ALBERT

Description: In the UK, a combination of outcrop mapping, satellite digital elevation models, high-resolution marine geophysical data and a range of dating techniques have constrained the maximum limit and overall retreat behaviour of the British and Irish Ice Sheet (BIIS). The changing styles of deglaciation have been most extensively studied in the west and north-western sectors of the BIIS, primarily using offshore geophysical surveys. The surviving record in the southern, terrestrial sector is fragmentary, permitting only large-scale (tens of kilometres) and longer timescale ( c . 1 ka) reconstructions of ice-margin movement, with limited information on deglacial processes. Here we present a high-resolution study of the retreat behaviour for a section of the southern ice-margin from Windermere in the Lake District, using high-resolution two-dimensional multi-channel seismic data, processed using prestack depth migration. By combining the seismic stratigraphy with landform morphologies, extant cores and seismic velocity measurements, we are able to distinguish between: over-consolidated till; recessional moraines; De Geer moraines; flowed till/ice-front fan; supra-/en-glacial melt-out till; and subsequent glaciolacustrine/lacustrine sedimentation. The results reveal a complex and active valley glacier withdrawal from Windermere that changed character between basins and produced two small, localized areas of ice-stagnation and downwasting. This study indicates that similar active ice-margin retreats probably took place in other valleys of the Lake District during the Late Devensian deglaciation rather than the previously held view of rapid ice-stagnation and downwasting. When combined with the regional terrestrial record, this supports a model of early ice loss in terrestrial England compared with other parts of the UK. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Compound specific hydrogen isotopic compositions ( δ D) of free and bound forms of n -fatty acids (FA) were measured throughout a 200 m sediment core taken from Lake Biwa to assess application of biomarker δ D values to paleoclimate study in this central Japan lake. The results of our study suggest that the sources of the C 16 n -FA in the two forms are different, whereas both free and bound C 28 n -FA originate from terrestrial plants. The δ D of combined (free plus bound) C 28 n -FA in the 200 m sediment core shows a large variability, with relatively low and high values during the glacial and interglacial periods, respectively. Based on comparison of our record with other marine and lacustrine paleoclimate data, we found that the sedimentary record of C 28 n -FA δ D likely reflects the temperature-induced change in δ D of summer precipitation. This finding suggests that δ D values of C 28 n -FA could be used as a proxy for summer paleotemperatures in the sediments of Lake Biwa and other lakes. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Published annual-to-decadal-resolution stalagmite δ 18 O records since AD 900 from six caves (Dongge, Furong, Heshang, Buddha, Shihua and Wanxiang) in China were analyzed to detect temporal and spatial variability of the East Asian Summer Monsoon strength, which strongly affects wet/dry conditions in eastern China. The empirical mode decomposition method was used to obtain trends of the six cave records. After the base trend was determined, δ 18 O anomalies of each record were computed by subtracting the base trend. Mean δ 18 O anomaly values of the detrended time series for each cave record were calculated for four periods: (i) Medieval Warm Period (MWP; AD 900–1250): (ii) Little Ice Age phase 1 (LIA-1; AD 1250–1550); (iii) Little Ice Age phase 2 (LIA-2; AD 1550–1850); and (iv) modern period (MD; AD 1850–2000). From these anomalies, the temporal and spatial variability of wet/dry conditions has been identified. Positive values of the mean δ 18 O anomalies indicating drier conditions appeared in the lower Yangtze River Drainage Area and Southeast Coast Area during MD-1, LIA-1 and MWP, whereas negative values existed in north, south and Yangtze areas of eastern China during LIA-2. The results agree with the dryness/wetness index reconstructed by Chinese historic records in general. These results illustrate that wet and dry conditions in different regions of eastern China could be opposite under monsoon influence, so that no single speleothem δ 18 O record could represent the monsoonal climate in this vast region. Climatic patterns in the monsoonal region can be either a combination of warm/wet and cold/dry or a combination of cold/wet and warm/dry on annual-to-centennial scales. A 128-year periodic cycle exists in all six cave records, whereas 64-year (possibly a harmonic of 128-year periodicity) and 42-year periodicities appear in Shihua, Heshang and Dongge records. These cycles may reflect the influence of solar activity on the East Asian Summer Monsoon. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Paleoceanographic changes in the East/Japan Sea during the late Quaternary based on high-resolution elemental variations, particularly correlations between dark–light laminations and millennial-scale climatic changes, have remained poorly understood because of the lack of the high-resolution proxies. The recent application of micro-X-ray fluorescence (XRF) core scanning provides the potential for high-resolution study on the laminations deposited in the East/Japan Sea. In this study, we present a geochemical study by using micro-XRF core scanning on a 730 cm core recovered from the East/Japan Sea. Elemental variations and factor analysis indicate that the sedimentary environment changed from anoxic to suboxic conditions from Marine Isotope Stage (MIS) 2–3 to MIS 1, which is induced by increased contribution of high-salinity sea water from the open ocean due to the rising sea level. The dark and light laminations during MIS 2–3 were correlated with Dansgaard–Oeschger cycles and summer monsoon proxy, with dark-colored sediments related to higher terrigenous concentration, corresponding to warm–moist and enhanced summer monsoon period. During the interstadial period, more terrigenous sediments were transported to the East/Japan Sea via the strengthened fluvial discharge from the surrounding continents, caused by enhanced monsoon rainfall. Thus the development of the East Asian summer monsoon and consequent variations in fluvial discharge would have significantly affected the paleoceanographic conditions in the East/Japan Sea during the MIS 2–3 sea-level lowstand. