bluuebunny/crossref_metadata_2025 huggingface dataset:
Holocene Changes in Deep Water Circulation Inferred From Authigenic Nd and Hf Isotopes in Sediment Records From the Chukchi‐Alaskan and Canadian Beaufort Margins
Authors: Deschamps Charles‐Edouard , Montero‐Serrano Jean‐Carlos , St‐Onge Guillaume , Poirier André
Published: June 2019

The rare earth element concentrations and radiogenic isotope (Sr‐Nd‐Hf) compositions measured in bulk sediment leachates, together with bulk and clay mineralogical data, from two piston cores recovered in the Canadian Beaufort (AMD0214‐02PC) and Chukchi‐Alaskan (HLY0501‐01JPC) margins were studied to investigate changes in the weathering regimes and deep water circulation during the Holocene. The coupled evolutions of the Nd and Hf isotopic compositions (expressed in epsilon units: ɛNd and ɛHf, respectively) are in good agreement with modern seawater and bulk sediment leachate data from Pacific water, Atlantic water, and the Mackenzie River. This agreement supports the idea that boundary exchange and brine formation likely play a significant role in the ɛNd and ɛHf values of the bottom waters in the western Arctic Ocean. The ɛNd and ɛHf records from the Canadian Beaufort and Chukchi‐Alaskan margins reveal changes toward more radiogenic values from the early to late Holocene. Based on the ɛNd and ɛHf records, we suggest that the unradiogenic values are not controlled by water mass provenance and mixing but rather by provenance and a change in the weathering regime in the Mackenzie and Yukon drainage basins during the early to mid‐Holocene. In contrast, the more radiogenic ɛNd and ɛHf values in the Chukchi‐Alaskan margin and the mineralogical records in the late Holocene have primarily been controlled by an increase in the contributions of seawater and detrital particles from the Bering Sea via the Bering Strait inflow, which is likely related to major changes in the Pacific Ocean‐atmospheric dynamics.
The Ex‐Post Cost‐Effectiveness of Nitrogen Load Reductions From Nine Countries to the Baltic Sea Between 1996 and 2010
Authors: Häggmark Svensson Tobias , Elofsson Katarina
Published: June 2019

Policy efforts to improve Baltic Sea water quality will be expensive if the ambitious targets agreed are to be achieved. The aim of this study is to evaluate the ex‐post cost‐effectiveness of nitrogen load reductions to the Baltic Sea made between 1996 and 2010. We first calculate the counterfactual change in nitrogen load to the Baltic Sea and compare to observed loads. The costs of the net reductions are evaluated using a Baltic‐wide cost‐effectiveness model, which includes a wide set of nitrogen abatement measures in the littoral countries. Results show that the net nitrogen reductions achieved through environmental policy, about 145,000 tons total nitrogen, could have been obtained at 12% of the realized cost, through reallocation of abatement between countries. The total budget spent on abatement could, if used in a cost‐effective manner, be sufficient for a doubling of the net nitrogen load reduction. Milestone targets, in combination with a compensation scheme between countries, could help to reduce policy costs.
Women in Oceanography Still Navigate Rough Seas
Authors: Duncombe Jenessa
Published: June 2019

Female scientists have weathered bias, lack of support, and unsafe work environments since the dawn of oceanography. Could recent initiatives, technology, and awareness chart the way to safer waters?
Substorm‐Related Near‐Earth Reconnection Surge: Combining Telescopic and Microscopic Views
Authors: Sergeev V. A. , Apatenkov S. V. , Nakamura R. , Baumjohann W. , Khotyaintsev Y. V. , Kauristie K. , van de Kamp M. , Burch J. L. , Ergun R. E. , Lindqvist P.‐A. , Torbert R. , Russell C. T. , Giles B. L.
Published: June 2019

A strong ~11‐min‐long surge of the lobe reconnection was observed during a substorm on the tailward side of the near‐Earth neutral line. In the southern lobe near the reconnection separatrix the MMS spacecraft observed short‐duration earthward electron beams providing the local Hall current, tailward propagating Alfven wave (AW) bursts with Poynting flux up to 10−4 W/m2, and large‐amplitude E field spikes (e‐holes) and low hybrid waves. The reconnection surge was accompanied by substorm current wedge formation and fast poleward expansion of auroral bulge‐related westward electrojet in the conjugate ionosphere. During its meridional crossing above the expanding bulge the Metop‐2 spacecraft observed an intense energetic precipitation spike near the expected X line foot point and confirmed the dipolarized character of magnetic field lines inside of the bulge. Globally the observed average reconnection rate ( ~3.3 mV/m) was sufficient to produce the magnetic flux increase in the bulge, associated with observed fast poleward expansion (about 6° latitude in 5 min).
Raman spectroscopic screening of high and low molecular weight fractions of human serum
Authors: Parachalil Drishya Rajan , Bruno Clément , Bonnier Franck , Blasco Hélène , Chourpa Igor , McIntyre Jennifer , Byrne Hugh J.
Published: June 2019

This study explores the suitability of Raman spectroscopy as a bioanalytical tool, when coupled with ultra-filtration and multivariate analysis, to detect imbalances in both high molecular weight and low molecular weight fractions of the same samples of human patient serum, in the native liquid form.
Superhydrophobic states of 2D nanomaterials controlled by atomic defects can modulate cell adhesion
Authors: Jaiswal Manish K. , Singh Kanwar Abhay , Lokhande Giriraj , Gaharwar Akhilesh K.
Published: June 2019

