Electron Spin Resonance (ESR) Dating in Karst Environments

Electron spin resonance (ESR) dating has been developed for many materials, including hydroxyapatite in enamel, bone, and some fish scales, aragonite and calcite in travertine, molluscs, and calcrete, and quartz from ash, which have many potential applications in karst settings. Although the complexity of the signals in some materials has hampered routine application, research is solving these problems to make the method even more widely applicable. When tested against other dating tech­niques, age agreement has usually been excellent. Generally, the most reliable applications seem to be tooth enamel, some mol­lusc species, calcite deposits, and quartz minerals. ESR dating uses signals resulting from trapped charges created by radia­tion in crystalline solids. Ages are calculated by comparing the accumulated dose in the dating sample with the internal and external radiation dose rates produced by natural radiation in and around the sample. For fossils and authigenic minerals, no zeroing is necessary to obtain accurate ages. In sediment which contains reworked mineral clasts, ESR can be used to date the age of the mineral grain itself if it was not zeroed during ero­sion. For dating the sedimentation age, however, ESR signals must have been zeroed in order to give the correct age. High pressure, heating, and in some minerals, light exposure and grinding can zero an ESR signal, but some like hydroxyapatite have very high stability at surface temperatures. For materi­als that absorb uranium (U) during their burial history, such as teeth, bones, or mollusc shells, the age calculation considers their U uptake by cross calibrating with U series or U/Pb dat­ing or by assuming different uptake models. Some difficulties in calculating the external dose rate can be overcome by ap­plying the ESR isochron method, in which the sample acts as its own dosimeter. In open-air karst environments, changes in the external dose rate due to altered sediment cover, and hence, changing cosmic dose rates, need to be modelled. For all karst environments, sedimentary water concentration and mineralogical variations with time also need to be considered. Many ESR applications are currently used in karst settings, but several more are also possible

Ocena vlage v mlajšepleistocenskem kraškem okolju: Paleoklima in paleomikrookolje v jami Divje babe I, Slovenija / Assessing Humidity in an Upper Pleistocene Karst Environment: Palaeoclimates and Palaeomicroenvironments at the Cave Divje babe I, Slovenia

V članku je prikazan nov sedimentološki-klimatski model za razlago avtohtonih klastičnih sedimentov v mlajšepleistocenskem najdišču Divje babe I v Sloveniji. Analizirani sedimenti pripadajo kisikovi izotopski stopnji 1, 3 in 5 (OIS 1, OIS 3, OIS 5). Poudarek analize je na padavinah, ki smo jih razložili na podlagi količine avtigenih strukturnih agregatov v sedimentih. Ugotovitve smo podprli s kvantitativno analizo reliefno korodiranih klastov, ki pomenijo korozijo jamskega svoda, in izjedkanih kosti, ki pomenijo korozijo v jamskih tleh. Raziskali smo tudi odnos med klimo in jamskim medvedom ter neandertalcem in klimo, in sicer na podlagi množičnih fosilnih ostankov ter najdb artefaktov. Vse analize smo naredili na podlagi trodimenzionalnega vzorčenja, tj. v horizontalni in vertikalni smeri. Vzorčili smo 65 profilov na površini 65 m2. Vsak profil je imel 35 arbitrarnih stratigrafskih enot (režnjev) s podatki o agregatih, izjedkanih kosteh, fosilnih ostankih in artefaktih. Pri razlagi sedimentnih karakteristik, ki nakazujejo klimatske parametre, smo dosledno upoštevali holocenske standarde za najdišče. Ugotovili smo, da je bila klima v OIS 3 hladnejša in bolj vlažna kot v OIS 1 in OIS 5. Na klimatsko spremembo v OIS 3 so se z večjim obiskom jame odzvali ljudje in živali, vendar ne hkrati. Sprememba klime se je na mikrolokaciji jame domnevno pokazala predvsem v podaljšanem trajanju snežne odeje. The article presents a new sedimentary-climatic model for explaining autochthonous clastic sediment in the Upper Pleistocene site, Divje babe I, Slovenia. The sediment analysed here was deposited during Oxygen Isotope Stages 1, 3 and 5 (OIS, OIS 3, OIS 5). The stress is on precipitation, which we explained on the basis of the quantity of authigenic structural aggregates in the sediment. We supported the results with quantitative analysis of clasts with etched surface, which represent corrosion of the cave ceiling, and etched bones, which represent corrosion on the cave ground. We also analysed the relation between climate and cave bears, and Neanderthals and climate, on the basis of mass fossil remains and finds of artefacts. All analyses were made on the basis of three-dimensional sampling, i.e., in horizontal and vertical directions. We sampled 65 profiles over an area of 65 m2. Each profile had 35 arbitrary stratigraphic units (splits) with data on aggregates, etched bones, fossil remains and artefacts. In explaining the sediment characteristics that point to climatic parameters, we consistently took into account the Holocene standards for the site. We found that the climate in OIS 3 was colder and damper than in OIS 1 and OIS 5. People and animals responded to the climatic changes in OIS 3 with more visits to the cave, but not at the same time. The climatic change was presumably reflected in the microlocation of the cave mainly by the longer duration of snow cover.  

