scholarly journals Miocene Kareem Sequence, Gulf of Suez, Egypt

GeoArabia ◽  
2010 ◽  
Vol 15 (2) ◽  
pp. 175-204 ◽  
Author(s):  
Moujahed I. Al-Husseini ◽  
M. Dia Mahmoud ◽  
Robley K. Matthews
Keyword(s):  
Sea Level ◽  
Red Sea ◽  
Arabian Plate ◽  
Gulf Of Suez ◽  
Rift Basins ◽  
Third Order ◽  
Depositional Sequence ◽  
Marine Deposits ◽  
Red Sea Rift ◽  
Global Sea Level

ABSTRACT The Miocene Kareem Formation in the Egyptian Gulf of Suez, and its equivalent formations throughout the Red Sea (250–550 m thick), contain one of the most important petroleum reservoirs in these highly faulted rift basins. They present a difficult exploration target, particularly over the shelves of the sparsely explored Red Sea for several reasons: (1) water depth exceeds one kilometer, (2) they underlie thick evaporites (including salt exceeding one kilometer in thickness), (3) they are difficult to image by conventional seismic techniques, and (4) their lithology is laterally variable and difficult to predict (anhydrite, carbonate, sandstone, shale and marl). The target Red Sea formations are best controlled by boreholes in the Gulf of Suez, where the Kareem Formation and its members are characterized by various synonymous units. A review of representative data and interpretations shows that the formation and its members are better understood when considered as a third-order, transgressive-regressive (T-R) depositional sequence, named the Kareem Sequence in the Middle East Geologic Time Scale (ME GTS). The Sequence is bounded above by the Belayim Sequence Boundary (Sub-Belayim Unconformity) and below by the Kareem Sequence Boundary (Sub-Kareem Unconformity), both corresponding to major sea-level lowstands. It contains the Arabian Plate Langhian Maximum Flooding Surface Neogene 30 (MFS Ng30) at the top of the Kareem Maximum Flooding Interval (MFI). Its lower Rahmi Member forms the majority of the transgressive systems tract (TST). The Kareem MFI and regressive systems tract (RST or HST) occur within the upper Shagar Member. The paleontology of the Formation is characterized by Planktonic Foraminiferal Zone N9 and in recent papers also N8, and Calcareous Nannofossil Biozone NN5, but the Formation’s assignment to Miocene stages (Burdigalian, Langhian and Serravallian) is unresolved in the literature. In this paper, the Kareem Sequence is interpreted in terms of Kareem subsequences 1 to 6. At semi-regional scales (10s of km), the older three are each represented by an anhydrite bed (Rahmi Anhydrite 1 to 3, each c. 10 m thick) overlain by deep-marine deposits (shale, marl and carbonate, 10s of meters thick). Subsequences 4 to 6 are represented in El Morgan field (Kareem A to C units), and in representative boreholes, by three deep-marine shale/marl units, each of which is overlain by a regressive shallow-marine sandstone unit. The Kareem Sequence is correlated to third-order orbital sequence DS3 1.1 with a depositional period of ca. 2.43 million years between ca. 16.1 and 13.7 million years before present (Ma), or numerically the latest Burdigalian, Langhian and earliest Serravallian (Langhian: 15.97–13.65 Ma in GTS 2004; 15.97–13.82 Ma in GTS 2009). The six subsequences are correlated to the orbital 405,000 year eccentricity cycle (referred to as Stratons 40–35 or DS4 1.1.1 to 1.1.6). The older three subsequences form the transgressive systems tract; the fourth contains the maximum flooding interval MFI (ca. 14.9–14.7 Ma) in its lower part. The regressive systems tract starts in the upper part of the fourth subsequence and encompasses subsequences 5 and 6. The orbital architecture of the Sequence provides a simplified framework for predicting lithology and reservoir development. The six Kareem subsequences carry the orbital-forcing glacio-eustatic signal. During low eccentricity, Antarctic ice-making and global sea-level drops, the northernmost Gulf of Suez and Bab Al Mandeb Strait restricted marine circulation in the Gulf and Red Sea rift basins. The resulting evaporitic setting was associated with the deposition of the Rahmi Anhydrite 1 to 3 beds and exposure over paleohighs. The deeper-marine deposits above the three Rahmi Anhydrite beds, and those of subsequences 4 to 6 reflect high eccentricity, Antarctic ice-melting, global sea-level rises, pluvial conditions at low latitudes (10–30oN), and open-marine circulation in the Red Sea. During pluvial periods, fluvio-deltaic systems prevailed over the mountainous rift shoulders and coastal plains and carried massive clastics into the Gulf and Red Sea Basins.