We report the synthesis of superhydrophobic two-dimensional (2D) transition metal dichalcogenides by modulation of the degree of atomic defects. The presence of atomic vacancies in 2D molybdenum disulfide (MoS2) nanoassemblies dictated hydrophilic-to-hydrophobic transition and subsequent cell adhesion.
Waste not, want not: CO2 (re)cycling into block polymers
Authors: Raman Sumesh K. , Raja Robert , Arnold Polly L. , Davidson Matthew G. , Williams Charlotte K.
Published: June 2019

A new catalysis combining two different polymerisation mechanisms but using a single catalyst allows the efficient recycling of CO2 and block polymer formation.
A counter ion triggers stabilization of two geometrical isomers of a Ni(ii) dication diradical porphyrin dimer: the role of anion–π interactions
Authors: Pandey Anjani Kumar , Usman Mohammad , Rath Sankar Prasad
Published: June 2019

Two isomers of a nickel(ii)porphyrinato dication diradical, isolated selectively in pure form, are stabilized exclusively by anion–π interactions, have unique and distinct electronic and spectroscopic features and display an anion-induced charge/electron transfer phenomenon.
Exclusive imidazole ligation to CuIII2O2 and CuIIICuII2O2 cores
Authors: Keown William , Large Tao A. G. , Chiang Linus , Wasinger Erik C. , Stack T. Daniel P.
Published: June 2019

Direct oxygenation of imidazole-ligated Cu(i) generates dinuclear and trinuclear Cu(iii) species with exclusive imidazole ligation.
Oxygen vacancy-engineered Fe2O3 nanocubes via a task-specific ionic liquid for electrocatalytic N2 fixation
Authors: Zhang Chenyun , Liu Shuai , Chen Tingting , Li Zhonghao , Hao Jingcheng
Published: June 2019

A task-specific ionic liquid strategy was proposed for designing oxygen vacancy-rich α-Fe2O3 nanocubes toward excellently electrocatalytic N2 fixation to NH3.
2-Iodoxybenzoic acid ditriflate: the most powerful hypervalent iodine(v) oxidant
Authors: Yusubov Mekhman S. , Soldatova Natalia S. , Postnikov Pavel S. , Valiev Rashid R. , Yoshimura Akira , Wirth Thomas , Nemykin Victor N. , Zhdankin Viktor V.
Published: June 2019

A new powerful hypervalent iodine(v) oxidant, a ditriflate derivative of 2-iodoxybenzoic acid (IBX), was prepared by the reaction of IBX with trifluoromethanesulfonic acid and characterized by single crystal X-ray crystallography.
Transport of hyperpolarized samples in dissolution-DNP experiments
Authors: Kiryutin Alexey S. , Rodin Bogdan A. , Yurkovskaya Alexandra V. , Ivanov Konstantin L. , Kurzbach Dennis , Jannin Sami , Guarin David , Abergel Daniel , Bodenhausen Geoffrey
Published: June 2019

The magnetic field strength during sample transfer in dissolution dynamic nuclear polarization influences the resulting spectra.
Wideband circularly‐polarised high‐gain diversity antenna loaded with metasurface reflector for small satellite applications
Authors: Ameen M. , Ahmad O. , Chaudhary R.K.
Published: June 2019

This Letter demonstrates the design of a two‐element polarisation diversity antenna, applicable for modern small satellite application systems. The intended antenna mainly consists of two monopole radiators loaded with metasurface reflector as a ground plane. The dimensions of the radiator antenna are 40 × 22 × 1.6 mm3. The antenna measured results offers a wider S11 bandwidth of (2.23–2.91 GHz) and wider axial ratio bandwidth (ARBW) of (2.16–2.92 GHz) with a common S11 and ARBW of 26.45% is obtained. A maximum gain of 7.02 dBic and isolation better than 14.5 dB is observed along with the operating frequency range. The antenna provides an ARBW(< 3 dB) and gain (> 2.38 dBic) for theta = ± 45°, for all phi values along with the complete operating frequency range. Also, the antenna port‐1 provides left‐handed circular polarisation and port‐2 provides right‐handed circular polarisation radiation with directional radiation characteristics.
Efficiency‐based design optimisation of a double‐sided LCL compensated wireless power transfer system
Authors: Yao Yousu , Wang Yijie , Álvarez José Marcos Alonso , Liu Xiaosheng , Cheng Haisong , Xu Dianguo
Published: June 2019

The double‐sided inductor–capacitor–inductor (DS‐LCL) compensation topology has been extensively employed in wireless power transfer (WPT) systems owing to its advantages including zero voltage switching operation, constant current output, and no reactive power exchange between the primary and secondary sides. However, in most cases, equality of the primary and secondary coupling inductances is not optimal from the perspective of power transfer efficiency (PTE). This study presents an efficiency‐based design optimisation method for DS‐LCL compensated WPT system to obtain the highest PTE. The loss sources, as well as their impact on the PTE, are analysed. The analytical equivalent series resistance models of the efficiency‐related loss sources are built and validated by practical measurements. The optimisation procedures are given as well. Two 1 A/200 W WPT prototypes are fabricated, tested, and compared, where one of them is designed in terms of the proposed optimisation method, whereas the other is designed in a conventional manner. The power loss on coupling coils of the optimised system is 7.49 W, 21.5% lower than that of the conventional system (9.54 W). The system overall efficiency is increased from 91.65% to 92.67% by utilising the proposed optimisation method.
Al modification as indicator of current filaments in IGBTs under repetitive SC operation
Authors: Mysore Madhu Lakshman , Bhojani Riteshkumar , Kowalsky Jens , Lutz Josef , Baburske Roman , Schulze Hans‐Joachim , Niedernostheide Franz‐Josef
Published: June 2019

