hard foam jacket
paintbrush
for clearing
away dust
while rock is Aluminum
chipped away
foil covers fossil
Club
hammer Glue for hardening
for driving an exposed fossil
chisels into
the rock
Soft
paintbrush
for cleaning
the exposed
fossil more
intricately
Roll of plasterer’s
cloth (open-
weave fabric)
and plaster
of Paris
