Distribution of Cu,Co, As,and Fe in mine waste,sediment, soil,and water in and around mineral deposits and mines of the Idaho Cobalt Belt,USA

The distribution of Cu, Co, As and Fe was studied downstream from mines and deposits in the Idaho Cobalt Belt (ICB), the largest Co resource in the USA. To evaluate potential contamination in ecosystems in the ICB, mine waste, stream sediment, soil, and water were collected and analyzed for Cu, Co, As and Fe in this area. Concentrations of Cu in mine waste and stream sediment collected proximal to mines in the ICB ranged from 390 to 19,000 μg/g, exceeding the USEPA target clean-up level and the probable effect concentration (PEC) for Cu of 149 μg/g in sediment; PEC is the concentration above which harmful effects are likely in sediment dwelling organisms. In addition concentrations of Cu in mine runoff and stream water collected proximal to mines were highly elevated in the ICB and exceeded the USEPA chronic criterion for aquatic organisms of 6.3 μg/L (at a water hardness of 50 mg/L) and an LC50 concentration for rainbow trout of 14 μg/L for Cu in water. Concentrations of Co in mine waste and stream sediment collected proximal to mines varied from 14 to 7400 μg/g and were highly elevated above regional background concentrations, and generally exceeded the USEPA target clean-up level of 80 μg/g for Co in sediment. Concentrations of Co in water were as high as in 75,000 μg/L in the ICB, exceeding an LC50 of 346 μg/L for rainbow trout for Co in water by as much as two orders of magnitude, likely indicating an adverse effect on trout. Mine waste and stream sediment collected in the ICB also contained highly elevated As concentrations that varied from 26 to 17,000 μg/g, most of which exceeded the PEC of 33 μg/g and the USEPA target clean-up level of 35 μg/g for As in sediment. Conversely, most water samples had As concentrations that were below the 150 μg/L chronic criterion for protection of aquatic organisms and the USEPA target clean-up level of 14 μg/L. There is abundant Fe oxide in streams in the ICB and several samples of mine runoff and stream water exceeded the chronic criterion for protection of aquatic organisms of 1000 μg/L for Fe. There has been extensive remediation of mined areas in the ICB, but because some mine waste remaining in the area contains highly elevated Cu, Co, As and Fe, inhalation or ingestion of mine waste particulates may lead to human exposure to these elements.     

Parents,permission, and possibility: Young women,college, and imagined futures in Gujarat,India

This article advances critical geographies of youth through examining the spatiality implicit in the imagined futures of young women in rural India. Geographers and other scholars of youth have begun to pay more attention to the interplay between young people’s past, present, and imagined futures. Within this emerging body of scholarship the role of the family and peer group in influencing young people’s orientations toward the future remain underexamined. Drawing on eleven months of ethnographic fieldwork, my research focuses on a first generation of college-going young women from socioeconomically marginalized backgrounds in India’s westernmost state of Gujarat. I draw on the “possible selves” theoretical construct in order to deploy a flexible conceptual framework that links imagined post-educational trajectories with motivation to act in the present. In tracing the physical movement of these young women as they navigate and complete college, my analysis highlights the ways in which particular kinds of spaces and spatial arrangements facilitate and limit intra- and inter-generational contact, and the extent to which this affects young women’s conceptions of the future. I conclude by considering the wider implications of my research for ongoing debates surrounding youth transitions, relational geographies of age, and education in the Global South.     

Models,validation, and applied geochemistry: Issues in science,communication, and philosophy

Models have become so fashionable that many scientists and engineers cannot imagine working without them. The predominant use of computer codes to execute model calculations has blurred the distinction between code and model. The recent controversy regarding model validation has brought into question what we mean by a ‘model’ and by ‘validation.’ It has become apparent that the usual meaning of validation may be common in engineering practice and seems useful in legal practice but it is contrary to scientific practice and brings into question our understanding of science and how it can best be applied to such problems as hazardous waste characterization, remediation, and aqueous geochemistry in general. This review summarizes arguments against using the phrase model validation and examines efforts to validate models for high-level radioactive waste management and for permitting and monitoring open-pit mines. Part of the controversy comes from a misunderstanding of ‘prediction’ and the need to distinguish logical from temporal prediction. Another problem stems from the difference in the engineering approach contrasted with the scientific approach. The reductionist influence on the way we approach environmental investigations also limits our ability to model the interconnected nature of reality. Guidelines are proposed to improve our perceptions and proper utilization of models. Use of the word ‘validation’ is strongly discouraged when discussing model reliability.     

