Provenance,weathering, and paleoenvironment of the Upper Cretaceous Duwi black shales,Aswan Governorate,Egypt

The mineralogy and geochemistry of the Upper Cretaceous Duwi black shales of Nile Valley district, Aswan Governorate, Egypt, have been investigated to identify the source rock characteristics, paleoweathering, and paleoenvironment of the source area. The Duwi Formation consists mainly of phosphorite and black shales and is subdivided into three members. The lower and upper members composed mainly of phosphorite beds intercalated with thin lenses of gray shales, while the middle member is mainly composed of gray shale, cracked, and filled with gypsum. Mineralogically, the Duwi black shales consist mainly of smectite and kaolinite. The non-clay minerals are dominated by quartz, calcite, phosphate, dolomite, feldspar, with little gypsum, anhydrite, iron oxides, and pyrite. Based on the CIA, PIA, and CIW values (average?=?84, 94, 95, respectively), it can be concluded that the litho-components of the studied shales were subjected to intense chemical weathering and reflect warm/humid climatic conditions in the depositional basin. The provenance discrimination diagram indicates that the nature of the source rocks probably was mainly intermediate and mafic igneous sources with subordinate recycled sedimentary rocks (Nubia Formation). Geochemical characteristics indicate that the Duwi black shales in Nile Valley district were deposited under anoxic reducing marine environments.     

Comparison between VES and 2D imaging techniques for delineating subsurface plume of hydrocarbon contaminated water southeast of Karbala City,Iraq

Shallow vertical electrical sounding (VES) technique with Schlumberger electrode array (maximum distance between current electrodes was 50 m) through 25 VES points distributed on five traverses. Two 2D imaging lines with Wenner electrode array 30 m each corresponding to two VES traverses were conducted near well water contaminated with hydrocarbon materials at Karbala Governorate, Iraq. It is found that these techniques can give good results in delineating contaminated and clear zones but the 2D imaging technique was better in delineating the boundaries of the contaminated water plume and gave clear image of the subsurface distribution of the contaminated water vertically and horizontally.     

Mapping cropland fallow areas in myanmar to scale up sustainable intensification of pulse crops in the farming system

Cropland fallows are the next best-bet for intensification and extensification, leading to increased food production and adding to the nutritional basket. The agronomical suitability of these lands can decide the extent of usage of these lands. Myanmar’s agricultural land (over 13.8 Mha) has the potential to expand by another 50% into additional fallow areas. These areas may be used to grow short-duration pulses, which are economically important and nutritionally rich, and constitute the diets of millions of people as well as provide an important source of livestock feed throughout Asia. Intensifying rice fallows will not only improve the productivity of the land but also increase the income of the smallholder farmers. The enhanced cultivation of pulses will help improve nutritional security in Myanmar and also help conserve natural resources and reduce environmental degradation. The objectives of this study was to use remote sensing methods to identify croplands in Myanmar and cropland fallow areas in two important agro-ecological regions, delta and coastal region and the dry zone. The study used moderate-resolution imaging spectroradiometer (MODIS) 250-m, 16-day normalized difference vegetation index (NDVI) maximum value composite (MVC), and land surface water index (LSWI) for one 1 year (1 June 2012–31 May 2013) along with seasonal field-plot level information and spectral matching techniques to derive croplands versus cropland fallows for each of the three seasons: the monsoon period between June and October; winter period between November and February; and summer period between March and May. The study showed that Myanmar had total net cropland area (TNCA) of 13.8 Mha. Cropland fallows during the monsoon season account for a meagre 2.4% of TNCA. However, in the winter season, 56.5% of TNCA (or 7.8 Mha) were classified as cropland fallows and during the summer season, 82.7% of TNCA (11.4 Mha) were cropland fallows. The producer’s accuracy of the cropland fallow class varied between 92 and 98% (errors of omission of 2 to 8%) and user’s accuracy varied between 82 and 92% (errors of commission of 8 to 18%) for winter and summer, respectively. Overall, the study estimated 19.2 Mha cropland fallows from the two major seasons (winter and summer). Out of this, 10.08 Mha has sufficient moisture (either from rainfall or stored soil water content) to grow short-season pulse crops. This potential with an estimated income of US$ 300 per hectare, if exploited sustainably, is estimated to bring an additional net income of about US$ 1.5 billion to Myanmar per year if at least half (5.04 Mha) of the total cropland fallows (10.08 Mha) is covered with short season pulses.     

