Strontium isotopic composition as tracer of weathering processes, a review with respect to James Ross Island, Antarctica

2012 ◽  
Vol 2 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Jitka Míková
Keyword(s):  
Natural Environments ◽  
Polar Regions ◽  
Sr Isotopes ◽  
Mixing Processes ◽  
Rock Interaction ◽  
Weathering Rates ◽  
Weathering Processes ◽  
James Ross Island ◽  
Flow Pathways ◽  
Geochemical Studies

Strontium isotopes (87Sr/86Sr) are routinely used to determine sources and mixing relationships in geochemical studies. They have proven to be useful in determining weathering processes and quantifying end-member mixing processes. A number of studies highlight that Sr isotopes represent a powerful tool helping to constrain weathering reactions, weathering rates, flow pathways and mixing scenarios, even when inherent differences in weathering rates of different minerals, and mineral heterogeneity in natural environments may cause difficulties in defining the weathering component of different geochemical systems. Nevertheless, Sr isotopes are useful when combined with other chemical data, to constrain models of water–rock interaction and mixing as well as geochemical processes such as weathering. This paper presents basic information about Sr isotopic system, new analytical developments, summary of recent published studies in constraining the weathering processes, and indicates studies similar to weathering in polar regions. The aim of this paper is to present rationale of using Sr isotopes as tracer of weathering processes on James Ross Island, Antarctica.

scholarly journals Waters from the Djiboutian Afar: A Review of Strontium Isotopic Composition and a Comparison with Ethiopian Waters and Red Sea Brines

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1700 ◽  
Author(s):  
Tiziano Boschetti ◽  
Mohamed Awaleh ◽  
Maurizio Barbieri
Keyword(s):  
Red Sea ◽  
Hot Springs ◽  
Ethiopian Rift ◽  
Concentration Data ◽  
Mixing Processes ◽  
Main Ethiopian Rift ◽  
Weathering Processes ◽  
Sea Bottom ◽  
Geochemical Studies ◽  
Freshwater Aquifers

Drinking water is scarce in Djibouti because of the hot desert climate. Moreover, seawater intrusion or fossil saltwater contamination of the limited number of freshwater aquifers due to groundwater overexploitation affect those who live close to the coastline (~80% of the population). Despite this, the geothermal potential of the country’s plentiful hot springs could resolve the increasing electricity demand. Strontium isotopes (87Sr/86Sr) are routinely used to determine sources and mixing relationships in geochemical studies. They have proven to be useful in determining weathering processes and quantifying endmember mixing processes. In this study, we summarise and reinterpret the 87Sr/86Sr ratio and Sr concentration data of the groundwater collected to date in the different regions of the Djibouti country, trying to discriminate between the different water sources, to evaluate the water/rock ratio and to compare the data with those coming from the groundwater in the neighbouring Main Ethiopian Rift and the Red Sea bottom brine. New preliminary data from the groundwater of the Hanlé-Gaggadé plains are also presented.

Use of Sr isotopes as a tool to decipher the soil weathering processes in a tropical river catchment, southwestern India

2015 ◽  
Vol 63 ◽  
pp. 498-506 ◽  
Author(s):  
G.P. Gurumurthy ◽  
K. Balakrishna ◽  
M. Tripti ◽  
Jean Riotte ◽  
Stéphane Audry ◽  
...  
Keyword(s):  
Sr Isotopes ◽  
Tropical River ◽  
River Catchment ◽  
Soil Weathering ◽  
Weathering Processes ◽  
Southwestern India

scholarly journals Novel Applications of Nanoparticles in Nature and Building Materials

2021 ◽  
Author(s):  
Juyoung Ha
Keyword(s):  
Chemical Weathering ◽  
Building Materials ◽  
Mine Drainage ◽  
Bulk Material ◽  
Chemical Properties ◽  
Future Research ◽  
Natural Environments ◽  
Weathering Processes ◽  
Different Types ◽  
Novel Applications

