18,319 research outputs found
The Maglemosian skeleton from Koelbjerg, Denmark revisited: identifying sex and provenance
The Koelbjerg individual, dated c. 8500 cal BC, represents the earliest human skeletal remains described from Scandinavia. Based on ancient DNA, strontium isotope and statistical anthropological analyses the individual’s sex, haplogroup and geographical provenance are here analysed and discussed. In contrast to previous claims, our genetic and anthropological analyses show that this individual was a male. Additionally, the strontium isotope ratio of one of his first molars indicates that he most likely grew up locally
The origins of the human remains from Perrins Ledge crematorium: strontium isotope ratio assessment of archaeological cremains
Strontium isotope (87Sr/86Sr) analyses have been used effectively to reconstruct the origin of osteological remains that have not been exposed to increasing temperatures (Bentley, 2006; Juarez, 2008; Knudson et al., 2005). However, previous research has shown that no thermally induced changes occur to original strontium isotope values (87Sr/86Sr) of bone and teeth specimens that have been subjected to temperatures between 212 and 1832 degrees Fahrenheit (Beard and Johnson, 2000; Grupe and Hummel, 1991; Harbeck et al., 2011), though the published literature regarding strontium isotope ratio stability and survivorship in thermally altered bone and teeth is limited. This is surprising given the potential implications for geolocation inquiries of cremains (or severely burnt remains) in both forensic and archaeological contexts. This research will focus on the latter context by using strontium isotope analyses, via thermal ionization mass spectrometry, to reconstruct the origins of human remains from a unique late Woodland period (A.D. 600-850) archaeological burial site known as the Perrins Ledge crematory, located in the lower Illinois River valley. Strontium isotope signatures derived from the Perrins Ledge cremains will be compared with values obtained from osteological faunal remains from three contemporary neighboring sites (Carlin, Apple Creek, and Newbridge). It is expected that the Perrins Ledge values will mirror those derived from the neighboring contemporary habitation sites suggesting local groups used the crematorium
Strontium Isotope as Tracers of Groundwater Contamination
Groundwater flowing under a municipal solid waste landfill has been studied to identify potential contamination phenomenon
and to test strontium isotopic composition as a natural tracer of contamination. The study was carried on in June 2014 in central Italy. Five selected boreholes were selected and analysed according to their location related to the site. Samples taken from boreholes placed upward to the site were considered as uncontaminated groundwater. One borehole located downward from the site and with major contaminant values has been considered as potentially contaminated end-member. Sr isotope results show that samples located upward from the site present lower Sr concentration and highest Sr isotopic values, which reflects weathered bedrock, while borehole located downward from the site show lowest Sr values and 87Sr/86Sr ratio, probably due to pollution by landfill leachate. The mixing calculation highlights the possible mixing phenomenon for the other samples located downward from the site
Evidence of hydrological control of Sr behavior in stream water (Strengbach catchment, Vosges mountains, France)
Strontium and particularly 87Sr/86Sr ratios in stream water have often been used to calculate weathering rates in catchments. Nevertheless, in the literature, discharge variation effects on the geochemical behavior of Sr are often omitted or considered as negligible. A regular survey of both Sr concentrations and Sr isotope ratios of the Strengbach stream water draining a granite (Vosges mountains, France) has been performed during one year. The results indicate that during low water flow periods, waters contain lower Sr concentrations and less radiogenic Sr isotope ratios (Sr=11.6 ppb and 87Sr/86Sr=0.7246 as an average, respectively) than during high water flow periods (Sr= 13 ppb and 87Sr/86Sr=0.7252 as an average, respectively). This is contrary to expected dilution processes by meteoric waters which have comparatively lower Sr isotopic ratios and lower Sr concentrations. Furthermore, 87Sr/86Sr ratios in stream water behave in 3 different ways depending on moisture and on hydrological conditions prevailing in the catchment. During low water flow periods (discharge < 9 l/s), a positive linear relationship exists between Sr isotope ratio and discharge, indicating the influence of