Oxygen Isotope Analysis

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Triple oxygen isotope analysis of nitrate using isotope exchange   cavity ringdown laser spectroscopy

Triple oxygen isotope analysis of nitrate using isotope exchange cavity ringdown laser spectroscopy

After equilibration (same conditions as section 2.2.1), the tubes were rapidly placed in an ice bath. Prior to analysis, water was frozen into the base of the break-seal tube by immersion in liquid nitrogen. Subsequently, the tube was scored with a diamond cutter, broken to a fixed height of 25 mm, and then quickly inserted into the 2-mL septum-capped vials used by the Picarro A0325 autosampler 45 . Prior to the analysis, the solution was neutralized by adding 4.2 L of the ST-NaOH solution (10N).

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Determining the Authenticity of Artifacts by Oxygen Isotope Analysis

Determining the Authenticity of Artifacts by Oxygen Isotope Analysis

The isotopic composition of authigenic carbonate that might form as a precipitate on a surface would be deter- mined by kinetic reactions. Kinetic reactions, as opposed to speleothem equilibrium reactions, will not preserve any of the original environmental oxygen isotopic signa- tures of the rain. The patina is composed of any mixture of substances both authigenic and allogenic. It can in- clude the incorporation of a multitude of different parti- cles from many sources. A patina can host clays, silts and sands of any composition, precipitated salts, including carbonates, microfossils pollen and dust. The dust repre- sents anything that the wind can transport, from near or far locations. The content and sources of dust in Israel in general have been well studied [6] and can be a mixture of whatever carbonate particles happen to be part of the local environment and/or particles which have been transported as far as a thousand kilometers from the Sa- haran or Arabian deserts [6,37,38]. This composition of the various carbonate sources contribute to the atmos- pheric dust and soil and their oxygen isotopic composi- tion can vary greatly. Thus, isotopic composition of the naturally occurring carbonates in the Jerusalem area can
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Oxygen isotope analysis of the eyes of pelagic trilobites: Testing the application of sea temperature proxies for the Ordovician

Oxygen isotope analysis of the eyes of pelagic trilobites: Testing the application of sea temperature proxies for the Ordovician

lens SIMS cuticle Dentist drill cuticle Micro-mill cuticle Micro-mill sediment SIMS Carolinites sibericus sediment Dentist drill sediment Micro-mill sediment Dentist drill sediment Denti[r]

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Pliocene diatom and sponge spicule oxygen isotope ratios from the Bering Sea: isotopic offsets and future directions

Pliocene diatom and sponge spicule oxygen isotope ratios from the Bering Sea: isotopic offsets and future directions

Another form of biogenic silica commonly found in sedi- ments is siliceous sponge spicules (structural elements which support the skeleton of the animal; phylum Porifera, classes Demospongiae and Hexactinellida). Sponge spicules come in a variety of shapes and sizes, ranging from micrometres to metres long (Uziz et al., 2003; Jochum et al., 2012), and are often seen as needle-like structures with a hollow central canal (axial canal) (Müller et al., 2007). The crystalline na- ture of the sponge spicule is similar to that of diatoms (Sand- ford, 2003); however, the processes involved in their synthe- sis are different. Diatom frustules are formed from an or- ganic template onto which a supersaturated solution of silicic acid is deposited, supplemented by passive diffusion across the cell membrane (Thamatrakoln and Hildebrand, 2008), whereas sponge spicules are formed in an enzymatic way, using silicateins, within the sponge organism (Maldonado et al., 2011; Wang et al., 2012). Additionally, diatoms live in the photic zone of the water column whereas sponges are entirely benthic organisms, so the two groups of organisms reflect environmental conditions in different parts of the wa- ter column. The use of oxygen isotope analysis of sponge spicules (δ 18 O sponge ) is rare, and those studies that have been
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Reconstructing Fire Severity From the Oxygen-Isotope Compositions of Plant Char

