Papers by Emad S . Sallam
Carbonates and Evaporites, Jun 21, 2022
The Quaternary calcareous tufas precipitated in the Kurkur Oasis area in the southern Western Des... more The Quaternary calcareous tufas precipitated in the Kurkur Oasis area in the southern Western Desert of Egypt were analyzed to determine their implications for the construction of environmental conditions during their formation. X-ray diffraction analysis showed that the tufas consist of low-Mg calcite, whereas macroscopic and microscopic analyses showed the presence of both allochthonous (clastic) and autochthonous components consisting predominantly of pisoliths, oncoids, intraclasts, lithoclasts, stromatolites and encrusted plant materials. These tufas form four facies associations that represent pisolitic intraclastic/lithoclastic oncoidal rudstones, phytohermal /bryophyte framestones, stromatolite-algal boundstones, and speleothem-like flowstones. These tufa associations were formed within a karstified carbonate terrain by a rainwater-fed paleospring system comprising waterfalls, slopes, dammed areas, lacustrines-paludal, and fluvial channel margin environments. Early diagenetic features are cementation, neomorphism and subaerial dissolution. Isotope-geochemical analysis indicated that the negative δ 18 O values (between-13.26 and-8.89‰ V-PDB) and the negative δ 13 C values (between-3.16 and-1.62‰ V-PDB) of the studied tufas are consistent with carbonates deposited from meteoric water in regions with much precipitation.
Resources Policy, Dec 1, 2022
International Journal of Earth Sciences, Feb 13, 2021
The tufa deposits are terrestrial carbonate rocks that are products of calcium carbonate precipit... more The tufa deposits are terrestrial carbonate rocks that are products of calcium carbonate precipitation from springs, fluvial streams, stagnant pools, water cascades, and shallow lakes (Pedley 1990, 2009; Ford and Pedley 2006). The tufas precipitate primarily from CaCO3-rich waters at ambient temperatures due to CO2 degassing and/or microbial and physiochemical activities (Pentecost 1985; Pedley 1990, 2009). The tufa deposits form a thin, surficial, soft, spongy, cellular or porous texture, semi-friable incrustation around the mouth of calcareous springs or seeps, or along fluvial streams carrying calcium carbonates (Chafetz and Folk 1984; Ford and Pedley 2006). The tufa deposits have been studied worldwide as their depositional, geochemical, and isotopic signatures can provide critical records of paleoenvironment and paleoclimatic conditions (Chafetz and Folk 1984; Ford and Pedley 2006; Andrews 2006; Pedley 2009). The Kurkur Oasis area in southern Egypt consists mainly of a thick sedimentary succession of Late Cretaceous–Quaternary age (Issawi 1968; Issawi and Sallam 2018). This succession is made up of the Nubia Formation (ConiacianSantonian) at the base, followed upward by the Dakhla Shale (Maastrichtian), Kurkur and Garra (Paleocene–Early Eocene), and Dungul (Early Eocene) formations, respectively. In the Kurkur Oasis area, the Quaternary tufa deposits are characterized by highly macrobiological components such as phytoherms such as plant stems, reeds, grasses and mosses (Fig. 1). Previous studies provide significant clues to the formation conditions of the Kurkur’s tufa deposits (Ahmed 1996; Crombie et al. 1997; Nicoll and Sallam 2017; Gaber et al. 2018; Sallam and Ruban 2019; Kele et al. 2018, 2020). For example, Issawi (1968) and Ahmed (1996) concluded that the tufa deposits in the Kurkur Oasis area were fossilized over different topographic levels. Some of these tufas were accumulated over 400 m a.s.l. erosional surface, whereas others were formed over 300 and 200 m a.s.l.. Structural controls affecting the development of Kurkur’s oasis tufas include fissure, cracks, and faults that would have enhanced groundwater recharge and emergence of carbonate-saturated springs (Nicoll and Sallam 2017). Jimenez (2014) assigned 76–246 ky to the lower tufa levels, while 514 ky to the higher tufa levels. Gaber et al. (2018) concluded that the older tufas in the Kurkur Oasis area were developed during warm pluvial periods, while the younger tufas were formed in drier conditions. Gaber et al. (2018) also suggested that the densely vegetated tufas were deposited along the shoreline of a lagoon. The sedimentary and geomorphological rarity of the paleospring tufa carbonates in the Kurkur Oasis area allowed Sallam et al. (2018) to recommend the creation of "Tufa World Geopark" which, in turn, will facilitate geotourism activities, geological heritage conservation, and sustainable socio-economic development in this area.
