Characterization of mesostasis regions in lunar basalts: Understanding late‐stage melt evolution and its influence on apatite formation

Recent studies geared toward understanding the volatile abundances of the lunar interior have focused on the volatile‐bearing accessory mineral apatite. Translating measurements of volatile abundances in lunar apatite into the volatile inventory of the silicate melts from which they crystallized, and ultimately of the mantle source regions of lunar magmas, however, has proved more difficult than initially thought. In this contribution, we report a detailed characterization of mesostasis regions in four Apollo mare basalts (10044, 12064, 15058, and 70035) in order to ascertain the compositions of the melts from which apatite crystallized. The texture, modal mineralogy, and reconstructed bulk composition of these mesostasis regions vary greatly within and between samples. There is no clear relationship between bulk‐rock basaltic composition and that of bulk‐mesostasis regions, indicating that bulk‐rock composition may have little influence on mesostasis compositions. The development of individual melt pockets, combined with the occurrence of silicate liquid immiscibility, exerts greater control on the composition and texture of mesostasis regions. In general, the reconstructed late‐stage lunar melts have roughly andesitic to dacitic compositions with low alkali contents, displaying much higher SiO₂ abundances than the bulk compositions of their host magmatic rocks. Relevant partition coefficients for apatite‐melt volatile partitioning under lunar conditions should, therefore, be derived from experiments conducted using intermediate compositions instead of compositions representing mare basalts.     

Micro-level perception to climate change and adaptation issues: A prelude to mainstreaming climate adaptation into developmental landscape in India

Climate change adds another dimension of challenges to the growth and sustainability of Indian agriculture. The growing exposure to livelihood shocks from climate variability/change and limited resource base of the rural community to adapt has reinforced the need to mainstream climate adaptation planning into developmental landscape. However, a better understanding of micro-level perceptions is imperative for effective and informed planning at the macro-level. In this paper, the grass-root level perspectives on climate change impacts and adaptation decisions were elicited at farm level in the Moga district of Punjab and Mahbubnagar district of Telangana, India. The farmers opined that the climatic variability impacts more than the long-term climate change. They observed change in the quantum, onset and distribution of rainfall, rise in minimum as well as maximum temperature levels, decline in crop yield and ground water depletion. The key socio-economic effects of climate change included decline in farm income, farm unemployment, rural migration and increased indebtedness among farmers. In order to cope with climate variability and change thereon, farmers resorted to adaptation strategies such as use of crop varieties of suitable duration, water conservation techniques, crop insurance and participation in non-farm activities and employment guarantee schemes. Farmers’ adaptation to changing climate was constrained by several technological, socio-economic and institutional barriers. These include limited knowledge on the costs–benefits of adaptation, lack of access to and knowledge of adaptation technologies, lack of financial resources and limited information on weather. Besides, lack of access to input markets, inadequate farm labour and smaller farm size were the other constraints. Further, on the basis of the grass-root elicitation a ‘Need-Based Adaptation’ planning incorporating farmers’ perceptions on climate change impacts, constraints in the adoption of adaptation strategies and plausible adaptation options were linked with the most suitable ongoing programmatic interventions of the Government of India. The study concluded that micro-level needs and constraints for various adaptation strategies and interventions should be an integral part of the programme development, implementation and evaluation in the entire developmental paradigm.     

Permafrost and geotechnical investigations in Nalaikh Depression of Mongolia

Mongolia is a land-locked country in Central Asia, located between Russia and China. The country's high altitude results in cold, dry, and harsh climatic conditions with permafrost being widespread through the territory. Although the capital city Ulaanbaatar is situated in an area with discontinuous permafrost, the downtown section has recently seen a disappearance of permafrost due to an underground central heating system. During the last decade, expansion of the suburbs toward the Nalaikh Depression has resulted in construction of a new residential complex (Urgakh Naran), construction materials trading center, cement factory and agricultural products market. In the next 10 years, projects such as a university campus, logistics center, residential complex, railway and highway extensions connecting Russia and China have been planned. Engineering-geological and geotechnical investigations have been conducted for these construction projects. This paper presents some of the results determining the engineering geocryological conditions of Nalaikh district and offers foundation design options.     

Jump relations across a shock in non-ideal gas flow

Generalized forms of jump relations are obtained for one dimensional shock waves propagating in a non-ideal gas which reduce to Rankine-Hugoniot conditions for shocks in idea gas when non-idealness parameter becomes zero. The equation of state for non-ideal gas is considered as given by Landau and Lifshitz. The jump relations for pressure, density, temperature, particle velocity, and change in entropy across the shock are derived in terms of upstream Mach number. Finally, the useful forms of the shock jump relations for weak and strong shocks, respectively, are obtained in terms of the non-idealness parameter. It is observed that the shock waves may arise in flow of real fluids where upstream Mach number is less than unity.     

The Chandrayaan-1 X-ray Spectrometer: First results

We present X-ray fluorescence observations of the lunar surface, made by the Chandrayaan-1 X-ray Spectrometer during two solar flare events early in the mission (12th December 2008 and 10th January 2009). Modelling of the X-ray spectra with an abundance algorithm allows quantitative estimates of the MgO/SiO₂ and Al₂O₃/SiO₂ ratios to be made for the two regions, which are in mainly basaltic areas of the lunar nearside. One of these ground tracks includes the Apollo 14 landing site on the Fra Mauro Formation. Within the 1σ errors provided, the results are inside the range of basaltic samples from the Apollo and Luna collections. The Apollo 14 soil composition is in agreement with the results from the January flare at the 1σ uncertainty level. Discrepancies are observed between our results and compositions derived for the same areas by the Lunar Prospector gamma-ray spectrometer; some possible reasons for this are discussed.     