Reconstructing Fire Severity From the Oxygen-Isotope Compositions of Plant Char

starting material at all temperatures; however, both ash and char were forming at higher temperatures (>300-500°C). The thickness of the ash layer increased with increasing temperature, particularly for the lid-off sample treatment. The formation of an ash layer, especially on wood, can create a protective coating that insulates the remaining plant material from heat and restricts oxygen movement to the interior of the sample, resulting in ideal conditions for char formation (Schumacher et al. 2011). The initial 2 g starting amount for samples charred at temperatures above 600°C often resulted in the entire sample being converted to ash in the open air (lid-off) experiment, leaving little to no char remaining for oxygen-isotope analysis. As such, varying amounts of starting material were used when this experiment was repeated. Slightly more material (~3-4 g) was used at higher temperatures for the lid-off sample treatment, where ash formation was most prominent, and less material (approximately 1 g) was used at lower temperatures where percent weight loss was minimal (Table 3.1). Plant samples charred for 5 minutes were originally formed using 1 g of material, whereas 1 to 3 g of material was used for the lid-off sample treatment (n.b., only 1 g of material was still used for the lid-on treatment) when the experiment was repeated.
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Geologic and isotopic investigations of the early Cretaceous Sierra Nevada Batholith, Tulare Co , CA, and the Ivrea Zone, NW Italian Alps: examples of interaction between mantle derived magma and continental crust

Geologic and isotopic investigations of the early Cretaceous Sierra Nevada Batholith, Tulare Co , CA, and the Ivrea Zone, NW Italian Alps: examples of interaction between mantle derived magma and continental crust

Table 5,1: Major element chemistry, location and oxygen Isotope analysis of samples from the central Mafic Complex, Ivrea Zone, Italy.. VS l06b inclusion roof dior~e.[r]

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Phosphate stable oxygen isotope variability within a temperate agricultural soil

Phosphate stable oxygen isotope variability within a temperate agricultural soil

Unfortunately, the described sampling design of Peukert et al. (2012) was fl awed due to a mis-interpretation of the requirements needed for an ef fi cient statistical analysis. The design resulted in: (i) large areas of gross under-sampling or voids and (ii) areas of preferen- tial or clustered sampling due to the chosen sampling scheme. Both fl aws also interact and compound each other. Given this, the direct ap- plication of many statistical methods is likely to be inef fi cient and sub- optimal, resulting in biased outputs (Diggle et al., 2010; Gelfand et al., 2012; Olea, 2007). As a consequence, all of this study's statistical analy- ses had to be conducted in a manner that would account for this sub-op- timal sample design.
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Environmental and physiological controls over carbon and oxygen isotope variations in plants

Environmental and physiological controls over carbon and oxygen isotope variations in plants

I specifically report on daily variation in the stable isotopes of C, N, 0 and H in the water and dry matter of xylem, phloem, leaves, and fruits of lupin, a legume commonly grown as a g[r]

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Stable Oxygen and Deuterium Isotope Techniques to Identify Plant Water Sources

Stable Oxygen and Deuterium Isotope Techniques to Identify Plant Water Sources

From Table 3 above, the highest mean value in the quarter root and the lowest root in the tertiary can be seen at the depth of 0 - 20. At the depth of 20 - 50 cm, the highest value rates were found in the primary root, where as the lowest values were obtained in the tertiary. At the depth of 50 - 100 cm, the highest value was found in the quarter root. At the depth of 100 - 150, the highest rate was found in the root quarter, while the lowest was found in the primary root. In addition, the average depth of 150 - 200 contained the highest value on the secondary root, where as the lowest value was found in the primary and quarter roots. Based on the information in Table 3 it can be concluded that the rooting of oil palm is more dominant at the depths of 0 - 20 and 20 - 50 cm. According to Fauzi et al. [14], the roots of secondary, tertiary, and quarter grow parallel to the ground surface roots and even to the tertiary and quarter of the upper layer or to the places that contain lots of nutrients. Furthermore, Iyung [4] stated that most oil palm roots are near the soil surface and only a few roots of palm oil are at the depth of 90 cm. Although ground water surface (watertable) is quite deep, active root system is generally located at the depth of 5 - 35 cm, while tertiary roots are located at the depth of 10 - 30 cm. The result analysis of the root samples at different soil depths in this study is shown in Figure 6.
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Post mortem oxygen isotope exchange within cultured diatom silica

Post mortem oxygen isotope exchange within cultured diatom silica

signature, with implications for laboratory protocols and interpretation of palaeoclimate records. Although the mechanisms remain uncertain, it is suggested that this secondary alteration may be related to silica condensation, associated with the loss of hydroxyl silica and water in the formation of new Si ‐ O ‐ Si bonded silica. In the laboratory, the amount of oxygen affected during storage is positively correlated with temperature. The associated isotope fractionation conforms to the range of extrapolated models based on high ‐ temperature inorganic silica ‐ water oxygen isotope calibrations. The range of δ 18 O
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Spatial patterns in the oxygen isotope composition of daily rainfall in the British Isles