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Based on elemental geochemical data, we reconstructed the sediment provenance, surface productivity and bottom water redox conditions for the last 48 ka in the Ulleung Basin (Sea of Japan) and inferred the factors controlling them. Al 2 O 3 /TiO 2 ratio and chemical index of alteration (CIA) suggest that sediment provenance changed during the glacial period (48–18 ka) compared to the deglacial (ca. 18–11 ka) and Holocene. Mass accumulation rates of total organic carbon (TOC), CaCO 3 , phosphorus, cadmium and excess barium reveal low paleoproductivity during low sea stand. During 18–11 ka, productivity increased due to increasing inflow of nutrient-rich water masses – the Oyashio and the East China Sea coastal water – in tandem with the rising sea level. Maximum productivity occurred during Younger Dryas and Pre-boreal periods when sea level was at ∼ −60 m and then gradually decreased as the Tsushima Warm Current inflow kicked off at ca. 9.3 ka, consistent with other paleoredox proxies, which reveal the presence of anoxic bottom water during ca. 12–9 ka. With the changes in paleoredox proxies and their ratios (TOC, Mo, U, Mn, C/S ratio and U authigenic and Mo contents), we hypothesized that the redox changes were mainly ventilation driven and were superimposed on the influence of circulation-induced productivity changes. The global climate and sea-level changes on a millennial timescale play a major role in enhancing paleoproductivity and restrict bottom water advection, subsequently driving the oxygenation of bottom water in the Ulleung Basin. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The Japan Sea is connected with the Okhotsk Sea and Northwest Pacific through three straits, viz. Mamiya (Tartarskiy), Soya and Tsugaru, and with the East China Sea through Tsushima Strait, all having sill depths of 〈140 m. Therefore, the Japan Sea was almost isolated from the surrounding seas during the Last Glacial Maximum (LGM; ca. 20 ka). As a result of nearly broken communication with the surrounding seas and strengthened surface stratification due to locked fresh water in the basin during the LGM, it became an anoxic basin. This major shift in the surface water properties of the basin left its imprint in the oxygen isotopic composition (δ 18 O PF ) of the planktonic foraminifera. The δ 18 O PF exhibits extremely low values (∼0.5‰ vs. Belemnite from Pedee formation, South Carolina: PDB) during the last two glacial maxima, ca. 20 ka (Marine Isotope Stage (MIS) 2.2) and ca. 140 ka (MIS 6.2). These decreases are in contrast to the expected generally high glacial values of 〉3‰ recorded in the MIS 3–4 sections of the studied cores. This observation indicates nearly similar surface water conditions in the Japan Sea during both the previous glacial maxima, and hence suggests negligible effect of strait tectonics on the sea level since the last 140 ka. Low δ 18 O PF values with small amplitude are also observed at the cold stage MIS 6.4, but not observed at another cold stage MIS 4.2. This observation suggests that the low-salinity surface water in the Japan Sea started to develop at the sea level between MIS 4.2 and 6.4. Judging from the cross-section of the Tsushima Strait and the sea floor topography of the East China Sea, the sea level between MIS 4.2 and 6.4 must have been between 90 m and 100 m below the present. From a proportional relationship between the standard δ 18 O curve (LR04) in deep-sea cores and globally averaged sea-level change, the eustatic sea level obtained for the LGM is 120 ± 7 m below the present. Thus the Japan Sea, in a far-field location from the continental ice sheets, provides an important clue for estimation of the eustatic sea level at the LGM. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Current surface production in the Banda Sea is primarily controlled by monsoonal forcing, the strength of the Indonesian throughflow and surface salinity, and is sensitive to global climate changes. Therefore, variations of paleoproductivity represented by the abundance of diatoms are estimated to assist in understanding possible hydrological changes during glacial–interglacial cycles since Marine Isotopic Stage 11 (MIS 11). During the interglacials, the enhanced austral winter monsoon (southeast monsoon) encourages deepening of the mixed layer and uplifting of the thermocline, thereby increasing surface production. However, accompanied enhancement of the Indonesian throughflow (ITF) within the interglacials brings warm and less-saline water from the central part of the warm pool water entering the Banda Sea to mitigate development of the upwelling system. Conversely, cooling of the Northern Hemisphere forces the strengthening of the austral summer monsoon (northwest monsoon) to depress the upwelling and reduce production during glacial intervals, whereas the weakening flow of the ITF reduces the influence of low-salinity capping effects and benefits production. Higher abundance of Chaetoceros sp., dominant in upwelling environments, observed in glacials suggests that strength of the ITF is the most important factor in controlling the vertical thermostructure of the Banda Sea. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The Australian summer monsoon (ASM) is primarily a synoptic feature determined by the differential thermal response to solar insolation between the Australian continent and the western Pacific warm pool (WPWP) in austral summer. Little is known about the process involved in driving long-term ASM variability. Here we present a 180 ka record of terrestrial fluxes into offshore southeastern Papua New Guinea (PNG), a prevailing monsoon area in the WPWP. Terrestrial fluxes were estimated by a 230 Th-normalized method, indicating higher terrestrial inputs into the ocean during glacial stages. We argue that the higher terrestrial fluxes are mainly fluvial, which in turn are linked to stronger ASM precipitation on land, though the increased terrestrial flux could possibly also be due to the lowstand or glacial erosion of mountain glaciers. Cross-spectral analysis indicates that the ASM precipitation maxima are controlled by local summer insolation maxima, WPWP sea-surface temperature minima and East Asian winter monsoon (EAWM) maxima in precession frequency bands (21 ka −1 ). This result suggests that the 21 ka components of the ASM in the past 180 ka are not only insolation driven but also a dynamic component strengthened by cross-hemispheric pressure gradient resulted from the precession maxima forcing. