Strontium isotope ratios (87Sr/86Sr) of incrementally grown tissues have been widely used to study movement ecology and migration of animals. However, the time scale of87Sr/86Sr incorporation from the environment into tissue and how it may influence data interpretation are still poorly understood. Using the relocation of a zoo elephant ( The87Sr/86Sr transition associated with the relocation is measured using laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) on a prepared tusk slab. We develop a turnover model (BITS), with a rapidly exchanging central pool and a slowly exchanging peripheral pool, in a Bayesian statistical framework. The measured dentine data are first used to calibrate model parameters. The parameters are then used to estimate possible87Sr/86Sr input time series from two datasets via model inversion: a fidelity test using Misha's dentine data and a case study using published dentine measurements from an Alaskan Woolly Mammoth ( The LA‐ICP‐MS data are consistent with a two‐compartment turnover process with equivalent half‐lives of 41 days for the central pool and 170 days for the peripheral pool. The model inversion shows good fidelity when estimating the intake87Sr/86Sr time series associated with Misha's relocation. In the case study, the model suggests an abrupt pattern of change in, and a much wider range of, intake87Sr/86Sr values than expressed in the woolly mammoth dentine data themselves. Our framework bridges the gap between environmental87Sr/86Sr variation and data measured in tusk dentine or other incrementally grown tissues. It could be coupled with movement models and additional isotope tracers to study seasonal residency or the spatial and temporal patterns of movement/migration. The generic turnover processes can be adapted to other isotope systems, additional incremental tissues, or other organisms, thus expanding our modelling toolkit to investigate niche partitioning, life history traits and behavioural patterns in conservation biology, archaeology and paleoecology.
Laser ablation tandem mass spectrometry is a burgeoning field for
- Award ID(s):
- 2233868
- NSF-PAR ID:
- 10441894
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Geostandards and Geoanalytical Research
- Volume:
- 47
- Issue:
- 4
- ISSN:
- 1639-4488
- Format(s):
- Medium: X Size: p. 795-809
- Size(s):
- p. 795-809
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract Loxodonta africana ) named Misha, we characterise and model the87Sr/86Sr turnover process using high‐resolution measurements of its tusk dentine. We seek to develop a framework that can improve quantitative interpretation of87Sr/86Sr data in tissues.Mammuthus primigenius ). -
Chauvel, Catherine (Ed.)In situ apatite U-Pb petrochronology and Sr-Nd isotope geochemistry requires well-characterized and matrix-matched references materials (RMs), yet only a few suitable apatite RMs are currently available. To ameliorate this issue, we determined the U-Pb, Sm-Nd, and Sr isotopic and elemental compositions of a suite of prospective apatite RMs using isotope dilution (ID) TIMS and laser ablation (LA) ICP-MS. The two RMs, from Morocco (MRC-1) and Brazil (BRZ-1), are cm-sized and available in significant quantities. The U-Pb ID-TIMS data yield an isochron age of 153.3 ± 0.2 Ma for MRC-1. This age is consistent with laser ablation split stream ICP-MS (LASS) analyses that produce an isochron age of 152.7 ± 0.6 Ma. The weighted mean of ID-TIMS analyses for 143Nd/144Nd analyses is 0.512677 ± 3, for 147Sm/144Nd is 0.10923 ± 9, and for 87Sr/86Sr is 0.707691 ± 2. The range and mean of TIMS Sm-Nd isotopic data are reproducible by LA-ICP-MS, but laser ablation Sr data are consistently offset towards more radiogenic values. For BRZ-1 apatite, ID-TIMS U-Pb analyses are dispersed, but a subset of the data yields a coherent age intercept of 2078 ± 13 Ma. The vast majority of LASS spot transects across the apatite produce an isochron that define a younger age of 2038 ± 14 Ma. We interpret this as incorporation of cryptic, younger altered domains within BRZ-1. Discordant U-Pb spot analyses are associated with chemically distinct cracks, likely a result of fluid infiltration. The weighted means of ID-TIMS analyses of BRZ-1 yield 143Nd/144Nd = 0.510989 ± 5, 147Sm/144Nd = 0.10152 ± 8, and 87Sr/86Sr = 0.709188 ± 3. The distribution of Nd isotopic compositions of this RM measured by LA-MC-ICP-MS analyses are comparable to TIMS analyses. By contrast, 87Sr/86Sr measurements by LA-ICP-MS are inaccurate and exhibit large uncertainties, but this RM can be useful for empirically correcting in situ 87Sr/86Sr measurements. The data indicate that MRC-1 apatite may serve well as a U-Pb, Sm-Nd, and Sr RM, whereas BRZ-1 apatite has the most potential as a Sm-Nd RM. These potential RMs provide new benchmarks for in situ apatite chemical analyses and inter-laboratory calibrations.more » « less
-
more » « less
Mounting evidence suggests that the Archaic Southeast shell mound builders had large‐scale trade networks and engaged in social aggregations. Here, incremental87Sr/86Sr values were measured by laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) in third molar enamel samples of 11 individuals interred in the Middle Archaic Harris Creek shell burial mound in St. John's River Valley (SJRV), Florida. Results reveal that SJRV residents engaged in short‐term, long‐distance mobility up to the Piedmont margin and excursions into coastal areas, consistent with direct trading and social gatherings. Two individuals are interpreted as migrants from central Tennessee, suggesting a link to the Ohio River Valley shell mound builders.
