TL Ages Research Articles

Variability in newborn telomere length is explained by inheritance and intrauterine environment

BackgroundTelomere length (TL) and its attrition are important indicators of physiological stress and biological aging and hence may vary among individuals of the same age. This variation is apparent even in newborns, suggesting potential effects of parental factors and the intrauterine environment on TL of the growing fetus.MethodsAverage relative TLs of newborns (cord tissue, N = 950) and mothers (buffy coat collected at 26–28 weeks of gestation, N = 892) were measured in a birth cohort. This study provides a comprehensive analysis of the effects of heritable factors, socioeconomic status, and in utero exposures linked with maternal nutrition, cardiometabolic health, and mental well-being on the newborn TL. The association between maternal TL and antenatal maternal health was also studied.ResultsLonger maternal TL (β = 0.14, P = 1.99E−05) and higher paternal age (β = 0.10, P = 3.73E−03) were positively associated with newborn TL. Genome-wide association studies on newborn and maternal TLs identified 6 genetic variants in a strong linkage disequilibrium on chromosome 3q26.2 (Tag SNP-LRRC34-rs10936600: Pmeta = 5.95E−08). Mothers with higher anxiety scores, elevated fasting blood glucose, lower plasma insulin-like growth factor-binding protein 3 and vitamin B12 levels, and active smoking status during pregnancy showed a higher risk of giving birth to offspring with shorter TL. There were sex-related differences in the factors explaining newborn TL variation. Variation in female newborn TL was best explained by maternal TL, mental health, and plasma vitamin B12 levels, while that in male newborn TL was best explained by paternal age, maternal education, and metabolic health. Mother’s TL was associated with her own metabolic health and nutrient status, which may have transgenerational effects on offspring TL.ConclusionsOur findings provide a comprehensive understanding of the heritable and environmental factors and their relative contributions to the initial setting of TL and programing of longevity in early life. This study provides valuable insights for preventing in utero telomere attrition by improving the antenatal health of mothers via targeting the modifiable factors.Trial registrationClinicalTrials.gov, NCT01174875. Registered on 1 July 2010

Effects of Density Reduction on Age‐Specific Growth of Stream‐Dwelling Brown Trout

AbstractDensity‐dependent growth has been well documented among stream‐dwelling Brown Trout Salmo trutta populations. In Spearfish Creek, South Dakota, biomass of adult Brown Trout (>200 mm) is about three times greater than that reported for similar Black Hills streams, whereas the mean length of adult fish is about 30% less. Here, we evaluate density reduction as a management tool for improving the growth rate of stream‐dwelling Brown Trout. We compared age‐specific growth of wild Brown Trout in stream sections receiving 50% reductions in fish abundance (removal sections) to that of fish in sections containing natural densities (control sections). Annual growth in length and weight of older Brown Trout (age > 2) was greater in removal sections compared to control sections, particularly among fish between 230 and 280 mm TL (ages 3–4). We attribute the growth response to constraints imposed by food availability and the strong feeding hierarchies, characteristic of larger (older) Brown Trout. Data collected from PIT‐tagged fish that were recaptured 2 years after fish removal efforts revealed that growth responses owing to density reduction likely did not extend beyond 1 year. Nonetheless, among cohorts that showed improved growth after the first year, we found that their growth advantage was sustained into the second year. At removal sections, age‐3 and older Brown Trout that experienced greater growth after 1 year were larger than fish from control sections 2 years later at age 5 and older. Identification of cohort(s) for which density‐dependent growth is most pronounced could help to focus efforts on targeted reduction of specific fish sizes/ages that minimize the cost–benefit ratio of fish removal efforts.