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The purpose of this study is to improve prehistoric knowledge of paleo-typhoon and winter monsoon activity in the western North Pacific after 8 cal. ka BP. We examine two sediment cores derived from lakes located to the south and north of the Ilan Plain in northeastern Taiwan. Seasonal and typhoon rainfall data over the past several decades are collected for this study region. We also use mineral indicators, K/Rb ratios and grain size to estimate sediment sources, intensity of chemical weathering and rainfall intensity. The results show that the chemical weathering index (K/Rb ratio) of Meihua Lake indicates the continuing effects of autumn rainfall, while coarse grain sizes of Dahu Lake sediments suggest increased intensity in typhoon rainfall. Grain size results reveal that increasing El Niño–Southern Oscillation intensity in the tropical Pacific has intensified the activity of super typhoons in the western North Pacific. Finally, we find that frequent activity of super paleo-typhoons occurred in Taiwan during the La Niña-like state, and the strengthening winter monsoon activity and higher sea surface temperature enhanced plentiful autumn rainfall in El Niño-like state. After comparing our results with the paleo-typhoon data in Japan and south China, we suggest that the tracks of super typhoon are mainly affected by variations in the warm pool and subtropical Northwestern Pacific High in the western Pacific. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Glacial cooling (∼1–5°C) in the eastern equatorial Pacific (EEP) cold tongue is often attributed to increased equatorial upwelling, stronger advection from the Peru–Chile Current (PCC), and to the more remote subpolar southeastern Pacific water mass. However, evidence is scarce for identifying unambiguously which process plays a more important role in driving the large glacial cooling in the EEP. To address this question, here we adopt a faunal calibration approach using planktic foraminifers with a new compilation of coretop data from the eastern Pacific, and present new downcore variation data of fauna assemblage and estimated sea surface temperatures (SSTs) for the past 160 ka (Marine Isotope Stage (MIS) 6) from ODP Site 1240 in the EEP. With significant improvement achieved by adding more coretop data from the eastern boundary current, our downcore calibration results indicate that most of the glacial cooling episodes over the past 160 ka in the EEP are attributable to increased influence from the subpolar water mass from high latitudes of the southern Pacific. By applying this new calibration of the fauna SST transfer function to a latitudinal transect of eastern Pacific (EP) cores, we find that the subpolar water mass has been a major dynamic contributor to EEP cold tongue cooling since MIS 6. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Variations in stable carbon isotopic compositions of n -alkanes (δ 13 C alk ) and n -alkane proxies (CPI, C 31 /C 27 and ACL) from core MD05-2905 (20° 08.17′ N, 117° 21.6′ E) in the northern South China Sea (SCS), provided evidence of biological responses on adjacent land areas in the form of changes in terrestrial vegetation and provenance of the remains of land plants during and since the Last Glacial Maximum (LGM). Decreased values of n -alkane proxies and δ 13 C alk over the last 28 ka marked the transition from glacial to interglacial conditions and indicated a greater extent of herbaceous vegetation at the LGM than present and an increased abundance in woody vegetation during the Holocene. Relatively larger δ 13 C alk values at the LGM indicated that n -alkanes of terrestrial herbs in the sediment core were not only from the leaf waxes of C 3 plants, such as herbs of Artemisia , growing on proximate parts of the exposed continental shelf, but also from C 4 grasses likely from subtropical parts of southeastern China and Taiwan Island. Reconstructed sea-surface temperatures (SSTs), based on data from the same core, revealed that temperatures were ∼3°C lower than present during the LGM, with abrupt variations during both glacial and interglacial periods. During the LGM, lower temperature and sea level and greater aridity relative to present resulted in an expansion of herbaceous vegetation over an enlarged extent of exposed continental shelf. Following deglaciation, warming and enhanced summer monsoonal activity led to increased humidity and to an expansion of woody vegetation (mostly C 3 plants) during the Holocene. Results also revealed rapid oscillations in C 31 /C 27 ratios over millennial scales, with lower values associated with cold stages. These low C 31 /C 27 ratios indicated increased input of woody plant material possibly from more extensive gallery forest and greater transport of their plant debris to the coring site, perhaps facilitated by enhanced runoff under a strengthened Northern Hemisphere winter monsoon during short-duration cold events. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The East China Sea (ECS) responds to changes in the strength of the Kuroshio and East Asian monsoon activity. Multidecadal resolution records of the palaeotemperature indices and from core KY07-04 PC-1 show that the hydrology of the ECS responded to variability in the East Asian winter monsoon. Unlike Mg/Ca-derived sea surface temperatures, which show neither warming nor cooling trends during the Holocene, the record showed a general warming trend at a rate of 0.2°C ka −1 . This warming was attributable to shrinkage of the Yellow Sea Central Cold Water and/or weaker winter cooling of the surface water. The record indicated a centennial-scale variability with an ∼1°C amplitude superimposed on the warming trend that reflected changes in the East Asian winter monsoon and/or the Kuroshio. Temperature minima appeared at ca. 3.0, 4.7, 6.2, 7.9 and 9.0 ka, and spectral analysis of the last 7 ka revealed significant peaks with periodicities of approximately 210, 250, and 440 years that were close to those observed in solar radiation. The reconstructed winter monsoon variability is consistent with Chinese documentary records for the last two millennia. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The absence of human occupation sites in southeastern Brazil during the mid Holocene has been referred to as the 'Archaic Gap' (8970–1940 cal. a BP) and is predicted to have resulted from increased aridity. A ca. 14 000 cal. a pollen history from two well-dated lake sediment cores located within the archeological district of Lagoa Santa, in the State of Minas Gerais, southeastern Brazil, was used to test this hypothesis. Our analyses indicated that the present cerrado and tropical semi-deciduous forest mosaic persisted throughout the mid Holocene, until ca. 5500 cal. a BP, and the Lagoa Santa region did not experience especially dry conditions during the Holocene period. The early Holocene pollen spectra contained an assemblage of cold-adapted taxa such as Podocarpus , Myrsine and Araucaria , co-occurring with taxa from cerrado, e.g. Caryocar . A replacement of cold taxa by the modern cerrado–semi-deciduous forest vegetation took place progressively, but appears to have been completed by the mid Holocene. No evidence of sustained drought was found in sedimentation or forest composition, nor any prolonged dry event in the study region. Holocene dryness as an explanation for the abandonment of Lagoa Santa region is not supported by the palynological analyses conducted in this study. Rather it is suggested that unpredictable climate may have underlain that abandonment. Copyright © 2012 John Wiley & Sons, Ltd.

