Describe how the following landforms are created. Identify the depositional agent responsible for the formation of the given landforms. a. Delta b. Alluvinal till c. Glacial d. Loess e. Sand dunes
Answer:
a. Delta: Deltas are landforms formed at the mouth of a river where it meets a body of water, such as an ocean or a lake. Deltas are created by the deposition of sediment carried by the river as it slows down upon entering the stiller water. As the river loses its velocity, it drops the sediment it has been carrying, resulting in the formation of a delta. The depositional agent responsible for the formation of a delta is water.
b. Alluvial fan: Alluvial fans are fan-shaped landforms that are created when a fast-flowing river or stream abruptly slows down and spreads out onto a flat or gently sloping plain. The sudden decrease in velocity causes the river to deposit the sediment it has been carrying, resulting in the formation of an alluvial fan. The depositional agent responsible for the formation of alluvial fans is water.
c. Glacial: Glacial landforms are created by the movement and erosion of glaciers. Glaciers are large bodies of ice that slowly flow over the land, picking up rocks, sediment, and debris along the way. As glaciers move, they erode the landscape, creating features such as U-shaped valleys, cirques, and moraines. The depositional agent responsible for the formation of glacial landforms is ice.
d. Loess: Loess is a type of fine-grained, wind-blown sediment that is deposited over large areas. It is formed from the accumulation of silt-sized particles that have been carried by the wind over long distances. Loess deposits are typically found in regions with a dry climate and a lack of vegetation to anchor the soil. The depositional agent responsible for the formation of loess is wind.
e. Sand dunes: Sand dunes are formed by the wind's action on loose sand. When wind encounters an obstacle, such as vegetation or a change in topography, it slows down and drops the sand it has been carrying. Over time, this accumulation of sand forms dunes. The depositional agent responsible for the formation of sand dunes is wind.