Isotope Analysis Research Articles

Biomolecular evidence reveals mares and long-distance imported horses sacrificed by the last pagans in temperate Europe.

Horse sacrifice and deposition are enigmatic features of funerary rituals identified across prehistoric Europe that persisted in the eastern Baltic. Genetic and isotopic analysis of horses in Balt cemeteries [1st to 13th centuries CE (Common Era)] dismantle prevailing narratives that locally procured stallions were exclusively selected. Strontium isotope analysis provides direct evidence for long-distance (~300 to 1500 kilometers) maritime transport of Fennoscandian horses to the eastern Baltic in the Late Viking Age (11th to 13th centuries CE). Genetic analysis proves that horses of both sexes were sacrificed with 34% identified as mares. Results transform the understanding of selection criteria, disprove sex-based selection, and elevate prestige value as a more crucial factor. These findings also provide evidence that the continued interaction between pagans and their newly Christianized neighbors sustained the performance of funerary horse sacrifice until the medieval transition. We also present a reference 87Sr/86Sr isoscape for the southeastern Baltic, releasing the potential of future mobility studies in the region.

Amplified seasonality in western Europe in a warmer world.

Documenting the seasonal temperature cycle constitutes an essential step toward mitigating risks associated with extreme weather events in a future warmer world. The mid-Piacenzian Warm Period (mPWP), 3.3 to 3.0 million years ago, featured global temperatures approximately 3°C above preindustrial levels. It represents an ideal period for directed paleoclimate reconstructions equivalent to model projections for 2100 under moderate Shared Socioeconomic Pathway SSP2-4.5. Here, seasonal clumped isotope analyses of fossil mollusk shells from the North Sea are presented to test Pliocene Model Intercomparison Project 2 outcomes. Joint data and model evidence reveals enhanced summer warming (+4.3° ± 1.0°C) compared to winter (+2.5° ± 1.5°C) during the mPWP, equivalent to SSP2-4.5 outcomes for future climate. We show that Arctic amplification of global warming weakens mid-latitude summer circulation while intensifying seasonal contrast in temperature and precipitation, leading to an increased risk of summer heat waves and other extreme weather events in Europe's future.

Sensitive 236U/238U Isotopic Analysis of Trace Uranium in Safeguards Environmental Samples Using Multicollector Inductively Coupled Plasma Mass Spectrometry.

A sensitive analytical technique was developed for determining a 10-7 level low 236U/238U ratio using multicollector inductively coupled plasma mass spectrometry. This analytical technique can determine the subnanogram amount of uranium in safeguards environmental samples. To increase the sensitivity of the 236U/238U ratio, (1) the feed solution was concentrated to one-tenth of that in the conventional method and (2) data acquisition was started from the beginning of the solution uptake until all of the solution was exhausted. All signal intensities were recorded. This technique was applied to the IRMM-184 uranium isotopic standard solution with a 1.2410 × 10-7 236U/238U ratio. The IRMM-184 uranium solution (0.2 mL of 1 ng g-1 uranium) was prepared, and the 236U/238U ratios were determined using our new data collection method. The 236U/238U ratios were in agreement with the certified value within the uncertainty (k = 2) evaluated using the Guide to the Expression of Uncertainty in Measurement (GUM) workbench. The uncertainties obtained with this new technique (32% on average) were revised to be 10 times smaller than those obtained with the conventional method using 0.1 ng g-1 IRMM-184. The tailing effect from the 238U intense peak was determined using 10 times higher concentrations of NBL CRM U0002 uranium isotopic standard solution (10 ng g-1 uranium) to improve its uncertainty. Approximately 1-2% of the uncertainties of 236U/238U could be further reduced using this improved correction factor.

Compound-Specific Isotope Analysis Provides Direct Evidence for Identifying the Source of Residual Pesticides Diazinon and Procymidone in the Soil-Plant System.