Metals,arsenic, and sulfur in the Aue and Eibenstock granites,Erzgebirge

Average concentrations of Pb, Zn, Cu, and other metals, as well as S and As, were calculated for the Aue granitic cupola, the contact aureole of which hosts the large vein-type uranium deposit of Schlema-Alberoda and the Schneeberg uranium-base metal deposit (Erzgebirge, Germany). The cupola was exposed by mine workings and boreholes, which provided an opportunity to evaluate variations in the abundances of metals in the granites over a vertical interval of more than 2.5 km and estimate their losses in the upper oxidized part of the investigated volume of the cupola (coefficient of iron oxidation, KO _Fe, increases in the granites from bottom to top from 7 to 70%) compared with the lower unaltered and unoxidized part (with a KO _Fe plateau at about 5%). The average concentrations of metals in the upper part of the cupola are lower than those in the lower part by a factor of 2.5 for Pb, 1.56 for Zn, 1.45 for Cu, 1.3 for Co, etc. A similar decrease in the abundances of ore elements along the vertical section associating with the relative epigenetic alteration and oxidation of the granite was previously described by us for U and Th and for the components of high-temperature ores, W, Sn, and Mo. The removal of ore elements from the granite was accompanied by a decrease in the bulk contents of sulfur and arsenic by a factor of 1.35 and 1.65, respectively. The leaching of trace metals from the granites of the upper part of the Aue cupola was followed by their partial redeposition above the cupola in the ore veins of the Schlema and Schneeberg deposits. Original Russian Text ? Vikt. L. Barsukov, N.T. Sokolova, O.M. Ivanitskii, 2006, published in Geokhimiya, 2006, No. 9, pp. 967–982.     

Distribution of copper,cobalt and nickel in ores and host-rocks,Ingladhal, Karnataka,India

Stratiform quartz-sulphide lodes in Ingladhal occur in a typical Precambrian green-stone-belt environment comprising metabasalts, tuff, chert and cherty iron-sulphide formation. Unusually high cobalt contents of metavolcanics and of sulphide minerals in orebodies suggest a consanguinity between ores and rocks. 90% of total nickel, 70% of total cobalt but only 30% of total copper in rocks occur in silicate phases and thus indicate an early separation of copper from cobalt and nickel. Unusually high non-sulphide copper in barren bedded cherts implies availability of Cu-rich solution prior to their lithification. Pyrite in sediments, in volcanics, and in orebodies is characterized by a distinctive pattern of Co-Ni distribution in each case. Partitioning of Co and Ni between coexisting sulphide pairs is complex, but gross equilibrium is indicated. Very high trace metal content of orebody pyrite sharply contrasts with very low such values in pyrite from adjacent sediments and points to a higher temperature of formation of orebodies.     

Fish and invertebrate assemblages in seagrass, mangrove, saltmarsh, and nonvegetated habitats

Many studies compare utilization of different marine habitats by fish and decapod crustaceans; few compare multiple vegetated habitats, especially using the same sampling equipment. Fish and invertebrates in seagrass, mangrove, saltmarsh, and nonvegetated habitats were sampled during May–August (Austral winter) and December–January (Austral summer) in the Barker Inlet-Port River estuary, South Australia. Sampling was undertaken using pop nets in all habitats and seine nets in seagrass and nonvegetated areas. A total of 7,895 fish and invertebrates spanning 3 classes, 9 orders, and at least 23 families were collected. Only one fish species,Atherinosoma microstoma, was collected in all 4 habitats, 11 species were found in 3 habitats (mangroves, seagrass, and nonvegetated), and 13 species were only caught in seagrass and nonvegetated habitats. Seagrass generally supported the highest numbers of fish and invertebrates and had the greatest species richness. Saltmarsh was at the other extreme with 29 individuals caught from two species. Mangroves and nonvegetated habitats generally had more fish, invertebrates, and species than saltmarsh, but less than seagrass. Analyses of abundances of individual species generally showed an interaction between habitat and month indicating that the same patterns were not found through time in all habitats. All habitats supported distinct assemlages although seagrass and nonvegetated assemblages were similar in some months. The generality of these patterns requires further investigation at other estuaries. Loss of vegetated habitats, particularly seagrass, could result in loss of species richness and abundance, especially for organisms that were not found in other habitats. Although low abundances were found in saltmarsh and mangroves, species may use these habitats for varying reasons, such as spawning, and such use should not be ignored.     

