Nice small map titled Mer Morte, from wood engraving  with fine detail and clear impression, nice hand coloring. Overall size approx.  20 x 11.5 cm, image size approx. 12 x 5 cm. From La Nouvelle Géographie universelle, la terre et les hommes, 19 vol. (1875-94), great work of Elisee Reclus. Cartographer is Charles Perron.

Dead Sea

Arabic Al-Baḥr al-Mayyit , Hebrew Yam HaMelaẖ , also known as  Salt Sea

landlocked salt lake between Israel and Jordan, which lies some 1,300 feet (400  metres) below sea level—the lowest elevation and the lowest body of water on the  surface of the Earth. Its eastern shore belongs to Jordan, and the southern half  of its western shore belongs to Israel. The northern half of the western shore  lies within the Palestinian West Bank and has been under Israeli occupation  since the 1967 Arab-Israeli war.

The Dead Sea lies between the hills of Judaea to the west and the Transjordanian  plateaus to the east. The Jordan River flows from the north into the Dead Sea,  which is 50 miles (80 km) long and attains a width of 11 miles (18 km). Its  surface area is about 394 square miles (1,020 square km). The peninsula of  Al-Lisān (Arabic: “The Tongue”) divides the lake on its eastern side into two  unequal basins: the northern basin encompasses about three-fourths of the lake's  total surface area and reaches a depth of 1,300 feet (400 metres); the southern  basin is smaller and shallower (less than 10 feet [3 metres] on average). During  biblical times and up to the 8th century CE, only the area around the northern  basin was inhabited, and the lake was about 115 feet (35 metres) below its level  of the late 20th century. It rose to its highest level (1,275 feet [389 metres]  below sea level) in 1896 but receded again after 1935.

The name Dead Sea can be traced back at least to the Hellenistic epoch (323 to  30 BCE). The Dead Sea figures in biblical accounts dating to the time of Abraham  (progenitor of the Hebrews) and the destruction of Sodom and Gomorrah (the two  cities along the lake, according to the Hebrew bible, that were destroyed by  fire from heaven because of their wickedness). The desolate wilderness beside  the lake offered refuge to David (king of Israel) and later to Herod I (the  Great; king of Judaea), who at the time of the siege of Jerusalem by the  Parthians in 40 BCE barricaded himself in a fortress at Masada. Masada was the  scene of a two-year siege that culminated in the mass suicide of its Jewish  Zealot defenders and the occupation of the fortress by the Romans in 73 CE. The  Jewish sect that left the biblical manuscripts known as the Dead Sea Scrolls  took shelter in caves northwest of the lake.

The Dead Sea occupies part of a graben (a downfaulted block of the Earth's  crust) between transform faults along a tectonic plate boundary that runs from  the Red Sea–Gulf of Suez spreading centre to a convergent plate boundary in the  Taurus Mountains. The eastern fault, along the edge of the Moab Plateau, is more  readily visible from the lake than is the western fault, which marks the gentler  Judaean upfold.

In the Jurassic and Cretaceous periods (about 200 to 65 million years ago),  before the creation of the graben, an extended Mediterranean Sea covered Syria  and Palestine. During the Miocene Epoch (23 to 5.3 million years ago), as the  Arabian tectonic plate collided with the Eurasian plate to the north, upheaval  of the seabed produced the upfolded structures of the Transjordanian highlands  and the central range of Palestine, causing the fractures that allowed the Dead  Sea graben to drop. At that time, the Dead Sea was probably about the size that  it is today. During the Pleistocene Epoch (2,600,000 to 11,700 years ago), it  rose to an elevation of about 700 feet (200 metres) above its modern level,  forming a vast inland sea that stretched some 200 miles (320 km) from the Ḥula  Valley area in the north to 40 miles (64 km) beyond its present southern limits.  The Dead Sea did not spill over into the Gulf of Aqaba because it was blocked by  a 100-foot (30-metre) rise in the highest part of Wadi Al-ʿArabah, a seasonal  watercourse that flows in a valley to the east of the central Negev highlands.

Beginning about 2.5 million years ago, heavy streamflow into the lake deposited  thick sediments of shale, clay, sandstone, rock salt, and gypsum. Later, strata  of clay, marl, soft chalk, and gypsum were dropped upon layers of sand and  gravel. With the water evaporating faster than it was replenished by  precipitation over the last 10,000 years, the lake gradually shrank to its  present form. In so doing, it bared deposits that cover the Dead Sea valley to a  thickness of about 1 to 4 miles (2 to 6 km).