Description: A multi-proxy record is presented for approximately the last 4500 cal a BP from Lake Shkodra, Albania/Montenegro. Lithological analyses, C/N ratio and δ 13 C of the organic and inorganic carbon component suggest that organic matter and bulk carbonate are predominantly authigenic. The δ 18 O record of bulk carbonate indicates the presence of two prominent wet periods: one at ca. 4300 cal a BP and one at ca. 2500–2000 cal a BP. The latter phase is also found in southern Spain and Central Italy, and represents a prominent event in the western and central Mediterranean. In the last 2000 years, four relatively wet intervals occurred between ca. 1800 and 1500 cal a BP (150–450 AD), 1350–1250 (600–700 AD), 1100–800 (850–1150 AD), and at ca. 90 cal a BP (1860 AD). Between ca. 4100 and 2500 cal a BP δ 18 O values are relatively high, with three prominent peaks indicating drier conditions at ca. 4100–4000 cal a BP, ca. 3500 and at ca. 3300 cal a BP. Four additional drier events are identified at 1850 (ca. 100 AD), 1400 (ca. 550 AD), 1150 (800 AD) and ca.750 cal a BP (1200 AD). The pollen record does not show changes in accordance with these episodes owing to the poor sensitivity of vegetation in this area, which is dominated by an orographic rainfall effect and where changes in altitudinal vegetation belts do not affect the pollen rain in the lake catchment. However, since ca. 900 cal a BP a significant decrease in the percentage arboreal pollen and in pollen concentrations suggest major deforestation produced by human activities. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Alternative, established models for the deglaciation of the midlands of Ireland are tested against an interpretation of a suite of deglacial sediments covering an area of 600 km 2 in the east central midland area. Interpretation of the sediments is based on geomorphological mapping, lithostratigraphic characterization of exposures and geotechnical data supported by electrical resistivity tomography (ERT) and ground penetrating radar (GPR). GPR depicted small-scale sedimentological and deformational structures within low-conductivity soft sediments, such as cross-bedding, planar bedding, channel-like features and faulting planes, and revealed the internal architecture of eskers, glaciodeltas, subaqueous fans and raised bogs. ERT data permitted the detection of depth to bedrock and the lithological characterization of unconsolidated sediments. The ten sites presented were surveyed by traditional mapping methods and/or geophysical techniques. This allowed the construction of a local model of the deglaciation of the area which recognized five main stages. An ice sheet covering most of Ireland withdrew as a single body as far as the midlands. At this stage, two main directions of ice retreat are identified from the spatial distribution of meltwater/overflow channels, esker and morainic ridges, and ice-marginal glaciolacustrine deposits. A pattern of deglacial sedimentation into an expanding ice-marginal glacial lake is depicted. The glacial lake was dammed to the west by two ice dome fronts, one decaying to the north-west and another to the south-west, and by the Shannon Basin watershed to the east. Glacial lake outlets identified along the watershed and the altitude of the topset/foreset interface zone depicted in glaciodeltaic deposits allowed the identification of three lake water levels. The highest level is at 87–89 m Ordnance Datum (OD), the second lake level at 84 m OD and the third at 78 m OD. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Simultaneous changes in the representation of wetland and dry land taxa are a common feature of mid and late Holocene pollen diagrams from the coastal wetlands of North-West Europe. Distinguishing both the areas affected and between natural and anthropogenic causes can be problematic. High temporal resolution, improved taxonomic procedures and multivariate statistics have been applied to two Thames estuary sites, along with simulation models, to resolve these issues. Large Poaceae pollen grains appear to be derived from wild grasses rather than cereals, while modelling indicates that even extensive clearance in dry land areas produces relatively minor changes in pollen assemblages where fen carr is the in situ vegetation. It is concluded that rapid/abrupt simultaneous pollen stratigraphic events in coastal wetlands are likely to have been caused by wetland vegetation changes alone. Simultaneous events, dating from c . 2150–1300 cal a BC, can be distinguished at 12 Thames estuary pollen sites. During this interval inter-tidal environments expanded creating areas attractive to human populations for pasturage. This exploitation is likely to have led to further changes in wetland vegetation and increased clearance activity on adjacent dry land areas. In such circumstances disentangling the processes causing vegetation change is challenging, although considerably aided by the techniques adopted in this paper. Copyright © 2012 John Wiley & Sons, Ltd.