Nanoparticles are assemblies of atoms in the size range less than 100 nanometers. At these length scales, the properties of particles may deviate significantly from those of the equivalent bulk material indicating that changes in physical and chemical properties of materials depend on the dimensions of the particle. The presence of mineral nanoparticles has been reported in a range of natural environments. Such nanoparticles can arise from a variety of mechanisms, including chemical weathering processes, precipitation from relatively saturated solutions in hydothermal and acid mine drainage environments, evaporation of aqueous solutions in soils, and biological formation by a variety of different microorganisms. Furthermore, recent increased applications of nanoparticles in different types of industries, including construction and building material manufacturing, have caused prevalent occurrences of different types of synthetic nanoparticles in the environment. In this chapter, a comprehensive reviews on occurrences and observations of naturally and anthropogeniccally generated nanoparticles in the environment and their characterization techniques will be discussed along with directions and suggestions for the future research topics and areas for nanomaterials.

scholarly journals Physical processes behind interactions of microplastic particles with natural ice

2022 ◽  
Author(s):  
Irina P Chubarenko
Keyword(s):  
Sea Ice ◽  
Ice Core ◽  
Ice Cores ◽  
Natural Environments ◽  
Polar Regions ◽  
Air Bubbles ◽  
Field Observations ◽  
Physical Processes ◽  
Ice Surface ◽  
Brittle Ductile Transition

Abstract Microplastic particles (MPs, <5 mm) are found in marine ice in larger quantities than in seawater, however, the distribution pattern within the ice cores is not consistent. To get insights into the most general physical processes behind interactions of ice and plastic particles in cool natural environments, information from academic and applied research is integrated and verified against available field observations. Non-polar molecules of common-market plastics are hydrophobic, so MPs are weak ice nucleators, are repelled from water and ice, and concentrate within air bubbles and brine channels. A large difference in thermal properties of ice and plastics favours concentration of MPs at the ice surface during freeze/thaw cycles. Under low environmental temperatures, falling in polar regions below the glass / brittle-ductile transition temperatures of the common-use plastics, they become brittle. This might partially explain the absence of floating macroplastics in polar waters. Freshwater freezes at the temperature well below that of its maximum density, so the water column is stably stratified, and MPs eventually concentrate at the ice surface and in air bubbles. In contrast, below growing sea ice, mechanisms of suspension freezing under conditions of (thermal plus haline) convection should permanently entangle MPs into ice. During further sea ice growth and aging, MPs are repelled from water and ice into air bubbles, brine channels, and to the upper/lower boundaries of the ice column. Sea ice permeability, especially while melting periods, can re-distribute sub-millimeter MPs through the brine channels, thus potentially introducing the variability of contamination with time. In accord with field observations, analysis reveals several competing factors that influence the distribution of MPs in sea ice. A thorough sampling of the upper ice surface, prevention of brine leakage while sampling and handling, considering the ice structure while segmenting the ice core – these steps may be advantageous for further understanding the pattern of plastic contamination in natural ice.

scholarly journals Decoupling silicate weathering from primary productivity – how ecosystems regulate nutrient uptake along a climate and vegetation gradient

2020 ◽  
Author(s):  
Ralf A. Oeser ◽  
Friedhelm von Blanckenburg
Keyword(s):  
Nutrient Uptake ◽  
Nutrient Recycling ◽  
Fold Increase ◽  
Mineral Nutrient ◽  
Simultaneous Increase ◽  
Vegetation Growth ◽  
Weathering Rates ◽  
Weathering Processes ◽  
Below Ground ◽  
Gains And Losses

Abstract. In addition to the supply of primary minerals and water flow the presence and growth of land plants are thought to drive rock weathering. While doubtlessly plants and their associated below-ground microbiota possess the tools for considerable weathering work, the quantitative evaluation of their impact relative to the common abiogenic weathering processes remains poorly known. Here we report on a strategy to decipher the relative impact of these two drivers. We did so by quantifying weathering rates and nutrient uptake along the EarthShape transect in the Chilean Coastal Cordillera where landscapes are subjected to a substantial north to south gradient in precipitation and vegetation growth, whereas rock type is granitoid throughout and tectonic process rates do not differ much along the gradient. We quantified the bio-available fraction of nutritive elements in regolith and we measured 87Sr/86Sr isotope ratios in the different compartments of the Earth’s Critical Zone (bedrock, regolith, bio-available fraction in saprolite and soil, and vegetation) to identify the sources of mineral nutrients to plants. We thereby budgeted inventories, gains, and losses of nutritive elements in and out of these ecosystems, and quantified mineral nutrient recycling. We found that the weathering rates do not increase with precipitation from north to south along the climate gradient. Instead, the simultaneous increase in biomass growth rate is accommodated by faster nutrient recycling. The absence of an increase in weathering rate in spite of a five-fold increase in precipitation leads us to hypothesize that the presence of plants can negatively impact weathering through inducing secondary-mineral formation and by fostering a microbial community that is adapted for nutrient-recycling rather than nutrient-acquisition through weathering.