赣南大吉山与漂塘花岗岩及有关成矿作用特征对比

对江西南部大吉山和漂塘两个钨矿床有关的花岗岩的岩石化学和微量元素地球化学特征、成因及其与成矿的关系等方面进行了对比研究，认为两者不同的成矿作用特征主要是由于大吉山花岗岩比漂塘花岗岩的分异演化程度更高而造成的。对前人提出的含钨花岗岩、含钽铌花岗岩及花岗岩产出的动力学背景等问题，也进行了一些初步讨论。     

Correlated nucleosynthetic isotopic variability in Cr, Sr, Ba, Sm, Nd and Hf in Murchison and QUE 97008

Acid leaching of the primitive C-chondrite Murchison and O-chondrite QUE 97008 reveal nucleosynthetic anomalies in Cr, Sr, Ba, Nd, Sm and Hf. The anomalies in all but Cr and Sm are best explained by variable additions of pure s-process nuclides to a background nebular composition slightly enriched in r-process isotopes compared to average Solar System material. Leaching leaves a residue in Murchison that is strongly enriched in s-process nuclides with depletions of over 0.1% in ¹³⁵Ba and seven parts in 10,000 in ⁸⁴Sr. If there are p-process anomalies in these two elements, they are lost in the variability caused by different r-, s-process contributions to the normalizing isotopes. The concentration and isotope systematics are consistent with the Ba and Sr isotopic composition in the Murchison residue being strongly influenced by s-process-rich presolar SiC. In general, the nucleosynthetic isotope anomalies are 2- to 5-fold smaller in QUE 97008 than in Murchison. The different magnitudes of isotope anomalies are similar to the difference in matrix abundance between CM and O chondrites consistent with the suggestion that the carriers of nucleosynthetically anomalous material preferentially reside in the matrix and that some of this material has been distributed throughout the O-chondrite minerals as a result of thermal metamorphism.Neodymium, Sm and Hf display variable s-, r-process nuclide abundances as in Ba and Sr, but the anomalies are much smaller (e.g. ε¹⁴⁸Nd, ε¹⁴⁸Sm = −5.7, 2.1, respectively, in Murchison and −0.43, 0.16, respectively in QUE 97008 residues). After correcting Nd and Sm for s-, r-process variability, Sm in whole rock chondrites shows variable relative abundances of the p-process isotope ¹⁴⁴Sm that correlate weakly with ¹⁴²Nd suggesting that the direct p-process contribution to ¹⁴²Nd is small (∼7-9%). Nucleosynthetic variability in Nd explains the range in ¹⁴²Nd/¹⁴⁴Nd seen between C and O, E-chondrites, but not the difference between chondrites and all modern Earth rocks, leaving decay of ¹⁴⁶Sm and a superchondritic Sm/Nd ratio as the likely explanation for Earth’s high ¹⁴²Nd/¹⁴⁴Nd.     

Silicification,silicosis, polymerization,and aluminosis in geocrystallochemistry of silicates and aluminosilicates

Quantum-chemical interpretations of differentiation of the “normal” magmatic melt (the “Bowen's fork”) show certain defects in the traditionally crystallochemical interpretations of mineral structures and of the sequence of crystallization of minerals. The “dynamic unit,” in transitions from phase to phase and from lattice to lattice, proves to be the uncharged SiO₂ molecule and not the SiO₄ tetrahedron, which is but a static architectural detail of crystal structures. Different mechanisms and types of silicification (figs. 3-8), condensation and structures of the chains (figs. 9-14), structures of zeolites and other aluminosilicates (figs. 14, 17, 18), and the quantumchemical representation of corundum, as “molecular” Al₂O₃, illustrate further reevaluations of traditionalism in mineralogy.     

