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1.
PLoS One ; 19(5): e0302854, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38722950

RESUMO

For management efforts to succeed in Caribbean fisheries, local fishers must support and be willing to comply with fishing regulations. This is more likely when fishers are included in a stock assessment process that utilizes robust scientific evidence, collected in collaboration with fishers, to evaluate the health of fish stocks. Caribbean parrotfishes are important contributors to coral reef ecosystem health while also contributing to local fisheries. Scientifically robust stock assessments require regional species-specific information on age-based key life history parameters, derived from fish age estimates. Evaluation of the accuracy of age estimation methods for fish species is a critical initial step in managing species for long-term sustainable harvest. The current study resulted from a collaborative research program between fish biologists and local fishers investigating age, growth, and reproductive biology of the seven parrotfish species landed in U.S. Caribbean fisheries; specifically, we validated age estimation for stoplight parrotfish Sparisoma viride and queen parrotfish Scarus vetula. This is the first study to directly validate age estimation for any parrotfish species through analysis of Δ14C from eye lens cores. Our age estimation validation results show that enumeration of opaque zones from thin sections of sagittal otoliths for a Sparisoma and a Scarus species provides accurate age estimates. The oldest stoplight parrotfish and queen parrotfish in the Δ14C age estimation validation series were 14 y and 16 y; while the oldest stoplight parrotfish and queen parrotfish we aged to-date using the Δ14C validated age estimation method were 20 y and 21 y, respectively. Fish longevity (maximum age attained/life span) is a key life history parameter used for estimation of natural mortality, survivorship, and lifetime reproductive output. Past reviews on parrotfishes from the Pacific and Atlantic concluded that most Caribbean/western Atlantic parrotfish species are relatively short-lived with estimated maximum ages ranging from 3-9 y. However, information from our collaborative research in the U.S. Caribbean combined with recently published age estimates for Brazilian parrotfish species indicate that many western Atlantic parrotfishes are relatively long-lived with several species attaining maximum ages in excess of 20 y.


Assuntos
Pesqueiros , Longevidade , Animais , Perciformes/crescimento & desenvolvimento , Perciformes/fisiologia , Conservação dos Recursos Naturais/métodos , Região do Caribe , Datação Radiométrica/métodos , Oceano Atlântico
2.
PLoS One ; 19(5): e0300749, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38723036

RESUMO

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.


Assuntos
Osso e Ossos , Sepultamento , Isótopos de Carbono , Isótopos de Nitrogênio , Humanos , Isótopos de Carbono/análise , Feminino , Isótopos de Nitrogênio/análise , Masculino , Sepultamento/história , Osso e Ossos/química , Adulto , Fiji , Arqueologia , Dieta/história , Colágeno , História Antiga , Dente/química , Criança , Datação Radiométrica/métodos
3.
Sci Rep ; 14(1): 10885, 2024 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-38740801

RESUMO

The squash family (Cucurbitaceae) contains some of the most important crops cultivated worldwide and has played an important ecological, economic, and cultural role for millennia. In the American tropics, squashes were among the first cultivated crop species, but little is known about how their domestication unfolded. Here, we employ direct radiocarbon dating and morphological analyses of desiccated cucurbit seeds, rinds, and stems from El Gigante Rockshelter in Honduras to reconstruct human practices of selection and cultivation of Lagenaria siceraria, Cucurbita pepo, and Cucurbita moschata. Direct radiocarbon dating indicates that humans started using Lagenaria and wild Cucurbita starting ~ 10,950 calendar years before present (cal B.P.), primarily as watertight vessels and possibly as cooking and drinking containers. A rind directly dated to 11,150-10,765 cal B.P. represents the oldest known bottle gourd in the Americas. Domesticated C. moschata subsequently appeared ~ 4035 cal B.P., followed by domesticated C. pepo ~ 2190 cal B.P. associated with increasing evidence for their use as food crops. Multivariate statistical analysis of seed size and shape show that the archaeological C. pepo assemblage exhibits significant variability, representing at least three varieties: one similar to present-day zucchini, another like present-day vegetable marrow, and a native cultivar without modern analogs. Our archaeobotanical data supports the hypothesis that Indigenous cucurbit use started in the Early Holocene, and that agricultural complexity during the Late Holocene involved selective breeding that encouraged crop diversification.


