Geology and Active Tectonics of the Lalmai Hills,Bangladesh–An Overview from Chittagong Tripura Fold Belt Perspective

The Lalmai Hills is a low amplitude anticline with significant variations in landforms, situated along the western fringe of the Chittagong-Tripura Fold Belt (CTFB) and immediate east of the Indo-Burmese deformation front. This fold belt of the Bengal Basin along with more easterly Indo-Burman Range (IBR) developed as a consequence of the oblique collision between Indian and Burmese plates. This neotectonic activity is still continuing and shaping the geomorphology of the area. This study is conducted based on the geomorphological observation of the topo maps and satellite images, and through reconnaissance field work. Stream length gradient index (SL Index) and Mountain front sinuosity (S_mf) reveals the relative status of tectonic activity. Anomalous SL index values confirm the position of the sympathetic minor faults and also relate to the local stratigraphy. A 2D structural model based on the seismic section reveals thrusts controlled wedge-shape upliftment of the central part as pop-up anticlinal structure. The western thrust is the direct result of the collision of the Indian and Burmese plates, and the eastern one is the back thrust of the western fault. Low S_mf value found in the western flank signifies recent tectonics and relatively high S_mf value in the eastern flank indicates that weathering intensity is relatively greater compared to western flank. Finally, the findings not only enhanced the understanding of geomorphic evolution and active tectonics of the Lalmai Hills area but also the overall tectonic and geomorphic evolution of the western most folded part of the CTFB.     

Analysis of dry and wet climate characteristics at Uttarakhand (India) using effective drought index

Natural Hazards - Drought is a complex natural disaster that adversely affects human life and the ecosystem. A variety of drought indexes are available for monitoring meteorological drought events....     

Application of Artificial Intelligence to Estimate Oil Flow Rate in Gas-Lift Wells

Natural Resources Research - Optimization and monitoring schemes for oil well and reservoir system require accurate estimation of production rate. Real-time monitoring is conducted typically using...     

Socio-political and ecological stresses on traditional pastoral systems: A review

Journal of Geographical Sciences - Pastoralism is a viable socio-economic system-shaped by landless and agro-pastoral communities in many pastoral regions of the world. This system is mainly based...     

Physical and geometrical parameters of VCBS XIII: HIP 105947

The best physical and geometrical parameters of the main sequence close visual binary system(CVBS), HIP 105947, are presented. These parameters have been constructed conclusively using Al-Wardat's complex method for analyzing CVBSs, which is a method for constructing a synthetic spectral energy distribution(SED) for the entire binary system using individual SEDs for each component star. The model atmospheres are in its turn built using the Kurucz(ATLAS9) line-blanketed plane-parallel models. At the same time, the orbital parameters for the system are calculated using Tokovinin's dynamical method for constructing the best orbits of an interferometric binary system. Moreover, the mass-sum of the components, as well as the ?θ and ?ρ residuals for the system, is introduced. The combination of Al-Wardat's and Tokovinin's methods yields the best estimations of the physical and geometrical parameters. The positions of the components in the system on the evolutionary tracks and isochrones are plotted and the formation and evolution of the system are discussed.     

Nutrient and metal accumulation in a freshwater tidal marsh

Stratigraphic records from sediment cores collected in a freshwater tidal marsh and in the estuary upstream and downstream from the marsh were used to determine the accumulation of nutrients and trace metals over long time periods. Analysis of pollen and seeds show that the high marsh has formed only within the past 100 yr, following increased sedimentation rates in the area. Variations in nutrient and trace metal accumulations over several decades show that pollutants from agricultural runoff and wastewater discharge are stored to a greater extent in high-marsh than in low-marsh sediments. Greater accumulation rates in the high marsh are probably related to its greater sedimentary organic carbon concentration.     

Effects of search parameters on kriged reserve estimates

Summary Reliable ore reserve estimates for deposits with highly skewed grade distributions are difficult tasks to perform. Although some recent geostatistical techniques are available to handle problems with these estimations, ordinary kriging or conventional interpolation methods are still widely used to estimate the ore reserves for such deposits. The estimation results can be very sensitive to the search parameters used during the interpolation of grades with these methods.This paper compares the ore reserve estimates from ordinary kriging using several cases in which certain search parameters are varied. The comparisons are extended to different mineralizations to show the changing effects of these parameters.     

Protected areas in Saudi Arabia: Sustainable use of natural resources

The present paper reviews the conservation movement in Saudi Arabia as measured against the established protected areas, as well as the basic philosophy regarding natural resource management. The degree of representation of the biophysical diversity of Saudi Arabia in the established protected areas is discussed by using three areas as case studies: Harrat Al-Harrah (lava field), Urug Bani Mu'arid (Cuesta and Sand), and Raydah Escarpment (High Mountain).     

Species Composition and Some Ecological Notes on Diatom Communities of a Lotic Environment in Tarhunãh,Libya Artenzusammensetzung und einige ökologische Notizen über Diatomeengesellschaften eines lotischen Biotops in Tarhunãh/Libyen

Libya occupies a large part of the Sahara Desert, and is a predominantly arid country with extremely scarce freshwaters. Despite aridity, a distinct higher rainfall zone exists along its mediterranean coastal belt. A lotic environment (perennial stream) in Ain-Scersciara, Tarhunãh in northwest Libya was studied for the species composition of diatom communities and their ecological characteristics. The waters are generally alkaline (pH = 7.5) and of hard-water (conductivity = 2008 μS/cm) type. The epiphytic diatom growth on benthic filamentous algae was high (32 taxa) with Amphora veneta as a very common taxon. Gomphonema parvulum var. micropus was an important taxon found in scrapings from the leaves of macrophytes and stony substratum. Nitzschia and Navicula showed high species richness (9 taxa in each) followed by Gomphonema (6 taxa). The ecological attributes of the majority of taxa show an oligohalobe status and alkaliphilous indicator.     

Studies on Limnobiotic Conditions in a Thermal Spring at Tajura, (Tripoli), Libya

Summary: Studies on a hot spring at Tajura (Libya) indicated narrow fluctuations in water temperature (43 … 44.5 °C) near the source site. A wide thermal gradient of 10 K between two sampling sites (near the source and in the marsh) recorded in December narrowed to 3 … 4.5 K in March. Similar pH values (6.7) near the source increased along the runoff channel and touched 6.9 in the marsh. Bicarbonate alkalinity always exceeded 400 mg/l; likewise conductivity was remarkably high (>4700 μS/cm). Scarce algal growth was observed near the source site, though mats of variable thickness prevailed along the runoff channel and in the marsh.