This work investigates modification on the top‐side aluminium (Al) metallisation of 1.2 kV insulated‐gate bipolar transistors (IGBTs) under repetitive short‐circuit (SC) type‐I measurements for two different parasitic inductances of 45 and 380 nH. The presence of current–density filaments starting at the collector side during SC leads to local temperature increase of the emitter metallisation and thus to modification of the top Al surface in the pattern of the current filaments. Here, two techniques thermo‐reflectance microscopy, which can detect the surface temperature during repetitive short circuits directly and Al modifications after repetitive SC with analysis under optical microscope after the test have been considered. At 45 nH, with different DC‐link voltages from 300 to 600 V, the Al modification pattern is non‐uniform and it becomes uniform for VDC>600 V. However, for 380 nH parasitic inductance and for DC‐link voltages 300 and 400 V, the Al reconstruction shows a non‐uniform pattern and becomes uniform for VDC≥500 V. The SC simulations were performed by using a simplified front‐side IGBT structure using variable DC‐link voltages and inductances to reproduce the filament behaviour.
Nature of chemical composition diversity of the East Ttransbaikalia salt lakes (Russia)
Authors: Borzenko Svetlana
Published: June 2019

We have developed a new concept for the formation of geochemical types of salt lakes which explains the nature of their different chemical composition under close landscape-climatic and geological-geochemical conditions. The extensive field hydrogeochemical material and thermodynamic calculations demonstrate that in addition to evaporation, the interaction with rocks plays a great role in the formation of the composition of lakes. This interaction begins in the catchment area of a particular lake and continues directly in the lake. Such processes are most widespread in soda lakes, which is confirmed by the presence of the highest pH values (9.0-10.7). Besides, one of the most important processes is sulfate reduction, which results in hydrogen sulphide in lakes fundamentally changes the geochemical environment from oxidizing to reducing one and leads to a change in the oxidation state of many elements, changing their migration ability and, therefore, the ability for concentration or binding by secondary minerals. The presence of an oxidizing environment and sulphides in rocks gives additional sources for sulfates, which ensures the formation of sulfate-type lakes.
Spheroidal weathering of columnar-jointed basalt of the Ogura lava in the Takurayama Volcano, western Japan
Authors: Hirata Yasuto , Chigira Masahiro
Published: June 2019

Spheroidal weathering is an important form of rock weathering and has been attributed to chemical weathering from joint surfaces. However, the effects of the original rock structures on the processes of spheroidal weathering have not been well addressed. A columnar-jointed basalt contains primary structures that resulted from cooling, which exerted strong controls on the development of weathering with hard crusts. The primary structures were small-pore-size layers beneath the surfaces of columnar joints and some cross joints. Weathering of plagioclase was less intense in the small-pore-size layers, resulting in the exfoliation of surface parts of the layers and internal cracks.
Impact of sulfuric acid on carbonate dissolution in the upper-middle reaches of Wujiang River
Authors: Huang Qibo , Qin Xiaoqun , Zhang Liankai , Liu Pengyu
Published: June 2019

Due to rapid population and economic growth in recent years, the Wujiang River has been heavily impacted by anthropogenic activities. Of particular concern is the increase in SO42- concentration of the river water from various anthropogenic sources. The results showed that the major cations of groundwater and surface water were Ca2+ and Mg2+ (>70% of the cation concentration), and the main anions were HCO3-and SO42-(>85% of the anion concentration). In groundwater, the contributions of carbonate dissolution to Ca2++Mg2+ by sulfuric acid ranged from 20.6% to 92.9% (average 51.5%); and to HCO3- from 11.5% to 86.7% (average 36.9%). In the surface water, the contributions of carbonate dissolution to Ca2++Mg2+ ranged from 56.1% to 94.6% (average 76.9%); and to HCO3from 39.0% to 89.7% (average 64.2%). Our results demonstrate that besides carbonic acid, sulfuric acid also plays an important role on carbonate rock weathering, and influences the hydrochemistry of both groundwater and surface water in the Wujiang River drainage.
The geochemistry of water and gas phases from high pCO2 sparkling springs within the northern Sikhote-Alin ridge region (Russian Far East)
Authors: Kharitonova Natalia , Chelnokov Georgy , Bragin Ivan , Nakamura Hitomi , Iwamori Hikaru , Morikawa Noritoshi , Korzun Anna
Published: June 2019

Two types of cold CO2 rich groundwaters are located within the northern part of the Sikhote-Alin ridge: the first type is a Ca–Mg–HCO3 water with low TDS content (≤ 1.7 g/l) and high concentrations of Fe2+, Mn2+, Ba2+, and SiO2, whilst the second type is a Na–HCO3 water with a high TDS content (≈ 14 g/l) and elevated concentrations of Li+, Btot, Sr2+, Br–, and I–. A notable feature of these waters is a predominance of CO2 in the gas phase (up to 99 vol. %) and low contents of other gases (CH4, N2, O2, etc.). The origins of both water types can be identified on the basis of water (δD, δ18O) and gas (δ13C, 3He/4He, 4He/20Ne) isotopic compositions considered in the context of the geology and hydrology of the region.
Characteristics of interactions between black shale and water
Authors: Liao Xin , Wang Kangji , Wu Xiyong , Ling Sixiang , Guo Deping , Xi Yingwei
Published: June 2019

Some geological engineering problems are caused by weathering of black shale within dispersed sulfide minerals (mainly pyrite), in which some weathering products such as acid water and expansive sulfates play an important role. These effects are essentially manifested through oxidation of sulfide minerals. Complex chemical reactions occur simultaneously and influence mutually in water-rock interaction process. Chemical weathering of black shale is a factor leading to engineering problems such as landslides and acid corrosion. The objectives of present study are to understand the process of water-rock interactions between black shale and water. The semi-immersion simulation experiment is mainly used to explore the chemical weathering characteristics of black shale under natural conditions.
Post-mining groundwater geochemistry evolution in on the Levikha sulfide deposits of the Middle Urals (Russia)
Authors: Rybnikova Liudmila S. , Rybnikov Petr A.
Published: June 2019