Urban form study: the sprawling city—review of methods of studying urban sprawl

There is a large body of research on urban forms. This review paper focuses on the urban sprawl using new and old approaches and new techniques from the subfield of urban Geography. There has been a debate among researchers about the definition of the sprawl, which makes it difficult to suggest a reliable model of the urban sprawl. This review is extremely selective. Numerous papers have focused on measuring the in terms of its physical cost or the environmental and transportation measures linked to this phenomenon. Several attempts have been made to improve the measurement of the sprawl using new approaches. Furthermore, this paper show that certain researchers did not attempt to explore new methods to investigate the urban sprawl in the past and present overlay layers for many years, researchers may use cartography techniques, for example, thereby collecting 20 years of data to match layers and show the differences in any metropolitan area. Several problems remain like differences in the understanding of the sprawl among planners and between other researchers interested in this issue. Also, it is problematic to find one measure, such as mixing different measures together to distinguish between car density and resident density. This study evaluated and reviewed old and recent studies to show that the most important issue in the urban sprawl relates to measurements. Incorporates inform and which measure is best. This article argues that urban spatial expansion reviews some of articles written on urban sprawl and showing the different approaches to studying.

     

Delineating of groundwater potential zones based on remote sensing,GIS and analytical hierarchical process: a case of Waddai,eastern Chad

GeoJournal - The delineation of favourable areas of water potentials and their management must be based on rigorous scientific studies. Thus, geographic information system (GIS) and remote sensing...     

Flood hazard and risk analysis in the southwest region of Bangladesh

Flood hazard and risk assessment was conducted to identify the priority areas in the southwest region of Bangladesh for flood mitigation. Simulation of flood flow through the Gorai and Arial Khan river system and its floodplains was done by using a hydrodynamic model. After model calibration and verification, the model was used to simulate the flood flow of 100‐year return period for a duration of four months. The maximum flooding depths at different locations in the rivers and floodplains were determined. The process in determining long flooding durations at every grid point in the hydrodynamic model is laborious and time‐consuming. Therefore the flood durations were determined by using satellite images of the observed flood in 1988, which has a return period close to 100 years. Flood hazard assessment was done considering flooding depth and duration. By dividing the study area into smaller land units for hazard assessment, the hazard index and the hazard factor for each land unit for depth and duration of flooding were determined. From the hazard factors of the land units, a flood hazard map, which indicates the locations of different categories of hazard zones, was developed. It was found that 54% of the study area was in the medium hazard zone, 26% in the higher hazard zone and 20% in the lower hazard zone. Due to lack of sufficient flood damage data, flood damage vulnerability is simply considered proportional to population density. The flood risk factor of each land unit was determined as the product of the flood hazard factor and the vulnerability factor. Knowing the flood risk factors for the land units, a flood risk map was developed based on the risk factors. These maps are very useful for the inhabitants and floodplain management authorities to minimize flood damage and loss of human lives. Copyright © 2005 John Wiley & Sons, Ltd.     

Tectonic evolution of the basement complex in the central eastern desert of Egypt

The Egyptian basement rocks are gathered into three major rock groups, viz. Meatiq Group (oldest), Abu Ziran Group and Hammamat Group (youngest); the last two groups belong to the Pan-African orogenic cycle. The Meatiq Group is an old crystalline basement cropping out in gneiss domes. The Abu Ziran Group comprises the geosynclinal association which is formed of a lower ophiolite unit overlain by metasediments, volcanoclastics and locally intermediate volcanics having clear island arc characters. The Hammamat Group comprises molasse-type clastics, and penecontemporaneous Dokhan Volcanics of andesite to rhyolite composition; syn to late-tectonic calc-alkaline granites are the plutonic equivalents of the Dokhan Volcanics.The studied area lies within the foreland fold and thrust belt of a continental margin orogen. Ophiolites, particularly serpentinites, crop out along the trace of the sole thrust between the Meatiq infrastructure and the imbricated Abu Ziran nappe.Swells, developed along two geanticlines, were centers of marked calc-alkaline magmatic activity associated, at least, with gold mineralization.