Measurements of radon flux and soil-gas radon concentration along the Main Central Thrust, Garhwal Himalaya, using SRM and RAD7 detectors

Radon in the Earth’s crust or soil matrix is free to move only if its atoms find their way into pores or capillaries of the matrix. ²²²Rn atoms from solid mineral grains get into air, filling pores through emanation process. Then ²²²Rn enters into the atmosphere from air-filled pores by exhalation process. The estimation of radon flux from soil surface is an important parameter for determining the source term for radon concentration modeling. In the present investigation, radon fluxes and soil-gas radon concentration have been measured along and around the Main Central Thrust (MCT) in Uttarkashi district of Garhwal Himalaya, India, by using Scintillation Radon Monitor (SRM) and RAD7 devices, respectively. The soil radon gas concentration measured by RAD7 with soil probe at the constant depth was found to vary from 12 ± 3 to 2330 ± 48 Bq·m^?3 with geometrical mean value of 302 ± 84 Bq·m^?3. Th significance of this work is its usefulness from radiation protection point of view.     

Mapping bedrock lithologies through in situ regolith using retained element ratios: a case study from the Agnew-Lawlers area,Western Australia

Large, high-quality multi-element geochemical datasets are becoming widely available in the exploration industry, and afford excellent opportunities to investigate geochemical processes. A dataset of over 2500 analyses of unweathered and variably weathered mafic and ultramafic rocks for over 50 elements has been collected by Gold Fields Ltd. in the auriferous Agnew-Lawlers area of the eastern Yilgarn Craton of Western Australia. This dataset is used to investigate changes in element abundances and inter-element ratios through varying degrees and styles of weathering in an area of thick regolith characterised by deep in situ weathering. Systematic interrogation of the data, using lithostratigraphic controls derived from regional mapping and geophysics, reveals that a suite of elements, including Ti, Al, Zr, Th, La, Sc and Nb, and to a lesser extent Cr and Ni, behave as essentially immobile components during saprolite formation. In some cases diagnostic element ratios persist into siliceous duricrust. Ratios of these elements are used as reliable discriminants of bedrock type, and delineate features such as cryptic layering within fractionated sills and subtle geochemical variants in a sequence of tholeiitic and komatiitic basalts. Mapping on the basis of discriminant element ratios greatly extends previous trace-element ratio-based schemes for rock type discrimination. The potential to determine several of these elements with adequate precision and accuracy using portable XRF technology opens a potentially useful technique for rapid geochemical bedrock mapping in residual terrains.     

Numerical and multivariate stochastic approaches to characterize flow in a constructed wetland basin

Reduction in specific and viscous dissipation rate in surface waters by flow control and contaminant removal are the goals of constructed wetlands. A two-dimensional simulation study on surface flow through a constructed wetland in Guilin, China is performed. The flow through the wetland is modeled and dynamically simulated by distinct case studies by varying both inlet width and inflow rate. Nonlinear increase in peak dynamic pressure and specific dissipation rates as a function of increasing inflow rate is reported for the different cases studied. The results of the numerical models confirm an increase in viscous dissipation, shear stress and dynamic pressure within the wetland with increase in inflow rate. These modeling results are used as inputs for performing a statistical data analysis. Further, a multivariate stochastic statistical framework has been proposed for the prediction of dissipation as a function of variables including inflow rate, inlet geometry and wall shear stress. Multivariate and variance analysis is performed to validate the appropriateness of the theoretical models proposed. Results provide simplified meaningful suggestions to constructed wetland design and related applications.     

Consolidation Parameters Interpretation of CPTU Dissipation Data Based on Strain Path Theory for Soft Jiangsu Quaternary Clays

When a piezocone (CPTU) penetrates the ground, pore pressures are set up due to the stress changes. Pore pressure dissipation occurs in the subsequent consolidation process in a manner dependent on the initial stress distribution. The process of analysis can be used to interpret the consolidation parameters from CPTU data based on strain path approach. For the two approaches to the CPTU analysis, the Houlsby and Teh method used an elastic-plastic model, while the Levadoux and Baligh solution used parameters specifically appropriate for Boston Blue Clay. This article discusses a comparison between the two theoretical predictions and field CPTU measurements deployed in Jiangsu (China) Quaternary clays. The values of the coefficient of consolidation calculated from the two methods are then compared with high-quality laboratory tests. Both theoretical predictions provide good agreement for the shape of the dissipation curve, but the predicted c _h values are different and thought should indeed be given to the use of an appropriate value of G/s _u.     

Yield estimation of summer crops grown in a mixed cropping area,a spectral growth curve profile approach

Estimation of crop production in advance of the harvest has been an intensively researched field in agriculture. Spectral parameters derived from the spectral growth profile being indicator of growth and development characteristics of the crop have a direct utility in crop-yield modeling. The present study is undertaken in a mixed cropping area of Karveer taluka, Kolhapur district, Maharashtra, to assess feasibility of multi-date moderately coarse WiFS data in developing spectral growth curves following Badhwar model (1980) for summer groundnut and paddy. The analysis highlighted potential of moderately coarse resolution WiFS data in discriminating the crops grown in fragmented conditions, provided detailed and adequate ground truth is used. The regression models using spectral parameters explained 94 % variation in paddy yield. However, model using ground information as peak LAI in addition to spectral variables, could explain 91 % variation in groundnut yield; thus for prediction of low-yielding and poorly managed crop a convergent model is essential. Vegetative growth rate during the pre-heading phase and total growing season absorbed photosynthetically active radiation (APAR) indicated by the area under the curve are the main predictors.