-
more » « less
Abstract We report40Ar‐39Ar step‐heating ages of Paleocene‐Eocene (P‐E) boundary impact spherules from Atlantic Margin coastal plain and open ocean sites. We test the hypothesis that the P‐E spherules are reworked from an earlier event (e.g., K‐Pg impact at ~66 Ma), which predicts a cooling age discordant from their depositional age of 55.93 ± 0.05 Ma at the P‐E boundary. Isochrons from the step‐heating analysis yield40Ar‐36Ar intercepts in excess of the modern in most cases, indicating that the spherules have excess radiogenic Ar (40Ar*), typical of impact glasses incompletely degassed before solidification. The weighted mean of the isochron‐corrected plateau age is 54.2 ± 2.5 Ma (1σ), and their isochron age is 55.4 ± 4.0 Ma, both indistinguishable from their P‐E depositional age, not supporting the K‐Pg reworking hypothesis. This is consistent with all other stratigraphic and geochemical evidence for an impact at the P‐E boundary and ejecta distribution by air fall.
-
more » « less
The Gejiu alkaline complex (GAC) within the western part of the Youjiang Basin provides a window to investigate the evolution in the junction of Cathaysia, Yangtze and Indochina blocks. Here, we investigate the GAC in terms of their petrology, zircon U–Pb geochronology, whole‐rock geochemistry, and Sr–Nd isotopic data to gain insights into the origin and evolution of the alkaline magma. The GAC is lithologically composed of alkali syenites and feldspathoid syenites, in which some were altered into sericite syenites. Zircon U–Pb dating of the alkali syenites yielded an age of 85.03 ± 0.47 Ma, which is slightly older than the feldspathoid syenites. The alkali syenites and feldspathoid syenites are silica‐saturated and silica‐undersaturated, respectively, and are characterized by high alkalinity with K2O + Na2O of 11.55–17.08 wt% and Al2O3of 18.57–22.49 wt%, low MgO of 0.11–1.39 wt%, weakly negative Eu anomalies, enrichments of LILEs such as Th and U, HFSEs like Zr and Hf but depletion of Ba, Sr, Nb, Ta, P, Ti, strongly fractionated LREEs to HREEs. Their uniform Sr–Nd isotope composition with initial87Sr/86Sr = 0.708802–0.710571 and
ε Nd(t ) = −7.1 to −6.6 indicates that they were products of a homologous magma. They crystallized atc . 810–956°C and have a relatively high magmatic oxygen fugacity. Our geochemical and isotopic data proved that the GAC magma was derived from the low‐degree partial melting (<10%) of a phlogopite‐bearing‐enriched mantle that was metasomatized by subducting sediments and originated possibly from the spinel and garnet transition zone at a depth of 60–80 km and a pressure of about 1.8–2.4 Gpa. The primary magma experienced protracted two‐stage crystal fractionation of clinopyroxene+amphibole and biotite+K‐feldspar, forming alkali syenites and feldspathoid syenites. Crustal contamination plays a negligible role in their formation. Considering previous tectonic studies, it was therefore proposed that the GAC formed in an extensional tectonic setting related to the Neo‐Tethyan tectonic regions during the Late Cretaceous.