Compound-specific isotope analysis stands as a promising tool for unveiling the behavior of pesticides in agricultural environments. Using the commercial formulations of persistent fungicide procymidone (PRO) and less persistent insecticide diazinon (DIA), respectively, we analyzed the concentration and carbon isotope composition (δ13C) of the residual pesticides through soil incubation experiments in a greenhouse (for 150 days) and lab conditions (for 50-70 days). Our results showed that the magnitude of δ13C variation depends on pesticide specificity, in which PRO in the soil exhibited little variation in δ13C values over the entire incubation times, while DIA demonstrated an increased δ13C value, with the extent of δ13C variability affected by different spiking concentrations, plant presence, and light conditions. Moreover, the pesticides extracted from soils were isotopically overlapped with those from crop lettuce. Ultimately, the isotope composition of pesticides could infer the degradation and translocation processes and might contribute to identifying the source(s) of pesticide formulation in agricultural fields.

Fluid flow-driven multiphase dolomitization in the Cambrian Jutana Formation, salt range and adjacent area (Pakistan): insights from sedimentological and isotopic analyses

Fluid flow-driven multiphase dolomitization in the Cambrian Jutana Formation, salt range and adjacent area (Pakistan): insights from sedimentological and isotopic analyses

Actinide isotope analysis and trace element composition of bones of prehistoric animals and humans by inductively coupled plasma mass spectrometry (ICP-MS)

AbstractInductively coupled plasma mass spectrometry (ICP-MS) has been used for analysis of the bones of archanthropus, ancient bear, southern mammoths, dinosaurs, as well as soils collected in various parts of Uzbekistan. The concentrations of 64 elements have been detected including thorium and uranium for which isotope compositions were also analysed. The comparison of the ICP-MS data with the results we obtained earlier for some bones using instrumental neutron activation analysis (INAA) is presented. The concentrations of 234, 235, 238U are up to two orders of magnitude elevated compared to the soils (e.g.238U in south mammoth bone—130.1 mg/kg, and that of soil is only 1.6 mg/kg). The levels of 236U, and 239, 240, 242, 244Pu isotopes (possible neutron capture products of 235U and 238U) correspond to a count rate of blank samples. In addition, the isotope analysis confirms the uranium in the bones and surrounding soils is natural (the average determined for all samples uranium ratios 235U/238U = 0.0071 ± 0.0003 (2-sigma errors). The concentration of 230Th (which is the part of 234U and 238U decay chain) is also elevated in the bones compared to the surrounding soils, however, the concentrations of stable 232Th largely correspond to those of the soil. The excess uranium detected in bones is most probably due to the preferential accumulation from soil, and not to the paleo diet.

Diets, stress, and disease in the Etruscan society: Isotope analysis and infantile skeletal palaeopathology from Pontecagnano (Campania, southern Italy, 730-580 BCE).

Susceptibility to morbidity and mortality is increased in early life, yet proactive measures, such as breastfeeding and weaning practices, can be taken through specific investments from parents and wider society. The extent to which such biosocialcultural investment was achieved within 1st millennium BCE Etruscan society, of whom little written sources are available, is unkown. This research investigates life histories in non-adults and adults from Pontecagnano (southern Italy, 730-580 BCE) in order to track cross-sectional and longitudinal breastfeeding and weaning patterns and to characterize the diet more broadly. Stable carbon and nitrogen isotope analysis of incrementally-sampled deciduous and permanent dentine (n = 15), bulk bone collagen (n = 38), and tooth enamel bioapatite (n = 21) reveal the diet was largely based on C3 staple crops with marginal contributions of animal protein. Millet was found to play a role for maternal diet and trajectories of breastfeeding and feeding for some infants and children at the site. The combination of multiple isotope systems and tissues demonstrates exclusive breastfeeding was pursued until 0.6 years, followed by progressive introduction of proteanocius supplementary foods during weaning that lasted between approximately 0.7 and 2.6 years. The combination of biochemical data with macroscopic skeletal lesions of infantile metabolic diseases and physiological stress markers showed high δ15Ndentine in the months prior to death consistent with the isotopic pattern of opposing covariance.

