ALBERT

Description: Deposits in coastal lakes in northernmost Norway reveal that the Storegga tsunami propagated well into the Barents Sea ca. 8100–8200 years ago. A tsunami deposit – found in cores from five coastal lakes located near the North Cape in Finnmark – rests on an erosional unconformity and consists of graded sand layers and re-deposited organic remains. Rip-up clasts of lake mud, peat and soil suggest strong erosion of the lake floor and neighbouring land. Inundation reached at least 500 m inland and minimum vertical run-up has been reconstructed to 3–4 m. In this part of the Arctic coastal lakes are usually covered by 〉1 m of solid lake ice in winter. The significant erosion and deposition of rip-up clasts indicate that the lakes were ice free and that the ground was probably not frozen. We suggest that the Storegga slide and ensuing tsunami happened sometime in the summer season, between April and October. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The complex cyclical nature of Pleistocene climate, driven by the evolving orbital configuration of the Earth, is well known but not well understood. A major climatic transition took place at the Mid-Brunhes Event (MBE), ca. 430 ka ago after which the amplitude of the ca.100 ka climate oscillations increased, with substantially warmer interglacials, including periods warmer than present. Recent modelling has indicated that while the timing of these warmer-than-present transient (WPT) events is consistent with southern warming due to a deglaciation-forced slowdown of the Atlantic Meridional Overturning Circulation, the magnitude of warming requires a local amplification, for which a candidate is the feedback of significant West Antarctic Ice Sheet (WAIS) retreat. We here extend this argument, based on the absence of WPTs in the early ice core record (450–800 ka ago), to hypothesize that the MBE could be a manifestation of decreased WAIS stability, triggered by ongoing subglacial erosion. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We reconstructed the long-term spruce budworm (SBW) ( Choristoneura fumiferana Clem.) outbreak dynamics in the boreal forest of Quebec (Canada) using a dendrochronological approach with subfossil trees. Although the majority of the excavated wood belonging to the genus Picea could potentially reveal the past activity of spruce budworms in the tree rings, very few were cross-dated due to a lack of marker rings. All cross-dated trees were found within a particular zone of the peat bogs and the floating chronology was radiocarbon dated to ca. 5.1 cal ka BP. The results presented in this study suggest that the dynamics of SBW outbreaks in the studied area fluctuated during the last millennia and that severe outbreaks as observed during the 20th century seldom occurred in that part of the boreal forest since the end of the last glaciation. These results are in agreement with observations from other parts of eastern North America. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The glacial isostatic adjustment (GIA) of the British Isles is of interest due to the constraints that can be provided on key model parameters such as the global meltwater signal, local ice sheet history and viscoelastic earth structure. A number of recent studies have modelled relative sea-level (RSL) data from this region to constrain model parameters. As indicated in these studies, the sensitivity of these data to both local and global parameters results in a highly non-unique problem. This study aims to address this inherent non-uniqueness by combining a previously published British–Irish ice model that is based on the most recent geomorphological data with a new global ice sheet model that provides an accurate prediction of eustatic sea-level change. In addition, constraints from Global Positioning System (GPS) measurements of present-day vertical land motion are considered alongside the entirety of RSL data from both Great Britain and Ireland. A model solution is found that provides a high-quality fit to both the RSL data and the GPS data. Within the range of earth viscosity values considered, the optimal data model fits were achieved with a relatively thin lithosphere (71 km), upper mantle viscosities in the range 4–6 × 10 20 Pa s and lower mantle viscosities ≥ 3 × 10 22 Pa s. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The chronostratigraphy of a long, onshore Early–Middle Pleistocene marine sedimentary sequence on the south-east part of Zakynthos island, Greece, is presented. Correlation of the succession with the isotope record of Ocean Drilling Program Site 963 reveals the combined influence of tectonics and eustacy in this area. The sequence is divided into three formations by two main unconformities that apparently relate to sea-level lowstands associated with two major northern hemisphere glaciations, those of marine isotope stages (MIS) 22 and 12. The Zakynthos sequence in many ways is comparable with the Italian Valle di Manche section. Magnetostratigraphic and rock magnetic analyses, supported by biostratigraphy, document the position of the Matuyama/Brunhes Chron boundary (0.77 Ma), the top and base of the Jaramillo Subchron (0.99–1.07 Ma), the Cobb Mountain Subchron (1.173–1.185 Ma) and the top of the Olduvai Subchron (1.78 Ma). The underlying strata are constrained exclusively by detailed nannofossil biostratigraphy extending at least to the lowermost Pleistocene at around 2.54 Ma and therefore certainly incorporating the base of the Olduvai Subchron (1.95 Ma) and possibly the Gauss/Matuyama Chron boundary (2.58 Ma). In addition, a remarkable increase in sedimentation rate (from 3.2 and 28 cm ka −1 to 167 cm ka −1 ) and hence resolution above the Matuyama/Brunhes boundary (Middle Pleistocene) reveals one short-lived magnetic excursion, possibly 17a (0.66 Ma), within the normal polarity Brunhes Chron. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Since the Mid Pleistocene Revolution, which occurred about one million years ago, global temperatures have fluctuated with a quasi-periodicity of ca. 100 ka. The pattern of past change in the extent of woodlands, and therefore by inference vegetation carbon storage, has been demonstrated to have a strong positive link with this global temperature change at high and mid latitudes. However, understanding of climate systems and ecosystem function indicates that the pattern of woodland change at low latitudes may follow a fundamentally different pattern. We present output from the intermediate complexity model GENIE-1, comprising a single transient simulation over the last 800 ka and a 174-member ensemble of 130 ka transient simulations over the last glacial cycle. These simulations suggest that while vegetation carbon storage in mid–high northern latitudes robustly follows the characteristic ca. 100 ka cycle, this signal is not a robust feature of tropical vegetation, which is subject to stronger direct forcing by the precessional (21 ka) orbital cycle (albeit with a highly uncertain response). We conclude that the correlation of palaeoenvironmental records from low latitudes with global temperature change must be done with caution. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The number and types of late Quaternary records of tropical cyclones (TCs) and temperate storms have been increasing globally over the past 10 years. There are now numerous such records for the Atlantic Ocean (USA) and Gulf of Mexico and Caribbean Sea, South Pacific Ocean, and a fewer number from the northwest Pacific and Indian Ocean regions. The most obvious characteristic of these records is that many reveal extended alternating periods of greater and lesser TC activity over the past 6000 years. The length of these phases of relative inactivity and greater activity depends on the chronological resolution of the record, with the coarser-resolution ones displaying multi-century to millennial-scale episodes and the high-resolution records displaying decadal to centennial-scale oscillations. In several instances the likely causes of these alternating periods of TC behaviour have been attributed to different phases of climate when El Niños and La Niñas dominated or to longer-term variations in sea surface temperatures and possibly solar forcing. The picture emerging from these records is that TC behaviour is not entirely stochastic over the long term and that any simulations of long-term TC behaviour need to account for these climatic influences. Incorporation of these observations, and the many more needed, is important for understanding the future behaviour of TCs. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A revised chronological framework for the deglaciation of the Lake Michigan lobe of the south-central Laurentide Ice Sheet is presented based on radiocarbon ages of plant macrofossils archived in the sediments of low-relief ice-walled lakes. We analyze the precision and accuracy of 15 AMS 14 C ages of plant macrofossils obtained from a single ice-walled lake deposit. The semi-circular basin is about 0.72 km wide and formed of a 4- to 16-m-thick succession of loess and lacustrine sediment inset into till. The assayed material was leaves, buds and stems of Salix herbacea (snowbed willow). The pooled mean of three ages from the basal lag facies was 18 270 ± 50 14 C a BP (21 810 cal. a BP), an age that approximates the switch from active ice to stagnating conditions. The pooled mean of four ages for the youngest fossil-bearing horizon was 17 770 ± 40 14 C a BP (21 180 cal. a BP). Material yielding the oldest and youngest ages may be obtained from sediment cores located at any place within the landform. Based on the estimated settling times of overlying barren, rhythmically bedded sand and silt, the lacustrine environment persisted for about 50 more years. At a 67% confidence level, the dated part of the ice-walled lake succession persisted for between 210 and 860 cal. a (modal value: 610 cal. a). The deglacial age of five moraines or morainal complexes formed by the fluctuating margin of the Lake Michigan lobe have been assessed using this method. There is no overlap of time intervals documenting when ice-walled lakes persisted on these landforms. The rapid readvances of the lobe during deglaciation after the last glacial maximum probably occurred at some point between the periods of ice-walled lake sedimentation. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The palaeontological site of Venta Micena (Orce, Andalusia, Spain) lies in the eastern sector of the Guadix–Baza basin, one of the best documented areas in Europe for Plio-Pleistocene biostratigraphy. The combination of biochronological and palaeomagnetic results, combined with the radiometric data obtained for Atapuerca Sima del Elefante, indicated that the Venta Micena stratum was formed between the Jaramillo and Olduvai palaeomagnetic events, most likely between 1.22 and 1.77 Ma. Five fossil teeth from two outcrops (sites A and B) were selected to assess the potential of combined uranium series–electron spin resonance (US-ESR) dating of Early Pleistocene sites. Although the US-ESR results of the first outcrop showed a large scatter between the three teeth, the mean age of 1.37 ± 0.24 Ma can be considered a reasonable age estimate for Venta Micena. The mean ESR age of 0.62 ± 0.03 Ma obtained for site B seems to be a severe underestimation when compared with the independent age control. This underestimation is attributed to a relative recent U-mobilization event that led to some U-leaching. The results show that any ESR age calculations of old samples are extremely sensitive to variations in the measured 230 Th/ 234 U ratios in dental tissues. Although the results demonstrate that ESR can in principle be applied to Early Pleistocene sites, they also reveal the complexity of dating such old teeth. It is necessary to continue research in several directions, such as study of the behaviour of ESR signals in old teeth and understanding recent U-mobilization processes, to improve the reliability of the combined US-ESR dating method applied to Early Pleistocene times, a period for which the number of available numerical dating techniques is very limited. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A chronostratigraphy based on luminescence data was established at a key loess profile (Duttendorf) in the northern alpine foreland of Austria. The data help to constrain the timing and duration of the Last Glacial Maximum (LGM) in the area of one of the largest east Alpine piedmont glaciers, the Salzach palaeoglacier. Climate deterioration and maximum advance of this glacier were coeval with the beginning of the main loess accumulation phase in the glacier forefield at ∼29–30 ka. A late LGM-outwash gravel layer deposited on top of the loess profile marks the end of the LGM glacier activity at ∼20 ka. The geomorphological setting around the loess profile provides evidence of a major glacier oscillation during the course of the LGM, a phenomenon qualitatively known from other alpine palaeoglaciers but never interpreted in terms of palaeoclimate. A LGM glacier oscillation similar to that of the Salzach palaeoglacier was reported recently from the south Alpine Tagliamento palaeoglacier, suggesting a common forcing. The onset of loess deposition at Duttendorf and the tentatively contemporal advance of the Salzach palaeoglacier reflect, as do other data, the drastic cooling in Europe as a result of Heinrich event 3. The first glacier maximum is not well constrained in the study area but a correlation with the better dated Tagliamento amphitheatre suggests a possible response to Heinrich 2. The second re-advance occurred synchronously (within dating uncertainties) in both palaeoglaciers forefields (at ∼21 ka) but the forcing mechanism remains unknown. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Annually resolved June–July–August (JJA) temperatures from ca. 570 BC to AD 120 (±100 a; approximately 690 varve years) were quantified from biogenic silica and chironomids (Type II regression; Standard Major Axis calibration-in-time) preserved in the varved sediments of Lake Silvaplana, Switzerland. Using 30 a (climatology) moving averages and detrended standard deviations (mean–variability change, MVC), moving linear trends, change points and wavelets, reconstructed temperatures were partitioned into a warmer (+0.3°C; ca. 570–351 BC), cooler (−0.2°C; ca. 350–16 BC) and moderate period (+0.1°C; ca. 15 BC to AD 120) relative to the reconstruction average (10.9°C; reference AD 1950–2000 = 9.8°C). Warm and variable JJA temperatures at the Late Iron Age–Roman Period transition (approximately 50 BC to AD 100 in this region) and a cold anomaly around 470 BC (Early–Late Iron Age) were inferred. Inter-annual and decadal temperature variability was greater from ca. 570 BC to AD 120 than the last millennium, whereas multi-decadal and lower-frequency temperature variability were comparable, as evident in wavelet plots. Using MVC plots of reconstructed JJA temperatures from ca. 570 BC to AD 120, we verified current trends and European climate model outputs for the 21st century, which suggest increased inter-annual summer temperature variability and extremes in a generally warmer climate (heteroscedasticity; hotspot of variability). We compared these results to MVC plots of instrumental and reconstructed temperatures (from the same sediment core and proxies but a different study) from AD 1177 to AD 2000. Our reconstructed JJA temperatures from ca. 570 BC to AD 120 showed that inter-annual JJA temperature variability increased rapidly above a threshold of ∼10°C mean JJA temperature. This increase accelerated with continued warming up to 〉11.5°C. We suggest that the Roman Period serves with respect to inter-annual variability as an analogue for warmer 21st-century JJA temperatures in the Alps. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Stable isotopes and element compositions of the fine-grained matrix were measured for IODP Expedition 307 Hole U1317E drilled from the summit of Challenger Mound in Porcupine Seabight, northeast Atlantic, to explore the palaeoceanographic and palaeoclimatic background to development of the deep-water coral mound. The 155 m long mound section was divided into two units by an unconformity at 23.6 mbsf: Unit M1 (2.6–1.7 Ma) and Unit M2 (1.0–0.5 Ma). Results from 519 specimens show a difference in δ 13 C value between Unit M1 (−0.6‰ to −5.0‰) and Unit M2 (−1.0‰ to 1.0‰), but such a distinct difference was not seen in δ 18 O values (1.0‰–2.5‰), CaCO 3 content (40–60 wt%), Sr/Ca ratio (2.0–8.0 mmol mol −1 ), and Mg/Ca ratio (10.0–20.0 mmol mol −1 ) through the mound. Positive δ 18 O and negative δ 13 C shifts at the mound base are consistent with the oceanographic changes in the northeast Atlantic at the beginning of the Quaternary. The positive δ 13 C regression in Unit M2 suggests a linkage to the mid Pleistocene intensified glaciation in the Northern Hemisphere. Warm Mediterranean Upper Core Water of Mediterranean Outflow Water, Eastern North Atlantic Water and cold Labrador Sea Water of North Atlantic Deep Water are key oceanographic features that cause spikes and shifts in stable isotope and element composition. However, the stable isotope values of the sediment matrix could not primarily record the glacial–interglacial eustatic/temperature change, but indirectly indicate current regimes of the intermediate oceanic layer where the coral mound grew. Similarly, elemental ratios and CaCO 3 content may not represent the productivity and temperature of surface sea water, respectively, but superpose the fractions from both surface and bottom water. It is concluded that palaeoceanographic change coupled to the Pleistocene glacial/interglacial cycles is a key control on the geochemical stratigraphy of the matrix sediments of the carbonate mound developed in Porcupine Seabight. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The European Alps are very sensitive and vulnerable to climate change. Recent improvements in Alpine glacier length records and climate reconstructions from annually laminated sediments of Alpine Lake Silvaplana give the opportunity to investigate the relationship between these two data sets of Alpine climate. Two different time frames are considered: the last 500–1000 years as well as the last 7400 years. First, we found good agreement between the two different climate archives during the past millennium: mass accumulation rates and biogenic silica concentration are largely in phase with the glacier length changes of Mer de Glace and Unterer Grindelwaldgletscher, and with the records of glacier length of Grosser Aletschgletscher and Gornergletscher. Secondly, the records are compared with temporally highly resolved data of solar activity. The Sun has had a major impact on the Alpine climate variations in the long term, i.e. several centuries to millennia. Solar activity varies with the Hallstatt periodicity of about 2000 years. Hallstatt minima are identified around 500, 2500 and 5000 a. Around these times grand solar minima (such as the Maunder Minimum) occurred in clusters coinciding with colder Alpine climate expressed by glacier advances. During the Hallstatt maxima around 0, 2000 and 4500 a, the Alpine glaciers generally retreated, indicating a warmer climate. This is supported by archaeological findings at Schnidejoch, a transalpine pass in Switzerland that was only accessible when glaciers had retreated. On shorter timescales, however, the influence of the Sun cannot be as easily detected in Alpine climate change, indicating that in addition to solar forcing, volcanic influence and internal climate variations have played an important role. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We present a new regional calibration of the 10 Be production rate from two well-dated surfaces in southern Norway: a rock avalanche with 14 C-dated wood and a precisely dated Younger Dryas moraine. Calculated 10 Be production rates are 4.26 ± 0.13 and 4.65 ± 0.14 at g −1 a −1 for the Lal/Stone and Lifton scaling models, respectively. Our regional production rate for southern Norway is 5% lower than the canonical global 10 Be production rate with lower uncertainties. Our 10 Be production rate agrees with regional 10 Be production rates from north-eastern North America and New Zealand. The 10 Be production rate estimate presented here can be used to improve the precision and accuracy of exposure-dated ice-marginal features, as well as other surfaces, in northern Europe. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The development of the Lancaster Sound Trough Mouth Fan (TMF) and glacial history in Arctic Canada were studied using a high-resolution seismic profile across the entire fan and two piston cores. Stacked tills separated by erosion surfaces on the shelf pass seaward through till deltas into thick transparent glacigenic debris flow (GDF) deposits on the slope, separated by thin, well-stratified glaciomarine layers. An age model was built by ties to the Ocean Drilling Program Site 645. The deepest GDF on the seismic profile was indicative of the onset of shelf-crossing glaciation in the Early Pleistocene. The transition of the growth of Lancaster Sound TMF from an aggradational sequence (unit M) to an aggradational–progradational sequence (unit F) occurred at the Middle Pleistocene transition in glacial cyclicity. In the most recent glacial cycle, GDF sheets were deposited during Heinrich events 4 and 2 according to the correlation of the main detrital carbonate beds in two piston cores. The outmost till wedge reflects the maximum advance of the grounding glacier, far seaward of previously proposed Last Glacial Maximum ice extent. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Montaña Negra is a 121 m cinder cone in the Bandas del Sur region of southern Tenerife. Formed in the Middle Pleistocene, it comprises alternating phonolitic pumice deposits and scoria layers; the latter are extremely fossiliferous with good taphonomical fidelity. 40 Ar/ 39 Ar age determination provides new dates of 302 ± 7.6 ka and 299.9 ± 11.4 ka for the Lower and Upper Aldea Blanca pumice fall deposits, respectively. This chronological constraint allows comparison of the palaeo-habitat with the global climate at the time of pyroclastic activity. Abundant terrestrial gastropod species and rare disarticulated Coleoptera fragments are to be found. The occurrence of the endemic semi-slug genus Plutonia (Family Vitrinidae) is significant in indicating a woodland habitat in the region during the Middle Pleistocene. We suggest that this may have been forest, possibly dominated by laurel, which is in stark contrast to the present-day semi-desert. Copyright © 2011 John Wiley & Sons, Ltd.

