High resolution analysis of uranium and thorium concentration as well as U-series isotope distributions in a Neanderthal tooth from Payre (Ardèche, France) using laser ablation ICP-MS

We have mapped U (²³⁸U) and Th (²³²Th) elemental concentrations as well as U-series isotope distributions in a Neanderthal tooth from the Middle Palaeolithic site of Payre using laser ablation ICP-MS. The U-concentrations in an enamel section varied between 1 and 1500 ppb. The U-concentration maps show that U-migration through the external enamel surface is minute, the bulk of the uranium having migrated internally via the dentine into the enamel. The uranium migration and uptake is critically dependent on the mineralogical structure of the enamel. Increased U-concentrations are observed along lineaments, some of which are associated with cracks, and others may be related to intra-prismatic zones or structural weaknesses reaching from the dentine into the enamel. The uranium concentrations in the dentine vary between about 25,000 and 45,000 ppb. Our systematic mapping of U-concentration and U-series isotopes provides insight into the time domain of U-accumulation. Most of the uranium was accumulated in an early stage of burial, with some much later overprints. None of the uranium concentration and U-series profiles across the root of the tooth complied with a single stage diffusion-adsorption (D-A) model that is used for quality control in U-series dating of bones and teeth. Nevertheless, in the domains that yielded the oldest apparent U-series age estimates, U-leaching could be excluded. This means that the oldest apparent U-series ages of around 200 ka represent a minimum age for this Neanderthal specimen. This is in good agreement with independent age assessments (200-230 ka) for the archaeological layer, in which it was found.The Th elemental concentrations in the dental tissues were generally low (between about 1 and 20 ppb), and show little relationship with the nature of the tissue.     

洞穴地点骨化石铀系年龄可信度的讨论*

骨化石是铀不平衡系测年法广泛应用而又颇有争议的研究对象。文章通过对典型铀加入模式的计算,指出以α能谱的精度,二种铀系年龄差异的显著性表明近期内有较大量铀的迁移,但其在误差范围内的一致不能保证样品构成封闭体系。以往积累的数据表明,大多数洞穴地点骨化石给出了二法一致的铀系年龄,但钙板与下伏骨化石铀系年龄大多差异显著且与地层顺序矛盾,即使被次生碳酸盐岩包裹,多半骨化石的铀系年龄仍显著偏低于其包裹体。此外,相当一部分样品的U-Th同位素比难以用简单的铀后期加入或淋失来解释。基于对次生碳酸盐岩铀系年龄可信度的认识,骨化石总体上不构成封闭体系,所载铀系年代信息只具有限的分辨率。     

Diagenesis and the reconstruction of paleoenvironments: A method to restore original δO values of carbonate and phosphate from fossil tooth enamel

Intra-tooth δ¹⁸O variations within the carbonate (δ¹⁸Oc) and phosphate (δ¹⁸Op) components of tooth apatite were measured for Miocene and Pliocene hypsodont mammals from Afghanistan, Greece and Chad in order to evaluate the resistance of enamel to diagenetic alteration. Application of water-apatite interaction models suggest that the different kinetic behaviours of the phosphate-water and carbonate-water systems can be used to detect subtle oxygen isotope disequilibria in fossil enamel when intra-individual variations are considered. Selective alteration of the oxygen isotope composition from the carbonate component of Afghan and Greek enamels suggests inorganic isotopic exchange processes. Microbially-induced isotopic exchange for phosphate is demonstrated for the first time in enamel samples from Chad, in association with extensive recrystallization. In Chad, δ¹⁸Op values were derived from partial isotopic exchange with fossil groundwater during early diagenesis. Mass balance calculations using average carbonate content in enamel as a proxy for recrystallization, and the lowest δ¹⁸Op value of dentine as a proxy for the isotopic composition of the diagenetic fluid, indicate that diagenesis can alter δ¹⁸Op by as much as 3‰ in some enamel samples. This diagenetic alteration is also responsible for a decrease in intra-individual variations of up to 1‰ in affected specimens. The effects of diagenesis on δ¹⁸Op values of fossil enamel are not systematic, however, and can only be estimated if sequential δ¹⁸Op and δ¹⁸Oc analyses are performed on fossil enamel and dentine. Reconstruction of large temporal- or spatial-scale paleoclimates based on δ¹⁸Op analyses from mammalian teeth cannot be considered valid if enamel has been affected by bacterial activity or if the data cannot be corrected for diagenetic effects.     