Comparison of δ13C and δ15N of ecologically relevant amino acids among beluga whale tissues

Ecological applications of compound-specific stable isotope analysis (CSIA) of amino acids (AAs) include 1) tracking carbon pathways in food webs using essential AA (AAESS) δ13C values, and 2) estimating consumer trophic position (TP) by comparing relative differences of ‘trophic’ and ‘source’ AA δ15N values. Despite the significance of these applications, few studies have examined AA-specific SI patterns among tissues with different AA compositions and metabolism/turnover rates, which could cause differential drawdown of body AA pools and impart tissue-specific isotopic fractionation. To address this knowledge gap, especially in the absence of controlled diet studies examining this issue in captive marine mammals, we used a paired-sample design to compare δ13C and δ15N values of 11 AAs in commonly sampled tissues (skin, muscle, and dentine) from wild beluga whales (Delphinapterus leucas). δ13C of two AAs, glutamic acid/glutamine (Glx, a non-essential AA) and, notably, threonine (an essential AA), differed between skin and muscle. Furthermore, δ15N of three AAs (alanine, glycine, and proline) differed significantly among the three tissues, with glycine δ15N differences of approximately 10 ‰ among tissues supporting recent findings it is unsuitable as a source AA. Significant δ15N differences in AAs such as proline, a trophic AA used as an alternative to Glx in TP estimation, highlight tissue selection as a potential source of error in ecological applications of CSIA-AA. Amino acids that differed among tissues play key roles in metabolic pathways (e.g., ketogenic and gluconeogenic AAs), pointing to potential physiological applications of CSIA-AA in studies of free-ranging animals. These findings underscore the complexity of isotopic dynamics within tissues and emphasize the need for a nuanced approach when applying CSIA-AA in ecological research.

Position-specific carbon stable isotope analysis of glyphosate: isotope fingerprinting of molecules within a mixture.

Glyphosate [N-(phosphonomethyl) glycine] is a widely used herbicide and a molecule of interest in the environmental sciences, due to its global use in agriculture and its potential impact on ecosystems. This study presents the first position-specific carbon isotope (13C/12C) analyses of glyphosates from multiple sources. In contrast to traditional isotope ratio mass spectrometry (IRMS), position-specific analysis provides 13C/12C ratios at individual carbon atom positions within a molecule, rather than an average carbon isotope ratio across a mixture or a specific compound. In this work, glyphosate in commercial herbicides was analyzed with only minimal purification, using a nuclear magnetic resonance (NMR) spectroscopy method that detects 1H nuclei with bonds to either 13C or 12C, and isolates the signals of interest from other signals in the mixture. Results demonstrate that glyphosate from different sources can have significantly different intramolecular 13C/12C distributions, which were found to be spread over a wide range, with δ13C Vienna Peedee Belemnite (VPDB) values of -28.7 to -57.9‰. In each glyphosate, the carbon with a bond to the phosphorus atom was found to be depleted in 13C compared to the carbon at the C2 position, by 4 to 10‰. Aminomethylphosphonic acid (AMPA) was analyzed for method validation; AMPA contains only a single carbon position, so the 13C/12C results provided by the NMR method could be directly compared with traditional isotope ratio mass spectrometry. The glyphosate mixtures were also analyzed by IRMS to obtain their average 13C/12C ratios, for comparison with our position-specific results. This comparison revealed that the IRMS results significantly disguise the intramolecular isotope distribution. Finally, we introduce a 31P NMR method that can provide a position-specific 13C/12C ratio for carbon positions with a C-P chemical bond, and the results obtained by 1H and 31P for C3 carbon agree with one another within their analytical uncertainty. These analytical tools for position-specific carbon isotope analysis permit the isotopic fingerprinting of target molecules within a mixture, with potential applications in a range of fields, including the environmental sciences and chemical forensics.

