New
7 Natural Wonders of the World
New Seven Wonders of Nature-One
of 28 nominees. Winners will be announced in 2011.
The Dead Sea ("Sea
of Salt") is a salt lake in Jordan
to the east and in the West Bank and
Israel to the west. Its surface and
shores are 422 metres (1,385 ft) below
sea level,[3] the lowest elevation
on the Earth's surface on dry land.
The Dead Sea is 378 m (1,240 ft) deep,
the deepest hypersaline lake in the
world. It is also one of the world's
saltiest bodies of water, with 33.7%
salinity. Only Lake Assal (Djibouti),
Garabogazköl and some hypersaline
lakes of the McMurdo Dry Valleys in
Antarctica (such as Don Juan Pond
and perhaps Lake Vanda) have a higher
salinity. It is 8.6 times as salty
as the ocean.[4] This salinity makes
for a harsh environment where animals
cannot flourish, hence its name. The
Dead Sea is 67 kilometres (42 mi)
long and 18 kilometres (11 mi) wide
at its widest point. It lies in the
Jordan Rift Valley, and its main tributary
is the Jordan River.
The Dead Sea has attracted
visitors from around the Mediterranean
basin for thousands of years. Biblically,
it was a place of refuge for King
David. It was one of the world's first
health resorts (for Herod the Great),
and it has been the supplier of a
wide variety of products, from balms
for Egyptian mummification to potash
for fertilizers. People also use the
salt and the minerals from the Dead
Sea to create cosmetics and herbal
sachets.
Natural
history
There are two contending hypotheses
about the origin of the low elevation
of the Dead Sea. The older hypothesis
is that it 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
extension of the crust with consequent
subsidence.
Around three million
years ago what is now the valley of
the Jordan River, Dead Sea, and Wadi
Arabah was repeatedly inundated by
waters from the Mediterranean Sea.
The waters formed in a narrow, crooked
bay which was connected to the sea
through what is now the Jezreel Valley.
The floods of the valley came and
went depending on long scale climate
change. The lake that occupied the
Dead Sea Rift, named "Lake Sodom",
deposited beds of salt, eventually
coming to be 3 km (2 miles) thick.
According to geological
theory, approximately two million
years ago the land between the Rift
Valley and the Mediterranean Sea rose
to such an extent that the ocean could
no longer flood the area. Thus, the
long bay became a lake.
The first such prehistoric
lake is named "Lake Gomorrah."
Lake Gomorrah was a freshwater or
brackish lake that extended at least
80 km (50 mi) south of the current
southern end of the Dead Sea and 100
km (60 mi) north, well above the present
Hula Depression. As the climate became
more arid, Lake Gomorrah shrank and
became saltier. The large, saltwater
predecessor of the Dead Sea is called
"Lake Lisan."
.
Pebbles cemented with halite on the
western shore of the Dead Sea near
Ein Gedi.In prehistoric times great
amounts of sediment collected on the
floor of Lake Gomorrah. The sediment
was heavier than the salt deposits
and squeezed the salt deposits upwards
into what are now the Lisan Peninsula
and Mount Sodom (on the southwest
side of the lake). Geologists explain
the effect in terms of a bucket of
mud into which a large flat stone
is placed, forcing the mud to creep
up the sides of the pail. When the
floor of the Dead Sea dropped further
due to tectonic forces, the salt mounts
of Lisan and Mount Sodom stayed in
place as high cliffs. (see salt domes)
From 70 000 to 12 000
years ago the lake level was 100 m
(328 ft) to 250 m (820 ft) higher
than its current level. This lake,
called "Lake Lisan", fluctuated
dramatically, rising to its highest
level around 26,000 years ago, indicating
very wet climate in the Near East.
Sometime around 10 000 years ago the
lake level dropped dramatically, probably
to levels even lower than today. During
the last several thousand years the
lake has fluctuated approximately
400 m (1,310 ft) with some significant
drops and rises. Current theories
as to the cause of this dramatic drop
in levels rule out volcanic activity,
therefore it may have been a seismic
event.[2]
In between Israel and
Jordan lies the lowest place on earth,
otherwise known as the Dead Sea. This
body of water has its own unique and
spectacular atmosphere. Although its
extremely salty waters do not allow
for aquatic life to survive, the Dead
Sea has been a natural health mecca
for thousands of years.
