Jordan Rift Valley

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A 2003 satellite image of the region showing the Jordan Rift Valley Satellite image of Israel in January 2003.jpg
A 2003 satellite image of the region showing the Jordan Rift Valley

The Jordan Rift Valley, often just Jordan Valley (Hebrew : בִּקְעָת הַיַרְדֵּןBik'at HaYarden, Arabic : الغورAl-Ghor or Al-Ghawr[ dubious ]), also called the Syro-African Depression, is an elongated depression located in modern-day Israel, Jordan, and Palestine. This geographic region includes the entire length of the Jordan River – from its sources, through the Hula Valley, the Korazim block, the Sea of Galilee, the (Lower) Jordan Valley, all the way to the Dead Sea, the lowest land elevation on Earth – and then continues through the Arabah depression, the Gulf of Aqaba whose shorelines it incorporates, until finally reaching the Red Sea proper at the Straits of Tiran.

Hebrew language Semitic language native to Israel

Hebrew is a Northwest Semitic language native to Israel, the modern version of which is spoken by over nine million people worldwide. Historically, it is regarded as the language of the Israelites and their ancestors, although the language was not referred to by the name "Hebrew" in the Tanakh itself. The earliest examples of written Paleo-Hebrew date from the 10th century BCE. Hebrew belongs to the West Semitic branch of the Afroasiatic language family. Hebrew is the only Canaanite language still spoken, and the only truly successful example of a revived dead language.

Depression (geology) Landform sunken or depressed below the surrounding area

In geology, a depression is a landform sunken or depressed below the surrounding area. Depressions form by various mechanisms.

Israel country in the Middle East

Israel, also known as the State of Israel, is a country in Western Asia, located on the southeastern shore of the Mediterranean Sea and the northern shore of the Red Sea. It has land borders with Lebanon to the north, Syria to the northeast, Jordan on the east, the Palestinian territories of the West Bank and Gaza Strip to the east and west, respectively, and Egypt to the southwest. The country contains geographically diverse features within its relatively small area. Israel's economic and technological center is Tel Aviv, while its seat of government and proclaimed capital is Jerusalem, although the state's sovereignty over Jerusalem has only partial recognition.

Contents

History and physical features

Northern section of the Great Rift Valley. The Sinai Peninsula is in center and the Dead Sea and Jordan River valley above Greatrift.jpg
Northern section of the Great Rift Valley. The Sinai Peninsula is in center and the Dead Sea and Jordan River valley above

The Jordan Rift Valley was formed many millions of years ago in the Miocene epoch (23.8 – 5.3 Myr ago) when the Arabian Plate moved northward and then eastward away from Africa. One million years later, the land between the Mediterranean and the Jordan Rift Valley rose so that the sea water stopped flooding the area.

The Miocene is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Charles Lyell; its name comes from the Greek words μείων and καινός and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene is preceded by the Oligocene and is followed by the Pliocene.

Arabian Plate A tectonic plate consisting mostly of the Arabian Peninsula, extending northward to the Levant

The Arabian Plate is a tectonic plate in the northern and eastern hemispheres.

Mediterranean Sea Sea connected to the Atlantic Ocean between Europe, Africa and Asia

The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Southern Europe and Anatolia, on the south by North Africa and on the east by the Levant. Although the sea is sometimes considered a part of the Atlantic Ocean, it is usually referred to as a separate body of water. Geological evidence indicates that around 5.9 million years ago, the Mediterranean was cut off from the Atlantic and was partly or completely desiccated over a period of some 600,000 years before being refilled by the Zanclean flood about 5.3 million years ago.

The geological and environmental evolution of the valley since its inception in the Oligocene can be seen in a variety of sedimentary and magmatic rock units, preserved as continuous sequences in the deeper basins. The outcropping formations around the basins represent alternating deposition and erosion phases. [1]

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich; the name comes from the Ancient Greek ὀλίγος and καινός, and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period.

The lowest point in the Jordan Rift Valley is in the Dead Sea, the lowest spot of which is 790 m (2,590 ft) below sea level. The shore of the Dead Sea is the lowest land on earth, at 400 m (1,300 ft) below sea level. Rising sharply to almost 1,000 m (3,300 ft) in the west, and similarly in the east, the rift is a significant topographic feature over which a few narrow paved roads and difficult mountain tracks lead. [2] The valley north of the Dead Sea has long been a site of agriculture because of water available from the Jordan River and numerous springs located on the valley's flanks.

Dead Sea Transform

The plate boundary which extends through the valley is variously called the Dead Sea Transform (DST) or Dead Sea Rift. The boundary separates the Arabian Plate from the African Plate, connecting the divergent plate boundary in the Red Sea (the Red Sea Rift) to the East Anatolian Fault in Turkey. [3]

Dead Sea Transform

The Dead Sea Transform (DST) fault system, also sometimes referred to as the Dead Sea Rift, is a series of faults that run from the Maras Triple Junction to the northern end of the Red Sea Rift. The fault system forms the transform boundary between the African Plate to the west and the Arabian Plate to the east. It is a zone of left lateral displacement, signifying the relative motions of the two plates. Both plates are moving in a general north-northeast direction, but the Arabian Plate is moving faster, resulting in the observed left lateral motions along the fault of approximately 107 km. A component of extension is also present in the southern part of the transform, which has contributed to a series of depressions, or pull-apart basins, forming the Gulf of Aqaba, Dead Sea, Sea of Galilee, and Hula basins.