The loess section in Wąchock as the key site of Vistulian loesses and palaeosols in the Holy Cross Mountains (Poland)

The Wąchock section (N part of the Holy Cross Mountains) is bipartite, with a sub-loess lower part and a loess upper part. The sub-loess part lying on Lower Triassic sandstones includes fluvial, glacial and ice-dammed lake deposits, TL-dated at 352 ky BP to 157 ±23 ky BP. They represent the Mazovian (MIS 11) (Zbojnian?, MIS 9?) Interglacial and the Odranian Glaciation (MIS 6). The upper part comprises loesses intercalated with palaeosols, which reach a total thickness of 9 m and have TL ages at 148 ±23 ky BP to 15.8 ±8 ky BP. This part of the succession begins with horizon B of a brown soil from the Eemian Interglacial (MIS 5e) with an interstadial black soil from the oldest Vistulian (MIS 5c). Four younger loess horizons from the middle and younger Vistulian occur above; loesses with arctic and tundra palaeosols correspond to younger isotope stages (MIS 5b–MIS 2). The loess and palaeosol horizons distinguished in Wąchock were correlated with loess sections in Poland (Zwierzyniec and Polanow Samborzecki) and western Ukraine (Kolodiiv 3), showing large similarities of both loesses and palaeosols. Due to this, the Wąchock site is proposed as a one of key sections for Vistulian loess sequences not only in the Holy Cross Mts. region but also in Central Europe. Palaeomagnetic studies of the Wąchock loesses have registered palaeomagnetic inclinations with values lower than the average values expected in this locality (63°).

Reassessing the timeframe of Upper Palaeolithic deposits in the Ceahlău Basin (Eastern Carpathians, Romania): Geochronological and archaeological implications

Abstract The Pleistocene deposits capping fluvial terraces in the Bistrita valley (Eastern Carpathians, Romania) host a high density of Upper Palaeolithic (UP) settlements, rendering this area a type-region for Late Pleistocene cultural evolution in eastern Romania and beyond. Despite its archaeological significance, site formation, palaeoenvironmental contextualisation and chronostratigraphy are still insufficiently resolved to draw a consistent picture of UP cultural dynamics. In the frame of recent excavations at the sites Bistricioara-Lutarie I and III (BLI, BLIII), we aimed at establishing a comprehensive multi-method (TL on heated flints, OSL on sedimentary quartz, radiocarbon dating of charcoal) chronology of the pluristratified archaeological records contained in the loess-like sediments on the lower and middle terraces of the Bistrița river. Therefore, new chronometric data are reviewed in conjunction with OSL ages and radiocarbon dates of a precursor study (Trandafir et al., 2015). Multi-emission TL ages of four heated flints, OSL sediment ages and radiocarbon dates are consistent within 2σ throughout the investigated archaeological profiles and allow a much more precise chronological framing of the identified lithostratigraphic units within the last glacial cycle. However, the silt-sized and sand-sized quartz fractions of a luminescence sample do not always produce identical results at 1σ. Numerical ages and field observations indicate that the geological record reaches back to Marine Isotope Stage 5 and is preserved on a lower terrace. Depending on their location, the investigated terrace cover beds represent genetically independent geomorphological units, and up to three palaeosols (cambisols) developed in the cover beds, of which at this stage of research only the youngest (PS1) can be traced unequivocally within all profiles. In archaeological terms, the new chronological framing confirms that the currently identified cultural layers belong to the Late Gravettian (28–25 ka BP), and to several Epigravettian stages (24–15 ka BP), leaving limited chronological space for the previously suspected Aurignacian presence at BLI and at other settlements nearby.

Investigation into the OSL and TT-OSL signal characteristics of ancient (>100 ka) Tasmanian aeolian quartz and its utility as a geochronometer for understanding long-term climate-driven landscape change

The luminescence characteristics and age estimates of nine samples of aeolian quartz are reported from the Southwood B section in the Arve Valley of southern Tasmania, Australia. New OSL and TT-OSL ages obtained from the deepest Tasmanian aeolian section found so far, the Southwood B section (>6 m deep), range from 20 ka (MIS 2) to 180 ka (MIS 6). Here we test two previously published TT-OSL protocols on our samples: the protocol of Brown and Forman (2012) and a protocol modified from Stevens et al. (2009). Congruencies between our TT-OSL chronology, OSL chronology and previously published TL ages suggest that the modified Stevens et al. (2009) protocol is the most robust for these samples. Furthermore, detailed comparisons of the laboratory data for TL, OSL, and TT-OSL samples provide information on their signal characteristics, their utility as chronometers, and give insight into the bleaching histories of the deposits. All OSL and TT-OSL ages obtained from the Southwood B section fall below the upper dating limits of these signals, which are reported to be as high as ∼280 ka and ∼570 ka, respectively. The TT-OSL signal saturates at doses that are two to three times those of the OSL signal, and may not only provide a chronology for sediments deposited during MIS 5, but also, according to the saturation limits, for any preserved sediments that accumulated during MIS 6 through to MIS 15. TT-OSL ages from older sediments in this region, combined with further stratigraphic studies have the potential to determine the climatic history of Tasmania over multiple glacial periods.

