Snow and stream-water chemistry of the Ganga headwater basin,Garhwal Himalaya,India

Abstract

Studies of the chemical composition of snowpack and stream water were carried out in a catchment having an area of 53km² (31°03′-30°55′N and 78°40′-78°51′E) in the Garhwal Himalaya, India. The dominant ions in the snowpack and stream water were Ca²⁺, Na⁺, NO^? ₃, SO^2- ₄ and HCO^? ₃. Solute patterns in the snowpack show preferential elution. Investigation of the chemical composition of stream water shows that meltwater changes its composition substantially as it passes through soil pathways to the stream. The groundwater flushing perhaps controls the chemical composition of meltwater in the early spring. However, in the period from July to September, the stream water carries the chemical signature of monsoonal precipitation.     

Statefinder parameter for varying G in three fluid system

In this work, we have considered variable G in flat FRW universe filled with the mixture of dark energy, dark matter and radiation. If there is no interaction between the three fluids, the deceleration parameter and statefinder parameters have been calculated in terms of dimensionless density parameters which can be fixed by observational data. Also the interaction between three fluids has been analyzed due to constant G. The statefinder parameters also calculated in two cases: pressure is constant and pressure is variable.     

Application of GIS for the identification and demarcation of selective heavy metal concentrations in the urban groundwater

Groundwater is the most appropriate and widely used source of drinking water, which is increasingly threatened by pollution from industrial and agricultural activities. To check the severity of the problem, 156 groundwater samples were collected from various depths (60-110 ft) of 52 different localities in Faisalabad city, the third largest metropolis in Pakistan, and analyzed for the metals (Zn, Cu, Cd, Ni, Pb, Mn and Fe) concentration in 2009. Quantification was done by using Flame Atomic Absorption Spectrophotometer technique and the results were compared with WHO standards for drinking water quality. Results showed that the levels of Cu, Mn and Fe were below the WHO standards while the concentrations of Zn, Cd, Ni and Pb were above the recommended levels of safe drinking water. Correlation analysis among the occurrence of these heavy metals revealed a highly significant and positive correlation of Mn with Zn and Fe. A significant and positive correlation of Cd was also found with Cu and groundwater depth showing that there is strong association between Cu-Cd pair and that the Cd concentration varies with depth of groundwater in the study area. Regional patterns of heavy metals occurrence were mapped using Geographical Information System (GIS) for the identification and demarcation of risk areas. The concentration maps may be used by policymakers of the city to mitigate groundwater pollution.     

The Interrelationship of Micro-Meso and Macroscopic Structures on the Western Limb of the Hazara Kashmir Syntaxis, Pakistan

Detailed micro-meso to macroscopic structural analyses reveal two deformation phases in the western limb of the Hazara-Kashmir Syntaxis(HKS). Bulk top to NW shearing transformed initially symmetrical NNE-SSW trending meso to macroscopic folds from asymmetric to overturned ones without changing their trend. Sigmoidal en-echelon tension gashes developed during this deformation,that were oblique to bedding parallel worm burrows and bedding planes themselves. Strain analyses of deformed elliptical ooids using the R_f/φ method constrain the internal strain patterns of the NNE-SSW structures. The principal stretching axis(S_3) defined by deformed elliptical ooids is oriented N27°E at right angles to WNW-ESE shortening. The deformed elliptical ooids in sub-vertical bedding vertical planes contain ooids that plunge ~70° SE due to NW-directed tectonic transport. Finite strain ratios are1.45(R_(xy)) parallel to bedding plane and 1.46(R_(yz)) for the vertical plane. From these 2D strain values, we derive an oblate strain ellipsoidal in 3D using the Flinn and Hsu/Nadai techniques. Strains calculated from deformed elliptical ooids average-18.10% parallel to bedding and-18.47% in the vertical plane.However, a balanced cross-section through the study area indicates a minimum of~-28% shortening.Consequently, regional shortening was only partially accommodated by internal deformation.     

Tectonic setting and sedimentology of Ganga River sediments, India

The Ganga basin provides a present-day example of a peripheral foreland basin. The course of the river is controlled by Himalayan tectonics. Three main types of architectural elements, such as channels (CH), sandy bedforms (SB) and overbank fines (OF) have been developed in Ganga River sediments. The channels (CH) include gravelly (Gs) and sandy channel (Ss) lithofacies. The sandy bedforms (SB) include trough cross-stratified (St), planar cross-stratified (Sp), horizontal stratified (Sh), sandy massive (Sm) and climbing ripple cross-laminated (Sr) lithofacies, all of which are active channel deposits. The overbank fines (OF) include massive silt and clay (Fm), parallel laminated silt and clay (FI) and climbing ripple cross-laminated (Sr) lithofacies. Mega units have been developed in the lower part of the active channel deposits, while small units have been developed in the upper part of active channel deposits, in inactive channel deposits and overbank fines. This study illustrates the seasonal and tectonic control on sedimentation. Petrofacies studies of the sediments indicate a recycled orogen provenance. The sediments are derived from rapidly uplifted fault blocks comprising granite, gneiss and basic and ultrabasic rocks. Lack of textural and compositional maturity suggests a local source of derivation. The principal control on sand composition is source lithology. The hot and humid climate may slightly increase the content of quartz in sand derived from reworked foreland basin sediments. but the effect is neither sufficient to shift the sand compositions out of the recycled orogen field nor does it obscure composition mixing patterns.     