Assuntos
Arqueologia , Produtos Agrícolas , Cucurbita , Humanos , Cucurbita/anatomia & histologia , Datação Radiométrica/métodos , História Antiga , Cucurbitaceae/anatomia & histologia , Domesticação , Sementes/química , Honduras
4.
Proc Natl Acad Sci U S A ; 121(18): e2320506121, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38648488

RESUMO

In deserts, water has been singled out as the most important factor for choosing where to settle, but trees were likely an important part of the landscape for hunter-gatherers beyond merely constituting an economic resource. Yet, this critical aspect has not been considered archaeologically. Here, we present the results of mapping and radiocarbon dating of a truly unique archaeological record. Over 150 preserved stumps around five Late Pleistocene/Early Holocene archaeological campsites (12,800 to 11,200 cal BP) show that trees were key features in the creation of everyday habitats for the first inhabitants of the Atacama Desert. At two of these sites, QM12 and QM35, the spatial and chronological correlation between trees and hearths reveals that people located their homes under the tree canopy. At residential site QM35, artifact distribution coincides with a grove dated to ~11,600 to 11,200 cal BP. A third residential area (QM32) occurred along the grove margins ~12,000 to 11,200 cal BP. Based on the distinct cultural material of these two camps, we propose that two different groups intermittently shared this rich wetland-grove environment. The tree taxa suggest a preference for the native Schinus molle, a tree scarcely present on the landscape today, over the endemic, nitrogen-fixing Strombocarpa tamarugo, both for toolmaking and firewood and even though the S. tamarugo was locally more abundant. Together with the spatial and chronological coincidence of campsites, hearths, and trees, we propose that people spared the most abundant and resilient species to create their homes, in turn promoting fertility oases amid the Atacama's hyperaridity.


Assuntos
Arqueologia , Clima Desértico , Árvores , Humanos , História Antiga , Ecossistema , Datação Radiométrica , Chile
5.
Nat Commun ; 15(1): 3611, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38684677

RESUMO

The emergence of Homo sapiens in Eastern Asia is a topic of significant research interest. However, well-preserved human fossils in secure, dateable contexts in this region are extremely rare, and often the subject of intense debate owing to stratigraphic and geochronological problems. Tongtianyan cave, in Liujiang District of Liuzhou City, southern China is one of the most important fossils finds of H. sapiens, though its age has been debated, with chronometric dates ranging from the late Middle Pleistocene to the early Late Pleistocene. Here we provide new age estimates and revised provenience information for the Liujiang human fossils, which represent one of the most complete fossil skeletons of H. sapiens in China. U-series dating on the human fossils and radiocarbon and optically stimulated luminescence dating on the fossil-bearing sediments provided ages ranging from ~33,000 to 23,000 years ago (ka). The revised age estimates correspond with the dates of other human fossils in northern China, at Tianyuan Cave (~40.8-38.1 ka) and Zhoukoudian Upper Cave (39.0-36.3 ka), indicating the geographically widespread presence of H. sapiens across Eastern Asia in the Late Pleistocene, which is significant for better understanding human dispersals and adaptations in the region.