---

Zusammenfassung Die Gesteine des ägyptischen Kristallins sind in drei Hauptgruppen unterteilt: Meatiq Group (älteste), Abu Ziran Group und Hammamat Group (jüngste); die letzten zwei Gruppen gehören dem Pan-Afrikanischen Zyklus an. Die Meatiq-Gruppe stellt einen alten Sokkel dar, der in Gneisdomen auftritt. Die Abu-Ziran-Gruppe umfaßt die Geosynklinal-Assoziation, die aus einer unteren ophiolitischen Einheit besteht, überlagert von Sedimenten, volkanoklastischen Sedimenten und lokalen intermediären Vulkaniten mit ausgeprägten Inselbogen-Eigenschaften. Die Hammamat-Gruppe besteht aus Molassetyp klastischen Sedimenten und zeitlich assoziierte Dokhan Volcanics andesitischer bis rhyolitischer Zusammensetzung. Die synbis spät-tektonische Kalkalkaligranite sind die plutonischen Aequivalente der Dokhan Volcanics.Das untersuchte Gebiet liegt im Vorland-Falten- und Decken-Gürtel eines Kontinentalrand-Orogens. Ophiolite, insbesondere die Serpentinite, treten entlang dem Ausbiß der Überschiebungsfläche zwischen dem Meatiq-Sockelstockwerk und der Abu-Ziran-Decke auf.Schwellen in Form zweier Geantiklinalen waren Zentren aktiver kalkalkaliner magmatischer Tätigkeit, begleitet zumindest von Goldvererzungen.

---

Résumé Les roches du socle égyptien se répartissent en trois groupes majeurs: Meatiq Group (le plus ancien); Abu Ziran Group et Hammamat Group (le plus récent); les deux derniers groupes appartiennent au cycle orogénique Pan-Africain.Le Meatiq Group est un socle cristallin ancien affleurant en dômes gneissiques. Le Abu Ziran Group comprend une association géosynclinale formée d'une unité ophiolitique inférieure suivie par des métasédiments, des volcanoclastites et localement par des roches volcaniques intermédiaires à caractere d'arc insulaire. Le Hammamat Group comprend des roches clastiques du type molassique, et des roches volcaniques pénécontemporaines de composition andésitique à rhyolitique (Dokhan Volcanics); des granites calco-alcalins syntectoniques à tardi-tectoniques sont les équivalents plutoniques des «Dokhan Volcanics».Le terrain étudié se situe dans l'avant-pays plissé et charrié d'un orogène de marge continentale. Des ophiolites, particulièrement des serpentinites, affleurent le long de la surface de charriage entre le massif autochtone de Meatiq et la nappe complexe d'Abu Ziran.Des dômes, développés le long de deux géanticlinaux, ont été les centres d'une forte activité magmatique calco-alcaline associée, au moins, à une minéralisation aurifère.

---

: Meatiq Group ( ), Abu Ziran Group Hammamat Group ( ); - . , . , , , , , , . , Dokhan . Dokhan - - . . , , Meatiq Abu-Ziran.

     

Identification of palaeochannels around Cauvery river near Talakad, Karnataka using remote sensing data

Visual interpretation of satellite images could help in the identification of present and past landforms. An attempt has been made to identify the palaeochannels of the Cauvery river in Karnataka state through visual interpretation of IRS-1C, LISS III False Colour Composites (FCC). In order to assess their inter-relationship with other hydrogeomorphic elements, various geomorphic units have been mapped. Major geomorphic units like alluvial plain, pediplain, valley fill. residual hill, ridges, meander scar, channel bars and water bodies have been demarcated. Considering the hydrogeomorphic setup of the palaeochannels. it is inferred that the disposition of palaeochannels of the area are controlled by the geology and structure and the prevailing geomorphic process.     

Changes to the Surface Level Solar Ultraviolet-B Radiation Due to Haze Perturbation

The South-East Asian region experienced a haze episode in 1994 which was widely believed to be due to widespread forest fires in Sumatra and Kalimantan (Indonesia). Broadband measurements of the surface level solar ultraviolet-B, UV-A and Global radiation at Penang (Malaysia) are used to study the effect of the 1994 haze on effective UV-B irradiance. We find that during the haze episode, there is enhanced absorption of surface level UV-B radiation. The effect of haze on UV-A and Global radiation is much less. The reduction in absolute noon time UV-B irradiance (mostly cloud free) during the 1994 haze period was 23% relative to the UV-B irradiance during thecorresponding haze-free period in 1995. Even though the noon time radiation data minimizes the cloud effect in the results presented some cloud effect is still present.     

Electron depletion in the wake of ionospheric spacecraft—A comparison between results from Langmuir probes and antennas

In situ observations of the electron depletion in the wakes of satellites and rockets in the ionosphere using Langmuir type probes and antennas are analyzed and compared. The quantitative degree of agreement between the results is demonstrated and discussed. One consequence is an improved interpretation of results previously presented for the OGO II Satellite wake.