Description: In this study we have obtained 17 cosmogenic exposure ages from three well-developed moraine systems – Halland Coastal Moraines (HCM), Göteborg Moraine (GM) and Levene Moraine (LM) – which were formed during the last deglaciation in southwest Sweden by the Scandinavian Ice Sheet (SIS). The inferred ages of the inner HCM, GM and LM are 16.7 ± 1.6, 16.1 ± 1.4 and 13.6 ± 1.4 ka, respectively, which is slightly older than previous estimates of the deglaciation based on the minimum limiting radiocarbon ages and pollen stratigraphy. During this short interval from 16.7 ± 1.6 to 13.6 ± 1.4 ka a large part (100–125 km) of the marine-based sector of the SIS in southwest Sweden was deglaciated, giving an average ice margin retreat between 20 to 50 m a −1 . The inception of the deglaciation pre-dated the Bølling/Allerød warming, the rapid sea level rise at 14.6 cal. ka BP and the first inflow of warm Atlantic waters into Skagerrak. We suggest that ice retreat in southwest Sweden is mainly a dynamical response governed by the disintegration of the Norwegian Channel Ice Stream and not primarily driven by climatic changes. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Early Pleistocene vegetation in upland southeastern Australia included diverse rainforests and sclerophyll forests, which alternated on precessional timescales. The nature and timing of transitions between these biomes, and the role of fire in maintaining or driving transitions between them, are uncertain. Here we present a high-resolution pollen record from Stony Creek Basin, a small Early Pleistocene palaeolake in southeastern Australia. The pollen record documents a pattern of vegetation change, over ca. 10 ka at ca. 1590–1600 ka, between sclerophyll forests, dominated by Eucalyptus , Callitris (Cupressaceae) or Casuarinaceae, and rainforests dominated by either angiosperms or conifers of the family Podocarpaceae. Transitions between these biomes typically occurred within ca. 1–2 ka. The associated charcoal record suggests that greatest biomass combustion occurred when local vegetation was dominated by Eucalyptus , and the least biomass combustion occurred when local vegetation was dominated by Podocarpaceae. However, local fires burnt in both sclerophyll and angiosperm-dominated rainforest vegetation, at least once every several centuries. Fire was very rare (less than about one fire per millennium) only when the local vegetation was rainforest dominated by Podocarpaceae. This suggests that fire was an irregular presence in both sclerophyll- and angiosperm-dominated rainforest biomes during the late Neogene, though was largely absent in Podocarpaceae-dominated rainforests. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The inflow of Atlantic Water to the Nordic seas from mid–late Younger Dryas to earliest Holocene (12 450–10 000 a BP) is reconstructed on the basis of a high-resolution core (LINK14) from 346 m water depth on the east Faroe shelf. We have analysed the distribution of planktic and benthic foraminifera, stable isotopes and ice-rafted debris (IRD), and calculated absolute temperatures and salinities by transfer functions. During the investigated time period there was almost continuous inflow of Atlantic Water to the Nordic seas. Deposition of IRD during the mid–late Younger Dryas and Pre-Boreal coolings indicates the presence of melting icebergs and that summer sea surface temperatures were low. The east–west temperature gradient across the Faroe–Shetland Channel was much steeper than today. The cold conditions around the Faroe Islands are attributed to stronger East Greenland and East Icelandic currents than at present. The near-continuous inflow of Atlantic Water is consistent with published evidence suggesting that deep convection took place in the Nordic seas, although the convection sites probably had shifted to a more easterly position than at present. Around the time of deposition of the Saksunarvatn Tephra c. 10 350 a BP, sea surface temperatures increased to the present level. Copyright © 2011 John Wiley & Sons, Ltd.

Description: In general, mires develop by autogenic succession from more groundwater-fed to more rainwater-fed. This study from a calcareous mire in the West Carpathians (Slovakia) describes a similar development in the Early Holocene, followed by a reverse development in the Middle and Late Holocene. Pollen, macrofossil and testate amoeba analyses show that the site started as a minerotrophic open fen woodland. After 10 700 cal a BP autogenic succession led to the accumulation of at least 1 m of Sphagnum fuscum peat. Around 9000 cal a BP, as climate could no longer sustain a stable water regime, the bog desiccated and a fire broke out. The fire removed part of the peat layer and as a consequence relative water levels rose, leading to the establishment of a wet minerotrophic swamp carr with Thelypteris palustris , Equisetum sp. and Alnus sp. with extremely slow peat accumulation. After 600 cal a BP, rapid peat accumulation with calcareous tufa formation resumed as a result of anthropogenic deforestation and hydrological changes in the catchment and resulting increased groundwater discharge. At present the mire still hosts a wealth of relict and endangered plant and animal species typical of calcareous fens and fen meadows. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Relict fluvial and lacustrine deposits in the interior of Oman near Saiwan consist of waterlain breccias with pebble imbrications and current ripples, covered by algal laminites containing calcified reeds and charcoal pieces. Geomorphological evidence suggests that the palaeolake covered a maximum surface of 1400 km 2 and had a maximum depth of about 25 m. Optically stimulated luminescence (OSL) and thermally transferred OSL dating indicate that this palaeolake existed sometime between 132 and 104 ka. The rich archaeological evidence in the area suggests substantial human occupation, possibly at the time when Palaeolake Saiwan existed. Interestingly, the lithic traditions of the archaeological material show no clear relation to coeval findings from neighbouring areas, putting a question mark on the origin of the culture found at Saiwan. This finding raises questions concerning the origin of the population inhabiting Saiwan, as the site lies along one possible route for the dispersal of anatomically modern humans out-of-Africa. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The Arctic is more vulnerable to climate change than are mid latitudes. Therefore, palaeolimnological studies from the High Arctic are important in providing insights into the dynamics of the climate system. Here we present a multi-proxy study from one of the world's northernmost lakes: Bliss Lake, Peary Land, Greenland. The early Holocene (10 850–10 480 cal. a BP) is characterized by increased erosion and gradually more marine conditions. Full marine conditions developed from 10 480 cal. a BP until the lake was isolated at 7220 cal. a BP. From its marine isolation at 7220 cal. a BP Bliss Lake becomes a lacustrine environment. Evidence from geochemical proxies (δ 13 C and total organic carbon) suggests that warmer conditions prevailed between 7220 and 6500 cal. a BP, corresponding to the Holocene thermal maximum, and from 3300 until 910 cal. a BP. From 850 to 500 cal. a BP colder climate conditions persisted. The transition from warmer to colder climate conditions taking place around 850 cal. a BP may be associated with the transition from the Medieval Warm Period to the Little Ice Age. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Extreme Late Quaternary climatic events, sometimes of considerable continental extent, are being proposed as major contributors to ancestral human behaviour, particularly migration, in Africa. Most recently, a catastrophic drought in the Afro-Asian monsoon region has been proposed for 16 000–17 000 years ago, driven by global impacts of the Heinrich event 1 (H1), with potentially significant consequences for Palaeolithic cultures. We provide a new analysis of the assertion and find, on examination of a wide set of palaeoenvironmental records, that the scale and extent of the proposed drought is not supported. While some parts of the African tropics, close to the equator, do appear dry at this time, data for the tropics as a whole suggest markedly variable terrestrial conditions, with some environmental systems experiencing very positive hydrological excursions during H1. We contend that in the quest for evidence of climate drivers of ancestral human behaviour, the variability associated with spatially and temporally complex climatic conditions is a significant factor in itself. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Two gravity sediment cores (GH99-1239 and GH99-1246) obtained from the north-eastern Japan Basin in the East Sea/Japan Sea were analyzed for the orbital- and millennial-scale paleoceanographic changes. Chronostratigraphically, core GH99-1239 represents a continuous sedimentary record since 32 ka, based on correlation of distinct lithological markers (i.e. dark layer or TL layer) with those in core GH98-1232 collected nearby. For core GH99-1246, the age model is constructed through correlation of lightness ( L *) values and tephra (Aso-4 and Toya) layers with those in the well-dated Oki Ridge core (MD01-2407), indicating about 134 ka of sedimentation since the latest Marine Isotope Stage (MIS) 6. New geochemical data from both cores corroborate orbital-scale paleoceanographic variation, such that surface-water productivity, represented by biogenic opal and total organic carbon (TOC) contents, increased during MIS 1 and MIS 5; CaCO 3 contents do not show such distinct glacial–interglacial cycles, but were influenced by dissolution and preservation rather than foraminiferal production. During the glacial periods when sea ice was prevalent, surface-water productivity was low, and bottom-water conditions became anoxic, as indicated by high total sulfur (TS) contents and high Mo concentrations. The geochemical data further document millennial-scale paleoceanographic variability, corresponding to a series of thin TL layers in response to Dansgaard–Oeschger cycles but irrespective of the glacial or interglacial periods. In particular, thin TL layers formed during MIS 3 are characterized by less TOC (about 1%) and TS (about 0.4%) contents and lower Mo (about 5 p.p.m.) concentration, whereas those during MIS 4 and MIS 5 exhibit more TOC (up to 4%) and TS (up to 5%) contents and higher Mo (up to 120 p.p.m.) concentration. Such a discrepancy is attributed to different degree of surface-water productivity and of bottom-water oxygenation, which is closely related to the sea level position and extent of ventilation. Flux of the East China Sea Coastal Water controlled by millennial-scale paleoclimatic events is the most critical factor in deciding the properties of TL layers in the north-eastern Japan Basin. Our results strongly confirm that TL layers in the Japan Basin also validate the unique feature of basin-wide paleoceanographic signals in the East Sea/Japan Sea. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Human activities have an impact on extant biotic communities, and may have had just as important an impact in the past. We assess human impact on limpet assemblages during the Upper Palaeolithic in Asturias (north-west Spain). The intensely exploited genus Patella exhibited a marked size decrease and a change in species assemblage composition, substituting the larger species P. vulgata for the smaller P. depressa . The present Patella assemblages in the upper tidal level exhibit the same pattern as those of the Epipalaeolithic (approx. 12 000 to 6000 years before the present). Although climate change may have contributed to such species replacement, spatial differences between close areas with different densities of Palaeolithic human settlements indicate unequivocal human impact. Present Patella species sampled from the region exhibit genetic signatures of past bottlenecks in mitochondrial DNA, which also indicate recent demographic expansion, suggesting that old impacts have been sufficiently important to leave genetic traces in current populations. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Recent research based primarily on exposure ages of boulders on moraines has suggested that extensive ice masses persisted in fjords and across low ground in north-west Scotland throughout the Lateglacial Interstade (≈ Greenland Interstade 1, ca. 14.7–12.9 ka), and that glacier ice was much more extensive in this area during the Older Dryas chronozone (ca. 14.0 ka) than during the Younger Dryas Stade (ca. 12.9–11.7 ka). We have recalibrated the same exposure age data using locally derived 10 Be production rates. This increases the original mean ages by 6.5–12%, implying moraine deposition between ca. 14.3 and ca. 15.1 ka, and we infer a most probable age of ca. 14.7 ka based on palaeoclimatic considerations. The internal consistency of the ages implies that the dated moraines represent a single readvance of the ice margin (the Wester Ross Readvance). Pollen–stratigraphic evidence from a Lateglacial site at Loch Droma on the present drainage divide demonstrates deglaciation before ca. 14.0 ka, and therefore implies extensive deglaciation of all low ground and fjords in this area during the first half of the interstade (ca. 14.7–14.0 ka). This inference appears consistent with Lateglacial radiocarbon dates for shells recovered from glacimarine sediments and a dated tephra layer. Our revised chronology conflicts with earlier proposals that substantial dynamic ice caps persisted in Scotland between 14 and 13 ka, that large active glaciers probably survived throughout the Lateglacial Interstade and that ice extent was greater during the Older Dryas period than during the Younger Dryas Stade. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Spores of the dung-fungi Sporormiella provide a proxy for assessing past changes in herbivore abundance, and for temporally linking these with shifts in vegetation communities (pollen) and fire frequency (charcoal). Although the proxy is now widely used, potential influences of local environmental conditions are poorly understood. Here we assess the reliability of Sporormiella as a proxy of herbivores by presenting five new spore records from the South Island of New Zealand; a land where the herbivore extinction/introduction chronology is well established, and where extinctions occurred independently of major climate change. We show that Sporormiella spores from relatively dry soils provide a good proxy for herbivore extinctions and introductions. However, spore abundances from saturated soil sites appear to fluctuate in close correlation with changes in local hydrology (represented by wetland herb pollen, testate amoebae and moisture sensitive mosses). Our results suggest Sporormiella records derived from wetlands require cautious interpretation, and that proxies for hydrological conditions should also be considered when interpreting such records. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Pollen-based quantitative estimates of seasonal precipitation from Lake Pergusa and lake-level data from Lake Preola in Sicily (southern Italy) allow three successive periods to be distinguished within the Holocene: an early Holocene period before ca. 9800 cal a BP with rather dry climate conditions in winter and summer, a mid-Holocene period between ca. 9800 and 4500 cal a BP with maximum winter and summer wetness, and a late Holocene period after 4500 cal a BP with declining winter and summer wetness. This evolution observed in the south-central Mediterranean shows strong similarities to that recognized in the eastern Mediterranean. But, it contrasts with that reconstructed in north-central Italy, where the mid-Holocene appears to be characterized by a winter (summer) precipitation maximum (minimum), while the late Holocene coincided with a decrease (increase) in winter (summer) precipitation. Maximum precipitation at ca. 10 000–4500 cal a BP may have resulted from (i) increased local convection in response to a Holocene insolation maximum at 10 000 cal a BP and then (ii) the gradual weakening of the Hadley cell activity, which allowed the winter rainy westerlies to reach the Mediterranean area more frequently. After 4500 cal a BP, changes in precipitation seasonality may reflect non-linear responses to orbitally driven insolation decrease in addition to seasonal and inter-hemispheric changes of insolation. Copyright © 2011 John Wiley & Sons, Ltd.