Description: On 12 September AD 1717, a rock volume larger than 10 million m 3 collapsed onto the Triolet Glacier, mobilized a mass composed of ice and sediment and travelled more than 7 km downvalley in the upper Ferret Valley, Mont Blanc Massif (Italy). This rock avalanche destroyed two small settlements, causing seven casualties and loss of livestock. No detailed maps were made at the time. Later investigators attributed accumulations of granitic boulders and irregular ridges on the upper valley floor to either glacial deposition, or the AD 1717 rock avalanche, or a complex mixture of glacial deposition, earlier rock avalanche and AD 1717 rock avalanche origin. In this study, we present cosmogenic 10 Be exposure ages from nine boulders in the extensive chaotic boulder deposit with irregular ridges, two from Holocene glacier-free areas, and one from a Little Ice Age moraine. Exposure ages between 330 ± 23 and 483 ± 123 a from eight of nine boulders from the chaotic deposit indicate that at least seven were deposited by the AD 1717 rock avalanche. The other three boulders yielded 10 Be exposure ages of 10 900 ± 400, 9700 ± 400 and 244 ± 97 a, respectively. Our results are in good agreement with the existing chronology from dendrochronology and lichenometry, and radiocarbon analysis of wood samples, but not with older 14 C ages from a peat bog in the upper part of the valley. Based on the new age control, the rock avalanche deposits cover the whole bottom of the upper Ferret valley. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Radiocarbon-dated sediment cores from six lakes in the Ahklun Mountains, south-western Alaska, were used to interpolate the ages of late Quaternary tephra beds ranging in age from 25.4 to 0.4 ka. The lakes are located downwind of the Aleutian Arc and Alaska Peninsula volcanoes in the northern Bristol Bay area between 159° and 161°W at around 60°N. Sedimentation-rate age models for each lake were based on a published spline-fit procedure that uses Monte Carlo simulation to determine age model uncertainty. In all, 62 14 C ages were used to construct the six age models, including 23 ages presented here for the first time. The age model from Lone Spruce Pond is based on 18 ages, and is currently the best-resolved Holocene age model available from the region, with an average 2σ age uncertainty of about ± 109 years over the past 14.5 ka. The sedimentary sequence from Lone Spruce Pond contains seven tephra beds, more than previously found in any other lake in the area. Of the 26 radiocarbon-dated tephra beds at the six lakes and from a soil pit, seven are correlated between two or more sites based on their ages. The major-element geochemistry of glass shards from most of these tephra beds supports the age-based correlations. The remaining tephra beds appear to be present at only one site based on their unique geochemistry or age. The 5.8 ka tephra is similar to the widespread Aniakchak tephra [3.7 ± 0.2 (1σ) ka], but can be distinguished conclusively based on its trace-element geochemistry. The 3.1 and 0.4 ka tephras have glass major- and trace-element geochemical compositions indistinguishable from prominent Aniakchak tephra, and might represent redeposited beds. Only two tephra beds are found in all lakes: the Aniakchak tephra (3.7 ± 0.2 ka) and Tephra B (6.1 ± 0.3 ka). The tephra beds can be used as chronostratigraphic markers for other sedimentary sequences in the region, including cores from Cascade and Sunday lakes, which were previously undated and were analyzed in this study to correlate with the new regional tephrostratigraphy. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Study of the glacial deposits and lacustrine sediments of Campo Felice (Apennines, central Italy) has enabled the glacial phases of the last 40 ka to be dated more precisely, and has demonstrated that the maximum glacial advance did not occur in correspondence with the last global glacial maximum and with the coldest and most arid phase suggested by the pollen, but in a period dated between about 33 and 27 ka, characterized by a less extreme climate. Furthermore, a glacial expansion took place also in the period prior to 35 ka. Correlation with the Alpine glacial variations has shown that the Apennine last glacial maximum occurred before that of the southern slope of the Alps. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Tropical cyclones (TC) are recognized to modify the thermal structure of the upper ocean through the process of vertical mixing. Assessing the role this mixing plays in the overall stratification of the upper ocean is difficult, due to the relatively short and incomplete instrumental record. Proxy records for both TC landfalls and oceanographic stratification are preserved within the geological record and provide insight for how past changes in TC-induced mixing have potentially affected water column structure prior to the instrumental record. Here we provide the first comparison between previously published paleo-reconstructions of vertical ocean density and tropical cyclone activity from the western North Atlantic. A prominent lull in TC activity has been observed prior to approximately 1700 CE that extends back several centuries. This interval of low TC activity is shown to be concurrent with the timing of increased ocean stratification near Great Bahama Bank, potentially due in part to reduced TC-induced mixing. To test whether this relationship is feasible, we present numerical results from a coarse-resolution ocean general circulation model experiment isolating the effect of TC surface wind forcing on the upper ocean. An anomaly of roughly 0.12 kg m −3 in vertical stratification occurs above and below the mixed layer for model runs with and without TC mixing. This anomaly is roughly 25% of the entire paleo-density signal observed just prior to 1700 CE. These results suggest that TC mixing alone cannot completely explain the density anomaly observed prior to 1700 CE, but support TC variability as an important contributor to enhancing oceanic stratification during this interval. Copyright © 2011 John Wiley & Sons, Ltd.