Доклады Академии наук Республики Таджикистан, 2010
Четвертичные отложения Обигармской впадины в своем распространении тесно связаны с рельефом и пре... more Четвертичные отложения Обигармской впадины в своем распространении тесно связаны с рельефом и представлены различными генетическими типами континентальных отложений: аллювиальные, озерные, пролювиальные и делювиальные. Они залегают на породах более древнего возраста, как правило, с резко выраженным угловым несогласием. Ключевые слова: четвертичные отложения-палеогеография-плейстоцен-литология лѐсс-палеопочвы-генезис-стратиграфические комплексы-Обигармская впадина. В сводном разрезе образований плейстоцена выделяются, в соответствии с рабочей схемой, четыре стратиграфических комплекса (снизу вверх): кулябский (Q 1 Kℓ), илякский (Q 2 iℓ), душанбинский (Q 3 db) и амударьинский (Q 4 ad). В рассматриваемом районе выделяются все четыре комплекса отложений, представленные континентальными образованиями (рис.). 1. Кулябский комплекс (Q 1 Kℓ). Кулябский комплекс характеризуется сильно изменчивым фациальным, литологическим составом пород и резко меняющейся мощностью. Обломочный материал пород, слагающих комплекс, чаще имеет местное происхождение, что обусловлено формированием этих осадков в локальных, нередко обособленных, понижениях древнего рельефа. Костные остатки млекопитающих, обнаруженные в отложениях этого комплекса, как в описываемом, так и в соседних районах, датируют возраст вмещающих пород верхним плиоценом-нижним плейстоценом [1-3]. Кулябский комплекс нижнечетвертичного возраста в описываемом районе выполняют Обигармскую впадину, слагают небольшие по площади участки в изученных частях долин рек Иляк, Даштирабат и Джавони. Обигармская впадина, возникшая в нижнечетвертичное время, ограничена на западе Гулизинданским, на востоке Дарайдегдонским разломами. Разрез характеризуемых образований в пойменной фации вскрыт саем Дешляшкар вблизи курорта Обигарм. Здесь на размытой поверхности палеозойских гранитоидов залегают лѐссовидно-суглинистые породы палево-коричневого цвета мощностью 50-60 м. Среди лѐссовидно-суглинистой породы имеются прослои (0.3-0.4 м) известняково-туфового состава. В основании пачки описываемых отложений имеется горизонт, содержащий костные остатки млекопитающих кошкурганского фаунистического комплекса, датируемые вмещающими породами как нижнечетвертичные [1]. Нижнечетвертичные образования на данном районе смяты в синклинальную складку. К приустьевой части сая Дешляшкар приурочено юго
Journal of Palaeogeography, 2022
Journal of African Earth Sciences
International Journal of Geoheritage and Parks
International Journal of Earth Sciences
1 Department of Geography, Faculty of Arts, Mansoura University, Mansoura, Egypt 2 Egyptian Envir... more 1 Department of Geography, Faculty of Arts, Mansoura University, Mansoura, Egypt 2 Egyptian Environmental Affairs Agency, Cairo, Egypt 3 Department of Geology, Faculty of Science, Benha University, Banha, Egypt The Eastern and Western deserts of Egypt are character‐ ized by a diversity of geoheritage sites that are attractive and promising for inventory, conservation and geotour‐ ism (e.g., Plyusnina et al. 2016; Mashaal et al. 2020; Sal‐ lam et al. 2018). The Dababiya Quarry, for example, is a unique palaeogeographical geosite located in the south Eastern Desert of Egypt, about 35 km southeast of the his‐ torical Pharaonic city of Luxor. The quarry is made up of sedimentary successions of Late Cretaceous–Quaternary age (Aubry et al. 2007). The Dababiya Quarry has a great stratigraphical significance because it exclusively includes the Global Standard Stratotype‐Section and Point (GSSP) for the Paleocene–Eocene boundary documented within the beds of the Paleocene–Lower Eocene Esna Shale (Aubry et al. 2007). The Esna Shale consists of four members, from base to top, El‐Hanadi, Dababiya Quarry, El‐Mahmiya and Abu Had members, and is overlain by the Lower Eocene Thebes Formation (Dupuis and Knox 2012). The Dababiya Quarry Member is typically composed of 3.68‐m‐thick lam‐ inated shale subdivided into five distinctive beds (b1–b5) that are representing the GSSP for the base of the Eocene Series (Dupuis et al. 2003) (Fig. 1). Nice denoting that the famous Pharaonic Temple of Hatshepsut in Luxor city was constructed in the upper part of the Esna Shale along the gradational boundary separating it from the overlying Lower Eocene Thebes Formation (Fig. 2). The Paleocene–Eocene transitional period was character‐ ized by an extreme global warming known in the literature as the “Paleocene–Eocene Thermal Maximum (PETM)” (Zachos et al. 2001). During this