Description: This paper investigates a detailed well-dated Lateglacial floristic colonisation in the eastern Baltic area, ca. 14 000–9000 cal. a BP, using palynological, macrofossil, loss-on-ignition, and 14 C data. During 14 000–13 400 cal. a BP, primarily treeless pioneer tundra vegetation existed. Tree birch ( Betula sect. Albae ) macro-remains and a high tree pollen accumulation rate indicate the presence of forest-tundra with birch and possibly pine ( Pinus sylvestris L.) trees during 13 400–12 850 cal. a BP. Palaeobotanical data indicate that the colonisation and development of forested areas were very rapid, arising within a period of less than 50 years. Thus far, there are no indications of conifer macrofossils in Estonia to support the presence of coniferous forests in the Lateglacial period. Signs of Greenland Interstadial 1b cooling during 13 100 cal. a BP are distinguishable. Biostratigraphic evidence indicates that the vegetation was again mostly treeless tundra during the final colder episode of the Lateglacial period associated with Greenland Stadial 1, approximately 12 850–11 650 cal. a BP. This was followed by onset of the Holocene vegetation, with the expansion of boreal forests, in response to rapid climatic warming. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The Alps play a pivotal role for glacier and climate reconstructions within Europe. Detailed glacial chronologies provide important insights into mechanisms of glaciation and climate change. We present 26 10 Be exposure dates of glacially transported boulders situated on moraines and ice-moulded bedrock samples at the Belalp cirque and the Great Aletsch valley, Switzerland. Weighted mean ages of ∼10.9, 11.1, 11.0 and 9.6 ka for the Belalp, on up to six individual moraine ridges, constrain these moraines to the Egesen, Kartell and Schams stadials during Lateglacial to early Holocene times. The weighted mean age of ∼12.5 ka for the right-lateral moraine of the Great Aletsch correlates with the Egesen stadial related to the Younger Dryas cooling. These data indicate that during the early Holocene between ∼11.7 and ∼9.2 ka, glaciers in the Swiss Alps seem to have been significantly affected by cold climatic conditions initiated during the Younger Dryas and the Preboreal Oscillation. These conditions resulted in glacier margin oscillations relating to climatic fluctuations during the second phase of the Younger Dryas – and continuing into Boreal times – as supported by correlation of the innermost moraine of the Belalp Cirque to the Schams (early) Holocene stage. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The development of the Gurbantunggut Desert is mainly controlled by the Westerly wind, and at present has little influence from Indian and Southeast Asian monsoons. A combined study using optically stimulated luminescence (OSL) dating, ground-penetrating radar (GPR) surveys and climatic proxies analysis was carried out in the southern part of the desert. The chronology extends back to 18 ka and is constructed based on 16 OSL ages from boreholes in the linear dune body and the inter-dune area. The chronology suggests that sand deposition in the last 18 ka experienced two rapid accumulation phases at 11 and 2.5 ka ago which were also evident from the GPR surveys. These periods relate to increased aridity in the region. Five climate phases are identified from the last 18 ka, based on the OSL chronology and climatic proxy analysis with grain size and magnetic susceptibility measurements. The deglacial period (18.3–10.4 ka) is characterized by climate instability and possible glacial melting events. The Holocene Optimum peaked 8.5 ka and terminated 3.6 ka ago, when the regional climate became arid. OSL samples from the dune body cluster around 2.5 ka, which indicates rapid advance/extension of dune bodies at this time. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We present a Lateglacial and early Holocene chironomid-based July air temperature reconstruction from Foppe (1470 m a.s.l.) in the Swiss Southern Alps. Our analysis suggests that chironomid assemblages have responded to major and minor climatic fluctuations during the past 17 000 years, such as the Oldest Dryas, the Younger Dryas and the Bølling/Allerød events in the Lateglacial and the Preboreal Oscillation at the beginning of the Holocene. Quantitative July air temperature estimates were produced by applying a combined Norwegian and Swiss temperature inference model consisting of 274 lakes to the fossil chironomid assemblages. The Foppe record infers average July air temperatures of ca. 9.9 °C during the Oldest Dryas, 12.2 °C during most of the Bølling/Allerød and 11.1 °C for the Younger Dryas. Mean July air temperatures during the Preboreal were 14 °C. Major temperature changes were observed at the Oldest Dryas/Bølling (+2.7 °C), the Allerød/Younger Dryas (−2 °C) and the Younger Dryas/Holocene transitions (+3.9 °C). The temperature reconstruction also shows centennial-scale coolings of ca. 0.8–1.4 °C, which may be synchronous with the Aegelsee (Greenland Interstadial 1d) and the Preboreal Oscillations. A comparison of our results with other palaeoclimate records suggests noticeable temperature gradients across the Alps during the Lateglacial and early Holocene. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The geochemical characteristics of an approximately 6-m-long sediment core collected from the Jeongokri archaeological site (Hantan River, Korea) were examined to determine the provenance of the sediments and to reconstruct the palaeoenvironment of the study area during the Late Pleistocene (200–127 ka). The core sediments were subdivided into two parts based on grain size: an upper (0–380 cm depth) and lower part (〉380 cm depth). The lower part was deposited primarily by fluvial processes during an interglacial period [marine isotope stage (MIS) 7] with warm and humid conditions. Conversely, the upper part was mainly deposited by aeolian processes during a cold and dry glacial period (MIS 6). Geochemical characteristics, represented by major, trace and rare earth element (REE) compositions, and textures of the Jeongokri core sediments show distinct differences between the upper and lower parts. The mineralogy and major, trace and REE compositions indicate that the influence of felsic source rocks (e.g. granite) was dominant in the lower sediments, which were derived from the Hantan River. In contrast, increased quartz content and the very fine and homogeneous grain size in the upper sediments indicate an aeolian origin. REE ratios and distribution patterns, and geochemical signatures indicate that these sediments were derived predominantly from Chinese loess deposits and partially from local sediments from the Korean Peninsula; the possible source area of the upper sediments is the northern part of the Yellow Sea basin. The Yellow Sea basin, having mixed geochemical signatures between Chinese loess and Korean-derived sediments, was exposed because of low sea levels during MIS 6. The exposed Yellow Sea basin was located in the path of winter-monsoon winds, which may have carried a great deal of airborne sediments from the basin to the Jeongokri area. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A pollen record from a sediment core drilled underneath the Acheulian site of Fontana Ranuccio provides new data on the vegetation characters in central Italy during the late Early Pleistocene, in a forest phase possibly corresponding to a substage of Marine Isotope Stage 21. A number of tree taxa nowadays extinct in Europe ( Cathaya , Tsuga , Taxodium type, Carya and Pterocarya ) are present at Fontana Ranuccio in a temperate phase characterised by dense forest conditions, dominated by Alnus and Pterocarya . The comparison of the Fontana Ranuccio record with other dated sites distributed along the Italian peninsula indicates that the floristic and vegetational characters of the Mid Pleistocene revolution present a rather distinct succession of biostratigraphic events. Compared to other Early Pleistocene pollen records from southern Europe, the Italian Peninsula shows greater floristic similarities with the Eastern Mediterranean regions than with the Iberian Peninsula. Copyright © 2011 John Wiley & Sons, Ltd.

