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Non-matrix-matched calibration of laser ablation ICPMS (trace/major) element data is a common quantification strategy. However, LA sampling is associated with downhole elemental fractionation, potentially causing inaccuracies if the magnitude of fractionation between the sample and reference material (RM) differs. Here, we estimate fractionation factors (FFs) for different elements (El) in a range of RMs relative to NIST SRM610/612 (FFEl/Ca-NIST) and evaluate element-specific corrections for downhole fractionation using these measured FFEl/Ca-NIST. Significantly different mean El/Ca values were observed before and after correction, particularly for the alkali elements (all RMs), and B, Fe, and Zn (some RMs), notably improving accuracy, especially for the alkali elements. In cases where this methodology does not result in an accuracy improvement, this may help identify underlying issues in reported/reference values for RMs, given that this phenomenon should be accounted for. Overall, we recommend considering routine assessment of FFs and applying a FF correction to enhance data quality. [ABSTRACT FROM AUTHOR]

We present the results of a multi-disciplinary investigation on a deciduous human tooth (Pradis 1), recently recovered from the Epigravettian layers of the Grotte di Pradis archaeological site (Northeastern Italian Prealps). Pradis 1 is an exfoliated deciduous molar (Rdm2), lost during life by an 11–12-year-old child. A direct radiocarbon date provided an age of 13,088–12,897 cal BP (95% probability, IntCal20). Amelogenin peptides extracted from tooth enamel and analysed through LC–MS/MS indicate that Pradis 1 likely belonged to a male. Time-resolved 87Sr/86Sr analyses by laser ablation mass spectrometry (LA-MC-ICPMS), combined with dental histology, were able to resolve his movements during the first year of life (i.e. the enamel mineralization interval). Specifically, the Sr isotope ratio of the tooth enamel differs from the local baseline value, suggesting that the child likely spent his first year of life far from Grotte di Pradis. Sr isotopes are also suggestive of a cyclical/seasonal mobility pattern exploited by the Epigravettian human group. The exploitation of Grotte di Pradis on a seasonal, i.e. summer, basis is also indicated by the faunal spectra. Indeed, the nearly 100% occurrence of marmot remains in the entire archaeozoological collection indicates the use of Pradis as a specialized marmot hunting or butchering site. This work represents the first direct assessment of sub-annual movements observed in an Epigravettian hunter-gatherer group from Northern Italy. [ABSTRACT FROM AUTHOR]

Knowledge of the boron isotopic composition of natural samples has found wide ranging application in both low and high temperature geochemistry. More recently, the development of boron isotope measurements using highly spatially-resolved analytical techniques is of interest as it is increasingly recognised that many materials are heterogeneous with respect to their boron isotopic composition, and moreover, that this heterogeneity yields valuable information about the environment of formation and/or mechanisms of crystallisation. Here, we build on a recently proposed methodology (Standish et al. [2019] Rapid Commun. Mass Spectrom.33:959) which enables precise and accurate δ11B measurement via LA-MC-ICPMS by accounting for a scattered Ca interference primarily on 10B. We propose minor modifications to this method via the use of 1013 Ω preamplifiers on the Faraday cup of the detector, more precise measurement of the Ca interference, and improved modelling of the shape of this interference correction. This yields single laser spot 2SE precision of ∼0.5‰ with a 70 μm beam (∼7 pg B), ∼1.4‰ with a 40 μm beam (∼2 pg B), and a long-term (1.5 year) intermediate precision in a marble standard with 15 μg g−1 [B] of <0.9‰ (2SD). Thus, spatially-resolved information comparable to that achievable via SIMS is possible. Moreover, we show theoretically and empirically that the inaccuracy predominantly resulting from a scattered Ca interference on 10B is also an issue for non-CaCO3 matrices, despite their typically lower [Ca]. Encouragingly, building multi-standard calibration lines to correct for this interference is also a way forward for silicate glasses, and we demonstrate accurate and precise (<0.5‰ 2SE) measurement of a basaltic glass with 3 μg g−1 [B] using a 74 μm diameter laser beam (<1 pg B). This paves the way forward for accurate and precise spatially-resolved δ11B measurement of a diverse range of sample matrices using laser ablation as a sample introduction system for MC-ICPMS instruments that are characterised by a scattered Ca interference in the region of m/z 10–11. [ABSTRACT FROM AUTHOR]

