The Syrian Arc is a series of
fold structures that extend from Syria, through
Lebanon
Lebanon ( , ar, لُبْنَان, translit=lubnān, ), officially the Republic of Lebanon () or the Lebanese Republic, is a country in Western Asia. It is located between Syria to the north and east and Israel to the south, while Cyprus li ...
and
Palestine
__NOTOC__
Palestine may refer to:
* State of Palestine, a state in Western Asia
* Palestine (region), a geographic region in Western Asia
* Palestinian territories, territories occupied by Israel since 1967, namely the West Bank (including East ...
into northern
Sinai
Sinai commonly refers to:
* Sinai Peninsula, Egypt
* Mount Sinai, a mountain in the Sinai Peninsula, Egypt
* Biblical Mount Sinai, the site in the Bible where Moses received the Law of God
Sinai may also refer to:
* Sinai, South Dakota, a place ...
and on into
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
's
Eastern
Eastern may refer to:
Transportation
*China Eastern Airlines, a current Chinese airline based in Shanghai
*Eastern Air, former name of Zambia Skyways
*Eastern Air Lines, a defunct American airline that operated from 1926 to 1991
*Eastern Air Li ...
and
Western deserts. The folds started forming during the
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
epoch as a result of the closure of the
Neotethys Ocean that caused shortening of the
continental margin
A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin ...
with reactivation of the extensional
faults formed during the
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
period.
Extent
The furthest west that folds have been attributed to the Syrian Arc deformation phase is in the northern Western Desert near
Matruh. The area of folding continues to the east forming a broad zone about 200 km wide passing into the Eastern Desert, including major structures such as
Kattaniya and the
breached anticline at
Wadi Araba
The Arabah, Araba or Aravah ( he, הָעֲרָבָה, ''hāʿĂrāḇā''; ar, وادي عربة, ''Wādī ʿAraba''; lit. "desolate and dry area") is a loosely defined geographic area south of the Dead Sea basin, which forms part of the borde ...
on the western side of the
Gulf of Suez
The Gulf of Suez ( ar, خليج السويس, khalīǧ as-suwais; formerly , ', "Sea of Calm") is a gulf at the northern end of the Red Sea, to the west of the Sinai Peninsula. Situated to the east of the Sinai Peninsula is the smaller Gulf of ...
. In Sinai, a series of other breached anticlinal structures are developed, such as those at
Halal
''Halal'' (; ar, حلال, ) is an Arabic word that translates to "permissible" in English. In the Quran, the word ''halal'' is contrasted with ''haram'' (forbidden). This binary opposition was elaborated into a more complex classification kno ...
,
Maghara
Maghara ( ar, المغارة) is a Syrian village located in Ihsim Nahiyah in Ariha District, Idlib
ar, إدلبي, Idlibi
, coordinates =
, elevation_m = 500
, area_code = 23
, ...
and
Yelleg.
Geometry
The Syrian Arc has an overall S-shape, with structures trending WSW–ENE in Egypt and Syria and SSW–NNE trending in the intervening section.
The Palmyra fold belt
In Syria the main Syrian Arc structure is the WSW–ENE trending
Palmyra fold belt. It extends eastward from the
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 (a junction with the East Anatolian Fault in southeastern Turkey) to the northern end of the ...
, dying out near the
Euphrates Graben. The left lateral offset of the Palmyrides against the other part of the Syrian Arc across the Dead Sea Transform has been estimated as a maximum of about 107 km.
Origin
Two main phases of tectonics were responsible for the formation of the Syrian Arc structures. The first, dominated by
extensional tectonics
Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary body's crust or lithosphere.
Deformation styles
The types of structure and the geometries formed depend on ...
, was associated with the development of a
passive margin
A passive margin is the transition between oceanic and continental lithosphere that is not an active plate margin. A passive margin forms by sedimentation above an ancient rift, now marked by transitional lithosphere. Continental rifting creat ...
in northern Africa as the Neotethys Ocean was formed. The second, dominated by
contractional tectonics,
was associated with the closure of that ocean. Some of the structures were further modified in the
Cenozoic
The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
during the formation of the Dead Sea Transform and the continued northward movement of the
Arabian Plate
The Arabian Plate is a minor tectonic plate in the Northern and Eastern Hemispheres.
It is one of the three continental plates (along with the African and the Indian Plates) that have been moving northward in geological history and collidin ...
.
Passive margin formation
During the
Permian
The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...
, a period of
rift
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics.
Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-grabe ...
ing affected northern Africa associated with the development of the Neotethys Ocean and the breaking away of the
Cimmerian continent. This rifting continued intermittently during the
Triassic
The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...
,
Jurassic
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
and early
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
periods. This prolonged extensional episode formed a large number of sedimentary basins within the passive margin, with a mainly Jurassic to
Lower Cretaceous
Lower may refer to:
*Lower (surname)
*Lower Township, New Jersey
*Lower Receiver (firearms)
*Lower Wick
Lower Wick is a small hamlet located in the county of Gloucestershire, England. It is situated about five miles south west of Dursley, eight ...
fill.
Neotethys closure
![Bosworth & Tari 2021 Fig7](https://upload.wikimedia.org/wikipedia/commons/f/f5/Bosworth_%26_Tari_2021_Fig7.png)
As part of the overall convergence between the African and Eurasian plates, the Neotethys ocean began to close. This led to a change in the prevailing stress field in the passive margin to one of regional compression, NNW–SSE orientated.
This caused reactivation of many of the extensional faults bounding the
half-graben
A half-graben is a geological structure bounded by a fault along one side of its boundaries, unlike a full graben where a depressed block of land is bordered by parallel faults.
Rift and fault structure
A rift is a region where the lithosphere ...
basins,
inverting them. The first phase of inversion folding appears to have started in the
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. The ...
age.
Several further pulses of folding occurred during the
Paleogene
The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
in the Western Desert.
References
{{Reflist
Geology of Egypt
Geology of Israel
Geology of Lebanon
Geology of Syria
Western Desert (Egypt)