Description: For the reliable assessment of past climate variability, quantitative reconstructions of seasonal temperatures are required. Currently, reconstructions of cold-season temperatures are scarce, because most biological proxies are biased towards the growing season. Here we test the potential of chrysophyte stomatocysts (or simply ‘cysts’; siliceous resting stages of the golden-brown algae) as a proxy for cold-season temperature. Climate reconstructions based on biological proxies are commonly constructed using transfer functions derived from calibration in space. However, the performance of these reconstructions is rarely tested by direct comparison with meteorological data due to limitations of sample resolution or chronological control. We compare a cyst-based near-annual reconstruction of ‘date of spring mixing’ from the varved sediments of Lake Silvaplana (Swiss Alps) spanning AD 1870–2004 with climate variables from the same period measured at the lake shore. The high correlation between cyst-based ‘date of spring mixing’ and cold-season temperature demonstrates the ability of chrysophyte cysts to archive cold-season temperature variability. Lake eutrophication, which was extensive during the last 50 years, had no obvious effect on the cyst-based reconstruction. This study underlines the high potential of chrysophyte cysts as a quantitative proxy for cold-season climate reconstructions. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Last interglacial sediments in unglaciated Alaska and Yukon (eastern Beringia) are commonly identified by palaeoecological indicators and stratigraphic position ∼2–5 m above the regionally prominent Old Crow tephra (124 ± 10 ka). We demonstrate that this approach can yield erroneous age assignments using data from a new exposure at the Palisades, a site in interior Alaska with numerous exposures of last interglacial sediments. Tephrochronology, stratigraphy, plant macrofossils, pollen and fossil insects from a prominent wood-rich organic silt unit are all consistent with a last interglacial age assignment. However, six 14 C dates on plant and insect macrofossils from the organic silt range from non-finite to 4.0 14 C ka BP, indicating that the organic silt instead represents a Holocene deposit with a mixed-age assemblage of organic material. In contrast, wood samples from presumed last interglacial organic-rich sediments elsewhere at the Palisades, in a similar stratigraphic position with respect to Old Crow tephra, yield non-finite 14 C ages. Given that local permafrost thaw since the last interglaciation may facilitate reworking of older sediments into new stratigraphic positions, minimum constraining ages based on 14 C dating or other methods should supplement age assignments for last interglacial sediments in eastern Beringia that are based on palaeoecology and stratigraphic association with Old Crow tephra. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Cosmogenic nuclide surface exposure dating of boulders and erratics provides new constraints for a glacial chronology in the source area of the Urumqi River, Tian Shan, China. 10 Be exposure ages of 15.0 ± 1.3–17.1 ± 1.5 ka from the Upper Wangfeng (UWF) moraines agree well with their previous relative age assignments to marine isotope stage (MIS) 2, but are younger than published AMS 14 C and electron spin resonance (ESR) ages (from 22.8 ± 0.6 to 37.4 ka). This difference may result from variations in techniques, or could reflect the impact of surface erosion and sediment/snow cover on surface exposure dating. 10 Be ages from the Lower Wangfeng (LWF) moraines (18.7 ± 1.8 and 16.2 ± 1.5 ka) are indistinguishable from the UWF exposure ages, but are significantly younger than previously reported thermoluminescence (TL) and ESR ages (37.7 ± 2.6–184.7 ± 18 ka). Either these two groups were formed during the same period (MIS 2) and there are problems with TL and ESR ages, or the moraines were of very different ages and the similar exposure ages result from different degrees of degradation. Erratics on rock steps and a drumlin along 〉8 km of the main glacial valley above the UWF have internally consistent and slightly decreasing 10 Be exposure ages indicating glacier retreat 〉2.5 m a −1 after MIS 2 and before middle or late Holocene glacier re-advances. This retreat rate is similar to rates observed from modern glaciers. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Pollen and macrofossil analyses of a sediment core from Beaver Pond (60° 37′ 14″ N, 154° 19′ W, 579 m a.s.l.) reveal a record of regional and local postglacial vegetation change in south-western Alaska. The chronology is based on five AMS (accelerator mass spectrometry) 14 C ages obtained from terrestrial plant macrofossils. Pollen and macrofossil records suggest that open herb and shrub tundra with e.g. Poaceae, Cyperaceae, Artemisia , Vaccinium and Salix prevailed on the landscape before ca. 14 000 cal a BP. The shift from herb- to shrub-dominated tundra ( Salix , subsequent Betula expansion) possibly reflects climatic warming at the beginning of the Bølling period at ca. 14 700–14 500 and around 13 500 cal a BP. Vegetation ( Betula shrub tundra) remained relatively stable until the early Holocene. Macrofossil influx estimates provide evidence for greater biomass in Betula shrub tundra during the early postglacial period than today. Charcoal accumulation rates suggest tundra fire activity was probably greater from ca. 12 500 to 10 500 cal a BP, similar to results from elsewhere in Alaska. The pollen and macrofossil records of Beaver Pond suggest the prevalence of low shrub tundra (shrub Betula , Betula nana , Vaccinium , Ledum palustre , Ericaceae) and tall shrub tundra ( Alnus viridis ssp. crispa , Salix ) between 10 000 and 4000 cal a BP. This Holocene vegetation type is comparable with that of the modern treeless wet and moist tundra in south-western Alaska. The expansion of Picea glauca occurred ∼4000 cal a BP, much later than that of A. viridis (ssp. crispa ), whereas in central and eastern Alaska Picea glauca expanded prior to or coincident with Alnus ( viridis ). At sites located only 200–400 km north-east of Beaver Pond (Farewell and Wien lakes), Picea glauca and Betula forests expanded 8000–6000 cal a BP. Unfavourable climatic conditions and soil properties may have inhibited the expansion and establishment of Picea across south-west Alaska during the mid and late Holocene. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Previous studies on lipid biomarkers preserved in Chinese stalagmites have indicated that ratios of low-molecular-weight (LMW) to high-molecular-weight (HMW) n -alkanes, n -alkan-2-ones, n -alkanols and n -alkanoic acids can be used as an index of vegetation versus microbial organic matter input to the system and, by extension, a marker of climatic changes, with increases in the proportion of LMW compounds coinciding with colder periods. Here we test whether this hypothesis is equally applicable to a different geographical region (north-west Scotland), by examining a stalagmite record of the past 200 years, and a wider range of lipid markers. We also test the applicability of other lipid proxies in this context, including the use of n -alkane ratios, to interpret vegetation changes, and unsaturated alkanoic acid ratios as climatic indicators. The results show that lipid proxies preserved in stalagmites, and especially those related to vegetation, are potentially extremely useful in palaeoenvironmental research. Of particular value is the use of C 27 /C 31 n -alkane ratios as a proxy for vegetation change, clearly indicating variations between herbaceous and arboreal cover. This proxy has now been successfully applied to samples from diverse environments, and can be considered sufficiently robust to be of use in analysing future stalagmite records. It will be of particular value in areas where reliable pollen records are not available, as is often the case with deeper cave deposits. However, the division between LMW and HMW aliphatic compounds is not a clear-cut case of microbial versus plant activity, with the changes in LMW compounds relating more closely to those in their HMW analogues than in specific bacterial biomarkers. The use of unsaturated alkanoic acid ratios here gives conflicting results, with the observed variation through time depending on the isomer measured. The discrepancies between the findings of this study and previous work are likely to be due to the varying controls on the lipids (original organic matter input, and compound degradation), which in turn will be affected by whether the main climatic limiting factor on the soil is temperature or precipitation. This suggests that lipid proxies preserved in stalagmites must be interpreted with care, particularly in the case of bacterial compounds which may be derived from within the cave or from the soil. However, many of these issues can be resolved by the use of multi-proxy studies. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Variability in the abundance of exotic (non-native) pollen in sediment cores has long been considered as a potential proxy for changing atmospheric circulation, but the difficulty of gaining sufficient total exotic pollen and the incomplete understanding of atmospheric pollen transport patterns has hindered its application. In light of recent advances in the study of pollen transport, we present an exotic pollen record from two fjord sediment cores taken from the west (Placentia Bay, Newfoundland) and east (Narsaq Sund, Greenland) Labrador Sea as a basis for studying variations in regional atmospheric circulation. The two cores cover the last ca. 5500 years and indicate a shift in dominant spring/summer air masses at ca. 2000 (southern Greenland) and 3000 cal a BP (Newfoundland) transporting reduced concentrations of pollen from southerly and south-westerly vegetation zones. This may suggest a shift away from more dominantly zonal atmospheric circulation (a feature of positive North Atlantic Oscillation years) to more frequent meridional circulation. These results support sea ice/sea-surface temperature proxy reconstructions from Newfoundland, investigated as part of the same project, which also suggest increased winter atmospheric circulation during the early part of the time period studied. In this region, more positive North Atlantic Oscillation years, and therefore more zonal atmospheric circulation, are associated with increased atmospheric circulation in both the winter and the summer seasons. Copyright © 2011 John Wiley & Sons, Ltd.

Description: High-resolution charcoal analysis of lake sediment cores was used to reconstruct the fire history from two sites in a mesic hardwood forest of south-eastern Wisconsin located in the Kettle Moraine State Forest. Pollen data from the region indicate that the sites, which lie within 5 km of each other, have had a consistent presence of mesic hardwood forest for the last 6500 years. A pollen record from one of the sites confirmed the regional vegetation history and the charcoal analysis indicated that fire frequency at each site was temporally linked to regional drought. Periods of high fire occurrence occurred in connection with a region-wide drought 4200 years ago and, over the last 2000 years, shorter-scale regional droughts were centred at 1800, 1650, 1100, 1000, 800, 700 and 600 cal a BP. The fire histories indicate that the last 1000 years have had lower fire frequencies than the previous 6500 years and suggest that the mesic hardwood forests may be resilient to increases in fire that may result from future climate change. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Investigation of the sedimentary record of pre-Alpine Lake Mondsee (Upper Austria) focused on the environmental reaction to rapid Lateglacial climatic changes. Results of this study reveal complex proxy responses that are variable in time and influenced by the long-term evolution of the lake and its catchment. A new field sampling approach facilitated continuous and precisely controlled parallel sampling at decadal to sub-annual resolution for µ-XRF element scanning, carbon geochemistry, stable isotope measurements on ostracods, pollen analyses and large-scale thin sections for microfacies analysis. The Holocene chronology is established through microscopic varve counting and supported by accelerator mass spectrometry 14 C dating of terrestrial plant macrofossils, whereas the Lateglacial age model is based on δ 18 O wiggle matching with the Greenland NGRIP record, using the GICC05 chronology. Microfacies analysis enables the detection of subtle sedimentological changes, proving that depositional processes even in rather large lake systems are highly sensitive to climate forcing. Comparing periods of major warming at the onset of the Lateglacial and Holocene and of major cooling at the onset of the Younger Dryas reveals differences in proxy responses, reflecting threshold effects and ecosystem inertia. Temperature increase, vegetation recovery, decrease of detrital flux and intensification of biochemical calcite precipitation at the onset of the Holocene took place with only decadal leads and lags over a ca. 100 a period, whereas the spread of woodlands and the reduction of detrital flux lagged the warming at the onset of the Lateglacial Interstadial by ca. 500–750 a. Cooling at the onset of the Younger Dryas is reflected by the simultaneous reaction of δ 18 O and vegetation, but sedimentological changes (reduction of endogenic calcite content, increase in detrital flux) were delayed by about 150–300 a. Three short-term Lateglacial cold intervals, corresponding to Greenland isotope substages GI-1d, GI-1c2 and GI-1b, also show complex proxy responses that vary in time. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Deglacial sea-level index points defining relative sea-level (RSL) change are critical for testing glacial isostatic adjustment (GIA) model output. Only a few observations are available from North Wales and until recently these provided a poor fit to GIA model output for the British-Irish Ice Sheet. We present results of an integrated offshore geophysical (seismic reflection), coring (drilling rig), sedimentological, micropalaeontological (foraminifera), biostratigraphical (palynology) and geochronological (AMS 14 C) investigation into a sequence of multiple peat/organic sediment horizons interbedded within a thick estuarine–marine sequence of minerogenic clay-silts to silty sands from the NE Menai Strait, North Wales. Ten new sea-level index points and nine new limiting dates from the Devensian Late-glacial and early Holocene are integrated with twelve pre-existing Holocene sea-level index points and one limiting point from North Wales to generate a regional RSL record. This record is similar to the most recent GIA predictions for North Wales RSL change, supporting either greater ice load and later deglaciation than in the GIA predictions generated before 2004, or a modified eustatic function. There is no evidence for a mid-Holocene highstand. Tidally corrected RSL data indicate initial breaching of the Menai Strait between 8.8 and 8.4 ka BP to form a tidal causeway, with final submergence between 5.8 and 4.6 ka BP. Final breaching converted the NE Menai Strait from a flood-dominated estuary into a high energy ebb tidal delta with extensive tidal scouring of pre-existing Late-glacial and Holocene sequences. The study confirms the value of utilising offshore drilling/coring technology to recover sea-level records which relate to intervals when rates of both eustatic and isostatic change were at their greatest, and therefore of most value for constraining GIA models. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The occurrence of the Younger Dryas cold reversal in northern South America midlands and lowlands remains controversial. We present a palaeoecological analysis of a Late Glacial lacustrine section from a midland lake (Lake Chonita, 4.6501 °N, 61.0157 °W, 884 m elevation) located in the Venezuelan Gran Sabana, based on physical and biological proxies. The sediments were mostly barren from ∼15.3 to 12.7 k cal a BP, probably due to poor preservation. A ligneous community with no clear modern analogues was dominant from 12.7 to 11.7 k cal a BP (Younger Dryas chronozone). At present, similar shrublands are situated around 200 m elevation above the lake, suggesting a cooling-driven downward shift in vegetation during that period. The interval from 11.7 to 10.6 k cal a BP is marked by a dramatic replacement of the shrubland by savannas and a conspicuous increase in fire incidence. The intensification of local and regional fires at this interval could have played a role in the vegetation shift. A change to wetter, and probably warmer, conditions is deduced after 11.7 k cal a BP, coinciding with the early Holocene warming. These results support the hypothesis of a mixed origin (climate and fire) of the Gran Sabana savannas, and highlight the climatic instability of the Neotropics during the Late Glacial. Copyright © 2011 John Wiley & Sons, Ltd.

Description: This paper presents a lake-level record for the Holocene at Lake Cerin (Jura Mountains, eastern France). It is based on a range of sedimentological techniques validated in previous studies, with a combination of systematic lithostratigraphic investigations of the infillings accumulated in the lacustrine basin, and sediment analyses of two selected cores. The chronology is based on 10 radiocarbon dates and pollen stratigraphy. On a millennial scale, the Cerin lake-level record shows three distinct successive phases characterised by higher lake-level conditions until ca. 9000 cal. a BP, followed by a maximal lowering at ca. 9000–8500 cal. a BP, and a progressive rise until the present. This rise was punctuated by centennial-scale fluctuations, with major events around 4000, 2800 and after 1500 cal. a BP. Considered on a multimillennial scale, the general pattern of palaeohydrological changes reconstructed at Cerin reflects the impact of orbitally driven summer insolation. This is in agreement with other regional and extra-regional palaeoclimatic records, although every record shows peculiarities in timing and shape depending on the proxy used for reconstruction. In this general context, centennial to multicentennial oscillations appear to have been second-order events in comparison with the major influence of the orbital factor. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Hurricane Ike's storm surge deposited a concentrated shell bed in the form of a series of coalescing washover fans over backshore sand and adjoining marshland in part of southwest Louisiana's Chenier Plain. The shell bed is a tempestite and has distinctive morphological, sedimentological and biogenic characteristics that provide a modern analogue to aid interpretation of older shell bed tempestites in the geological record. The shell bed has a wedge-shaped profile that thickens landward, is about 40 m wide, up to 27 cm thick and extends several hundred metres parallel to the shore. Shells are predominantly disarticulated valves of the common bivalve Mulinia lateralis , probably reworked and transported landward from skeletal remains offshore. The shell bed has an erosional base, is bioclast supported, normally graded and has common mud rip-up clasts. Similarities between the modern shell bed and another concentrated shell deposit, forming part of a sandy beach ridge some 1.5 km inland, suggest that the palaeo shell deposit is also a tempestite recording hurricane washover of a former shoreline 600 a ago. These findings demonstrate that the shell bed deposited by Hurricane Ike is a valuable analogue for palaeotempestological investigations and that hurricanes have likely contributed to the construction of both modern berm ridges and palaeo beach ridges on this coastal plain. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Icelandic tephra layers within deglacial ocean sediment cores from south of Iceland have been detected and their timing with respect to the climate shifts of the last deglaciation constrained. Geochemical analysis of the tephra allowed the likely source volcanic systems to be identified. The previously known Saksunarvatn ash and Vedde ash are recognised and described. Several other major tephra layers are examined: basaltic eruption(s) of Katla at ∼8.4 ka; a basaltic eruption of Katla at ∼12.6 ka; a rhyolitic eruption of Katla at ∼13.6 ka producing tephra similar in appearance and composition to the Vedde ash; a basaltic eruption of Katla at ∼14.0 ka; and two basaltic eruptions of Grímsvötn at ∼14.6 ka and ∼15.0 ka. Abundant rhyolitic ash with a similar appearance and chemistry to the Vedde ash is found throughout the deglacial interval, predating the Vedde ash by up to 3000 years, supporting previous suggestions that there were pre-Vedde ash eruptions of rhyolite that may have contributed to North Atlantic Ash Zone 1. This study expands the tephro-stratigraphic framework of the North Atlantic and provides a marine archive in which the timing of tephra layers (useful as isochrons) can be directly compared to major ocean and climate events of the last deglaciation. Furthermore, by correlating tephra layers and abundance changes in the polar foraminifera, Neogloboquadrina pachyderma (sinistral), to equivalent tephra events and inferred abrupt cooling/warming in Greenland ice-cores, contemporaneous 14 C-dated planktonic foraminifera have been used to estimate changes in the surface radiocarbon reservoir age south of Iceland. Consistent with previous studies, larger surface reservoir ages are calculated during late Heinrich Stadial 1 and the Younger Dryas (∼2000 years and ∼800–1900 years respectively). Copyright © 2011 John Wiley & Sons, Ltd.

