Facies architecture and depositional development of Middle Miocene carbonate strata at Siwa Oasis, Northwestern Egypt

Abdel‐Fattah, Zaki A.; Kora, Mahmoud; Ayyad, Salah N.

doi:10.1007/s10347-012-0332-2

Cited by 27 publications

(13 citation statements)

References 29 publications

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“…Interpretation Low-diversity miliolid-rich assemblages in Paleogene rocks indicate hypersaline or nutrient-rich shallow-water environments within the upper photic zone, where these forms might be associated with algal growth (Geel 2000;Zamagni et al 2008;Abdel-Fattah et al 2013;Sarkar 2017). The intercalation of rocks of this facies and those of FA2 would seem to support this association.…”

Section: Depositional Facies and Environmentsmentioning

confidence: 95%

The depositional history of near-surface Qatar aquifer rocks and its impact on matrix flow and storage properties

et al. 2019

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Carbonates and evaporites of Paleogene age form the shallow-aquifer rocks mantling most of Qatar, including the Paleocene and Lower Eocene Umm er Radhuma Formation and the Lower to Middle Eocene Rus and Dammam Formations. A core-based study was carried out to improve general understanding of the stratigraphic controls on aquifer matrix properties in Qatar. A cumulative total of 377 m of 10-cm-diameter core was recovered from three boreholes in central and northern Qatar, drilled to depths of greater than 120 m. Sedimentological attributes of these rocks were investigated through core and thin-section description, X-ray diffraction-based mineralogical assessment, as well as whole-rock stable isotopic analysis and integrated with interpretation of gamma-ray logs. Stratigraphic correlation of the penetrated intervals was then undertaken using sequence stratigraphic concepts and isotope stratigraphy (δ 13 C trends) in the context of recently published regional paleomaps and structural studies. In the area of Qatar, the Umm er Radhuma Formation and the overlying Traina Member of the Rus Formation were deposited in marine settings of two different basins. These basins, which extended to the south and north of Qatar, respectively, are interpreted to have been separated by a topographic high, the location of which was controlled by the presence of high-angle normal faults. The southern basin was more restricted and was the site of extensive evaporite and clay-rich siliciclastic deposition during early stages of Rus Formation. Similar evaporites and fine siliciclastic deposits are not observed in time-equivalent strata of the northern basin. During subsequent deposition of the Al Khor Member of the Rus Formation, as well as the Dammam Formation, the basins appear to have been interconnected, and fine-grained siliciclastic deposits are interbedded with, but subordinate to, carbonate strata across Qatar. Most rocks recovered for this study are dolomitic, and dolomitic rocks free of other mineral phases tend to have significant porosity (20-50%) and permeability (10-1000 mD). Decreased connectivity, flow, and storage capacity are caused by (1) the presence of gypsum beds and nodules (only southern Qatar, upper Umm er Radhuma Formation, and Rus Formation), (2) the presence of pore-occluding clays (typically palygorskite) to varying degrees in all formations, and (3) the occurrence of diagenetic calcites, most commonly in the Dammam Formation. Aquifer quality of the near-surface rocks of Qatar is in large part a function of their depositional history and is to a degree predictable using reconstruction of basin architecture, as well as sequence stratigraphic concepts.

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Section: Depositional Facies and Environmentsmentioning

confidence: 95%

The depositional history of near-surface Qatar aquifer rocks and its impact on matrix flow and storage properties

et al. 2019

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“…The eustatic rise in sea level at the Middle Miocene is probably responsible for the accumulation of these marine strata (Swezey, 2009). The major transgression during the onset of the Langhian ‘Middle Miocene’ submerged the clastic‐dominated shelf of the northern Western Desert of Egypt as well as much of the Mediterranean region (Abdel‐Fattah et al, 2013; Farouk & Khalifa, 2010). The global sea‐level rise coincided with this major transgression (Haq, Hardenbol, & Vail, 1987; Figure 13).…”

Section: Discussionmentioning

confidence: 99%

“…This matches well with the sea‐level curve of Haq et al (1987) who recorded one third‐order sequence (TB2.3) in the Langhian based on a global data set. The scattered Nile‐related river systems were locked up by the Langhian high sea‐level into a single river valley (Salem, 1976), in addition to the water turbidity and clastic influx reduced in the southwestern Mediterranean, because of the global warming event, therefore, carbonate production increased (Abdel‐Fattah et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