Morfometrična in kronostrtatigrafska analiza ter paleoklimatska razlaga jamskih sedimentov v Divjih babah I, Slovenija

New ESR dates coupled with morphometric analyses of the clastic sediments and diagenetic aggregates were used to determine sedimentation rates, as well as relative humidity and especially paleotemperatures during sediment formation for the Palaeolithic deposits at Divje babe I (Slovenia). Sediment was analyzed for post-depositional frost weathering (cataclasis or congelifraction), pre- depositional corrosion on the ancient cave walls and aggregate formation. Paleotemperature determinations were verified by comparing with palynlogical determinations. In comparing the Divje babe I paleoclimatic curve with global d18O and palynological paleoclimatic records, the Palaeolithic sequence at Divje babe I correlates well with Dansgaard-Oeschger (DO) Events (= pollen Interstadials) in Oyxgen Isotope Stage (OIS) 3 to OIS 5e inclusive. Layer 8, which hosted the purported flute correlates with the DO Event 14 (= Moershoofd and Glinde Interstadials) within OIS 3. This study represents the first attempt to directly correlate climatostratigraphic features in a Slovenian cave with global paleoclimatic events, and hence with other Palaeolithic sites.Na podlagi novih datacij ESR in analize klastičnih sedimentov smo ocenili relativno paleotemperaturo, vlago in hitrost sedimentacije v času nastajanja sedimentov v profilu paleolitskega najdišča Divje babe I (Slovenija). Analiza sedimentov temelji na izbranih morfoloških in drugih lastnostih klastičnih sedimentov. Relativna ocena paleotemperature je interno preverjena s pelodno analizo. Kronostratigrafske in morfometrične izsledke smo primerjali z globalnimi paleoklimatskimi zapisi (?18O in pelod) v jedrih ledu in globokomorskih ter terestričnih sedimentov. Na podlagi dobre primerljivosti smo kronološko mesto domnevne musterjenske piščali postavili v Dansgaard-Oeschgerjev dogodek 14 (= Interstadial Moershoofd in Glinde) v OIS 3, mesto ostalih najdb pa od vključno Dansgaard-Oeschgerjevega dogodka 8 (= Interstadial Les Cottés in Denekamp) v OIS 3 do vključno Interglaciala (OIS 5e) v globalni kronologiji zadnjega glacialno-interglacialnega ciklusa. V Sloveniji, deželi klasičnega krasa, je to prvi poskus direktne primerjave klimatokronologije paleolitskega jamskega najdišča z globalno klimatokronologijo in preko nje s paleolitskimi jamskimi najdišči v drugih kraških regijah v zahodni Evropi

The latest steppe mammoths (Mammuthus trogontherii (Pohlig)) and associated fauna on the Late Middle Pleistocene steppe at Nosak, Kostolac Basin, Northeastern Serbia

In 2012, bones and tusks of mammoths and remains of other large mammals scattered in a line 130 m long have been discovered in the loess deposits at the Nosak mound in the Kostolac Basin (Northeastern Serbia). Preliminary analyses indicate that remains come from Mammuthus trogontherii, Equus ferus mosbachensis and Cervidae indet. Steppe mammoth remains originate from at least four individuals, three adults, and one juvenile. They include the largest steppe mammoth tusks ever reported. The mammalian remains were mostly found disarticulated, except for few articulated skeleton elements. Individual bones and teeth were encased within thick carbonate concretions. From their composition, morphology, and manner of formation, these carbonate concretions resemble the characteristic "loess dolls" that form in loess. Bones were exposed to subaerial weathering for some time before burial. Some damage on the bones indicates biogenic agents of their fragmentation and dispersal. Animals were probably attracted to the spot by a water source in the vicinity, such as a spring or intermittent stream. The bones and teeth accumulated at a single level within the loess likely deposited in MIS 6, just above the upper of two paleosols formed during MIS 7. A sample from a mammoth molar plate has been ESR dated at 192 +/- 5 ka, correlating with the very early MIS 6, near the MIS 6/7 boundary. This makes the Nosak mammoth the most recent occurrence of steppe mammoths in Europe, and the sole find dated to MIS 6

Sedimentary Dosimetry for the Saradj-Chuko Grotto: A Cave in a Lava Tube in the North-Central Caucasus, Russia