Mining of volcanogenic copper pyrite deposits of the Middle Urals leads to the rock disintegration, their grinding, increasing the interaction surface. Sulfide minerals are oxidized by interaction with oxygen-enriched meteoric water and secondary minerals are formed (crystallo-hydrates of sulphates, hydroxides). Here technogenic zone hypergene (sulfuric acid weathering crust) is being formed. Once the water pumping activities are finished, the piezometric level recovers its position decreasing the unsaturated zone created during the mining activity, this increases the water-rock ratio increasing the amount of suppliers of sulphates, iron, non-ferrous metals and other elements to groundwater. It defines a low rate of rehabilitation of mining areas after the completion of mining and cessation of dewatering. The regularities of acidic water formation after filling the depression cone are investigated on the abandoned copper mines of the Middle Urals (Russia). The longevity of formation of extremely acidic and polluted waters is determined by the degree of saturation of the supergene zone with secondary minerals and the intensity of water exchange. Seasonal decrease in the component’s concentrations t in the period of winter and summer low water was recorded. The unstable character of groundwater components changes with a half-life of more than 5 thousand days is established. The duration of rehabilitation and restoration of groundwater quality will be at least a hundred years.
The evolution of the ecosystems of thermokarst lakes of the Bolshezemelskaya tundra in the context of climate change
Authors: Shirokova Liudmila , Ivanova Irina , Manasypov Rinat , Pokrovsky Oleg , Chupakov Artem , Iglovsky Stanislav , Shorina Natalia , Zabelina Svetlana , Gofarov Mikhail , Payandi-Rolland Dahedrey , Chupakova Anna , Moreva Olga
Published: June 2019

In the conditions of climate warming, the thawing of permafrost can provoke the formation of new thermokarst lakes and subsidence, which facilitates the removal of organic matter from thawed peat into natural waters. Hydrochemical studies of surface waters of the Bolshezemelskaya tundra have demonstrated the exponential dependence of the physicochemical parameters on the size of the water body (peat subsidence, thaw ponds, small lakes, thermokarst lakes). The hydrochemical features of thermokarst lakes of the Bolshezemelskaya tundra are determined by high content of DOC, surface runoff and the thickness of peat deposits. Measurements of concentrations and fluxes of methane showed that all studied water bodies of the Bolshezemelskaya tundra are oversaturated with CH4, and depressions, subsidence, and small water bodies (<100 m2) are characterized by the highest concentrations of DOCs. The contribution of these small reservoirs to the total coverage of the surface of the Bolshezemelskaya tundra area is significant, and their consideration can greatly change the assessment of methane fluxes from the arctic tundra.
The rare-earth elements distribution in the Bazhenov shales
Authors: Kazak Ekaterina , Kharitonova Natalia , Sorokoumova Yana
Published: June 2019

The rare-earth elements and yttrium (REY) distribution data with depth in the Bazhenov formation are given for the case of the one well in the Nizhnevartovsk arch of the Western Siberia, Russian Federation. According to the correlation analysis, it was found that REY (mainly LREE) is concentrated in apatite more than in clays or plagioclase, while HREE is preferably accumulated in clay minerals. It was estimated that the water extracts from the Bazhenov formation contain REY up to 0.014 ppb, while LREE is contained in 3.6 times more than HREE. An attempt to estimate the REY content in the pore water of the Bazhenov formation was made using water extract composition data.
2D reactive transport simulations of mid-ocean ridge hydrothermal systems
Authors: DePaolo Donald , Sonnenthal Eric , Pester Nicholas
Published: June 2019

Water-rock interactions in mid-ocean ridge hydrothermal systems are a critical part of Earth system evolution. Extensive insights have been developed from vent fluid chemistry and laboratory experiments, but these leave unanswered many questions about the temporal evolution and spatial structure of the hydrothermal systems that can only be addressed with reactive transport simulations. Other issues are the effects of changing spreading rates and seawater chemistry through Earth history. We are addressing this problem using the Toughreact code, starting with 2D static (no seafloor spreading) simulations of the near-axis region where most of the interaction occurs. The simulations use a dual-permeability grid to represent fractured rocks, and also have a formulation for Sr isotope exchange. Vent fluid Ca, Mg, SO4, and Na concentrations and Sr isotopes can be used as a guide to fluid chemical evolution. Initial simulations reproduce modern vent fluid chemistry even with maximum temperature only at 380°C, and suggest that fluids need not be in equilibrium with the rocks at any point in the system. Model fluids continue to evolve chemically even in the upflow zone prior to venting. The effects of different seawater chemical composition, as proposed for the Cretaceous, for example, can be captured with charge-balance models.
Layered Nb-REE ores in the Tomtor Complex (Arctic Siberia): Formation conditions
Authors: Lazareva Elena , Zhmodik Sergey , Dobretsov Nikolay , Tolstov Alexander , Karmanov Nikolay , Dar’in Andrey , Kirichenko Ivan
Published: June 2019