scholarly journals Late Oligocene–Early Miocene Nukhul Sequence, Gulf of Suez and Red Sea

GeoArabia ◽  
2012 ◽  
Vol 17 (1) ◽  
pp. 17-44 ◽  
Author(s):  
Moujahed I. Al-Husseini
Keyword(s):  
Red Sea ◽  
Isotope Analysis ◽  
Sedimentary Facies ◽  
Early Miocene ◽  
Rift System ◽  
Gulf Of Suez ◽  
Late Oligocene ◽  
Depositional Sequence ◽  
Red Sea Rift ◽  
Northern Red Sea

ABSTRACT Egypt’s Late Oligocene–Early Miocene Nukhul Formation was deposited during the earliest geological evolution of the Gulf of Suez and Red Sea Rift System. In this paper the formation is cast as a depositional sequence based on published sections, and correlated across the Gulf of Suez and northern Red Sea. The resulting correlations indicate that deposition was initiated in local grabens by the oldest continental clastics of the lower member of the Nukhul Formation, the Shoab Ali Member. The member overlies the Suez Rift Unconformity, a term proposed for the entire Red Sea. Although this member can attain a thickness of ca. 1,000 ft (305 m) locally in grabens, it is generally absent over horsts. Sedimentary facies of the member are interpreted as indicating an initial alluvial-fluvial setting that evolved to an estuarine and coastal setting. The upper part of the Nukhul Formation records a regional shallow-marine transgression, which can be subdivided into three correlative Upper Nukhul members. These sediments are absent over the highest paleo-horsts, but reach up to 900 ft (275 m) in thickness in grabens. In the southern Gulf of Suez the Ghara Member represents the Upper Nukhul members. In places it consists of four cycles, each of which starts with an anhydrite bed and is overlain by deposits of mixed lithology (sandstone, marl, and limestone). The four cycles are interpreted as transgressive-regressive subsequences that can be correlated across ca. 60 km in the Gulf of Suez. The Ghara Member correlates to Saudi Arabia’s Yanbu Formation, which consists of massive salt in wells drilled on the Red Sea coastal plains. The Yanbu Salt is dated by strontium-isotope analysis at ca. 23.1–21.6 Ma (earliest Aquitanian). The Nukhul Formation is capped by the Sub-Rudeis Unconformity or correlative Rudeis Sequence Boundary, and overlain by the Rudeis Formation. The Nukhul Formation is here proposed as the Nukhul Sequence and defined in the Wadi Dib-1 Well, wherein it consists of Nukhul subsequences 1 to 10 (in descending order, ranging in thickness between 33–84 m). The lower six Nukhul subsequences 10 to 5 are characterized by shale-to-sandstone cycles of the Shoab Ali Member, and the upper four are represented by the cycles of the Ghara Member. The 10 subsequences are interpreted as tracking the 405,000 year eccentricity signal of the Earth’s orbit and to span ca. 4.0 million years between ca. 25.0 and 21.0 Ma.

Biostratigraphically constrained Neogene palaeoenvironments of the Red Sea rift

2021 ◽  
Author(s):  
Geraint Hughes ◽  
Osman Varol
Keyword(s):  
Sea Level ◽  
Red Sea ◽  
Debris Flows ◽  
Middle Miocene ◽  
Depositional Environments ◽  
Early Miocene ◽  
Arabian Plate ◽  
Tectonic Activity ◽  
Gulf Of Suez ◽  
Gulf Of Aden

