Movement of elements into the atmosphere from coniferous trees in subalpine forests of colorado and Idaho

Exudates from conifer trees, presumably consisting largely of volatile materials, were sampled at 19 subalpine localitites in Colorado and Idaho where anomalous amounts of several metals were determined in vegetation and mull during previous geochemical testing. The trees sampled were lodgepole pine (Pinus contorta), Engelmann spruce (Picea engelmannii) and Douglas fir (Pseudotsuga menziesii). The condensed exudates were passed through No. 40 Whatman filters, and through 5-micron, 0.45-micron, and 0.05-micron average-pore-diameter membrane filters, evaporated to dryness, and each residue was ashed and analyzed by a semiquantitative spectrographic method.The ashed residues of the exudates contain lithium, beryllium, boron, sodium, magnesium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, arsenic, strontium, yttrium, zirconium, molybdenum, silver, lead, bismuth, cadmium, tin, antimony, barium, and lanthanum.The presence of these elements suggests that volatile exudates from vegetation are a medium for the transport of elements in the biogeochemical cycle in subalpine environments. Thus, air sampling and analysis of aerosols derived from volatile exudates may be a useful tool in geochemical exploration.     

Analytical models for the groundwater tidal prism and associated benthic water flux

The groundwater tidal prism is defined as the volume of water that inundates a porous medium, forced by one tidal oscillation in surface water. The pressure gradient that generates the prism acts on the subterranean estuary. Analytical models for the groundwater tidal prism and associated benthic flux are presented. The prism and flux are shown to be directly proportional to porosity, tidal amplitude, and the length of the groundwater wave; flux is inversely proportional to tidal period. The duration of discharge flux exceeds the duration of recharge flux over one tidal period; and discharge flux continues for some time following low tide. Models compare favorably with laboratory observations and are applied to a South Atlantic Bight study area, where tide generates an 11-m³ groundwater tidal prism per m of shoreline, and drives 81 m³ s?^?1 to the study area, which describes 23% of an observational estimate. In a marine water body, the discharge component of any oscillatory benthic water flux is submarine groundwater discharge. Benthic flux transports constituents between groundwater and surface water, and is a process by which pollutant loading and saltwater intrusion may occur in coastal areas.     

A thermodynamic basis for predicting water solubilities in silicate melts and implications for the Low Velocity Zone

A binary asymmetric solution model involving Margules type expansions is used in conjunction with the thermodynamic criterion of equilibrium and published isothermal-polybaric solubility data for basalt, andesite and granitic pegmatite to generate activity coefficients for coexisting water saturated liquid and vapor (containing dissolved solids) phases. Values of Margules parameters so obtained are extrapolated to mantle P-T conditions and show miscibility gaps to persist in all systems at high temperatures. Harding pegmatite alone exhibits complete miscibility at 700°C with the critical parameters P _c=26.1 kb and x _c=0.78 H₂O. Margules parameters when combined with enthalpy, heat capacity and P-V-T data for H₂O in liquid and vapor phases yield values for the solubility of water in magmas at mantle P- T conditions. A consequence of these thermodynamic relations is the fact that solubility isotherms are not monotonically increasing functions of pressure and, in fact, go through maxima. Application of these results to the LVZ (Low Velocity Zone) provides a mechanism whereby the LVZ is stabilized with respect to bulk vertical flow despite the obvious gravitational instability intrinsic to stratified solid-liquid systems.     

SCS-CN and GIS-based approach for identifying potential water harvesting sites in the Kali Watershed,Mahi River Basin,India

The Kali sub-watershed is situated in the semi-arid region of Gujarat, India and forms a part of the Mahi River Watershed. This watershed receives an average annual rainfall of 900mm mainly between July and September. Due to high runoff potential, evapo-transpiration and poor infiltration, drought like situation prevails in this area from December to June almost every year. In this paper, augmentation of water resource is proposed by construction of runoff harvesting structures like check dam, percolation pond, farm pond, well and subsurface dyke. The site suitability for different water harvesting structures is determined by considering spatially varying parameters like runoff potential, slope, fracture pattern and micro-watershed area. GIS is utilised as a tool to store, analyse and integrate spatial and attribute information pertaining to runoff, slope, drainage and fracture. The runoff derived by SCS-CN method is a function of runoff potential which can be expressed in terms of runoff coefficient (ratio between the runoff and rainfall) which can be classified into three classes, viz., high (>40%), moderate (20–40%) and low (<20%). In addition to IMSD, FAO specifications for water harvesting/recharging structures, parameters such as effective storage, rock mass permeability are herein considered to augment effective storage. Using the overlay and decision tree concepts in GIS, potential water harvesting sites are identified. The derived sites are field investigated for suitability and implementation. In all, the accuracy of the site selection at implementation level varies from 80–100%.     