Assuntos
Fósseis , Datação Radiométrica , Humanos , China , Cavernas , Esqueleto , História Antiga , Sedimentos Geológicos
6.
Nature ; 627(8005): 805-810, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38448591

RESUMO

Stone tools stratified in alluvium and loess at Korolevo, western Ukraine, have been studied by several research groups1-3 since the discovery of the site in the 1970s. Although Korolevo's importance to the European Palaeolithic is widely acknowledged, age constraints on the lowermost lithic artefacts have yet to be determined conclusively. Here, using two methods of burial dating with cosmogenic nuclides4,5, we report ages of 1.42 ± 0.10 million years and 1.42 ± 0.28 million years for the sedimentary unit that contains Mode-1-type lithic artefacts. Korolevo represents, to our knowledge, the earliest securely dated hominin presence in Europe, and bridges the spatial and temporal gap between the Caucasus (around 1.85-1.78 million years ago)6 and southwestern Europe (around 1.2-1.1 million years ago)7,8. Our findings advance the hypothesis that Europe was colonized from the east, and our analysis of habitat suitability9 suggests that early hominins exploited warm interglacial periods to disperse into higher latitudes and relatively continental sites-such as Korolevo-well before the Middle Pleistocene Transition.


Assuntos
Sepultamento , Migração Humana , Datação Radiométrica , Humanos , Arqueologia , Sepultamento/história , Europa (Continente) , Fósseis , História Antiga , Migração Humana/história , Reprodutibilidade dos Testes , Ucrânia , Fatores de Tempo
7.
Nature ; 626(7998): 341-346, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38297117

RESUMO

The Middle to Upper Palaeolithic transition in Europe is associated with the regional disappearance of Neanderthals and the spread of Homo sapiens. Late Neanderthals persisted in western Europe several millennia after the occurrence of H. sapiens in eastern Europe1. Local hybridization between the two groups occurred2, but not on all occasions3. Archaeological evidence also indicates the presence of several technocomplexes during this transition, complicating our understanding and the association of behavioural adaptations with specific hominin groups4. One such technocomplex for which the makers are unknown is the Lincombian-Ranisian-Jerzmanowician (LRJ), which has been described in northwestern and central Europe5-8. Here we present the morphological and proteomic taxonomic identification, mitochondrial DNA analysis and direct radiocarbon dating of human remains directly associated with an LRJ assemblage at the site Ilsenhöhle in Ranis (Germany). These human remains are among the earliest directly dated Upper Palaeolithic H. sapiens remains in Eurasia. We show that early H. sapiens associated with the LRJ were present in central and northwestern Europe long before the extinction of late Neanderthals in southwestern Europe. Our results strengthen the notion of a patchwork of distinct human populations and technocomplexes present in Europe during this transitional period.


Assuntos
Migração Humana , Animais , Humanos , Restos Mortais/metabolismo , DNA Antigo/análise , DNA Mitocondrial/análise , DNA Mitocondrial/genética , Europa (Continente) , Extinção Biológica , Fósseis , Alemanha , História Antiga , Homem de Neandertal/classificação , Homem de Neandertal/genética , Homem de Neandertal/metabolismo , Proteômica , Datação Radiométrica , Migração Humana/história , Fatores de Tempo
8.
Nature ; 625(7995): 535-539, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38200315

RESUMO

The largest ever primate and one of the largest of the southeast Asian megafauna, Gigantopithecus blacki1, persisted in China from about 2.0 million years until the late middle Pleistocene when it became extinct2-4. Its demise is enigmatic considering that it was one of the few Asian great apes to go extinct in the last 2.6 million years, whereas others, including orangutan, survived until the present5. The cause of the disappearance of G. blacki remains unresolved but could shed light on primate resilience and the fate of megafauna in this region6. Here we applied three multidisciplinary analyses-timing, past environments and behaviour-to 22 caves in southern China. We used 157 radiometric ages from six dating techniques to establish a timeline for the demise of G. blacki. We show that from 2.3 million years ago the environment was a mosaic of forests and grasses, providing ideal conditions for thriving G. blacki populations. However, just before and during the extinction window between 295,000 and 215,000 years ago there was enhanced environmental variability from increased seasonality, which caused changes in plant communities and an increase in open forest environments. Although its close relative Pongo weidenreichi managed to adapt its dietary preferences and behaviour to this variability, G. blacki showed signs of chronic stress and dwindling populations. Ultimately its struggle to adapt led to the extinction of the greatest primate to ever inhabit the Earth.


