Allocthonous

Allocthonous refers to material that originates in one place and is transported to another. This term is commonly used in geology, ecology, and hydrology to describe the origin and deposition of various substances. In geology, allocthonous rocks are those that have been moved from their original location by tectonic forces, such as thrust faulting, and are now found overlying autochthonous rocks (rocks that remain in their original position). This process often results in large geological structures being displaced over considerable distances.

In ecology, allocthonous inputs are organic matter or nutrients that are transported into an ecosystem from an external source. For example, leaves falling from trees into a stream are an allocthonous input to the aquatic ecosystem. This external organic matter can be a crucial food source for the organisms living within that ecosystem, influencing its productivity and food web dynamics. Similarly, in hydrology, allocthonous sediment refers to particles that have been eroded from one area and deposited in another through the action of water. Understanding allocthonous processes is vital for comprehending the formation of geological landscapes, the functioning of ecosystems, and the movement of materials within the environment.