Cretaceous paleomargin tilted blocks geometry in northern Tunisia: stratigraphic consideration and fault kinematic analysis

New stratigraphic data, lithostratigraphic correlations, and fault kinematic analysis are used to discuss the basin geometry and sedimentation patterns of the northeastern Tunisia during Cretaceous times. Significant facies and thickness variations are deduced along the northeastern Atlas of Tunisia. The NW-SE 80-km-long regional correlation suggests a high sedimentation rate associated with irregular sea floor. The fault kinematic analysis highlights N-S to NE-SW tectonic extension during Early Cretaceous. During Aptian–Albian times, an extensional regime is recognized with NE-SW tectonic extension. The Cenomanian–Turonian fault populations highlight a WNW-ESE to NW-SE extension, and Campanian–Maastrichtian faults illustrate an NW-SE extension. The normal faulting is associated to repetitive local depocenters with a high rate of sedimentation as well as abundant syntectonic conglomeratic horizons, slump folds, and halokinetic structures. The sequence correlation shows repetitive local depocenters characterizing the basin during Early Cretaceous times. All the above arguments are in favor of basin configuration with tilted blocks geometry. This geometry is shaped by major synsedimentary intra-basin listric normal faults, themselves related to the extensional setting of the southern Tethyan paleomargin, which persisted into the Campanian–Maastrichtian times. The results support a predominant relationship between tilted blocks geometry and sedimentation rather than E-W “Tunisian trough” as it was previously accepted.     

Petrology of lower-middle Miocene Zoumi Flysch Fm. (Mesorif sub-domain,Rif belt,Morocco): first evidence of mixed mode provenance and geodynamic setting

The Zoumi Basin was generated in a collisional tectonic setting during the Lower-Middle Miocene. The syn-orogenic flysch deposits of the basin have been well investigated by petrographic and geochemical studies to characterize the composition, source to sink routing system, and tectonic setting of the Zoumi flysch. Forty-three sandstone samples and 45 mudstone samples have been gathered from six measured stratigraphic sections. These samples have been analyzed using XRD, XRF, inductively coupled plasma-mass spectrometry (ICP-MS) for mudrocks and petrographic investigation for sandstones. The Lower-Middle Miocene Zoumi flysch is defined as sublitharenites and quartzarenites according to mineralogical content. Detrital grains are commonly subangular to subrounded, poorly sorted, and rich in quartz grains. Point counting modal analysis leads to craton interior and recycled orogen provenance with significant first-cycle sediment supply and low sedimentary recycling. Several chemical ratios (Al₂O₃/TiO₂, La/Th, Cr/Th, Th/Sc, Zr/Sc) as well as chondrite-normalized REE patterns with flat HREE, LREE enrichment, and negative Eu anomaly suggest a dominant felsic rock sources. However, V-Ni-La*4, V-Ni-Th*10, and Th/Sc vs. Cr/Th plots do not exclude a mafic supply source nature which is evidenced by numerous ophiolitic outcrops scattered throughout the Mesorifan Subdomain (Mesorifan Ophiolitic Suture Zone).     

Perogenesis of granites, Sharm El-Sheikh area, South Sinai, Egypt: petrological constrains and tectonic evolution

Precambrian granites of the Sharm El-Sheikh area in south Sinai, Egypt belong to collisional and post-collisional Magmatism (610–580 Ma). The granites are widely distributed in the northern part of the Neoproterozoic Arabian-Nubian Shield. South Sinai includes important components of successive multiple stages of upper crust granitic rocks. The earliest stages include monzogranite and syenogranites while the later stages produced alkali feldspar granites and riebeckite-bearing granites. Numerous felsic, mafic dikes and quartz veins traverse the study granites. Petrographically, the granitic rocks consist mainly of perthite, plagioclase, quartz, biotite and riebeckite. Analysis results portray monzogranites displaying calc-alkaline characteristics and emplaced in island-arc tectonic settings, whereas the syenogranites, alkali-feldspar granites and the riebeckite bearing-granites exhibit an alkaline nature and are enriched in HFSEs similar to granites within an extensional regime. Multi-element variation diagrams and geochemical characteristics reinforce a post-collision tectonic setting. REEs geochemical modeling reveals that the rocks were generated as a result of partial melting and fractionation of lower crust basaltic magma giving rise to A₁ and A₂ subtype granites. They were subsequently emplaced within an intraplate environment at the end of the Pan-African Orogeny.     

Assessment of land degradation east of the Nile Delta, Egypt using remote sensing and GIS techniques

Land degradation is one of the most common issues in the eastern part of the Nile Delta area that threatens the ongoing agricultural activities and prohibits further reclamation expansions. The different degradation types and the associated risk assessment of some soils types of western Suez Canal region during the period from 1997 to 2010 is discussed. The assessment of the different degradation degrees in the investigated area has been carried out through integrating remote sensing, GIS and GLASOD approaches. Results revealed that the salinization, alkalization, soil compaction and water logging are the main types of land degradation in the area. The main causative factors of human induced land degradation types are; over irrigation, human intervention in natural drainage, improper time use of heavy machinery and the absence of conservation measurements. Low and moderately clay flats, gypsifferous flats, have high to very high risk in both salinization sodication and physical degradation. Values such as EC, ESP, and ground water level reach 104.0 dS/m, 176? % and 60 cm, respectively. These results will be of great help and be basic sources for the planners and decision makers in sustainable planning. The spatial land degradation model was developed based on integration between remote sensing data, geographic information system, soil characteristics and DEM.     

