Middle Jurassic–Early Cretaceous foraminiferal biozonation of the Amran Group, eastern Sana’a Basin, Yemen

Two sections of strata assigned to the Amran Group at Jabal Salab and Jabal Yam in the eastern Sana’a governorate were sampled and correlated. These sections are part of a carbonate platform that extends from the city of Marib in the east to Naqil Ibn Ghailan, 20 km east of the city of Sana’a to the west. Palaeontological analysis of samples recovered has resulted in identification of 123 foraminiferal species, which are used to subdivide the sequence of the Amran Group into five biostratigraphic zones, aged between Bathonian (Middle Jurassic) and Berriasian (Early Cretaceous). The proposed biozones are those of Riyadhella rotundata, Kurnubia jurassica, Ammomarginulina sinaica, Alveosepta jaccardi and Pseudocyclammina sulaiyana/Furitilla caspianseis. These biozones were constructed and correlated with the equivalent zones reported from several localities

Porosity estimation in deep-water slope-channel system using seismic inversion model: A case study from the Nile Delta Basin, Egypt

The area of study is a Pliocene gas field, located in the Eastern portion of the West Nile Delta Deep Marine Concession (WDDM) offshore Egypt. The primary aim of this study is to establish a methodology for direct porosity estimate from 3D post-stack inversion (Zp) and assess its reliability. Porosity estimation from seismic inversion is a commonly used technique in geophysics to predict subsurface porosity from seismic data. Seismic inversion is the process of converting seismic reflection data into a quantitative representation of subsurface properties. Seismic inversion methods aim to relate the seismic response (amplitude, phase, frequency content) to rock properties such as porosity. The inversion process typically involves the following steps: Acoustic impedance inversion from seismic data is a widely utilized technique in reservoir characterization. In cases where well penetrations are limited, the resulting impedance section can be employed to predict reservoir parameters, including porosity. However, the relationship between acoustic impedance (AI) and porosity is influenced by the lithofacies and requires geological interpretation. To construct a porosity map and porosity static model, a comprehensive methodology was developed, capitalizing on the expected porosity volumes. By applying cut-offs to shear and acoustic impedance logs, categorical facies or fluid classes were established. The mean porosity for each lithofacies category is determined from the porosity logs of the wells under study. The inverted porosity model is validated against well log data or other independent measurements like core porosity to assess its accuracy and reliability. If necessary, additional adjustments or calibration may be performed to improve the porosity estimation. Subsequently, a final trend porosity volume was generated to estimate the porosity in areas distant from the study wells by establishing a correlation between average porosity values and acoustic impedance. This process of creating a porosity map will significantly mitigate drilling uncertainties going forward

抗腫瘍性トロポロン誘導体の創製と作用機序に関する研究

We image the lithospheric and upper asthenospheric structure of western continental Yemen with 24 broadband stations to evaluate the role of the Afar plume on the evolution of the continental margin and its extent eastward along the Gulf of Aden. We use teleseismic tomography to compute relative P wave velocity variations in south-western Yemen down to 300 km depth. Published receiver function analysis suggest a dramatic and localized thinning of the crust in the vicinity of the Red Sea and the Gulf of Aden, consistent with the velocity structure that we retrieve in our model. The mantle part of the model is dominated by the presence of a low-velocity anomaly in which we infer partial melting just below thick Oligocene flood basalts and recent off-axis volcanic events (from 15 Ma to present). This low-velocity anomaly could correspond to an abnormally hot mantle and could be responsible for dynamic topography and recent magmatism in western Yemen. Our new P wave velocity model beneath western Yemen suggests the young rift flank volcanoes beneath margins and on the flanks of the Red Sea rift are caused by focused small-scale diapiric upwelling from a broad region of hot mantle beneath the area. Our work shows that relatively hot mantle, along with partial melting of the mantle, can persist beneath rifted margins after breakup has occurred

Middle Jurassic–Early Cretaceous foraminiferal biozonation of the Amran Group, eastern Sana’a Basin, Yemen

Two sections of strata assigned to the Amran Group at Jabal Salab and Jabal Yam in the eastern Sana’a governorate were sampled and correlated. These sections are part of a carbonate platform that extends from the city of Marib in the east to Naqil Ibn Ghailan, 20 km east of the city of Sana’a to the west. Palaeontological analysis of samples recovered has resulted in identification of 123 foraminiferal species, which are used to subdivide the sequence of the Amran Group into five biostratigraphic zones, aged between Bathonian (Middle Jurassic) and Berriasian (Early Cretaceous). The proposed biozones are those of Riyadhella rotundata, Kurnubia jurassica, Ammomarginulina sinaica, Alveosepta jaccardi and Pseudocyclammina sulaiyana/Furitilla caspianseis. These biozones were constructed and correlated with the equivalent zones reported from several localities

Quality Evaluation of the Dewatering Subsurface Water in Urban Areas for Irrigation Purposes, Kuwait

The objective of this study is to assess the quality of the dewatered groundwater and identify its suitability for irrigation purposes in an urban study area by analyzing its chemical composition. The water quality for irrigation has been assessed by the determination of the residual sodium bicarbonate (RSBC), potential salinity (P.S), sodium adsorption ration, (SAR), Mg ratio (MgR), sodium percentage (%Na+), Kelly’s ratio (KR), permeability index (P.I), electrical conductivity, EC, total dissolved solids TDS, total hardness (TH), and pH. The WATEQ4F computer program has been used to compute the saturation indices of some minerals with respect to water composition. Gibb’s diagram is used to evaluate the functional sources of dissolved constituents. The chemical analyses reveal that the order abundance of the cation is as follows Na+ \u3e Ca2+ \u3e Mg2+ \u3e K+, and for anion is Cl-\u3e SO42- \u3e HCO3-. The chemical compounds in water, respectively, are Na2SO4, CaSO4 and NaCl. The groundwater exhibited oversaturation with respect to calcite and dolomite, and undersaturation with respect to gypsum, anhydrite, halite, brucite and magnesite. The geochemical processes of dissolution and precipitation are influenced the chemistry of the study area. The dewatered groundwater is consider good and safe for irrigation

Preliminary Assessment of Utilization of Al-Jaif Scoria (NW Sana’a, Yemen) for Cement Production

This paper presents the results of investigations on the potential industrial utilization of scoria, collected from Al-Jaif quarry, NW Sana'a, Yemen as a cement additive. Scoria was chosen as a cement additive material due to its availability and low cost from the Sana’a-Amran volcanic field in Yemen. The chemical composition of scoria was determined by X-ray fluorescence (XRF). The studied scoria is mainly composed of volcanic glass with a few zeolites (e.g. clinoptilolite) as revealed from petrographic investigation and X-ray diffraction (XRD). The scoria was added to the clinker in the range of 2, 4, 6, 8, 10 and 12% by weight. The fineness, surface area, water demand, setting time and compressive strength were conducted on scoria blended cement. According to experimental results, the high volcanic glass allows the addition of up to 12% scoria to the clinker to maintain a good potential of manufacturing blended cement. The results satisfy the European Standard EN requirements and confirm the viability of using scoria as a cement additive