Definition of relative dating
Relative age dating also means paying attention to crosscutting relationships.Say for example that a volcanic dike, or a fault, cuts across several sedimentary layers, or maybe through another volcanic rock type.For example, which is older, the bricks in a building or the building itself?Are there repairs or cracks in the sidewalk that came after the sidewalk was built?
Take students on a neighborhood walk and see what you can observe about age dates around you.
Look for “absolute” ages such as cornerstones, dates carved into fresh concrete, or dates stamped on manhole covers.
Absolute age dating: Have students work alone or in pairs to find an article or paper that uses radiometric age dating.
The most obvious feature of sedimentary rock is its layering.
This feature is produced by changes in deposition over time.