Multi-isotope reconstruction of Late Pleistocene large-herbivore biogeography and mobility patterns in Central Europe

Interpretations of Late Pleistocene hominin adaptative capacities by archaeologists have focused heavily on their exploitation of certain prey and documented contemporary behaviours for these species. However, we cannot assume that animal prey-taxa ecology and ethology were the same in the past as in the present, or were constant over archaeological timescales. Sequential isotope analysis of herbivore teeth has emerged as a particularly powerful method of directly reconstructing diet, ecology and mobility patterns on sub-annual scales. Here, we apply 87Sr/86Sr isotope analysis, in combination with δ18O and δ13C isotope analysis, to sequentially sampled tooth enamel of prevalent herbivore species that populated Europe during the Last Glacial Period, including Rangifer tarandus, Equus sp. and Mammuthus primigenius. Our samples come from two open-air archaeological sites in Central Germany, Königsaue and Breitenbach, associated with Middle Palaeolithic and early Upper Palaeolithic cultures, respectively. We identify potential inter- and intra-species differences in range size and movement through time, contextualised through insights into diet and the wider environment. However, homogeneous bioavailable 87Sr/86Sr across large parts of the study region prevented the identification of specific migration routes. Finally, we discuss the possible influence of large-herbivore behaviour on hominin hunting decisions at the two sites.

Unravelling social status in the first medieval military order of the Iberian Peninsula using isotope analysis

Medieval Iberia witnessed the complex negotiation of religious, social, and economic identities, including the formation of religious orders that played a major role in border disputes and conflicts. While archival records provide insights into the compositions of these orders, there have been few direct dietary or osteoarchaeological studies to date. Here, we analysed 25 individuals discovered at the Zorita de los Canes Castle church cemetery, Guadalajara, Spain, where members of one of the first religious orders, the Order of Calatrava knights, were buried between the 12th to 15th centuries CE. Stable carbon (δ13C) and nitrogen (δ15N) isotope analyses of bone collagen reveal dietary patterns typical of the Medieval social elite, with the Bayesian R model, ‘Simmr’ suggesting a diet rich in poultry and marine fish in this inland population. Social comparisons and statistical analyses further support the idea that the order predominantly comprised the lower nobility and urban elite in agreement with historical sources. Our study suggests that while the cemetery primarily served the order's elite, the presence of individuals with diverse dietary patterns may indicate complexities of temporal use or wider social interaction of the medieval military order.

Population dynamics and paleoenvironmental inferences of Turonian planktonic foraminiferal assemblages from SE Tanzania and ODP Site 762 (Exmouth Plateau, eastern Indian Ocean)

Abstract The Tanzania Drilling Program (TDP) recovered hemipelagic sediments from land-based boreholes that yielded extraordinarily well-preserved, diverse Turonian foraminifera. Reliable oxygen and carbon isotopic analyses through most of the Turonian Stage and biostratigraphic data were documented. This study compares Turonian foraminiferal population dynamics and associated geochemical proxy records among the TDP boreholes with correlative records from Ocean Drilling Program Site 762 (Exmouth Plateau, eastern Indian Ocean). The two regions were separated by ∼12° latitude and ∼5,000 km of ocean with the Indian continental plate located between. Taxonomic turnover is similar is nearly simultaneous in both regions across the transition from the Helvetoglobotruncana helvetica Zone to the Falsotruncana maslakovae Zone (∼93.0 Ma). Changes include overlapping extinctions of all helvetoglobotruncanids, most dicarinellids and one species of Praeglobotruncana and subsequent first appearances of marginotruncanid and falsotruncanid species. Increased abundance of biserial planktonic foraminifera is recorded at multiple TDP sites and at Site 762 across the contact of the Fa. maslakovae and Huberella huberi Zone about 0.5 m.y. after the Hv. helvetica / Fa. maslakovae transition. Geochemical records at the two sites do not indicate associated paleoenvironmental changes in surface water conditions that would explain coordinated changes in species composition on opposites sides of the Indian Ocean.