第四纪骨化石样品的多方法对比测年

本文报道作者用¹⁴C、铀系和ESR等多种测年技术对比测定第四纪骨化石样品年龄结果,对比分析骨化石中各含碳组分¹⁴C年龄的异同。在此基础上讨论诸测年方法的可靠性和测年精度,分析哪种含碳组分最能代表骨质样品的真实年龄。对晚于40 000aB.P.的骨质样品,作者倾向于样品中氨基酸的¹⁴C测年,而对更老的样品,铀系法应优先被选用。本文还对北京周口店山顶洞遗址骨化石样品中不同含碳组分的¹⁴C测年结果做了讨论。     

Chemical and structural changes in Cervus elaphus tooth enamels during fossilization (Lazaret cave): a combined IR and XRD Rietveld analysis

Tooth enamel from modern and fossil (Lazaret cave) Cervus elaphus was characterized in order to study the chemical and structural changes during fossilization. Calcium, P, Na, Mg, F, Cl, CO₃, contents were measured by chemical analyses, and infrared (IR) spectroscopy was used to determine H₂0, OH⁻, P0₄³⁻ and C0₃²⁻. Carbonate increases during fossilization and substitutes for PO₄³⁻ at the B-site and for OH at the A-site. The C0₃²⁻-for-PO₄³⁻ substitution experiences the highest increase. Water and OH contents decrease during fossilization. These chemical changes may be traced by Rietveld structure refinement (XRD). Like human enamel, red deer enamel consists of apatite. A good positive correlation has been found between the a cell parameter and C0₃²⁻ contents. Refinement of atomic positions and site multiplicity allow us to describe site distortions in P0₄³⁻ polyhedra and along the 6₃ axis; these distortions are indirect probes of the substituent ions in the apatite structure.At Lazaret cave, the karstic environment is thought to control the chemical and structural changes of the fossil enamels. Fossilization conditions have been favorable for a good conservation of the Cervus elaphus tooth enamels whatever their stratigraphic position and location were. These fossil enamels have experienced only slight structural and chemical changes considering their geological age. This accounts for a rapid burial in continental sediments of Lazaret prehistoric cave. These Lazaret fossil enamels could be considered as stable material which may be used for dating by the ESR and U-Th methods.     

Timescales and mechanisms of REE and Hf uptake in fossil bones

Rare earth element (REE) patterns of fossil bones and teeth are widely used as proxies for provenance, taphonomy, and palaeoenvironment. In order to investigate if fossil bones behave as closed systems over geologic time, REE profiles were analysed by LA-ICPMS along cross sections of 54 bones from various well-characterised and well-dated settings. These include terrestrial and marine diagenetic environments, covering Early Triassic to Holocene ages. In general, all fossil bones exhibit the highest REE concentrations at the outer rim, gradually decreasing by up to four orders of magnitude toward the inner bone cortex. Intra-bone REE concentration gradients decrease significantly from Quaternary via Tertiary to Mesozoic specimens, suggesting long term REE uptake and open system behaviour of fossil bone. This view is further corroborated by ¹⁷⁶Lu-¹⁷⁶Hf dating of selected samples, all yielding significantly younger ages than the known chronostratigraphic ages. Hence, there is clear evidence for long term open system behaviour of fossil bones with respect to REE, which is in marked contrast to currently accepted models suggesting that REE uptake is only early diagenetic. Although unexpected, statistically significant four to seven point isochrons are observed for four fossil dinosaur bone samples and one Upper Triassic Mastodonsaurus tooth with MSWDs ranging from 0.083 to 4.5. Notably, mobility of Lu alone cannot account for the observed age patterns. Assuming constant Lu uptake rates over time, the radiometric ages should only be as low as half of the chronostratigraphic age. However, a six-point isochron defined by subsamples of a single Upper Triassic Mastodonsaurus tooth yields an age of 65.2 ± 1.1 Ma (MSWD = 0.68), much younger than half of the stratigraphic age (ca. 234 Ma). Hence, Hf must also undergo late diagenetic exchange. Likely mechanisms to account for the presence of statistically meaningful isochrons as well as for the late diagenetic exchange of both REE and Hf are diffusion, adsorption, and dissolution-reprecipitation processes.     