Chemical speciation of Cd,Cu, Pb,and Zn in mixed freshwater,seawater, and brine solutions

A theoretical model was developed to study the chemical speciation of the trace elements Zn, Cd, Cu and Pb aqueous solutions and their responses to variations in ionic strength and complexation. Two mixing solutions were investigated, a freshwater-seawater system and a freshwater-brine system. The brine was a calcium, sodium-chloride solution with a molal ionic strength of two. Trace element associations with the ligands OH^?, Cl^?, CO^2?₃, SO^2?₄, and HCO^?₃ were considered at pHs from 3.5 to 11.0 at 25°C. In general, the relative importance of the various ligand-trace element complexes can be predicted from a comparison of their stability constants. However, the effect of pH on the importance of a given complex is not readily apparent from the stability constants. Freshwater-seawater mixtures, as might be found in a totally mixed estuary, show that seawater composition is the dominant control on chemical complexing. Chloride complexing is similar for lead and zinc in the freshwater-brine mixtures. This similarity may account in part for the association of lead and zinc in strata-bound ore deposits.     

Mega- and giant ripples in the Ganga,Yamuna, and Son Rivers,Uttar Pradesh,India

Sand bars of the three important rivers of the Gangetic Alluvium, namely the Ganga, Yamuna and Son are investigated. Megaripples of undulatory type are the most abundant bed forms present, and are responsible for the development of large-scale cross-bedding, the most common bedding structure present in the area. Giant ripples, with superimposed megaripples are recorded in one sand bar in the Yamuna River. On a steeply sloping point bar in the Ganga River, delta-like lobes have produced foreset bedding oriented towards the main channel, at right angles to the direction of the main flow.     

Determination of REE,Ba, Fe,Mg, Na and K in carbonaceous and ordinary chondrites

Precise determination of REE and Ba abundances in three carbonaceous (Orgueil Cl, Murchison C2 and Allende C3) and seven olivine-bronzite chondrites were carried out by mass spectrometric isotope dilution technique. Replicate analyses of standard rock and the three carbonaceous chondrites demonstrated the high quality of the analyses (accuracies for REE are ±1–2 per cent). Certain carbonaceous chondrite specimens showed small positive irregularities in Yb abundance. The Yb ‘anomaly’ (approximately + 5 per cent relative to the average of 10 ordinary chondrites) in Orgueil may relate to high temperature components. The REE pattern of Guareña (H6) exhibits comparatively extensive fractionation (about factor 2) with a negative anomaly for Eu (17 ± 1 percent) compared to the average H chondrite. This could be interpreted in terms of extensive thermal metamorphism leading to melting.Apart from absolute abundance differences, there appears to be small but recognizable fractionation among the average relative REE abundances of Cl, E, H and L chondrites. However, individual chondrites within these groups showed more or less fractionated REE patterns relative to each other. The distinction between H and L chondrites was well demonstrated in Eu-Sm correlation curves and absolute abundance differences of REE and major elements.Si-normalized atomic ratios of the REE abundances in different kinds of chondrites to those in Orgueil (Cl) chondrite were 0.58 (E), 0.75 (H), 0.81 (L), 1.07 (C2) and 1.32 (C3).     