We study a unique deposit of Nb-REE ores that occur as three orebodies overlying weathered rocks of the Tomtor ultramafic alkaline-carbonatite complex in the northern Sakha Republic (Yakutia). The formation conditions of the rich Tomtor ores remain poorly constrained. Our hypothesis is that these ores, composed of detrital and authigenic minerals, were deposited in a hydrothermal lake. The Eh-pH parameters of water are reconstructed from REE distribution in ores and in monazite, with reference to results of thermodynamic calculations. The stability fields of hydrous Ce, La, and Nd phosphates in the Pourbaix diagrams are proximal in a region within a small range of pH (4-6) and Eh (-0.25 -+0.25 V). Monazite apparently formed by dehydration of the precursor phase of hydrous REE phosphate. This inference is supported by coexistence of Fe3+ and Fe2+ minerals.
Calcium and magnesium biogeochemistry in spruce catchments underlain by felsic, mafic, and ultramafic rocks
Authors: Krám Pavel , Oulehle Filip , Hruška Jakub , Veselovský František , Čuřík Jan , Myška Oldřich , Novák Martin , McDowell William H.
Published: June 2019

Three small forested catchments in the Czech Republic, each underlain by chemically contrasting silicate rocks, were investigated with focus on long-term atmospheric deposition of S, and pools and fluxes of Ca and Mg. Pools of Ca and Mg reflected geological substrate (granite: Ca, Mg poor, amphibolite: Ca, Mg rich, serpentinite: Ca poor, Mg rich). Long-term fluxes of S, Ca and Mg were tightly connected.
Increasing groundwater CO2 in a mid-continent tallgrass prairie: Controlling factors
Authors: Macpherson G.L. , Sullivan P.L. , Stotler R.L. , Norwood B.S.
Published: June 2019

Alkalinity and groundwater CO2 have increased linearly from 1991–2017 at the Konza Prairie Biological Station (KPBS), a tallgrass prairie research site in northeastern Kansas. The projected increase in groundwater alkalinity (as HCO3-) and CO2 based on an earlier trend was confirmed in 2016, with predictions nearly equal to recent values (e.g., 408 ppm vs 410 ppm as HCO3-, respectively). Both the water balance and groundwater CO2 trends within the study watershed could be impacted by long-term changes in land use and climate: 1) encroachment of woody vegetation (1983–2012) as a result of the 4-year fire return interval, 2) re-introduction of bison (phased in, 1994–2006), 3) increases in air temperature, and 4) changes in precipitation patterns. If only linear processes are driving the observed water chemistry changes, then the linear increase in air temperature (1983–2017) that stimulates soil respiration may be the most likely factor enhancing groundwater HCO3- and CO2, as air temperature has risen ~1 to 1.4°C over 34 years. If groundwater chemistry is driven by more threshold behaviour, woody encroachment, which was linear but in three distinct phases, may drive groundwater chemistry. The ~2 to 3‰ decrease in the discontinuous δ13C data in the groundwater-dominated stream suggests enhanced inputs of microbially-respired labile carbon, CO2 sourced from C3 (woody vegetation), or a combination of the two.
Effects of atmospheric CO2 consumption on rock weathering in the Pearl River basin, China
Authors: Qin Xiaoqun , Jiang Zhongcheng , Zhang Liankai , Huang Qibo , Liu Pengyu
Published: June 2019

Atmospheric CO2 is absorbed and dissolved in water via karst processes not only in carbonate rock areas, but in all rock areas of the earth. The chemical and isotopic analysis results, particularly of strontium, for water samples collected from eleven stations along the Pearl River, four times over the course of one year, showed that due to weathering by carbonate or silicate rocks, HCO3-, Ca2+, and Mg2+ have become the main ions in the river water. Through river ion stoichiometric and flux calculations, the carbonate rock weathering rate and atmospheric CO2 consumption were found to be 27.6 mm/ka and 540 x 103 mol/km2.a, which are 10.8 and 6.7 times the corresponding values for silicate rock. With the beneficial climatic conditions for rock erosion and large areas of carbonate rock in the Pearl River Basin, the atmospheric CO2 consumption value is about 2.6 times the average value for the 60 major rivers in the world.
Differences in hydrogeochemistry between shallow and deep aquifers in the Baiyangdian basin, China
Authors: Guo Huaming , Shen Zhaoli , Chen Yi , Zhao Kai , Li Haitao , Xiu Wei , Weng Lingbao
Published: June 2019

Groundwater is the dominant long-term water resource for agricultural irrigation and industrial production in the Baiyangdian basin, North China Plain. Groundwater and pore-water were investigated to evaluate chemical evolution and geochemical processes in shallow and deep aquifers. Results show that both shallow groundwater and shallow pore-water had higher TDS, Ca2+, Mg2+, SO42-, and HCO3- concentrations than deep groundwater and deep pore-water. Generally, concentrations of groundwater major ions were higher than those of pore-water in shallow aquifers, while they were slightly lower in groundwater than in pore-water from deep aquifers. Water isotopes showed the meteoric origin of groundwater and pore-water, although evaporation signature was traced in shallow groundwater. Shallow groundwater also experienced carbonate dissolution and silicate weathering. Silicate weathering and evaporite dissolution were the major hydrogeochemical processes in deep aquifers. This study indicated that deep groundwater has better water quality, but is vulnerable to contamination from shallow groundwater with high TDS and NO3- concentrations.
Hydrogeochemical survey of the Bagni di Lucca thermal zone with the purpose of monitoring hydrogeochemical foresights of earthquakes (Northern Tuscany, Italy)
Authors: Pierotti Lisa , Andreani Daniela , Botti Flavia , Chiellini Matteo
Published: June 2019

We present the results of a hydrogeochemical survey of the Bagni di Lucca area, a thermal district in the Serchio Valley, one of the areas of highest seismic risk in Tuscany, Italy. The aim of the survey was to identify a suitable site to be monitored for geochemical precursors of earthquakes. Based on hydrogeological and geochemical features, the Bernabò spring emerged as a proper candidate site for the installation and testing of an automatic monitoring station equipped with specific sensors for the continuous measurement of selected physical-chemical parameters (temperature, pH, electrical conductivity, redox potential).
O, H and C isotopic systematics of Icelandic groundwater
Authors: Sveinbjörnsdóttir Arny E. , Stefánsson Andri , Heinemeier Jan
Published: June 2019