Assuntos
Extinção Biológica , Fósseis , Hominidae , Animais , Cavernas , China , Dieta/veterinária , Florestas , Hominidae/classificação , Plantas , Pongo , Datação Radiométrica , Estações do Ano , Fatores de Tempo
9.
Anthropol Anz ; 81(2): 169-181, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-37675658

RESUMO

The Subalyuk hominin remains were uncovered in 1932 in a cave of the same name in the Bükk Mountains, near the village of Cserépfalu in Borsod-Abaúj-Zemplén County, Northern Hungary. The remains represent two individuals, an adult and a young child who have been described in a few publications since their discovery, providing substantial anthropological data and general assessments of their Neanderthal affiliation. They were associated with Late Mousterian industry. Thus, the Bükk Mountains gain importance in the discussion concerning the contribution of East Central European sites to the debate on the peopling history of Europe during the Late Middle to Early Upper Palaeolithic transition. In this paper, we summarize the archaeological and chronological context of the two individuals, and publish the first direct dating results that place them among the Last Neanderthals of Central Europe.


Assuntos
Hominidae , Homem de Neandertal , Animais , Criança , Humanos , Hungria , Fósseis , Europa (Continente) , Arqueologia , Datação Radiométrica
11.
Sci Rep ; 13(1): 22119, 2023 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-38092830

RESUMO

Collagen glue has been used for nearly two centuries to consolidate bone material, although its prevalence in museum collections is only now becoming visible. Identifying and removing collagen glue is crucial before the execution of any geochemical or molecular analyses. Palaeolithic bone objects from old excavations intended for radiocarbon dating were first analysed using ZooMS (Zooarchaeology by Mass Spectrometry) to identify the animal species, however peaks characteristic of both cattle and whale were discovered. Two extraction methods for ZooMS were tested to identify the authentic animal species of these objects, which revealed that these were originally whale bone objects that had been consolidated with cattle collagen glue. This is the first time animal collagen glue has been identified in archaeological remains with ZooMS, illustrating again the incredible versatility of this technique. Another technique, Fourier Transform Infrared Spectroscopy in Attenuated Total Reflectance mode (FTIR-ATR), was also tested if it could rapidly identify the presence of collagen glue in archaeological bone material, which was not the case. Two other cleaning methods were tested to remove bone glue contamination prior to radiocarbon dating, along with two modified collagen extraction methods for ZooMS. These methods were applied to bone blank samples (FmC = 0.0031 ± 0.0002, (n = 219), 47 336 ± 277 yr BP) that were experimentally consolidated with collagen glue and to the Palaeolithic bone material (ca. 15 000 and 12 000 yr BP). The experimental bone blanks produced excellent 14C ages, suggesting the cleaning methods were successful, however the 14C ages for some of the Palaeolithic material remained too young considering their contextual age, suggesting that the collagen glue contamination had most likely cross-linked to the authentic collagen molecule. More research is needed in order to gain a deeper understanding of the occurrence and elimination of cross-linked collagen-based glues in material from museum collections.


Assuntos
Colágeno , Datação Radiométrica , Animais , Bovinos , Datação Radiométrica/métodos , Radioisótopos de Carbono/análise , Colágeno/química , Osso e Ossos/química , Arqueologia/métodos , Baleias
12.
PLoS One ; 18(11): e0293119, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37967047

