deltään

deltään is a term that refers to a geological landform. It is created by the deposition of sediment carried by a river as the flow leaves its mouth and enters slower-moving or standing water. This typically occurs where a river enters a lake, sea, or ocean. The term "delta" comes from the Greek letter delta (Δ), which resembles the triangular shape of many deltas.

The process of delta formation involves several stages. As a river flows, it carries sediment, including sand, silt, and clay, in suspension. When the river's velocity decreases upon reaching a larger body of water, it loses its capacity to carry the sediment. This causes the sediment to settle out and accumulate, gradually building up new land. Over time, these accumulated sediments form a delta.

Deltas can vary greatly in size and shape depending on factors such as the sediment load of the river, the wave and tidal energy of the receiving water body, and the geological setting. Some deltas are fan-shaped, while others may be more lobate or digitate. Notable examples include the Nile Delta in Egypt, the Mississippi River Delta in the United States, and the Ganges Delta in Bangladesh and India. These landforms are often fertile and support significant human populations and ecosystems.