Sources of carbon isotope variation in kangaroo bone collagen and tooth enamel

The stable carbon isotopic composition (expressed as δ¹³C) of herbivore remains is commonly used to reconstruct past changes in the relative abundance of C₄ versus C₃ grass biomass (C₄ relative abundance). However, the strength of the relationship between herbivore δ¹³C and C₄ relative abundance in extant ecosystems has not been thoroughly examined. We determined sources of variation in δ¹³C of bone collagen and tooth enamel of kangaroos (Macropus spp.) collected throughout Australia by measuring δ¹³C of bone collagen (779 individuals) and tooth enamel (694 individuals). An index of seasonal water availability, i.e. the distribution of rainfall in the C₄ versus C₃ growing seasons, was used as a proxy for C₄ relative abundance, and this variable explained a large proportion of the variation in both collagen δ¹³C (68%) and enamel δ¹³C (68%). These figures increased to 78% and 77%, respectively, when differences between kangaroo species were accounted for. Vegetation characteristics, such as woodiness and the presence of an open forest canopy, had no effect on collagen or enamel δ¹³C. While there was no relationship between collagen δ¹³C and kangaroo age at death, tooth enamel produced later in life, following weaning, was enriched in ¹³C by 3.5‰ relative to enamel produced prior to weaning. From the observed relationships between seasonal water availability and collagen and enamel δ¹³C, enrichment factors (ε^∗) for collagen-diet and enamel-diet (post-weaning) were estimated to be 5.2‰ ± 0.5 (95% CI) and 11.7‰ ± 0.6 (95% CI), respectively. The findings of this study confirm that at a continental scale, collagen and enamel δ¹³C of a group of large herbivores closely reflect C₄ relative abundance. This validates a fundamental assumption underpinning the use of isotopic analysis of herbivore remains to reconstruct changes in C₄ relative abundance.     

Oxygen isotopic composition of mammalian skeletal phosphate from the Natufian Period,Hayonim Cave,Israel: Diagenesis and paleoclimate

Recent and fossil (prehistoric, Natufian) gazelle bones, dentin and enamel were analyzed for their oxygen isotopic composition (δ¹⁸O) of the phosphate and carbonate, as well as their crystallinity. Fossil bones and dentin have better crystallinity than recent specimens, indicating diagenetic change. Fossil enamel, on the other hand, is identical in crystallinity to recent enamel, indicating the lack of diagenetic alteration. Comparison of δ¹⁸O of carbonate and phosphate of the skeletal elements suggests that the coexisting phosphate and carbonate of both the recent and fossil specimens are close to isotopic equilibrium. This might suggest that both phases were affected by the same degree of diagenetic alteration, and that comparison of their δ¹⁸O is not useful for the selection of pristine material for paleoclimatic reconstruction purposes. Oxygen isotope analysis of gazelle enamel from the Natufian period from Hayonim Cave, Israel, show depletion in δ¹⁸O in comparison with recent enamel. This depletion is interpreted to represent a colder and/or wetter climate in the Natufian of northern Israel. © 1999 John Wiley & Sons, Inc.     