<p>Marine sediments deposited in response to the Neogene opening of the Red Sea during divergence of the African-Arabian plate margin provide micropalaeontological chronological evidence to calibrate synchronous palaeoenvironmental events from the Gulf of Suez to the Gulf of Aden. This facility provides insights to the timing and relative rates of tectonic subsidence associated with the rifting episodes of the region. Biostratigraphic index forms include planktonic and benthonic foraminifera and calcareous nannofossils. These, combined with various associated microfossils and macrofossil fragments, permit interpretation of a range of depositional environments that span intertidal to bathyal regimes. Onset and recovery from various hypersaline events are similarly interpreted by integrating microfossils and lithology. Following an episode of emergence and sporadic volcanicity, subsidence and the first Neogene marine transgression created brackish to shallow marine lagoons during the Early Miocene (Foraminiferal Letter Stage Upper Te). Rapid subsidence and accumulation of deep marine mudstones, of local hydrocarbon source-rock quality, with thinly interbedded siliciclastic and calciclastic debris flows commenced in the Early Miocene (Planktonic foraminiferal zones N5-N8; Nannofossil zones NN3-NN5). The debris flows increased in abundance and provide good hydrocarbon reservoirs. The Gulf of Suez and Red Sea experienced episodic isolation from the Indian Ocean during the latest Early Miocene and earliest Middle Miocene (Planktonic foraminiferal zones N8-N9; Nannofossil zone NN5 Foraminiferal Letter Stage Middle-Upper Tf1), resulting in hypersaline events with precipitation of submarine gypsum and halite. The isolation is attributed to constriction of the southern Red Sea, in the vicinity of the Bab El Mandab Straits, by eustatic sea level fall as well as probable tectonic activity; the synchronous Gulf of Aden succession does not display evidence for such hypersaline events. A prolonged hypersaline phase extended over most of the Middle Miocene, for which absence of biostratigraphic data precludes age control. During the latest Middle Miocene to Late Miocene, rejuvenation of the hinterland cause rapid deposition of terrestrial and fluviatile coarse and fine siliciclastics, with similar biostratigraphic paucity except for rare diatoms and palynomorphs. Renewed subsidence, associated with opening of the Aqaba Fault, combined with eustatic sea level rise caused marine deposition to recommence in the Pliocene.</p>

Thermal Imaging of the Lithosphere beneath Arabian Shield and Implications for "Harrats" Volcanic Field

2021 ◽  
Author(s):  
Mohamed Sobh ◽  
Khaled Zahran ◽  
Nils Holzrichter ◽  
Christian Gerhards
Keyword(s):  
Red Sea ◽  
Seismic Velocity ◽  
Volcanic Field ◽  
Arabian Plate ◽  
Thickness Variation ◽  
Arabian Shield ◽  
Lithospheric Thickness ◽  
Lithospheric Thinning ◽  
Red Sea Rift ◽  
Seismic Swarms

<p><span>Widespread Cenozoic volcanisms in the Arabian shield including “Harrats” have been referring to lithospheric thinning and/or mantle plume activity as a result of Red Sea rift-related extension.</span></p><p><span>A fundamental key in understanding the deriving mechanism of these volcanic activities and its relationship to 2007-2009 seismic swarms required a reliable model of the present-day lithospheric thermo-chemical structure.</span></p><p><span>In this work, we modeled crustal and lithospheric thickness variation as well as the variations in thermal, composition, seismic velocity, and density of the lithosphere beneath the Arabian shield within a thermodynamically self - consistent framework.</span></p><p><span>The resulting thermal and density structures show large variations, revealing strong asymmetry between the Arabian shield and Arabian platform within the Arabian Plate.</span></p><p><span>We model negative density anomalies associated with the hot mantle beneath Harrats, which coincides with the modelled lithosphere thinned (~ 65 km) as a result of the second stage of lithospheric thinning following the initial Red Sea extension.</span></p>

scholarly journals Reconstruction of the depositional sedimentary environment of Oligocene deposits (Qom Formation) in the Qom Basin (northern Tethyan seaway), Iran

Geologos ◽  
2020 ◽  
Vol 26 (2) ◽  
pp. 93-111
Author(s):  
Amrollah Safari ◽  
Hossein Ghanbarloo ◽  
Parisa Mansoury ◽  
Mehran Mohammadian Esfahani
Keyword(s):  
Sea Level ◽  
Sedimentary Environment ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Third Order ◽  
Depositional Sequences ◽  
Qom Formation ◽  
Tethyan Seaway ◽  
Qom Basin ◽  
Global Sea Level

