Identify a Fossil and Its Age
According to the Merriam Webster's dictionary, a fossil is "a remnant, impression, or trace of an organism of past geological age that has been preserved in the earth's crust." Those who identify and date fossils are called paleontologists. Paleontologists study fossils to identify and learn about life in past geological time. Geologists also use fossils to determine the age of rock formations in which the fossil was found. A fossil can either be fauna, meaning animal, and/or flora, meaning plant.
Instructions
Excavation and Age Determination
1. A fossil may have to be excavated from the earth or rock formation. In order to retrieve the fossil, you must first remove it from its location. You may need a shovel or a trawl to remove the fossil. Flora can be identified by its pattern. They can be ribbed and scaly or have a distinct leaf pattern. Fauna fossil remains usually resemble the original organism. For instance, if the fossil is the remains of a shell-dwelling animal, it will have a distinctive curl pattern that is moderately or particularly ribbed.
2. Fossils generally are composed of remnants of the original organism; usually it is only the hard parts of fauna, which have not had time to decompose before they were encased in rock. Fossils can become fragile once the hard dirt or rock is removed and is exposed to the air, so it is important to use smaller tools, such as a sturdy brush or smaller trawl. Some paleontologists and archaeologist will use toothbrushes and dental instruments to clean away the fine sediment from fossils. Flora is usually found embedded in rock because they were covered in sediment before they had time to rot. These rocks are often small and portable with no need for further excavation.
3. There are two ways to determine a fossil's age: relative dating and absolute dating. Relative dating is determined on how old other fossils or rocks are that were found in the same sediment layer. Absolute dating is determined on similar fossils already discovered and dated. Absolute dating requires a carbon 14-test, in which a small portion of the fossil is analyzed for its carbon percentage. All living things contain the same amount of carbon-14. After the organism dies, the remains lose carbon-14 at a steady rate. Scientists measure the amount of carbon-14 left and by using the steady rate ratio, calculate the amount of time that has passed.
Tags: amount carbon-14, before they, dating determined, fossil remains, Identify Fossil, original organism