Division of the Early Proterozoic Khargitui Formation of the Sarma Group (Akitkan Orogenic Belt, Siberian Craton) into Different Age Sequences Based on the Results of U–Pb Isotopic Analysis of Zircon

Division of the Early Proterozoic Khargitui Formation of the Sarma Group (Akitkan Orogenic Belt, Siberian Craton) into Different Age Sequences Based on the Results of U–Pb Isotopic Analysis of Zircon

Continuous-Flow Stable Sulfur Isotope Analysis of Organic and Inorganic Compounds by EA-MC-ICPMS.

Elemental analysis (EA) coupled to isotope ratio mass spectrometry (IRMS) is a well-established method to derive stable isotope ratios of sulfur (34S/32S). Conversion of sulfur to SO2 by EA and measurement of SO2 isotopologues by IRMS represents the simplest and most versatile method to accomplish isotope measurement of sulfur even in bulk samples. Yet, interferences by oxygen isotopes in SO2 often impair the precision and trueness of measured results. In the current study, we coupled EA to multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) to establish a method that avoids such interferences due to direct measurement of S+ ions. In addition, measurement of the 33S/32S isotope ratios is possible, thus representing the first bulk method that is suitable to study mass-independent isotope fractionation (MIF). Analytical precision (σ) of available Ag2S and BaSO4 reference materials (RMs) was, on average, 0.2 mUr for δ33S and δ34S, never exceeding 0.3 mUr within this study (1 mUr = 1‰ = 0.001). Measured δ34S values of reference materials agreed within ±0.2 mUr of officially reported values. Measurement of wood samples yielded good precision (0.2 mUr) for sulfur amounts as low as 3.5 μg, but precision deteriorated for samples at lower sulfur contents due to poor peak shape. Finally, we explored cross-calibration of organic liquids separated via gas chromatography (GC) against solid RMs combusted via EA that avoids challenging offline conversion of RMs. Results indicate good precision (≤0.08 mUr) and acceptable trueness (≤0.34 mUr) for determination of δ34S, demonstrating the future potential of such an approach.

Food-web construction and ecological effects of implementing non-traditional biomanipulation in eutrophic reservoirs in North-central China

ABSTRACT This study was undertaken to elucidate the food web structure and interspecific interactions in the lakes and reservoirs undergoing eutrophication and to assess the efficacy of lake-wide non-traditional biomanipulation (direct predation of cyanobacteria by proliferating planktivorous fish) for bloom management. Analyses of aquatic organisms and stable isotopes of basic food sources and consumers were performed for Zhangze Reservoir in North-central China. Additionally, an improved scheme based on plankton changes and interspecific interactions is proposed on this basis. Compared with other widely-studied eutrophic reservoirs, the δ 15N value of each component of the food web in Zhangze Reservoir was higher, the food chain was relatively long and the δ 13C range of fish consumers was narrower. Planktivorous fish consumed phytoplankton as their primary food source. However, the phytoplankton biomass and the percentage of cyanobacteria increased, and eutrophication did not improve. The findings concerning the composition of consumers and their food sources in Zhangze Reservoir indicate the urgent need to change the fish structure to optimise the structure of plankton community and mitigate phytoplankton overgrowth. The study findings provide a basis for the implementation of effective eutrophication management strategies in lakes and reservoirs where planktivorous fish are prevalent.

