Abstract Social anthropology and ethnographic studies have described kinship systems and networks of contact and exchange in extant populations 1–4 . 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 ‘les Noisats’ (France), dated to the western European Neolithic around 4850–4500 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.
A new algorithm is proposed that uses Pb isotopes to help identify the ore deposits utilized as sources of silver in Antiquity. The algorithm takes natural and analytical isotope fractionation into account. It proposes a statistical measure of the distances between the Pb isotope compositions of ores and artifacts. This measure is amenable to statistical tests at any confidence level. The new algorithm is applied to the Pb isotope compositions of the end-members derived from 368 new Pb isotope data on silver coinage minted between the late 6th to late 2nd centuries BCE and presented in Albarede et al. (2024). The algorithm identifies the local sources expected for the mints associated with major silver ores found in the territories of Athens, Thasos, and Thrace, while demonstrating that Thrace, Northern Macedonia, and Chalkidiki supplied notable amounts of bullion to Aegina and Ptolemaic Egypt. Minor proportions of what we are designating an old Sardinian 'mix' created by long-distance trade was used by archaic Athens, Corinthia (Corinth and surrounding city-states), and Aegina. Various islands in the Cyclades (Siphnos, Keos, Seriphos) also appear to be early contributors to archaic Corinthian and Macedonian silver. The present study clearly demonstrates that recycled and mixed bullion formed a substantial part of the silver stocks of mints. The new algorithm warrants more detailed Pb isotopic studies of well-dated coinage to document the changing nature of silver fluxes over time.
In an attempt to clarify the significance of Pb model ages in Pb-Zn sedimentary deposits, we report high-precision Pb isotopic compositions for 64 galenas and 52 K-feldspars, the former from ores and the latter separated from granites. All samples are from Spain and the French Pyrenees. Lead from galena ores is of unequivocal continental origin. With few exceptions, Pb model ages systematically exceed emplacement ages by up to 400 Ma, a gap which is well outside the uncertainties of ~ 30 Ma assigned to the model. The histogram of the new high-precision Pb isotope data shows prominent peaks of galena Pb model ages at 94 ± 38 Ma and 392 ± 39 Ma. When the data are consolidated with literature data and examined in 3-dimensional Pb isotope space, cluster analysis identifies five groups. The model ages of the peaks occur, in order of decreasing peak intensity, at 395 ± 40 (Middle Devonian), 90 ± 34 Ma (Middle Cretaceous), and 613 ± 42 Ma (Neoproterozoic), with two minor peaks at 185 + 26 Ma (Jurassic) and 313 ± 41 (Upper Carboniferous). To a large extent, the model ages centered around these peaks correspond to distinct localities. The ages of the peaks do not coincide with any of the Betic, Variscan, or Pan-African tectonic events, which are the main tectonic episodes that shaped Iberian geology, but instead match well-known global oceanic anoxic events. It is argued that surges of metals weathered from continental surfaces scorched during anoxic events accumulated and combined in anoxic water masses with unoxidized marine sulfide released by submarine hydrothermal activity to precipitate the primary Pb-Zn stock. Frozen Pb isotope compositions require that galenas from black shales are the source of the final ores. The sulfides were later remobilized by large-scale convective circulation of basinal and hydrothermal fluids. The peaks of K-feldspar Pb model ages are distinct from those of galenas and do not correlate with magmatic emplacement ages. It is suggested that they instead reflect local circulation in Paleozoic sediments surrounding individual plutons. While Pb isotopes can be used as a regional provenance tool, such an approach requires that the data are considered in a fully 3-dimensional space.
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.
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Abstract Silver played a key role in the progressive monetization of early Mediterranean civilizations. We combine Pb and Ag isotopes with volatile trace elements (Bi, Sb, and As) to assess whether, during the Roman occupation of Iberia, galena constituted a significant source of silver. We find that the Pb and Ag isotopic compositions of 47 samples of galena from eight different Iberian mining provinces, many of them exploited during Roman times, are uncorrelated. This indicates that their respective isotopic variabilities depend on different petrogenetic processes. Moreover, the range of Ag isotopic abundances is approximately six times wider than that displayed worldwide by silver coins in general and Roman silver coins in particular. Although galena from the Betics provides the best fit for Pb isotopes with Roman coins, their fit with Ag isotopic compositions is at best sporadic. We suggest that, together with Sb, Bi, and As, silver is primarily derived from fluids boiled off from differentiated mantle-derived magmas. These fluids, in turn, reacted with preexisting galena and functioned as a silver trap. Lead sulfides with ε109Ag of ~0 and unusually rich in Ag, Sb, Bi, and As were the most probable sources of ancient silver, whereas samples with ε109Ag departing significantly from ~0 reflect low-temperature isotopic fractionation processes in the upper crust.