Transportation characteristics change under rapid urban expansion: A case study of Shanghai

This paper focuses on the economic development and urban morphology as well as its impact on the transportation system during the urban expansion of Shanghai in the last more than 20 years(1986-2008).Based on data from 3 comprehensive transport surveys of Shanghai since 1986,the changes in residential trip demand,vehicle use,and the spatial distribution of trips were studied to understand the demands on the transportation system.The factors contributing to those changes in transportation demand were discuss...     

Expansion theory for the elliptic motion of arbitrary eccentricity and semi-major axis

In this paper of the series, literal analytical expressions for the coefficients of the Fourier series representation ofG will be established for anyx _i; withn, N positive integers and |_i|<1 fori=1, 2, ... n. Moreover, the recurrence formulae satisfied by these coefficients will also be established. Illustrative analytical examples and a full recursive computational algorithm, with its numerical results, are included. The applications of the recurrence formulae are also illustrated by their stencils. As by-products of the analyses are two important periodic integrals developed analytically and computationally.     

Copepod community structure during upwelling and non-upwelling seasons in coastal waters off Cochin, southwest coast of India

Vypeen, an island of Cochin estuarine system, acts as the spawning site of several marine and estuarine fishes. We assumed that, physical process(upwelling) make changes in hydrography and the production of chlorophyll a in coastal waters off Vypeen. These alterations can influence the zooplankton abundance and copepod community structure in that area. For justifying this hypothesis, samples were collected from Vypeen at 10 m and 30 m locations during January(pre-southwest monsoon), August(late-southwest monsoon) and November(postsouthwest monsoon) 2014. During August, subsurface water column was cool, nutrient rich and less oxygenated(signatures of upwelling) than in November and January. Maximum concentrations of nitrate and chlorophyll a were recorded during August. In the present study, 15 zooplankton groups were recorded; of which copepods were the most predominant group(73%–90%). Copepod density in the present study ranged between 527.2 ind./m~3 and 5 139.2 ind./m~3. Totally, 37 copepods species were reported in present study and copepod species richness was higher during January. The abundance of zooplankton and copepods was high in August during late-southwest monsoon. These variations were closely associated with the coastal upwelling in August and weakening of moderate upwelling in November. In SIMPER analysis, it was found that the copepods species distribution was similar within season and dissimilar between the three seasons. Moreover, the higher abundance of upwelling indicator species Temora turbinata was recorded in August, which confirms the signs of seasonal upwelling in Vypeen. The present study emphasized on the influence of hydrographical parameters associated with physical process, in governing the copepod community organization of the Vypeen Island.     

Pan-African (intraplate and subduction-related?) metasomatism in the Fawakhir ophiolitic serpentinites, Central Eastern Desert of Egypt: mineralogical and geochemical evidences

Fawakhir serpentinites are the most western ophiolitic ultramafics relative to the Pan-African collision suture at the Qift-Quseir road in the Central Eastern Desert of Egypt. Their location is the basis for their selection in examining the possible contribution of the westerly dipping subducted oceanic slab-related melt/fluid with the intraplate granitic intrusion-related melt/fluid in the metasomatism of the Neoproterozoic ophiolitic serpentinites in the Eastern Desert. Non-residual mineralogy and geochemistry of serpentinites (SF1) far from the post-collision A2-type Fawakhir granitoids and those of serpentinites (SF2) in the vicinity of the granitoid pluton were investigated. The Fawakhir serpentinites are harzburgitic in composition and the Cr# (0.66–0.80) and Mg# (0.32–0.50) of their unaltered spinel cores are indicators for their forearc setting, where they were formed in the oceanic mantle wedge. Based on the spinel Cr# and the whole rock Yb–V bivariate, the melt extraction from the primitive mantle is in excess of 18% up to 24%. The HREE pattern of the SF1 serpentinites refers to the fractional type of melting. The formation of non-residual mineral phases particularly in SF2 samples (amphibole, biotite, apatite thorite, and monazite) and the enrichment of all serpentinites in trace incompatible elements refer to these two serpentinite groups having underwent modal metasomatism. It is suggested that viscous fluid/melt related to the Fawakhir granitoid emplacement metasomatized the SF2 serpentinites, causing a strong enrichment in LREE (display concave LREE; La_N/Sm_N?=?3.32–6.25 and U-type HREE; Gd_N/Yb_N?=?1.14–2.69) and a slight enrichment in Zr (12–16.62 ppm). All serpentinites are enriched in fluid-mobile elements by aqueous fluids, but the SF2 are more enriched in these elements. The spiked B compared to the other fluid-mobile elements (16.97–24.61 and 42.94–60.66?×?PM in SF1 and SF2 samples, respectively) suggests that these elements were added to the obducted ophiolitic Fawakhir serpentinites by the percolation of subduction-related fluids at shallow depths. The contribution of B from shallow continental crust-related fluids is debated. Hosting the Fawakhir serpentinites for the gold deposit at Fawakhir Mine implies a possible genetic relation between gold mineralizations hosted in the ultramafic rocks of the ANS and the processes of recycling of the subducted oceanic slab and the interaction with the mantle. Detailed stable and radiogenic isotopic analyses of the mineralization zones are required to address this question.