The cross section contains evidence of folding in layer G (a squeezing of the rock due to compression- we’ll learn more about that in module 11) and faulting among the various rock layers. Explanations: A – folded rock strata cut by a thrust fault B – large intrusion (cutting through A) C – erosional angular unconformity (cutting off A & B) on which rock strata were deposited D – volcanic dyke (cutting through A, B & C) E – even younger rock strata (overlying C & D) F – normal fault (cutting through A, B, C & E).
These relations can be used to give structures a relative age. Diagram illustrating cross-cutting relations in geology.