Relationships Among Hydraulic Characteristics Of The Dammam Aquifer And Wells In Kuwait

The Dammam Formation is a karstic aquifer in Kuwait that has a large range of transmissivity and, hence, productivity. The statistical analysis of 97 observations of transmissivity and specific capacity show the strong influence of outliers. A comparison of median values of these parameters indicates that the well field Shigaya C is the most productive and the Sulaibiya well field is the least productive. Logarithmic transformations of specific capacity and transmissivity show a positive linear relationship. Correlation between well losses for 47 wells with transmissivity and specific capacity does not indicate a definite trend; however, a positive log-linear relationship is indicated between well loss and the ratio of discharge and transmissivity. Logarithms of well loss constants show a negative linear relationship with logarithms of transmissivity and specific capacity. These relationships are useful for estimating hydraulic characteristics that are needed for the designs of wells and well fields and for preliminary water-resources evaluations. RÉSUMÉ: La formation de Damman au Koweit est un aquifére karstique qui présente une large transmissivité T et de coefficient d'emmagasinement S montre la forte influence des valeurs extrêmes. Une comparaison des valeurs de la méidane de ces paramètres montre que le champ captant de Shigaya C est le plus productif et que celui de Sulaubiya est le moins productif. Il existe une corrélation positive linéaire entre log T et log S. La corrélation entre les pertes en puits de 47 puits et T et S ne présente aucun lien significatif. Il existe cependant une relation positive log-linéaire entre pertes en puits et le rapport débit/transmissivité. De même, une relation négative log-linéaire est établie entre les pertes en puits et T et S. Ces relations sont utilisées pour estimer les caractéristiques hydrauliques de la formation à partir desquelles sont positionnés les puits et définis les champs captants et est basée l'évaluation préliminaire des ressources en eau. RESUMEN: La Formación Damman es un acuífero kárstico situado en Kuwait que presenta un amplio rango de transmisividades y, por tanto, de rendimientos. El análisis estadístico de 97 observaciones de transmisividad y capacidad específica muestra la gran influencia de valores anómalos. La comparación de valores medianos de dichos parámetros indica que el campo de pozos Shigaya C es el más productivo y que el Sulaibiya es el menos productivo. Las transformaciones logarítmicas de capacidad específica y transmisividad se relacionan linealmente de forma positiva. La correlación entre las pérdidas en los pozos con transmisividad y capacidad específica, a partir de datos en 47 pozos, no indican una tendencia definida; sin embargo, si se muestra una relación log-lineal positiva entre pérdidas en el pozo y la relación entre descarga y transmisividad. El logaritmo de las pérdidas en el pozo muestra una relación lineal negativa con los logaritmos de transmisividad y capacidad específica. Estas relaciones son útiles para estimar las características hidráulicas que son necesarias para el diseño de pozos y de baterías de pozos y para las evaluaciones preliminares de recursos hidráulicos.     

Oldest Basement (ca. 462 Ma) in Indonesian Borneo and its Implication for Early Paleozoic Tectonic Evolution of SE Asia

The lack of preserved basement results in uncertain placements of many terranes in Southeast Asia. Here, we flag the first evidence of the oldest basement in Indonesian Borneo, which can help locate terranes in Borneo on the northern margin of Gondwana in the early Paleozoic and explain the regional tectonic setting of the island. Two schist samples from the Embuoi Complex in the Semitau Block, Northwest Kalimantan yielded zircon U-Pb dates of 453.3 ± 1.9 Ma and 462.4 ± 2.6 Ma, respectively, representing the formation time of the protolith. Petrographic, internal structural and high Th/U ratios of zircons indicate that the protolith of schists is of magmatic origin. The zircons have εHf(t) values of ?4.1 to +1.1 and Hf model ages of 1.37–1.69 Ga, indicating they were derived from a mixed source of juvenile crust with old components. By comparison of zircon age distribution, two-stage Hf model ages and εHf(t) variations of the early Paleozoic igneous rocks from Semitau with those of South China, Tengchong–Baoshan, and Indochina, the Semitau Block was most likely a part of or placed next to the Indochina Block of northern Gondwana during the early Paleozoic. Such a similar tectono-magmatic pattern on northern Gondwana formed a prolonged early Paleozoic arc-related belt associated with subduction of the Proto-Tethyan Ocean.     