供暖地热开采井筒温度损失模型及应用

地下热水开采过程,井筒周围持续散热导致地热水温度降低形成了井筒温度损失。目前关于井筒温度损失的研究很少,在地热利用方案的编写过程中难以确定设计排量下的井口热水温度,致使后续井网部署及单井配产困难,配产量与实际用热需求易产生供需矛盾。该文首次建立了地热井井筒温度损失模型。借助大型有限元软件COMSOL Multiphysics,以华北油田某潜山区块实际生产数据为例,进行热采井筒温度损失影响因素分析,并分别对实际生产中雾迷山组热水井和高于庄组热水井井筒温度损失进行了预测,为下一步地热开采方案的编制提供借鉴和理论指导。     

Surface water and groundwater dynamic interaction models as guiding tools for optimal conjunctive water use policies in the central plain of Thailand

Many irrigation projects in the central plain of Thailand are not capable of providing sufficient surface water for the cultivation of rice, which is the major cash crop for Thai farmers. To overcome this surface water deficiency, which has been exacerbated in recent years by climate change, groundwater is increasingly being used for irrigation. Thus, large sections of agriculture lands have been converted to conjunctive water use regions. While conjunctive water use may be a suitable option to overcome the temporary water shortages on a short-term basis, it may pose a particular threat to the overall water resources in the long term, if not properly managed. As a remedy, conjunctive water management policies ought to be adopted. Conjunctive water management is basically a tool to optimize productivity, equity, and environmental sustainability through simultaneous management of surface water and groundwater resources. As of now, such a comprehensive approach has not been yet employed in the upper Chao Phraya basin of Thailand, and the present study is one of the first of this kind. The study region is the Plaichumpol Irrigation Project (PIP) where conjunctive water use has become indispensable for meeting the increasing water requirements for farming. To get a first grip on the issue, water demand, supply and actual use in the study area were investigated for the purpose of providing possible guidelines for optimal water exploitation. A numerical groundwater model with a special module for simulating surface-groundwater interaction was applied in the PIP area to understand the impact of the farmer’s irrigation behavior on the dominant hydrological processes that determine the seasonal and multi-annual water availability in the irrigation area. A set-up of different agricultural water allocation schemes that depend on the local weather conditions and the regional management rules are examined by the numerical models. The results of the simulations provide adaptation guidelines for the proper management of the conjunctive water resources, namely, optimal water utilization. The numerical results for the surface groundwater in particular indicated that while the irrigation canals recharge water to the aquifer during both dry and wet season, small amounts of discharge from the aquifers to the canals occur only during the wet season. The analysis of the groundwater balance also showed that the present available groundwater potential is not fully exploited by the farmers, especially during the dry periods of surface water shortage. In contrast, the adoption of an optimal conjunctive management scheme would ensure extra water availability for additional annual rice crops in the region.     

乌蒙山区革香河流域干旱成因及打井找水模式

地下水是乌蒙山区革香河流域重要的饮用水源,由于地下水发育规律复杂,地形起伏巨大,给地下水的有效开发利用带来了诸多困难,广大地区存在干旱缺水问题。文章利用岩溶地下水综合调查—探测—评价方法,查明革香河流域地下水赋存发育规律,揭示流域内干旱频发的成因机理,归纳总结出向斜蓄水构造、背斜蓄水构造、断层蓄水带和断陷盆地蓄水构造四类典型蓄水构造模式,优选了断层阻水、向斜蓄水、岩性界线阻水、上下阻水和地下河径流带五种富水成井区位,并有效应用于严重干旱缺水区的打井找水工作,定井成功率达到70%以上,解决了流域内2万多人的饮水困难问题,有效服务脱贫攻坚。     

Four loss estimates for the Gorkha M7.8 earthquake,April 25, 2015, before and after it occurred

The number of fatalities in the Gorkha M7.8 earthquake of April 25, 2015, has been estimated at four different times as follows. In March 2005, the fatality estimate in this journal was 21,000–42,000 with an assumed magnitude of 8.1 (Wyss in Nat Hazard 34:305–314, 2005). Within hours after this earthquake, the estimated number of fatalities by QLARM was 2000–10,000 using a point source model and M7.9. Four hours later, the estimate was 20,000–100,000, based on a first approximation line source model and assuming children were in school. Children out of school, as this was a weekend day, reduced the fatalities by approximately a factor of two, but was not taken into account for the calculation. The final line source estimates based on M7.8 and M7.9 calculates 800–9300 and 1100–11,200 fatalities, respectively. The official count is about 10,000 fatalities. These estimates were performed using QLARM, a computer tool and world data set on the distribution of people in settlements and containing a model of the buildings present. It is argued here that the loss estimate 10 years before the event being within a factor of 2.1 of the eventual loss count is useful for mitigation planning. With varying quality of information on the source and the attenuation, the estimates of fatalities shortly after the earthquake are accurate enough to be useful for first responders. With full knowledge of the rupture properties and the regional attenuation of seismic waves, the numbers of human losses are estimated correctly.

