GENERAL GEOLOGY

Detailed explanation-1: -An intrusion is always younger than the rock layers around and beneath it. More clues come from the study of faults. A fault is a break in Earth’s crust.

Detailed explanation-2: -Rock layers get disturbed by faults or intrusions and then have weak spots and break shifting the layers of rock. If a fault or intrusion cuts through an unconformity, the fault or intrusion is younger than all the rocks it cuts through above and below it.

Detailed explanation-3: -An intrusion is a body of igneous (created under intense heat) rock that has crystallized from molten magma. Gravity influences the placement of igneous rocks because it acts on the density differences between the magma and the surrounding wall rocks (country or local rocks).

Detailed explanation-4: -The bottom layer of rock forms first, which means it is oldest. Each layer above that is younger, and the top layer is youngest of all. This ordering is relative because you cannot be sure exactly when each layer formed, only that each layer is younger then the one below it.