Application of the continuous wavelet transform on seismic data for mapping of channel deposits and gas detection at the CO2SINK site, Ketzin, Germany

Conventional seismic data are band limited and therefore, provide limited geological information. Every method that can push the limits is desirable for seismic data analysis. Recently, time‐frequency decomposition methods are being used to quickly extract geological information from seismic data and, especially, for revealing frequency‐dependent amplitude anomalies. Higher frequency resolution at lower frequencies and higher temporal resolution at higher frequencies are the objectives for different time‐frequency decomposition methods. Continuous wavelet transform techniques, which are the same as narrow‐band spectral analysis methods, provide frequency spectra with high temporal resolution without the windowing process associated with other techniques. Therefore, this technique can be used for analysing geological information associated with low and high frequencies that normally cannot be observed in conventional seismic data. In particular, the continuous wavelet transform is being used to detect thin sand bodies and also as a direct hydrocarbon indicator. This paper presents an application of the continuous wavelet transform method for the mapping of potential channel deposits, as well as remnant natural gas detection by mapping low‐frequency anomalies associated with the gas. The study was carried out at the experimental CO₂ storage site at Ketzin, Germany (CO₂SINK). Given that reservoir heterogeneity and faulting will have significant impact on the movement and storage of the injected CO₂, our results are encouraging for monitoring the migration of CO₂ at the site. Our study confirms the efficiency of the continuous wavelet transform decomposition method for the detection of frequency‐dependent anomalies that may be due to gas migration during and after the injection phase and in this way, it can be used for real‐time monitoring of the injected CO₂ from both surface and borehole seismics.     

Assessment of persistent organochlorine pollutants in sediments from Lake Manzala, Egypt

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were determined in surface and core sediment samples collected from Manzala Lake, the largest of the Egyptian coastal lakes. Total concentrations of OCPs and ∑7 PCBs (ICES) in sediments ranged from 0.63 to 31.31 ng/g and 0.26 to 31.27 ng/g, respectively. Geographical distribution indicates that levels of contaminants were significantly higher in areas which are mainly influenced by municipal discharge, indicating significant sources of these compounds in urbanised areas. The composition of DDT and its metabolites suggest old input of DDT. The levels of contaminants in Manzala Lake were similar or lower than those observed in comparable areas worldwide. The profiles of ∑OCPs and ∑PCBs in a core from a site heavily impacted by sewage discharge have highest concentrations in the surface core section indicating recent inputs. Assessment of ecotoxicological risk indicated that sediments in two sites were likely to pose potential biological adverse impact.     

Composition, age, and origin of the ~620?Ma Humr Akarim and Humrat Mukbid A-type granites: no evidence for pre-Neoproterozoic basement in the Eastern Desert, Egypt

The Humr Akarim and Humrat Mukbid plutons, in the central Eastern Desert of Egypt, are late Neoproterozoic post-collisional alkaline A-type granites. Humr Akarim and Humrat Mukbid plutonic rocks consist of subsolvus alkali granites and a subordinate roof facies of albite granite, which hosts greisen and Sn–Mo-mineralized quartz veins; textural and field evidence strongly suggest the presence of late magmatic F-rich fluids. The granites are Si-alkali rich, Mg–Ca–Ti poor with high Rb/Sr (20–123), and low K/Rb (27–65). They are enriched in high field strength elements (e.g., Nb, Ta, Zr, Y, U, Th) and heavy rare earth elements (La _n /Yb _n ?=?0.27–0.95) and exhibit significant tetrad effects in REE patterns. These geochemical attributes indicate that granite trace element distribution was controlled by crystal fractionation as well as interaction with fluorine-rich magmatic fluids. U–Pb SHRIMP zircon dating indicates an age of ~630–620?Ma but with abundant evidence that zircons were affected by late corrosive fluids (e.g., discordance, high common Pb). εNd at 620?Ma ranges from +3.4 to +6.8 (mean?=?+5.0) for Humr Akarim granitic rocks and from +4.8 to +7.5 (mean?=?+5.8) for Humrat Mukbid granitic rocks. Some slightly older zircons (~740?Ma, 703?Ma) may have been inherited from older granites in the region. Our U–Pb zircon data and Nd isotope results indicate a juvenile magma source of Neoproterozoic age like that responsible for forming most other ANS crust and refute previous conclusions that pre-Neoproterozoic continental crust was involved in the generation of the studied granites.     

Temporal and spatial distribution of dissolved Cu, Ni and Zn in the coastal waters of Jeddah, eastern Red Sea

Dissolved Cu, Ni, and Zn were measured in the surface coastal waters of Jeddah, eastern Red Sea during October 2004 and April 2005. High values of trace metals, particularly Zn, were recorded in the Southern Corniche area close to a sewage effluent indicating a significant contribution from the wastewater. Concentrations of trace metals decreased northward and southward under the effect of dilution. Another hot spot was also observed in the vicinity of Jeddah Desalination Plant (JDP) during April 2005 indicating a possible contribution from the JDP to trace metal contents in the study area. Trace metals were correlated to salinity, nutrients and particulate organic carbon (POC). The good association between Zn and reactive silicate and Ni and ammonium is attributed to simultaneous biological utilization and regeneration. The behavior of copper suggested adsorption of Cu onto the POC during October 2004 whereas in April 2005 the most important process seems to be desorption of Cu from the particulate materials.     

