By:Daniel J. Peppe(Department the Geology, Baylor University)&Alan L. Deino(Berkeley Geochronology Center)©2013stclairdrake.net Education


You are watching: Why is it difficult to assign a numerical age to a sedimentary rock?

*

Citation:Peppe,D.J.&Deino,A.L.(2013)Dating Rocks and Fossils making use of Geologic Methods.stclairdrake.net education Knowledge4(10):1
*

*

*

*



See more: What Is The Closest Ocean Beach To Ohio Than Myrtle Beach? You Have Options

Using relative and also radiometric dating methods, geologists space able to answer the question: how old is this fossil?

Despite seeming like a reasonably stable place, the Earth"s surface ar has changed dramatically end the past 4.6 billion years. Mountains have been built and also eroded, continents and oceans have moved good distances, and also the earth has fluctuated native being very cold and also almost totally covered v ice to being really warm and also ice-free. These alters typically take place so gradually that they are barely detectable end the expectations of a person life, yet even at this instant, the Earth"s surface ar is moving and also changing. As these alters have occurred, organisms have actually evolved, and remnants that some have been preserved as fossils.

A fossil have the right to be learned to recognize what sort of biology it represents, how the organism lived, and also how it was preserved. However, by itself a fossil has actually little an interpretation unless it is inserted within some context. The age of the fossil need to be established so it can be contrasted to various other fossil species from the exact same time period. Knowledge the eras of related fossil species helps scientists piece together the evolutionary background of a team of organisms.

For example, based on the primate fossil record, scientists understand that life primates evolved from fossil primates and that this evolutionary history took 10s of millions of years. By comparing fossils of various primate species, scientists can examine exactly how features adjusted and just how primates evolved through time. However, the age of every fossil primate demands to be figured out so the fossils of the exact same age uncovered in various parts the the world and fossils of various ages have the right to be compared.

There room three basic approaches that allow scientists to date geological materials and answer the question: "How old is this fossil?" First, the relative period of a fossil have the right to be determined. Relative dating put geologic events in chronological order there is no requiring the a details numerical period be assigned to each event. Second, it is possible to recognize the numerical period for fossils or planet materials. Numerical periods estimate the date of a geological event and can occasionally reveal quite precisely when a fossil varieties existed in time. Third, magnetism in rocks have the right to be provided to calculation the age of a fossil site. This method uses the orientation that the Earth"s magnetic field, which has readjusted through time, come determine periods for fossils and also rocks.