Presentation on theme: "A Lesson on Dating Geologic. How old is old? How do you date a rock? Absolute Dating –Analogous to your age... i.e. an exact number –Often found using."— Presentation transcript:
A Lesson on Dating Geologic
How old is old?
How do you date a rock? Absolute Dating –Analogous to your age... i.e. an exact number –Often found using the radioactive decay of certain elements Relative Dating –Dating with regard to an order of events... analogous to knowing that you are the middle child –Found by examining the local geology and discovering what happened before and after
Who would want to date a rock?
Three simple rules for dating rocks: Law of Original Horizontality –i.e. if you dump out a bunch of sand, it wont stack up vertically... Law of Cross-Cutting Relationships –In order to cut something, something has to be there before you cut it Law of Superposition –If you are making a sandwich, you cant put the top on first...