Description: High-resolution pollen and geochemical analyses conducted on a sediment profile from a small lake in County Sligo, Ireland, revealed that human development during the Neolithic was influenced by pronounced climatic oscillations. The primeval woodland around the lake experienced a considerable transformation coinciding with the elm decline at 3810 BC. The subsequent increase in summer temperatures and decrease in precipitation favoured wheat cultivation in the lake's catchment area, which was practised for approximately 140 years. A shift towards pastoral farming took place with the establishment of exceptionally dry conditions between 3650 and 3560 BC, when lake level and influx of allochthonous material were notably low. The onset of cool and wet conditions at the transition from the Early to Middle Neolithic possibly caused the initial decline of human activity in the area. Periods of particularly high precipitation during the Middle and early Late Neolithic contributed to the abandonment of the area by the first farmers. Comparison of the proxy record from the study site with other palynological and archaeological records from Ireland suggests that climatic variability on the decadal to centennial scale represented a primary control on the nature and duration of farming practices during the Neolithic. Copyright © 2012 John Wiley & Sons, Ltd.

Description: A cryptotephra layer from the eruption of Hekla in 1947 has recently been discovered in Irish peatlands. This tephra layer represents the most recent deposition of volcanic ash in the UK prior to the eruption of Eyjafjallajökull in 2010. Here we examine the concentration and geochemistry of the Hekla 1947 tephra in 14 peat profiles from across Northern Ireland. Electron probe microanalysis of individual tephra shards ( n  = 91) reveals that the tephra is of dacitic–andesitic geochemistry and is highly similar to the Hekla 1510 tephra, although spheroidal carbonaceous particle profiles can be used for successful discrimination of the two layers. The highest concentrations of Hekla 1947 are found in western sites, probably reflecting the pathway of the ash fall event due to the prevailing wind direction. Comparable tephra concentrations from two cores (1 km apart) from a single bog and from nearby sites may suggest that tephra shard concentrations in peat profiles reflect ash fallout densities across a specific region, rather than site-specific factors associated with peatlands. This paper firmly establishes Hekla 1947 as a useful chronostratigraphic marker for the twentieth century, although within a restricted zone. Copyright © 2012 John Wiley & Sons, Ltd.

Description: We analysed pollen from a sediment core from Fiddaun, a small Lateglacial lake basin in western Ireland. Results reflect the general Lateglacial vegetation development in Ireland, as reconstructed from other pollen records. The Fiddaun diagram shows a number of short-lived regressive vegetation phases during the Interstadial. The close similarity between two pollen records from the same region (Fiddaun and Lurga) indicates that these fluctuations probably reflect regional rather than local changes. Comparison with a previously published climate reconstruction, based on a chironomid-inferred mean July air temperature reconstruction, lithology, and oxygen and carbon isotopes of lake marl from the Fiddaun record, allowed us to establish the relationship between summer temperature and vegetation changes. Results reveal that two temporary regressive shifts in the pollen record correspond to cold oscillations, which have been correlated to Greenland Interstadial 1b and 1d. It seems that the first cold oscillation (GI-1d) had the most distinct effect on vegetation in Ireland. In contrast, it appears that the transition from Juniperus shrubland and Empetrum heath to grassland, which is estimated at ∼13.7 ka BP, was not caused by decreasing summer temperatures, as no substantial change is observed in the climate proxies. Copyright © 2012 John Wiley & Sons, Ltd.

Description: We investigated use of δ 13 C in bulk organic sediment to define the botanical origin of samples preserved in coastal sediment as a means to reconstruct relative sea level in New Jersey, USA. Modern transects at three sites demonstrated that low and high salt-marsh floral zones dominated by C 4 species ( Spartina alterniflora and Spartina patens ) were associated with sediment δ 13 C values between −18.9‰ and −15.8‰ and occurred from mean tide level (MTL) to mean higher high water (MHHW). Brackish transitional settings vegetated by Phragmites australis with Iva fructescens and Typha sp. (C 3 species) and freshwater upland samples (C 3 species) were characterized by bulk sediment δ 13 C values of −27.0‰ to −22.0‰ and existed above MHHW. Parallel transects at one site suggested that intra-site variability was not discernible. The utility of δ 13 C values for reconstructing relative sea level in New Jersey is limited by an inability to differentiate between brackish sediments related to sea level and freshwater upland samples. To facilitate this distinction in a 4.4 m core, we used a multi-proxy approach (δ 13 C values with presence or absence of agglutinated foraminifera) to recognize indicative meanings for four sample types. Sediment with δ 13 C values greater than −18.9‰ was derived from a vegetated salt-marsh and formed between MTL and MHHW. Sediment with δ 13 C values less than −22.0‰ and containing agglutinated foraminifera formed in a brackish transitional zone between MHHW and highest astronomical tide (HAT). This is the narrowest elevational range of the four sample types and most precise sea-level indicator. Sediment with δ 13 C values less than −22.0‰ and lacking foraminifera can only constrain the upper bound of former sea level. Samples with intermediate values (−22.0‰ to −18.9‰) formed between MTL and HAT. Using these indicative meanings and radiocarbon dates, we suggest that a transition from brackish to salt-marsh δ 13 C values recorded in the core took approximately 350 years (from 1800 to 1450 cal. a BP). Copyright © 2011 John Wiley & Sons, Ltd.

