used by scientists involved with fossils
Let's pretend we're paleontologists, with our very own dig and equipment. Fossils are millions of years old, and so, as you can imagine, they must be handled with care! They also have to be properly marked and analysed.This page deals with the procedures we must go through to make sure that our fossil remains intact, and is well documented.
Finding and Extracting the Fossil
1. Positioning by means of a grid
A grid is used to record the exact location of your find. This is very important for research and to give clues to the origin of the fossil later. The area of the site that is partially exposed is divided up into squares formed by strings tied to pegs. The area of each is one yard square. A wooden frame, one yard square and divided into 100 squares, is moved along the string grid and the exact position of each fossil is recorded.
2. Chipping and Chopping
We need a variety of hand axes, spades, chisels, hammers and brushes, and a small sieve or strainer for smaller finds. Use the hammers to chip away rock, but be patient, and always change to a finer tool if you think you're getting close. A fine brush, such as a shaving brush,is used to brush away dust on your rock. For small fossils, rather chip out a large chunk of rock around it, and do the fine work at home.
Transporting the Fossil
1. Stabilizing, Strengthening
Fine fossils in flaky stone are often stabilized by painting them with a resin or glue. It prevents them from drying out and decaying, as well as mends small breakages. Paint the surface, then leave it to dry, before you remove it from its base.
2. Plaster Cast
This method of protection is used for large fossils. The exposed area of the fossil is first covered with wet tissue paper, then with layers of strips of material soaked in Plaster of Paris. Be careful that the weight of the specimen does not cause it to crack when its dry.
3. The Moving
Small fossils should be packed in newspaper and into a box. Larger specimens should be transported in a wheelbarrow to the vehicle. Extremely large fossils are hoisted out using pullies and chains.
Cleaning and Analysing the Fossil
Small fossils need only be rinsed off with clean water. Larger fossils, however, need more care. Firstly, the plaster of Paris must be cut away. Be careful not to damage the specimen. Point the tool away from the fossil in case you slip.
2. Acid decomposition
One can extract fossils by imersing them in suitable acids. The acid dissolves a portion of the rock away. When a piece of the fossil is visible, an acid-resistant hardener (glue) is applied over the exposed area and the sample is put back into the acid. This process is repeated until the whole fossil is exposed. The fossil is washed to remove excess acids and glue. This is a slow but very safe method as the fossils aren't damaged by mechanical tools.
3. Radiocarbon Dating
Scientists use carbon dating to try and get an accurate estimate of how old the fossils are. This method involves measuring the changes that occur at constant rates in the atomic structure of substances. The dating measures the amount of the radioactive carbon isotope, carbon-14 in organic matter. In dead animals (ie fossils) the amount declines at a constant rate after death, and thus the age of fossils up to 50,000 years can be determined.
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