Seasonal variation in kangaroo tooth enamel oxygen and carbon isotopes in southern Australia

Serial sampling of tooth enamel growth increments for carbon and oxygen isotopic analyses of Macropus (kangaroo) teeth was performed to assess the potential for reconstructing paleoseasonality. The carbon isotope composition of tooth enamel apatite carbonate reflects the proportional intake of C₃ and C₄ vegetation. The oxygen isotopic composition of enamel reflects that of ingested and metabolic water. Tooth enamel forms sequentially from the tip of the crown to the base, so dietary and environmental changes during the tooth's formation can be detected. δ¹³C and δ¹⁸O values were determined for a series of enamel samples drilled from the 3rd and 4th molars of kangaroos that were collected along a 900 km north–south transect in southern Australia. The serial sampling method did not yield pronounced seasonal isotopic variation patterns in Macropus enamel. The full extent of dietary isotopic variation may be obscured by attenuation of the isotopic signal during enamel mineralisation. Brachydont (low-crowned) Macropus teeth may be less sensitive to seasonal variation in isotopic composition due to time-averaging during mineralisation. However, geographic variations observed suggest that there may be potential for tracking latitudinal shifts in vegetation zones and seasonal environmental patterns in response to climate change.     

A 16-Ma record of paleodiet using carbon and oxygen isotopes in fossil teeth from Pakistan

The Siwalik Sequence of northern Pakistan contains a 16-Ma record of paleosol carbonate and fossil teeth from which a record of paleovegetation can potentially be reconstructed and compared. The carbon isotopic composition of paleosol carbonate and organic matter from Siwalik strata reflects a major paleoecological change on the floodplains of major rivers beginning7.3 Ma ago. By 6 Ma C₃-dominated plant communities, probably composed of mostly trees and shrubs, were displaced by nearly continuous C₄ grassland. We find that the carbon isotopic ratios in herbivore tooth enamel reflect this dramatic ecologic shift. Carbonate in enamel older than 7 Ma averages −11‰ in δ¹³C_PDB, consistent with a largely C₃ diet. Enamel from the Plio-PIeistocene averages +1.9‰ in δ¹³C, similar to the value displayed by modern C₄ grazers. Analysis of post-burial carbonate cements, and the concordance with isotopic evidence from paleosols argues strongly against major isotopic alteration of the enamel, while coexisting bone may have been altered early in burial. This study confirms that enamel apatite is useful for paleodietary reconstruction much further back in the geologic record than was previously thought.     

ESR dating and the human evolution: contribution to the chronology of the earliest humans in Europe

In the last 20 years, the electron spin resonance (ESR) dating method has allowed the establishment of a chronological time frame over most of the history of human evolution. Despite many difficulties found for ESR dating of bones and carbonates, tooth enamel dated by ESR has been proven as a reliable method in its application to fossil teeth and quartz. Both of the latter materials have allowed dating of Early and Middle Pleistocene sites which are not datable using other methods such as the Argon–Argon method. In particular, recent discoveries of human remains in western Europe have been proposed to be sites of the earliest arrival of humans there, and have been dated to the Early Pleistocene by ESR using quartz and tooth enamel.Combined ESR and U-series dating of fossil herbivore teeth are the only means of dating layers from which such ancient remains have been recovered in western Europe. Good examples are the sites of Atapuerca Gran Dolina, Spain and Visogliano, Italy which have been dated using tooth enamel.When no bones and teeth can be found in prehistoric sites, ESR dating on quartz extracted from sediments has been used to date sites whose ages range over the entire Quaternary period. We present here two examples that occur in fluvial terraces of the river Creuse, France and at Monte Poggiolo site, Italy, where several artefacts of an archaic pebble industry have been recovered.     

U—Series Dating of Fossil Bones：Results from Chinese Sites and Discussions on Its Reliability

Calculations,according to some open-system models,point out that while a statistically significant discrepancy between the results of two U-series methods,^230Th/^234U and ^227Th/^220Th(or ^231Pa/^235U),attests a relatively recent and important uranium migration,concordant dates cannot guarantee closes-system behavior of sample.The results of 20 fossil bones from 10 Chinese sites,19 of which are determined by two U-series methods,are given,Judging from independent age controls,8 out of the 11 concordant age sets are unacceptable,The results in this paper suggest that uranium may cycle into or out of fossil bones,such geochemical events may take place at any time and no known preserving condition may securely protect them from being affected.So for the sitew we have studied,the U-series dating of fossil bones is of limited reliability.     

