37 research outputs found
Inferring odontocete life history traits in dentine using a multiproxy approach (ÎŽ15N, ÎŽ44/42Ca and trace elements)
Funding Information: The authors thank F. Demaret and W. Dabin (Observatoire Pelagis) for helping secure odontocete milk and tooth samples. This work was funded by the Conseil National de la Recherche Scientifique (CNRS) INSU INTERRVIE program (Early Whale Resource Use and Diet project) to J.E.M. The authors thank LGLTPE (UMR 5276) and ENS de Lyon for supporting the MCâICP mass spectrometry platform. Nitrogen isotope measurements were performed on the âEcologie Isotopiqueâ platform of LEHNA (UMR 5023). The authors thank F. ArnauldâGodet and E. Albalat for technical support on the MCâICP platform of the LGLTPE. The authors thank the anonymous reviewers and the editor R. Bol for their constructive comments that helped improve the quality of this work. Funding Information: The authors thank F. Demaret and W. Dabin (Observatoire Pelagis) for helping secure odontocete milk and tooth samples. This work was funded by the Conseil National de la Recherche Scientifique (CNRS) INSU INTERRVIE program (Early Whale Resource Use and Diet project) to J.E.M. The authors thank LGLTPE (UMR 5276) and ENS de Lyon for supporting the MC-ICP mass spectrometry platform. Nitrogen isotope measurements were performed on the âEcologie Isotopiqueâ platform of LEHNA (UMR 5023). The authors thank F. Arnauld-Godet and E. Albalat for technical support on the MC-ICP platform of the LGLTPE. The authors thank the anonymous reviewers and the editor R. Bol for their constructive comments that helped improve the quality of this work. Publisher Copyright: © 2023 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.Peer reviewedPublisher PD
Lead isotopes as tracers of crude oil migration within deep crustal fluid systems
Although Pb, U, and Th may be fractionated between crude oil and formation waters, Pb isotopes are not. This unique property makes Pb isotopes a particularly useful marker of hydrocarbon generation and migration. Here we show that Pb isotopes offer a new vision of long-range (secondary) oil migration relevant to the formation of oil fields. North Sea oils are largely generated from Jurassic black shales, yet their Pb isotopes are mixtures of Cenozoic to Proterozoic end-members. The same observation is made for crude oils from the Paris Basin, the Barents Sea, Libya, Kuwait, Kazakhstan, and Australia. Bulk Pb in crude oil therefore, for the most part, is foreign to its source rock(s). Our high-precision Pb isotope data on 195 crude oils worldwide, the first such data set in the published literature, and 17 Northern European black shales indicate that deep-seated Pb components originating beneath the source rocks are ubiquitous in crude oil. This implies that oil fields are embedded in basinal convective systems of hydrous fluids heated from below. Plumes of hot fluids rise from the lower thermal boundary layer, which Pb isotopes require douse the basement, into the core of the porous-flow convective cell where they dissolve the newly formed hydrocarbons sequestered in the source rocks. The fluids finally unload unmixed formation waters and crude oil at the base of the upper (conductive) boundary layer where they can be trapped in favorable sites. Based on these new insights we argue that Pb isotopes in crude oil constitute a good tracer of oil migration
InfĂ©rences sur les rĂ©seaux rĂ©gionaux Ă partir dâarbres gĂ©nĂ©tiques locaux, lâexemple du site nĂ©olithique de Gurgy 'les Noisats'
La reconstitution de la parentĂ© gĂ©nĂ©tique dans des contextes archĂ©ologiques a longtemps Ă©tĂ© impossible, mais grĂące Ă lâoptimisation rĂ©cente des mĂ©thodes dâanalyse de lâADN ancien, on peut dĂ©sormais reconstituer de maniĂšre fiable des gĂ©nĂ©alogies gĂ©nĂ©tiques, parfois importantes. Lâanalyse gĂ©nomique approfondie du site français du NĂ©olithique moyen de Gurgy 'les Noisats', dans le Bassin parisien, nous a permis de reconstruire deux arbres consĂ©quents, lâun reliant 63 individus sur sept gĂ©nĂ©ratio..