Alluvial fan sediments and surface ages resulting from differing climatic and tectonic conditions in Star Valley, Wyoming, USA

Alluvial fans occur in all climatic and tectonic environments. However, most descriptions of fan features and sediments have focused on arid and semiarid regions. This paper describes the sediments and soil ages on 63 alluvial fans in a subhumid climate (mean annual precipitation of 45–52 cm). SSURGO soil data were merged with geologic and topographic data in the ArcMap© GIS platform to develop a series of maps showing variations across fan surfaces in sediment textures and surface stability ages. Particle size data (percent cobble and percent total gravel) from the upper 150 cm of sediments cluster into six textural groups that are aligned along a trend of decreasing gravel percentage (decreasing stream capacity) and decreasing cobble percentage (decreasing stream competency). The groups of higher cobble and gravel percentages extend from fan apex to toe in both the shallow (<50 cm depth) and deeper (>100 cm depth) layers with groups of lower cobble and gravel percentage occurring along fan margins in the shallow (<50 cm depth) layer. The thickness of B and Bt horizons from representative soil profiles were used to calculate proportional soil ages based on 10Be residence times in loessial Bt horizons and correlation of gravelly fan soils to similar gravelly soils on nearby Pinedale outwash. This approach identified six stability episodes since the end of the Bull Lake beginning at ~100 ka, ~38 ka, ~27 ka, ~16 ka, ~10 ka, and <2 ka. The proportional soil ages correlate closely with fan chronologies constrained by TL and OSL ages in nearby areas. Soil ages and sediment textural groups differed between fan populations along the mountain front with active faulting and those along the stable mountain front. Fan stability surfaces older than 16 ka are preserved only at fault termini. Holocene faulting resulted in fans with (1) coarser sediments, (2) younger sediments, (3) progressive onlap of younger sediments, (4) the absence of relic fan surfaces, landslides and colluvium at the mountain front, and (5) the onlap of alluvial fans onto the floodplain of the axial stream. Sediment pulses related to individual fault events could not be definitively identified because of concurrent climatic changes. The study demonstrates that both climatic and tectonic conditions influence sediment textures and fan surfaces ages.

Using DRAC in complex geometries - TL dating of heated flints from Taibeh, Jordan

Abstract The archaeological site of Taibeh located south of Wadi Musa, Jordan, incorporates at least two, maybe even five, successive layers associated with the Late Ahmarian, also known as Masraqan, technocomplex. The Masraqan is elsewhere connected with the beginning of the intensive use of plant food and with permanent settlements. Taibeh could be the first site to present as much as 5 successive layers of this cultural unit. The Masraqan is relatively well constrained in time, usually dated between 18 and 25 ka BP. A series of heated flints was collected at Taibeh to be dated using TL. Two informations are required for the estimation of a TL age: the equivalent dose ( D e ) which is the dose accumulated in the flint since it had been heated, and the dose rate ( D ˙ ) to which the flint is exposed during the burial time. The D e estimation was done applying two different protocols, and both produced consistent results. The D ˙ estimation was realised using a modified version of DRAC (Durcan et al., 2015) which allows to use different radio-element concentrations for the flints and the surrounding sediment.

ESR/U-series chronology of early Neanderthal occupations at Cova Negra (Valencia, Spain)

