F | GeologyRocks

F

Frequency-dependent selection

Selection of a genotype depending on its frequency in the population, e.g. scale eating fish. See resource polymorphism.

Frost Wedging

Also known as congelifraction, frost weathering or frost shattering. When a rock is exposed such that water is liquid during the day, but freezes at night, the expansion of the freezing water can cause stress in the rock such that it can shatter. This is most common in deserts where water in the rock will freeze rapidly during the night.

Fulgurite

A hollow tube of glass (predominantly lechatelierite, which is naturally fused silica dioxide or Quartz) formed when lightning strikes quartz-rich sand. Often referred to as "petrified lighting".