Question

The principle of ____________________ tells us that a fault must be older than the rocks that it cuts.

Answer 1

The Principle of Cross-Cutting tells us that a fault must be older than the rock it cuts. Cross-cutting in geology was formulated by Nicolas Steno, a Danish geologist in the mid-1600's. It is usually used in combination with radiometric age dating, which can tell the geologist how old the rock is.