LA‐ICP‐MS is increasingly applied to obtain quantitative multi‐element data with minimal sample preparation, usually achieved by calibration using reference materials (RMs). However, some ubiquitous RMs, for example the NIST SRM 61× series glasses, suffer from reported value uncertainties for certain elements. Moreover, no long‐term data set of analyses conducted over a range of ablation and tuning conditions exists. Thus, there has been little rigorous examination of the extent to which offsets between measured and reported values are the result of error in these values rather than analytically induced fractionation. We present new software (‘LA‐MINE’), capable of extracting LA‐ICP‐MS data with no user input, and apply this to our system, yielding over 5 years of data (~ 5700 analyses of ten glass and carbonate RMs). We examine the relative importance of systematic analytical bias and possible error in reported values through a mass‐specific breakdown of fourteen of the most commonly determined elements. Furthermore, these data, obtained under a wide range of different ablation conditions, enable specific recommendations of how data quality may be improved, for example the role of diatomic gas, the effect of differential inter‐glass fractionation factors and choice of transport tubing material. Finally, these data demonstrate that the two‐volume Laurin ablation cell is characterised by no discernible spatial heterogeneity in measured trace element ratios. [ABSTRACT FROM AUTHOR]

We present a novel approach for ultra-high resolution laser-ablation inductively-coupled-plasma mass spectrometry (LA-ICPMS) analysis, which not only allows us to clearly resolve < 10 μm (daily) compositional variability in B/Ca, Mg/Ca, Sr/Ca and Ba/Ca, but also to detect long-term tidal and seasonal cycles in both Miocene and modern Tridacna (giant clam) shells. Daily element/Ca variability preserved within microscopically visible growth increments is resolved by utilizing the combined capabilities of a rotating rectangular aperture (spot size on target 4 × 50 μm), the rapid signal washout of a Laurin two-volume laser ablation cell and slow compositional profiling (≤ 1.5 μm/s). Striking co-variation between oscillating cycles in B/Ca, Mg/Ca, Sr/Ca and Ba/Ca is discernible, yet also tantalizingly, sub-daily shifts between these element/Ca ratios can be observed. In comparison to a lower-resolution, seasonally-resolved δ 18 O–Mg/Ca record (Warter et al., 2015), the ~ 10–20 μm element/Ca cycles are determined to be daily in origin, and a further ~ 14–15 day cyclicity is superimposed on the daily cycles. The latter is interpreted to reflect (Miocene) tidal periodicity. Changes in pixel intensity during thin section observation associated with micro- and macroscopically visible low and high density bands have been quantified via image processing analysis. This reveals close correspondence to the measured trace elemental cyclicity, indicating a coupling between the geochemical composition of the shell and the incremental growth pattern. A comparison between the elemental and image processing results reveals that ultra-high-resolution LA-ICPMS analysis surpasses the latter in detecting environmental rhythms, including daily and tidal cycles. Highly-resolved LA-ICPMS analysis is a viable alternative to nanoSIMS and opens up routine investigation of long-term (deep-time) paleoenvironmental records at daily resolution. [ABSTRACT FROM AUTHOR]

