Chromium Stable Isotope Panorama of Chondrites and Implications for Earth Early Accretion

2021 ◽  
Vol 923 (1) ◽  
pp. 94
Author(s):  
Ke Zhu ◽  
Frédéric Moynier ◽  
Conel M. O’D. Alexander ◽  
Jemma Davidson ◽  
Devin L. Schrader ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Isotope Composition ◽  
Acid Leaching ◽  
Building Blocks ◽  
Silicon Isotope ◽  
Stable Isotope Fractionation ◽  
Two Samples ◽  
Enstatite Chondrite ◽  
Enstatite Chondrites

Abstract We investigated the stable isotope fractionation of chromium (Cr) for a panorama of chondrites, including EH and EL enstatite chondrites and their chondrules and different phases (by acid leaching). We observed that chondrites have heterogeneous δ 53Cr values (per mil deviation of the 53Cr/52Cr from the NIST SRM 979 standard), which we suggest reflect different physical conditions in the different chondrite accretion regions. Chondrules from a primitive EH3 chondrite (SAH 97096) possess isotopically heavier Cr relative to their host bulk chondrite, which may be caused by Cr evaporation in a reduced chondrule-forming region of the protoplanetary disk. Enstatite chondrites show a range of bulk δ 53Cr values that likely result from variable mixing of isotopically different sulfide-silicate-metal phases. The bulk silicate Earth (δ 53Cr = –0.12 ± 0.02‰, 2SE) has a lighter Cr stable isotope composition compared to the average δ 53Cr value of enstatite chondrites (–0.05 ± 0.02‰, 2SE, when two samples out of 19 are excluded). If the bulk Earth originally had a Cr isotopic composition that was similar to the average enstatite chondrites, this Cr isotope difference may be caused by evaporation under equilibrium conditions from magma oceans on Earth or its planetesimal building blocks, as previously suggested to explain the magnesium and silicon isotope differences between Earth and enstatite chondrites. Alternatively, chemical differences between Earth and enstatite chondrite can result from thermal processes in the solar nebula and the enstatite chondrite-Earth, which would also have changed the Cr isotopic composition of Earth and enstatite chondrite parent body precursors.

scholarly journals Technical Note: Silica stable isotopes and silicification in a carnivorous sponge \\textit{Asbestopluma} sp.

2014 ◽  
Vol 11 (12) ◽  
pp. 16573-16597
Author(s):  
K. R. Hendry ◽  
G. E. A. Swann ◽  
M. J. Leng ◽  
H. J. Sloane ◽  
C. Goodwin ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Oxygen Isotope ◽  
Isotope Composition ◽  
Isotopic Signature ◽  
The Body ◽  
Oxygen Isotope Composition ◽  
Silicon Isotope ◽  
Deep Seawater ◽  
Differential Distribution ◽  
Sponge Spicule

Abstract. The stable isotope composition of benthic sponge spicule silica is a potential source of palaeoceanographic information about past deep seawater chemistry. The silicon isotopic composition of spicules has been shown to relate to the silicic acid concentration of ambient water, although existing calibrations do exhibit a degree of scatter in the relationship. Less is known about how the oxygen isotope composition of sponge spicule silica relates to environmental conditions during growth. Here, we investigate the biological vital effects on silica silicon and oxygen isotope composition in a carnivorous sponge, Asbestopluma sp., from the Southern Ocean. We find significant variations in silicon and oxygen isotopic composition within the specimen that appear related to unusual spicule silicification. The largest variation in both isotope systems was associated to the differential distribution of an unconventional, hypersilicified spicule type (desma) along the sponge body. The absence of an internal canal in the desmas suggests an unconventional silicification pattern leading to an unusually heavy isotopic signature. Additional internal variability derives from a systematic offset between the peripheral skeleton of the body having systematically a higher isotopic composition than the internal skeleton. A simplified silicon isotope fractionation model, in which desmas were excluded, suggests that the lack of a system for seawater pumping in carnivorous sponges favours a low replenishment of dissolved silicon within the internal tissues, causing kinetic fractionation during silicification that impacts the isotopic signature of the internal skeleton. Analysis of multiple spicules should be carried out to "average out" any artefacts in order to produce more robust downcore measurements.