The timing of sea-level high-stands during Marine Isotope Stages 7.5 and 9: Constraints from the uranium-series dating of fossil corals from Henderson Island

Direct dating of fossil coral reefs using the U-series chronometer provides an important independent test of the Milankovitch orbital forcing theory of climate change. However, well-dated fossil corals pre-dating the last interglacial period (>130 thousand years ago; ka) are scarce due to, (1) a lack of sampling localities, (2) insufficient analytical precision in U-series dating methods, and (3) diagenesis which acts to violate the assumption of closed-system U-series isotopic decay in fossil corals. Here we present 50 new high-precision U-series age determinations for fossil corals from Henderson Island, an emergent coral atoll in the central South Pacific. U-series age determinations associated with the Marine Isotope Stage (MIS) 9 interglacial and MIS 7.5 interstadial periods are reported. The fossil corals show relatively little open-system U-series behaviour in comparison to other localities with fossil coral reefs formed prior to the last glacial cycle, however, open-system U-series behaviour is still evident in most of the dated corals. In particular, percent-level shifts in the [²³⁰Th/²³⁸U]_act composition are observed, leading to conventional U-series ages that are significantly younger or older than the true sample age. This open-system U-series behaviour is not accounted for by any of the open-system U-series models, indicating that new models should be derived. The new U-series ages reported here support and extend earlier findings reported in Stirling et al. (2001), providing evidence of prolific coral reef development on Henderson Island at ∼320 ka, most likely correlated with MIS 9.3, and subsequent reef development at ∼307 ka during MIS 9.1, while relative sea-level was potentially ∼20 m lower than during MIS 9.3. The U-series ages for additional well-preserved fossil corals are suggestive of minor reef development on Henderson Island during MIS 7.5 (245-230 ka) at 240.3 ± 0.8 and 234.7 ± 1.3 ka. All U-series observations are consistent with the Milankovitch theory of climate change, in terms of the timing of onset and termination of the dated interglacial and interstadial periods. The best preserved samples also suggest that the oceanic ²³⁴U/²³⁸U during MIS 9 and MIS 7.5 was within five permil of the modern open ocean composition.     

Oxygen isotope analysis of bone and tooth enamel phosphate from paleogene sediments: Experimental techniques and initial results

Oxygen isotope composition (δ¹⁸O) of fossil bone and tooth enamel phosphate (bioapatite) is an important tool for estimating the isotopic composition of past environmental water. Lack of analytical facility was a hindrance for studying such bioapatites in spite of large number of fossil materials reported from various geological ages in India. We have established in our laboratory, based on available methods, the chemical procedure for extraction of very small amount (<1000 μg) PO₄ ⁻³ from bioapatite and on-line mass spectrometric measurement of its δ¹⁸O composition by high temperature (∼1450°C) pyrolysis. The achieved precision is ∼± 0.3 ‰ similar to obtained elsewhere, with interlaboratory calibration showing excellent agreement of standard phosphates. Inferred δ¹⁸O values of environmental water, based on the analysis of teeth and bones of sharks, fish and terrestrial mammals from the Paleogene successions of the northwest sub-Himalayan and the Peninsular India show strong correspondence with animal habitats. The freshwater δ¹⁸O values are much depleted having range similar to modern monsoon precipitation. However, owing to our small dataset it is not possible at this stage to infer about the existence of monsoon over the Indian sub-continent during the Eocene-Oligocene time.     

