Card Set Information
Geog 8 quiz
Principle of Orginal Horizontality
Sedimentary and Volcanic rocks are usually originally deposited horizontal layers.
if there are tilts or folds, this must have happened later, after they were laid down in a horizontal layer.
if an igneous rock fault or erosional surface cuts across a pattern of rocks those rocks must be older than the thing that cut them.
In undisturbed sedimentary or volcanic tocks, the oldest is on the bottom. Rocks pile up as they are formed.