AbstractDuring the Rupelian–Chattian, the Qom Basin (northern seaway basin) was located between the Paratethys in the north and the southern Tethyan seaway in the south. The Oligocene deposits (Qom Formation) in the Qom Basin have been interpreted for a reconstruction of environmental conditions during deposition, as well as of the influence of local fault activities and global sea level changes expressed within the basin. We have also investigated connections between the Qom Basin and adjacent basins. Seven microfacies types have been distinguished in the former. These microfacies formed within three major depositional environments, i.e., restricted lagoon, open lagoon and open marine. Strata of the Qom Formation are suggested to have been formed in an open-shelf system. In addition, the deepening and shallowing patterns noted within the microfacies suggest the presence of three third-order sequences in the Bijegan area and two third-order depositional sequences and an incomplete depositional sequence in the Naragh area. Our analysis suggests that, during the Rupelian and Chattian stages, the depositional sequences of the Qom Basin were influenced primarily by local tectonics, while global sea level changes had a greater impact on the southern Tethyan seaway and Paratethys basins. The depositional basins of the Tethyan seaway (southern Tethyan seaway, Paratethys Basin and Qom Basin) were probably related during the Burdigalian to Langhian and early Serravallian.

scholarly journals Early magmatism in the greater Red Sea rift: timing and significance

2016 ◽  
Vol 53 (11) ◽  
pp. 1158-1176 ◽  
Author(s):  
William Bosworth ◽  
Daniel F. Stockli
Keyword(s):  
Red Sea ◽  
Plate Boundary ◽  
Rift System ◽  
Northern Ethiopia ◽  
Gulf Of Suez ◽  
East African ◽  
Red Sea Rift ◽  
Lithospheric Extension ◽  
Extensional Faulting ◽  
Northern Red Sea

Throughout the greater Red Sea rift system the initial late Cenozoic syn-rift strata and extensional faulting are closely associated with alkali basaltic volcanism. Older stratigraphic units are either pre-rift or deposited during pre-rupture mechanical weakening of the lithosphere. The East African superplume appeared in northeast Africa ∼46 Ma but was not accompanied by any significant extensional faulting. Continental rifting began in the eastern and central Gulf of Aden at ∼31–30 Ma coeval with the onset of continental flood volcanism in northern Ethiopia, Eritrea, and western Yemen. Volcanism appeared soon after at Derudeb in southern Sudan and at Harrats Hadan and As Sirat in Saudi Arabia. From ∼26.5 to 25 Ma a new phase of volcanism began with the intrusion of a dike field reaching southeast of Afar into the Ogaden. At 24–23 Ma dikes were emplaced nearly simultaneously north of Afar and reached over 2000 km into northern Egypt. The dike event linked Afar to the smaller Cairo mini-plume and corresponds to initiation of lithospheric extension and rupture in the central and northern Red Sea and Gulf of Suez. By ∼21 Ma the dike intrusions along the entire length of the Red Sea were completed. Each episodic enlargement of the greater Red Sea rift system was triggered and facilitated by breakthrough of mantle-derived plumes. However, the absence of any volumetrically significant rift-related volcanism during the main phase of Miocene central and northern Red Sea – Gulf of Suez rifting supports the interpretation that plate–boundary forces likely drove overall separation of Arabia from Africa.

Depositional Cycles in a Lower Cretaceous Limestone Reservoir, Onshore Abu Dhabi, U.A.E.

2018 ◽  
Vol 88 (7) ◽  
pp. 753-776 ◽  
Author(s):  
Stephen N. Ehrenberg ◽  
Stephen W. Lokier ◽  
Liu Yaxin ◽  
Rulin Chen
Keyword(s):  
Sea Level ◽  
Lower Cretaceous ◽  
Clay Content ◽  
Storm Events ◽  
Humid Climate ◽  
Third Order ◽  
Depositional Sequence ◽  
The Third ◽  
Depositional Cycles ◽  
Order Sequence