Stable water isotopes of oxygen and hydrogen have been studied in Icelandic natural waters since 1960 for hydrological and geothermal research. All the waters are of meteoric and seawater origin. The measured range in δD and δ18O is large -131 to +3.3‰ and -20.8 to +2.3‰ respectively. Some of the waters are more depleted than any present-day precipitation suggesting a pre-Holocene component in the groundwater. Carbon isotopes of streams, rivers, soil and groundwater have been studied since 1990 in order to evaluate the carbon sources and reactions that possibly influence the carbon systematics of the water. Results show large range of values, for δ13CDIC -27.4 to +4.5‰ and for 14CDIC +0.6 to +118 pMC. Apart from atmospheric, organic and rock leaching, input of gas at depth with similar isotopic composition as the pre-erupted melt of the upper mantle and lower crust beneath Iceland have been identified as sources for carbon in the deeper groundwater.
Fluid-induced metamorphism and anatexis of refractory Ni-Co-Cu sulphides in subduction-related rocks
Authors: Kepezhinskas Nikita
Published: June 2019

The role of metamorphism on refractory sulfides is not well constrained. Although experiments have displayed the effectiveness of high grade metamorphism, namely granulite facies metamorphism, on sulfide anatexis, its role in the presence of other variables is still poorly understood. Rocks from the Bay Islands Accretionary Complex in Honduras and the Ildeus-Lucha Complex in Russia exhibit extensive metamorphism. Sulfide mineralization is prolific in these rocks suggesting that metamorphism has played an important role in re-concentrating these sulfides during amphibolite and granulite facies metamorphism.
Gold, platinum and palladium enrichments in arcs: role of mantle wedge, arc crust and halogen-rich slab fluids
Authors: Kepezhinskas Pavel , Kepezhinskas Nikita , Berdnikov Nikolai
Published: June 2019

Arc-related magmas are frequently enriched in Au, Pt and Pd in respect to MORB and OIB igneous suites. Magmatic arcs commonly host large-scale hydrothermal Au and Au-Cu and PGE mineralization related to young volcanic systems and zoned ultramafic complexes respectively. Island-arc mantle xenoliths show Au, Pt, Pd enrichments related to mantle wedge metasomatism by slab-derived fluids. Long-lived plumbing systems in arc crust (arc magma chambers) show further enhancement of Au, Pt and Pd enrichments through subduction-related metamorphic and metasomatic processes in the presence of halogen-rich, aqueous fluids. We propose that Au-Pt-Pd enrichments in arcs are caused by mantle wedge-slab interactions followed by differentiation and metamorphism of magmatic conduits in arc crust.
Geochemical indicators of paleo-seismicity based on the data of study of Fumarolnoe lake bottom sediments (Kamchatka, Uzon)
Authors: Kirichenko Ivan , Dobretsov Nikolay , Zhmodik Sergey , Lazareva Elena , Belyanin Dmitry
Published: June 2019

The distribution of chemical elements in bottom sediments of Fumarolnoe lake was obtained by XRFA. The mineral composition of the sediment was examined by SEM, XPA. Variations in contents of alkaline elements in the column of bottom sediments of the Fumarolnoe Lake have been studied using spectral methods (Wavelet and Fourier analyses). It has been established that concentrations of these elements change periodically, periods being correlated with periodic changes in seismic conditions of the present region
Strategies to suppress internal loads of metals in sediments
Authors: Hansen Anne M.
Published: June 2019

Sediments may act as secondary sources of pollutants, but no known criteria establish such relationship. This study aims at evaluating internal loads of Ni from sediments due to changing redox conditions caused by application of water treatment such as hypolimnetic oxygenation. Through hydrogeochemical modelling and experimental evaluation, the distribution of Ni was evaluated. Sediment and water samples from a reservoir located in central Mexico were located in a reactor and Eh was controlled in ±50 mV steps between +300 and -450 mV. The release of Ni was evaluated in each step and the results were construed to the reservoir, considering that water-sediment interaction occurs in a 5-cm sediment layer with known density. Under oxidized conditions, the metal was accumulated in the sediment. With the dissolution of Fe at lower Eh, dissolved concentrations of Ni increased. Under even lower Eh conditions, these concentrations decreased again. This was related to the formation of iron sulphide. Combining experimental evaluation with hydrogeochemical modelling, allowed evaluating different scenarios of distribution of Ni. The knowledge of reductive dissolution of metals is therefore essential for decision-making to mitigate health effects as result of water treatment strategies.
Thorium and Uranium distribution in a passive system for mine water treatment
Authors: Prudêncio Maria Isabel , Valente Teresa , Marques Rosa , Sequeira Braga Maria Amália , Pamplona Jorge
Published: June 2019

The abandoned Jales mining area is a sulphide-rich deposit (Northeast of Portugal). Acid mine drainage resulted from oxidation of sulphides is treated in a passive system with wetlands. The present work studies the thorium and uranium behaviour in the water and in the fine fractions of wetland soils throughout the passive treatment system. The evaluation of the efficiency of the all system was done determining metals concentration variation in the creek water upstream and downstream of the treated effluent discharge. The results point to higher efficiency to retain Th after summer than after winter. The opposite was found for uranium, which increases significantly in the creek water after summer and, in a lower extent, after winter. Also, Th and U have a tendency to increase in the fine fractions of the wetlands soils after summer, which can be explained by the longer water-soil contact/lower water dynamics. Nevertheless uranium has a much higher tendency to be in solution as revealed by a high concentration in the porewater of wetland soils. A relation of these actinides behaviour with the Fe and Mn distribution is not clear.
Hydrogeological conditions of potable water supply the Kuznetsk Coal Basin, Russia
Authors: Purgina Darya , Kuzevanov Konstantin , Burmаkovа Elena
Published: June 2019