Roles of xenomelts,xenoliths, xenocrysts,xenovolatiles, residues,and skarns in the genesis,transport, and localization of magmatic Fe-Ni-Cu-PGE sulfides and chromite

Most sulfide-rich magmatic Ni-Cu-(PGE) deposits form in dynamic magmatic systems by partial melting S-bearing wall rocks with variable degrees of assimilation of miscible silicate and volatile components, and generation of barren to weakly-mineralized immiscible Fe sulfide xenomelts into which Ni-Cu-Co-PGE partition from the magma. Some exceptionally-thick magmatic Cr deposits may form by partial melting oxide-bearing wall rocks with variable degrees of assimilation of the miscible silicate and volatile components, and generation of barren Fe ± Ti oxide xenocrysts into which Cr-Mg-V ± Ti partition from the magma. The products of these processes are variably preserved as skarns, residues, xenoliths, xenocrysts, xenomelts, and xenovolatiles, which play important to critical roles in ore genesis, transport, localization, and/or modification. Incorporation of barren xenoliths/autoliths may induce small amounts of sulfide/chromite to segregate, but incorporation of sulfide xenomelts or oxide xenocrysts with dynamic upgrading of metal tenors (PGE > Cu > Ni > Co and Cr > V > Ti, respectively) is required to make significant ore deposits. Silicate xenomelts are only rarely preserved, but will be variably depleted in chalcophile and ferrous metals. Less dense felsic xenoliths may aid upward sulfide transport by increasing the effective viscosity and decreasing the bulk density of the magma. Denser mafic or metamorphosed xenoliths may also increase the effective viscosity of the magma, but may aid downward sulfide transport by increasing the bulk density of the magma. Sulfide wets olivine, so olivine xenocrysts may act as filter beds to collect advected finely dispersed sulfide droplets, but other silicates and xenoliths may not be wetted by sulfides. Xenovolatiles may retard settling of – or in some cases float – dense sulfide droplets. Reactions of sulfide melts with felsic country rocks may generate Fe-rich skarns that may allow sulfide melts to fractionate to more extreme Cu-Ni-rich compositions. Xenoliths, xenocrysts, xenomelts, and xenovolatiles are more likely to be preserved in cooler basaltic magmas than in hotter komatiitic magmas, and are more likely to be preserved in less dynamic (less turbulent) systems/domain/phases than in more dynamic (more turbulent) systems/domains/phases. Massive to semi-massive Ni-Cu-PGE and Cr mineralization and xenoliths are often localized within footwall embayments, dilations/jogs in dikes, throats of magma conduits, and the horizontal segments of dike-chonolith and dike-sill complexes, which represent fluid dynamic traps for both ascending and descending sulfides/oxides. If skarns, residues, xenoliths, xenocrysts, xenomelts, and/or xenovolatiles are present, they provide important constraints on ore genesis and they are valuable exploration indicators, but they must be included in elemental and isotopic mass balance calculations.     

Multichannel deconvolution,MCD, in geophysics and helioseismology

Whenever data sampling is regular along a coordinate in space and/or time, it is relevant to look for approximate shift invariance which casts the forward problem into a convolution formulation. The resulting computations may be speeded up significantly through the Fourier transform. For nonlinear problems the Born approximation in horizontally stratified media leads to just such a result.In many cases the noise is well approximated by a stationary process, and it turns out that the resulting inverse solution is then a multi-channel deconvolution. This formulation allows very fast inversion in the periodic approximation of densely sampled high volume data sets.New applications within geophysical well logging, continuous geoelectrical sounding/profiling, and 3D helioseismic tomography demonstrate the wide applicability of this method.     

Woodfuels,reforestation, and ecodevelopment in highland Madagascar

The populous upland region of this island in the Indian Ocean is heavily dependent on firewood and charcoal to meet its domestic energy requirements. Rural folk collect firewood; city dwellers buy mostly charcoal. Both are used overwhelmingly for cooking. The main wood source is fast-growing but maladaptive eucalyptus and pine planted in reforestation schemes since the turn of the century. A major crisis of woodfuel supply looms in the years ahead that has its roots in population growth, wastefulness, incendiarism, economic retrogression, and administrative tinkering. Even if energy alternatives to woodfuel emerge in the long-term future, environmental rehabilitation remains the key agenda for the region. Reforestation with native trees could simultaneously address the need for wood, soil and water protection, and gene pool maintenance.1) This study was funded by an Africa Research Grant of the Fulbright Program to the senior author in 1983, and by an award through the University of Vermont International Rural Development Program to the junior author. Cooperation on logistical support was graciously provided by Joselyne Ramamonjisoa, Director of the Laboratoire de Géographie at the Université de Madagascar. Jean-Gabriel Rajaonarison, Philippe Belgram, and Pascal Randrianary provided field assistance. Gabriel Ramaroson of the Service des Eaux et Forêts in Antananarivo supplied information on charcoal.     

