Rock Positions-- Law of Superposition
Superposition...oldest deeper
Fossils and Superposition
Unconformities
Cross Cutting Diagrams Intrusions like the red magma must be igneous to cut
through the existing sedimentary layers. Faults break up some layers only.
Youngest
Oldest
Unconformities
If sedimentation is interrupted, erosion may occur before new sediment is laid down. The gap in the rock layers is called an unconformity.
Dikes
A dike is an intrusion of some other rock material that pushes through the existing rock. Here is a basalt dike in sandstone