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Facies analysis and sequence stratigraphy of the Middle Miocene Marmarica Formation at Siwa area, north Western Desert, Egypt

et al. 2022

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The Middle Miocene rocks in the northern part of the Western Desert of Egypt are dominated by carbonate rocks that constitute the Marmarica Formation. To determine the depositional environments and sequence architecture of the Marmarica Formation, three sections were described and sampled in detail. These sections from west to east are; Girba, Naqb El‐Migahhiz, and Gabal Umm Hiyus. The Marmarica Formation in the Siwa area includes three members, from bottom to top: the Oasis, Siwa Escarpment, and El Diffa Plateau members. The microfacies of the Marmarica Formation comprise abundant mud‐supported microfacies with minor grain‐supported microfacies. Sedimentation during the Middle Miocene took place on a homoclinal ramp. Dolomitization is the most prevalent diagenetic process that affected carbonate sediments of the Marmarica Formation. The Marmarica Formation comprises two sequence boundaries. The first sequence boundary (SB1) is demarcated by the presence of Thalassinoides ichnofacies at the boundary between the Oasis and Siwa Escarpment members in all the studied sections. It is considered a type 1 sequence boundary. The second sequence boundary (SB2) is represented by an erosional surface, which is recorded only in Girba section. The SB2 was traced at both Naqb El‐Migahhiz and Umm Hiyus sections by the occurrence of burrows that relate to the Glossifungites ichnofacies. The latter boundary is considered type 2. Three third‐order depositional sequences have been recognized in the Middle Miocene Marmarica Formation. Therefore, the Marmarica Formation at Siwa Oasis exhibits relative sea‐level oscillation. During the Middle Miocene, the prevailing warm climate caused transgression and deposition of carbonates along the marine shelf surrounding western and northern Africa.

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“…In addition, the lithological similarities among these successions support uniform depositional conditions over an extensive marine platform (Gindy & El Askary 1969; Abdel‐Fattah et al . 2013).…”

Section: Location Stratigraphy and Geological Settingmentioning

confidence: 99%

Palaeoecology and taphonomy of a middle Miocene domical cheilostome bryozoan, Siwa Oasis, the northern Western Desert of Egypt

El-Hedeny

Ernest

Elsabbagh

et al. 2021

LET

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A primary study of bioerosional structures and skeletobionts associated with an almost monotypic assemblage of free‐lying bryozoan colonies of Celleporaria? sp., from the middle Miocene succession of the Siwa Oasis, Egypt, revealed four groups of encrusters (serpulids, sheet‐like cheilostome bryozoans, balanoid barnacles and oysters) and eight different ichnotaxa. Undersides of the colonies have basal exterior walls, which are relatively richer in encrusters than are the convex sides. The dominant bioerosional structures were due to the boring activities of non‐predatory organisms. The diversity of macro‐bioerosional ichnotaxa is moderate and includes Trypanites, Gastrochaenolites, Maeandropolydora, Caulostrepsis, Renichnus, Spirolites and Centrichnus. In addition, some conical borings perpendicularly penetrating the shells could belong to the predatory tracemakers of Oichnus. Despite a moderate total ichnodiversity, the observed sample diversity of ichnofossils is low (about 35% of the total specimens studied). This is explained by a relatively high sedimentation rate with only short periods of exposure on the seafloor. The dome‐shaped bryozoan occurrence is interpreted to represent a parautochthonous assemblage, which may have been influenced by shallow‐water processes in response to storm activity.

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Facies architecture and depositional development of Middle Miocene carbonate strata at Siwa Oasis, Northwestern Egypt

Cited by 27 publications

References 29 publications

The depositional history of near-surface Qatar aquifer rocks and its impact on matrix flow and storage properties

The depositional history of near-surface Qatar aquifer rocks and its impact on matrix flow and storage properties

Facies analysis and sequence stratigraphy of the Middle Miocene Marmarica Formation at Siwa area, north Western Desert, Egypt

Palaeoecology and taphonomy of a middle Miocene domical cheilostome bryozoan, Siwa Oasis, the northern Western Desert of Egypt

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