Integration of remote sensing data with the field and laboratory investigation for lithological mapping of granitic phases: Kadabora pluton, Eastern Desert, Egypt

In the current study, an integration of Enhanced Thematic Mapper Plus (ETM+), field, and laboratory data have been used for lithological mapping of different granitic phases in the Kadabora area, Eastern Desert, Egypt. Application of enhancement techniques, including a new proposed band ratio combination (ratio 5/3, 3/1, 7/5 in RGB, respectively) and supervised classification images are used in discriminating different granitic phases in the Kadabora pluton from each other and from their environs. The data have been proved with the help of field and geochemical investigations. The results revealed that: (1) the Kadabora granitic pluton could be distinguished into three phases that recognized by field and laboratory investigation including granodiorite (phase I), monzogranite (phase II), and syeno-alkali feldspar granite (phase III). These phases are arranged according to their relative ages while the country rocks include ophiolitic mélange and metagabbro–diorite complex. It is also confirmed that the granitic pluton is invaded by dyke swarms which is trending in N–S direction. Geochemically, results show that the granodiorite is calc-alkaline, I-type and formed under subduction tectonic regime. Monzogranite falls within the alkaline and highly fractionated calc-alkaline granites, whereas syeno-alkali feldspar granite extends into proper alkaline granitoids field. Monzogranite and syeno-alkali feldspar granite belong to the A₂-subtype granite. This A₂-subtype granite was probably formed in an extensional regime, subsequent to subduction which can lead to tensional break-up of the crust (i.e., post-collisional, post-orogenic granites). The monzogranite and the syeno-alkali feldspar granite were probably formed by partial melting of relatively anhydrous lower crust source and/or tonalite to granodiorite is viable alternative to the granulite source.     

Experimental investigation of limestone of the Faiyah Range area,United Arab Emirates

The paper presents results of a laboratory experimental program performed on limestone rock samples, using both physical and mechanical methods. The studied rocks (Simsima Formation, Upper Cretaceous) can be classified as highly ferruginous and highly fossilliferous limestone. The lower part of the Simsima Formation contains common fauna such as Orbittoids, rhodolithic and rudists, whereas the upper part of the limestone is interbedded with conglomerates. Detailed geological, petrographic in addition to physical and mechanical tests were carried out on some representative samples from the Faiyah area, aiming at getting a better understanding of the important properties of these rocks. It is shown that the uniaxial unconfined compressive stress is the controlling factor of classification of the Faiyah limestone.     

Time dependent chemical study of contracting interstellar clouds. I. Abundances of nitrogen- and carbon-bearing molecules

We have constructed a reaction system containing the chemical families of H, C, O, N, S, Si, Cl, metals (Me) and grains. A total of 104 species have been included and a network of 557 reactions has been studied. The chemical kinetic equations were integrated as a function of time by using gear program. The chemical reaction system was followed at low, intermediate and high cloud densities i.e. from 10–10⁷ particles cm^-3. The calculated fractional abundances of N₂, CN, HCN, and CH which are in good agreement with the results of observations and with those of previous theoretical studies.     

The rosseland mean opacity of interstellar grains

We have calculated the opacity of interstellar grains in the temperature range 10–1500 K. Two composite grain models have been considered. One of them consists of silicate coated with an ice mantle and the second has a graphite core coated also with an ice mantle. These models are compared with isolated grain models. An exact analytical and computational development of Güttler's formulae for composite grain models has been used to calculate the extinction coefficient.It has been found that the thickness of the mantle affects the opacity of the interstellar grains. The opacity of composite models differs from that of the isolated models. The effect of the different species (ice, silicate, and graphite) is also clear.     

Detection and forecast of climate change effect on siltation using copulas

Theoretical and Applied Climatology - Being a subject of a worldwide growing importance, climate change and its impact on future water-management-solutions have become crucial to the planet’s...     

An objective Bayesian analysis of the change point problem

The Bayesian literature on the change point problem deals with the inference of a change in the distribution of a set of time-ordered data based on a sample of fixed size. This is the so-called retrospective or off-line analysis of the change point problem. A related but different problem is that of the sequential change point detection, mainly analyzed from a frequentist viewpoint. While the former typically focuses on the estimation of the position in which the change point occurs, the latter is a testing problem which has a natural formulation as a Bayesian model selection problem. In this paper we provide such a Bayesian formulation, which generalizes previous formulations such as the well-known CUSUM stopping rule. We show that the conventional improper priors (also called non-informative, objective or default), cannot be used either for sequential detection of the change or for retrospective estimation. Then, we propose objective intrinsic prior distributions for the unknown model parameters. The normal and Poisson cases are studied in detail and examples with simulated and real data are provided.