Spatial patterns in the oxygen isotope composition of daily rainfall in the British Isles

Spatial patterns in the oxygen isotope composition of daily rainfall in the British.. 1 Department of Earth Sciences, The University of Adelaide, Adelaide, South.[r]

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A method for stable carbon isotope ratio and concentration measurements of ambient aromatic hydrocarbons

A method for stable carbon isotope ratio and concentration measurements of ambient aromatic hydrocarbons

Measuring the isotope composition of VOCs in the atmo- sphere is challenging due to the high precision and accu- racy necessary to derive meaningful information. Rudolph et al. (1997) published a method for compound-specific de- termination of the stable carbon isotopic composition for atmospheric VOCs at sub-ppbV levels. The uncertainty of measured isotope ratios was close to 0.5 ‰, and Rudolph et al. (1997) suggested that further improvements in method may allow a precision close to 0.1 ‰. Within several years different research groups published results of stable carbon isotope measurements for a variety of atmospheric VOCs (Anderson et al., 2004; Czapiewski et al., 2002; Iannone et al., 2003, 2005; Irei et al., 2006; Norman et al., 1999; Rogers and Savard, 1999; Rudolph et al., 2002, 2003; Smallwood et al., 2002; Thompson et al., 2003). Nevertheless, the num- ber of publications on isotopic composition measurements and their application is still quite limited due to the need for elaborate and expensive experimental techniques and chal- lenging data interpretation (Eckstaedt et al., 2011; Fisseha et al., 2009; Giebel et al., 2010; Iannone et al., 2005, 2009, 2010; Irei et al., 2006; Li et al., 2010; Moukhtar et al., 2011). An overview of existing techniques to measure stable carbon isotope ratios of VOCs is given in a recent paper (Gensch et al., 2014).
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University of New Hampshire University of New Hampshire Scholars' Repository

University of New Hampshire University of New Hampshire Scholars' Repository

Oxygen and carbon isotope record for the Early and Middle Miocene in the central equatorial Pacific (Leg 85) and paleoceanographic implications, Inigial Rep. Deep [r]

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Coupled measurements of δ18O and δD of hydration water and salinity of fluid inclusions in gypsum from the Messinian Yesares Member, Sorbas Basin (SE Spain)

Coupled measurements of δ18O and δD of hydration water and salinity of fluid inclusions in gypsum from the Messinian Yesares Member, Sorbas Basin (SE Spain)

We made tandem measurements of the isotopic composition of gypsum hydration water and the salinity of fluid inclusions to test whether Messinian gypsum retained the original isotopic compo- sition and salinity of the mother water. After correction of oxygen and hydrogen isotopes of gypsum hydration water for known frac- tionation factors, we show that the δ 18 O and δ D of the mother water is highly correlated with salinity of fluid inclusions in gyp- sum deposits of Cycle 6 within the Yesares Member. The intercepts of the regression equations (i.e., at zero salinity) define the iso- tope composition of the freshwater endmember. These values are within error of the average isotope composition of precipitation and groundwater data from the local region of Almería today. This agreement provides strong evidence that the gypsum hydration water has retained its isotope composition and has not undergone postdepositional exchange.
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Ferroan dolomite cement in Cambrian sandstones: burial history and hydrocarbon generation of the Baltic sedimentary basin

Ferroan dolomite cement in Cambrian sandstones: burial history and hydrocarbon generation of the Baltic sedimentary basin

The conditions and timing of carbonate cementation in Cambrian sandstones of the Baltic sedimentary basin were determined by oxygen and carbon stable isotope and chemical data in combination with optical and cathodolumi- nescence petrographic studies. Studied samples represent a range in present burial depth from 340 to 2150 m. The carbonate cement is dominantly ferroan dolomite that occurs as dispersed patches of poikilotopic crystals. Tem- peratures of dolomite precipitation, based on δ 18 O values, range from 27°C in the shallow buried to 95°C in the deep

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Extended orbitally forced palaeoclimatic records from the equatorial Atlantic Ceara Rise

