Think about the gas released as a result of fracking shale. Compare this energy resource to the conventional resources we have been using throughout the last one-hundred and fifty years. Using the model seen here, compare the age of the coal we have been using to the gas produced by the fracked Marcellus shale. A) Coal formations are much younger than the shale. B) Coal and shale formations are about the same age. C) The shale is younger than the coal formations we use today. D) Scientists cannot determine which layer is older than the other.
The answer is A because coal formations are much younger than the shale. If we use the law of superposition, we can predict the relative age of each. The coal, closer to Earth's surface, is younger than the deeper shale.