The spatiotemporal repartition of Neanderthal populations throughout the late Middle and early Upper Pleistocene is of great interest for our understanding of human evolution. Establishing a reliable chronology for human-bearing layers from prehistoric sites is thus essential for the study of Neanderthal population dynamics prior to modern human arrival in Europe. Cova Negra (Valencia, Spain) is one of the richest sites documenting Neanderthal fossil bones in the Iberian Peninsula (Arsuaga et al., 1989, 2007; Villaverde et al., 2014). The stratigraphic sequence includes 15 Middle Palaeolithic layers. Among them, four were dated by the ESR/U-series dating method on enamel from six herbivore fossil teeth. Equivalent doses were obtained using the additive dose method on multi-aliquots. U-content, 234U/238U and 230Th/234U isotopic ratios were measured using ICP-QMS. Results indicate that dental tissues from two out of six analysed teeth underwent U leaching during burial. Thus, it does not allow the calculation of US-ESR (U-series-ESR, Grün et al., 1988) ages for these samples. However, ages calculated using AU model (Accelerating Uptake, Shao et al., 2012) are discussed together with biochronological data and previous absolute ages obtained for the archaeological sequence. Age results indicate that Neanderthals occupied Cova Negra during MIS 8 to 6, between 273 ± 26 ka and 146 ± 34 ka. These results suggest that human occupation took place at the end of the Middle Pleistocene, and hence it is older than proposed by previous TL ages obtained on sediments (Arsuaga et al., 2007). By contrast, our ESR/U-Th ages suggest that Neanderthals were present in the cave 100 ka earlier than initially proposed, in agreement with TL ages obtained on burnt flint (Villaverde et al., 2014). This implies that the Cova Negra human specimens could represent one the earliest occurrences of Neanderthal presence in the Iberian Peninsula.

Optical dating of eolian deposits since the last interglacial along the northern margin of the Chinese Loess Plateau

Understanding the chronology of eolian sand-loess-paleosol sequences along the northern margin of the Chinese Loess Plateau (CLP) is crucial for comprehending climate change and the advance and retreat of the adjacent Mu Us desert. In this study, a sand-loess-soil sequence from the northern margin of the CLP was studied by applying the single aliquot regenerative (SAR) protocol to quartz grains, and the multi-elevated-temperature post-IR IRSL (MET-pIRIR) protocol to K-feldspar grains. For equivalent dose (De) determination, 63–90 μm quartz and K-feldspar grains were used. Our results indicate that the MET-pIRIR ages of K-feldspar grains in this sequence range from 94.4 ± 7.0 ka to 148.3 ± 13.3 ka for the last interglacial paleosol (S1); for the upper part of the section, quartz-based SAR-OSL dating was used, yielding ages spanning from 5.8 ± 0.4 ka to 35.9 ± 4.1 ka. After cross-checking these results with previously-reported isochron OSL and TL ages, the reliability of the MET-pIRIR protocol when applied to the last interglacial paleosol was confirmed. Based on a new OSL chronology of the Shimao profile, the studied eolian deposits can be broadly correlated with the last glacial-interglacial cycle, but their dating also points to sedimentary hiatuses occurring at 94.4 ka, 35.9 ka and 5.8 ka, due most probably to strong wind erosion caused by intensified cold-dry winter monsoonal circulations during the last glacial maxima.

Origins of late- Pleistocene coastal dune sheets, Magdalena and Guerrero Negro, from continental shelf low-stand supply (70–20 ka), under conditions of southeast littoral- and eolian-sand transport, in Baja California Sur, Mexico

Abstract Shallow morpho-stratigraphic sections (n = 11) in each of two large coastal dune sheets including the Magdalena (7000 km2) and Guerrero Negro (8000 km2) dune sheets, from the Pacific Ocean side of Baja California Sur, Mexico, have been analyzed for dune deposit age. The shallow morpho-stratigraphic sections (∼2–10 m depth) include 11 new TL and 14C ages, and paleosol chronosequences, that differentiate cemented late Pleistocene dune deposits (20.7 ± 2.1 to 99.8 ± 9.4 ka) from uncemented Holocene dune deposits (0.7 ± 0.05 to at least 3.2 ± 0.3 ka). Large linear dune ridges (5–10 m in height) in the dune sheet interiors trend southeast and are generally of late Pleistocene age (∼70–20 ka). The late Pleistocene dune deposits reflect eolian transport of marine sand across the emerged continental shelf (30–50 km southeast distance) from low-stand paleo-shorelines (−100 ± 25 m elevation), which were locally oriented nearly orthogonal to modeled deep-water wave directions (∼300° TN). During the Holocene marine transgression, onshore and alongshore wave transport delivered remobilized shelf-sand deposits to the nearshore areas of the large dune sheets, building extensive barrier islands and sand spits. Submerged back-barrier lagoons generally precluded marine sand supply to dune sheet interiors in middle to late Holocene time, though exceptions occur along some ocean and lagoon shorelines. Reactivation of the late Pleistocene dune deposits in the dune sheet interiors lead to generally thin (1–3 m thickness), but widespread, covers of Holocene dune deposits (0.41 ± 0.05 to 10.5 ± 1.6 ka). Mechanical drilling will be required to penetrate indurated subsoil caliche layers to reach basal Pleistocene dune deposits.

