Effects of Trace Elements on Human Metabolism and Their Presence in the Potable Water of Ganga–Nim Groundwater Basin,India

The concentration of trace elements in the groundwater of the Ganga–Nim basin was ascertained. It was found that Zn, Cu, Cd, and Mn are below the permissible limits. Fe and Pb are above the permissible limits.     

Hf-Nd isotope evidence for contemporaneous subduction processes in the source of late Archean arc lavas from the Superior Province, Canada

Volcanic suites from Wawa greenstone belts in the southern Superior Province comprise an association of typical late Archean arc volcanic rocks including adakites, magnesian andesites (MA), niobium-enriched basalts (NEB), and ‘normal’ tholeiitic to calc-alkaline basalts to rhyolites. The adakites represent melts from subducted oceanic crust and all other suites were derived from the mantle wedge above the subducting oceanic lithosphere. The magnesian andesites are interpreted to be the product of hybridization of adakite melts with arc mantle wedge peridotite. The initial ?_Hf values of the ∼2.7 Ga Wawa adakites (+3.5 to +5.2), magnesian andesites (+2.6 to +5.1), niobium-enriched basalts (+4.4 to +6.6), and ‘normal’ tholeiitic to calc-alkaline arc basalts (+5.3 to +6.4) are consistent with long-term depleted mantle sources. The niobium-enriched basalts and ‘normal’ arc basalts have more depleted ?_Hf values than the adakites and magnesian andesites. The initial ?_Nd values in the magnesian andesites (+0.4 to +2.0), niobium-enriched basalts (+1.4 to +2.4), and ‘normal’ arc tholeiitic to calc-alkaline basalts (+1.6 to +2.9) overlap with, but extend to lower values than, the slab-derived adakites (+2.3 to +2.8). The lower initial ?_Nd values in the mantle-wedge-derived suites, particularly in the magnesian andesites, are attributed to recycling of an Nd-enriched component with lower ?_Nd to the mantle wedge. As a group, the slab-derived adakites plot closest to the 2.7 Ga depleted mantle value in ?_Nd versus ?_Hf space, additionally suggesting that the Nd-enriched component in the mantle wedge did not originate from the 2.7 Ga slab-derived melts. Accordingly, we suggest that the enriched component had been added to the mantle wedge at variable proportions by recycling of older continental material. This recycling process may have occurred as early as 50-70 Ma before the initiation of the 2.7 Ga subduction zone. The selective enrichment of Nd in the sources of the Superior Province magmas can be explained by experimental studies and geochemical observations in modern subduction systems, indicating that light rare earth elements (e.g., La, Ce, Sm, Nd) are more soluble than high field strength elements (e.g., Zr, Hf, Nb, Ta) in aqueous fluids that are derived from subducted slabs. As a corollary, we suggest that the recycled Nd-enriched component was added to the mantle source of the Wawa arc magmas by dehydration of subducted sediments.     

Environmental impact assessment using rapid impact assessment matrix (RIAM) for Russeifa landfill, Jordan

An environmental impact assessment (EIA) study for the solid waste landfill was prepared for the Russeifa area, northeast Jordan. As landfill was not subjected to sophisticated EIA, serious environmental problems are still occurring, such as groundwater contamination and air pollution. Three alternatives were proposed to rehabilitate the landfill: upgrading the existing landfill, construction of a biogas plant and its relocation. The EIA for the three options was carried out using the rapid impact assessment matrix (RIAM), it applies a consistent and recordable assessment of the importance of the different components. The scoping components included in the RIAM were: physical/chemical, biological/ecological, social/cultural and economic/operational components. The RIAM analysis showed that the least negative impacts would be to relocate to a better-managed sanitary landfill. The most serious negative impacts were the contamination of groundwater, air pollution and public health. These impacts can be mitigated through a comprehensive environmental management plan for the Russeifa landfill to address the deterioration of environmental components in the vicinity of landfill.     