Apatite is a key mineral whose Sr-isotope record has a wide range of applications including palaeofluid flow studies from inorganic apatite, and past faunal/human mobility or palaeoecology using bioapatite. The incremental growth of mammalian enamel bioapatite potentially allows extraction of Sr isotopic compositions at sub-annual time-resolution using laser-ablation plasma mass spectrometry (LA-MC-ICPMS). However, existing apatite LA-MC-ICPMS Sr-isotope data have yielded mixed results. Here we assess the achievable accuracy/precision of (bio)apatite LA-MC-ICPMS Sr-isotope analysis and evaluate sources of inaccuracy. Using robust plasma conditions (ThO+/Th+ ＜ 0.2%), we obtain long-term (4 year) accurate and precise Sr-isotope data for modern shark teeth for both radiogenic 87Sr/86Sr (0.709171 ± 0.000053, 2 SD), and naturally invariant 84Sr/86Sr (0.056500 ± 0.000040, 2 SD). Based on our accurate 84Sr/86Sr-results also for low-Sr enamel, we deduce that interferences are successfully corrected (Kr) or negligible (Ca-argide/dimer), leaving 87Rb and 40Ca31P16O isobaric interferences as key potential sources for 87Sr/86Sr inaccuracy. Our (pseudo)high-resolution mass scans using a virtually Rb–Sr-free, concentrated Ca–P-solution simulating apatite LA analysis show no evidence for 40Ca31P16O at the required intensities to explain previously observed 87Sr/86Sr offsets. Rather, using the same Ca–P solution with varying Rb + Sr isotope standard additions, we accurately constrain the mass bias-corrected 85Rb/87Rb-ratio, and using apatite glasses assess the extent of Rb/Sr elemental fractionation during laser-ablation. Finally, we present concordant LA-MC-ICPMS and microsampled-TIMS 87Sr/86Sr results for low-Sr tooth enamel with highly variable inter & intra-87Sr/86Sr ratios and comparatively high Rb/Sr-ratios. This archaeological example also illustrates well the problem of defining equivalent sample volumes that allow unequivocal comparison between LA and TIMS data. [ABSTRACT FROM AUTHOR]

Trace element concentrations in biogenic and inorganic carbonates are a valuable source of palaeoenvironmental information. Because laser-ablation spot or 1D track analyses do not fully capture the complex (bio)mineralisation processes, 2D maps are required to arrive at a better understanding of the controls on minor/trace element incorporation. Foraminifera (marine protists) have a complex internal geometry and yield discontinuous sections characterised by calcite–resin–calcite transitions over distances as small as 10 μm. Order of magnitude differences in the total ion beam intensity over such transitions enables effective data exclusion. Inline signal smoothing devices, despite slightly increasing washout time and thus reducing spatial resolution, prevent excessive artificial noise in analyses, of particular concern when utilising small laser spot sizes (＜30 μm) in order to maximise spatial resolution. We find surface Al/Ca and Zn/Ca ratios elevated by two and 5–10 times respectively, highlighting the need for pre-acquisition ablation cleaning. Through these analytical considerations we show how the quality of images acquired from discontinuous samples can be maximised, enabling – in this case – seasonality reconstruction in the fossil record from large benthic foraminifera. [ABSTRACT FROM AUTHOR]

Abstract: A new add-on package (LAICPMS) for the R language for statistical computing is presented, which greatly facilitates data reduction and visualisation (single tracks and 2D element maps) of laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) data. The package determines many input parameters automatically and is easy to use. We present major and trace element distribution maps of natural calcite samples, processed using LAICPMS. Data processing from raw data to presented graphics takes only a few minutes. The empirical cumulative density function (ECDF) is used for optimised colour coding of the maps rather than linear or logarithmic scale, making a maximum of element-specific detail visible. For preprocessing, several different smoothing algorithms were evaluated and can be chosen by the user; for the presented data, a simple running median/running average was chosen. Typical data analysis is performed via short, easy-to-understand script files, and results can be used for further analyses within R. Owing to other R add-on packages utilised, the results can be output either numerically or as high-quality graphics in a wide range of file formats. Inheriting from its host environment R, the package is open-source software and freely available for all major computer platforms. [Copyright &y& Elsevier]

