Gulf of Suez Rift
Encyclopedia
The Gulf of Suez Rift is a continental rift
zone that was active between the Late Oligocene
(ca. 28 Ma) and the end of the Miocene
(ca. 5 Ma). It represented a continuation of the Red Sea Rift
until break-up occurred in the middle Miocene, with most of the displacement on the newly developed Red Sea spreading centre being accommodated by the Dead Sea Transform
. During its brief post-rift history, the deepest part of the remnant rift topography has been filled by the sea, creating the Gulf of Suez
.
North of the Gulf of Suez the rift becomes indistinct and its exact geometry uncertain, linking eventually to the Manzala rift beneath the Nile delta
.
with respect to the African Plate
. This model is consistent with near orthogonal rifting along the entire length of the rift system. Alternative models that suggest initiation by strike-slip faulting and pull-apart basin development along the axis of the rift have not been supported by detailed studies of the rift geometry.
Towards the end of the Miocene, the Arabian Plate began to collide with the Eurasian Plate leading to changes in the plate configuration, the development of the Dead Sea Transform and cessation in rifting in the Gulf of Suez.
. Gneiss
es, volcanics and metasediment
s are intruded by granite
s, granodiorite
s and a suite of dolerite dykes
. These rocks contain shear zones, such as the Rehba Shear Zone of western Sinai, that are interpreted to have partly controlled the orientation and location of rift structures.
, a result of peneplain
ation. These red and white sandstone
units have a combined thickness of about 500 m. They were deposited in a continental environment except in the northeastern part of the gulf where they become marine. The next preserved sequence is the Umm Bogma or Abu Durba Formations of lower Carboniferous
age, which sit apparently conformably on the Cambrian, although the base represents a hiatus of about 150 Ma. The Umm Bogma Formation is dolomitic
, while the stratigraphically equivalent Abur Durba Formation consists of black shale
s and mudstone
s. These sequences then pass up into the sandstones of the Abu Thora Formation. In the northern Gulf, at Wadi Araba, the early Carboniferous is overlain by upper Carboniferous of the Rod e Hamal, Abu Darag and Ahmeir Formations. In the southern Gulf the Carboniferous strata are capped by Permian
volcanics
.
in age, although it is considered to include Permian strata near its base near Wadi Araba. The Qiseib Formation consists of sandstones, conglomeratic
at the base with an overall fining upward trend.
The Qiseib Formation is overlain by the sandstones of the Malha Formation of upper Jurassic
to lower Cretaceous
age. These sandstones are up to 400 m in thickness, form an important reservoir in the Gulf of Suez and are known informally as the 'Nubian' sandstone.
The upper Cretaceous sequence consists of shallow marine deposits that generally thicken northwards. The Cenomanian
Raha Formation, a sequence of interbedded shales limestones and sandstone, is succeeded by limestones of the Turonian
Wata Formation. This is overlain by sandstones and shales of the Coniacian
-Santonian
age Matullah Formation. The central and northern parts of the gulf were locally affected by a phase of inversion
at the end of the Santonian. Structures such as Wadi Araba became uplifted at this time giving rise to folding and local erosion of pre-Campanian
strata. The Campanian Duwi Formation, known as the Brown Limestone, was deposited throughout the gulf apart from the uplifted area of the North Galala plateau and Wadi Araba where it is replaced by chalk of the Thelmet Formation. These pass up into Sudr Formation chalks of Maastrichtian
age. On the southern margin of the uplifted Wadi Araba, a carbonate ramp sequence was formed during the Campanian/Maastrichtian, continuing into the Paleogene
.
age are represented by the Esna Shale Formation which overlies the Sudr Formation. This is succeeded by Eocene
age limestones of either the Thebes or Waseiyit Formations. Together with the middle to late Eocene Mokattam Formation this sequence reaches a combined maxiumum thickness of 500 m. These limestones are followed by continental to locally shallow marine red sandstones of the Tayiba Formation, which represent the last of the pre-rift deposits.
The continental sandstones and siltstones of the Abu Zenima Formation represent the earliest syn-rift deposits of late Oligocene (Chattian
) to early Miocene (Aquitanian
) age. Locally the Abu Zenima Formation is capped by basalt
s. The lower Miocene age conglomerates, sandstones and marl
s of the Nukhul Formation were deposited in shallow marine conditions as the sea began to flood the developing rift. The Nukhul Formation overlies the Abu Zenima Formation in some place but elsewhere is probably age equivalent, reflecting a diachronous
change to marine conditions within the rift.