     

EGMlab, a scientific software for determining the gravity and gradient components from global geopotential models

Nowadays, Global Geopotential Models (GGMs) are used as a routine stage in the procedures to compute a gravimetric geoid. The GGMs based geoidal height also can be used for GPS/levelling and navigation purposes in developing countries which do not have accurate gravimetric geoid models. Also, the GGM based gravity anomaly including the digital elevation model can be used in evaluation and outlier detections schemes of the ground gravity anomaly data. Further, the deflection of vertical and gravity gradients components from the GGMs can be used for different geodetic and geophysical interpretation purposes. However, still a complete and user-friendly software package is not available for universities and geosciences communities. In this article, first we review the procedure for determination of the basic gravity field and gradient components from the GGMs, then general MATLAB based software is presented and applied as a sample case study for determination of gravity components based on the most recent EIGEN-GL04C GRACE model in Sweden. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

矿井突水水源类型判别模型及其系统实现

系统介绍了矿井突水水源快速识别系统的组成,阐述了煤矿突水水源判别的3种数学模型及其适用条件,从应用的角度介绍了该软件的使用步骤。采用该系统软件可高效准确地完成未知样品的水源类型判别,为煤矿安全生产提供决策依据。     

Adsorption isotherms, kinetics and mechanism for the adsorption of cationic and anionic dyes onto carbonaceous particles prepared from Juglans regia shell biomass

In the present study, Juglans regia shells were used to prepare activated carbon by acid treatment method. J. regia shell-based activated carbon was used for the adsorption of two synthetic dyes namely, a basic dye malachite green and an acid dye amido black 10B. The prepared adsorbent was crushed and sieved to three different mesh sizes 100, 600 and 1,000 μm. The adsorbent was characterized by scanning electron microscopy, surface acidity and zero-point charge. Batch experiments were carried out by varying the parameters like initial aqueous phase pH, adsorbent dosage and initial dye concentration. The equilibrium data were tested with Langmuir, Freundlich, Redlich–Peterson and Sips isotherm at three different temperatures 293, 300 and 313 K and it was found that the Freundlich isotherm best fitted the adsorption of both the dyes. Kinetic data were tested with pseudo first-order model and pseudo second-order model. The mechanism for the adsorption of both the dyes onto the adsorbent was studied by fitting the kinetic data with intraparticle diffusion model and Boyd plot. External mass transfer was found to be the rate-determining step. Based on the ionic nature of the adsorbates, the extent of film diffusion and intraparticle diffusion varied; both being system specific. Thermodynamic parameters were also calculated. Finally, the process parameters of each adsorption system were compared to develop the understanding of the best suitable system.     

Dissolved iodine flux from estuarine sediments and implications for the enrichment of iodine at the sediment water interface

During the anaerobic decomposition of organic matter in sediments iodine is released into solution. Three techniques have been applied to independently estimate the resulting flux of soluble I from the sediments to the overlying water of Mud Bay, Georgetown, South Carolina. Flux estimates (summer) range between ~ 5 and 41 μmol/m²/day. The estimates predicted from either the pore water I concentration gradient across the sediment-water interface or the dissolved I production rate are higher than the apparent flux measured directly at the same site. This suggests that I which is released to the pore water under the anoxic conditions below the sediment surface reacts with a sedimentary component at or near the sediment water interface and is lost from solution.     

Climate-induced vegetation dynamics and the Bantu Expansion: Evidence from Bantu names for pioneer trees (Elaeis guineensis,Canarium schweinfurthii,and Musanga cecropioides)

The present article examines whether Late Holocene climate-induced vegetation changes in the Central African forest block may have facilitated the Bantu Expansion. This is done through a body of evidence that is not commonly used for the reconstruction of vegetation dynamics, i.e. language data. The article focuses on common Bantu vocabulary for three pioneer species abundantly present in the Central African pollen record between ca. 2500 and 2000 BP: Musanga cecropioides, Elaeis guineensis, and Canarium schweinfurthii. The geographical distribution patterns of the vernacular names for these pioneer trees add weight to the hypothesis according to which the rainforest contraction that emerged in the first millennium BC had an impact on the way Bantu languages dispersed.     

