Silver isotope analysis of gold nuggets: An appraisal of instrumental isotope fractionation effects and potential for high-resolution tracing of placer gold

South American Monsoon System (SAMS) and its main feature, the South American Convergence Zone (SACZ) are responsible for the major distribution of moisture in South America. The current work presents a novel high-resolution oxygen isotope record (&#948;18O) based on speleothems from southwest Amazon basin (Brazil), right at SAMS' core region and SACZ onset, where there is still a gap of high resolution paleoclimate records. The novel &#948;18O&#160;record presents an average of 3 year-resolution, composed by 1344 stable isotope analysis performed in two speleothems with a well-resolved chronology (37 U/Th ages) with average errors <1%. This work aims to describe the rainfall variability of the core region of the South American monsoon for the last 3k years and to take a broader look at precipitation patterns over Amazon basin. The Rond&#244;nia &#948;18O record shows three main stages throughout this time period. The first is from -1000 to ~400 CE, where it&#8217;s in accordance with most of other paleorecords from the Amazon basin. the second segment &#160;is from ~400 to 1200 CE, when there is a continuous increase in the &#948;18O record until it reaches its highest values around 850 CE during the MCA (800-1200 CE), which is in accordance with western Amazon records, whilst the record in eastern Amazon presents an opposite trend. Thus, a precipitation dipole over Amazon emerges from ~400 CE onwards, majorly triggered by anomalous climate changes such as MCA, where western (eastern) Amazon is drier (wetter). During LIA (1450-1800 CE), on the other hand, Rond&#244;nia record presents its lowest values, also agreeing with western records and with records under the influence of SACZ whilst on eastern Amazon a drier period is established. Therefore, with this novel paleoclimate record located at the core region of SAMS, it's possible to evidence the dynamics of the precipitation dipole over the Amazon region, as well as understand the SACZ intensity variations.

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Mass spectrometric measurement of hydrogen isotope fractionation for the reactions of chloromethane with OH and Cl

10.5194/acp-2018-8 ◽

2018 ◽

Author(s):

Frank Keppler ◽

Enno Bahlmann ◽

Markus Greule ◽

Heinz Friedrich Schöler ◽

Julian Wittmer ◽

...

Keyword(s):

Hydrogen Isotope ◽

Isotope Fractionation ◽

Isotope Effects ◽

Isotope Analysis ◽

Isotope Ratio Mass Spectrometry ◽

Detailed Knowledge ◽

Mass Spectrometric Measurement ◽

Isotopic Analyses ◽

Chlorine Radicals ◽

Stable Hydrogen Isotope

Abstract. Chloromethane (CH3Cl) is an important provider of chlorine to the stratosphere but yet lacks detailed knowledge of its budget. Stable isotope analysis is potentially a powerful tool to constrain CH3Cl flux estimates. The largest degree of isotope fractionation is expected to occur for deuterium in CH3Cl in the hydrogen abstraction reactions with its main sink reactant tropospheric OH and its minor sink reactant Cl atoms. We determined the isotope fractionation by stable hydrogen isotope analysis of the fraction of CH3Cl remaining after reaction with hydroxyl and chlorine radicals in a 3.5 m3 Teflon smog-chamber at 293 ± 1 K. We measured the increasing stable hydrogen isotope values of the unreacted CH3Cl using compound specific thermal conversion isotope ratio mass spectrometry. The isotope fractionations of CH3Cl for the reactions with hydroxyl and chlorine radicals were found to be −242 ± 7 mUr (or ‰) and −280 ± 11 mUr, respectively. For comparison, we performed similar experiments using methane (CH4) as the target compound with OH and obtained a fractionation constant of −205 ± 6 mUr which is in good agreement with values previously reported. The observed large kinetic isotope effects are helpful when employing isotopic analyses of CH3Cl in the atmosphere to improve our knowledge of its atmospheric budget.

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A flow-through reaction cell that couples time-resolved X-ray diffraction with stable isotope analysis

Journal of Applied Crystallography ◽

10.1107/s0021889811000525 ◽

2011 ◽

Vol 44 (2) ◽

pp. 429-432 ◽

Cited By ~ 17

Author(s):

Andrew J. Wall ◽

Peter J. Heaney ◽

Ryan Mathur ◽

Jeffrey E. Post ◽

Jonathan C. Hanson ◽

...

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Fractionation ◽

Isotope Analysis ◽

X Ray Diffraction ◽

Reaction Cell ◽

Time Resolved ◽

X Ray ◽

Flow Through

A non-metallic flow-through reaction cell is described, designed forin situtime-resolved X-ray diffraction coupled with stable isotope analysis. The experimental setup allows the correlation of Cu isotope fractionation with changes in crystal structure during copper sulfide dissolution. This flow-through cell can be applied to many classes of fluid–mineral reactions that involve dissolution or ion exchange.

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Lead and Silver Production in the Montevecchio Basin (Western Sardinia, Italy)

MRS Proceedings ◽

10.1557/proc-462-411 ◽

1996 ◽

Vol 462 ◽

Author(s):

G.M. Ingo ◽

T. Agus ◽

R. Ruggeri ◽

A. Amore Bonapasta ◽

G. Bultrini ◽

...