Time must be integrated with other geologic parameters such as pressure–temperature (P-T), composition or structural–textural information in order to quantify the dynamics of geologic processes like mountain building, faulting, metamorphism or magmatism. In the past, this connection was weak due to large sample sizes required in geochronology; however, recent developments open up exciting new possibilities. Texturally controlled in situ dating of minerals utilizing UV–laser ablation 40Ar/39Ar or Rb–Sr microsampling facilitates the crucial link between ages and textures at high spatial resolution. In situ U–Pb ages of accessory minerals can now be linked to the corresponding P-T evolution via their characteristic trace elemental signatures, indicative of mineral reactions in rocks. Garnet dating by Sm–Nd, and more recently Lu–Hf, can greatly benefit from both laser ablation inductively coupled plasma mass spectrometry (ICPMS) screening and improved leaching strategies, improving the link between time and P-T. Such integrated approaches can yield the duration and rates of deformation in shear zones, the rates of burial and exhumation of subducted rocks or the duration of entire metamorphic loops, to name a few. Potential for further development is identified in diverse areas. Dating of carbonate minerals related to brittle faulting using U–Pb could provide previously unavailable constraints on rates and duration of brittle deformation in the Earth’s upper crust. In situ Rb–Sr dating applicable to micas could become available using either laser ablation dynamic reaction cell-ICPMS or microbeam accelerator mass spectrometry. Other future developments and trends, and their limitations, are discussed briefly. [Copyright &y& Elsevier]

Three different geochronological techniques (stepwise-heating, laser-ablation [sup 40]Ar/[sup 39]Ar, Rb-Sr microsampling) have been evaluated for dating fault-generated pseudotachylytes sampled along the Periadriatic Fault System (PAF) of the Alps. Because pseudotachylytes are whole-rock systems composed of melt, clast and alteration phases, chemical control from both Ar isotopes (C1/K, Ca/K ratios) and EMPA analyses is crucial for their discrimination. When applied to stepwiseheating [sup 40]Ar/[sup 39]Ar analyses, this approach yields accurate melt-related ages, even for complex age spectra. The spatial resolution of laser-ablation [sup 40]Ar/[sup 39]Ar analyses is capable of contrasting melt, clast and alteration phases in situ, provided the clasts are not too fine grained, the latter of which results in integrated "mixed" ages without geological information. Elevated C1/K and Ca/K ratios were found to be an invaluable indicator for the presence of clast admixture or inherited [sup 40]Ar. Due to incomplete isotopic resetting during frictional melting, Rb-Sr microsampling dating did not furnish geologically meaningful ages. On the basis of isotopic disequilibria among pseudotachylyte matrix phases, and independent Rb-Sr microsampling dating of cogenetic (ultra)mylonites, the concordant [sup 40]Ar/[sup 39]Ar pseudotachylyte ages are interpreted as formation ages. The investigated pseudotachylytes altogether reveal a Cretaceous to Miocene history for the entire PAF, consistent with independent geological evidence. Individual faults, however, consistently reveal narrower intervals of enhanced activity lasting a few million years. Electronic supplementary material to this paper can be obtained by using the Springer LINK server at http://dx.doi.org/ 10. [ABSTRACT FROM AUTHOR]