Extensive pedigrees reveal the social organization of a Neolithic community
Social anthropology and ethnographic studies have described kinship systems and networks of contact and exchange in extant populations 1â4. However, for prehistoric societies, these systems can be studied only indirectly from biological and cultural remains. Stable isotope data, sex and age at death can provide insights into the demographic structure of a burial community and identify local versus non-local childhood signatures, archaeogenetic data can reconstruct the biological relationships between individuals, which enables the reconstruction of pedigrees, and combined evidence informs on kinship practices and residence patterns in prehistoric societies. Here we report ancient DNA, strontium isotope and contextual data from more than 100 individuals from the site Gurgy âles Noisatsâ (France), dated to the western European Neolithic around 4850â4500 bc. We find that this burial community was genetically connected by two main pedigrees, spanning seven generations, that were patrilocal and patrilineal, with evidence for female exogamy and exchange with genetically close neighbouring groups. The microdemographic structure of individuals linked and unlinked to the pedigrees reveals additional information about the social structure, living conditions and site occupation. The absence of half-siblings and the high number of adult full siblings suggest that there were stable health conditions and a supportive social network, facilitating high fertility and low mortality 5. Age-structure differences and strontium isotope results by generation indicate that the site was used for just a few decades, providing new insights into shifting sedentary farming practices during the European Neolithic
Platinum-group elements and gold in silver coinage and the issue of salt cementation
International audienceIt has been proposed that gold purification by cementation could account for the low gold content of ancient Greek coinage from Attica and the Cyclades. In order to place new constraints on this suggestion, the concentrations of platinum-group elements (PGEs) and gold have been measured in 72 silver coins mostly from the Greek Archaic and Classical periods, but also from Rome, India, medieval Europe, and colonial Spanish Americas, by inductively coupled plasma mass spectrometry. A novel technique allowing these concentrations to be determined in silver coins is described. Variations are consistent with element position in the periodic table. The volatile elements Rh and Os are commonly at or below the detection level, which may reflect evaporation during smelting and cupellation. Ruthenium and Ir, which binary phase equilibrium experiments show to be insoluble in solid silver and gold, and soluble Pd and Pt, show variations in coinage consistent with these properties. The dichotomy of Ir/Au ratios is not consistent with Ir loss in gold during salt cementation (parting) and is better explained by the contrast between Au-rich and Au-poor ore districts. This contrast is suggested to reflect either regional differences or the variability of conditions during ore genesis, such as hydrothermal solution chlorinity
Performance of the double-Wien filter of the Neoma MC-ICPMS/MS with an application to copper stable isotope compositions
The new Neoma MC-ICPMS/MS is equipped with a prefiltering system consisting of a double-Wien filter and a collision/reaction cell whose performances are challenged using different combinations of magnetic and electrostatic field values and adjustable slit apertures
Survival of lithium isotopic heterogeneities in the mantle supported by HIMU-lavas from Rurutu Island, Austral Chain.
International audienceThirty years ago, Hofmann and Hart [Hofmann, A.W., Hart, S.R., 1978. An assessment of local and regional isotopic equilibrium in the mantle, Earth Planet Sci. Lett. 38, 44â62] showed that local disequilibria of slowly diffusing radiogenic tracers (e.g. Sr) are preserved in the mantle over 1â2 Ga time scales. Recently, it was suggested that this is not the case for fast diffusing elements such as lithium [Halama, R., McDonough, W.F., Rudnick, R.L., Bell, K., 2008. Tracking the lithium isotopic evolution of the mantle using carbonatites, Earth Planet Sci. Lett. 265, 726â742], thus questioning the ability of lithium isotopes to constrain long-term effects of recycling of material with crustal signatures. A key issue in this debate is the identification in hotspot volcanism of Li isotopic fingerprint consistent with recycling. Previous studies proposed that HIMU type volcanism, which is thought to sample mantle domains that include subducted altered oceanic crust, has 7Li/6Li distinctively higher than the fresh mid-ocean ridge basalts. This work focuses on Rurutu island, where both HIMU (20.88 < 206Pb/204Pb < 21.42) and non-HIMU (19.11 < 206Pb/204Pb < 20.45) lavas occur. When considering only the freshest and most primitive lavas, the lithium isotopic signatures of HIMU (+ 5.4 < ÎŽ7Li < + 7.9â°) and non-HIMU (+ 2.9 < ÎŽ7Li < + 4.8â°) lavas do not overlap, thus supporting the idea that HIMU mantle has distinctly elevated ÎŽ7Li. This result suggests that Li isotopic heterogeneities could survive diffusion over 1â2 billion years, the amount of time required to develop the highly radiogenic Pb signature of HIMU-lavas. Modeling lithium diffusion out of a lithium-rich, isotopically heavy altered oceanic crust reveals that isotopic disequilibrium persists over long time periods in comparison with the rapid decrease of chemical disequilibrium. For instance, a kilometer-thick altered oceanic crust loses most of its Li excess in a matter of a few tens of millions of years but could preserve 7Li/6Li distinctively higher than the ambient mantle over a time period in excess of 1.5 Ga. After 1.5 Ga, a kilometer-thick altered oceanic crust has heavy but uniform 7Li/6Li, while large isotopic variations persist in the nearby mantle (< 20 km). Thus, decoupling between Li and slowly diffusing radiogenic isotopes can be predicted in the mantle nearby subducted crust