scholarly journals Measurement report: Spatial variability of northern Iberian rainfall stable isotope values – investigating atmospheric controls on daily and monthly timescales

2021 ◽  
Vol 21 (13) ◽  
pp. 10159-10177
Author(s):  
Ana Moreno ◽  
Miguel Iglesias ◽  
Cesar Azorin-Molina ◽  
Carlos Pérez-Mejías ◽  
Miguel Bartolomé ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Air Temperature ◽  
Isotope Composition ◽  
Significant Negative Correlation ◽  
Relative Role ◽  
Northern Spain ◽  
Mass Source ◽  
Highly Correlated

Abstract. For the first time, this article presents a large dataset of precipitation isotopic measurements (δ18Op and δ2Hp) sampled every day or 2 d from seven sites on a west-to-east transect across northern Spain for 2010–2017. The main aim of this study is to (1) characterize the rainfall isotopic variability in northern Spain at daily and monthly timescales and (2) assess the principal factors influencing rainfall isotopic variability. The relative role of air temperature and rainfall in determining the stable isotope composition of precipitation changes along the west-to-east transect, with air temperature being highly correlated with δ18Op at daily and monthly timescales, while a few sites along the transect show a significant negative correlation with precipitation. The highest air temperature–δ18Op dependency is found for a station located in the Pyrenees. Frontal systems associated with North Atlantic cyclones are the dominant mechanism inducing precipitation in this region, particularly in winter. This study allows an exploration of the role of air mass source and trajectory in determining the isotopic composition of rainfall in northern Iberia by characterizing the moisture uptake for three of the seven stations. The importance of continental versus marine moisture sources is evident, with clear seasonal and spatial variations. In addition, the type of precipitation (convective versus frontal rainfall) plays a key role, with convective rainfall associated with higher δ18Op values. This comprehensive spatiotemporal approach to analyzing the rainfall isotopic composition represents another step forward towards developing a more detailed, mechanistic framework for interpreting stable isotopes in rainfall as a paleoclimate and hydrological tracer.

Stable isotope composition of walleye: 15N accumulation with age and area-specific differences in δ13C

2001 ◽  
Vol 58 (6) ◽  
pp. 1253-1260 ◽  
Author(s):  
Nathanael C Overman ◽  
Donna L Parrish
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Carbon Isotope ◽  
Trophic Position ◽  
Isotope Composition ◽  
Isotope Analysis ◽  
Isotopic Fractionation ◽  
Stomach Content Analysis ◽  
Metabolic Effects ◽  
N Accumulation

Stable nitrogen and carbon isotope ratios were measured for walleye (Stizostedion vitreum) collected across Lake Champlain, Vermont, to determine relationships between isotopic composition and diet, location of capture, length, weight, and age. Variation in δ13C values reflected area-specific differences in isotopic composition of organisms collected across the lake. A critical assumption in the application of isotope techniques is that a predictable relationship exists between the diet and isotopic composition of an organism. Our results indicate that isotopic fractionation factors may not be independent of age as has largely been assumed. By combining stable nitrogen and carbon isotope analysis with conventional stomach content analysis, we documented significant age effects in the δ15N composition of adult walleye that were not attributable to observed changes in diet. Age accounted for 81% of the variation in δ15N values of walleye (ages 2–27, N = 65, δ15N range = 15.3–19.2‰), providing evidence supporting 15N accumulation over the life span of walleye. Therefore, the risk of making faulty inferences of trophic position and food web interactions based on δ15N values may be increased when age is unknown. Our results indicate that metabolic effects associated with age require greater consideration in applications of stable isotope analysis.

scholarly journals The O and H stable isotope composition of freshwaters in the British Isles. 2. Surface waters and groundwater