Description: Ocean Drilling Program Leg 155 Site 942 on the Amazon Fan is an ideal location for monitoring palaeoclimatic changes within a significant proportion of the Amazon Basin. We present n- alkane δ 13 C and taraxerol and laevoglucosan concentration records from this site covering the last 38 ka. The entire n -alkane δ 13 C record is constrained between −31‰ and −34‰, which is well within the isotopic range occupied by C 3 vegetation. The concentration and relative abundance of taraxerol, a mangrove indicator, varies by over an order of magnitude, but seems to have had no effect on the n -alkane δ 13 C record. The laevoglucosan concentrations are extremely low during the last glacial period, suggesting a relatively low occurrence of forest fires. Laevoglucosan concentrations are highest between 13.5 and 12.5 ka, suggesting an increased incidence of Amazon forest fires at the very end of the Younger Dryas. These records, combined with previously published pollen records from Site 932, reveal no evidence for massive incursions of grasslands into Amazonia during the last glacial period, despite evidence of reduced outflow of the Amazon River indicating more arid conditions. We therefore suggest that savannah encroachment, as proposed by the Pleistocene refuge hypothesis, can be refuted as an explanation for high species endemism within the Amazon Basin, and alternative explanations are required. Copyright © 2012 John Wiley & Sons, Ltd.

Description: In order to understand natural sea-level variability, and to enhance future predictions, accurate and precise estimates of Holocene tidal levels are required. Although the application of diatom-based transfer functions can yield such data, these work best when underpinned by local training sets. Urbanized estuaries offer little prospect of obtaining local training sets and, instead, the reliability of regional transfer functions has to be assessed. The performance of a published regional (UK) diatom-based tidal-level transfer function applied to fossil assemblages from two contrasting core sites in the Mersey Estuary, UK, is assessed using modern analogue techniques and sediment isotope data. We find that, although estimated tidal levels coincide with changes in organic matter source, the frequent lack of modern analogues mean that palaeotide estimates are without basis. This is likely a consequence of the site-specific nature of diatom assemblages in higher intertidal and supratidal areas in particular, where local factors are expected to exert a greater control on their ecology. This situation may be partly resolved by constructing and applying much larger regional training sets from multiple higher intertidal and supratidal sites (where intact). Otherwise the application of alternative techniques, such as regional foraminiferal tidal-level transfer functions, may be more appropriate. Copyright © 2011 John Wiley & Sons, Ltd.

Description: Alluvial and colluvial sediment deposition provide a vital record of environmental change during the Holocene. Firm chronological control on these archives is necessary to enable us to relate sediment dynamics to human activity and climate variability. In the Eastern Mediterranean, such relationships are hard to establish due to the lack of spatially well-distributed sediment archives with good chronological control. This scarcity is problematic with respect to regional-scale reconstructions of the temporal variation of sediment dynamics. Here, we present a radiocarbon database ( n  = 178) of geomorphological activity collected from multiple distinct sediment archives within the territory of Sagalassos in south-western Turkey. The data were grouped according to their sedimentary facies for analysis using cumulative probability distributions (CPDs) and sedimentation rate (SR) modelling. Two small-scale colluvial valleys, where chronological information was abundant, were investigated in more detail. Results show that sedimentation chronology differs between individual, nearby cores, as it depends strongly on the local geomorphic situation. A generalizing approach combining multiple core results yields more widely valid conclusions. High sedimentation rates coincided with the initial major anthropogenic disturbance of the landscape and decreased afterwards, probably due to hillslope soil depletion. CPD and SR analysis indicates that in general colluvial sedimentation rates did not change much from 2000 BC onwards. River floodplain sedimentation, in contrast, increased markedly during the first millennium BC and during recent times, and a significant time lag in enhanced sediment deposition between the upper and lower reaches of the river valleys was observed. Copyright © 2012 John Wiley & Sons, Ltd.

Description: We examined mammal occurrence and variability through the Late Pleistocene vertebrate fossil deposit of Grant Hall in Victoria Fossil Cave, Naracoorte, South Australia. To determine long-term patterns of change, we compared the composition and relative abundance trends of the assemblage with a nearby Middle Pleistocene deposit in Cathedral Cave. Total species richness did not change through the Grant Hall sequence, dated from 93 ± 8 to 70 ± 5 ka. However, species relative abundances varied between ecologically divergent species, and in some cases between species that demonstrate similar environmental preferences. For some species this variation is comparable to that recorded in Cathedral Cave. Of those showing similar trends between the two deposits, the forest inhabitant, Pseudomys fumeus , recorded an 8.6% decline through Grant Hall, coincident with a 9.7% increase in the dry heath/mallee dweller Pseudomys apodemoides . These patterns indicate that climatic transition from relatively warm, moist to cooler, drier conditions impacted some species in similar ways through climatic cycles of the past. However, the majority of the fauna demonstrated complex responses that are individual and variable through time. Statistical tests of species trends from the Grant Hall assemblage caution that large fossil samples are required to validate patterns observed. