Moraine
Explanation
Geomorphic agents such as running water, wind, glaciers, and waves constantly shape the Earth's surface through erosion, transportation, and deposition. Glacial deposition occurs when a glacier melts or retreats, leaving behind the debris (rock fragments, soil, and sediment) it was carrying. These deposits are collectively known as glacial till.
Option Analysis:
- Flood plain Flood plain: This is a fluvial (river) depositional landform. It is a flat area of land next to a river, formed mainly of river sediments and subject to flooding. Therefore, this is incorrect.
- Beach: This is a coastal (marine) depositional landform formed by the action of sea waves depositing sand and pebbles along the shoreline. Therefore, this is incorrect.
- Moraine: This is a glacial depositional landform. Moraines are long ridges or mounds of deposits of glacial till. Depending on their location relative to the glacier (sides, center, or end), they are classified as lateral, medial, ground, or terminal moraines. Therefore, this is correct.
- Mushroom rock Mushroom rock: This is an aeolian (wind) erosional landform commonly found in deserts. It is formed when wind erosion wears away the softer rock at the base of a structure faster than the harder rock at the top. Therefore, this is incorrect.
Key Takeaway:
Moraines are the distinct depositional features of glaciers, consisting of unstratified and unsorted debris (till), whereas flood plains, beaches, and mushroom rocks are associated with rivers, sea waves, and wind respectively.