2003 ◽  
Vol 7 (2) ◽  
pp. 183-195 ◽  
Author(s):  
W. G. Darling ◽  
A. H. Bath ◽  
J. C. Talbot
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Isotopic Composition ◽  
Surface Waters ◽  
Isotope Composition ◽  
Weighted Average ◽  
Ice Age ◽  
Annual Rainfall ◽  
British Isles ◽  
Contour Maps

Abstract. The utility of stable isotopes as tracers of the water molecule has a long pedigree. The study reported here is part of an attempt to establish a comprehensive isotopic "baseline" for the British Isles as background data for a range of applications. Part 1 of this study (Darling and Talbot, 2003) considered the isotopic composition of rainfall in Britain and Ireland. The present paper is concerned with the composition of surface waters and groundwater. In isotopic terms, surface waters (other than some upland streams) are poorly characterised in the British Isles; their potential variability has yet to be widely used as an aid in hydrological research. In what may be the first study of a major British river, a monthly isotopic record of the upper River Thames during 1998 was obtained. This shows high damping of the isotopic variation compared to that in rainfall over most of the year, though significant fluctuations were seen for the autumn months. Smaller rivers such as the Stour and Darent show a more subdued response to the balance between runoff and baseflow. The relationship between the isotopic composition of rainfall and groundwater is also considered. From a limited database, it appears that whereas Chalk groundwater is a representative mixture of weighted average annual rainfall, for Triassic sandstone groundwater there is a seasonal selection of rainfall biased towards isotopically-depleted winter recharge. This may be primarily the result of physical differences between the infiltration characteristics of rock types, though other factors (vegetation, glacial history) could be involved. In the main, however, groundwaters appear to be representative of bulk rainfall within an error band of 0.5‰ δ18O. Contour maps of the δ18O and δ2H content of recent groundwaters in the British Isles show a fundamental SW-NE depletion effect modified by topography. The range of measured values, while much smaller than those for rainfall, still covers some ‰ for δ18O and 30‰ for δ2H. Over lowland areas the "altitude effect" is of little significance, but in upland areas is consistent with a range of –0.2 to –0.3‰ per 100 m increase in altitude. Groundwaters dating from the late Pleistocene are usually modified in δ18O and δ2H owing to the effects of climate change on the isotopic composition of rainfall and thus of recharge. Contour maps of isotopic variability prior to 10 ka BP, based on the relatively limited information available from the British Isles, allow a first comparison between groundwaters now and at the end of the last Ice Age. The position of the British Isles in the context of the stable isotope systematics of NW Europe is reviewed briefly. Keywords: Stable isotopes, surfacewaters, groundwater, British Isles

scholarly journals Silicon isotope fractionation and uptake dynamics of three crop plants: laboratory studies with transient silicon concentrations

2020 ◽  
Author(s):  
Daniel A. Frick ◽  
Rainer Remus ◽  
Michael Sommer ◽  
Jürgen Augustin ◽  
Friedhelm von Blanckenburg
Keyword(s):  
Stable Isotope ◽  
Plant Growth ◽  
Diffusion Process ◽  
Silicic Acid ◽  
Isotope Fractionation ◽  
Crop Plants ◽  
Transfer Efficiency ◽  
Silicon Isotope ◽  
Fractionation Factor ◽  
Stable Isotope Fractionation