African Plate Tectonic plate underlying Africa west of the East African Rift

The African Plate is a major tectonic plate straddling the equator as well as the prime meridian. It includes much of the continent of Africa, as well as oceanic crust which lies between the continent and various surrounding ocean ridges. Between 60 million years ago and 10 million years ago, the Somali Plate began rifting from the African Plate along the East African Rift. Since the continent of Africa consists of crust from both the African and the Somali plates, some literature refers to the African Plate as the Nubian Plate to distinguish it from the continent as a whole.

Red Sea Arm of the Indian Ocean between Arabia and Africa

The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. To the north lie the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez. The Red Sea is a Global 200 ecoregion. The sea is underlain by the Red Sea Rift which is part of the Great Rift Valley.

The DST fault system is generally considered to be a transform fault that has accommodated a 105-kilometre (65 mi) northwards displacement of the Arabian Plate. [4] [5] This interpretation is based on observation of offset markers, such as river terraces, gullies and archaeological features, giving horizontal slip rates of several mm per year over the last few million years. [6] GPS data give similar rates of present-day movement of the Arabian Plate relative to the Africa Plate. [7] It has also been proposed that the fault zone is a rift system that is an incipient oceanic spreading center, the northern extension of the Red Sea Rift. [8]

Global Positioning System American satellite navigation system

The Global Positioning System (GPS), originally NAVSTAR GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Air Force. It is a global navigation satellite system (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. Obstacles such as mountains and buildings block the relatively weak GPS signals.

Climate

Climate data for Dead Sea, Sedom (-390m)
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Record high °C (°F)26.4
(79.5)
30.4
(86.7)
33.8
(92.8)
42.5
(108.5)
45.0
(113.0)
46.4
(115.5)
47.0
(116.6)
44.5
(112.1)
43.6
(110.5)
40.0
(104.0)
35.0
(95.0)
28.5
(83.3)
47.0
(116.6)
Average high °C (°F)20.5
(68.9)
21.7
(71.1)
24.8
(76.6)
29.9
(85.8)
34.1
(93.4)
37.6
(99.7)
39.7
(103.5)
39.0
(102.2)
36.5
(97.7)
32.4
(90.3)
26.9
(80.4)
21.7
(71.1)
30.4
(86.7)
Daily mean °C (°F)16.6
(61.9)
17.7
(63.9)
20.8
(69.4)
25.4
(77.7)
29.4
(84.9)
32.6
(90.7)
34.7
(94.5)
34.5
(94.1)
32.4
(90.3)
28.6
(83.5)
23.1
(73.6)
17.9
(64.2)
26.1
(79.0)
Average low °C (°F)12.7
(54.9)
13.7
(56.7)
16.7
(62.1)
20.9
(69.6)
24.7
(76.5)
27.6
(81.7)
29.6
(85.3)
29.9
(85.8)
28.3
(82.9)
24.7
(76.5)
19.3
(66.7)
14.1
(57.4)
21.9
(71.4)
Record low °C (°F)5.4
(41.7)
6.0
(42.8)
8.0
(46.4)
11.5
(52.7)
19.0
(66.2)
23.0
(73.4)
26.0
(78.8)
26.8
(80.2)
24.2
(75.6)
17.0
(62.6)
9.8
(49.6)
6.0
(42.8)
5.4
(41.7)
Average precipitation mm (inches)7.8
(0.31)
9.0
(0.35)
7.6
(0.30)
4.3
(0.17)
0.2
(0.01)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
0.0
(0.0)
1.2
(0.05)
3.5
(0.14)
8.3
(0.33)
41.9
(1.65)
Average precipitation days3.33.52.51.30.20.00.00.00.00.41.62.815.6
Average relative humidity (%)41383327242324273133364132
Source: Israel Meteorological Service [9]
Climate data for Gilgal (−255m)
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Record high °C (°F)28.0
(82.4)
33.5
(92.3)
40.5
(104.9)
44.7
(112.5)
46.5
(115.7)
47.5
(117.5)
48.1
(118.6)
49.0
(120.2)
45.7
(114.3)
44.2
(111.6)
37.9
(100.2)
32.5
(90.5)
49.0
(120.2)
Average high °C (°F)20.1
(68.2)
21.6
(70.9)
25.6
(78.1)
30.3
(86.5)
35.6
(96.1)
38.7
(101.7)
40.4
(104.7)
40.0
(104.0)
37.7
(99.9)
33.8
(92.8)
27.7
(81.9)
22.1
(71.8)
31.1
(88.1)
Daily mean °C (°F)14.5
(58.1)
15.5
(59.9)
18.7
(65.7)
22.8
(73.0)
27.3
(81.1)
30.5
(86.9)
32.4
(90.3)
32.5
(90.5)
30.5
(86.9)
26.9
(80.4)
21.1
(70.0)
16.4
(61.5)
24.1
(75.4)
Average low °C (°F)8.9
(48.0)
9.4
(48.9)
11.8
(53.2)
15.3
(59.5)
19.1
(66.4)
22.3
(72.1)
24.5
(76.1)
25.0
(77.0)
23.2
(73.8)
19.9
(67.8)
14.4
(57.9)
10.6
(51.1)
17.0
(62.7)
Record low °C (°F)0.3
(32.5)
0.0
(32.0)
2.5
(36.5)
3.0
(37.4)
11.2
(52.2)
15.2
(59.4)
20.0
(68.0)
19.5
(67.1)
14.0
(57.2)
12.1
(53.8)
4.6
(40.3)
0.2
(32.4)
0.0
(32.0)
Source: Israel Meteorological Service [10]