Calcium isotopes in fossil bones and teeth — Diagenetic versus biogenic origin

We present the first systematic study of Ca isotopes (δ^44/40Ca) in Late Triassic to Late Cretaceous dinosaur bones and teeth (enamel and dentin) from sympatric herbivorous and carnivorous dinosaurs. The samples derive from five different localities, and data from embedding sediments are also presented. Additional δ^44/40Ca in skeletal tissues from modern reptiles and birds (avian dinosaurs) were measured for comparison in order to examine whether the original Ca isotopic composition in dinosaur skeletal apatite was preserved or might have changed during the diagenesis and fossilization process.δ^44/40Ca of fossil skeletal tissues range from −1.62‰ (Tyrannosaurus rex enamel) to +1.08‰ (Brachiosaurus brancai bone), while values in modern archosaur bones and teeth range from −1.63‰ (caiman enamel) to −0.37‰ (ostrich bone). The average δ^44/40Ca of the three types of fossil skeletal tissue analyzed - bone, dentin and enamel - show some systematic differences: while δ^44/40Ca in bone exhibits the highest values, while δ^44/40Ca in enamel has the lowest values, and dentin δ^44/40Ca falls in between. Values of δ^44/40Ca in the remains of herbivorous dinosaurs (0.1-1.1‰) are generally higher than those of bones of modern mammalian herbivores (−2.6‰ to −0.8‰) and from modern herbivorous archosaurs, which exhibit intermediate δ^44/40Ca (−0.8‰ to −0.4‰). These systematic isotopic shifts may reflect physiological differences between dinosaurs, mammals and reptiles representing different taxonomic groups of vertebrates.Systematic offsets in skeletal apatite δ^44/40Ca between herbivorous and carnivorous dinosaurs are not obvious, indicating a lack of a clear-cut Trophic Level Effect (TLE) shift between herbivores and carnivores in dinosaurs. This observation can be explained if the carnivorous dinosaurs in this study fed mainly on soft tissues from their prey and did not ingest hard (calcified) tissue to much extent. The most striking indication that the primary δ^44/40Ca is actually preserved in most of the fossil teeth is a difference in δ^44/40Ca of about 0.35 ± 0.10‰ (1SD) between dentin and enamel, based upon 11 of 16 analyzed dentin-enamel pairs. This difference is close to that found in modern reptiles (0.28 ± 0.05‰), and strongly suggests that this tell-tale signature is a primary feature of the fossilized dinosaur material as well. Furthermore, simple mass balance calculations show that changes of the original δ^44/40Ca in bones and teeth by diagenetically-formed calcium-bearing minerals are either small or would require implausible high original δ^44/40Ca values in the skeletal apatite.     

文石-方解石石笋U/Th体系的封闭性判断及意义

湖南省龙山县莲花洞两根大型石笋LLl(文石-方解石型)和LL5(文石型)ICP-MS230Th结果表明,82个年龄数据并不完全符合石笋生长层序律.根据U/Th同位素比值、沉积和矿物学特征,分析了同位素体系开放度对建立石笋正确年代学模式的影响.莲花洞LLl石笋全新世以来234U/238U对230Th/238U的比值具有谐和性特征并且230Th年龄层序正常,说明文石矿物基本接近U/Th同位素封闭系统,实测年龄基本可靠.10～40 ka期间234U/238U与230Th/238U离散度较大和矿物具有溶蚀、风化现象,表明体系发生U加入/流失作用.LL5石笋60～80 ka期间封闭性较好,实测年龄可信.上述结果表明,同一洞穴中文石石笋U/Th同位素体系开放度与时间的关系并不是线性关系,沉积时水文和物理化学性质以及随后的保存状况是决定洞穴文石石笋同位素封闭性的关键因素.     

Electron spin resonance (ESR) and thermal ionization mass spectrometric (TIMS) 230Th/234U dating of teeth in Middle Paleolithic layers at Amud Cave,Israel

Electron spin resonance (ESR) dating and thermal ionization mass spectrometric ²³⁰Th/²³⁴U dating was conducted on six teeth from the prehistoric site of Amud Cave. By combining the ESR and ²³⁰Th/²³⁴U analyses, we obtained burial ages for teeth in various layers of the site. Layer B₁/6–7, from which the Amud I Neanderthal skeleton was recovered, is dated to 53 ± 8 ka. Layer B₂/8, which yielded other important human remains including the Amud 7 skeleton, gives a mean burial age of 61 ± 9 ka. One tooth from the lowest layer (B₄) yielded a date of 70 ± 11 ka, but another tooth from this layer gave an 113 ± 18 ka. Despite this discrepancy, these ages agree with previously published TL ages on heated flints for the corresponding layers. This agreement between ESR on tooth enamel and TL on burned flint is also seen at all other sites studied with both methods in Israel. © 2001 John Wiley & Sons, Inc.     