period, sea temperature increased significantly by a globally 5–8 °C warmth in less than 10 ka (Röhl et al. 2000). This global warming has eventually led to a major extinction of deep‐sea benthic foraminifera (Scheibner et al. 2005), calcareous nannofossils (Aubry 1998), diatoms (Oreshkina and Oberhänsli 2003), mammals (Clyde and Gingerich 1998), and evolutionary rejuvenations of planktonic foraminifera (Kelly et al. 1996). A widely accepted interpretation suggests that the initial deep‐sea warmth has led to a massive dissociation of oceanic methane hydrate‐triggered further warming (Dickens et al. 1995). Other related interpretations suppose an increase of volcanic eruptions and intrusion of mantle‐derived melts into carbon‐rich sediments in the northeast Atlantic Ocean (Svensen et al. 2004). Therefore, the information acquired from the Dababiya Quarry is very important for understand‐ ing the outstanding event of the PETM in the Earth’s history. This makes the Dababiya Quarry Geosite attractive to geo‐ science researchers and educators, and it can be designated as a palaeogeographical geosite of international rank (Sallam and Ruban 2017; Sallam et al. 2020).
The Quaternary sediments of Dashterabat hollow are developed mainly along the northern side of So... more The Quaternary sediments of Dashterabat hollow are developed mainly along the northern side of Sorkhco ridge, in the zone of Iliak fault and lie unconformably on Paleozoic granites. The formation of the Lower-Middle Quaternary sediments occurred in Lake Basin. On the basis of Radiocarbon age dating, the estimated age of uppermost part of Daraisalem section occurred within in the limit of 50980±550 years before present.
Arabian Journal of Geosciences
New investigations of petrographic and geochemical characteristics of Mesozoic sandstones from th... more New investigations of petrographic and geochemical characteristics of Mesozoic sandstones from the northwestern Gulf of Suez in Egypt have been undertaken, documenting dominance of quartzose sandstones containing on average ~ 5% of mostly sedimentary and subordinately metamorphic lithic fragments (siltstone, sandy siltstone, and, more rarely slate, metasiltstone, limestone, dolostone, quartz-muscovite schist, and gneiss). These sandstones are depleted in many chemical elements and display low Al2O3/SiO2 and K2O/Na2O ratios. Mineralogical and geochemical parameters point at extensive recycling from older (i.e., Paleozoic) siliciclastic strata. Relatively constant composition throughout the Mesozoic contrasts with successive palaeogeographic changes associated to the major events of rifting and dispersal, which may be explained by the widespread distribution of Paleozoic clastic wedges all across northern Gondwana.
International Journal of Earth Sciences
International Journal of Earth Sciences, 2021
A correction to this paper has been published: https://doi.org/10.1007/s00531-021-02042-8
International Journal of Earth Sciences
The Egyptian desert is known for its large number of geoheritage sites with regard to geomorpholo... more The Egyptian desert is known for its large number of geoheritage sites with regard to geomorphology, paleontology, sedimentology, geoarchaeology and palaeogeography (e.g.,
Journal of the Geological Society, 2020
The tufa deposits in the Kurkur–Dungul area, southern Egypt, date from marine isotope stage (MIS)... more The tufa deposits in the Kurkur–Dungul area, southern Egypt, date from marine isotope stage (MIS) 11 to MIS 1. Springs across the region were active during glacial periods (with sea-level below –50 m), reflecting changed atmospheric circulation over the Indian Ocean, as well as peak interglacial periods. During times of low sea-level, reduced Indonesian throughflow promoted formation of an Indian Ocean Warm Pool, and anomalous rainfall on its western margin. We suggest that Egypt lies at the intersection of westerly (‘maghrebian’) and easterly (‘mashriqian’) rainfall provinces, which show different timing with relation to orbital forcing and different source water regions. Tufa-growth periods are therefore not mechanistically linked to ‘humid periods’ or ‘sapropel events’ identified elsewhere. Stable isotope and T(Δ47) data are also inconsistent with these spring systems being part of a larger system spanning northern Africa, and lack a clear interaction between northern hemisphere ...
Table S1. Locations description.
Fig. S11. Age versus elevation.
Fig. S1. Generalized stratigraphy.
Table S3. Stable isotope microfacies and age data.
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Papers by Emad S . Sallam