The deepening of the rift is recorded by the lower Miocene Rudeis Formation. The lower part, consisting of marls and sandstones, is overlain by coarse sandstones and conglomerates reflecting a rapid increase in rift topography at that time. The Kareem Formation saw the first development of evaporite
s, indicating basin restriction, followed by open marine shales, as coarse clastic deposition began to reduce in the middle Miocene. Shales, anhydrite
, halite
and reef
al limestones of the uppermost middle Miocene Belayim lie unconformably on the Kareem. More restricted basin conditions continued with the upper Miocene South Gharib and Zeit Formations with deposition of halite with some anhydrite and mudstone, representing the last syn-rift deposits.
The Pliocene–Recent postrift sequence reaches up to 2000 m in thickness in the southern part of the rift and is formed of interbedded sandstones, limestones and evaporites.
. A series of WSW-ENE trending extensional basins were inverted, creating isolated uplifted and folded areas known as 'Syrian arc' structures. These structures were mainly active during the Late Santonian but there is evidence of further movements on the same structures at the end of the Cretaceous and during the Paleogene.
stage (late Early Miocene) (ca. 18 Ma). In the Middle Miocene break-up occurred along the whole length of the Red Sea rift with seafloor spreading beginning in the Late Miocene. This break-up was associated with a gradual reduction in the rate of rifting along the Gulf of Suez with most activity stopping by the beginning of the Pliocene.
accompanied by flooding of the topographically lowest parts of the rift.
fields and discoveries have been reported from the Gulf of Suez rift with a variety of petroleum play
s.
in the Gulf of Suez is the Campanian age Brown Limestone or Duwi Member of the Sudr Formation. This unit is typically 25–70 m thick and is distributed from the southern end of the gulf as far north as Wadi Araba. It contains mainly type II kerogen
and has an average Total organic carbon
content (TOC) of 2.6 wt% with some samples measuring up to 21 wt%. In the southern part of the gulf, the Miocene source intervals become important as higher geothermal gradients cause parts of the syn-rift sequence to reach maturity. Marine shale
of the middle Miocene
Magna Formation is the most important of these younger source rocks with a TOC ranging from 1–2 wt %.
Rift
In geology, a rift or chasm is a place where the Earth's crust and lithosphere are being pulled apart and is an example of extensional tectonics....
zone that was active between the Late Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
(ca. 28 Ma) and the end of the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
(ca. 5 Ma). It represented a continuation of the Red Sea Rift
Red Sea Rift
The Red Sea Rift is a spreading center between two tectonic plates, the African Plate and the Arabian Plate. It extends down the length of the Red Sea, stretching from the southern end of the Dead Sea Transform to a triple junction with the Aden Ridge and the East African Rift in the Afar...
until break-up occurred in the middle Miocene, with most of the displacement on the newly developed Red Sea spreading centre being accommodated by the Dead Sea Transform
Dead Sea Transform
The Dead Sea Transform fault system, also sometimes referred to as the Dead Sea Rift, is a geologic fault which runs from the Maras Triple Junction to the northern end of the Red Sea Rift...
. During its brief post-rift history, the deepest part of the remnant rift topography has been filled by the sea, creating the Gulf of Suez
Gulf of Suez
The northern end of the Red Sea is bifurcated by the Sinai Peninsula, creating the Gulf of Suez in the west and the Gulf of Aqaba to the east. The Gulf of Suez is formed within a relatively young, but now inactive rift basin, the Gulf of Suez Rift, dating back about 28 million years...
.
North of the Gulf of Suez the rift becomes indistinct and its exact geometry uncertain, linking eventually to the Manzala rift beneath the Nile delta
Nile Delta
The Nile Delta is the delta formed in Northern Egypt where the Nile River spreads out and drains into the Mediterranean Sea. It is one of the world's largest river deltas—from Alexandria in the west to Port Said in the east, it covers some 240 km of Mediterranean coastline—and is a rich...
.
