Sea waves
Explanation
Beaches are prominent coastal landforms resulting from the accumulation of loose sediments. They are classified as depositional landforms created at the interface between land and water.
Detailed Analysis:
- Sea Waves (Correct): The primary agent responsible for the formation of beaches is the action of sea waves. Waves transport sediments (sand, shingles, pebbles) towards the shore. When the energy of the waves decreases, or when the swash (water rushing up the beach) is stronger than the backwash (water receding), these sediments are deposited along the coastline, forming a beach.
- Rivers: While rivers transport sediment to the ocean, the landforms they directly create through deposition include deltas, alluvial fans, and floodplains. The redistribution of river-fed sediment to form a beach is a function of wave action.
- Wind: Wind is the primary agent for aeolian landforms, such as sand dunes and loess. While wind often shapes the dunes found immediately behind beaches, it does not form the beach itself.
- Glaciers: Glaciers are responsible for forming depositional features such as moraines, drumlins, and eskers, which are distinct from coastal beaches.
Key Takeaway:
Beaches are temporary or semi-permanent depositional landforms formed specifically by the sorting and accumulation of sediments by sea waves and coastal currents.