What structure is defined as an up-warped, dome-shaped feature?

• A. Dome
• B. Anticline
• C. Basin
• D. Syncline

Answer: (A)

An up-warped, dome-shaped feature is a dome. It forms when rock is uplifted in a roughly circular area, so the layers bend and tilt away from the center in all directions, creating a convex, dome-like surface. The central part sits higher than the surrounding rocks, and the beds dip outward from that apex. This circular, symmetrical uplift distinguishes a dome from basins (down-warped) and from folds like anticlines and synclines (which have a hinge line and are more elongated). Domes can form from magma intrusion or broad tectonic uplift, and the outward dip pattern around the center is the key clue.