Long-Term and Seasonal Changes in Nutrients,Phytoplankton Biomass,and Dissolved Oxygen in Deep Bay,Hong Kong

Deep Bay is a semienclosed bay that receives sewage from Shenzhen, a fast-growing city in China. NH₄ is the main N component of the sewage (>50% of total N) in the inner bay, and a twofold increase in NH₄ and PO₄ concentrations is attributed to increased sewage loading over the 21-year period (1986–2006). During this time series, the maximum annual average NH₄ and PO₄ concentrations exceeded 500 and 39 μM, respectively. The inner bay (Stns DM1 and DM2) has a long residence time and very high nutrient loads and yet much lower phytoplankton biomass (chlorophyll (Chl) <10 μg L⁻¹ except for Jan, July, and Aug) and few severe long-term hypoxic events (dissolved oxygen (DO) generally >2 mg L⁻¹) than expected. Because it is shallow (~2 m), phytoplankton growth is likely limited by light due to mixing and suspended sediments, as well as by ammonium toxicity, and biomass accumulation is reduced by grazing, which may reduce the occurrence of hypoxia. Since nutrients were not limiting in the inner bay, the significant long-term increase in Chl a (0.52–0.57 μg L⁻¹ year⁻¹) was attributed to climatic effects in which the significant increase in rainfall (11 mm year⁻¹) decreased salinity, increased stratification, and improved water stability. The outer bay (DM3 to DM5) has a high flushing rate (0.2 day⁻¹), is deeper (3 to 5 m), and has summer stratification, yet there are few large algal blooms and hypoxic events since dilution by the Pearl River discharge in summer, and the invasion of coastal water in winter is likely greater than the phytoplankton growth rate. A significant long-term increase in NO₃ (0.45–0.94 μM year⁻¹) occurred in the outer bay, but no increasing trend was observed for SiO₄ or PO₄, and these long-term trends in NO₃, PO₄, and SiO₄ in the outer bay agreed with those long-term trends in the Pearl River discharge. Dissolved inorganic nitrogen (DIN) has approximately doubled from 35–62 to 68–107 μM in the outer bay during the last two decades, and consequently DIN to PO₄ molar ratios have also increased over twofold since there was no change in PO₄. The rapid increase in salinity and DO and the decrease in nutrients and suspended solids from the inner to the outer bay suggest that the sewage effluent from the inner bay is rapidly diluted and appears to have a limited effect on the phytoplankton of the adjacent waters beyond Deep Bay. Therefore, physical processes play a key role in reducing the risk of algal blooms and hypoxic events in Deep Bay.     

Uranium in Holocene valley-fill sediments,and uranium,radon, and helium in waters,Lake Tahoe—Carson Range area,Nevada and California,U.S.A.

Uraniferous Holocene sediments occur in the Carson Range of Nevada and California, U.S.A., between Lake Tahoe and Carson Valley. The hosts for the uranium include peat and interbedded organic-rich sand, silt, and mud that underly valley floors, fens, and marshes along stream valleys between the crest of the range and the edge of Lake Tahoe. The known uranium accumulations extend along the Carson Range from the area just southeast of South Lake Tahoe northward to the area just east of Carson City; however, they almost certainly continue beyond the study area to the north, west, and south. Due to the young age of the accumulations, uranium in them is in gross disequilibrium with its highly radioactive daughter products. These accumulations have thus escaped discovery with radiation detection equipment in the past. The uranium content of these sediments approaches 0.6 percent; however, the average is in the range of 300–500 ppm. Waters associated with these sediments locally contain as much as 177 ppb uranium. Modest levels of helium and radon also occur in these waters.Uraniferous waters are clearly entering the private and public water supply systems in some parts of the study area; however, it is not known how much uranium is reaching users of these water supplies. Many of the waters sampled in the study area exceed the published health effects guidance level of the Environmental Protection Agency. Regulatory standards for uranium in waters have not been published, however.Much uranium is stored in the sediments along these stream valleys. Estimates for a marsh and a fen along one drainage are 24,000 and 15,000 kg, respectively. The potential effects of man-induced environmental changes on the uranium are uncertain. Laboratory studies of uraniferous sediment rich in organic matter may allow us to evaluate the potential of liberating uranium from such sediments and creating transient increases in the level of uranium moving in water in the natural environment.     