scholarly journals U-Pb zircon and titanite ages and Sr-Nd-Hf isotope constraints on the timing and evolution of the Petrohan-Mezdreya pluton (Western Balkan Mts, Bulgaria)

2018 ◽  
Vol 47 (2) ◽  
pp. 25-46
Author(s):  
Irena Peytcheva ◽  
Elena Tacheva ◽  
Albrecht von Quadt ◽  
Rossen Nedialkov
Keyword(s):  
Early Carboniferous ◽  
Variscan Orogeny ◽  
Magma Evolution ◽  
Mixing Processes ◽  
Icp Ms ◽  
Younger Age ◽  
Incremental Growth ◽  
Combination Of Methods ◽  
Geochemical Studies

A combination of methods is applied in the present study to define the exact age of the Petrohan and Mezdreya plutons and trace their magma evolution. Field, petrological, and geochemical studies of the Petrohan pluton revealed its complex evolution and emphasized the role of magma mingling and mixing, complementary to the normal assimilation and fractional crystallization (AFC) processes. Using high-precision conventional U-Pb (CA)-ID-TIMS zircon and titanite dating in combination with CA-LA-ICP-MS zircon dating and tracing, we suggest an incremental growth of a common Petrohan-Mezdreya pluton. It was assembled over minimum 4.5 Ma from 311.14±0.48 Ma to 307.54±0.54 Ma. The younger age of the gabbro (308.12±0.33 Ma), compared with the age of granodiorites (311.14±0.48 Ma), provides numerical proofs for magma replenishment during the assembling of the Petrohan pluton. Whole-rock strontium-neodymium (initial 87Sr/86Sr ratios of 0.70521–0.70527 to 0.70462 and 143Nd/144Nd of 0.51221 to 0.51210) and Hf-zircon isotope data (ε-Hf from –5.8 to +3.6) argue for interaction of mantle derived magma with crustal melts but also mixing and mingling and transfer of zircon grains between the gabbroic and granitic melts. Possible petrogenetic scenario includes melting of subcontinental mantle lithosphere and crust and evolution trough AFC, FC and mingling/mixing processes. Considering the Petrohan-Mezdreya pluton as part of the Variscan orogeny in SE Europe, our new data support the accretion/collision of both the Balkan and Sredna Gora/Getic units with Moesia in the Early Carboniferous followed by syn- and post-collisional Carboniferous and Permian magmatism.

Unravelling the hidden evidences of magma mixing processes via combination of in situ Sr isotopes and trace elements analyses on plagioclase crystals

Lithos ◽  
2021 ◽  
pp. 106435
Author(s):  
Adriana Alves ◽  
Valdecir de Assis Janasi ◽  
Giovanna de Souza Pereira ◽  
Fernando Araújo Prado ◽  
Patricio R.M. Munoz
Keyword(s):  
Trace Elements ◽  
Magma Mixing ◽  
Sr Isotopes ◽  
Mixing Processes

Coupling geochemical and isotopic tracers (δ18O, δ2H and 87Sr/86Sr) to quantify groundwater mixing in carbonate environment

2021 ◽  
Author(s):  
Thibaut Garin ◽  
Bernard Ladouche ◽  
Bruno Arfib ◽  
Benoit Dewandel ◽  
Julio Goncalves
Keyword(s):  
Quantitative Estimation ◽  
Groundwater Resources ◽  
Mixing Processes ◽  
Isotopic Tracers ◽  
Dye Tracing ◽  
Rock Interaction ◽  
Marine Influence ◽  
End Members ◽  
Different Origins

