Hot, Cold, Wet, and Dry Hutaymah Ultramafic Inclusions: a Record of Mantle Magmatism beneath the Arabian Shield and Flanking the Red Sea Rift

Widespread Cenozoic volcanisms in the Arabian shield including &#8220;Harrats&#8221; have been referring to lithospheric thinning and/or mantle plume activity as a result of Red Sea rift-related extension.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.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.The resulting thermal and density structures show large variations, revealing strong asymmetry between the Arabian shield and Arabian platform within the Arabian Plate.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.

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Enregistrement sédimentaire des variations climatiques quaternaires sur la bordure NW du Rift de la Mer Rouge (Egypte) [ Sedimentary record of quaternary climatic changes on the NW border of the Red Sea rift (Egypt). ]

Quaternaire ◽

10.3406/quate.1994.2030 ◽

1994 ◽

Vol 5 (3) ◽

pp. 181-188

Author(s):

Odette Conchon ◽

Frédéric Baltzer ◽

Bruce Purser

Keyword(s):

Red Sea ◽

Climatic Changes ◽

Sedimentary Record ◽

Red Sea Rift

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Genesis of gabbroic intrusions in the Arabian Shield, Saudi Arabia: mineralogical, geochemical and tectonic fingerprints of the Neoproterozoic arc magmatism

Geological Magazine ◽

10.1017/s0016756821000182 ◽

2021 ◽

pp. 1-18

Author(s):

Shehata Ali ◽

Abdullah S. Alshammari

Keyword(s):

Saudi Arabia ◽

Fault System ◽

Geochemical Data ◽

Stability Field ◽

Arabian Shield ◽

Red Sea Rift ◽

Nubian Shield ◽

Najd Fault System ◽

Garnet Stability Field ◽

Arabian Nubian Shield

Abstract The Arabian Shield of Saudi Arabia represents part of the Arabian–Nubian Shield and forms an exposure of juvenile continental crust on the eastern side of the Red Sea rift. Gabbroic intrusions in Saudi Arabia constitute a significant part of the mafic magmatism in the Neoproterozoic Arabian Shield. This study records the first detailed geological, mineralogical and geochemical data for gabbroic intrusions located in the Gabal Samra and Gabal Abd areas of the Hail region in the Arabian Shield of Saudi Arabia. Geological field relations and investigations, supported by mineralogical and geochemical data, indicate that the gabbroic intrusions are generally unmetamorphosed and undeformed, and argue for their post-collisional emplacement. Their mineralogical and geochemical features reveal crystallization from hydrous, mainly tholeiitic, mafic magmas with arc-like signatures, which were probably inherited from the previous subduction event in the Arabian–Nubian Shield. The gabbroic rocks exhibit sub-chondritic Nb/U, Nb/Ta and Zr/Hf ratios, revealing depletion of their mantle source. Moreover, the high ratios of (Gd/Yb)N and (Dy/Yb)N indicate that their parental mafic melts were derived from a garnet-peridotite source with a garnet signature in the mantle residue. This implication suggests that the melting region was at a depth exceeding ∼70–80 km at the garnet stability field. They have geochemical characteristics similar to other post-collisional gabbros of the Arabian–Nubian Shield. Their origin could be explained by adiabatic decompression melting of depleted asthenosphere that interacted during ascent with metasomatized lithospheric mantle in an extensional regime, likely related to the activity of the Najd Fault System, at the end of the Pan-African Orogeny.

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Sedimentology and Evolution of the Fluvial-Deltaic System: A Modern Depositional Model Analog from the Red Sea Coastal Region, Saudi Arabia

10.2118/204558-ms ◽

2021 ◽

Author(s):

Osman Abdullatif ◽

Mutasim Osman ◽

Mazin Bashri ◽

Ammar Abdlmutalib ◽

Mohamed Yassin

Keyword(s):