Assessing Diet & Trophic Position of Fish in Chenderoh Reservoir, Malaysia: SCA & SIA Approach

The present study assessed and compared the diet and trophic positions (TP) of two carnivorous fish H. macrolepidota and C. ocellaris from Chenderoh Reservoir, Malaysia. The focal goal of the study was to understand the effects of invasive non-indigenous species (NIS), C. ocellaris, on the native indigenous (IS) fish species, H. macrolepidota. Data were acquired from September 2014 to February 2015 within the study area. The assessment was grounded in stomach content analysis (SCA) and stable isotope analysis (SIA), which collectively clarified the feeding habits and trophic positions (TP) of these selected fish. In total, 184 fish samples (comprising 64 individuals of H. macrolepidota and 120 individuals of C. ocellaris) underwent stomach content analysis (SCA). Additionally, 24 individuals (12 of H. macrolepidota and 12 of C. ocellaris), sampled from December 2014 to February 2015, were selected for stable isotope analysis (SIA). The mean RGL values for H. macrolepidota and C ocellaris were 0.98 ± 0.18 and 1.10 ± 0.15 (Mean ± SD), respectively, aligning with known ranges for carnivorous fish. These values also clarified that both species occupy higher TP in the food web as tertiary or quaternary consumers. SCA findings also revealed that fish and crustaceans were the predominant food categories for H. macrolepidota, while C. ocellaris predominantly fed on fish. The mean stomach fullness index (MSF) and the gastrosomatic index (GSI) corroborated the differences in the foraging performance of the fishes, with C. ocellaris having a higher MSF (2.03) compared to H. macrolepidota (0.65). These implied that C. ocellaris had plentiful of food and encountered fewer diet-related challenges in the ecosystem. From SIA, δ13C values indicated that the primary carbon sources for both species are C3 plants, particularly aquatic vegetation. Further, δ15N values further ensured that both H. macrolepidota and C. ocellaris are carnivorous in nature and occupy higher TP in the ecosystem.

Late-fracture calcite veins decode natural gas preservation

The preservation of natural gas can be easily dismissed by late crustal deformations, which are often concealed by fracture-filling calcite vein networks. This study introduces a novel approach to confine the timeframe of natural gas-leakage processes by employing coupled in situ U–Pb dating and clumped isotope (Δ47) analysis of late-fracture calcite veins associated with brittle deformation in caprock/unconventional reservoirs during basin uplift. Specifically, Δ47 and U–Pb data were acquired for fracture calcite veins that formed in high-angle or vertical fractures within the early Silurian shale reservoirs of the Southeastern Sichuan Basin in China. Absolute U–Pb ages revealed two distinct calcite precipitation events at 6.89 ± 0.18 and 3.55 ± 0.11 Ma, respectively. The primary mechanism for shale gas escape from early Silurian shale reservoirs was the leakage of natural gas through activated high-angle faults that had remained unsealed since at least 6.89 Ma. At approximately 3.55 Ma, the overlying weathered layer was lifted to the surface of the Earth, facilitating the connection between meteoric water and shale reservoirs through activated fractures. Natural gas leakage occurred concurrently with meteoric water infiltration, and a non-linear mixing effect between methanogenesis and meteoric water, as well as intense ventilation along the water-bearing fracture surface, is identified as the cause of delayed late-fracture calcite precipitation, leading to an abnormal δ13C of calcite vein (up to +22.1‰). This approach holds significant implications for assessing natural-gas preservation in uplifted basins worldwide.

Life histories in Fiji as reconstructed from first millennium CE Sigatoka Sand Dune burials using isotopes

This paper aims to re-examine the dietary practices of individuals buried at Sigatoka Sand Dunes site (Fiji) in Burial Ground 1 excavated by Simon Best in 1987 and 1988 using two approaches and a reassessment of their archaeological, bioarchaeological and chronological frame. First, stable carbon and nitrogen isotope analysis was applied to document dietary changes between childhood and adulthood using an intra–individual approach on paired bone–tooth. Second, the potential adaptation of the individuals to their environment was evaluated through regional and temporal comparisons using inter–individual bone analysis. Ten AMS radiocarbon dates were measured directly on human bone collagen samples, placing the series in a range of approximately 600 years covering the middle of the first millennium CE (1,888 to 1,272 cal BP). δ13C and δ15N ratios were measured on bone and tooth collagen samples from 38 adult individuals. The results show that δ15N values from tooth are higher than those s from bone while bone and tooth δ13C values are similar, except for females. Fifteen individuals were included in an intra–individual analysis based on paired bone and tooth samples, which revealed six dietary patterns distinguished by a differential dietary intake of marine resources and resources at different trophic levels. These highlight sex–specific differences not related to mortuary practices but to daily life activities, supporting the hypothesis of a sexual division of labour. Compared to other Southwest Pacific series, Sigatoka diets show a specific trend towards marine food consumption that supports the hypothesis of a relative food self–sufficiency requiring no interactions with other groups.