Plate tectonic setting
The formation of the Red Sea – Gulf of Suez rift system was caused by the anticlockwise rotation of the Arabian PlateArabian Plate
The Arabian Plate is one of three tectonic plates which have been moving northward over millions of years and colliding with the Eurasian Plate...
with respect to the African Plate
African Plate
The African Plate is a tectonic plate which includes the continent of Africa, as well as oceanic crust which lies between the continent and various surrounding ocean ridges.-Boundaries:...
. This model is consistent with near orthogonal rifting along the entire length of the rift system. Alternative models that suggest initiation by strike-slip faulting and pull-apart basin development along the axis of the rift have not been supported by detailed studies of the rift geometry.
Towards the end of the Miocene, the Arabian Plate began to collide with the Eurasian Plate leading to changes in the plate configuration, the development of the Dead Sea Transform and cessation in rifting in the Gulf of Suez.
Basement
The basement consists of Precambrian rocks of the Arabian-Nubian ShieldArabian-Nubian Shield
The Arabian-Nubian Shield is an exposure of Precambrian crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. Geographically - and from north to south - the ANS includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea,...
. Gneiss
Gneiss
Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks.-Etymology:...
es, volcanics and metasediment
Metasediment
In geology, metasediment is sediment or sedimentary rock that shows evidence of having been subjected to metamorphism. The overall composition of a metasediment can be used to identify the original sedimentary rock, even where they have been subject to high-grade metamorphism and intense...
s are intruded by granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
s, granodiorite
Granodiorite
Granodiorite is an intrusive igneous rock similar to granite, but containing more plagioclase than orthoclase-type feldspar. Officially, it is defined as a phaneritic igneous rock with greater than 20% quartz by volume where at least 65% of the feldspar is plagioclase. It usually contains abundant...
s and a suite of dolerite dykes
Dike (geology)
A dike or dyke in geology is a type of sheet intrusion referring to any geologic body that cuts discordantly across* planar wall rock structures, such as bedding or foliation...
. These rocks contain shear zones, such as the Rehba Shear Zone of western Sinai, that are interpreted to have partly controlled the orientation and location of rift structures.
Palaeozoic
Cambrian rocks of Araba and Naqus Formations occur throughout the region above a planar unconformityUnconformity
An unconformity is a buried erosion surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval of time before deposition of the younger, but the term is used to describe...
, a result of peneplain
Peneplain
A peneplain is a low-relief plain representing the final stage of fluvial erosion during times of extended tectonic stability. The existence of peneplains, and peneplanation as a geomorphological process, is not without controversy, due to a lack of contemporary examples and uncertainty in...
ation. These red and white sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
units have a combined thickness of about 500 m. They were deposited in a continental environment except in the northeastern part of the gulf where they become marine. The next preserved sequence is the Umm Bogma or Abu Durba Formations of lower Carboniferous
Carboniferous
The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...
age, which sit apparently conformably on the Cambrian, although the base represents a hiatus of about 150 Ma. The Umm Bogma Formation is dolomitic
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
, while the stratigraphically equivalent Abur Durba Formation consists of black shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
s and mudstone
Mudstone
Mudstone is a fine grained sedimentary rock whose original constituents were clays or muds. Grain size is up to 0.0625 mm with individual grains too small to be distinguished without a microscope. With increased pressure over time the platey clay minerals may become aligned, with the...
s. These sequences then pass up into the sandstones of the Abu Thora Formation. In the northern Gulf, at Wadi Araba, the early Carboniferous is overlain by upper Carboniferous of the Rod e Hamal, Abu Darag and Ahmeir Formations. In the southern Gulf the Carboniferous strata are capped by Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
volcanics
Volcanic rock
Volcanic rock is a rock formed from magma erupted from a volcano. In other words, it is an igneous rock of volcanic origin...
.
Mesozoic
The Qiseib Formation is found throughout the Gulf varying in thickness between 8 m and 300 m. It is thought to be mainly TriassicTriassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
in age, although it is considered to include Permian strata near its base near Wadi Araba. The Qiseib Formation consists of sandstones, conglomeratic
Conglomerate (geology)
A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
at the base with an overall fining upward trend.
The Qiseib Formation is overlain by the sandstones of the Malha Formation of upper Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
to lower Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
age. These sandstones are up to 400 m in thickness, form an important reservoir in the Gulf of Suez and are known informally as the 'Nubian' sandstone.