230Th/234U dating of Holocene tufas: possibilities and problems

High-resolution chronologies in continental carbonate deposits such as tufas are required for detailed palaeoclimatic and environmental studies. This work set out to establish if high-resolution U-series dating of detritus-rich Holocene tufas is routinely possible. The study centres on a paludal Holocene tufa from southern England that already has an existing Holocene chronology, based on ¹⁴C and supported by biostratigraphy, against which to compare U-series dates. The results show that significant detrital contamination combined with low initial U concentrations, and short time for ingrowth of radiogenic ²³⁰Th make high-resolution U-series dating of Holocene tufa very difficult. Moreover, a single (²³⁰Th/²³²Th)_initial value to correct for the presence of detrital ²³⁰Th is not appropriate at the study site, a finding that may apply to most Holocene tufas. Total sample dissolution of coeval samples demonstrates considerable variability in the isotopic composition of the detritus. The total sample dissolution data are too scattered to constrain chronologies at the required resolution and may indicate the incorporation of a ²³⁰Th-rich component in the detritus.     

U-Th dating of Lake Lisan (late Pleistocene dead sea) aragonite and implications for glacial east Mediterranean climate change

U-series dating can be an effective means to obtain accurate and precise ages on Quaternary carbonates. However, most samples require a correction for U and Th in admixed detritus. This complication is often addressed through generation of U-Th isochrons, requiring analyses of several coeval samples. In addition, presence of water-derived (hydrogenous) Th in the carbonate can cause inaccuracies in isochron ages.This study reports a high-resolution U-series chronology of sediments deposited by Lake Lisan, the last glacial precursor of the Dead Sea. The strategy employed combines multiple measurements from a few stratigraphic heights and fewer analyses from many heights in a single described and measured section. The resulting chronology is based on ages at 22 heights in a ∼40-m-thick section covering the interval of ∼70-14 calendar ka BP. The effects of admixed detritus are evaluated using trace elements. Nearly pure aragonite samples, indicated by very low abundances of insoluble elements such as Nb and Zr, were found to contain hydrogenous Th, which causes the uncorrected U-²³⁰Th age of a modern sample to be ∼2.5 ka. Nevertheless, accurate ages have been obtained by correcting for the detrital and aqueous interferences. The resulting ages are in stratigraphic order, and their accuracy is evidenced by consistency of Lisan Formation U-series and ¹⁴C ages with the coral-based calendar-radiocarbon age calibration.The U-Th ages provide a context to unravel the limnological history of Lake Lisan. Boundaries between the Lower, Middle, and Upper stratigraphic units correspond to the MIS 4/3 and 3/2 transitions, respectively. During MIS 2 and 4 the lake generally showed a stable two-layer configuration and a positive fresh-water balance, reflected by deposition of laminated aragonite-detritus. Dry intervals during MIS 2 and 4 are indicated by thick gypsum layers and an inferred depositional hiatus, which are temporally associated with Heinrich events H1 at ∼17 ka and H6 at ∼65 ka, respectively. During MIS 3 the lake level was unstable with intermittent dry periods indicated by abundant clastic layers and a significant hiatus between ∼43-49 ka. Clastic layers are associated with Dansgaard-Oeschger events during MIS 3, and indicate lake level declines during abrupt Northern Hemisphere warmings. Overall, the climate of the Eastern Mediterranean region shows a strong linkage to the Northern Hemisphere climate, with increasing lake size and stability during cold periods, and fluctuations and dessication during warmings and Heinrich events.