4 How it worksLayers of rock are called strata. Once the order of the formation of rocks is known, the relative age of the rocks can be determinedRelative age indicates that any one layer is older or younger than another layer, NOT THE EXACT AGE OF THE ROCK!
5 Law of SuperpositionAn undeformed sedimentary rock layer is older than the layers above it and younger than the layers below it.If the layers aren’t horizontal then the law is not easily applied, then scientists need to find clues:1.) particle size2.) shape of bedding plane3.) ripple marks
7 Uh oh, unconformitiesAre a break in the geologic record due to erosion or faulting.3 types of unconformities are :1.) nonconformity – stratified rests on unstratified rock2.) angular – the boundary between tilted and horizontal layers3.) disconformity – boundary between layers of rock that have not been deposited continuously