Description: Deposits preserved on peaks in the southern Peruvian Andes are evidence for past glacial fluctuations and, therefore, serve as a record of both the timing and magnitude of past climate change. Moraines corresponding to the last major expansion of ice on Nevado Coropuna date to 20-25 ka, during the last glacial maximum. We reconstructed the snowline at Coropuna for this period using a combined geomorphic-numeric approach to provide a first-order estimate of the magnitude of late-Pleistocene climate change. Our reconstructions show that snowline was approximately 550-770 m lower during the last glacial maximum than during the late Holocene maximum, which ended in the 19 th century, and ∼750 m lower than today. While these values are similar to data from nearby Nevado Solimana, reconstructions from the neighbouring peak of Nevado Firura reveal a smaller snowline depression, suggesting the glacial response to climate forcing in the tropics is strongly influenced by non-climatic factors. These data constitute some of the first directly dated palaeo-snowline data from the arid tropics and suggest that the magnitude of the last glaciation in at least parts of the tropical Andes was similar to late-Pleistocene events at higher latitudes. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Analysis of Holocene sediment accumulation in the Guadiana estuary (southern Portugal) during sea-level rise since ca. 13 cal. ka BP was used to simulate the long-term morphological evolution of the lower Guadiana estuary and the associated intertidal zone for 21st-century predicted sea-level rises. Three sea-level rise scenarios given by the IPCC ( 2007 ) were used in the simulations of morphology using a large-scale behaviour-oriented modelling approach. Sedimentation rate scenarios were derived both from the Holocene evolution of the estuary and from a semi-empirical estimation of present-day sediment aggradation. Our results show that the net lateral expansion of the intertidal zone area would be about 3–5% of the present intertidal zone area for each 10 cm rise in sea level. Under constraints imposed by the lack of fluvial sediment supply, the lateral expansion of the landward boundary of the intertidal zone will occur mainly in the Portuguese margin of the Guadiana estuary, while submergence of the salt marshes will occur in the Spanish margin. Therefore the Spanish margin is highly vulnerable to both sea-level rise and lack of sediment supply. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A combined geomorphological–physical model approach is used to generate three-dimensional reconstructions of glaciers in Pacific Far NE Russia during the global Last glacial Maximum (gLGM). The horizontal dimensions of these ice masses are delineated by moraines, their surface elevations are estimated using an iterative flowline model and temporal constraints upon their margins are derived from published age estimates. The equilibrium line altitudes (ELAs) of these ice masses are estimated, and gLGM climate is reconstructed using a simple degree–day melt model. The results indicate that, during the gLGM, ice masses occupying the Pekulney, Kankaren and Sredinny mountains of Pacific Far NE Russia were of valley glacier and ice field type. These glaciers were between 7 and 80 km in length, and were considerably less extensive than during pre-LGM phases of advance. gLGM ice masses in these regions had ELAs of between 575 ± 22 m and 1035 ± 41 m (above sea level) – corresponding to an ELA depression of 350–740 m, relative to present. Data indicate that, in the Pekulney Mountains, this ELA depression occurred because of a 6.4°C reduction in mean July temperature, and 200 mm a −1 reduction in precipitation, relative to present. Thus reconstructions support a restricted view of gLGM glaciation in Pacific Far NE Russia and indicate that the region's aridity precluded the development of large continental ice sheets. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A relative sea-level curve over the Holocene is constructed for the Young Sound region in northeastern Greenland. The reconstruction is derived by dating the heights of raised beach ridges in coastal plains using optically stimulated luminiscence (OSL), and by dating palaeoterrestrial surface levels now buried beneath the intertidal frame using the 14 C technique. The relative sea-level curve reveals a rapid fall of at least 10 mm a −1 from ca. 9500 to 7500 a ago, which slowed to 2 mm a −1 until it reached the present sea level ca. 3000 a ago. This part of the curve is based on the raised beach ridge data. Thereafter, relative sea level continued to fall, to reach a minimum level at about 0.5 m below the present sea level ca. 2300 a ago. Since then, relative sea level has experienced a slow rise of about 0.2 mm a −1 . This part of the curve uses the data from the palaeoterrestrial surfaces. The study supplements other estimates of Holocene relative sea-level changes and supports the observations of a decreasing trend in the timing of the cross point and in minimum relative sea level from South to North Greenland. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The Cova Gran de Santa Linya (Lleida, Spain) is a recently discovered site, with a broad chrono-cultural sequence that contains archaeological levels dating to the Middle Palaeolithic, Early Upper Palaeolithic, Late Upper Palaeolithic, Neolithic and Early Bronze Age. We present the chronometric and stratigraphic context of these occupations, which were dated using 14 C accelerator mass spectrometry and thermoluminescence. The sequence provides important indicators that aid in the reconstruction of the history of human occupation on the southern slopes of the Spanish Pyrenees over the past 50,000 years. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Tephra provides regional chronostratigraphical marker horizons that can link different climate archives with highly needed accuracy and precision. The results presented in this work exemplify, however, that the intermittent storage of tephra in ice sheets and during its subsequent iceberg transport, especially during glacial stages, constitutes a potential source of serious error for the application of tephrochronology to Nordic Seas and North Atlantic sediment archives. The peak shard concentration of the rhyolitic component of the North Atlantic Ash Zone II (NAAZ-II) tephra complex, often used to correlate marine and ice core records in Marine Isotope Stage (MIS) 3, is shown to lag the eruption event by ca. 100–400 years in some North Atlantic and Norwegian Sea cores. While still allowing for a correlation of archives on millennial timescales, this time delay in deposition is a major obstacle when addressing the lead–lag relationship on short timescales (years to centuries). A precise and accurate determination of lead–lag relationships between archives recording different parts of the climate system is crucial in order to test hypotheses about the processes leading to abrupt climate change and to evaluate results from climate models. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Several drill cores were obtained from a laminated, actively forming flowstone from a shallow cave in Austria. Highly resolved petrographic and geochemical analyses combined with multi-annual cave monitoring reveal a distinct sensitivity of flowstone growth and composition to late Holocene meteoric precipitation. The regular sub-millimetre-scale lamination consists of thicker, translucent laminae and thinner (organic) inclusion-rich laminae. There is also a macroscopic millimetre-scale banding of darker and lighter bands comprising several laminae. Stable isotope analyses of drill cores and modern calcite precipitates show a pronounced positive covariation of δ 13 C and δ 18 O values indicative of kinetic isotope effects. Comparing the isotope values with petrography shows gradual changes across several of the annual laminae, i.e. changes of several per mille on a multi-annual to decadal timescale. The stable isotope and trace-element composition, as well as the flowstone petrography, are mainly controlled by the variable drip-water discharge controlling the water-film thickness and water residence time on the flowstone surface and consequently the intensity of CO 2 -degassing, kinetic isotope enrichment and concomitant calcite precipitation. Drill core PFU6 provides an isotope record of the last ca. 3000 years at near-annual resolution. A distinct phase of low C and O isotope values – interpreted as increased discharge and hence higher meteoric precipitation – occurred from ca. 300 to 140 a b2k (second half of the Little Ice Age) and another wet interval occurred around 700 a, corresponding to reported Medieval glacier advances. The Roman Warm Period was also dominated by relatively wet conditions, although significant decadal variability prevailed. Increased precipitation further characterized the intervals from ca. 2480 to 2430 and 2950 to 2770 a. Dry conditions persisted during the Medieval Climate Anomaly, although this trend towards reduced precipitation started earlier. The highest C isotope values of the last 2 ka are recorded around 750 a and another dry phase is centred at 1480 a. This new record shows that inter-annual to decadal oscillations are a dominant mode of variation during the last 3 ka in the Alps. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We present a new palaeoenvironmental record of hydrological variability in Lake Baikal, based on re-modelled δ 18 O diatom values of diatom silica (δ 18 O modelled ), where the residual contaminants are identified and compensated for using electron optical imaging and whole-sample geochemistry. δ 18 O modelled interpretations are based on the balance between rivers with high δ 18 O values and rivers with low δ 18 O values. Isotopic variability is related to latitudinal differences in precipitation which feed these rivers. The δ 18 O modelled record suggests that rather moist conditions prevailed in the Lake Baikal region during the latter stages of the Younger Dryas. Throughout the Holocene, episodes of low δ 18 O modelled values are, in general, in good agreement with increases in percentage haematite-stained grains in North Atlantic sediments (indicative of ice-rafted debris events). Rivers with southerly catchments dominate fluvial input especially between c . 3.3 and 2 cal ka BP, concurrent with high precipitation in the Lake Baikal region. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The vegetational history of the penultimate glacial period, Marine Isotope Stage (MIS) 6 ( c . 185–135 ka), has remained relatively unexplored. Here we present a new record from the Ioannina basin, north-west Greece, which constitutes the highest-resolution terrestrial pollen record for this interval produced to date. It shows that the vegetation history of MIS 6 in this region can be divided into two parts: an early period (185–155 ka) with pronounced oscillations in tree population extent, and a later period (155–135 ka) with much smaller tree populations and subdued oscillations. This pattern is analogous to the MIS 3/MIS 2 division during the last glacial in the same sequence, although the early part of MIS 6 had larger Pinus populations and fewer temperate trees relative to the equivalent interval in MIS 3. This implies cooler and wetter conditions, which is somewhat counterintuitive given the high summer insolation during MIS 6e, but is in line with other palaeoclimatic evidence from the Mediterranean. Comparison with North Atlantic records suggests that despite the absence of pronounced iceberg discharges during MIS 6, North Atlantic millennial-scale variability had a significant downstream impact on tree populations in north-west Greece. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We present here the first paleotempestology record from Wassaw Island on the Georgia Bight, located in the south Atlantic coast of the United States. In the historical period, the Georgia Bight has experienced less frequent hits by hurricanes than other locations along the US Gulf and Atlantic coasts. The 1900-year record inferred from the overwash sand layers from a back-barrier marsh on Wassaw Island suggests that the island was directly struck by major storms on nine occasions during this interval. The Wassaw Island record shows alternating regimes, with periods of increased activity from 〉2000 a BP until ∼1100 a BP, and ∼100 a BP until the present, sandwiching a quiet period from ∼1100 to 250 a BP. Storm deposits from the most recent active period are perhaps amalgamated, indicating that site-specific conditions may result in event undercounting and suggests that the relative thickness of sand layers in the sedimentary record is not always indicative of hurricane strength. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A pollen diagram from a small peat bog on the island of Tristan da Cunha in the central South Atlantic (37°05'S,12°17'W) is presented. The pollen diagram contains data from both introduced and native plant taxa. The earliest pollen grains from introduced Plantago lanceolata are dated to around AD 1570, and probably represent unintentional introductions of weeds by the earliest Portuguese explorers visiting the islands. After AD 1600, a greater abundance of pollen from introduced plants and declining tree pollen values indicate opening of the lowland vegetation and more intense land use, probably attributable to the effect of seasonal seal and whale hunters. After AD 1800, evidence of increased erosion and more intense land use are inferred from the pollen diagram, reflecting permanent settlement. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A reconstruction of spring (April–May) temperature for northern Fennoscandia developed from the Tornionjoki (Tornio river) long cryophenological record of ice break-up dates, back to AD 1693, is presented. The record is strongly climatically sensitive and explains 67% of the variance in the instrumental data over the last 150 years. The record exhibits a stepped decrease in the duration of the river's ice cover by 14 days, equivalent to an increase in April–May mean temperature of approximately 2.5°C over the last three centuries. The relationship between the date of ice break-up, and accumulated daily mean temperatures (〉0°C) is investigated. Uncertainty in the observation of ice break-up is also considered in addition to the potential of this time series for regional climate model validation. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The U K 37 ′ index has proven to be a robust proxy to estimate past sea surface temperatures (SSTs) over a range of time scales, but like any other proxy, it has uncertainties. For instance, in reconstructions of the Last Glacial Maximum (LGM) in the northern North Atlantic, U K 37 ′ indicates higher temperatures than those derived from foraminiferal proxies. Here we evaluate whether such warm glacial estimates are caused by the advection of reworked alkenones in ice-rafted debris (IRD) to deep-sea sediments. We have quantified both coccolith assemblages and alkenones in sediments from glaciogenic debris flows in the continental margins of the northern North Atlantic, and from a deep-sea core from the Reykjanes Ridge. Certain debris flow deposits in the North Atlantic were generated by the presence of massive ice-sheets in the past, and their associated ice streams. Such deposits are composed of the same materials that were present in the IRD at the time they were generated. We conclude that ice rafting from some locations was a transport pathway to the deep sea floor of reworked alkenones and pre-Quaternary coccolith species during glacial stages, but that not all of the IRD contained alkenones, even when reworked coccoliths were present. We speculate that the ratio of reworked coccoliths to alkenone concentration might be useful to infer whether significant reworked alkenone inputs from IRD did occur at a particular site in the glacial North Atlantic. We also observe that alkenones in some of the debris flows contain a colder signal than estimated for LGM sediments in the northern North Atlantic. This is also clear in the deep-sea core studied where the warmest intervals do not correspond to the intervals with large inputs of reworked coccoliths or IRD. We conclude that any possible bias to U K 37 ′ estimates associated with reworked alkenones is not necessarily towards higher values, and that the high SST anomalies for the LGM are unlikely to be the result of a bias caused by IRD inputs. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Geochemical, mineralogical and biological indicators preserved in sediments are widely used to reconstruct past climate change, but proxies differ in the degree to which their utility as climate indicators has been validated via laboratory experiments, modern spatial calibrations, or down-core comparisons with instrumental climate data. Multi-proxy studies provide another means of evaluating interpretations of proxies. This paper presents a multi-proxy assessment comparing 19 sub-centennially resolved late Holocene proxy records, covering the period 300–1900 AD, from seven Icelandic marine and lacustrine core sites. We employ simple statistical comparisons between proxy reconstructions to evaluate their correlations over time and, ultimately, their utility as proxies for regional climate. Proxies examined include oxygen isotopic composition of benthic and planktonic foraminifera, abundance of the sea-ice biomarker IP 25 , allochthonous quartz in marine sediments (a proxy for drift ice around Iceland), marine carbonate abundance, total organic carbon concentration, chironomid assemblages, lacustrine biogenic silica and carbon/nitrogen ratios in lake sediments. Most of the examined proxy records, including temperature and sea-ice proxies, correlate strongly with each other over multi-centennial timescales, and thus do appear to record changes in regional climate. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The oxygen isotope signature (δ 18 O) of stalagmite SI3 collected from Shizi Cave in north-east Sichuan Province provides an Asian Summer Monsoon (ASM) record in Central China for the period 54–46 ka. The SI3 δ 18 O record clearly shows a negative δ 18 O excursion centred around 49.4 ka, which was reported in Hulu Cave in East China but not identified in the speleothem records from South-west China. As a whole, this record displays a higher coherence with the two Hulu records from East China than with the speleothem δ 18 O records from South-west China, suggesting that at 54–46 ka, Central China was influenced more by the East Asian Summer Monsoon than by the Indian Summer Monsoon. It also displays a significant negative δ 18 O excursion at 47.5–46.6 ka, which is not clearly documented in two other speleothem δ 18 O records previously reported from South-west China. This suggests that details of the Greenland interstadial 12 warrant further investigations in future in monsoonal China. The SI3 δ 18 O record displays more significant centennial-scale variations than the other four speleothem δ 18 O records from East and South-west China, which may be due to the fact that the study site is closer to the north-west boundary of the ASM and more sensitive to variations of the ASM than East and South-west China. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The use of macrofossil soil charcoal as a palaeoecological tool to reconstruct past vegetation, climate or fire history has gained much interest in recent years. Yet little is known about taphonomy of charcoal in soils. Here we assessed the putative loss of palaeoecological information due to charcoal fragmentation after burial. We found no significant loss of charcoal mass with time. Instead, we found a significant positive relationship between the mass of charcoal particles and their age. Permineralization of charcoal particles older than ca. 5200 a explained the increased charcoal mass with time in mineral soils. The permineralization process increased the density of charcoal particles (resulting in a twofold particles mass increase) and thus offers a protection against subsequent degradation. Our results suggest high stability of palaeoecological information from charcoal macrofossils buried in mineral soils at least over the Holocene timescale. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Nine tephra layers in marine sediment cores (MD99-2271 and MD99-2275) from the North Icelandic shelf, spanning the Late Glacial and the Holocene, have been investigated to evaluate the effectiveness of methods to detect tephra layers in marine environments, to pinpoint the stratigraphic level of the time signal the tephra layers provide, and to discriminate between primary and reworked tephra layers in a marine environment. These nine tephra layers are the Borrobol-like tephra, Vedde Ash, Askja S tephra, Saksunarvatn ash, and Hekla 5, Hekla 4, Hekla 3, Hekla 1104 and V1477 tephras. The methods used were visual inspection, magnetic susceptibility, X-ray photography, mineralogical counts, grain size and morphological measurements, and microprobe analysis. The results demonstrate that grain size measurements and mineralogical counts are the most effective methods to detect tephra layers in this environment, revealing all nine tephra layers in question. Definition of the tephra layers revealed a 2–3 cm diffuse upper boundary in eight of the nine tephra layers and 2–3 cm diffuse lower boundary in two tephra layers. Using a multi-parameter approach the stratigraphic position of a tephra layer was determined where the rate of change of the parameters tested was the greatest compared with background values below the tephra. The first attempt to use grain morphology to distinguish between primary and reworked tephra in a marine environment suggests that this method can be effective in verifying whether a tephra layer is primary or reworked. Morphological measurements and microprobe analyses in combination with other methods can be used to identify primary tephra layers securely. The study shows that there is a need to apply a combination of methods to detect, define (the time signal) and discriminate between primary and reworked tephra in marine environments. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Lago Puyehue is a glacigenic lake in the Chilean Lake District (40°S) with a complex deglaciation history. A detailed seismic–stratigraphic study of its sedimentary infill indicates a much earlier retreat of the glacier from the Lago Puyehue basin than the neighbouring glacier from the Lago Rupanco basin. Because of their close proximity, Rupanco meltwater streams played an important part in the depositional processes of Lago Puyehue. A timing discrepancy between the in-lake ages of a sediment core and the outer-lake ages of moraine deposits (re)opens the discussion on the timing of deglaciation in the Southern Hemisphere. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The wild horse Equus ferus was one of the most frequent species of the Late Pleistocene large ungulate fauna in Eurasia and played an important role in the subsistence of human groups, especially at the end the Late Glacial. It is frequently assumed that E. ferus became extinct in Europe at the beginning of the Holocene because of the development of woodlands and loss of open habitats. Because of its preference for open habitats and in spite of its adaptability, the appearance or disappearance of the wild horse could therefore be a suitable palaeoecological indicator for the opening of the Holocene primeval woodlands. We revised the dating and reliability of the subfossil record and dated several bones by atomic mass spectrometry 14 C dating. From the beginning of the Holocene (9600 cal a BC) to the end of the Atlantic Period (3750 cal a BC) there are 207 archaeological sites with wild horse records available in Europe. E. ferus survived the Pleistocene Holocene transition in Europe, but the spatiotemporal dynamics of populations fluctuated remarkably in the early and middle Holocene. Small and sparse populations increasingly became extinct during the early Holocene, until between 7100 and 5500 cal a BC the wild horse was almost absent in central parts of the European Lowlands. Particular conditions in natural open patches in the canopy forests, chalklands and floodplains may have maintained the local survival of the horse in some regions of the Lowlands, however. In the Late Atlantic, between 5500 and 3750 cal a BC the range of the wild horse was again extended. It re-immigrated into central and western Europe, probably as a consequence of increasing landscape opening by Neolithic peoples. The data presented here may be a valuable part of the debate on the degree of openness of the early and middle Holocene landscape. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Surging outlet glaciers are important in draining large ice caps, but the mechanisms controlling surge periodicities are poorly known. We investigated a sediment sequence from the glacier-fed Lake Lögurinn in eastern Iceland, and our unique annually resolved data, based on sedimentary varves, imply that Eyjabakkajökull, an outlet glacier of Vatnajökull, began surging about 2200 cal a BP (before 1950 AD). Approximately 1700 cal a BP, the glacier started to surge at a uniform 34- to 38-year periodicity that prevailed until the coldest part of the Little Ice Age when the periodicity almost halved to 21–23 years. Since the late 1800 s the surge periodicity of Eyjabakkajökull has returned to a longer period of 35–40 years. We suggest that surge periodicities of Eyjabakkajökull are forced by climatically driven mass balance changes, which may be a common forcing factor for similar surge-type outlet glaciers. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We present a multi-proxy reconstruction from a well-preserved vegetation surface (ca. 32 000 14 C a BP) from the Fox Permafrost tunnel near Fairbanks, Alaska. A thick litter layer of plant material on the vegetation surface is consistent with the vegetation lacking evidence of disturbance. Plant macrofossils and graminoid cuticle analysis show the presence of a graminoid assemblage consistent with phytolith data. The pollen data indicate that trees were not local to the site and that Artemisia sp. was present in the region. The insect and bryophyte reconstructions are consistent with the vascular plant reconstruction, indicating the site was at least periodically wet. δ 13 C values from the graminoids present show a large range encompassing both the wet and dry range displayed by modern graminoids in Alaska. Sequential δ 13 C analyses conducted along the length of leaves attached to the vegetation surface indicate a seasonal shift towards relatively higher water use efficiency. The lower water use efficiency earlier in the growing season may have stemmed from the use of winter season meltwater by plants at the site – a scenario consistent with the site's cryostratigraphy. Our multi-proxy reconstruction contributes to the limited palaeoecological data available for graminoid-dominated vegetation present in Eastern Beringia and particularly the interior of Alaska during the mid-Wisconsinan interstadial. Copyright © 2011 John Wiley & Sons, Ltd.

