Your goal is to study the smooth, parallel layers of rock to learn how the land built up over geologic time.Now imagine that you come upon a formation like this: What do you think of it? How can you make any conclusions about rock layers that make such a crazy arrangement?Before radiometric dating it was difficult to determine the actual age of an object.Radiometric dating, based on known rates of decay of radioactive isotopes in objects, allows a specific age of an object to be determined to some degree of accuracy.Relative dating is a scientific process of evaluation used to determine the relative order of past events, but does not determine the absolute age of an object.Long Answer: Sciences such as geology, paleontology and archeology are very interested in identifying the age of objects found and these scientists sometimes use either relative dating or absolute dating to characterize the age of the objects they study.According to the law of superposition, as long as an area remains undeformed by outside forces, the deeper you go down through the layers of rock, the older they are.So, if you know the ages of the layers in the parent and wall rocks, you can calculate the age of the layers in your subsided area or xenolith by matching them.
Numerical dating determines the actual ages of rocks through the study of radioactive decay.Igneous rocks form from eruptions of lava or magma.Metamorphic rock is formed by great pressure far below the Earth's surface.The primary difference is that absolute dating assigns an actual time or age to an event or object.
Relative dating simply says one is older than the other but no age is specified.Layers of volcanic ash are igneous deposits, while layers of rock these deposits surround are usually sedimentary. Igneous intrusions form when magma breaks through a layer of rock from beneath, or lava flows down from above. When igneous intrusion causes newer sedimentary layers to sink into older ones, it's called subsidence.