This sand on a Florida beach originated as sediment eroded from the Appalachian Mountains.
Sedimentation is the halting of movement of solid particles suspended in a liquid or gas against a barrier. The particles may originate from the erosion of a surface or chemically, by precipitation within a liquid. They move horizontally or vertically. They may be propelled by the current within the body of a gas or liquid or an external force. The most common products of this process are silts, sands and gravels in water courses, lakes and oceans and sedimentary rocks in the Earth's crust.
Sediment Motion
All natural systems tend toward a state of equilibrium that reflects an optimal use of energy. In geology, fluid and sediment gravity flows move from high to low elevations. This path is the most energy-efficient.
Settlement Sequence
Fine-grained particles such as silt and clay are transported in a suspension of air or water. They accumulate in areas where the strength of the air and water currents is low. Coarser-grained sediments are transported as a bed load in water currents or strong winds. As the energy of the air or water transport medium decreases, the coarser-grained particles settle first.
Facies
In geology, facies are the characteristics or a rock particle that demonstrate the condition of its origin or its depositional environment. Alluvial material is made from fine particles of silt and clay deposited by rivers and lakes. Rounded edges indicate water transport and sharp edges indicate wind transport. Shale, chert and chalk originated as sedimentary deposits in the deep seas.
Walther's Law
Swiss geologist Johannes Walther studied how the depositional environments of sediments change with time. He concluded in 1894 that as the depositional environment changes laterally, the sedimentation from each successive environment comes to lie on top of the previous one. A vertical sequence of facies develops that reflects the changes in the depositional environment. In this way, he recognized a landward movement of the shoreline, i.e., transgression, and a seaward movement of the shoreline, or regression. His studies led to the understanding of climate changes over geological time.
Tags: depositional environment, edges indicate, movement shoreline, silt clay, that reflects