The article deals with hydrogeological conditions of the groundwater resources in the western part of the Kuznetsk depression, a coal and ore mining region. On the basis of a scheme of hydrogeological boundary conditions, a numerical geologic filtration model is developed for calculation of groundwater resources in the study area. The hydrologic budget of the numerical model is evaluated for assessment of infiltration recharge of groundwater resources.
Characterization study of As and Se in pyrites from two historic mines in British Columbia
Authors: Ross-Lindeman Jocelyn , Kirste Dirk
Published: June 2019

Arsenic (As) and selenium (Se) can be toxic if they occur as soluble species at elevated concentrations. One process that can mobilize these elements into the environment is the oxidation of As- and Se-containing pyrites. This study presents the initial mineralogical (XRD, SEM-EDS, LA-ICP-MS, and synchrotron micro-XRF and micro-XANES) characterization of As- and Se-pyrites from two historic mines in British Columbia, the Sullivan Mine and the Sunro Mine. Results show that As occurs in some of the pyrites from the Sullivan Mine; comparison of the micro-XANES measurements to published data suggests As substitutes for sulphur. Selenium is detected in pyrites from the Sunro Mine but this Se is slightly more oxidized than measured in previous studies on Se-pyrite and further investigation of these samples is required. Results from this characterization study will be incorporated into the next phase of research measuring element mobilization after oxidation reactions to identify the effects of As or Se substitution on these reactions.
Hydrochemical Characteristics of High-fluorine Groundwater in the Plain of the Yarkant River Basin, Northwest China
Authors: Zhang Jie , Zhou Jinlong , Zhou Yinzhu , Zeng Yanyan , Chen Yunfei
Published: June 2019

Study on regional distribution of high-fluorine groundwater will help to understand migration and transformation of fluorine, and provide the theoretical basis of low-fluorine groundwater exploration in high-fluorine groundwater areas. In this study, 74 shallow groundwater samples collected from plain area of the Yarkant River Basin in Xinjiang were analyzed. Results showed that the type I (low-fluorine groundwater, F-<1mg/L) was distributed in the piedmont plain, the type II (high-fluorine groundwater, 1mg/L≤F-<2mg/L) was distributed in the central and northeastern part of the basin, and the type III (high-fluorine groundwater F-≥2mg/L) was continuously distributed along the flow direction of river water in the western part of the basin. The average concentration of groundwater fluorine was 1.26 mg/L, with an exceeding standard rate of 48.65%. Groundwater cations were dominated by Ca2+ and Mg2+ and anions were dominated by SO42- and Cl-. High-fluorine groundwater occurred under neutral to weak alkaline environment with pH ranged between 6.61 and 7.99, which is favorable for the dissolution of fluorine-bearing minerals. Average concentration of total dissolved solids (TDS) in type I, type II and type III groundwater were 1657 mg/L, 3522 mg/L and 3724 mg/L, respectively. High-fluoride groundwater generally had high TDS concentrations.
LFER and the Effect of Temperature on Oxyanion Adsorption by Goethite
Authors: Dabizha Anna , Vlasova Nataliya , Kersten Michael
Published: June 2019

A linear relationship between the Gibbs free energy, ΔGr,H+, of the aqueous complex deprotonation reaction, and the Gibbs free energy, ΔGr,ads, of bidentate surface complexation reaction of oxyanions was derived from modelling of temperature dependent batch equilibrium adsorption experiments. As exemplified in this study, this relationship may be exploited to predict temperature-dependent adsorption behavior of oxyanions not yet known such as pertechnetate.
Hydraulic conductivity of peat in Western Siberia
Authors: Kramarenko Violetta , Brakorenko Natalya , Molokov Viktor
Published: June 2019

The paper aims at estimating hydraulic conductivity of peat. It is a complicated process since peat has some unique properties that are not typical for mineral soils. Other difficulties involve the lack of elaborated procedure for laboratory testing and data processing, high sensitivity of peat soils to external and internal factors; which leads to considerable fluctuation in peat hydraulic conductivity values. The specific properties of hydraulic conductivity in peat soils are proved by numerous experimental data. The article also provides the permeability values for the most typical peat species in Western Siberia. The obtained data allow forecasting peat soil response to the development of peatlands.
Tracing surface and ground water with stable isotopes in a small permafrost research catchment
Authors: Lebedeva Liudmila
Published: June 2019

The study aims at assessing groundwater contribution to the streamflow at the small permafrost Shestakovka river watershed in Central Yakutia. Water from stream, lakes, snow, rain, surface flow and suprapermafrost groundwater is characterized by specific isotopic signature. At least one third of the spring flood is formed by “old” pre-event water as showed by mixing model based on stable isotopes as tracers. Presence of talik aquifers associated with sandy hills covered by pine forest suggests that talik groundwater could be an important source of streamflow at the small river basin in continuous permafrost.
The study of the interactions between Sava River and Zagreb aquifer system (Croatia) using water stable isotopes
Authors: Parlov Jelena , Kovač Zoran , Barešić Jadranka
Published: June 2019