Abstract. Silicon has been recognized an important element in global biogeochemical cycles for a long time. Recently, its relevance for global crop production gains increasing attention. Silicon is beneficial for plant growth and is taken up in considerable amounts by crops, likewise rice or wheat. The incorporation of silicic acid from the soil solution into the plants is accomplished by a variety of strategies (rejective, passive and active) that are subject to an intense debate. To forge a new perspective on the underlying processes, we investigated how the silicon stable isotope fractionation during plant growth depends on uptake strategy, transpiration, water use, and Si transfer efficiency. Crop plants with a rejective (tomato, Solanum lycopersicum and mustard, Sinapis alba) and active (spring wheat, Triticum aestivum) uptake were hydroponically grown for 6 weeks. Using inductively coupled plasma mass spectrometry, the silicon amounts and the isotopic composition of the nutrient solution, the roots, and the shoots were determined. Wheat revealed the highest Si transfer efficiency from root to shoot followed by tomato and mustard. All three species preferentially incorporated light 28Si, with a fractionation factor 1000∙ln(α) of −0.33 ‰ (tomato), −0.55 ‰ (mustard) and −0.43 ‰ (wheat). Even though the rates of active and passive Si root uptake differ, the physico-chemical processes governing Si uptake and stable isotope fractionation do not, they are governed by a diffusion process. In contrast, the transport of silicic acid from the roots to the shoots depends on the preceding precipitation of silicic acid in the roots and the presence of active transporters at the root endodermis. Plants with a significant biogenic silica precipitation in roots (mustard, and wheat), preferentially transport silicon enriched in 30Si into their shoots, whereas the transport in tomato is governed by a diffusion process and hence preferentially transports light silicon 28Si into the shoots.

scholarly journals Extreme Zr stable isotope fractionation during magmatic fractional crystallization

2019 ◽  
Vol 5 (12) ◽  
pp. eaax8648 ◽  
Author(s):  
Mauricio Ibañez-Mejia ◽  
François L. H. Tissot
Keyword(s):  
Stable Isotope ◽  
Closed System ◽  
Isotope Fractionation ◽  
Isotope Composition ◽  
Isotopic Fractionation ◽  
Compositional Evolution ◽  
Stable Isotope Fractionation ◽  
Zircon Crystallization ◽  
Single Zircon ◽  
Isotope Systematics

Zirconium is a commonly used elemental tracer of silicate differentiation, yet its stable isotope systematics remain poorly known. Accessory phases rich in Zr4+ such as zircon and baddeleyite may preserve a unique record of Zr isotope behavior in magmatic environments, acting both as potential drivers of isotopic fractionation and recorders of melt compositional evolution. To test this potential, we measured the stable Zr isotope composition of 70 single zircon and baddeleyite crystals from a well-characterized gabbroic igneous cumulate. We show that (i) closed-system magmatic crystallization can fractionate Zr stable isotopes at the >0.5% level, and (ii) zircon and baddeleyite are isotopically heavy relative to the melt from which they crystallize, thus driving chemically differentiated liquids toward isotopically light compositions. Because these effects are contrary to first-order expectations based on mineral-melt bonding environment differences, Zr stable isotope fractionation during zircon crystallization may not solely be a result of closed-system thermodynamic equilibrium.

scholarly journals Isotopic composition of precipitation in Poland: a 44-year record

2019 ◽  
Vol 67 (6) ◽  
pp. 1637-1648 ◽  
Author(s):  
Marek Duliński ◽  
Kazimierz Różański ◽  
Anna Pierchała ◽  
Zbigniew Gorczyca ◽  
Michał Marzec
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Isotope Composition ◽  
Environmental Isotopes ◽  
Monthly Precipitation ◽  
Stable Isotope Composition ◽  
Tritium Content ◽  
European Continent ◽  
The North ◽  
The North Atlantic Oscillation

Abstract Isotopic composition of precipitation (2H/1H and 18O/16O isotope ratios, tritium content) is nowadays widely used in numerous applications of environmental isotopes—most notably in hydrology, climatology and biogeochemistry. Here we present a long record (44 years) of stable isotope composition and tritium content in monthly precipitation available for the Krakow station (southern Poland). Krakow is the only site in Poland for which long-term record of the isotopic composition of monthly precipitation is available. The tritium data are discussed here in the context of generally declining levels of bomb tritium in the global atmosphere and growing influence of technogenic emissions of this isotope. Two aspects of temporal variability of stable isotope composition of precipitation collected in Krakow are discussed here: (i) seasonality and (ii) interannual changes of δ18O and δ2H signal. Whereas the seasonality of stable isotope signal is generated mainly by seasonally varying the degree of rainout of air masses bringing moisture from the source regions (subtropical Atlantic Ocean) to the centre of the European continent, the North Atlantic Oscillation seems to govern interannual changes of δ18O and δ2H on the decadal timescale. Progressing warming of the local atmosphere, in the order of 1.8 °C in the past four decades, leaves its imprint in stable isotope signal measured in Krakow precipitation; the slope of isotope–temperature relationship is in the order of 0.50‰/°C for δ18O and 3.5‰/°C for δ2H.