Keyword(s):

Isotope Fractionation ◽

Lead Isotope ◽

Isotope Analysis ◽

Ore Deposits ◽

Smelting Process ◽

Metal Production ◽

Lead Isotope Analysis ◽

Rule Out ◽

Good Agreement

ABSTRACTLead slags and lead pieces, chronologically related to the Punic and Roman periods (IV BC - II AC), have been found at Bocche di Sciria, in the basin of the Montevecchio mine (south-western Sardinia, Italy). Furthermore, along the coast of this area over than 20 Punic and Roman shipwrecks with charges of lead ingots have been found. These materials indicate intense pyrometallurgical activities and the presence of metal production centres very close to the metal ore deposits. The microchemical studies of the slags have shown that they can be associated to a smelting process for lead and silver production. Furthermore, lead isotope analysis has been carried out for lead ores from Montevecchio and for the lead slags, litharge, lead pieces found there. The results for lead ores are in good agreement with literature and the scatter of data for slags, litharge and lead pieces suggest to rule out a lead isotope fractionation in ancient lead and silver production.

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High-resolution stable isotope analysis of tree rings: implications of 'microdendroclimatology' for palaeoenvironmental research

The Holocene ◽

10.1177/095968369500500408 ◽

1995 ◽

Vol 5 (4) ◽

pp. 457-460 ◽

Cited By ~ 74

Author(s):

N.J. Loader ◽

V.R. Switsur ◽

E.M. Field

Keyword(s):

High Resolution ◽

Stable Isotope ◽

Tree Rings ◽

Stable Isotope Analysis ◽

Isotope Analysis

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High resolution infrared diode laser spectroscopy for isotope analysis—Measurement of isotopic carbon monoxide

Applied Physics Letters ◽

10.1063/1.96722 ◽

1986 ◽

Vol 48 (10) ◽

pp. 619-621 ◽

Cited By ~ 18

Author(s):

Peter S. Lee ◽

Richard F. Majkowski

Keyword(s):

Carbon Monoxide ◽

High Resolution ◽

Diode Laser ◽

Laser Spectroscopy ◽

Isotope Analysis ◽

Diode Laser Spectroscopy ◽

Analysis Measurement

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A Modified Method to Calculate Dual Isotope Slopes for the Natural Attenuation of Organic Pollutants in the Environment

10.21203/rs.3.rs-180409/v1 ◽

2021 ◽

Author(s):

Jin-Ru Feng ◽

Hong-Gang Ni

Keyword(s):

Reaction Mechanism ◽

Isotope Fractionation ◽

Isotope Analysis ◽

Aerobic Biodegradation ◽

Two Dimensional ◽

Data Set ◽

Dual Isotope ◽

Sulfate Reducing ◽

Modified Method ◽

Novel Method

Abstract Two-dimensional compound specific isotope analysis has become a powerful tool to distinguish reaction mechanism. Lambda (Λ), an essential and important parameter for processing two-dimensional isotope fractionation data, is specific to a reaction mechanism. In the present article, we modified the existing algorithms for Lambdas based on the review of the current methods. Specifically, through regressing [(1000+δE0,2)*(n1*x2)*ΔδEbulk,1] versus [(1000+δE0,1)*(n2*x1)*ΔδEbulk,2] by York method, a novel method was developed to calculate Λs. The improved method eliminates both the influence of non-reacting position and the initial isotope signatures. Furthermore, this method retains the advantages of two-dimension isotope plot, which eliminates contributions from commitment to catalysis, no need to determine fraction of remaining substrate and can be constructed even from filed data. At the same time, one sample t test is applied to generate 95% confidence interval of data set of Λris for various reaction mechanisms. The range of 5.67-24.8, 8.54-9.80, 0.51-8.35, 25.2-36.8, 7.09-21.9 are responsible for oxidation of C-H bonds (ZC=1, ZH=3), oxidation of C-H bonds (ZC=1,ZH=4), aerobic biodegradation of benzene (ZC=6,ZH=6), methanogenic or sulfate-reducing biodegradation of benzene (ZC=6,ZH=6), and nitrate-reducing biodegradation of benzene (ZC=6,ZH=6). The accumulation and correction of these values will make the data measured in the field easier to interpret.

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Revealing ancient gold parting with silver and copper isotopes: implications from cementation experiments and for the analysis of gold artefacts

Archaeological and Anthropological Sciences ◽

10.1007/s12520-021-01369-2 ◽

2021 ◽

Vol 13 (9) ◽

Author(s):

Daniel Berger ◽

Michael Brauns ◽

Gerhard Brügmann ◽

Ernst Pernicka ◽

Nicole Lockhoff

Keyword(s):

Trace Element ◽

Isotope Fractionation ◽

Copper Alloys ◽

Pure Gold ◽

Copper Isotopes ◽

Gold Silver ◽

Analytical Proof ◽

Gold Refining ◽

Isotope Systematics ◽

Silver Isotope

AbstractGold parting enabled the production of very pure gold for various purposes from the sixth century BC onwards, but analytical proof of this pyrotechnical process is difficult. We describe a new analytical approach for the identification of purified gold combining silver and copper isotopic with trace element analyses. Parting experiments were performed with gold-silver-copper alloys using the classical salt cementation process to investigate potential silver and copper isotope fractionation and changes in trace element concentrations. In addition, we provide the first comprehensive dataset of silver isotope ratios of archaeological gold objects from the Mediterranean and Central Europe to test whether or not gold refining can be identified on the basis of isotope systematics. The results show that very heavy silver and copper isotopic compositions are clear evidence for parted gold, but that the application of copper isotopes might be limited.

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