Extended orbitally forced palaeoclimatic records from the equatorial Atlantic Ceara Rise

in amplitude every ~41ka, a very strong eccentricity signal in the carbon isotope records, and a strong, but probably local, imprint of climatic precession on the coarse fraction and magnetic susceptibility records. Our data allowed us to evaluate how the interaction of long, multi-million year beats in the Earth's eccentricity and obliquity are implicated in the waxing and waning of ice-sheets, presumably on Antarctica. Our refined age model confirms the revised age of the Oligocene-Miocene boundary, previously established by analysis of the lithological data, and allows a strong correlation with the geomagnetic time scale by comparison with data from ODP Site 1090, Southern Ocean.
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Stable oxygen and hydrogen isotope fractionation factors for the Goethite (hematite)-water system

Stable oxygen and hydrogen isotope fractionation factors for the Goethite (hematite)-water system

isotope of the initial water from which precursor ferrihydrite formed. The goethite is formed by the dissolution of ferrihydrite and subsequent precipitation as goethite [10]. In the goethite crystal growth process the isotopic composition of the initial ferrihydrite may be lost. Also, goethite crystals took longer (~60 h) to form than the hematite (~48 h) and, therefore, mineral-water isotopic equilibrium may have been approached. The enrichment factor ( Fe-oxide-Water ) decreased systematically with the

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Inter-annual tropical Pacific climate variability in an isotope-enabled CGCM: implications for interpreting coral stable oxygen isotope records of ENSO

Inter-annual tropical Pacific climate variability in an isotope-enabled CGCM: implications for interpreting coral stable oxygen isotope records of ENSO

gression at each location of interest, the assumption has been made that the modern spatial slope between these paired ob- servations of these variables (LeGrande and Schmidt, 2006) may usefully represent the temporal slopes. However, ex- isting work with the isotope-enabled Goddard Institute for Space Studies ModelE-R CGCM suggests that substantial differences may exist between the temporal and spatial gra- dients of isotopic and conservative hydrological cycle trac- ers (LeGrande and Schmidt, 2009). Therefore, an additional question that may be addressed using fully isotope-enabled CGCMs is the evaluation of the uncertainties associated with the pseudo-coral approach, at least within the climate of that model.
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Multiple negative carbon-isotope excursions during the Carnian Pluvial Episode (Late Triassic)

Multiple negative carbon-isotope excursions during the Carnian Pluvial Episode (Late Triassic)

The interval punctuated by the NCIEs within the Carnian, corresponding to the CPE, was a time of overall global 18 O analysis of conodont apatite (Fig. 9; Sun et al., 2016 and references therein), and was closely related to environmental changes that are widespread at least across the western Tethys (Fig. 9). Three to four distinct siliciclastic-dominated intervals are traditionally recognized in Carnian (Julian 2 Tuvalian 2) stratigraphic successions of the western Tethys realm (e.g., see summary in Roghi et al., 2010; Fig. 9). In the Dolomites, such terrigenous levels are located at the base of the Borca Mb., in the lower part of the Dibona Mb., and in the lower part of the Lagazuoi Mb. of the Heiligkreuz Formation. At the base of the Travenanzes Fm. a mixed carbonate terrigenous level is also present (Fig. 2). These distinct levels can be recognized in other sections, and are biostratigraphically correlated within the western Tethyan realm (Roghi et al., 2010).
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Stable oxygen isotope variability in two contrasting glacier river  catchments in Greenland

Stable oxygen isotope variability in two contrasting glacier river catchments in Greenland

Analysis of stable oxygen isotopes is a very useful tech- nique to investigate water provenance in glacial river sys- tems. Stable oxygen isotopes are natural conservative trac- ers in low-temperature hydrological systems (e.g. Moser and Stichler, 1980; Gat and Gonfiantini, 1981; Haldorsen et al., 1997; Kendall et al., 2014). Consequently, oxygen iso- topes can be applied to determine the timing and origin of changes in water sources and flow paths because different water sources often have isotopically different compositions due to their exposure to different isotopic fractionation pro- cesses. Since the 1970s, this technique has been widely used for hydrograph separation (Dinçer et al., 1970). Most of- ten a conceptual two-component mixing model is applied, where an old-water component (e.g. groundwater) is mixed with a new-water component (e.g. rain or snowmelt), assum- ing that both components have spatial and temporal homoge- neous compositions. The general mixing model is given by the equation
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