Evaluating thermal history models for the Otway Basin, southeastern Australia, using (U-Th)/He and fission-track data from borehole apatites

New apatite helium and fission-track data from the Otway Basin are consistent with previously published borehole ages, confirming earlier suggestions that existing thermal models for basin evolution should be reevaluated. Analysis of the relationship between helium ages and grain size in newly analyzed samples, as well as in samples previously reported, reveals that grain size variations may contribute to the previously reported scatter in helium ages among aliquots of the same sample. In addition, systematic variations in apatite grain size with borehole depth or temperature may also have a significant effect on the interpretation of borehole helium age data. Incorporation of the observed grain size variations in Otway borehole apatites into forward models based on published thermal histories, principally based on vitrinite reflectance and fission-track data, suggests that existing models for the eastern Otway Basin are broadly consistent with the helium data. In contrast, thermal histories for western basin boreholes, now thought to be at maximum temperatures, predict helium ages that are generally older than the observed ages, implying that basin temperatures were hotter than indicated by the models. This discrepancy is consistent with a Cenozoic heating event in parts of the western Otway Basin similar to that documented for the eastern basin. The relatively wide spread of apparent apatite fission-track (AFT) ages and compositions compared to the restricted age range of helium measurements on coexisting grains, although not conclusive, supports previous suggestions that composition does not appear to affect the sensitivity of the He closure temperature in apatite.     

Plate-plume-accretion tectonics in Proterozoic terrain of northeastern Rajasthan, India: Evidence from mafic volcanic rocks of north Delhi fold belt

Abstract   The northern part of the Aravalli mountain belt of northwestern Indian shield is broadly composed of three Proterozoic volcano-sedimentary domains, i.e. the Bayana, the Alwar and the Khetri basins, comprising collectively the north Delhi fold belt. Major, trace and rare earth element concentrations of mafic volcanic rocks of the three basins exhibit considerable diversity. Bayana and Alwar volcanics are typical tholeiites showing close similarity with low Ti–continental flood basalts (CFB) with the difference that the former shows enriched and the latter flat incompatible trace element and rare earth element (REE) patterns. However, the Khetri volcanics exhibit a transitional composition between tholeiite and calc-alkaline basalts. It appears that the melts of Bayana and Alwar tholeiites were generated by partial melting of a common source within the spinel stability field possibly in the presence of mantle plume. During ascent to the surface the Bayana tholeiites suffered crustal contamination but the Alwar tholeiites erupted unaffected. Geochemically, the Khetri volcanics are arc-like basalts which were generated in a segment of mantle overlying a Proterozoic subduction zone. It is suggested that at about 1800 Ma the continental lithosphere in northeastern Rajasthan stretched, attenuated and fractured in response to a rising plume. The produced rifts have undergone variable degrees of crustal extension. The extension and attenuation of the crust facilitated shallowing of the asthenosphere which suffered variable degree of melting to produce tholeiitic melts – different batches of which underwent different degrees of lithospheric contamination depending upon the thickness of the crust in different rifted basins. The occurrence of subduction-related basaltic rocks of Khetri Belt suggests that a basin on the western margin of the craton developed into a mature oceanic basin.     

Biostratigraphy,Depositional and Diagenetic Processes in Carbonate Rocks from Southern Lebanon: Impact on Porosity and Permeability

Carbonate rocks contain prolific hydrocarbon reserves all over the world, particularly in the Middle East. For exploration and production strategies, it is essential to understand carbonate reservoirs in terms of their internal characteristics, depositional environment, relative age, diagenetic processes and impact on petrophysical properties. This study has been performed on exposed Cretaceous, Paleocene and Miocene marine carbonate sedimentary sequences in two localities (Maghdoucheh and Qennarit) near the city of Sidon (Southern Lebanon). It represents the first comprehensive study that takes into consideration the carbonate reservoir facies, diagenetic history and reservoir quality in the area. Rocks at Maghdoucheh are mainly dominated by limestone beds showing sedimentary structures and erosive bases alternating with microfossil-rich silty marls, related to a shallowing upward sequence in a restricted marine platform environment. Shells of benthic foraminifera and mollusks dominate the fossil assemblage extracted from the studied rocks. The microfossil and nannofossil assemblage detected in the Maghdoucheh sections indicates a middle Miocene age. Rocks at Qennarit are composed of mudstone/wackestone limestone beds rich in planktonic foraminifera and nannofossils related to open marine conditions. Based on the nannofossil content, rocks from Qennarit 1 and 2 are Paleocene and Cretaceous in age, respectively. Four main types of microfacies have been identified, i.e. (1) microbioclastic peloidal calcisiltite, (2) pelagic lime mudstone and wackestone with planktonic microfossils, (3) grainstone/packstone with abundant foraminifera and (4) fenestral bindstones, mudstones and packstones with porostromate microstructures. The porosity-permeability (poro-perm) analysis of representative samples reveals moderate to good porosity but very low permeability. This is mainly due to the presence of large moldic pores that are isolated in nature. The diagenetic features are dominated by micritization and dissolution (both fabric selective and non-fabric selective). Among all diagenetic features, dissolution in both localities contributes to porosity enhancement, while micritization, cementation, compaction and the filled fractures have negative impacts on permeability; hence the overall reservoir quality.     

Participatory action research: working beyond disaster toward prevention

Drawing on qualitative analyses of post-disaster effects on vulnerable rural communities in Pakistan, this paper puts forward a participatory action research stance as a next step or approach toward prevention. This approach stands in contrast to the current post-disaster relief model commonly practiced by many non-government organizations (NGOs). The participatory action research perspective was used to examine the qualitative evidence and provide a framework to effectively work with rural vulnerable communities. Qualitative analyses documented community wisdom and ideas toward prevention which, when potentially partnered with resources offered by NGOs, could dramatically reduce their vulnerability to natural disasters.