Dead Sea hypothesis is that the Dead Sea lies in a true rift zone, an extension of the Red Sea Rift, or even of the Great Rift Valley of eastern Africa. A more recent hypothesis is that the Dead Sea basin is a consequence of a "step-over" discontinuity along the Dead Sea Transform, creating an extension of the crust with consequent subsidence. Around 3.7 million years ago, what is now the valley of the Jordan River, Dead Sea, and the northern Wadi Arabah was repeatedly inundated by waters from the Mediterranean Sea. The waters formed in a narrow, crooked bay that is
Dead Sea in the northern part of the Dead Sea and barely in the southern part. The Dead Sea zone's aridity is due to the rainshadow effect of the Judaean Mountains. The highlands east of the Dead Sea receive more rainfall than the Dead Sea itself. To the west of the Dead Sea, the Judaean mountains rise less steeply and are much lower than the mountains to the east. Along the southwestern side of the lake is a tall halite formation called "Mount Sodom". There are two contending hypotheses about the origin of the low elevation of the Dead Sea. The older