Which zone is located behind dunes and comprises sand flats formed by storm-pass deposition?

• A. Dunes
• B. Barrier Flat
• C. High Salt Marsh
• D. Lagoons

Answer: (B)

In barrier island systems, the landward zone behind the dune line that is built up by storm-driven sand deposits is the barrier flat. This area is a broad, low-lying expanse of loose sand formed when waves and storm surges push sand landward and deposit it in front of and behind the dunes, creating flat, sandy plains that can host tidal channels. It differs from the dunes themselves, which are the wind-sculpted ridges that run closest to the shore. It also isn’t the high salt marsh, a vegetated wetland that usually lies just landward of the flat and is dominated by grasses rather than bare sand. Lagoons are water-filled spaces behind the barrier system, not sand flats formed by storm deposition. Thus, the barrier flat best fits the description of a zone located behind dunes comprised of sand flats formed by storm-pass deposition.