Description: To reconstruct the palaeoproductivity evolution history of the centre of the western Pacific warm pool (WPWP) over the last 250 ka, multi-proxies were analysed in sediment core WP7 recovered from the Ontong–Java Plateau. Palaeoproductivity evolution at the centre of the WPWP during the last 250 ka is closely related to glacial–interglacial cycles and the insolation controlled by precession. The glacial higher primary productivity relative to the interglacial conditions could have resulted from both thermocline shoaling associated with persistent El Niňo-like conditions and the increased influx of dust resulting from intensified winter monsoon together with important changes in the thermocline. The minimum primary productivity values during the last three terminations could be resulted from deglacial thermocline deepening and intensified stratification associated with persistent La Niña-like conditions, and the concurrent Neogloboquadrina dutertrei δ 13 C minimum events probably reflect the chemical signatures of Subantarctic Mode Water and Antarctic Intermediate Water. In addition, primary productivity values are also controlled by the thermocline variations resulting from El Niño/La Niña-Southern Oscillation processes responding to precession forcing, and lead the δ 18 O by about 4 ka. The 33.1 ka, 19 ka and “half-precession” periods are prominent in the palaeoproductivity records. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The upwelling region off northwest Africa is one of the most productive regions in the world ocean. This study details the response of surface- and deep-water environments off Mauritania, northwest Africa, to the rapid climate events of the last deglaciation, especially the Bølling–Allerød (15.5–13.5 ka BP) and Younger Dryas (13.5–11.5 ka BP). A high accumulation rate gravity core GeoB7926-2, recovered at ∼20° N, 18° W, was analysed for the grain size distribution of the terrigenous sediment fraction, the organic carbon content, diatom and benthic foraminifera communities. Humid conditions were observed during the Bølling–Allerød with a high contribution of fluvial sediment input. During the Younger Dryas intensified trade winds caused a larger sediment input of aeolian dust from the Sahara and more intense upwelling with higher primary productivity, as indicated by high diatom concentrations. The abrupt and large increase of organic matter caused low oxygen conditions at the sea floor, reflected by the poor benthic foraminiferal fauna and the dominance of the low-oxygen-tolerant foraminiferal species Bulimina exilis . This is surprising since low-oxygen conditions have not been recorded during modern times at the sea floor in this region, despite present-day intensive upwelling and high primary productivity. After the Younger Dryas, more humid conditions returned, diatom abundance decreased and B. exilis was replaced by typical deep-sea species as found in the region today, indicating the return of more oxygenated conditions at the sea floor. Copyright © 2011 John Wiley & Sons, Ltd.