Emeishan large igneous province, SW China

In recent years, there have been major advances in our understanding of the Emeishan large igneous province (LIP) of SW China following publication of a number of LIP-focused investigations of the terrain and associated rocks. This paper reviews the current state of knowledge. The volcanic and upper-intrusive portion of the province is relatively small (0.3×10⁶ km³), even when offset fragments, eroded sections and buried portions are included in the volume calculation. The most reliable radiometric age dates (zircon U–Pb SHRIMP from an associated layered intrusive body several kilometers in area) indicate generation at 259 Ma, consistent with the end-Guadalupian (end Middle Permian) stratigraphic age. In addition, several Ar–Ar dating studies have been carried out, mainly on the volcanic rocks, with a number of reported dates 253–251 Ma (Late Permian), but a consensus is emerging that these ages are problematic because they are in conflict with the stratigraphic data (possibly due to a monitor standard miscalibration). The Ar–Ar investigations have also yielded a large number of secondary ages, which are clustered at 175, 142, 98 and 42 Ma, and these are inferred to record sub-regional tectonic events that affected the western Yangtze Block as East Asia was assembled and later deformed by India’s collision–indentation into Asia. Magnetostratigraphic data and field observations suggest that the bulk of the volcanic sequence formed within 1–2 my. The geochemistry of the volcanic rocks and bio-lithostratigraphic studies of the underlying Maokou Formation suggests a mantle plume generated the province. The basalts can be classified into low and high Ti groups with different parental magmas. The low Ti basalts are confined to the western part of the province and are overlain by the high Ti basalts. The low Ti magmas formed at shallow mantle depths in the spinel–garnet field transition zone (60–80 km), whereas the high Ti magmas formed by low degrees of partial melting within the deeper garnet stability field. This observation suggests a deepening of the melting column as the lithosphere thickened due to under-plating and a transition from peak basalt generation to the waning stage. Outstanding issues, which might focus future studies, are also outlined.     

Visibility Analysis In Vision Metrology Network Design

The aim of this paper is to present a method whereby accuracy enhancement of an existing photogrammetric network is achieved through the automatic selection of additional camera stations. The determination of the positions of these 'accuracy fulfilment' camera stations is based upon what has been termed 'visibility uncertainty prediction modelling' of visibility constraints derived from the existing network geometry. Following a review of vision constraints in network design, the concepts of visibility uncertainty prediction and visibility uncertainty spheres are introduced. These provide a mechanism to predict the visibility of current object target points for the new accuracy fulfilment images. This in turn aids in network design improvement. The visibility uncertainty modelling is then illustrated for two close range photogrammetric network configurations, for which the test results demonstrate that the proposed model can reliably predict target visibility with an overall certainty of 75%.     

Optimum design of structures against earthquake by wavelet neural network and filter banks

Optimum design of structures for earthquake is achieved by simulated annealing. To reduce the computational work, a fast wavelet transform is used by means of which the number of points in the earthquake record is decreased. The record is decomposed into two parts. One part contains the low frequency of the record, and the other contains the high frequency of the record. The low‐frequency content is the effective part, since most of the energy of the record is contained in this part of the record. Thus, the low‐frequency part of the record is used for dynamic analysis. Then, using a wavelet neural network, the dynamic responses of the structures are approximated. By such approximation, the dynamic analysis of the structure becomes unnecessary in the process of optimization. The wavelet neural networks have been employed as a general approximation tool for the time history dynamic analysis. A number of structures are designed for optimal weight and the results are compared to those corresponding to the exact dynamic analysis. Copyright © 2004 John Wiley & Sons, Ltd.     

Halley and the London Queen Anne Churches

Edmond Halley's work on two London churches makes them the first buildings planned using modern scientific techniques, argue Jason R Ali and Peter Cunich.     

Determination of aquifer susceptibility to pollution using statistical analysis

 The use of statistical techniques in studying the causes of geochemical variations in aquifers can provide important results which cannot be derived in other ways. In this study, data from the Wadi Shueib catchment area in Jordan is evaluated, using principle component factor and multivariate factor analysis in order to better understand the variablility in groundwater chemistry and evaluate the sources of pollution and the susceptibility of these aquifers to the different sources of pollution. This study clearly demonstrates that these statistical techniques can help determine the various mechanisms causing chemical variation in the aquifers and the relative susceptibility of each aquifer to different types of pollution. Received: 13 March 1996 · Accepted: 18 June 1996