AbstractThe upper reservoir zone of the Lower Cretaceous Kharaib Formation (46–54 m thick in the studied wells) is regarded as the upper portion of a third-order depositional sequence comprising higher-order cycles. Whereas the third-order sequence interpretation is clearly supported by the upward-shoaling trend of the reservoir zone, relationships defining the component cycles have not previously been documented and are the focus of the present study. Core descriptions from four wells in a single oilfield reveal little evidence of facies changes or trends of facies patterns indicative of high-frequency depositional cycles. Cycle boundaries could possibly be represented by the repetitive pattern of coarse beds (rudstone and floatstone) 0.1–2 m thick, commonly having sharp basal contacts and gradational upper contacts with enclosing packstone to wackestone. Because the coarse beds do not appear correlative between wells, however, we prefer the alternative interpretation that they reflect episodic storm events which locally redistributed detritus, sourced from a patchwork of low-relief lithosomes, across the flat surface of the epeiric Kharaib platform–lagoon. Although the existence of high-order eustatic fluctuations during upper Kharaib deposition is well established, low-amplitude variations in water depth may not have touched down on the sea floor to significantly affect sediment textures in contrast with the dominant storm signal.Reservoir sub-zones used for production operations, but previously suggested to be fourth-order parasequence sets, are defined by dips in porosity-log profiles, reflecting thin (approximately 1 m) intervals of increased stylolite frequency. These boundaries are thus diagenetic in character, but their correlation over tens to hundreds of kilometers indicates an underlying depositional control. We suggest that the link between sea level and diagenesis is depositional-clay content, which facilitates stylolitic dissolution. Profiles of bulk-rock alumina analyses in the studied cores show subtle indications of higher clay content at the sub-zone tops. Much greater clay peaks mark the third-order sequence boundaries, resulting in the “dense” (very low porosity) zones above and below the studied reservoir zone and the increased stylolite frequency in the upper and lower several meters of the zone. Possible factors promoting clay influx across a carbonate shelf during falls in sea level include increased stream gradients and more humid climate.

Crustal evaluation of the northern Red Sea rift and Gulf of Suez, Egypt from geophysical data: 3-dimensional modeling

2006 ◽  
Vol 45 (3) ◽  
pp. 257-278 ◽  
Author(s):  
Salah Saleh ◽  
Thomas Jahr ◽  
Gerhard Jentzsch ◽  
Ahmed Saleh ◽  
N.M. Abou Ashour
Keyword(s):  
Red Sea ◽  
Geophysical Data ◽  
Gulf Of Suez ◽  
3 Dimensional ◽  
Dimensional Modeling ◽  
Red Sea Rift ◽  
Northern Red Sea

scholarly journals Seismic Stratigraphic Analysis and Hydrocarbon Potential of Miocene-Quaternary Deposits in the Western Nile Delta Basin

2021 ◽  
Vol 54 (2C) ◽  
pp. 1-12
Author(s):  
Mahmoud Elsheikh
Keyword(s):  
Sea Level ◽  
Deep Sea ◽  
Nile Delta ◽  
Field Analysis ◽  
Sedimentary Sequence ◽  
Third Order ◽  
Relative Level ◽  
Depositional Sequence ◽  
Well Data ◽  
Middle Pliocene

This study focuses on the subsurface Miocene-Pleistocene sedimentary sequence of the Western Delta of Deep-Sea field. Analysis of seismic, based on obtainable well data, and seismic data, allows us to divide the studied successions into two mega sequences: Pre and Post Messinian complexes resulting in transgressive-regressive sedimentation cycles of sea level during the evolution of the Miocene-Pleistocene subsurface sedimentary sequence. The Relative level of the sea was extremely falling in the time of the Messinian period, although it was largely rising at the time of the lower to Middle Pliocene. Pre-Messinian complex encompasses the Miocene strata, while the Post-Messinian complex consists of a thickness pattern of deposits in the time of Pliocene to Pleistocene and ended up with Holocene. The comprehensive study presented here divides these complexes into several orders of sea-level cycles. Pre and Post-Messinian complexes are consisting of several third-order cycles, which is called a depositional sequence, hence the thickness pattern starts from Sidi Salem Formation and ends up with Mit Ghamr Formation (Pleistocene). The interpreted anticline represents a characteristic overlap that can create an appropriate structural trap for hydrocarbons in the sandy intermission of the formations of the Western Deep-Sea Delta field such as Kafr El Sheik siliceous clastic. Besides, the recognized individual and various hidden routes, such as channel and sub-channel in the Pre-Messinian complex are approved for additional inspection to discover hydrocarbons.

