Lake Lisan
Encyclopedia
Lake Lisan was a prehistoric lake that existed between 70,000 to 12,000 BC in the Great Rift Valley
in the Near East
. It is sometimes referred to as a Pleistocene
lake.
Lisan means tongue in Arabic relating to the shape of the Lisan Peninsula where studies of the sediment
formations were taken. The sediment formations left by the lake extend from Lake Tiberias (the Sea of Galilee) in the north to a boundary ridge ca. 35 km south of the Dead Sea
. The lake left behind a layer of lacustrine
sediment that blankets the Jordan Valley with terraces of sediment up to 40 m thick. These sediments are commonly called Marls and are composed of layers beds of true loams and calcareous
silt
loams mixed with other chemicals and salts. At its height, the lake covered several other basins in the area with a maximum area of ca. 2000 km2, a length of 200 km and a width of no more than 17 km.
The formations were named the Lisan deposits and first described by Lartet in 1869 after visiting the Dead Sea in the Spring of 1864. He noted a correlation of a wet period in the Levant
with a glacial period in Europe
. It was not until Geographer E. Huntindon visited in 1909 that it was realized it was measure of historical precipitation
for the area. The first stratigraphic study of the sediments was carried out by Picard in 1943 who developed a chronology he called the Lisan series. It was not until later studies were carried out at lake level that a more detailed chronology of the lacustrine
record was developed.
These studies determined the highest stand of the lake to be around 180 metres below sea level at around 24,000 to 26,000 ca. BC. when it formed a complete lake all the way along the Jordan Valley, approximately 200 metres higher than the current level of the Dead Sea
. This started to decline around 17,000 ca. BC with the sharpest drop in level occurring through 14,000 to 13,000 BC to around 500 metres below sea level, representing possibly the largest lake level drop in the last 70,000 years, occurring over a period of only around 1000 years. This rapid lowering created a flattened valley floor, known in modern times as the Ghor. Tectonic factors have been suggested as a possible cause for these events and it has been argued that the level receded as far as 700 metres below sea level, then gradually refilled.
Climatic and tectonic changes caused the level in the Jordan Valley to fluctuate into the holocene
, leaving Lake Beisan
in the basin around Beit She'an still extant into the Bronze Age
. Archaeological evidence also supports these levels with no Kebaran
sites located between 17,000 BC and 13,500 BC below a level of 203 metres below sea level. Early Natufian sites are also located between 215 and 230 metres below sea level, indicating a high level and receding shoreline after this date.
Great Rift Valley
The Great Rift Valley is a name given in the late 19th century by British explorer John Walter Gregory to the continuous geographic trench, approximately in length, that runs from northern Syria in Southwest Asia to central Mozambique in South East Africa...
in the Near East
Near East
The Near East is a geographical term that covers different countries for geographers, archeologists, and historians, on the one hand, and for political scientists, economists, and journalists, on the other...
. It is sometimes referred to as a Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
lake.
Lisan means tongue in Arabic relating to the shape of the Lisan Peninsula where studies of the sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
formations were taken. The sediment formations left by the lake extend from Lake Tiberias (the Sea of Galilee) in the north to a boundary ridge ca. 35 km south of the Dead Sea
Dead Sea
The Dead Sea , also called the Salt Sea, is a salt lake bordering Jordan to the east and Israel and the West Bank to the west. Its surface and shores are below sea level, the lowest elevation on the Earth's surface. The Dead Sea is deep, the deepest hypersaline lake in the world...
. The lake left behind a layer of lacustrine
Lacustrine
Lacustrine means "of a lake" or "relating to a lake".Specifically, it may refer to:*Lacustrine plain*Lacustrine delta-Fish:*Lacustrine goby , a type of small fish found in Philippine waters belonging to the Gobiidae family, known in Tagalog as dulong-See also:*Fluvial - of or relating a...
sediment that blankets the Jordan Valley with terraces of sediment up to 40 m thick. These sediments are commonly called Marls and are composed of layers beds of true loams and calcareous
Calcareous
Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...
silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
loams mixed with other chemicals and salts. At its height, the lake covered several other basins in the area with a maximum area of ca. 2000 km2, a length of 200 km and a width of no more than 17 km.
The formations were named the Lisan deposits and first described by Lartet in 1869 after visiting the Dead Sea in the Spring of 1864. He noted a correlation of a wet period in the Levant
Levant
The Levant or ) is the geographic region and culture zone of the "eastern Mediterranean littoral between Anatolia and Egypt" . The Levant includes most of modern Lebanon, Syria, Jordan, Israel, the Palestinian territories, and sometimes parts of Turkey and Iraq, and corresponds roughly to the...
with a glacial period in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. It was not until Geographer E. Huntindon visited in 1909 that it was realized it was measure of historical precipitation
Precipitation
Precipitation may refer to:* Precipitation , rain, sleet, hail, snow and other forms of water falling from the sky* Precipitation , the condensation of a solid from a solution during a chemical reaction...
for the area. The first stratigraphic study of the sediments was carried out by Picard in 1943 who developed a chronology he called the Lisan series. It was not until later studies were carried out at lake level that a more detailed chronology of the lacustrine
Lacustrine
Lacustrine means "of a lake" or "relating to a lake".Specifically, it may refer to:*Lacustrine plain*Lacustrine delta-Fish:*Lacustrine goby , a type of small fish found in Philippine waters belonging to the Gobiidae family, known in Tagalog as dulong-See also:*Fluvial - of or relating a...
record was developed.
These studies determined the highest stand of the lake to be around 180 metres below sea level at around 24,000 to 26,000 ca. BC. when it formed a complete lake all the way along the Jordan Valley, approximately 200 metres higher than the current level of the Dead Sea
Dead Sea
The Dead Sea , also called the Salt Sea, is a salt lake bordering Jordan to the east and Israel and the West Bank to the west. Its surface and shores are below sea level, the lowest elevation on the Earth's surface. The Dead Sea is deep, the deepest hypersaline lake in the world...
. This started to decline around 17,000 ca. BC with the sharpest drop in level occurring through 14,000 to 13,000 BC to around 500 metres below sea level, representing possibly the largest lake level drop in the last 70,000 years, occurring over a period of only around 1000 years. This rapid lowering created a flattened valley floor, known in modern times as the Ghor. Tectonic factors have been suggested as a possible cause for these events and it has been argued that the level receded as far as 700 metres below sea level, then gradually refilled.
Climatic and tectonic changes caused the level in the Jordan Valley to fluctuate into the holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
, leaving Lake Beisan
Lake Beisan
Lake Beisan was a prehistoric lake that existed from ca. 12,000 to 5,000 BC in the north of the Jordan Valley in the Near East near modern day Beit She'an....
in the basin around Beit She'an still extant into the Bronze Age
Bronze Age
The Bronze Age is a period characterized by the use of copper and its alloy bronze as the chief hard materials in the manufacture of some implements and weapons. Chronologically, it stands between the Stone Age and Iron Age...
. Archaeological evidence also supports these levels with no Kebaran
Kebaran
The Kebaran or Kebarian culture was an archaeological culture in the eastern Mediterranean area , named after its type site, Kebara Cave south of Haifa...
sites located between 17,000 BC and 13,500 BC below a level of 203 metres below sea level. Early Natufian sites are also located between 215 and 230 metres below sea level, indicating a high level and receding shoreline after this date.