Particularly useful are index fossils, geographically widespread fossils that evolved rapidly through time.
Sediments less than about 50,000 years old that contain organic material can be dated based on the radioactive decay of the isotope Carbon 14.When you have completed the practice exam, a green submit button will appear. You can skip questions if you would like and come back to them later with the "Go To First Skipped Question" button.When you have completed the practice exam, a green submit button will appear. You will lose your work if you close or refresh this page. If a geologist claims to be 45 years old, that is an absolute age.Superposition: The most basic concept used in relative dating is the law of superposition.Many sections of the Wasatch fault disturb or crosscut the Provo shoreline, showing that faulting occurred after the lake dropped below this shoreline which formed about 13,500 years ago.As this example illustrates determining the age of a geologic feature or rock requires the use of both absolute and relative dating techniques.Choose your answers to the questions and click 'Next' to see the next set of questions.You can skip questions if you would like and come back to them later with the yellow "Go To First Skipped Question" button. Choose your answers to the questions and click 'Next' to see the next question.Simply stated, each bed in a sequence of sedimentary rocks (or layered volcanic rocks) is younger than the bed below it and older than the bed above it.This law follows two basic assumptions: (1) the beds were originally deposited near horizontal, and (2) the beds were not overturned after their deposition.