Red Sea ◽

Coastal Plain ◽

Depositional Environments ◽

Hydrocarbon Reservoirs ◽

Sediment Supply ◽

Arabian Shield ◽

Space And Time ◽

Groundwater Aquifers ◽

Coastal Sabkha ◽

Lithofacies Association

Abstract Siliciclastic sediments represent important lithological unit of the Red Sea coastal plain. Their subsurface equivalents are important targets of groundwater aquifer and hydrocarbon reservoirs in the region. The lithofacies of the modern fluvial deltaic system has several distinct geomorphic units and sub-environments such as alluvial, fluvial, delta plain, aeolian, intertidal, coastal sabkha and eustuarine sediments. This study intends to characterize the lithofacies and the depositional environments and to produce an integrated facies model for this modern fluvial-deltaic system. The study might provide a valuable modern analog to several important subsurface Neogene formations that act as important hydrocarbon reservoirs and groundwater aquifers. The study integrates information and data obtained from landsats, maps and detailed field observation and measurements of facies analysis of the fluvial and deltaic along traveses from the Arabian Shield to the Red Sea coast. The lithofacies sediment analysis revealed four main lithofacies associations namely lithofacies A,B,C ad D. Lithoacies Associations A, which represents the oldest unit is dominated by coarse gravel with minor sands facies. While the lithofacies B is dominated byfine gravel and sand lithofacies, occasionally pebbly, vary from horizontal, planar to massive sands with minor laminated to massive silts and mud facies. The lithofacies in A and B show lateral proximal to distal variation as well as characteristic vertical stacking patterns. The Facies Association A and B indicates a change in fluvial depositional styles from gravelly alluvial fans to gravelly sandy fluvial systems. The lithofacies association C represents the recent fluvial system which consists of minor gravel lag deposits associated maily with various sand lithofacies of planner, horizontal and massive sand associated with massive and limainted sand and mud lithofacies. The lithofacies Association D is dominated with Barchan sand dunes local interfigger with muddy iinterdunes and sand sheets. Lithofacies D occupies rather more distal geomporphic position of the fluvial deltaic system that is adjace to coastal sabkha. The lithofacies associations described here document the evolution and development of the coastal plain sediments through space and time under various autocyclic and allocyclic controls. This included the tectonics and structural development associated with the Red Sea rifting and opening since the Oligocene – Miocene time. Others controls include the evolution of the Arabian shield (provenance) and the coastal plain through space and time as controlled by tectonics, sediment supply, climate and locally by autocyclic environmental This study might be beneficial for understanding the controls and stratigraphic evolution of the Red Sea region and will be of great value for reservoir and aquifer characterization, development and management. This modern analog model can also help in providing geological baseline information that would be beneficial for understanding similar ancient fluvial deltaic sediments. The study might provide guides and leads to understand the subsurface facies, stratigraphic architecture and heterogeneity of any potential groundwater aquifers and hydrocarbon reservoirs.

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Correlation between Structural Features during Rift Formation and Prerift Stages of the Red Sea Rift Zone

Continental Rift Formation and Its Prehistory ◽

10.1201/9781315140278-4 ◽

2021 ◽

pp. 132-141

Author(s):

A.V. Razvalyaev

Keyword(s):

Red Sea ◽

Rift Zone ◽

Structural Features ◽

Red Sea Rift

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Impact of basin architecture on diagenesis and dolomitization in a fault-bounded carbonate platform: outcrop analogue of a pre-salt carbonate reservoir, Red Sea rift, NW Saudi Arabia

Petroleum Geoscience ◽

10.1144/petgeo2018-125 ◽

2019 ◽

Vol 26 (3) ◽

pp. 448-461 ◽

Cited By ~ 6

Author(s):

Khalid Al-Ramadan ◽

Ardiansyah Koeshidayatullah ◽

Dave Cantrell ◽

Peter K. Swart

Keyword(s):

Red Sea ◽

Elevated Temperatures ◽

Carbonate Platform ◽

Isotope Analysis ◽

Carbonate Reservoir ◽

Carbonate Platforms ◽

Hydrocarbon Reservoir ◽

Red Sea Rift ◽

Platform Margin ◽

Clumped Isotope

The early Miocene Wadi Waqb carbonate in the Midyan Peninsula, NE Red Sea is of great interest not only because of its importance as an archive of one of the few pre-salt synrift carbonate platforms in the world, but also as a major hydrocarbon reservoir. Despite this importance, little is known about the diagenesis and heterogeneity of this succession. This study uses petrographical, elemental chemistry, stable isotope (δ13C and δ18O) and clumped isotope (Δ47) analyses to decipher the controlling processes behind the formation of various diagenetic products, especially dolomite, from two locations (Wadi Waqb and Ad-Dubaybah) that have experienced different diagenetic histories. Petrographically, the dolomites in both locations are similar, and characterized by euhedral to subhedral crystals (50–200 µm) and fabric-preserving dolomite textures. Clumped isotope analysis suggests that slightly elevated temperatures were recorded in the Ad-Dubaybah location (up to 49°C), whereas the Wadi Waqb location shows a sea-surface temperature of c. 30°C. These temperature differences, coupled with distinct δ18OVPDB values, can be used to infer the chemistry of the fluids involved in the dolomitization processes, with fluids at the Wadi Waqb location displaying much higher δ18OSMOW values (up to +4‰) compared to those at the Ad Dubaybah location (up to −3‰). Two different dolomitization models are proposed for the two sites: a seepage reflux, evaporative seawater mechanism at the Wadi Waqb location; and a fault-controlled, modified seawater mechanism at the Ad-Dubaybah location. At Ad-Dubaybah, seawater was modified through interaction with the immature basal sandstone aquifer, the Al-Wajh Formation. The spatial distribution of the dolostone bodies formed at these two locations also supports the models proposed here: with the Wadi Waqb location exhibiting massive dolostone bodies, while the dolostone bodies in the Ad-Dubaybah location are mostly clustered along the slope and platform margin. Porosity is highest in the slope sediments due to the interplay between higher precursor porosity, the grain size of the original limestone and dolomitization. Ultimately, this study provides insights into the prediction of carbonate diagenesis in an active tectonic basin and the resultant porosity distribution of a pre-salt carbonate reservoir system.

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