Abstract: We report the first quantitative study of the capture of colloidal natural organic matter (NOM) and NOM-complexed trace metals (V, Co, Cu, Ni) in speleothems. This study combines published NOM–metal dripwater speciation measurements with high-resolution laser ablation ICPMS (LA-ICPMS) and sub-annual stable isotope ratio (δ18O and δ13C), fluorescence and total organic carbon (TOC) analyses of a fast-growing hyperalkaline stalagmite (pH ∼11) from Poole’s Cavern, Derbyshire UK, which formed between 1997 and 2008 AD. We suggest that the findings reported here elucidate trace element variations arising from colloidal transport and calcite precipitation rate changes observed in multiple, natural speleothems deposited at ca. pH 7–8. We find that NOM–metal(aq) complexes on the boundary between colloidal and dissolved (∼1nm diameter) show an annual cyclicity which is inversely correlated with the alkaline earth metals and is explained by calcite precipitation rate changes (as recorded by kinetically-fractionated stable isotopes). This relates to the strength of the NOM–metal complexation reaction, resulting in very strongly bound metals (Co in this system) essentially recording NOM co-precipitation (ternary complexation). More specifically, empirical partition coefficient (K d) values between surface-reactive metals (V, Co, Cu, Ni) [expressed as ratio of trace element to Ca ratios in calcite and in solution] arise from variations in the ‘free’ fraction of total metal in aqueous solution (f m). Hence, differences in the preservation of each metal in calcite can be explained quantitatively by their complexation behaviour with aqueous NOM. Differences between inorganic K d values and field measurements for metal partitioning into calcite occur where [free metal]≪[total metal] due to complexation reactions between metals and organic ligands (and potentially inorganic colloids). It follows that where f m ≈0, apparent inorganic K d app values are also ≈0, but the true partition coefficient (K d actual) is significantly higher. Importantly, the K d of NOM–metal complexes [organic carbon–metal ratio) approaches 1 for the most stable aqueous complexes, as is shown here for Co, but has values of 24–150 for V, Ni and Cu. This implies that ternary surface complexation (metal–ligand co-adsorption) can occur (as for NOM–Co), but is the exception rather than the rule. We also demonstrate the potential for trace metals to record information on NOM composition as expressed through changing NOM–metal complexation patterns in dripwaters. Therefore, a suite of trace metals in stalagmites show variations clearly attributable to changes in organic ligand concentration and composition, and which potentially reflect the state of overlying surface ecosystems. [Copyright &y& Elsevier]

The isotopic composition and abundance of trace elements in skeletal remains are often used for paleobiological and paleoecological reconstructions. Increasing attention is being paid to dental enamel as the most resilient tissue, but its pristine biogenic signature is obscured to varying degrees by secondary mineralization and diagenesis. We investigated these effects combining histomorphometry with the Sr isotope and trace element distribution in an Upper Paleolithic woolly mammoth molar using laser ablation (MC) ICPMS. We document a 12-year continuous record of seasonal changes in 87Sr/86Sr, Li, Pb and U whose distribution pattern follows incremental enamel growth features of the secretion stage of amelogenesis. Other elements are affected by enamel maturation proceeding along the Retzius lines with a decrease in uptake of Rb, Sr, Ba and/or Mg, an increase in uptake of Mn, and considerable enrichment of Zn. The Sr/Ba ratio is consistent with the seasonal pattern of the secretion stage, indicating a short time gap between the two mineralization phases, estimated to be no more than a few months. The maturation front determined by multi-element 2D mapping penetrates, locally, as far as the inner enamel but generally does not affect the region nearest the enamel-dentine junction, making this the optimal zone for obtaining accurate biogenic data. This allowed the preservation of seasonal fluctuations in Zn and Mg, absent in the regions affected by maturation. We interpret the seasonality as the result of changes in diet and metabolism during cold and warm periods that likely accompanied mammoth migration, as suggested by the parallel changes in the Sr isotopic composition. Diagenesis affected K, Mg and Mn, but only in a narrow zone at the contact with the cementum. The dentine is diagenetically altered but still preserves relics of seasonal compositional cycles, while the cementum is completely equilibrated with the depositional environment. [Display omitted] • Histomorphometry of a woolly mammoth dental plate enamel documents 12 years record. • In situ Sr isotopes and trace element abundance measurements show seasonal changes. • Secretion stage 87Sr/86Sr, Li, Pb and U distribution is unaffected by maturation. • 2D Sr/Ba mapping reflects maturation process. Seasonal variations are due to changes in diet, probably linked to migration. [ABSTRACT FROM AUTHOR]