&lt;p&gt;Carbonate aquifers are known as a major source for drinking water in the Mediterranean region. Therefore, qualitative and quantitative estimation of the groundwater resource are crucial, especially in area with densely populated areas.&lt;/p&gt;&lt;p&gt;In this study, geochemical and isotopic tracers (&amp;#948;&lt;sup&gt;18&lt;/sup&gt;O, &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H and &lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr) have been used to discriminate different origins of groundwater and evaluate water-mass mixing in a Mediterranean carbonate environment. The case study, located in south-eastern France, offers an attractive geological context to explore strontium isotopic tracers: trias to cretaceous carbonate rocks, that have been eroded and locally resedimented in fluvial deposits during Oligocene extension and Quaternary periods. Moreover, many karst features act as sinking zones, generating fast infiltration. The 500 km&amp;#178; zone investigated has also a large range of elevation, from the sea to 1148m, giving an expected significant contrast in water isotopes. Monthly water samples have been collected in-situ for two years on ground and surface waters, in rivers, boreholes as well as karstic springs. Monthly rainwater samples provide the isotopic signal of the recharge at two distinct elevations and distance from the sea.&lt;/p&gt;&lt;p&gt;The hydrogeochemical signatures allow to discriminate the end-members of two main waterbodies as well as a slight marine influence on one borehole. Nitrates concentrations (NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;) highlight anthropogenic influence on groundwater resources. A multi-tracer approach taking in account water-rock interaction, mixing processes and recharge, coupled with hydrogeological conditions and dye-tracing tests, leads to a conceptual model of this complex hydrosystem.&lt;/p&gt;

Characterization of groundwater composition in Punjab state with special emphasis on uranium content, speciation and mobility

2014 ◽  
Vol 102 (3) ◽  
pp. 239-254
Author(s):  
Ajay Kumar ◽  
R. M. Tripathi ◽  
Sabyasachi Rout ◽  
Manish K. Mishra ◽  
P. M. Ravi ◽  
...  
Keyword(s):  
Uranium Content ◽  
Activity Levels ◽  
Secular Equilibrium ◽  
Deep Aquifer ◽  
Rock Interaction ◽  
Aquifer System ◽  
Weathering Processes ◽  
Ionic Concentrations ◽  
Parent Rocks ◽  
Order Of Magnitude

Abstract Groundwaters (borewell and handpump) were sampled from two districts (Bathinda and Mansa) of Punjab state and analyzed for their major ionic concentrations and uranium isotope compositions in order to assess the possible origins of the waters and water–rock interactions that occurred in the deep aquifer system. The major ionic concentrations of waters were plotted on a Piper diagram and grouped into four dominant hydrochemical facies as (Na+K)-SO4+Cl type (69% – 73%), (Ca+Mg)-SO4+Cl type (6% – 21%), (Ca+Mg)–HCO3 type (4% – 6%) and (Na+K)-HCO3 type (2% – 19%). It was observed that mobility of uranium in groundwater was very much influenced by TDS (total dissolved solids). To investigate the various mechanisms for deriving the elevated uranium concentrations in groundwater, 234U/238U activity ratios (ARs) were calculated using the determined activity levels of 234U and 238U. The mean ARs was found to be near unity (i.e. secular equilibrium) in the study regions confirmed that uranium in groundwaters was mainly resulted from its host/parent rocks through weathering processes. The concentration of HCO3 − in ground water showed one order of magnitude higher than the total dissolved SiO2 indicates that carbonate weathering was the dominant process due to major water–rock interaction. The uranium speciation in groundwaters was investigated by an equilibrium model calculation using MEDUSA (make equilibrium diagrams using sophisticated algorithms) under the influence of redox conditions and complexant concentration. At the observed range of pH values, the predominant redox speciation of uranium was observed as hydroxo-carbonato complexes of (UO2)2(CO3)(OH)3 − and hydroxyl complexes of UO2(OH)3 − which might be caused for increasing the solubility of uranium. Due to very low concentration of phosphate in groundwater, its effects on U(VI)-aqueous speciation was negligible.

Sign in / Sign up

Export Citation Format

Share Document