A32 1 万年より若い火山岩の年代測定例としての雲仙火山眉山岩体の TL 年代

A32 1 万年より若い火山岩の年代測定例としての雲仙火山眉山岩体の TL 年代

A02 TL 年代測定による雲仙火山の層序と二次堆積物の時代及び供給源の推定

A02 TL 年代測定による雲仙火山の層序と二次堆積物の時代及び供給源の推定

The Don formation, Toronto, Canada: a record of the sangamonian interglacial and early wisconsinan (warm part of MIS 5e to a MIS 5 cold substage)

Regarded as a reference unit of the Sangamonian Interglacial in North America, the Don Formation was deposited however during a longer interval of time, including the interglacial climatic optimum of MIS 5e followed by an erosive and cool phase (intra-MIS 5e or MIS 5d), a boreal phase with a fir forest (late MIS 5e transition or MIS 5c), erosive episodes and the early part of a cold stadial (MIS 5d or MIS 5b). From the planar geometry of the beds exposed at the former Don Valley Brickyard in Toronto, the formation comprises five continuous allozones with lateral variations of thickness. Each allozone corresponds to dominant conditions of sedimentation in a shoreface of Lake Coleman within a limited accommodation space. Allozone D2 is correlated to other interglacial units of Eastern Canada, with ages between 128 and 115 ka. The interglacial climatic optimum is interrupted in the area by two cool events, the first one similar to the Tunturi event of Finland, the second one probably related to a Greenland Stadial. The heterogeneous upper Allozone D5 was deposited in shallow waters when a Northern Boreal Forest prevailed in the watershed. This zone is correlated to the Deschaillons Varves of the central St. Lawrence River Valley, deposited prior to the first regional Wisconsinan glacial advance in the central St. Lawrence River Valley and the resulting glacial Lake Scarborough Formation. From the 80 ka minimalU/Th age of the Deschaillons Varves and the 98 ± 8 ka TL age of the later marine La Perade Clay, Allozone D5 was deposited during the beginning of one of the cold episodes of MIS 5.

Dating Quaternary raised coral terraces along the Saudi Arabian Red Sea coast

Late Pleistocene raised coral reef terraces form extensive outcrops up to 5km wide along the Saudi coast. Porites coral were dated using U/Th while clastic sediment from Jeddah was dated using thermoluminescence. The pooled mean age for the coral samples is 121.5±0.2ka suggesting MIS 5e, even for the uplifted 16–20m high terrace in the north at Haql. In Jeddah the MIS 5e back-reef succession is overlain by fluvial sediment that gave a TL age of 66±13ka. The structure and faunal composition of the coral terraces suggests that they accumulated in broad shallow embayments following the last interglacial transgression. The consistent elevation of these terraces suggests that the central and southern Saudi coast has been tectonically stable for at least the past 125,000years and the coral reef terraces (at 3.5–5.5m elevation) are consistent with the MIS 5e sea level high-stand that peaked at 6–9m above present sea level. The Saudi coastal coral terrace north of Duba shows progressive uplift to 16–20m near Haql since 108–120ka as a result of ongoing transform faulting in the Gulf of Aqaba.

Larval distribution pattern of Muraenesox cinereus (Anguilliformes: Muraenesocidae) leptocephali in waters adjacent to Korea

To understand the transport and recruitment processes of the daggertooth pike conger, Muraenesox cinereus, in the marginal seas of East Asia, we investigated the distribution pattern, estimated spawning areas and periods, and recruitment mechanisms of M. cinereus, based on 51 individuals of leptocephali collected from Korean waters during 2010–2014. Back-calculated hatching dates, determined from the daily incremental growth rates of the otoliths, indicated that the spawning period for M. cinereus was during July–September. The size range of M. cinereus leptocephali collected offshore of Jeju Island and southeast of the Korea-Japan intermediate zone was 16.6–20.9 mm TL (age, 18–23 d). We hypothesize that one of the spawning grounds of M. cinereus is located offshore in the East China Sea. In Korean waters, the ages and body lengths of M. cinereus leptocephali increased northward from latitude 31°30′N to 34°40′N, with metamorphosis occurring at latitude 34°40′N. Therefore, we surmised that the hatched preleptocephali of M. cinereus were transported from offshore areas in the East China Sea to Jeju Island and the Korea Strait (KS) by the Kuroshio and Tsushima Warm Current.