The upper Cretaceous sequence consists of shallow marine deposits that generally thicken northwards. The Cenomanian
Cenomanian
The Cenomanian is, in the ICS' geological timescale the oldest or earliest age of the Late Cretaceous epoch or the lowest stage of the Upper Cretaceous series. An age is a unit of geochronology: it is a unit of time; the stage is a unit in the stratigraphic column deposited during the corresponding...
Raha Formation, a sequence of interbedded shales limestones and sandstone, is succeeded by limestones of the Turonian
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...
Wata Formation. This is overlain by sandstones and shales of the Coniacian
Coniacian
The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...
-Santonian
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 85.8 ± 0.7 mya and 83.5 ± 0.7 mya...
age Matullah Formation. The central and northern parts of the gulf were locally affected by a phase of inversion
Inversion (geology)
In structural geology inversion or basin inversion relates to the relative uplift of a sedimentary basin or similar structure as a result of crustal shortening. This normally excludes uplift developed in the footwalls of later extensional faults, or uplift caused by mantle plumes...
at the end of the Santonian. Structures such as Wadi Araba became uplifted at this time giving rise to folding and local erosion of pre-Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...
strata. The Campanian Duwi Formation, known as the Brown Limestone, was deposited throughout the gulf apart from the uplifted area of the North Galala plateau and Wadi Araba where it is replaced by chalk of the Thelmet Formation. These pass up into Sudr Formation chalks of Maastrichtian
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
age. On the southern margin of the uplifted Wadi Araba, a carbonate ramp sequence was formed during the Campanian/Maastrichtian, continuing into the Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...
.
Cenozoic
Rocks of PaleocenePaleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
age are represented by the Esna Shale Formation which overlies the Sudr Formation. This is succeeded by Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
age limestones of either the Thebes or Waseiyit Formations. Together with the middle to late Eocene Mokattam Formation this sequence reaches a combined maxiumum thickness of 500 m. These limestones are followed by continental to locally shallow marine red sandstones of the Tayiba Formation, which represent the last of the pre-rift deposits.
The continental sandstones and siltstones of the Abu Zenima Formation represent the earliest syn-rift deposits of late Oligocene (Chattian
Chattian
The Chattian is, in the geologic timescale, the youngest of two ages or upper of two stages of the Oligocene epoch/series. It spans the time between and . The Chattian is preceded by the Rupelian and is followed by the Aquitanian .-Stratigraphic definition:The Chattian was introduced by Austrian...
) to early Miocene (Aquitanian
Aquitanian
Aquitanian could refer to:*Aquitanian age, a geological age, the first stage of the Miocene Epoch*Aquitanian language, an ancient language spoken in the region later known as Gascony* Anything originating from Aquitaine, a region of France....
) age. Locally the Abu Zenima Formation is capped by basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
s. The lower Miocene age conglomerates, sandstones and marl
Marl
Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite. Marl was originally an old term loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay...
s of the Nukhul Formation were deposited in shallow marine conditions as the sea began to flood the developing rift. The Nukhul Formation overlies the Abu Zenima Formation in some place but elsewhere is probably age equivalent, reflecting a diachronous
Diachronous
A diachronous deposit in Geology is a sedimentary rock formation in which apparently similar material varies in age from place to place....
change to marine conditions within the rift.
The deepening of the rift is recorded by the lower Miocene Rudeis Formation. The lower part, consisting of marls and sandstones, is overlain by coarse sandstones and conglomerates reflecting a rapid increase in rift topography at that time. The Kareem Formation saw the first development of evaporite
Evaporite
Evaporite is a name for a water-soluble mineral sediment that result from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporate deposits, marine which can also be described as ocean deposits, and non-marine which are found in standing bodies of...
s, indicating basin restriction, followed by open marine shales, as coarse clastic deposition began to reduce in the middle Miocene. Shales, anhydrite
Anhydrite
Anhydrite is a mineral – anhydrous calcium sulfate, CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium and strontium sulfates, as might be expected from the...
, halite
Halite
Halite , commonly known as rock salt, is the mineral form of sodium chloride . Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities...
and reef
Reef
In nautical terminology, a reef is a rock, sandbar, or other feature lying beneath the surface of the water ....
al limestones of the uppermost middle Miocene Belayim lie unconformably on the Kareem. More restricted basin conditions continued with the upper Miocene South Gharib and Zeit Formations with deposition of halite with some anhydrite and mudstone, representing the last syn-rift deposits.
