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21.
Mohamed El Mourabet Ahmed Barakat Mohamed Najib Zaghloul Mohamed El Baghdadi 《Arabian Journal of Geosciences》2018,11(6):126
This study focuses on the Lower-Middle Miocene syn-orogenic flysch deposits of the Zoumi basin to infer source area paleoclimatic conditions, the intensity of source rocks paleoweathering, and mechanical sorting and recycling effects. The mudrocks are enriched in Al2O3, Fe2O3, CaO, and TiO2 relative to PAAS and depleted in the other mobile major elements. There are high positive correlations between SiO2, Al2O3, and TiO2 and negative correlations between SiO2 and CaO. Geochemically, the mudstones are mainly classified as shales, Fe-shales, and wackes. Various discriminant diagrams were used to reveal the inferred tectonics, source paleoweathering intensity, and paleoclimatic conditions. Chemical index of alteration (CIA) and chemical index of weathering (CIW) values for Lower-Middle Miocene vary from 50 to 80% indicating low to moderate degree of source area weathering compatible with non-steady-state weathering under wet and humid paleoclimatic conditions. Locally (Zoumi mid-section) CIA values are higher (>?80) reflecting intense source area weathering, which may be attributed to high tectonic impulses and more humid conditions during deposition. The combination of ICV-CIA, Al2O3-Zr-TiO2, and Th/Sc-Zr/Sc values suggests the bulk rock is chemically immature and has experienced modest physical sorting and recycling reflecting little transportation until the final deposition. 相似文献
22.
On computation of conditional mean spectrum in Eastern Canada 总被引：2，自引：2，他引：0
23.
Nazarin Ezzaty Mohd Najib Kasturi Devi Kanniah 《Singapore journal of tropical geography》2019,40(2):272-290
This study aims to map forest cover in Peninsular Malaysia using satellite images as deforestation is of concern in the recent decades, and is an important environmental issue for the future too. The Carnegie Landsat Analysis System‐Lite (CLASlite) program was used in this study to detect forest cover in Peninsular Malaysia using Landsat satellite data. The results of the study show that CLASlite algorithm misclassified some oil palm, rubber and urban areas as forest vegetation. A reliable forest cover map was produced by first combining Landsat and ALOS PALSAR images to identify oil palm, rubber and urban areas, and then subsequently removing them. The HH and HV polarization data of ALOS PALSAR (threshold method) could detect oil palm plantations with 85.26 per cent of overall accuracy. For urban area detection, Enhance Build up Index (EBBI) using spectral bands from Landsat provided higher overall accuracy of 94 per cent. These methods produced a forest cover reading of 5 914 421 ha with an overall classification accuracy of 94.5 per cent. The forest cover (including rubber areas) detected in this study is 0.38 per cent higher than the percentage of 2010 forest cover detected by the Forestry Department of Peninsular Malaysia. The technique described in this paper presents an alternative and viable approach for updating forest cover maps in Malaysia. 相似文献
24.
Mohamed El Mourabet Ahmed Barakat Jamila Rais Mohamed Najib Zaghloul Achraf Atouabat 《Arabian Journal of Geosciences》2018,11(9):209
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). 相似文献
25.
Khadija Aboumaria Mohamed Najib Zaghloul Maria Battaglia Francesco Loiacono Diego Puglisi M&#x;hamed Aberkan 《Journal of African Earth Sciences》2009,55(1-2):10
This work deals with new lithostratigraphic, sedimentological, petrographic and geochemical data collected from coastal Quaternary formations of the Tangier Peninsula along the Northern Atlantic and Mediterranean coasts in the southern side of the Gibraltar Strait (Morocco).The sedimentological features of the analyzed sections reflect a palaeoenvironment evolution from a submerged beach-type to a high energy littoral depositional system, namely lower shoreface to beachface environment with a regressive trend to thickening- and coarsening-upward sequences. Other successions, located nearby Larache city and in the Sidi Kankouch area, are also characterized by a positive trend to fining- and thinning-upward sequences, reflecting an evolution from lower beachface or upper shoreface to lower shoreface. It is possible that the transgressive to regressive trend inversion could be related to fluctuations of sediment input rate versus accommodation space during the progradation of a coastal palaeoenvironment.The lateral and vertical evolution of the studied marine formations is related to late Quaternary neotectonics, mainly to the last repercussions of isostatic rebound of the External and Flysch Basin Domains, during a period of relatively uniform sea level between 280,000 and 125,000 years B.P.The provenance of arenites of these Quaternary marine formations, studied by means of modal counting and geochemical analysis, seems to be linked mainly to Middle-Upper Miocene and Pliocene terrigenous successions, unconformably resting on various formations of the Neogene accretionary prism. The latter has been built by the stacking of Flysch Nappes and External Units of the Northern Rif Chain. 相似文献
26.
This work deals with the tectonic interpretation of an alignment of more than 300 sinkholes stretching along the Jordanian coast of the Dead Sea, Ghor Al Haditha area. Its dimensions are 6 km long with a width of 600 m. Sinkholes appeared during the last decades as a consequence of the very rapid lowering of the lake level. The linear shape was inferred from ground collapse inventories carried out between 1991 and 2008. The lineament is replaced and analyzed in its structural setting at regional and local scales. Its direction (N 24° E) is sub‐parallel to the ones displayed by many focal mechanisms, especially the one associated with the earthquake of the 23 April, 1979 (mb = 5·1; N 20° E ± 5°), which is representative of all focal mechanisms calculated on a fault plane compatible with the general direction of the Jordan‐Dead Sea Transform fault system for the east coast of the Dead Sea area. The alignment of sinkholes is constituted by 13 minor linear segments separated by as many empty spaces. Four minor linear units present an en‐echelon arrangement from which one can deduce the presence of a local extensional stress field. In this context, the sinkhole locations provide information of subsurface discontinuities interpreted as hidden fractures. In a close future, such results could support the work of decision‐makers and engineers in the projected development of the area. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
27.
This paper investigates damping modification factors in eastern Canada based on historical and simulated records compatible with seismic hazard in this region. Damping modification factors are characterized as a function of magnitude, distance, site condition, and damping ratio. Damping modification factors corresponding to historical and simulated ground motions on rock sites are shown to exhibit the same trends for all damping levels. In addition to period dependency of damping modification factors, we demonstrate their sensitivity to magnitude variations at longer periods. The effect of distance is shown to be less pronounced. It is also observed that soil conditions affect damping modification factors at short as well as longer periods. Period-dependent equations are proposed for practical assessment of damping modification factors corresponding to damping ratios between 1 and 40%, considering different magnitude–distance combinations and soil conditions representative of seismic hazard in eastern Canada. 相似文献