The Faghur-Siwa Basin is a large sedimentary basin in the westernmost region of the Egyptian Western Desert. The northern portion of this basin has been hydrocarbon productive for the last few ...decades, making it a subject of frequent geological and geophysical studies. The current study aims to outline the subsurface extent, geometry and structural framework of Southern Faghur-Siwa Basin. The study introduces an approach of using large data set to deduce the structural setting of a sedimentary basin and its applicability to large-scale tectonic features in similar regions worldwide. This study uses satellite-derived potential field data, data of deep wells penetrating the basement, and previous geological studies. The Gaussian filter with a cut-off wave number of 0.0225 (Radian/km) was applied to study deep and shallow anomaly sources in the area while the edge detection methods were used to outline the subsurface boundaries of these sources. The 2.5D forward modeling of magnetic and gravity delineated the basin geometry and basement depth that ranges from 1200 to 5100 m. The basement structure map created by this study showed a complex subsurface structural framework of the Southern Faghur-Siwa Basin that is dominated by N–S, NNW-SSW, NE-SW, and E-W trending faults.
•Southern Faghur-Siwa Basin has an N–S axis, 500 km length, and 100–300 km width.•Mafic intrusions underlie the northern, eastern, and western parts of the basin.•Felsic igneous rocks underlie the central and southern parts.•2.5D gravity and magnetic models reveal basement depths ranging from 1200 to 5100m.•The basin is connected to Kufra Basin from the west and Abu Tarture Basin from east.
The salinization of the groundwater wells in Siwa oasis, Egypt represents a critical environmental and economic issue. Developing low-cost, effective, and self-supported inorganic membranes were ...suggested as suitable desalination techniques. Zeolite/geopolymer (Z/GP) membrane was synthesized as a potential low-cost membrane for effective desalination of brackish groundwater in Siwa Oasis, Egypt. The membrane was synthesized by simple geopolymerization for natural kaolinite and diatomite at room temperature. This was followed by hydrothermal growth of zeolite at 100 °C for 24 h to produce zeolitized geopolymer as potential inorganic membrane. After that, the prepared membrane was incorporated in the pervaporation desalination system considering the effect of the membrane thickness and the temperature. The results demonstrated water flux values of 8.34 kg.m−2.h−1, 7.63 kg.m−2.h−1, and 7.05 kg.m−2.h−1 for the tested membrane at thicknesses of 1 mm, 2 mm, and 3 mm, respectively. This associated with significant salt rejection prearranges 95.8% (1 mm), 97.6% (2 mm), and 99.4% (3 mm). Moreover, the high-temperature value (90 °C) is of strong positive impact on the water flux (7.82 kg.m−2.h−1) and a slight impact on the salt rejection (99.6%). The membrane is of significant stability considering the obtained water flux (7.51 kg.m−2.h−1) and salt rejection (99.57%) after 130 h. The reusability properties of the Z/GP membrane demonstrated its suitability to be used in the desalination process for five runs. Therefore, the synthetic Z/GP membrane is a highly recommended product for simple, effective, low cost, and available desalination technique brackish groundwater in Siwa Oasis.
•Zeolite/geopolymer membrane was used in the desalination of Siwa groundwater.•It achieved 7.82 kg.m−2.h−1 water flux and 99.6% salt rejection at 90 °C.•It is stable for 140 h with 7.5 kg.m−2.h−1 water flux and 99.57% salt rejection.•The membrane was reused for five runs with significant desalination performance.•The desalinated water matches the limitations of drinking and irrigation water.
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•There is a warming trend from the late Eocene to early Oligocene transition at Siwa Oasis.•The warming due to the high abundance of Operculina and occurrence of kaolinite and ...gypsiferous shale.•The release of mantle CO2 from volcanic episode starting in the late Eocene may cause this warming.
In the Eocene part of the Siwa Oasis, the larger foraminifera are represented by the genera Nummulites, Arxina, Operculina, Sphaerogypsina, Asterocyclina, Grzybowskia, Silvestriella, Gaziryina and Discocyclina in order of abundance. Operculina continues up to the early Oligocene as modern representatives in tropical regions, while the other genera became extinct. Nevertheless, the most common larger foraminiferal genus Lepidocyclina (Nephrolepidina) appears only in the lowermost Oligocene.
In spite of the Eocene–Oligocene (E/O) transition is thought to have been attended by major continental cooling at northern middle and high latitudes, we discover that at the Siwa Oasis, there is a clear warming trend from the late Eocene (extinction level of Nummulites, Sphaerogypsina, Asterocyclina, Grzybowskia, Silvestriella and Discocyclina) to the early Oligocene is observed due to the high abundance of Operculina and occurrence of kaolinite and gypsiferous shale deposits in both Qatrani and El Qara formations (Oligocene) at this transition. The El Qara Formation is a new rock unit proposed herein for the Oligocene (Rupelian age) in the first time.