Arsenic in streams,stream sediments,and ground water,fairbanks area,alaska

Arsenic concentrations of less than 5 ppb to as large as 1,260 ppb in stream waters and from 5 ppm to 4,000 ppm in stream sediments were found in the Pedro Dome-Cleary Summit area, Alaska. Waters from three of 20 wells sampled had arsenic concentrations exceeding the U.S. Public Health Service recommended limit of 50 ppb. The high arsenic levels are a consequence of arsenic enrichment in the rocks of the area. Placer and lode-gold mining may increase the arsenic content of the waters by exposing arsenic-containing rocks to surface waters and by increasing the load of arsenic-rich sediments in the streams. Finding these disturbingly large concentrations of arsenic in the waters of the Fairbanks area was the major result of this work, inasmuch as a subsequent study (to be published) revealed arsenic concentrations as large as 10 ppm in domestic wells and prompted an extensive study by Federal and State agencies of the health hazard posed by these arsenic-rich waters.     

Helium,neon, and argon in the iron meteorites Dongling,Nantan and Ningbo

The light noble gases He, Ne and Ar have been measured in the iron meteorites Dongling, Nantan and Ningbo. Dongling and Ningbo show a deficit of cosmic-ray that produced³He of ca. 30% and 10%, respectively, which is argued to be caused by the loss of³H (tritium) from the meteoroids during the time of their exposure to the cosmic radiation. Nantan has the lowest content of noble gases as yet reported for any iron meteorite. Cosmogenic³He and³⁸Ar are only about 1/5000 of those in Dongling which has particularly interesting implications if the two meteorites belong to the same fall^[2]. In addition, Nantan contains nonspallogenic⁴He which we believe to be of radiogenic origin. This radiogenic⁴He, together with a U-content of 2.6×10⁻¹¹ g/g^[20] yields a⁴He retention age close to the cosmic-ray exposure age of Dongling. If Dongling and Nantan were part of the same meteoroid^[2], this result would indicate that He retention in the meteoroid age were 4,500 Ma, a U-content of less than 7.2×10⁻¹³ g/g is required to explain the non-cosmogenic₄He present. An upper limit to the number of transuranium or superheavy-element atoms which have decayed by α-emission in Nantan since onset of He retention is 2×10¹⁰ per gram.     

A catastrophic rockslide-debris flow in Wulong, Chongqing, China in 2009: background, characterization, and causes

On June 5, 2009, a catastrophic rockslide-debris flow occurred at the crest of the Jiweishan Mountain in Wulong, Chongqing, China. Approximately five million cubic meters of limestone blocks slid along a weak interlayer of bituminous and carbonaceous shale. The source mass descended from the upper part of the slope rapidly, crossing a 200-m wide and 50-m deep creek in front of it. Blocked by the opposite steep creek wall, the sliding mass changed its direction and traveled a further 2.2 km along the creek in debris-flow mode, finally forming a large accumulation zone with an average depth of 30 m. This is one of the most catastrophic rockslide events in recent years in China. It buried 12 houses and the entrance of an iron mining tunnel where some 27 miners were working inside. Ten people died, 64 missing, and eight wounded. Immediately after this disaster happened, the government organized an expert team to assist the rescue work. As one of the geological experts, the author did a lot of field investigations and collected first-hand information. Multi-methods including the remote sensing, 3D laser scanning, geophysical exploration, and numerical modeling were used for analyzing the characteristics and the triggering mechanism of the Wulong rockslide. The preliminary investigation results reveal that this rockslide with poor geological conditions was mainly induced by the gravitation and the karst effect and also affected by the previous mining activities. The research in this paper is meaningful and useful for further research on such kind of rockslides that are geologically similar to the Wulong rockslide.