Abstract Thalattosuchians are crocodylomorphs mainly known from marine strata of Early Jurassic to Early Cretaceous age. They represent the earliest crocodylomorph radiation to an aquatic habitat and their evolutionary history offers very few records from freshwater settings. Here, we report several exquisitely preserved thalattosuchian skulls attributed to a derived teleosaurid from a pedogenic horizon located at the base of a fluvial series of alternating silts and sandstones of the Phu Kradung Formation (Upper Jurassic) of northeastern Thailand. Using laser ablation multicollector inductively coupled mass spectrometry (MC-ICP-MS) on tooth enamel and dentine, we measured isotopic ratios of strontium ( 87 Sr/ 86 Sr) to test the habitat of these teleosaurids. In addition, Sr concentrations of the dental tissues were estimated from the calibrated signal intensities of the Sr isotope measurements. The dataset includes bioapatite (teeth or scales) of eight terrestrial and five aquatic vertebrates. Theropods exhibit lower Sr concentrations both in enamel and dentine compared to others groups, a pattern in accordance with the calcium biopurification process, which predicts that Sr concentrations in the body of vertebrates decrease up the trophic chain. It also excludes the possibility that diagenesis has completely overprinted the Sr isotope compositions of the fossil assemblage, which exhibits a homogeneous 87 Sr/ 86 Sr signature above the Late Jurassic seawater value. Values for teleosaurid teeth are in the range of other values for vertebrates in the continental assemblage and imply that these crocodylomorphs did not migrate between freshwater and marine habitats at least in the time constraint of the mineralizing tooth. This result represents the first demonstration that a population of teleosaurids was established for a prolonged time in a freshwater environment. Whether the ability of teleosaurids to inhabit freshwater habitats is a secondary adaptation or whether it is plesiomorphic and inherited from freshwater ancestors is discussed.
Was silver coinage minted from fresh metal newly extracted from the mine or was it from recycled silver deriving from older coins, silverware, or cult objects? The answer helps understand the provenance of coins and their circulation. Using Pb isotopes, the present work proposes a method to disentangle the sources of 368 silver-alloy coins from Athens, Corinth, Aegina, Thasos, Thrace, Macedonia, and Ptolemaic Egypt. We outline a new mixing model based on Principal Component Analysis and allowing for multiple steps of bullion recycling. The first component accounts for 94–99% (typically 97–99%) of the total variance, which indicates that the data form a well-defined alignment indicative of a nearly binary mixture between two source ores referred to as 'end-members'. Isotopic evidence establishes the subordinate but pervasive practice of remelting. The strong skewness of the first principal component distribution shows that lead is dominated by the binary mixing of end-members. The geologically young end-member has high 206Pb/204Pb and is best exemplified by Laurion ore used in Athenian coinage. With the possible exception of Ptolemaic samples, the second end-member attests to the persistence of a low-206Pb/204Pb, geologically much older, end-member. In most cases, the distributions of a further two principal components are nearly symmetric and can be considered normal. If they represent ore sources, their very small contribution to the total variance qualifies them as 'noise' (caused by random isotopic fluctuations in the ores and analytical issues). We find that the Pb isotope ratios in the coinage issued by each minting authority are distributed as a power law. The slope of this distribution varies from one mint to another, with the steepest slopes (Corinth and Ptolemaic Egypt) indicating the predominance of freshly mined silver. The shallow slope of Macedonia demands a larger proportion of geologically old Pb. Silver supplied to the mint of Athens shifted from a mixture of high- and low-206Pb/204Pb in the late 6th c. BCE to a predominance of unmixed high-206Pb/204Pb ore from the mines of Laurion thereafter and fell back to a mixture with intermediate Pb isotope compositions in the second half of the 4th c. BCE. The limitation of the present study resides in the relatively small number of Pb isotope data for each mint, which, in most cases, prevents a statistically significant analysis of these data by periods. Nevertheless, the quasi-binary nature of most silver mixes stands out as a new and strong first-order, albeit somewhat counterintuitive, inference from the present data.
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