Glossary
| Term | Definition |
|---|---|
| Facies | An association of rock types which share a common trait. In the case of sedimentary rocks, usually used with reference to the environment in which the sediments were deposited (for example, deltaic). |
| Fault | Any brittle failure of rock layers along which rocks are displaced on one side relative to the other. |
| Fault trap | A structural trap where at least one of the components of closure is formed by offset of rock layers across a fault. |
| Fold | Deformation of a rock surface. |
| Formation | A formal term used to reference a genetically related rock unit (e.g. the Monterey Formation). |
| Four way dip | A simple structure in which rock surfaces dip in all four directions, thus creating structural closure. Often forms a hydrocarbon trap. |