Assessment of the mutual impact between climate and vegetation cover using NOAA-AVHRR and Landsat data in Egypt

The objective of the current study is to use satellite data to assess the mutual influence between vegetation and climate. The Ismailia Governorate was selected as a case study to investigate the impact of vegetation cover expansion on both land surface and air temperature from 1983 to 2010 and vice versa. This observation site was carefully selected as a clear example of the high rate of the reclamation and vegetation expansion process in Egypt. Land surface temperature (LST) was estimated through the Advanced Very High Resolution Radiometer (a space-borne sensor embarked on the National Oceanic and Atmospheric Administration) data while air temperature (T _air) was collected from ground meteorological stations in the study area. Irrigated agriculture is the largest consumer of freshwater resources. However, consistent information on irrigation water use is still lacking. Relative humidity, wind speed, solar radiation, and T _air data were inserted in the Penman–Monteith equation to calculate potential evapotranspiration (ET_o), while both LST and T _air were used to observe the relative water status of the study area as a result of the water deficit index (WDI). Then, both WDI and ET_o were used to calculate actual evepotranspiration (ET_C.). The results showed that LST decreased by about 2.3 °C while T _air decreased by about 1.6 °C during the study period. The results showed also that the vegetation cover expanded from 25,529.85 ha in 1985 to 63,140.49 ha in 2009 with about 147 % increase. This decrease in LST and air temperature was according to the expansion of the cultivated land that was proved through the processing of three Landsat TM and Landsat ETM+ imageries acquired in June 19, 1985, June 7, 1998, and June 29, 2009. The vegetation water consumption was affected by the decreasing surface and air temperature. The results showed that the water deficit index decreased by about 0.35, and actual evapotranspiration increased by about 2.5 mm during the study period.     

Seismic hazard and probability assessment of Kashmir valley,northwest Himalaya,India

Seismic hazard analysis of the northwest Himalayan belt was carried out by using extreme value theory (EVT). The rate of seismicity (a value) and recurrence intervals with the given earthquake magnitude (b value) was calculated from the observed data using Gutenberg–Richter Law. The statistical evaluation of 12,125 events from 1902 to 2017 shows the increasing trend in their inter-arrival times. The frequency–magnitude relation exhibits a linear downslope trend with negative slope of 0.8277 and positive intercept of 4.6977. The empirical results showed that the annual risk probability of high magnitude earthquake M?≥?7.7 in 50 years is 88% with recurrence period of 47 years, probability of M?≤?7.5 in 50 years is 97% with recurrence period of 27 years, and probability of M?≤?6.5 in 50 years is 100% with recurrence period of 4 years. Kashmir valley, located in the NW Himalaya, encompasses a peculiar tectonic and structural setup. The patterns of the present and historical seismicity records of the valley suggest a long-term strain accumulation along NNW and SSE extensions with the decline in the seismic gap, posing a potential threat of earthquakes in the future. The Kashmir valley is characterized by the typical lithological, tectono-geomorphic, geotechnical, hydrogeological and socioeconomic settings that augment the earthquake vulnerability associated with the seismicity of the region. The cumulative impact of the various influencing parameters therefore exacerbates the seismic hazard risk of the valley to future earthquake events.     

Exploration of copper deposits in Wadi El Regeita area, Southern Sinai, Egypt, with contribution of remote sensing and geophysical data

Three types of hydrothermal alterations are recorded in Wadi El Regeita area, argillic, phyllic, and propylitic. Whole-rock analysis of representative samples of the alteration halo (1) shows a Cu, Au, and Ag content up to 1.7 wt.%, 1.6 g/t, and 4 g/t, respectively; in the alteration halo (2), these metal contents are up to 1.3 wt.%, 1.4 g/t, and 3 g/t, following the same order. The integrated remote sensing and geophysical data, as well as geological field verification, show that Wadi El Regeita area includes promising Cu ores within two hydrothermal alteration haloes. Spatial data analyses of lineaments from Landsat Enhanced Thematic Mapper (ETM) band ratio image (7/5, 5/4, 3/1) reveal the presence of alteration haloes that potentially may host Cu mineralization at south and north of El Regita Cu mine. Gravity interpretation indicates that the surveyed area is dissected by NE–SW fault zones in the central part, near Wadi El Regeita Cu mine. Ground magnetic survey data revealed that the surveyed area includes six magnetic bodies at depths ranging from 32 to 90 m, possibly recording the presence of mineralized and hydrothermally altered andesitic dykes. The half length of these dykes ranges from 600 to 1,070 m; their half thickness from 30 to 123 m and their half width from 48 to 531 m. Dyke locations coincide with surface alteration haloes (1) and (2) as indicated by the ETM band ratio image processing. The final assessment of the area, however, needs more detailed geological and geophysical studies with contributions of remote sensing techniques.