radiogenic waters draining the saturated area during storm events. During high water flow conditions, rising discharges are characterized by significantly less radiogenic waters than the recession stages of discharge. This suggests a large contribution of radiogenic waters draining the deep layers of the hillslopes during the recession stages, particularly those from the more radiogenic north-facing slopes. These results allow one to confirm the negligible instantaneous incidence of rainwater on stream water chemistry during flood events, as well as the existence in the catchment of distinct contributive areas and reservoirs. The influence of these areas or reservoirs on the fluctuations of Sr concentrations and on Sr isotopic variations in stream water depends on both moisture and hydrological conditions. Hence, on a same bedrock type, 87Sr/86Sr ratios in surface waters can be related to flow rate. Consequently, discharge variations must be considered as a pre-requisite when using Sr isotopes for calculating weathering rates in catchments, particularly to define the range of variations of the end-members
Strontium isotope stratigraphy: LOWESS version 3: best fit to the marine Sr-isotope curve for 0-509 Ma and accompanying look-up table for deriving numerical age
An improved and updated version of the statistical LOWESS fit to the marine 87Sr/86Sr record and a revised look-up table (V3:10/99; available from [email protected]) based upon it enables straightforward conversion of 87Sr/86Sr to numerical age, and vice versa, for use in strontium isotope stratigraphy (SIS). The table includes 95% confidence intervals on predictions of numerical age from 87Sr/86Sr. This version includes the Triassic and Paleozoic record (0-509 Ma) omitted from previous versions because of the paucity of adequate data at the time of preparation. We highlight differences between the previous versions of the table and the current version and discuss some aspects of the 87Sr/86Sr record that may have geological significance. We give examples of how the table can be used and where it has proven useful
Sr-isotope analysis of speleothems by LA-MC-ICP-MS: High temporal resolution and fast data acquisition
Speleothems are well established climate archives. A wide array of geochemical proxies, including stable isotopes and trace elements are present within speleothems to reconstruct past climate variability. However, each proxy is influenced by multiple factors, often hampering robust interpretation. Sr isotope ratios (87Sr/86Sr) can provide useful information about water residence time and water mixing in the host rock, as they are not fractionated during calcite precipitation. Laser ablation multi-collector-inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) has rarely been used for determination of Sr isotope signatures in speleothems, as speleothems often do not possess appropriately high concentrations of Sr to facilitate this analysis. Yet the advantages of this approach include rapid data acquisition, higher spatial resolution, larger sample throughput and the absence of chemical treatment prior to analysis. We present LA-MC-ICP-MS Sr isotope data from two speleothems from Morocco (Grotte de Piste) and India (Mawmluh Cave), and we compare linescan and spot analysis ablation techniques along speleothem growth axes. The analytical uncertainty of our LA-MC-ICP-MS Sr data is comparable to studies conducted on other carbonate materials. The results of both ablation techniques are reproducible within analytical error, implying that this technique yields robust results when applied to speleothems. In addition, several comparative measurements of different carbonate reference materials (i.e. MACS-3, JCt-1, JCp-1), including tests with standard bracketing and comparison of the 87Sr/86Sr ratios with a nanosecond laser ablation system and a state-of-the-art femtosecond laser ablation system, highlight the robustness of the method
Early Neoproterozoic limestones from the Gwna Group, Anglesey
Limestone megaclasts up to hundreds of metres in size are present within the Gwna Group mélange, North Wales, UK. The mélange has been interpreted as part of a Peri-Gondwanan fore-arc accretionary complex although the age of deposition remains contentious, proposals ranging from Neoproterozoic to Early Ordovician. This paper uses strontium isotope chemostratigraphy to establish the age of the limestone blocks and thus provide a maximum age constraint on mélange formation. Results show that, although the carbonates are locally dolomitized, primary 87Sr/86Sr ratios can be identified and indicate deposition sometime between the late Tonian and earliest Cryogenian. This age is older than that suggested by stromatolites within the limestone and indicates that the limestone did not form as cap carbonate deposits
