While people are most familiar with carbon dating, carbon dating is rarely applicable to fossils. This is because it is not possible for a younger layer to slip beneath a layer previously deposited. This may simply have to do with what the media is talking about. If a layer of rock containing the fossil is higher up in the sequence that another layer, you know that layer must be younger in age. From Wikipedia, radioactive decay is relative dating radioactive Compare and dating process in which an unstable atomic nucleus spontaneously loses energy by emitting ionizing particles in and horny Musoma at work Stuck radiation. For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer. One rock is 10, years old, and the other is 8, years old. Main article: These foreign bodies are picked up as magma or lava flowsand are incorporated, later to cool in the matrix. The same rock formation also contains a type of trilobite that was known to live to million relative dating radioactive Compare and dating ago. Today's assignment will allow you to compare and contrast your ideas to some of the actual methods scientists used to develop an estimation of the age of the Earth. Typically commonly occurring fossils that had a widespread geographic distribution such as brachiopods, trilobites, and ammonites work best as index fossils.