Cross-cutting relationships

It was first developed by Danish geological pioneer Nicholas Steno in Dissertationis prodromus (1669) and later formulated by James Hutton in Theory of the Earth (1795) and embellished upon by Charles Lyell in Principles of Geology (1830).

Megascopic cross-cutting relationships are features like igneous dikes, as mentioned above, which would be seen on an outcrop or in a limited geographic area.

Microscopic cross-cutting relationships are those that require study by magnification or other close scrutiny.

For example, penetration of a fossil shell by the drilling action of a boring organism is an example of such a relationship.

Cross-cutting relationships can also be used in conjunction with radiometric age dating to effect an age bracket for geological materials that cannot be directly dated by radiometric techniques.

Cross-cutting relationships can be used to determine the relative ages of rock strata and other structures. 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 dike (cutting through A, B & C); E – even younger rock strata (overlying C & D); F – normal fault (cutting through A, B, C & possibly E).