* Sedimentary rocks: They form in layers (strata), and the principle of superposition states that the oldest layers are at the bottom and the youngest at the top. This makes them excellent for relative age dating. They can also contain fossils, which are crucial for correlating rock layers across different locations.
* Igneous rocks: While they don't form in layers like sedimentary rocks, igneous rocks can be used for relative dating.
* Intrusive igneous rocks: These form when magma cools and solidifies within the Earth's crust. They cut through existing rocks, meaning they are younger than the rocks they intrude.
* Extrusive igneous rocks: These form from lava flows on the surface. They can be dated by comparing their composition and structure to other flows.
* Metamorphic rocks: These form when existing rocks are transformed by heat and pressure. They can be dated by examining the metamorphic minerals and structures they contain, and by relating them to the sedimentary or igneous rocks that they were derived from.
In summary: While sedimentary rocks offer the most direct evidence for relative age, all rock types can be used to determine the relative age of geological formations, by considering their relationships with other rocks and utilizing principles of superposition, cross-cutting relationships, and fossil evidence.
