Question

a geologist is studying a sand dune. the sand dune was formed as wind deposited sand against an obstruction. what process created the sand dune?
abrasion
deflation
weathering
compaction

Explanation:

To determine the process creating the sand dune, we analyze each option:

• Abrasion: Wind - driven sediment scraping surfaces (erosion, not deposition).
• Deflation: Wind removing loose sediment (erosion, but leftover sediment can deposit into dunes as wind slows at obstructions).
• Weathering: Breaking down rocks (not direct dune formation).
• Compaction: Sediment pressing together (post - deposition, not formation).

Sand dunes form from wind - deposited sand (sediment deposition) after deflation removes finer particles, leaving sand to accumulate at obstructions. So deflation is linked to the sediment source for dune formation.

Answer:

B. deflation