Zircon U–Th–Pb dating using LA-ICP-MS: Simultaneous U–Pb and U–Th dating on the 0.1 Ma Toya Tephra, Japan

Simultaneous U–Pb and U–Th zircon dating using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was performed on the ~0.1Ma Toya Tephra, Hokkaido, Japan. The method employs the concurrent measurement of 206Pb, 230Th, and 238U signals, which enables the determination of 238U–206Pb (U–Pb) and 238U–230Th (U–Th) ages simultaneously. The U–Pb ages revealed that the Toya Tephra contains zircons with ages that cluster at ~0.1Ma (0.11±0.01Ma: error shown as 95% confidence level) and xenocrysts with ages >2Ma. Excluding zircons >2Ma, the U–Th method also gave an isochron age of ~0.1Ma (108±19ka or 0.11±0.02Ma; error shown as 2σ). Therefore, both U–Pb and U–Th methods result in similar ages of ~0.1Ma for the Toya Tephra, in agreement with the quartz TL age (104±30 to 118±30ka) of Ganzawa and Ike (2011). It was revealed that the simultaneous U–Pb and U–Th zircon dating technique using LA-ICP-MS is easy to apply and is useful for Quaternary tephras in that it can give age information on the tephra itself and xenocrystic zircons in a quick and cost-effective manner. The double dating technique employed here has the merit that zircons yielding Quaternary U–Pb ages can be immediately cross-checked by the U–Th method. It was also revealed that the Toya Tephra magma crystallized zircons and experienced eruptions instantaneously at ~0.1Ma, which is an important implication to decipher magmatic and eruptive processes for caldera-forming large volcanic systems.

How do longitudinal dunes respond to climate forcing? Insights from 25 years of luminescence dating of the Australian desert dunefields

This paper presents a meta-analysis of 689 luminescence age estimates of Australian desert sand dunes. This analysis had two aims: to examine the hypothesis that Quaternary climate changes have forced dune accumulation, and to understand longitudinal dune behaviour from the age-architecture of sand dunes for which stratigraphic information is often absent or poorly known. A novel approach to the analysis of probability density curves of dune age frequency shows that in the Mallee dunefield of southeastern Australia only the period leading up to and including the last glacial maximum (LGM) (18–34 ka) experienced marked dune growth which cannot be explained by random stochastic activity. During the LGM, most, but not all, Mallee longitudinal dunes were accumulating more rapidly than before and after. In the Strzelecki dunefield source-bordering (SBD) longitudinal dune TL (n = 61) and OSL (n = 40) ages are more frequent at the Pleistocene–Holocene transition but nearby non-SBD longitudinal dunes (n = 21 ages) were only active above background levels during the LGM. However, the Strzelecki dune age data set suffers from being drawn from a small number of individual dunes (10 SBD dated using TL; 12 SBD dated by OSL; 7 non-SBD dated by OSL) with a marked bias away from surficial (young) and basal (old) depths. Even during the LGM, many dunes do not record active growth and the dunefield was most likely a mosaic of stable dune surfaces and bare mobile patches, supported by the scant pollen data from the arid zone. Hyper-aridity has not been experienced in these dunefields. These vegetated dunes exhibit conservative behaviour with limited response to the range of climate forcing experienced in the late Pleistocene. A more complete understanding of dunefield response to Quaternary climates would require an intensive and structured dating program to overcome the ‘noise’ from stochastic processes leading to small-scale activity in these dunes and the simultaneous removal of parts of the sedimentary record.