The peninsula of Al-Lisān and Mount Sedom (historically Mount Sodom) resulted  from movements of the Earth's crust. Mount Sedom's steep cliffs rise up from the  southwestern shore. Al-Lisān is formed of strata of clay, marl, soft chalk, and  gypsum interbedded with sand and gravel. Both Al-Lisān and beds made of similar  material on the western side of the Dead Sea valley dip to the east. It is  assumed that the uplifting of Mount Sedom and Al-Lisān formed a southern  escarpment for the Dead Sea. Later the sea broke through the western half of  this escarpment to flood what is now the shallow southern end of the Dead Sea.

The Dead Sea lies in a desert. Rainfall is scanty and irregular. Al-Lisān  averages about 2.5 inches (65 mm) of rain a year, the industrial site of Sedom  (near historical Sodom) only about 2 inches (50 mm). Owing to the lake's low  elevation and sheltered location, winter temperatures are mild, averaging 63 °F  (17 °C) in January at the southern end at Sedom and 58 °F (14 °C) at the  northern end; freezing temperatures are unheard of. Summer is very hot,  averaging 93 °F (34 °C) in August at Sedom, with a recorded maximum of 124 °F  (51 °C). Evaporation of the lake's waters—estimated at about 55 inches (1,400  mm) a year—often creates a thick mist above the lake. On the rivers the  atmospheric humidity varies from 45 percent in May to 62 percent in October.  Lake and land breezes, which are relatively common, blow off the lake in all  directions in the daytime and then reverse direction to blow toward the centre  of the lake at night.

The inflow from the Jordan River, whose high waters occur in winter and spring,  averages 19 billion cubic feet (540 million cubic metres) per year. Four modest  but perennial streams descend from Jordan on the east through deep gorges: the  wadis Al-ʿUẓaymī, Zarqāʾ Māʿīn, Al-Mawjib, and Al-Ḥasā. Down numerous other  wadis, streams flow spasmodically and briefly from the neighbouring heights as  well as from the depression of Wadi Al-ʿArabah. Thermal sulfur springs also feed  the rivers. Evaporation in summer and the intake of water, especially in winter  and spring, cause seasonal variations in the level of the lake of from 12 to 24  inches (30 to 60 cm).

The waters of the Dead Sea are extremely saline, and the concentration of salt  increases toward the bottom. In effect, two different masses of water exist in  the lake. Down to a depth of 130 feet (40 metres), the temperature varies from  66 to 98 °F (19 to 37 °C), the salinity is slightly less than 300 parts per  thousand, and the water is especially rich in sulfates and in bicarbonates.  Beneath a zone of transition located between 130 and 330 feet (40 and 100  metres), the water has a uniform temperature of about 72 °F (22 °C) and a higher  degree of salinity (approximately 332 parts per thousand); it contains hydrogen  sulfide and strong concentrations of magnesium, potassium, chlorine, and  bromine. The deep water is saturated with sodium chloride, which precipitates to  the bottom. The deep water is fossilized (i.e., being very salty and dense, it  remains permanently on the bottom); the near-surface water dates from a few  centuries after biblical times.

The saline water has a high density that keeps bathers buoyant. The fresh water  of the Jordan stays on the surface; in the spring its muddy colour can be traced  across the lake as far as 30 miles (50 km) south of the point where the river  empties into the Dead Sea.

The lake's extreme salinity excludes all forms of life except bacteria. Fish  carried in by the Jordan or by smaller streams when in flood die quickly. Apart  from the vegetation along the rivers, plant life along the shores is  discontinuous and consists mainly of halophytes (plants that grow in salty or  alkaline soil).

The Dead Sea constitutes an enormous salt reserve. Rock salt deposits also occur  in Mount Sedom along the southwestern shore. The salt has been exploited on a  small scale since antiquity. In 1929 a potash factory was opened near the mouth  of the Jordan. Subsidiary installations were later built in the south at Sedom,  but the original factory was destroyed during the 1948–49 Arab-Israeli war. A  factory producing potash, magnesium, and calcium chloride was opened in Sedom in  1955. Another plant produces bromine and other chemical products.

Because of its location on the contested Jordanian-Israeli frontier, navigation  on the Dead Sea is negligible. Its shores are nearly deserted, and permanent  establishments are rare. Exceptions are the factory at Sedom, a few hotels and  spas in the north, and, in the west, a kibbutz (an Israeli agricultural  community) in the region of the ʿEn Gedi oasis. Small cultivated plots are also  occasionally found on the lakeshore.