See also

Related Research Articles

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The Great Rift Valley is a series of contiguous geographic trenches, approximately 6,000 kilometres (3,700 mi) in total length, that runs from the Beqaa Valley in Lebanon in Asia to Mozambique in southeastern Africa. While the name continues in some usages, it is rarely used in geology as it is considered an imprecise merging of separate though related rift and fault systems.

Geography of Jordan geography of the country Jordan in Southwest Asia

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Rift valley Linear lowland created by a tectonic rift or fault

A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift or fault. A rift valley is formed on a divergent plate boundary, a crustal extension or spreading apart of the surface, which is subsequently further deepened by the forces of erosion. When the tensional forces are strong enough to cause the plate to split apart, a center block drops between the two blocks at its flanks, forming a graben. The drop of the center creates the nearly parallel steeply dipping walls of a rift valley when it is new. That feature is the beginning of the rift valley, but as the process continues, the valley widens, until it becomes a large basin that fills with sediment from the rift walls and the surrounding area. One of the best known examples of this process is the East African Rift. On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust. They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically.

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Red Sea Rift

The Red Sea Rift is a spreading center between two tectonic plates, the African Plate and the Arabian Plate. It extends from the Dead Sea Transform fault system, and ends at an intersection with the Aden Ridge and the East African Rift, forming the Afar Triple Junction in the Afar Depression of the Horn of Africa.

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References

  1. The Jordan Rift Valley, Tel Aviv University
  2. David Eshel (3 May 2006). "Increasing Importance of the Jordan Rift Buffer". Defense Update.
  3. The Geophysical Institute Archived 2008-06-23 at the Wayback Machine
  4. Freund R.; Garfunkel Z.; Zak I.; Goldberg M.; Weissbrod T.; Derin B.; Bender F.; Wellings F.E.; Girdler R.W. (1970). "The Shear along the Dead Sea Rift (and Discussion)". Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences. 267 (1181): 107. Bibcode:1970RSPTA.267..107F. doi:10.1098/rsta.1970.0027.
  5. Joffe S.; Garfunkel Z. (1987). "Plate kinematics of the circum Red Sea—a re-evaluation". Tectonophysics. 141 (1–3): 5–22. Bibcode:1987Tectp.141....5J. doi:10.1016/0040-1951(87)90171-5.
  6. Begin Z.B.; Steinitz G. (2005). "Temporal and spatial variations of microearthquake activity along the Dead Sea Fault, 1984–2004". Israel Journal of Earth Sciences. 54: 1–14. doi:10.1560/QTVW-HY1E-7XNU-JCLJ.
  7. Gomez, F., Karam, G., Khawlie, M., McClusky S., Vernant P., Reilinger R., Jaafar R., Tabet C., Khair K., and Barazangi M (2007). "Global Positioning System measurements of strain accumulation and slip transfer through the restraining bend along the Dead Sea fault system in Lebanon" (PDF). Geophysical Journal International. 168 (3): 1021–1028. Bibcode:2007GeoJI.168.1021G. doi:10.1111/j.1365-246X.2006.03328.x. Archived from the original (PDF) on 2015-07-13.CS1 maint: multiple names: authors list (link)
  8. Mart Y.; Ryan W.B.F.; Lunina O.V. (2005). "Review of the tectonics of the Levant Rift system: the structural significance of oblique continental breakup". Tectonophysics. 395 (3–4): 209–232. Bibcode:2005Tectp.395..209M. doi:10.1016/j.tecto.2004.09.007.
  9. "Averages and Records for several places in Israel". Israel Meteorological Service. June 2011. Archived from the original on 2010-09-14.
  10. "Averages and Records for several places in Israel" (PDF). Israel Meteorological Service. January 2016. Archived from the original (PDF) on 2016-01-30.

Coordinates: 32°19′02″N35°34′12″E / 32.31722°N 35.57000°E / 32.31722; 35.57000