Hydrological structure of waters of the persian gulf according to the data of observations in 1992

We describe the hydrological structure of waters of the Persian Gulf and its seasonal variability according to the data of CTD surveys carried out in February–June 1992 in the course of the cruises of the NOAA R/VMt. Mitchell aimed at the analysis of the consequences of the ecological catastrophe caused by the spread of oil spots formed as a result of war operations in the Persian Gulf in 1991. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Air quality and elemental enrichment factors of aerosol particulate matter in Riyadh City, Saudi Arabia

Air particulate matter (PM) samples were collected from June 2006 to May 2007 for determination of chemical elements. PM samples were taken in two size fractions (PM_2.5 and PM₁₀) with MiniVolume air samplers on rooftops of various buildings (15–25 m above ground) in the city of Riyadh. The samples were subjected to X-ray fluorescence analysis to measure major (Na, Mg, Al, K, Ca, Si, P, S, and Fe) and trace elements (Mn, Ni, Cu, Zn, and Ba). The results showed that the PM concentrations were higher for PM₁₀ compared to PM_2.5, indicating that the major PM source was local dust. Also the spatial distribution with high PM concentrations was observed in the south and southeast of the city and the lowest levels were in the center and northeast of the city. This spatial distribution was attributed to different factors such as wind direction and velocity, emission from cement factories, and the presence of buildings, trees, and paved streets that reduce the amount of dust resuspended into the atmosphere. The air quality of the city was found to range from good to hazardous based on PM_2.5, and from good to very hazardous based on PM₁₀. The element-enrichment factors revealed two element groups according to their changing spatial behavior. The first group showed no significant spatial changes indicating they have the same common source. The second group (mainly S and Ni) exhibited significant changes as expected from anthropogenic inputs. The origin of S is possibly a combination of minerals (CaSO₄) and fossil fuel combustion. The source of Ni is probably from fossil fuel combustion.     

Deep hydrothermal activity in hydrocarbon reservoirs,South Kuwait

Fluid inclusion (FI) data provide insights into the origin of hot fluids in Cretaceous and Jurassic reservoirs in south Kuwait. FI data for Cretaceous reservoirs show anomalously high temperatures exceeding 200 °C compared to samples from the Jurassic. In addition, formation water chemical geothermometry data also show anomalous water-rock equilibration temperatures. The preservation of high temperatures indicates rapid migration from depth through deep-seated fault systems. This implies that very hot fluids probably migrated up-fault from near basement to the Cretaceous section. This approach helps to understand the role of hydrothermal activity associated with basement faults in south Kuwait.     

Meteorites from the United Arab Emirates: Description,weathering, and terrestrial ages

We report on the first meteorite search campaign in the United Arab Emirates (UAE). The geology and proximity of our search region suggest that it is the north‐western extension of the Oman meteorite fields. We found 26 ordinary chondrites, bringing the total number of official meteorites from the UAE to 28. The campaign was organized and conducted in close cooperation with the UAE government and the main masses of the meteorites remained in the country where they will become part of an exhibition. The bulk composition of five meteorite and three soil samples indicates an uptake of U, Mo, Sr, Ba, Li, and Pb from the soil into the meteorites during terrestrial weathering. Terrestrial ages determined from ¹⁴C decay of 21 meteorites range from recent falls to 24.4 ka, with two meteorites having >37 ka and approximately 39 ka, respectively. Weak correlations between weathering degree, meteorite bulk chemical composition, and terrestrial age suggest highly localized weathering conditions, possibly related to abundant occurrences of sabkhas in the search region.     

Application of formation water geochemistry to assess seal integrity of the Gotnia Formation,Kuwait

A very large database of formation water geochemistry has been acquired for the Kuwait petroleum system. This database makes it possible to explore the geological history of Kuwait’s formation and ground waters in a way that is not possible by other means. Working at this regional scale spatial and formational variation in groundwater chemistry in Kuwait identifies lithostratigraphy and physical barriers to flow that can be explored in the context of Kuwait’s geological history. Cretaceous oil reservoirs in north Kuwait have formation water saturated with Na (>50%) that is anomalously abnormal in salinity for its depth. The most likely subsurface source of such saline water is the Upper Jurassic Gotnia Formation which comprises beds of evaporite halite, and/or pre-Gotnia formations of deeper reservoirs. To reach their current location, both parts of the Gotnia and Hith formations must have been breached. To date, this is the only evidence to show that the sealing capacity of the Gotnia Formation has been overcome, implying that the formation, and therefore units beneath, are capable of sourcing fluids to younger and shallower reservoirs. Given the ubiquity of samples of formation water in many other regions, applying formation water geochemistry to other petroleum systems would appear a good method for evaluating basin models and understanding of fluid migration in mature petroleum provenances.     

Effect of the plume rise and wind speed on extreme value of air pollutant concentration

Summary Extreme values of the ground level concentration of air pollutants were evaluated as a function of plume rise Δh, and wind speed in two cases. Firstly, when a plume rise depends on the downwind distance x, and secondly, with a constant plume rise (i.e., independent on x). Also, the extreme values for the effective stack height were evaluated for different stability classes. The maximum value of the ground level concentration was obtained in unstable stability when plume rise depends on x and in the neutral stability when plume rise independent on x. Also, in stable case, the extreme values of the ground level concentration of air pollutants showed similar values in the two cases when plume rise depends on x, and with constant plume rise. Finally, it was found that the extreme value of the ground level concentration occurred near the stack and after that it was decreases in all stabilities.     

Subsidence et effondrements le long du littoral jordanien de la mer Morte : apports de la gravimétrie et de l'interférométrie radar différentielle

The Dead Sea shore is affected by major subsidence and sinkholes hazards due to the decrease of the sea level. The frequency of resulting accidents increased during the last four decades. Those phenomena could be at the origin of the catastrophic destruction of a major salt evaporation pond on 22 March 2000. In this paper, we show the main results of eight years of research in gravimetry and radar interferometry devoted to identify potentially hazardous areas, at different scales along the Jordanian Dead Sea coast, from the metric scale (gravimetric approach) to the kilometric one (interferometric approach). To cite this article: D. Closson et al., C. R. Geoscience 335 (2003).     

Analysis of early late phase in single-and dual-frequency GPS receivers for multipath detection

Much of the research into multipath detection and mitigation has not considered the carrier phase delay between the line of sight (LOS) and reflected signals. A new variable referred to as early late phase (ELP) has recently been proposed to exploit this phase difference. It has been found that in a receiver tracking the L1 GPS signal, the probability of detecting multipath is lower when the carrier phase difference between the LOS and a reflected signal is an integer multiple of π. Since the pseudorange error caused by the multipath’s presence is the highest in this case, we propose to exploit the coexistence of another GPS civilian signal, the L2C. We present an analysis of ELP for the L1 and L2C signals, and a combination of both, for detecting multipath. The multipath detection performance has been compared using probabilities of false alarm and detection. An ideal algorithm should have lower probability of false alarm and higher probability of detection. However, it has been found that using dual-frequency ELP increases both probabilities. Thus, receiver operator characteristics (ROC) curves, and the area under the ROC curves, have been used for effective comparison. It has been found that the L2C signal individually gives worse performance than L1 because of its weaker signal strength. However, the combination of L1 and L2C gives the best overall performance, and thus it can be claimed that ELP using dual-frequency receivers is a more effective approach for detecting multipath.