scholarly journals Significant new biostratigraphic horizons in the Qusaiba Member of the Silurian Qalibah Formation of central Saudi Arabia, and their sedimentologic expression in a sequence stratigraphic context

GeoArabia ◽  
2005 ◽  
Vol 10 (1) ◽  
pp. 49-92 ◽  
Author(s):  
A. Miller Merrell ◽  
Melvin John
Keyword(s):  
Saudi Arabia ◽  
Sea Level ◽  
Arabian Plate ◽  
Important Species ◽  
Sequence Stratigraphic ◽  
Facies Associations ◽  
Global Sea Level ◽  
High Level ◽  
A Minor ◽  
Stratigraphic Evolution

ABSTRACT Detailed analysis of over 1,000 subsurface Silurian palynology samples from 34 wells has allowed the development of a robust biostratigraphy based on acritarchs, chitinozoans and cryptospores for the Qusaiba Member of the Qalibah Formation, central Saudi Arabia. The new index fossils described herein augment the Arabian Plate Silurian chitinozoan zonation. The high-resolution biostratigraphic zonation consists of nine First Downhole Occurrences (FDOs) from the lower Telychian through Aeronian. In particular, three regionally recognizable palynologic horizons were identified within the lower part of the informally designated Mid-Qusaiba Sandstone (Angochitina hemeri Interval Zone), and above the FDO of Sphaerochitina solutidina. This high level of biostratigraphic resolution provides a framework for the integration of the sedimentology and calibration with global sea level curves, leading to a detailed understanding of the sequence stratigraphic evolution of this part of the Silurian in Saudi Arabia. Sedimentological core studies identify three Depositional Facies Associations (DFAs) within the Mid-Qusaiba Sandstone interval, including: (1) shelfal deposits (DFA-I) characterized by interbedded hummocky cross-stratified sandstones, graded siltstones and bioturbated mudstones; (2) turbiditic deposits (DFA-II); and (3) an association of heavily contorted and re-sedimented sandstones, siltstones and mudstones (DFA-III) that is considered representative of oversteepened slopes upon the Qusaiba shelf. Integration of the newly recognized palynostratigraphic horizons and the sedimentological data facilitates an understanding of the sequence stratigraphic evolution of the Mid-Qusaiba Sandstone interval and its immediate precursors. Thus a Maximum Flooding Surface (MFS) is identified from significant palynostratigraphic, as well as sedimentological evidence, and concurs with the MFS identified regionally with the Monograptus convolutus Graptolite Zone. Several mud-prone cyclothems downlap onto the MFS. Each of these is identified by its own palynostratigraphic marker: these mud-prone cyclothems represent the distal parts of a Highstand Systems Tract (HST). The end of the HST is marked by evidence of a major, episodic drop in relative sea level. Thus, a relationship is identified wherein successive palynostratigraphic marker horizons, newly identified in this study, are partially eroded by the introduction of sandy turbidites (DFA-II). These turbidites arise from storm-induced erosion of gully complexes in the upper submarine slopes that are present as topography upon the Qusaiba shelf. Each of the successive drops in sea level is separated from the next by a minor, subsequent sea level rise, which precludes further submarine erosion and turbidite deposition, and is instead evident in the widespread occurrence of shallow marine (shelfal) muds and sandy tempestites (DFA-I). The lowstand per se is considered to be represented by the most widespread distribution of the DFA-II turbidite deposits, and is associated with the youngest Mid-Qusaiba Sandstone marker horizon identified in this study, namely Rugosphaera agglomerata n.sp. The youngest unit of DFA-II lowstand turbidites is limited in its occurrence to the more proximal parts of the study area, and thus is considered to represent the onset of the succeeding Transgressive Systems Tract (TST). Of the biostratigraphic indices used for correlation within the Qusaiba Member, Rugosphaera agglomerata and Eupoikilofusa curvata are formally described and two additional important species, Fractoricoronula n.sp. and ?Oppilatala n.sp., are retained in open nomenclature.

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