Description: As the majority of the data on Quaternary sediments from the North Sea Basin are seismostratigraphical, we analysed the Elsterian Swarte Bank Formation, the Late Saalian Fisher Formation and the Late Weichselian (Dimlington Stadial) Bolders Bank Formation in order to determine genesis and provenance. The Swarte Bank Formation is a subglacial till containing palynomorphs from the Moray Forth and the northeastern North Sea, and metamorphic heavy minerals from the Scottish Highlands. The Fisher Formation was sampled from the northern and central North Sea. In the north, it is interpreted as a subglacial till, with glaciomarine sediments cropping out further south. These sediments exhibit a provenance signature consistent with the Midland Valley of Scotland, the Eocene of the North Sea Basin, the Grampian Highlands and northeast Scotland. The Bolders Bank Formation is a subglacial till containing palynomorphs from the Midland Valley of Scotland, northern Britain, and a metamorphic heavy-mineral suite indicative of the Grampian Highlands, Southern Uplands and northeast Scotland. These data demonstrate that there was repeated glaciation of the North Sea Basin during the Middle and Late Pleistocene, with ice sheets originating in northern Scotland. There was no evidence for a Scandinavian ice sheet in the western North Sea basin. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Marine palynomorph data paired with other indicators of sea-surface hydrography (planktic foraminiferal assemblages and oxygen isotopes) were used to decipher the impact of cold events on the northern Aegean region during the last glacial to interglacial transition. The data, which were derived from marine sediment cores GeoTü SL152 and GeoTü SL148, point to a strong impact of the Heinrich 1 and Younger Dryas cold events on surface-water conditions in the northern Aegean Sea. Shifts in marine palynomorph assemblages correlate with changes in terrestrial vegetation and climate (i.e. precipitation and temperature reconstructions based on pollen assemblages) in the northern borderlands of the Aegean Sea. The climate responses of the Aegean region to Heinrich event 1 (H1, ca. 17.5 to ca. 15.7 cal ka BP) and Younger Dryas (ca. 12.6 to ca. 11.7 cal ka BP) events appear similar in magnitude (with mean annual temperatures between ∼6 and 10°C and mean annual precipitation between ∼300 and ∼450 mm). However, the annual temperature decline during the H1 relative to the preceding already cold conditions was minor (〈3°C). The transition from the relatively warm and humid local equivalent of the Allerød interstadial to the Younger Dryas, on the other hand, witnessed an annual temperature decline of 6°C and an annual precipitation decrease of 300 mm, the latter occurring abruptly within only ca. 150 a. The return to warmer conditions in the northern Aegean region after the Younger Dryas was completed at ca. 11.6 cal ka BP. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Cosmogenic 10 Be surface exposure ages for bedrock sites around Torridon and the Applecross Peninsula in Wester Ross, northwest Scotland, provide new insights into the Lateglacial transition. Accounting for postglacial weathering, six statistically comparable exposure ages give a late Younger Dryas (G-1) exposure age of 11.8 ± 1.1 ka. Two further outliers are tentative pre-Younger Dryas exposure ages of 13.4 ± 0.5 ka in Torridon, and 17.5 ± 1.2 ka in Applecross. The Younger Dryas exposure ages have compelling implications for the deglaciation of marginal Loch Lomond Stadial ice fields in Torridon and Applecross. Firstly, they conflict with predictions of restricted ice cover and rapid retreat based on modelling experiments and climate proxies, instead fitting a model of vertically extensive and prolonged ice coverage in Wester Ross. Secondly, they indicate that 〉2 m of erosion took place in the upper valleys of Torridon and Applecross during the Younger Dryas, implying a dominantly warm-based glacial regime. Finally, the exposure ages have clarified that corrie (cirque) glaciers did not readvance in Wester Ross, following final deglaciation. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The Les Echets sediment sequence has recently been the subject of a high-resolution, multi-proxy study which revealed shifts in lake productivity linked to Greenland stadials and interstadials over the last 40 ka (Wohlfarth et al. , 2008 . Rapid ecosystem response to abrupt climate changes during the last glacial period in western Europe, 40–16 ka. Geology 36 : 407–410). Here we present new elemental data for this sequence as acquired using an X-ray fluorescence core scanning system which provides in situ high-resolution, continuous, multi-element analyses. It was found that the strength of associations between the studied elements (Ti, Rb, K, Zr, Si, Ca, Sr, Mn and Fe) varied over time with changes in lake status which are ultimately driven by changes in climate. Increases in fine-grained, detrital input (as indicated by Ti, Rb, K and Zr/Rb) overlap with independently established periods of lower lake productivity and are interpreted to represent more arid conditions. Several of these arid periods are coincident with low diatom concentrations and the timing of Heinrich events H4, H3 and H2. The duration of the environmental impacts linked to the H events varied by proxy with elemental data (Ti and Zr/Rb) estimating shorter events than the diatom data. Periods of lower detrital input and coarser grain sizes agreed in time with periods of higher lake productivity. The elemental data provide new insights into hydrological changes and related sediment processes within the catchment, and highlight the need for multi-element and multi-proxy approaches when reconstructing climate change using lacustrine sediment sequences. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Three pollen and charcoal records from three lakes lying at 3400 m elevation in southern Peru provided a record of landscape change spanning the last ca.18 000 cal. a BP. The tree line lay close to the site between ca. 16 000 and 12 000 cal. a BP, with Polylepis woodlands growing near the lakes. Progressively drying conditions led to increased fire after 12 000 cal. a BP, coinciding with a decline in Polylepis cover and Andean forest relicts as puna grasslands expanded. A strong decrease in the rate of sediment deposition between ca. 12 000 and ca. 4400 cal. a BP was interpreted to indicate the presence of sedimentary hiatuses. With the return of wet conditions after 4400 cal. a BP, forests did not reassemble around the lakes. Instead, fire-maintained grasslands dominated the landscape. Humans probably induced the intensified fire activity during the late Holocene and thereby deflected local successions. The modern fragmented landscape, with Polylepsis woodlands existing in fire-resistant pockets above the general limit of the Andean tree line, resulted from the intensification of human land use practices during the last 4400 cal. a BP. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Cumulative probability functions (CPFs) for large numbers of radiocarbon age determinations are increasingly being used by scientists as a methodology to discern environmental histories. While the recent compilation of regional databases of the radiocarbon dating control for fluvial sediment sequences has been beneficial for identifying gaps in knowledge and stimulating new research, there are a number of problems that critically undermine the use of these CPFs as sensitive hydroclimatic proxies. (i) The CPF method is underpinned by the assumption that each radiocarbon measurement is a true age estimate for a point in time, whereas each measured age in fact forms a scatter around the true age of the sample; (ii) calibration of radiocarbon ages is responsible for much of the structure in CPFs and compounds the problem of scatter and smears the chronological control; (iii) the databases incorporate multiple types of environmental changes differing chronological relationships between the 14 C measurements and the dated events, with pre-dating, dating or post-dating chronological control each displaying variable length temporal lags all mixed together in the same analysis; and (iv) the radiocarbon ages from individual case studies need to be more robustly tested before being incorporated into regional databases. All these factors negate the value of CPFs as sensitive proxies of environmental change, because peaks in probability for individual radiocarbon measurements are likely to be an incorrect estimate for the age of a geomorphological event and this problem is compounded by combining probabilities for multiple unrelated events. In this paper we present a critical analysis of CPFs and their interpretation before suggesting alternative approaches to analysing radiocarbon geochronologies of geomorphic events, which include: (i) Bayesian age modelling of river terrace development; (ii) developing regional databases that test specific geomorphic hypotheses; (iii) Bayesian age modelling of palaeoflood records; and (iv) analysis of sedimentation rates. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The Middle Pleistocene palaeoclimate and palaeoenvironment evolution of the Las Tablas de Daimiel wetlands is described using a combination of sedimentology, pollen and δ 13 C and δ 18 O isotopic records of Unit B of core LT-199906. This unit mostly contains fluvial and palustrine sediments. U/Th and amino acid racemization (AAR) dating and a comparison of the δ 18 O curve of Unit B with oceanic records suggests that Unit B spans the period from the end of Marine Isotope Stage (MIS) 10 (340 ka) to the first stages of MIS 7 (ca. 210 ka). MIS 9 was characterised by a regional vegetation dominated by Cupressaceae, with Pinus as a tree element. The water level was high and temperatures were very probably higher than during the Holocene. MIS 8 and the first substages of MIS 7 (7e, 7d and 7c) were dominated by xerophilous steppe vegetation in lowlands (elevations around 610 m above sea level) near to the wetland. At higher altitudes, far away from the wetland, there were fewer Pinus than in MIS 9, and a greater presence of warm, temperate and cool climate tree elements. The aquatic system in MIS 9 became shallower, with eutrophication and the accumulation of organic matter occurring; temperatures were similar to or lower than those of the Holocene. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Past fluctuations of the Antarctic ice sheet are poorly understood because of a lack of datable materials, radiocarbon reservoir ages and severe environments. Direct evidence of the timing of ice retreat is important in order to understand the Antarctic contribution to global sea-level rise since the Last Glacial Maximum. Here we report the first exposure ages constraining the timing of the last deglaciation from Lützow-Holm Bay, East Antarctica. Our data suggest that the final retreat of the ice sheet in the region occurred rapidly in the early Holocene and the reduction of the ice thickness in the region was at least 350 m. This occurred after the major Northern Hemisphere deglaciation. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The occurrence of pronounced climate reversals during the last glacial termination has long been recognised in palaeoclimate records from both hemispheres and from high to low latitudes. Accurate constraint of both the timing and magnitude of events, such as the Younger Dryas and Antarctic Cold Reversal, is vital in order to test different hypotheses for the causes and propagation of abrupt climate change. However, in contrast to higher-latitude regions, well-dated records from the Tropics are rare and the structure of late-glacial tropical climate remains uncertain. As a step toward addressing this problem, we present an in situ cosmogenic 3 He surface exposure chronology from Nevado Coropuna, southern Peru, documenting a significant fluctuation of the ice margin during the late-glacial period. Ten tightly clustered ages from a pair of moraines located halfway between the modern glacier and the Last Glacial Maximum terminus range from 11.9 to 13.9 ka and give an arithmetic mean age of 12.8 ± 0.7 ka (1 σ ). These data constitute direct evidence for a readvance, or prolonged stillstand, of glaciers in the arid Andes of southwestern Peru. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Floodplain deposition is an essential part of the Holocene sediment dynamics of many catchments and a thorough dating control of these floodplain deposits is therefore essential to understand the driving forces of these sediment dynamics. In this paper we date floodplain and colluvial deposition in the Belgian Dijle catchment using accelerator mass spectrometric radiocarbon and optical stimulated luminescence dating. Relative mass accumulation curves for the Holocene were constructed for three colluvial sites and 12 alluvial sites. A database was constructed of all available radiocarbon ages of the catchment and this database was analysed using relative sediment mass accumulation rates and cumulative probability functions of ages and site-specific sedimentation curves. Cumulative probability functions of ages were split into different depositional environments representing stable phases and phases of accelerated clastic deposition. The results indicate that there is an important variation between the different dated sites. After an initial stable early and middle Holocene phase with mainly peat growth in the floodplains, clastic sedimentation rates increased from 4000 BC on. This first phase was more pronounced and started somewhat earlier for colluvial deposits then for alluvial deposits. The main part of the Holocene deposits, both in colluvial and alluvial valleys, was deposited during the last 1 ka. The sedimentation pattern of the individual dated sites and the catchment-wide pattern indicate that land use changes are responsible for the main variations in the Holocene sediment dynamics of this catchment, while the field data do not provide indications for a climatological influence on the sediment dynamics. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Using results from coupled climate model simulations of the 8.2 ka climate event that produced a cold period over Greenland in agreement with the reconstructed cooling from ice cores, we investigate the typical pattern of climate anomalies (fingerprint) to provide a framework for the interpretation of global proxy data for the 8.2 ka climate event. For this purpose we developed an analysis method that isolates the forced temperature response and provides information on spatial variations in magnitude, timing and duration that characterise the detectable climate event in proxy archives. Our analysis shows that delays in the temperature response to the freshwater forcing are present, mostly in the order of decades (30 a over central Greenland). The North Atlantic Ocean initially cools in response to the freshwater perturbation, followed in certain parts by a warm response. This delay, occurring more than 200 a after the freshwater pulse, hints at an overshoot in the recovery from the freshwater perturbation. The South Atlantic and the Southern Ocean show a warm response reflecting the bipolar seesaw effect. The duration of the simulated event varies for different areas, and the highest probability of recording the event in proxy archives is in the North Atlantic Ocean area north of 40° N. Our results may facilitate the interpretation of proxy archives recording the 8.2 ka event, as they show that timing and duration cannot be assumed to correspond with the timing and duration of the event as recorded in Greenland ice cores. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We present a high-resolution record of lacustrine sedimentation spanning ca. 30 000 to 9000 cal. a BP from Onepoto maar, northern North Island, New Zealand. The multi-proxy record of environmental change is constrained by tephrochronology and accelerator mass spectrometric 14 C ages and provides evidence for episodes of rapid environmental change during the Last Glacial Coldest Period (LGCP) and Last Glacial–Interglacial Transition (LGIT) from northern New Zealand. The multi-proxy palaeoenvironmental record from Onepoto indicates that the LGCP was cold, dry and windy in the Auckland region, with vegetation dominated by herb and grass in a beech forest mosaic between ca. 28 500 and 18 000 cal. a BP. The LGCP was accompanied by more frequent fires and influx of clastic sediment indicating increased erosion during the LGCP, with a mid-LGCP interstadial identified between ca. 25 000 and 23 000 cal. a BP. Rapid climate amelioration at ca. 18 000 cal. a BP was accompanied by increased terrestrial biomass exemplified by the expansion of lowland podocarp forest, especially Dacrydium cupressinum . Increasing biomass production is reversed briefly by LGIT perturbations which are apparent in many of the proxies that span ca. 14 000–10 500 cal. a BP, suggesting generally increased wetness and higher in situ aquatic plant productivity with reduced terrestrial organic matter and terrigenous detrital influx. Furthermore, conditions at that time were probably warmer and frosts rare based on the increasing importance of Ascarina . The subsequent early Holocene is characterised by podocarp conifer forest and moist mild conditions. Postglacial sea-level rise breached the crater rim and deposited 36 m of estuarine mud after ca. 9000 cal. a BP. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A suite of deep-sea cores were collected along transects up to 100 km across the fore-arc and back-arc regions of the predominantly submarine Kermadec arc near Raoul and Macauley islands, southwest Pacific. The cores reveal a macroscopic tephra record extending back 〉50 ka. This is a significant addition to the dated record of volcanism, previously restricted to fragmented late Holocene records exposed on the two islands. The 27 macroscopic tephra layers display a wide compositional diversity in glass (∼50–78 wt% SiO 2 ). Many tephra layers comprise silicic shards with a subordinate mafic shard population. This could arise from magma mingling and may reflect mafic triggering of the silicic eruptions. Broadly, the glass compositions can be distinguished on diverging high-K and low-K trends, most likely arising from different source volcanoes. This distinction is also reflected in the tephra records exposed on Raoul (low-K) and Macauley (high-K) islands, the likely source areas. Heterogeneous tephra comprising shards of both high- and low-K affinity, silicic and mafic compositions, and more homogeneous tephra with subordinate outlier shard compositions, are best explained by post-depositional mixing of separate eruption deposits or contemporaneous eruptions. Evidently, the slow sedimentation rates of the calcareous oozes (∼10 1 –10 2  mm ka −1 ) were insufficient to adequately separate and preserve closely spaced eruption deposits. This exemplifies the difficulty in assessing eruption frequencies and magmatic trends, and erecting a tephrostratigraphy, using geochemical fingerprinting in such environments. Despite these difficulties, the ca. 5.7 ka Sandy Bay Tephra erupted from Macauley Island can be correlated over a distance of 〉100 km, extending east and west of the island, showing that the mostly submerged volcanoes are capable of wide tephra dispersal. Hence there is potential for developing chronostratigraphies for the southwest Pacific beyond the region covered by the extensive rhyolite marker beds from the Taupo Volcanic Zone. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Archaeological investigations undertaken along a proposed highway together with the compilation of available geological and pedological data made it possible to give a first overview of the distribution of Pleistocene aeolian deposits in south-west France. A chronological framework for deposition has been obtained using both radiocarbon ( n  = 24) and luminescence ( n  = 26) dating. It shows that aeolian transport was very active during the Late Pleniglacial, between 15 and ∼23 ka, leading to sand emplacement over a 13 000-m 2 area at the centre of the basin. The Pleniglacial coversands are typified by extensive fields of small transverse to barchanoid ridges giving way to sandsheets to the east. Subsequent aeolian phases, at ca. 12 ka (Younger Dryas) and 0.8–0.2 ka (Little Ice Age), correspond to the formation of more localized and higher, mainly parabolic dunes. At the southern and eastern margins of the coversand area, aeolian dust accumulated to form loess deposits, the thickness of which reaches ∼3 m on the plateaus. Luminescence dates together with interglacial-ranking palaeoluvisols between the loess units clearly indicate that these accumulations built up during the last two glacial–interglacial cycles. The chronology of sand and loess deposition thus appears to be consistent with that already documented for northern Europe. This suggests that it was driven by global climate changes in the northern hemisphere. The relatively thin aeolian deposits (and particularly loess) in south-west France is thought to reflect both a supply-limited system and a moister climate than in more northern and continental regions. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The fresh and saline lakes of Ounianga Kebir and Serir in northeastern Chad are among the very few permanent aquatic ecosystems currently existing in the hyper-arid core of the Sahara desert. The confirmed modern fauna of aquatic molluscs at Ounianga comprises three widespread species ( Melanoides tuberculata , Biomphalaria pfeifferi and Lymnaea natalensis ), of which only the first appears to maintain a thriving population. We recovered seven more species of gastropods, among which one is new to science ( Gabbiella ouniangaensis ), and one bivalve species from early Holocene outcrops of diatomaceous limestone at Ounianga Serir. All species except one are known to be commonly spread between lake and river systems by birds, and in its entirety this species-rich fossil mollusc fauna of Ounianga Serir resembles that of other Saharan lake sites known to have been hydrologically isolated during the early Holocene. The impoverished modern mollusc fauna, which lacks even the widespread and opportunistic species Bulinus truncatus , may have become established relatively recently through new colonisation events, following eradication of the early Holocene mollusc fauna during a later episode of high salinity or desiccation. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Beaufort's Dyke is a submarine depression located in the North Channel of the Irish Sea. With a maximum depth of 312 m, the dyke is one of the deepest areas within the European continental shelf. Integration and interpretation of 450 km of sparker seismic data and full-coverage bathymetric data derived from multi-beam echo sounder surveys allow for the investigation of the formation processes of Beaufort's Dyke and the evolution of geomorphological features within it. The dyke, formed by composite subglacial processes dominated by subglacial meltwater discharge, is interpreted as a tunnel valley. The regional isolation of Beaufort's Dyke may be explained by the bounding of the North Channel by the bedrock masses of Ireland and Scotland, coupled with the exploitation of structural weakness along a fault plane and presence of halite in the eroded substrate enhancing the erosive potential of the overlying glacier. Beaufort's Dyke has probably been maintained as an open feature by strong rectilinear tidal currents. The morphology of lunate sediment waves and a large parabolic bedform towards the south of the dyke contradict the observed dominant S–N mean hydrodynamic flow recorded within the North Channel, suggesting an alternative hydrodynamic regime either within the dyke or during bedform creation. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Discussions of dispersals of early hominins from Africa assume that Southwest Asia and the Arabian Peninsula were the primary passageways for migrations to Eurasia. The Mediterranean is usually viewed as a barrier to early hominin movements because pre- sapiens hominins were thought to lack the technical means or the cognitive skills to construct boats. The discovery of early Palaeolithic artefacts in an archaeological survey on the Greek island of Crete challenges this view. Here we show that Palaeolithic artefacts in the Plakias region in southwestern Crete are associated with geological contexts that can be dated to the late Middle or early Late Pleistocene. Because Crete has been separated from the mainland throughout the Pleistocene, the presence of Pleistocene age artefacts there suggests that early hominins were able to cross open water. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Holocene relative sea level (RSL) changes have been investigated by analysing and dating isolation sequences from five lakes near Sisimiut in south-western Greenland. The transitions between marine and lacustrine sediments were determined from elemental analyses and analyses of macroscopic plant and animal remains. Radiocarbon dating was used to provide minimum ages for the transitions and to construct a RSL curve. Dating of a shell of the marine bivalve Macoma balthica indicates that deglaciation of the lowlands occurred in the early Holocene, at around 10 900 cal a BP. The RSL curve shows initial rapid regression from the marine limit at around 140 m, implying strong glacio-isostatic rebound. We suggest that the margin of the Greenland Ice Sheet was located at the shelf break during the Last Glacial Maximum. Frequent remains of the ostracode Sarcypridopsis aculeata , which is a thermophilous brackish water species that is unknown from the extant fauna of Greenland, in one of the basins around 8500 cal a BP may mark the beginning of the Holocene thermal maximum in the region. Copyright © 2011 John Wiley & Sons, Ltd.

