Petrology, Geochemistry, Petrogenesis and Reactivation of Volcanic Tuffs at Dair El-Kahif Area, NE-Jordan

The volcanism in the western Arabian plate extends from the Red Sea through the Harrat Ash-shaam system to western Syria. The aforementioned volcanic activity produced large quantities of alkali olivine basalts and tuffaceous materials. The stratovolcano (7km) NE of Dair El-Kahif, NE Jordan has been investigated. The results show that dominant mineral phases are olivine, augite, plagioclase, magnetite and ilmenite. Chemical analysis of the whole rock tuff samples confirms alkali olivine magma origin. Low concentrations of Li and Rb in tuff samples are used as an argument against the contamination of the basaltic magma during its journey to the surface. The MgO and Mg-values (Mg/Mg+Fe²+) in samples from volcanic tuff exhibit different degrees of fractionation, which are indicated by the varying concentrations of incompatible trace elements (Ba, Rb, Sr). The thermometric evaluation of tuff determined by using pyroxene thermometers revealed a temperature range between 1022-1083°C and a pressure of 5-10 kbars. The low Mg-ratio (Mg/Mg+Fe²+) is due to fractional crystallization of olivine and pyroxene in tuff samples. The variations of incompatible elements imply derivation from a peridotite source in the upper mantle with low degree of melting (<20%). The volcanic activity took place in phases corresponding to rifting associated with the sinistral movement along the Dead Sea Transform and the later reactivation processes

Developing a Land Suitability Index for Agricultural Uses in Dry Lands From Geologic Point of View Using GIS - a Case Study From Jordan

DOI:10.17014/ijog.2.2.63-76In the context of the study, a Multi-criteria evaluation (MCE) in GIS was used in developing suitability index to optimize suitable lands for agricultural uses and seasonal farming in dry lands from geologic point of view. This study was performed in the areas between Mafraq and Zarqa Cities in Jordan which are classified as arid lands. The study aims at protecting groundwater from pollution, reducing soil salting, reducing irrigation water loss caused by evaporation, and increasing crop productivity. The geo-environmental parameters of the named area including geology, groundwater depths, soil depths and textures, climatic conditions, topographic settings, and groundwater vulnerability conditions were mapped and converted into layers with special rates, given weights, and then modeled using the multi criteria evaluation (MCE) option, using Decision Making Modeling in IDRISI (GIS software) to reach at the best choice of lands for agricultural activities, and also to determine which of these lands are suitable for summer farming and which are suitable for winter farming

Developing a Geoinformatic-engineering Stability Modeling Method, Using Field Data and GIS Environment: a Case Study From Al Qarara Area in Wadi Musa, Jordan

DOI:10.17014/ijog.2.1.1-21By applying detailed geological field surveys, the spatial factors affecting geo-engineering stability were used to develop a geo-engineering stability modeling method to identify areas under potential threat of landsliding. The factors affecting geo-engineering stability in Al Qarara area in Petra-Jordan were studied and given assumed rates of importance, where optimization process was run by lag iterations; the produced spatial layers of the different factors were gathered and modeled using GIS; a final stability map was produced using an optimized equation. The produced map was validated qualitatively and quantitatively, where a comparison was made between the reality in the field and several maps of different equation. The modeling method which was developed in the context of this study proved to be suitable to produce micro-zonation maps of areas having landslide risk. Further applications on the method in other areas suffering landslides will further improve it