Late Pleistocene coastal loess deposits of the central west coast of North America: Terrestrial facies indicators for marine low-stand intervals

Abstract Coastal loess deposits measured in sea cliffs, bay cliffs, road cuts and boreholes (62 sites) are compiled for the states of Washington, Oregon, and California in the central west coast of North America (1700 km in length). The loess-enriched deposits are recognized by (1) substantial abundances of silt (30–90% by weight) and (2) depositional settings in uplifted marine terraces or dune fields that are situated well above alluvial floodplains at the coast. Total loess thickness above the MIS5a marine terrace, or 80 ± 20 ka basal TL age, ranges from 0.1 to 8.0 m in 46 dated sites. Loess deposits reach maximum thickness (5–8 m) in the vicinities of glacial outwash plains in the highest latitudes. Loess thickness in the middle and lower latitudes increases with proximity to 1) large river mouths (>3 × 106 mt yr−1 modern suspended sediment discharge) and 2) broad shelf widths (>10 km distance from 0 to −100 m depth). Coastal loess deposits dated by TL or radiocarbon (37 samples) range from ∼250 to 11 ka in age, but generally fall into the MIS4-2 marine low-stand intervals (32 dates between 77–15 ka). The coastal loess facies represent marine low-stand intervals in coastal Quaternary sequences from the central west coast of North America.

ESR dating of Pleistocene mammals and marine shells from the coastal plain of Rio Grande do Sul state, southern Brazil

The Coastal Plain of Rio Grande do Sul state (CPRS), in southern Brazil, encompasses four barrier-lagoon depositional systems formed by marine highstands during the Quaternary, but the ages of the Pleistocene systems older than ∼125 ka are not precisely known due to the lack of numerical dates. In order to refine the chronology of these deposits, several fossils of terrestrial mammals collected in the fluvial facies of the Lagoon System III and fossil shells from the marine facies of the Barrier System II, exposed in the southern sector of the CPRS, were subject to dating by electron spin resonance (ESR). The ages of the mammalian remains range from 90 ± 10 to 43 ± 3 ka, thus representing the last glacial cycle (MIS 4 and 3). The mean EU age of the shells is 224 ± 24.6 ka, but this value is considered younger than the ‘real’ age because of excessive Uranium uptake observed among the younger shells. An estimated mean age of some 235–238 ka would agree with other ESR and TL ages obtained for fossils and sediments collected from beds overlying the shells, and would be consistent with the sea-level highstand at the early MIS 7 (substage 7e). The presence of bivalves and foraminifers that indicate ocean temperatures higher than at present seems to corroborate this estimate, given that MIS 7e was characterized by hypsithermal conditions.

Combined ESR/U-series chronology of Acheulian hominid-bearing layers at Trinchera Galería site, Atapuerca, Spain

The Sierra de Atapuerca, northern Spain, is known from many prehistoric and palaeontological sites documenting human prehistory in Europe. Three major sites, Gran Dolina, Galería and Sima del Elefante, range in age from the oldest hominin of Western Europe dated to 1.1 to 1.3 Ma (millions of years ago) at Sima del Elefante to c.a. 0.2 Ma on the top of the Galería archaeological sequence. Recently, a chronology based on luminescence methods (Thermoluminescence [TL] and Infrared Stimulated Luminescence [IRSL]) applied to cave sediments was published for the Gran Dolina and Galería sites. The authors proposed for Galería an age of 450 ka (thousands of years ago) for the units lower GIII and GII, suggesting that the human occupation there is younger than the hominid remains of Sima de los Huesos (>530 ka) around 1 km away.In this paper, we present new results obtained by combined Electron Spin Resonance/Uranium-series (ESR/U-series) dating on 20 herbivorous teeth from different levels at the Galería site. They are in agreement with the TL results for the upper part of the stratigraphic sequence (GIV and GIIIb), in the range of between 200 and 250 ka. But for the GIIIa to GIIb levels, the TL ages become abruptly older by 200 ka while ESR ages remain relatively constant. Finally, the TL and ESR data agree in the lowest part of the section (GIIa); both fall in the range of around 350–450 ka. Our results suggest a different interpretation for the GII, GIII and GIV units of Galería and the upper part of Gran Dolina (TD10 and TD11) than obtained by TL. The ESR/U-series results are supported by a Bayesian analysis, which allows a better integration between stratigraphic information and radiometric data.