The unearthing and collection of dinosaur fossils have not changed much over the past couple of hundred years. There are very few fantastic techniques used. Paleontologists venture out into the field armed with not much more than brushes, shovels, and a few power tools.
But, before you can stick a shovel into the ground, you have to find a fossil to excavate, which is step number one. Here’s how the excavation of dinosaur bones works.
How to Find a Fossil to Excavate
Finding dinosaur skeletons is not a case of simply digging anywhere and hoping to find a bone. Keeping teams of researchers in the field is expensive, and no institution can send teams out on a wild goose chase.
First, paleontologists start with geological maps, looking for rocks created during the Triassic, Jurassic, or Cretaceous periods of the Mesozoic Era. These were the periods when the dinosaurs roamed the earth, so these are the strata that hold the promise of a dinosaur skeleton.
Topographical maps are then used to calculate depths and see what infrastructure is nearby to support a field team.
Often, paleontologists are alerted to a skeleton by someone who sees a bone sticking out of a rock that has been weathered away.
Once a possible site has been selected, paleontologists will visit and spend a lot of time walking the area. They are looking for any evidence that a skeleton may be close by.
They are looking for weathered rocks that may reveal a fossilized bone, or they are looking for something called float. Float are small fragments of bone that have either been weathered or chipped off a more significant bone. Finding these little fragments are a pointer that a larger bone, or with luck a complete skeleton, may lie in the vicinity.
How Do Paleontologists Locate the Bone?
Researchers have tested modern technology such as ground-penetrating radar to find fossils, but the results have not been promising. So they continue using the same methods used since the first excavations were undertaken.
It takes an experienced eye to pick out a bone from surrounding rocks. To the untrained eye, they look the same, but to the eye of a trained researcher, the bone leaps out of the rock.
Fossils and rocks look remarkably similar, but bones have the same structure as when they supported a living organism. Fossilized bones have the same tiny honeycomb-like structures that living bone has.
Many paleontologists find the easiest way to tell if what they are looking at is bone or rock is to lick it. The tiny tubes in a bone will suck moisture from your tongue, but the rock will not. So, if the piece sticks to your tongue, it is a fossil, and if not, it’s a rock.
Now That You Have Found a Fossil, What’s the Next Step?
Now, you start digging!
Finding bones lying on the surface is uncommon, and often paleontologists have to remove many tons of earth and younger rocks lying on top of the layer of rock in which they are interested. Often they will use heavy machinery to remove this overburden as quickly as possible.
Once they get close to the layer of rock in which they think bones are hidden, they stop using heavy machines and swap to smaller hand tools to minimize the risk of damaging any bones.
Getting the Bone Out of the Ground
Once a bone has been found, the painstaking work of excavating it starts. Paleontologists use small picks, shovels, and brushes to excavate around the bone, taking great care not to damage the fossil in any way. This takes great patience and is precise and detailed work.
To give you some idea of how slow and painstaking the work is, many research teams will only excavate a few feet in a year! Not only are they working on getting a bone out of the rock, but they are also carefully examining everything around it.
Great care is taken during excavation as dinosaur bones may be huge, but they are very fragile, and many have cracks, which means they need meticulous handling.
Often fossils are not wholly removed from the surrounding rock before being sent back to the laboratory. Researchers fear they may be damaged in transit, so some rock is left surrounding the fossil before it is securely packaged for transport.
To protect fragile bones, research teams use “field jackets” to protect the fossil while being transported back to the laboratory. A field jacket is a plaster and burlap (hessian) cast fitted around the bone, similar to one the doctor would fit on a broken limb.
Once back in the laboratory, the field jacket is stripped away, and the preservation of the fossil can begin.
What About the Rocks Around the Fossil?
Not only is the fossil of interest, but the rock around it is also valuable as it may hold clues as to the life and death of the creature whose bones they have found.
In many cases, the rock surrounding the specimen contains evidence of other early invertebrates, mammals, and plants. They may also include tracks and coprolites, so the entire area is treated very carefully.
Buckets of the excavated pieces are carefully washed, and paleontologists sift through the washed material, looking for tiny things such as teeth, skeletons of invertebrates and snakes, or fossilized plants.
All of these little things add to the big picture of what the earth looked like in the time of the dinosaurs and what creatures and plants lived alongside these magnificent reptiles.
Science Is for Everyone
If you are interested in ancient history and are excited by dinosaurs, there are digs that you can join as an amateur. Paleontologists are keen to share their knowledge and would be happy to allow you to help on a dig.
You may sit for hours with little to show for your activity but then, to unearth something like a tooth will give you such a thrill. Sitting there under the sun, holding something that last saw the light of day millions of years ago when it was in the body of a magnificent creature, is a fabulous feeling. Nothing will ever connect you so firmly to our beautiful planet.