RESUMO

The ancient southern Levantine city of Gezer is well-known from Egyptian, Biblical and Assyrian sources, associated with power struggles, conquests, and intriguing tales involving figures such as Milkilu and Amenhotep III, Merneptah, the Philistines, Solomon and his unidentified pharaonic father-in-law, and Shishak / Sheshonq I. Since the identity of Gezer with "Tell Jezer" is quite literally 'set in stone' by some dozen boundary inscriptions, along with impressive Bronze and Iron Age remains, research at this site provides a unique opportunity to compare text and archaeology, as well as bring to light the undocumented everyday lives of the city's inhabitants. In this endeavour, independent scientific dating is crucial for anchoring the remains chronologically. This paper presents the first substantial radiocarbon dataset and Bayesian chronological analysis for Gezer spanning the last part of the Late Bronze Age (LBA; LB IIB) through Iron Age II. The dataset derives from an essentially continuous stratigraphic sequence exposed in recent years by the Tandy expedition along the central-southern edge of the site. The results allow us for the first time to independently determine the site chronology, test the viability (from a chronological perspective) of proposed historical correlations, and contribute to debates on Philistine and Iron Age chronology.


Assuntos
Arqueologia , Bíblia , Arqueologia/métodos , Teorema de Bayes , Tempo , Datação Radiométrica/métodos
13.
J Forensic Leg Med ; 100: 102607, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37913574

RESUMO

BACKGROUND: Radiocarbon (14C), whose levels increased in the atmosphere between 1955 and 1963, accumulates in the enamel of human teeth only during the process of tooth formation and has been applied to estimate the birth year of unidentified corpses. However, enamel isolation from teeth is time-consuming and labor-intensive. Therefore, this study aimed to estimate the birth year using 14C in the crown of a single mandibular first premolar tooth. MATERIALS AND METHODS: Fourteen mandibular first premolars collected from forensic autopsies were analyzed. For nine teeth, each tooth was cut longitudinally: half of the tooth was enamel, and the other half was crown (1). For the other five teeth, the entire crown was used (2). Thereafter, the 14C concentration in each tooth was measured using accelerator mass spectrometry. RESULTS: The absolute error between the actual date of birth (DOB) and the estimated DOB was within the range of 1.0-8.8 years in the enamel of five teeth and 0.1-4.0 years in the crown halves of seven teeth (1). For the five teeth with entire crowns, the absolute errors ranged between 0.3 and 3.0 years (2). CONCLUSION: The absolute error of 14C-based year of birth estimation using the powdered crown of the mandibular first premolar teeth ranged between 0.1 and 4.0 years. Our method, which involves pulverizing an entire crown, eliminates the need for the equipment, time, and labor associated with enamel isolation. Therefore, 14C dating using powdered crowns of mandibular premolars can be useful for birth year estimation.


Assuntos
Datação Radiométrica , Coroa do Dente , Humanos , Dente Pré-Molar , Pós , Espectrometria de Massas
14.
Proc Biol Sci ; 290(2009): 20231129, 2023 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-37876197

RESUMO

The application of Zooarchaeology by Mass Spectrometry (ZooMS) on Pleistocene sites in Europe and northern Asia has resulted in the discovery of important new hominin fossils and has expanded the range of identified fauna. However, no systematic, large-scale application of ZooMS on Palaeolithic sites in East Asia has been attempted thus far. Here, we analyse 866 morphologically non-diagnostic bones from Jinsitai Cave in northeast China and Yumidong Cave in South China, from archaeological horizons dating to 150-10 ka BP. Bones from both sites revealed a high degree of collagen preservation and potentially time-related deamidation patterns, despite being located in very distinct environmental settings. At Jinsitai, we identified 31 camel bones, five of which were radiocarbon dated to 37-20 ka BP. All dated specimens correspond to colder periods of Marine Isotope Stages 3 and 2. We regard the presence of camels at Jinsitai as evidence of wild camels being a megafauna taxon targeted, most likely by early modern humans, during their expansion across northeast Asia. This large-scale application of ZooMS in China highlights the potential of the method for furthering our knowledge of the palaeoanthropological and zooarchaeological records of East Asia.