The Pliocene–Recent postrift sequence reaches up to 2000 m in thickness in the southern part of the rift and is formed of interbedded sandstones, limestones and evaporites.
History
Pre-rift
During the Late Cretaceous to Eocene, the area now occupied by the rift was a shallow sea depositing carbonates. This period was mainly quiet tectonically but the northern part of the gulf region was affected by periodic far-field effects of the Alpine orogenyAlpine orogeny
The Alpine orogeny is an orogenic phase in the Late Mesozoic and Tertiary that formed the mountain ranges of the Alpide belt...
. A series of WSW-ENE trending extensional basins were inverted, creating isolated uplifted and folded areas known as 'Syrian arc' structures. These structures were mainly active during the Late Santonian but there is evidence of further movements on the same structures at the end of the Cretaceous and during the Paleogene.
Rifting
Rifting began along the whole of the Red Sea -Gulf of Suez rift system during the Late Oligocene. In the Gulf of Suez rift, the rifting culminated during the BurdigalianBurdigalian
The Burdigalian is, in the geologic timescale, an age or stage in the early Miocene. It spans the time between 20.43 ± 0.05 Ma and 15.97 ± 0.05 Ma...
stage (late Early Miocene) (ca. 18 Ma). In the Middle Miocene break-up occurred along the whole length of the Red Sea rift with seafloor spreading beginning in the Late Miocene. This break-up was associated with a gradual reduction in the rate of rifting along the Gulf of Suez with most activity stopping by the beginning of the Pliocene.
Post-rift
Since the end of the Miocene the area of the Gulf of Suez rift has begun to experience post-rift thermal subsidenceThermal subsidence
In geology and geophysics, thermal subsidence is a mechanism of subsidence in which conductive cooling of the mantle thickens the lithosphere and causes it to decrease in elevation. This is because of thermal contraction: as mantle material cools and becomes part of the mechanically-rigid...
accompanied by flooding of the topographically lowest parts of the rift.
Geometry
The Gulf of Suez rift is strongly segmented along its length with half-grabens of alternating polarity. The changes in fault polarity and position from segment to segment are taken up by broad accommodation zones.Zaafarana accommodation zone
This zone, also known as the Galala-Abu Zenima Accommodation Zone, marks a change in fault polarity from NE-dipping in the Darag Basin to the north to SE-dipping to the south in the Belayim province. It coincides with the location of the Cretaceous inversion structure, the Wadi Araba anticline. It has been suggested that the presence of this structure acted as a barrier to northward propagation of the rift. Its location may also be partly controlled by the Rehba Shear Zone in the underlying basement.Morgan accommodation zone
The Morgan accommodation zone marks a switch in fault polarity from NE-dipping to the north to SW-dipping to the south in the Amal-Zeit province. It also coincides with a marked southward widening of the rift zone. There is no earlier structure known that influenced the location of this accommodation zone.Economic importance
More than 120 hydrocarbonHydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
fields and discoveries have been reported from the Gulf of Suez rift with a variety of petroleum play
Petroleum play
In geology, a petroleum play, or simply a play, is a group of petroleum fields or prospects in the same region that are controlled by the same set of geological circumstances.The normal steps in the play cycle are:...
s.
Source rocks
The main source rockSource rock
In petroleum geology, source rock refers to rocks from which hydrocarbons have been generated or are capable of being generated. They form one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposited in a variety of environments including...
in the Gulf of Suez is the Campanian age Brown Limestone or Duwi Member of the Sudr Formation. This unit is typically 25–70 m thick and is distributed from the southern end of the gulf as far north as Wadi Araba. It contains mainly type II kerogen
Kerogen
Kerogen is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic solvents because of the huge molecular weight of its component compounds. The soluble portion is known as bitumen. When heated to the right...
and has an average Total organic carbon
Total organic carbon
Total organic carbon is the amount of carbon bound in an organic compound and is often used as a non-specific indicator of water quality or cleanliness of pharmaceutical manufacturing equipment....
content (TOC) of 2.6 wt% with some samples measuring up to 21 wt%. In the southern part of the gulf, the Miocene source intervals become important as higher geothermal gradients cause parts of the syn-rift sequence to reach maturity. Marine shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
of the middle Miocene
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene....
Magna Formation is the most important of these younger source rocks with a TOC ranging from 1–2 wt %.