Karst caves host most European Paleolithic sites. Near the Eurasian-Arabian Plate convergence in the Caucasus’ Lower Chegem Formation, Saradj-Chuko Grotto (SCG), a lava tube, contains 16 geoarchaeologically distinct horizons yielding modern to laminar obsidian-rich Middle Paleolithic (MP) assemblages. Since electron spin resonance (ESR) can date MP teeth with 2–5% uncertainty, 40 sediment samples were analyzed by neutron activation analysis to measure volumetrically averaged sedimentary dose rates. SCG’s rhyolitic ignimbrite walls produce very acidic clay-rich conglomeratic silts that retain 16–24 wt% water today. In Layers 6A-6B, the most prolific MP layers, strongly decalcified bones hinder species identification, but large ungulates inhabited deciduous interglacial forests. Unlike in karst caves, most SCG’s layers had sedimentary U concentrations >4 ppm and Th, >12 ppm, but Layer 6B2 exceeded 20.8 ppm U, and Layer 7, >5 ppm Th. Such high concentrations emit dose rates averaging ~1.9–3.7 mGy/y, but locally up to 4.1–5.0 mGy/y. Within Layer 6, dose rate variations reflect bone occurrence, necessitating that several samples must be geochemically analyzed around each tooth to ensure age accuracy. Coupled with dentinal dose rates up to 3.7–4.5 mGy/y, SCG’s maximum datable ages likely averages ~500–800 ka

ESR Dating Ungulate Teeth and Molluscs from the Paleolithic Site Marathousa 1, Megalopolis Basin, Greece

At 37°24′ N 22°8′ E, the Megalopolis Basin lies in the central Peloponnese Peninsula, southwestern Greece. In the Megalopolis Basin at ~350 m amsl, the Paleolithic site, Marathousa 1, sits within a palustrine/lacustrine clastic package between Lignite Seams III and II, that both likely correlate with interglacial periods. At Marathousa 1, immediately below Lignite Seam III, lies a clayey-silty sand layer with a horizon rich in molluscs ranging from ~20–40 cm thick. About 0.8–1.3 m below the shell-rich horizon (SRH), lacustrine silty to muddy sands rich in organic matter yielded Paleolithic lithic artefacts associated with Middle Pleistocene fauna, some with cut marks and possible bone knapping, found within palustrine/lacustrine clastic deposits. Since ESR (electron spin resonance) can date teeth and molluscs aged >2 Ma, two bivalve samples, AM66 and AM65, five subsamples from a cervid molar, AT39, and one subsample from another cervid molar, AT68, were independently dated by ESR from Marathousa 1. To calculate the ages, time-averaged cosmic and time- and volumetrically-averaged sedimentary dose rates were calculated using past water depths and sedimentation rates as determined from paleontological and geological criteria. Found in the SRH in Layer UA2, AM66 and AM65 averaged 488 ± 37 ka, which correlates with MIS 13a. Because the bivalves sat stratigraphically above the artefacts and mammalian fossils, their ages constrain the ESR ages for the teeth deposited below. Lying on the unconformity at the base of Layer UA3c with UA4, and its correlative unconformity at the Layer UB4c/UB5 boundary, sat the dated teeth from large mammals. Because the bones in the Palaeoloxodon antiquus skeleton lay in quasi-anatomical association, the likelihood for fossil reworking on the Layer UB3c/UB4 surface is low. Isochron analysis suggests that using a U uptake model with p = 2 provides the most accurate ages for AT39. With p = 2, AT39 dates to 503 ± 13 ka, while AT68 dates to 512 ± 34 ka. Nonetheless, two to three more teeth and molluscs should be dated to confirm these ages, when more samples suitable for ESR dating are found. Both tooth ages correlate well with early MIS 13, an interglacial period with cooler mean global temperatures compared to MIS 11 or 9. Assuming that the archaeological site formed in one event, rather than as a palimpsest, the data suggest that hominins processed elephant and other faunal carcasses along the shores of a shallow lake or marsh in the Megalopolis Basin at 503 ± 12 ka. Between the two horizons dated here, their sedimentation rate averaged 4.8 ± 1.8 to 7.8 ± 2.9 cm/ka

The geology and morphology of the Antakya Graben between the Amik Triple Junction and the Cyprus Arc

In southeastern Turkey, the NE-trending Antakya Graben forms an asymmetric depression filled by Pliocene marine siliciclastic sediment, Pleistocene to Recent fluvial terrace sediment, and alluvium. Along the Mediterranean coast of the graben, marine terrace deposits sit at different elevations ranging from 2 to 180 m above present sea level, with ages ranging from MIS 2 to 11. A multisegmented, dominantly sinistral fault lying along the graben may connect the Cyprus Arc in the west to the Amik Triple Junction on the Dead Sea Fault (DSF) in the east. Normal faults, which are younger than the sinistral ones, bound the graben's southeastern margin. The westward escape of the continental Iskenderun Block, delimited by sinistral fault segments belonging to the DSF in the east and the Eastern Anatolian Fault in the north caused the development of a sinistral transtensional tectonic regime, which has opened the Antakya Graben since the Pliocene. In the later stages of this opening, normal faults developed along the southeastern margin that caused the graben to tilt to the southwest, leading to differential uplift of Mediterranean coastal terraces. Most of these normal faults remain active. In addition to these tectonic movements, Pleistocene sea level changes in the Mediterranean affected the geomorphological evolution of the area

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research