STRONTIUM ISOTOPE SYSTEMATICS AND GEOCHEMISTRY OF COAL UTILIZATION BY-PRODUCTS
Coal combustion for energy generation creates large quantities of solid coal utilization by-products (CUB), including fly ash, bottom ash, and flue gas desulfurization products. These materials are either used in environmental and industrial applications or stored adjacent to power plants. The development of new techniques to track and understand the behavior of CUB in the environment is essential to the safe utilization of coal. In this research, sequential leaching techniques are coupled with strontium (Sr) isotope analysis to investigate the influence of coal type and combustion process on the geochemical characteristics of CUB. Sequential leaches of water, acetic acid, and hydrochloric acid were carried out on a variety of CUB types. Systematic differences in 87Sr/86Sr ratios were observed (1) among different types of CUB, and (2) between leachates and their corresponding bulk CUB values. These differences can help elucidate the origins of the inorganic components of coal, as well as the transformations that occur during combustion. In addition, this study demonstrates for the first time that there are multiple sources of Sr in coal that remain isotopically distinct during combustion. The degree of isotopic homogenization induced during the formation of CUB appears to be controlled by the feed coal chemistry and the particular combustion technology used. The Sr isotope data, when combined with major and trace element results, suggest that a greater fraction of Sr is bound in detrital minerals in higher-rank coals, while authigenic minerals and organic complexes comprise the dominant form of Sr in lower-rank coals. Investigation of CUB produced from fluidized bed combustion (FBC) also demonstrates that the combustion process can strongly impact the behavior of the inorganic components of coal during utilization. The association of potentially toxic trace elements with certain soluble Sr-bearing phases in CUB make Sr isotopes a promising tool to trace the release of these species during interactions with water. Application of Sr isotopes to studies of coal and CUB could facilitate the development of better disposal techniques by serving as a robust tracer of CUB in the environment
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Mabel Davis Park Groundwater Investigation
In addition to other data, this report gathered 65 samples from Waller Creek to develop a table on present strontium isotope ratios.Pollutant transport from municipal solid waste landfills is most often caused by water movement through waste to natural groundwater and is measured directly in landfill leachate collection systems and downgradient wells, seeps, and springs. These data indicate the source of groundwater and may dictate alternate management for pollutant attenuation. Following remediation, the Mabel Davis landfill was monitored through comparison of leachate volume, rainfall, and well water levels. In addition, water chemistry analyses were conducted including isotopic ratios related to source waters. Data collected from these investigations indicates the St. Elmo Terrace Deposit is the source of natural groundwater on the site. It also appears that this natural shallow groundwater is the source for Mabel Davis seep and the observed fluctuation in leachate volume. As a result, leachate volumes will continue to fluctuate with seasonal rainfall amount with large amount of leachate being generated during wet periods and low leachate amounts during drought conditions. Solid Waste Services may want to consider alternatives for management of remediated landfill cover to redirect infiltrating rainfall and ultimately reduce production of leachate to within design parameters.Waller Creek Working Grou
Oxygen Isotope Analysis of Human Bone Phosphate Evidences Weaning Age in Archaeological Populations
Acknowledgements With special thanks to Jean-Jacques Hublin and the MPI-EVA; to Annabell Reiner (MPI-EVA) and Bernd Steinhilber (Universitat Tubingen) for technical support;and to the Deutscher Akademischer Austausch Dienst for financial support to KB during this project (ref: A0970923). This research was funded by the Max Planck Society. TT was financed by the DFG Emmy Noether Program and acknowledges funding by the grant TU 148/2-1 for the Emmy Noether Group Bone Geochemistry. Thanks also tothe University of Aberdeen for support during the preparation of this manuscript.Peer reviewedPostprin
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