Cross-cutting relationships

What principle of relative dating is illustrated by the dikes and faults

Megascopic crosscutting relationships are features likeIn a similar example

Within a sequence of rock layers formed at Earth's surface, rock layers higher in the sequence are older. Metamorphic rocks are close to horizontal when eroded. For example, if a fault were truncated by an unconformity, and that unconformity cut by a dike. Within a sequence of rock layers formed at Earth's surface, rock layers in the middle of a sequence are older.

Microscopic cross-cutting relationships are those that require study by magnification or other close scrutiny. Sedimentary rocks are close to horizontal when eroded. In other words, these relationships have various scales.

Cross-cutting relationships may be compound in nature. This provides an age bracket, or range of possible ages, for the layer in question. This process lead to a system of time containing eons, eras, periods, and epochs all determined by their position in the rock record.

We know this

Part E Five layers of rock are cut by two faults. Relative time places events or formations in order based on their position within the rock record relative to one another using six principles of relative dating. Faults A and B are about the same age, and both are older than the five layers of rock.

Part E Five layers of rock

With out individual time stamps the process of dating these structures could become extremely difficult. Within a sequence of rock layers formed at Earth's surface, rock layers lower in the sequence are older.

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. In a similar example, an impact crater excavates into a subsurface layer of rock. We know this because the fault underlies the igneous rocks.

Structural relationships may be faults or fractures cutting through an older rock. Fault A breaks through to the surface, while Fault B does not.