Water stable isotopes were used to investigate hydrological pathways and interactions between surface water and groundwater in the Zagreb aquifer system (Croatia). δ2H and δ18O values indicate a spatial variability of the influence of individual groundwater sources inside the aquifer – local precipitation and the Sava River water. Fractions of surface water in groundwater strongly depend on fluctuations of the river water level and less on the distance from the Sava River. These data extend our understanding of groundwater flow in the Zagreb aquifer system, interactions between Sava River water, local precipitation and groundwater. The results of the research allow more precise monitoring plans and definition of the sanitary protection zones of the well fields in the future.
Application of Multi-Tracer Methods to Evaluate Nitrate Sources and Transformation in Sabkha Matti (Saudi Arabia)
Authors: Saeed Waleed , Shouakar-Stash Orfan , Unger Andrè , Wood Warren W.
Published: June 2019

An unusually high concentration of nitrate (NO3) ranging between 291 and 6790 mg/L (as N) was observed during a review of solute data for brine samples from the inland Sabkha Matti. A multi-tracer approach considering water chemistry, stable nitrate isotopes (δ15N and δ18O), and the radioactive isotope of hydrogen (tritium, 3H) was utilized to evaluate the nitrate sources and transformation in this hydrogeological setting. The results suggested that the source of the high nitrate levels is related to a leakage from a manure/septic system near the proximal eastern edge of the Sabkha. Moreover, the impact of Sabkha’s characteristics on biological denitrifications was evaluated in this study. The results suggest that denitrification was not a major process in Sabkha Matti. Several factors may contribute to the limitation of denitrification on the brine samples including high dissolved oxygen contents, high salinity and chloride.
The carbon isotopes ratio in small lakes bottom sediments located in the forest-steppe and steppe zones of southern Siberia
Authors: Strakhovenko Vera , Ovdina Ekaterina , Malov Georgy
Published: June 2019

Isotopic variations of carbon of the carbonates and organic matter in bottom sediments of lakes of two lake systems located in the South of Siberia are studied: Baraba (Baraba steppes) and Tazheran (Tazheran steppes). Isotopic studies of δ13C carbonates and organic matter of the lacustrine bottom sediments of the Tazheran and Baraba systems indicate two main mechanisms of authigenic carbonates formation: chemogenic deposition and biochemogenic deposition due to bacterial destruction of organic matter. The dependence of the δ13Corg and δ13Ccarb, the degree of water salinity is not revealed. Forms by chemogenic carbonates are similar to water isotopic values, i.e. with dissolved bicarbonate - ion reservoir. However, in most of the studied lakes the light isotopic composition δ13Ccarb was revealed, as carbonates are formed in the environment with a high content of isotope-light CO2 formed by the oxidation of carbon dioxide emitted by bacteria-decomposers in the mineralization process of the original organic matter in the stagnant waters in the anaerobic environment.
A 20-year record of water chemistry in an alpine setting, Mount Emmons, Colorado, USA
Authors: Wanty Richard B. , Manning Andrew H. , Johnson Michaela R. , Verplanck Philip L.
Published: June 2019

From 1997 to the present, the U.S. Geological Survey and other agencies have been collecting water samples for chemical analyses on Mount Emmons in central Colorado, USA. The geology of Mount Emmons is dominated by Upper Cretaceous to Paleogene sediments of marine to continental origin, with felsic intrusive rocks interrupting the sedimentary block. Extensive sulphide-rich alteration accompanied the intrusive events and forms an alteration halo in the sediments. Weathering of these sulphide minerals has led to numerous springs and seeps with a naturally low pH and high concentrations of metals, especially Fe and Zn. Superimposed on the natural geochemical signature are acid, metal-rich drainages from several mines and drill holes. Thus, streams on Mt. Emmons have a mix of natural and anthropogenic metal sources. Nearly 450 samples compose the database, with numerous sample locations replicated from the late 1990s to the present. Although there does not appear to be any temporal pattern in the data, consistent spatial variations are observed that allow us to characterize the natural and anthropogenic water sources.
IBA analysis of modern pigments and papers: new data on color alteration and limits for safe analysis
Authors: Zucchiatti A. , Martina S.
Published: June 2019

The response of modern, commercial drawing and painting media and papers to proton irradiation has been studied in a set of 180 colour/paper combinations aimed at assessing the potential of PIXE for the characterization of modern artistic materials. In the marks that appeared on some of the materials, during and after irradiation, colour changes have been calculated and used to set the beam current and the fluence limits for safe analysis.
Selective photothermolysis of spider veins and reticular varices with the long-pulsed Nd:YAG laser
Authors: Fratila A. A. M. , Gauglitz G. G. , Strohbücker A. , Radu D.
Published: June 2019

The therapy of spider veins, telangiectasia and reticular veins of lower extremities can be successfully performed with sclerotherapy or by using the long pulsed (LP) Nd:YAG laser. A matter of discussion, however, is how should laser parameters – such as wavelength, fluence, pulse duration, number of pulses – be utilized for effective and selective photothermolysis treatment without any side effects. The selective photothermolysis was introduced in 1983 by Anderson and Parrish 1 as a concept in laser treatment, meaning the selective thermal destruction of the target tissue (the chromophores – the light-absorption molecule is here the blood vessel) using a specific laser light wavelength, with minimal injury to surrounding tissue (the skin). The effectiveness of the selective photothermolysis process using an LP Nd:YAG laser at 1064 nm for the treatment of leg veins telangiectasias up to 2 mm in diameter, is the result of 30-years clinical experience sustained by patient satisfaction and photo documentation. The use of double and triple pulses seems to be the key of success in treating even larger vessels and has demonstrated superior safety and efficacy. Even bigger telangiectasias, reticular veins or other dilated veins on neckline, upper abdomen or in the face can be successfully treated with the LP Nd:YAG laser.