Holocene landscape evolution and the development of models for human interaction with the environment: An example from the mississippi headwaters region

Integration of a record of Holocene landscape evolution with the cultural record from a multicomponent archaeological site in northern Minnesota has fostered the development of a regional model of human interaction with the changing physical environment. Excavation of 21-CA-169 near Nushka Lake revealed two components, an aceramic Archaic zone where processing of large mammals was the major activity and an upper zone with artifacts suggestive of wild rice processing. Seasonal occupation of the lower zone occurred during a period of falling regional lake levels resulting from natural stream network evolution. The upper zone represents human occupation in a physical and biological setting that was quite different than during earlier occupation. Integration of the geomorphic history of the region along with an interpretation of the types of cultural activities occurring on the changing landscape have provided a model to understand land use and to predict the location of other sites. © 1993 John Wiley & Sons, Inc.     

New models for evolution of magma-poor rifted margins based on a review of data and concepts from West Iberia and the Alps

Direct observation and extensive sampling in ancient margins exposed in the Alps, combined with drill-hole and geophysical data from the present-day Iberia margin, result in new concepts for the strain evolution and near-surface response to lithospheric rupturing at magma-poor rifted margins. This paper reviews data and tectonic concepts derived from these two margins and proposes that extension, leading to thinning and final rupturing of the continental lithosphere, is accommodated by three fault systems, each of them characterized by a specific temporal and spatial evolution during rifting of the margin, by its fault geometry, and its surface response. The data presented in this paper suggest that margin architecture and distribution of rift structures within the future margin are controlled first by inherited heterogeneities within the lithosphere leading to a contrasting behaviour of the future distal and proximal margins during an initial stage of rifting. The place of final break-up appears to be determined early in the evolution of the margin and occurs where the crust has been thinned during a first stage to less than 10 kilometres. During final break-up, the rheology of the extending lithosphere is controlled by the thermal structure related to the rise of the asthenosphere and by serpentinization and magmatic processes.Dedicated to Daniel Bernoulli who taught me to compare the geological record of oceans and orogens     

Accumulation models for coalbed methane in medium- to high-rank coals: examples from the southern Qinshui Basin and southeastern Ordos Basin

The majority of known coalbed methane (CBM) production worldwide comes primarily from high-abundance CBM-enrichment areas or ‘fairways.’ The high-abundance CBM-enrichment areas are primarily characterised by large CBM resources with high single-well productions. CBM accumulation areas from the medium- to high-rank coals in the southern Qinshui Basin and the Hancheng CBM fields in the Ordos Basin were investigated based on regional geological analyses and physical analogue experiments. The results show that gas contents in the study areas increase with depths over the range from approximately 300 to 800 m, while permeabilities generally decrease with depths. Intervals with optimal gas content and permeability exist at a moderate depth along an inclined coal seam under the coupled control of temperature and stress. Brittle–ductile transition deformation increases the permeability and the pore-specific surface areas of coals. The gas content and permeability of the CBM reservoirs are shown to be two key factors determining the formation of high-abundance CBM areas. The coupling of gas enrichment and high permeability provides a favourable combination for CBM accumulation and high production. Combining CBM exploration and development practices in the study areas with physical analogue experiments, two CBM-enrichment models for medium- to high-rank coal have been recognised for different geological conditions, including (1) the model controlled by the depth in the slope zone and (2) the model controlled by the coal brittle and ductile in the deformation zones.     

Sand dune migration as a factor of geoheritage loss: Evidence from the Siwa Oasis (Egypt) and implications for geoheritage management

Anthropogenic damage of geoheritage is documented widely, but natural processes can also lead to geoheritage loss. For instance, sand dune migration causes submergence of unique geological and palaeontological sites in desert environments of the Sahara. The Siwa Oasis in the Western Desert of Egypt boasts rich geoheritage, which is represented in many localities. Three of them in the southern part of the oasis are outcrops of highly-fossiliferous limestones. Palaeontological, sedimentary, palaeogeographical, and geomorphological types of geoheritage are recognized there. Sand dune activity on the study area is registered both visually and with remote sensing techniques. Denudation and destruction of naturally-exposed rocks is documented. Evidence of outcrop submergence with sand is found in all cases. The localities are situated in the pathway of rapid (up to ?10 m/yr) dune migration. One locality may disappear within one–two years. Sand dune migration has to be considered as a factor of geoheritage loss in the Siwa Oasis, and the relevant protection of the studied localities is necessary. Geopark creation and improvement of water use in the oasis can also help significantly, as well as the reference to archaeological experience of excavation and protection of heritage sites submerged by sands. More generally, geoheritage conservation should be integrated with a program for sustainable oasis development.