Formation of salt dome?

Salt dome = large massive body of salt, common in U.S. Gulf Coast area (onshore and offshore). Salt domes begin as horizontal layers of halite (in sedimentary rock), but due to ~low density of halite (G = 2.1) compared to overlying silicate or carbonate rock (G = 2.5 - 2.6), halite rises like flowing finger of salt. Salt punctures through overlying rock and causes upwarping of surrounding rock layers, resulting in geologic structure called dome. Some salt domes/fingers rise up to 13 km above their source. Salt domes = economic deposits of salt and possible oil traps;