Description: The emerging tephrostratigraphy of NW Europe spanning the last termination (ca. 15–9 ka) provides the potential for synchronizing marine, ice-core and terrestrial records, but is currently compromised by stratigraphic complications, geochemical ambiguity and imprecise age estimates for some layers. Here we present new tephrostratigraphic, radiocarbon and chironomid-based palaeotemperature data from Abernethy Forest, Scotland, that refine the ages and stratigraphic positions of the Borrobol and Penifiler tephras. The Borrobol Tephra (14.14–13.95 cal ka BP) was deposited in a relatively warm period equated with Greenland Interstadial sub-stage GI-1e. The younger Penifiler Tephra (14.09–13.65 cal ka BP) is closely associated with a cold oscillation equated with GI-1d. We also present evidence for a previously undescribed tephra layer that has a major-element chemical signature identical to the Vedde Ash. It is associated with the warming trend at the end of the Younger Dryas, and dates between 11.79 and 11.20 cal ka BP. Copyright © 2011 John Wiley & Sons, Ltd.

Description: High-resolution climatic records of the late Holocene along the north-west African continental margin are scarce. Here we combine sediment grain size, elemental distribution and mineral assemblage data to trace dust and riverine sources at a shallow-marine sediment depocentre in the vicinity of the Senegal River mouth. The aim is to understand how these terrigenous components reflect climate variability during the late Holocene. Major element contents were measured and mineral identification was performed on three sub-fractions of our sediment core: (i) fluvial material 〈 2 µm, (ii) aeolian material of 18–63 µm and (iii) a sub-fraction of dual-origin material of 2–18 µm. Results show that more than 80% of the total Al and Fe terrigenous bulk content is present in the fluviogenic fraction. In contrast, Ti, K and Si cannot be considered as proxies for one specific source off Senegal. The Al/Ca ratio, recording the continental river runoff, reveals two dry periods from 3010 to 2750 cal a BP and from 1900 to 1000 cal a BP, and two main humid periods from 2750 to 1900 cal a BP and from 1000 to 700 cal a BP. The match between (i) intervals of low river runoff inferred by low Al/Ca values, (ii) reduced river discharge inferred by integrated palynological data from offshore Senegal and (iii) periods of enhanced dune reactivation in Mali confirms this interpretation. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We compare lake and alluvial stratigraphy along a frame connecting the southern Alpine foothills and the Adriatic Sea, with the aim of matching the effects of Alpine glaciation and sea-level changes on sedimentation during the last glacial cycle. The palynostratigraphy of Lake Fimon provided proxies for regional vegetation and climate change and was coupled with sediment petrography, loss on ignition and magnetic susceptibility, disentangling alluvial phases from fluvioglacial activity related to culminations of the southeastern Alpine glaciers. The Fimon area was not reached by alluvial fans during the penultimate glacial maximum, nor by the sea transgression during the last interglacial, but a closed lake soon developed at the Eemian onset due to enhanced rainfall. Sea-level fall at glacial inception triggered the entrenchment of the drainage network in the plain reaching the outer Fimon Basin. Slow aggradation, but no sign of fluvioglacial activity, lasted to 38.2 ± 1.45 cal. ka BP, when a major forest withdrawal took place, coeval to the spread of alluvial fans. By 27.5 ± 0.5 cal. ka BP the Fimon Basin was dammed by the Brenta outwash system. The main step of of forest recovery commenced at around (15.8) cal. ka BP, when apex trenching of the outwash fans was triggered by the glacier's decay. Copyright © 2011 John Wiley & Sons, Ltd.

Description: A pollen-inferred vegetation shift, from pioneer birch–pine woodland to mixed pine–summergreen oak forests, in the southern Alpine forelands, is commonly attributed to a centennial-scale warming that occurred between the Gerzensee Oscillation (GO) and the Younger Dryas. Two microtephra layers bracketing the Younger Dryas onset (the Laacher See Tephra and the Vedde Ash) improve the chronology at Lago Piccolo di Avigliana (northern Italy) and allowed accurate correlation with Central European records where the GO is clearly detected. We used pollen percentages, pollen accumulation rates (PARs) and plant macrofossils to assess the population dynamics of Quercus , and leaf-cuticle analysis for a better taxonomic identification of Quercus . Our results indicate that the species that was locally present was probably Quercus robur . PARs suggest that the population expansion started as early as the Bølling and followed an exponential increase through time. We attribute this gradual shift to increasing summer temperatures and longer growing seasons which contrast with a gradually decreasing temperature trend as recorded in Greenland ice cores and in Central Europe. Breaks or set-backs in the PAR record may indicate the biotic response to minor Lateglacial cooling events of different life-history stages in the Quercus population. Copyright © 2011 John Wiley & Sons, Ltd.

Description: We present 10 in situ cosmogenic exposure ages from two moraines on the Isle of Skye. The Strollamus medial moraine was deposited during deglaciation of the Devensian ice sheet and yields a mean exposure age from five samples of 14.3 ± 0.9 ka. The moraine age indicates that a significant ice mass existed on Skye at the time of a regional readvance recorded in Wester Ross, northwest Scotland. Taken at face value the ages suggest that deglaciation did not occur until well into Greenland Interstade 1. The Slapin moraine represents the local limit of the Loch Lomond Readvance (LLR) and yields a mean exposure age from five samples of 11.5 ± 0.7 ka, which is consistent with deposition relating to the LLR. These ages suggest that the maximum extent may have been reached late in the stadial and that some glaciers may have remained active until after the climatic amelioration that marks its end. This scenario is considered unlikely given the nature of the climate during this period, which leads us to call for a locally calibrated production rate. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Vertical land motion caused by continuing glacial isostatic adjustment is one of several important components of sea-level change and is not limited just to previously glaciated regions. A national-scale analysis for the British Isles shows an ellipse of present-day relative uplift (relative sea-level fall), ∼1.2 mm a −1 , broadly centred on the deglaciated mountains of Scotland. The pattern of three foci of relative subsidence, ∼1 mm a −1 , results from the additional interactions of the deglacial meltwater load on the Atlantic basin and the continental shelf, and the signal due to far-field ice sheets. At a local scale, sediment compaction can more than double the rate of relative land subsidence. Relative land-level change (the negative of relative sea-level change) is not the same as vertical land motion. There is a spatial pattern in the difference between relative land-level change and vertical land motion, with differences at present of approximately −0.1 to −0.3 mm a −1 around the British Isles and +2.5 to −1.5 mm a −1 globally. For the wider scientific and user community, whether or not the differences are considered significant will depend upon the location, time frame and spatial scale of the study that uses such information. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Precipitation has been of utmost importance in shaping the evolution of landscapes and human settlements in the Mediterranean. However, information on seasonal precipitation patterns through the Holocene is scarce. This study attempts to quantify the evolution of seasonal precipitation in the East Iberian Peninsula (5000 BC to AD 600) based on the carbon isotope composition (δ 13 C) of archaeobotanical remains. Data on Holm oak, Aleppo pine and small-grain cereals were combined, and precipitation was inferred from models relating present-day records to the δ 13 C of modern samples. Subsequently, charred grains were used as a proxy for ancient moisture during April–May, whereas oak and pine charcoals provided complementary rainfall estimates for September–December and January–August, respectively. The results reveal aridity changes throughout the Holocene in the western Mediterranean. Past spring–summer precipitation was consistently higher than at present. In contrast, autumn and early winter precipitation showed stronger fluctuations, particularly during the first millennium BC, and often exhibited values below those of the present. The high contribution of autumn precipitation to the annual water budget, typical of the present Mediterranean climate, was definitively established at the beginning of the current era. This study shows how a combination of species holding complementary environmental signals can contribute to a wider knowledge of local precipitation dynamics. Copyright © 2011 John Wiley & Sons, Ltd.

Description: High-resolution multi-proxy analyses of a sediment core section from Lake Jeserzersee (Saissersee) in the piedmont lobe of the Würmian Drau glacier (Carinthia, Austria) reveal pronounced climatic oscillations during the early late glacial (ca. 18.5–16.0k cal a BP). Diatom-inferred epilimnetic summer water temperatures show a close correspondence with temperature reconstructions from the adjacent Lake Längsee record and, on a hemispheric scale, with fluctuations of ice-rafted debris in the North Atlantic. This suggests that North Atlantic climate triggered summer climate variability in the Alps during the early late glacial. The expansion of pine (mainly dwarf pine) between ca. 18.5 and 18.1k cal a BP indicates warming during the so-called ‘Längsee oscillation’. The subsequent stepwise climate deterioration between ca. 18.1 and 17.6k cal a BP culminated in a tripartite cold period between ca. 17.6 and 16.9k cal a BP with diatom-inferred summer water temperatures 8.5–10 °C below modern values and a shift from wet to dry conditions. This period probably coincides with a major Alpine glacier advance termed the Gschnitz stadial. A warmer interval between ca. 16.9 and 16.4k cal a BP separates this cold phase from a second, shorter and less pronounced cold phase between ca. 16.4 and 16.0k cal a BP, which is thought to correlate with the Clavadel/Senders glacier advance in the Alps. The following temperature increase, coupled with wet (probably snow-rich) conditions, caused the expansion of birch during the transition period to the late glacial interstadial. Copyright © 2011 John Wiley & Sons, Ltd.