Uranium Single Particle Analysis for Simultaneous Fluorine and Uranium Isotopic Determinations via Laser-Induced Breakdown Spectroscopy/Laser Ablation-Multicollector-Inductively Coupled Plasma-Mass Spectrometry.

Uranyl fluoride (UO2F2) particles (<20 μm) were subjected to first-of-its-kind analysis via simultaneous laser-induced breakdown spectroscopy (LIBS) and laser ablation multi-collector inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS). Briefly, a nanosecond pulsed high-energy laser was focused onto the sample (particle) surface. In a single laser pulse, the UO2F2 particle was excited/ionized within the microplasma volume, and the emission of light was collected via fiber optics such that emission spectroscopy could be employed for the detection of uranium (U) and fluorine (F). The ablated particle was simultaneously transported into the MC-ICP-MS for high precision isotopic (i.e., 234U, 235U, and 238U) analysis. This method, LIBS/LA-MC-ICP-MS was optimized and employed to rapidly measure 80+ UO2F2 particles, which were subjected to different calcination processes, which results in varying degrees of F loss from the individual particles. In measuring the particles, the average F/U ratios for the populations treated at 100 and 500 °C were 2.78 ± 1.28 and 1.01 ± 0.50, respectively, confirming loss of F through the calcination process. The average 235U/238U on the particle populations for the 100 and 500 °C were 0.007262 (22) and 0.007231 (23), which was determined to be <0.2% from the expected value. The 234U/238U ratios on the same particles were 0.000053 (11) and 0.000050 (10) for the 100 and 500 °C, respectively, <10% from the expected value. Notably, each population was analyzed in under 5 min, demonstrating the truly rapid analysis technique presented here.

Geology and Geochronology of Magmatic–Hydrothermal Breccia Pipes in the Yixingzhai Gold Deposit: Implications for Ore Genesis and Regional Exploration

Magmatic–hydrothermal breccia pipes are widespread in numerous major porphyry and epithermal gold deposits globally, representing significant repositories of metal resources and serving as potential indicators for exploration targeting. More than ten breccia pipes occur in the Central Taihangshan District (CTD) of the North China Craton. Some of these breccia pipes host gold mineralization and are proposed to be related to the adjacent lode gold mineralization. However, the lack of detailed geological constraints make this hypothesis ambiguous. To address this, the present study conducted comprehensive field observations, drill core logging, an in situ sulfur isotope analysis of pyrite, and the 40Ar/39Ar dating of adularia along a 1400 m section of the Tietangdong breccia pipe at Yixingzhai. Three distinct breccia facies were identified at Tietangdong, exhibiting variable proportions across the entire section, including a massive skarn breccia; polymictic, skarn matrix-supported breccia; and polymictic, intrusive rock cement chaotic breccia. Furthermore, adularia 40Ar/39Ar dating indicates a syn-/post-gold mineralization age of 136 ± 1.5 Ma, coinciding with the age of post-breccia felsite dike. The deepest sampled pyrite displays δ34S values of ~2.7‰, strongly indicating a magmatic–hydrothermal signature. These results, when combined with the geological, geochronological, and isotopic studies on the adjacent lode gold mineralization, further suggest a close genetic relationship between the breccia pipes and the lode Au mineralization, paving the way for their utilization as effective indicators for gold targeting within the CTD.