scholarly journals Spatial variability of northern Iberian rainfall stable isotope values: Investigating climatic controls on daily and monthly timescales

2020 ◽  
Author(s):  
Ana Moreno ◽  
Miguel Iglesias ◽  
Cesar Azorin-Molina ◽  
Carlos Pérez-Mejías ◽  
Miguel Bartolomé ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Time Scales ◽  
Air Temperature ◽  
Isotope Composition ◽  
Source Region ◽  
Precipitation Amount ◽  
Relative Role ◽  
Northern Spain

Abstract. This article presents for the first time a large dataset of rainfall isotopic measurements (d18Op and d2Hp) sampled every day or every two days from seven sites in a west-to-east transect across northern Spain for 2010–2017. The main aim of this study is to: (1) characterize rainfall isotopic variability in northern Spain at daily and monthly time scales, and (2) assess the principal influencing factors determining rainfall isotopic variability. This comprehensive spatio-temporal approach allows exploring the role of air mass source in determining the isotopic composition of rainfall in northern Iberia by using back-trajectories; Atlantic fronts are found to be the dominant source of northern Iberia rain events studied. The relative role of air temperature and rainfall amount in determining the stable isotope composition of precipitation changes along the west-to-east transect. Air temperature appears to be the most significant influence on d18Op at daily and monthly time scales with the highest air temperature-d18Op dependency found for the Pyrenean station while a few sites in the transect show a significant negative correlation with precipitation amount. Distance from the coast, site elevation, and moisture source region (Atlantic versus Mediterranean) also significantly modulate the d18Op values and ranges but the type of precipitation (convective vs frontal rainfall) plays a key control, with convective rainfall associated with higher d18Op values. This dataset of the rainfall isotopic composition represents another step forward towards developing a more detailed, mechanistic framework for interpreting stable isotopes in rainfall as a palaeoclimate and hydrological tracer.

scholarly journals Storage Changes Stable Isotope Composition of Cucumbers

2021 ◽  
Vol 5 ◽  
Author(s):  
Micha Horacek ◽  
Wolfgang Papesch
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Isotope Composition ◽  
Isotopic Signature ◽  
Stable Isotope Composition ◽  
Vegetable Food ◽  
O Isotope ◽  
Linear Correlations ◽  
Special Relevance ◽  
Reference Samples

Vegetable food stuff produced under controlled and identical conditions from one farm of identical “age” (batch) has a similar isotopic composition. This fact can be used to control the origin of vegetables. This question is of special relevance when food-contaminations have to be traced back to the producer, or certain production claims have to be controlled. However, as vegetables are harvested, brought to whole-sale merchants and to retail shops, where they remain until being bought by the consumer, one has to consider possible changes in isotopic composition during this transfer period, when comparing vegetables of questioned origin with reference samples taken directly from the field/producer. We investigated changes in the isotope composition of vegetables during storage by studying as an example cucumbers from one batch. We stored the cucumbers in a vegetable storage under controlled conditions and removed one sample every day and analyzed its isotopic composition. We found changes in the δ15N and δ18O isotope values over the investigated period of 21 days, with both parameters showing positive linear correlations, and maximum enrichments with time of more than 1.5‰ for δ15N and more than 2‰ for δ18O. However, within the interval the samples remained in a saleable condition the isotope variations remained more or less within the variability of the sample batch. Our study demonstrates that changes in the isotopic signature in vegetables might occur after harvest during storage and have to be taken into account when (commercial) samples collected in a market are investigated.

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