Abstract: The timing and cause of late Pleistocene faunal extinctions in Australia are subjects of a debate that has become polarised by two vigorously defended views. One contends that the late Pleistocene extinction was a short event caused by humans colonising the Australian continent, whereas the other promotes a gradual demise of the fauna, over a period of at least 10–20ka, due to a combination of climatic changes and ecological pressures by humans. Cuddie Springs is central to this debate as it is the only site known in continental Australia where archaeological and megafauna remains co-occur. We have analysed more than 60 bones and teeth from the site by laser ablation ICP-MS to determine U, and Th concentrations and distributions, and those with sufficiently high U concentrations were analysed for U-series isotopes. Twenty-nine teeth were analysed by ESR. These new results, as well as previously published geochronological data, contradict the hypothesis that the clastic sediments of Stratigraphic Unit 6 (SU6) are in primary context with the faunal, archaeological and other materials found in SU6, and that all have ages consistent with the optically stimulated luminescence (OSL) estimates of 30–36ka. These young OSL results were used to argue for a relatively recent age of the extinct fauna. Our results imply that SU6 is either significantly older than the OSL results, or that a large fraction of the faunal material and the charcoal found in SU6 was derived from older, lateral deposits. Our U and Th laser ablation ICPMS results as well as the REE profiles reported by . Comparing rates of recystallisation and the potential for preservation of biomolecules from the distribution of trace elements in fossil bones. C.R. Palevol. General Paleontology (Taphonomy and Fossilization) 7, 145–158] contradict the interpretation of previously reported rare earth element compositions of bones, and the argument based thereon for the primary context of faunal material and clastic sediments in SU6 layers. [Copyright &y& Elsevier]

Several stalagmite records have yielded important but discontinuous insights into northern Iberian climate since the Last Glacial. Here we present the first continuous Iberian stalagmite-based reconstruction of climate since the Bølling-Allerød interstadial, from a single stalagmite sample (GAR-01 from La Garma Cave, Cantabria). The ∼13.5 ka GAR-01 record provides the opportunity for replication, continuation, and aggregation of previously published records from northern Spain. The GAR-01 record reveals shifts in oxygen isotope ratios that are inexplicable by appealing to a single control (i.e., exclusively temperature, rainfall amount, etc.). Herein we explore the potential role of rainfall and temperature seasonality shifts on the new δ18O record using a simple Monte Carlo approach to estimate the seasonal distribution of rainfall and the annual temperature range at 100-year timeslices across the record. This model is corroborated by intervals of monthly-resolved laser ablation trace element data, providing glimpses into past Iberian seasonality shifts. The most salient features of the modelled results include extremely dry Younger Dryas winters (∼12.9–11.6 ka BP) and several intervals during the mid-Holocene with almost no summer rainfall (e.g., at 4.2 and 9.0 ka BP). By 1.6 ka BP, a near-modern rainfall seasonality was established. According to the modelling results, seasonal rainfall and temperature distribution variability can account for 95% of the record. The model presented here provides a new tool for extracting critical missing seasonality information from stalagmite δ18O records. Intervals where the model does not converge may represent transient climate anomalies with unusual origins that warrant further investigation. • First continuous stalagmite reconstruction of North Iberian palaeoclimate spanning the Younger Dryas and Holocene. • The ∼13.5 ka GAR-01 record provides replication, continuation, and aggregation of existing regional stalagmite records. • N. Iberian stalagmite δ18O records largely covary but with a δ18O offset that reflects cave altitude and inland position. • Using a simple Monte Carlo approach, shifts in GAR-01 δ18O are explained by changing temperature and rainfall seasonality. • Monthly-resolved LA-ICPMS data provide glimpses into past Iberian seasonality shifts and corroborate the model. [ABSTRACT FROM AUTHOR]