Selection of the best fit probability distribution in rainfall frequency analysis for Qatar

Natural Hazards - Design rainfall is widely used in urban infrastructure planning and design such as culverts and urban drainage systems. In design rainfall estimation, one of the primary steps is...     

Changes in the Virtual Dipole Moment of the Earth’s Magnetic Field in the Phanerozoic

Data on the virtual dipole moment (VDP) is distributed nonuniformly with time, which significantly complicates qualitative and quantitative analysis of its evolution. In addition to the moving average method and median values, for the first time, a technique is presented for a quasi-uniform presentation of data (interpolation method), as well as results of calculating the evolution of the VDM by this method for the Phanerozoic.     

Age of the Scan Basin (Scotia Sea)

Integrated geological and geophysical analysis of the anomalous magnetic field along with the previously unpublished profiles of Spanish expeditions onboard the R/V Hesperides and international databases of geomagnetic data processed in the context of the global tectonics concepts made it possible to identify paleomagnetic anomalies C11–C15 and compile the first map of the bottom geochronology of the Scan Basin. Unlike in earlier known publications, the paleoaxis of spreading does extend northeast, but approximately at an angle of 345°. According to calculations, spreading began 35.294?35.706 Ma ago during chron C15r, and the spreading paleoaxis was abandoned 29.527?29.970 Ma ago during chron C11n.2n. Thus, the destruction of the American–Antarctic bridge in the region joining the Bruce and Discovery banks with formation of oceanic crust in the Scan Basin started about 36 Ma ago. Regular spreading of the bottom has been continuing for about 6 Ma at a average rate close to 1.8 cm/year.     

Kinematic model of the opening of the Canadian Basin, Arctic Ocean

The initial configuration of the Arctida Craton was reconstructed from a complex geological-geophysical analysis of the anomalous magnetic field of the Canadian Basin in the Arctic Ocean. The modern version of the bottom geochronology indicates that the first stage of the formation of the Canadian Basin in the Arctic Ocean was related to extension and rifting in the Arctida Craton in the Kimmeridgian. The transformation of rifting into spreading presumably occurred during chron M22Ar (151 Ma). The second stage was related to the opening of the Canadian Basin within chrons M22Ar-M19 (151–145 Ma). The next stage of the opening of the basin was marked by a 100-km jump of the spreading axis to the east. This stage ended after chron M5 (130 Ma ago). At the fourth (Late Cretaceous) stage, extension spanned the Southern Canadian Basin with the formation of large igneous province.     

Water demand management in Yemen and Jordan: addressing power and interests

This paper investigates the extent to which entrenched interests of stakeholder groups both maintain water use practice, and may be confronted. The focus is on the agricultural sectors of Yemen and Jordan, where water resource policymakers face resistance in their attempts to reduce water use to environmentally sustainable levels through implementation of water demand management (WDM) activities. Some farmers in both countries that have invested in irrigated production of high-value crops (such as qat and bananas) benefit from a political economy that encourages increased rather than reduced water consumption. The resultant over-exploitation of water resources affects groups in unequal measures. Stakeholder analysis demonstrates that the more ‘powerful’ groups (chiefly the large landowners and the political elites, as well as the ministries of irrigation over which they exert influence) are generally opposed to reform in water use, while the proponents of WDM (e.g. water resource managers, environmental ministries and NGOs, and the international donor community) are found to have minimal influence over water use policy and decisionmaking. Efforts and ideas attempted by this latter group to challenge the status quo are classified here as either (a) influencing or (b) challenging the power asymmetry, and the merits and limits of both approaches are discussed. The interpretation of evidence suggests current practice is likely to endure, but may be more effectively challenged if a long-term approach is taken with an awareness of opportunities generated by windows of opportunity and the participation of ‘overlap groups’.     

Assesing the effect of an olive mill wastewater evaporation pond in Sousse, Tunisia

Olive oil is a typical and valuable agro-industrial product in Mediterranean countries. In Tunisia, olive mill wastewaters (OMW) reach an amount of about 1,000,000 t year⁻¹ and constitute a serious organic pollution risk because of the high chemical oxygen demand values and the presence of phytotoxic and antibacterial polyphenols. OMW have been generally stored in pond sites to be eliminated by natural evaporation or valorised by spreading on cultivated soils or by composting. Many researches on the interactions of OMW with soils at laboratory scale (columns) have been reported, but less attention have been paid to the effect of OMW on soils at field scale. The aim of this work is to investigate an area used for >15 years as an uncontrolled OMW pond site. The transformations of soil properties and groundwater occurring during OMW storage were characterised by the pH, phenolic contents, electrical conductivity (EC), moisture content and organic contents. The soil samples were taken from two borings and compared to those of a control one located near the pond site. Groundwater samples were taken on the accessible and nearest water wells to the evaporation ponds. The permeable silty and sandy layers in the site support the infiltration of OMW near the evaporation ponds. This infiltration has reached a depth of 6 m at a distance of almost 50 m laterally. The results show that the OMW infiltration in the subsoil has affected the pH, EC, organic content, phenolic compounds and the moisture.     

The Wajid Sandstone around Abha/Khamis Mushayt and in its type area: lithostratigraphic architecture and correlations

The Wajid Sandstone of southeastern Saudi Arabia is a prolific aquifer and a recent target for hydrocarbon exploration, but a sedimentologic model and the stratigraphic architecture of the sediments have only recently been presented for the type area of the Wajid Group around Wadi Dawasir. Farther to the west, the Wajid Sandstone was also recognized, but stratigraphic architecture and sedimentology are poorly known. This paper presents the preliminary results of investigations targeted at the outcrops west and south of the type area, covering the area between Wadi Dawasir, Najran in the south, and Abha in the west. Two successions are recognized, a lower red one and an upper beige one. Although the lower one sedimentologically shares several features with the lowermost unit in the type area, the marine Dibsiyah Formation, a correlation remains doubtful. The red succession lacks the Skolithos fauna of the Dibsiyah Formation, and its facies associations point to a fluvial depositional environment. From its stratigraphic position and from its lithology, the red succession is similar to the Siq Formation of the northern Kingdom and it will be discussed whether the red succession might be a yet unrecognized equivalent of the Siq Formation. The lower red unit is bounded by a major unconformity, separating it from the underlying basement. This pan-African unconformity developed during a latest Neoproterozoic–Cambrian episode of intensive weathering and peneplanation. It is characterized by a thick weathering zone and an overlying coarse but thin quartz pebble breccia to conglomerate, which together represent a regolith. The beige succession is definitely correlated to the Khusayyayn Formation. Both successions are characterized by macro-scale to giant 2D and 3D submarine dunes and share many other phenomena. The basal unconformity also shows regolith development with a quartz pebble conglomerate, whose clasts seem to have been reworked from the pan-African regolith.     

古新世特提斯北缘前黑海地区盆地的演化与油气远景

此文为研究特提斯北缘前黑海地区盆地地质发展史的成果。结论是：携带有北方大陆碎屑物质的河流是其沉积作用中的主要因素。油气远景与古河流扇影响的地带有关，在那些地带出现碎屑储层的斜坡沉积。这已为古顿河—库班河和古多脑河—第聂伯尔河先三角洲的大量野外发现所证实。