Assuntos
Camelus , Hominidae , Humanos , Animais , Espectrometria de Massas/métodos , Fósseis , China , Arqueologia/métodos , Datação Radiométrica
15.
Science ; 382(6666): 73-75, 2023 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-37797035

RESUMO

Human footprints at White Sands National Park, New Mexico, USA, reportedly date to between ~23,000 and 21,000 years ago according to radiocarbon dating of seeds from the aquatic plant Ruppia cirrhosa. These ages remain controversial because of potential old carbon reservoir effects that could compromise their accuracy. We present new calibrated 14C ages of terrestrial pollen collected from the same stratigraphic horizons as those of the Ruppia seeds, along with optically stimulated luminescence ages of sediments from within the human footprint-bearing sequence, to evaluate the veracity of the seed ages. The results show that the chronologic framework originally established for the White Sands footprints is robust and reaffirm that humans were present in North America during the Last Glacial Maximum.


Assuntos
Evolução Biológica , Hominidae , Animais , Humanos , Luminescência , América do Norte , Datação Radiométrica/métodos , New Mexico , Parques Recreativos , Pólen , Alismatales , Radioisótopos de Carbono , Sementes
16.
Sci Rep ; 13(1): 17284, 2023 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-37828091

RESUMO

We present direct evidence of early grape domestication in southern Italy via a multidisciplinary study of pip assemblage from one site, shedding new light on the spread of viticulture in the western Mediterranean during the Bronze Age. This consist of 55 waterlogged pips from Grotta di Pertosa, a Middle Bronze Age settlement in the south of the Italian peninsula. Direct radiocarbon dating of pips was carried out, confirming the chronological consistency of the samples with their archaeological contexts (ca. 1450-1200 BCE). The extraordinary state of conservation of the sample allowed to perform geometric morphometric (GMM) and paleogenetic analyses (aDNA) at the same time. The combination of the two methods has irrefutably shown the presence of domestic grapevines, together with wild ones, in Southern Italy during the Middle/Late Bronze Age. The results converge towards an oriental origin of the domestic grapes, most likely arriving from the Aegean area through the Mycenaeans. A parent/offspring kinship was also recognised between a domestic/wild hybrid individual and a domestic clonal group. This data point out a little known aspect of the diffusion of the first viticulture in Italy, and therefore in the western Mediterranean, which involved the hybridization between imported domestic varieties with, likely local, wild vines.


Assuntos
Domesticação , Vitis , Itália , Vitis/genética , Arqueologia , Datação Radiométrica
17.
Glob Chang Biol ; 29(19): 5720-5735, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37565359

RESUMO

Rapid, ongoing permafrost thaw of peatlands in the discontinuous permafrost zone is exposing a globally significant store of soil carbon (C) to microbial processes. Mineralization and release of this peat C to the atmosphere as greenhouse gases is a potentially important feedback to climate change. Here we investigated the effects of permafrost thaw on peat C at a peatland complex in western Canada. We collected 15 complete peat cores (between 2.7 and 4.5 m deep) along four chronosequences, from elevated permafrost peat plateaus to saturated thermokarst bogs that thawed up to 600 years ago. The peat cores were analysed for peat C storage and peat quality, as indicated by decomposition proxies (FTIR and C/N ratios) and potential decomposability using a 200-day aerobic laboratory incubation. Our results suggest net C loss following thaw, with average total peat C stocks decreasing by ~19.3 ± 7.2 kg C m-2 over <600 years (~13% loss). Average post-thaw accumulation of new peat at the surface over the same period was ~13.1 ± 2.5 kg C m-2 . We estimate ~19% (±5.8%) of deep peat (>40 cm below surface) C is lost following thaw (average 26 ± 7.9 kg C m-2 over <600 years). Our FTIR analysis shows peat below the thaw transition in thermokarst bogs is slightly more decomposed than peat of a similar type and age in permafrost plateaus, but we found no significant changes to the quality or lability of deeper peat across the chronosequences. Our incubation results also showed no increase in C mineralization of deep peat across the chronosequences. While these limited changes in peat quality in deeper peat following permafrost thaw highlight uncertainty in the exact mechanisms and processes for C loss, our analysis of peat C stocks shows large C losses following permafrost thaw in peatlands in western Canada.


