In terrestrial environments, sediment transport is driven by which processes?

• A. Wind and gravity, with deposition occurring after movement.
• B. Ocean currents move sediment on land.
• C. Tectonic uplift lifts sediment upward.
• D. Rain dissolves sediment.

Answer: (A)

In terrestrial settings, sediment moves mainly because of wind and gravity, and it settles once its motion loses energy. Wind can pick up and transport loose particles, especially fine sand and dust, and then deposit them when winds drop or obstacles appear, creating features like dunes and layered loess. Gravity drives downslope movement through mass wasting—rockfalls, landslides, and slower creep—carrying sediment downhill until it settles when the slope flattens or the material is interrupted. Rainfall can contribute to erosion via surface runoff, but dissolving sediment is not how solid material is moved; dissolution is a chemical process, not a primary transport mechanism. Ocean currents act in the marine environment, not on land, and tectonic uplift moves land upward rather than continuously transporting surface sediment downslope.