Several episodes of volcanic activity occurred in Egypt during the Cenozoic. Mid Tertiary volcanicity was widespread and a number of successive volcanic pulses are starting in the late Eocene. The release of mantle CO2 from this very active volcanic episode may have in fact directly caused the warm Eocene–Oligocene greenhouse climate effect.
Water, it is said, will be the oil of the twenty-first century. Successful water management will be the key to future economic growth and social wealth in both developed and developing countries. Due ...to the continuous agricultural expansion, urban development, and increased demands on limited water supplies, Egypt is compelled to look for unconventional water resources. One of the most important sources is groundwater in the western desert of Egypt. More water abstraction is currently taking place raising the dangers of overexploitation and deterioration of water quality in Siwa Oasis located in Egypt western desert. The main objectives of this study are to monitor the quality of the Siwa Oasis groundwater over ten years. The present paper presents the results of this investigation and the future outlook for the situation of the limited water resources of the oasis. The data showed spatial differences between water qualities obtained from different locations within the Oasis. It was also observed that there are temporal changes and that water quality is deteriorating in alarming rate over time. Most studied water samples were considered unsuitable for irrigation due to salinity hazards. The reason that may contribute to speeding up groundwater quality deterioration is the unsafe ground water mining on the deep sandstone aquifers which causes the decreases of the fresh water vertical movement from the deep sandstone aquifer to the surface limestone aquifer.
Over the past two decades, environmental studies in research on prehistoric China have been gaining popularity and importance. For Northwest China in particular, climate change, especially the ...so-called ~4.2k BP event has been seen as the main reason for an alleged collapse of Late Neolithic societies and a transition to pastoral-heavy economies and mobile lifeways. Yet, these explanatory models tend to rely on limited archaeological and environmental data and non-contemporaneous historical data, resulting in simplistic causal relationships between environmental changes and social response. This paper re-evaluates the Incipient Bronze Age in China’s Northwestern region, discussing evidence for climate change and its exact dates, as well as textual and archaeological evidence. We argue that the old narratives perpetuating the image of a dichotomy between Steppe and Sown are inaccurate, while large-scale models of region-wide subsistence change in response to climate cooling tend to disregard local developments and group-specific responses as well as chronological issues. Focusing on the Xindian and Siwa archaeological phenomena, this paper provides a view into sub-regional responses to this climate event, warning against simplistic broad-brush reconstructions and calling for both a return to archaeological fundamentals and large-scale intensive fieldwork and interdisciplinary studies involving archaeologists, paleobotanists, zooarchaeologists, isotope specialists, and climate scientists.
Tourism planning and development is a complex, multifaceted, and highly politicised phenomenon, particularly in the context of economic development for rural minority communities. This paper ...discusses such a case in the context of a remote rural community, Siwa Oasis in the western desert of Egypt, which was one of the destinations identified in the development policy termed Infitāḥ, or "openness" in the early 1970s. As part of a long-term project, this article examines how community members perceive tourism development and its effects on their livelihoods, specifically from gender perspective. Findings show that the government development policy in effect resulted resulted in Siwan seeking to protect their identity, including values associated with traditional gender relations, where women are considered to be the safeguards of domestic duties, child-raising, and minority languages, providing empirical evidence on how development can be "closing" rather than "opening" opportunities, disempowering rather than empowering.
Two field experiments were conducted in two successive seasons; 2017 and 2018 at Bahi ElDin, Siwa Oasis, Egypt, to study the effect of four boron levels (0, 23, 46 and 69 ppm) as foliar application ...on yield and its components of five maize (Zea mays L.) hybrids (Single Crosses 124, 168, Three Way Crosses 310, 324 and 352). The experimental design was perpendicular strips plot with three replicates. Results indicated that effect of boron and hybrids on plant height, no. of grains/row, ear length, no. of rows/ear, ear diameter, 100-grain weight, grain, ear and stover yields (kg fed-1) were significant. Maize hybrid S.C. 124 produced the highest values of 100-grain wt., grain and ear yields per fed. Maximum no. of grains/row, ear length and stover yield fed-1 were recorded by TWC 324 hybrid. While, TWC 352 hybrid surpassed in no. of rows/ear and ear diameter. Foliar application by 69 ppm boron significantly produced more grains per row and ear, 100-grain wt. and grain yield/fed. Interactions were significant for all studied traits, except no. of grains/row and ear diameter. Thus, it could be concluded that applying 69 ppm boron as foliar for S.C.124 hybrid could be used successfully for improving maize productivity under Siwa Oasis conditions.
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