Assuntos
Carbono , Pergelissolo , Solo , Solo/química , Carbono/análise , Canadá , Congelamento , Datação Radiométrica
18.
J Forensic Sci ; 68(4): 1372-1378, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37288938

RESUMO

In cases where human remains are unidentified because there is no initial identification hypothesis, limited contextual information, and/or poor preservation, radiocarbon (14 C) dating may be a useful tool to further assist with identification. Through measuring the amount of 14 C remaining in organic material, such as bone, teeth, nail, or hair, radiocarbon dating may provide an estimated year of birth and year of death for a deceased person. This information, may assist in, establishing whether a case of unidentified human remains (UHR) is actually of medicolegal significance and therefore, requires forensic investigation and identification. This case series highlights the application of 14 C dating to seven of the 132 UHR cases in Victoria, Australia. Cortical bone was sampled from each case and the level of 14 C was measured to provide an estimated year of death. Four of the seven cases analyzed contained the levels of 14 C consistent with an archeological timeframe, one contained a level of 14 C consistent with a modern (i.e., of medicolegal significance) timeframe, and the results for the remaining two samples were inconclusive. Applying this technique not only reduced the number of UHR cases in Victoria but also has investigative, cultural, and practical implications for medicolegal casework in general.


Assuntos
Restos Mortais , Datação Radiométrica , Humanos , Vitória , Datação Radiométrica/métodos , Radioisótopos de Carbono/análise , Osso e Ossos/química
19.
Sci Adv ; 9(23): eadd3761, 2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37294766

RESUMO

In the past decade, marine geophysical observations have led to the discovery of thin channels at the base of oceanic plates with anomalous physical properties that indicate the presence of low-degree partial melts. However, mantle melts are buoyant and should migrate toward the surface. We show abundant observations of widespread intraplate magmatism on the Cocos Plate where a thin partial melt channel was imaged at the lithosphere-asthenosphere boundary. We combine existing geophysical, geochemical, and seafloor drilling results with seismic reflection data and radiometric dating of drill cores to constrain the origin, distribution, and timing of this magmatism. Our synthesis indicates that the sublithospheric channel is a regionally extensive (>100,000 km2) and long-lived feature that originated from the Galápagos Plume more than 20 Ma ago, supplying melt for multiple magmatic events and persisting today. Plume-fed melt channels may be widespread and long-lived sources for intraplate magmatism and mantle metasomatism.


Assuntos
Datação Radiométrica , Vírion
20.
J Hum Evol ; 178: 103344, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36947893

RESUMO

Chuandong Cave is an important Late Paleolithic site because it documents the early appearance of bone tools in southern China. We used the single-aliquot regenerative-dose protocol for optically stimulated luminescence dating to improve the precision of the chronology for the Chuandong Cave sedimentary sequence. The age of each layer was determined using a Bayesian modeling approach which combined optically stimulated luminescence ages with published AMS 14C dates. The results showed that Layer 10 began accumulating since 56 ± 14 ka and provides the upper age limit for all artifacts from the sequence. Bone awl tools from Layer 8, the earliest grinding bone tools in this site, were recovered within sediments between 40 ± 7 ka and 30 ± 4 ka. Layer 8 also indicates the appearance of modern humans in the Chuandong Cave sequence. Layers 4-2, ranging from 15 ± 3 ka until 11 ± 1 ka and including the Younger Dryas period, contain a few bone awls and an eyed bone needle. The shift from bone awls to eyed bone needles in the Chuandong Cave sequence indicates that modern humans adapted to the changing climate of southern China. We conclude that modern human behavior in bone tools appeared in southern China as early as 40 ± 7 ka, became more sophisticated during the Last Glacial Maximum, and spread more widely across southern China during the Younger Dryas.


Assuntos
Hominidae , Animais , Humanos , Teorema de Bayes , Cavernas , Osso e Ossos , China , Datação Radiométrica , Arqueologia , Fósseis
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