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Along the West Greenland continental margin adjoining Baffin Bay, bathymetric data show a series of large submarine fans located at the mouths of cross-shelf troughs. One of these fans, termed here ‘Uummannaq Fan’, is a trough-mouth fan built largely by debris delivered from a fast-flowing outlet of the Greenland Ice Sheet during past glacial maxima. Cores from this fan provide the first information on glacimarine sedimentary facies within a major West Greenland trough-mouth fan and on the nature of Late Weichselian–Holocene glacigenic sediment delivery to this region of the Baffin Bay margin. Glacigenic debris flows deposited on the upper slope and extending to at least 1800 m water depth in front of the trough-mouth are related to the remobilization of subglacial debris that was delivered onto the upper slope at times when an ice stream was positioned at the shelf edge. In contrast, sedimentary facies from the northern sector of the fan are characterized by hemipelagic and ice-rafted sediments and turbidites; glacigenic debris flows are notably absent in cores from this region. Quantitative X-ray diffraction studies of the 〈2-mm sediment fraction indicate that the bulk of the sediment in the fan is derived from Uummannaq Trough but there are distinct intervals when sediment from northern Baffin Bay sources dominates, especially on the northern limit of the fan. These data demonstrate considerable variation in the nature of sediment delivery across the Uummannaq Fan when the Greenland Ice Sheet was at the shelf edge. They highlight the variability of glacimarine depositional processes operating on trough-mouth fans on high-latitude continental margins during the last glacial maximum and indicate that glacigenic debris flows are just one of a number of mechanisms by which such large depocentres form. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Large asteroid impacts are rare, and those into the deep ocean are rarer still. The Eltanin asteroid impact around 2.51 ± 0.07 Ma occurred at a time of great climatic and geological change associated with the Pliocene–Pleistocene boundary. Numerical models of the event indicate that a megatsunami was generated, although there is debate concerning its magnitude and the region-wide extent of its influence. We summarise the existing evidence for possible Eltanin megatsunami deposits in Antarctica, Chile and New Zealand, while also examining other potential sites from several locations, mainly around the South Pacific region. In reviewing these data we note that these events were unfolding at the same time as those associated with the Pliocene–Pleistocene boundary and, as such, most of the geological evidence from that time has a climatic interpretation. The potential climatic and geological ramifications of the Eltanin asteroid impact, however, have failed to be considered by most researchers studying this time period. Although we are not advocating that all geological activity at that time is connected with the Eltanin asteroid impact, it raises interesting questions about the role potentially played by such catastrophic events in contributing to or even triggering epochal transitions. Copyright © 2012 John Wiley & Sons, Ltd.

Description: High-resolution pollen, macrofossil and charcoal data, combined with accelerator mass spectrometry 14 C dating and multivariate analysis, were used to reconstruct Holocene vegetation and fire dynamics at Urio Quattrocchi, a small lake in the supra-mediterranean belt in the Nebrodi Mountains of Sicily (Italy). The data suggest that after 10 000 cal a BP increasing moisture availability supported closed forests with deciduous ( Quercus cerris , Fagus sylvatica and Fraxinus spp.) and evergreen ( Quercus ilex ) species. Species-rich closed forest persisted until 6850 cal a BP, when Neolithic activities caused a forest decline and affected plant diversity. Secondary forest with abundant Ilex aquifolium recovered between 6650 and 6000 cal a BP, indicating moist conditions. From 5000 cal a BP, agriculture and pastoralism led to the currently fragmented landscape with sparse deciduous forests ( Quercus cerris ). The study suggests that evergreen broadleaved species were more important at elevations above 1000 m a.s.l. before ca. 5000 cal a BP than subsequently, which might reflect less human impact or warmer-than-today climatic conditions between 10 000 and 5000 cal a BP. Despite land use since Neolithic times, deciduous supra-mediterranean forests were never completely displaced from the Nebrodi Mountains, because of favourable moist conditions that persisted throughout the Holocene. Reconstructed vegetation dynamics document the absence of any pronounced mid- or late-Holocene ‘aridification’ trend at the site, an issue which is controversially debated in Italy and the Mediterranean region. Copyright © 2012 John Wiley & Sons, Ltd.

Description: This discussion paper, by a Working Group of INTIMATE (Integration of ice-core, marine and terrestrial records) and the Subcommision on Quaternary Stratigraphy (SQS) of the International Commission on Stratigraphy (ICS), considers the prospects for a formal subdivision of the Holocene Series/Epoch. Although previous attempts to subdivide the Holocene have proved inconclusive, recent developments in Quaternary stratigraphy, notably the definition of the Pleistocene–Holocene boundary and the emergence of formal subdivisions of the Pleistocene Series/Epoch, mean that it may be timely to revisit this matter. The Quaternary literature reveals a widespread but variable informal usage of a tripartite division of the Holocene (‘early’, ‘middle’ or ‘mid’, and ‘late’), and we argue that this de facto subdivision should now be formalized to ensure consistency in stratigraphic terminology. We propose an Early–Middle Holocene Boundary at 8200 a BP and a Middle–Late Holocene Boundary at 4200 a BP, each of which is linked to a Global Stratotype Section and Point (GSSP). Should the proposal find a broad measure of support from the Quaternary community, a submission will be made to the International Union of Geological Sciences (IUGS), via the SQS and the ICS, for formal ratification of this subdivision of the Holocene Series/Epoch. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The sedimentology and stratigraphy of a multi-phase glaciation sequence dating to Marine Isotope Stage 6 in the Rakaia Valley, South Island, New Zealand, is presented. This outcrop presents an example of the depositional signature of an end member of temperate valley glaciation, where voluminous sediment supply in a tectonically active setting combines with high annual temperatures and low seasonality to generate significant year-round glacifluvial activity. Such glacial systems produce geological–climatic units that are dominated by thick sequences of aggradational gravels and proglacial lake sediments trapped behind outwash heads during deglaciation. At Bayfields Cliff, outwash sequences record an oscillating glacier margin marked by a sequence of glacier-fed, Gilbert-type deltas. The deltas are cut by numerous small-scale, syndepositional, normal faults indicating both loss of glacier support and melt-out of buried ice. A larger-scale thrust fault system reflects late-stage ice overrun. Braid plain gravels and chaotic disturbed glacial lake sediments are also recorded. A notable feature of these systems is the virtual absence of till in an environment with much other evidence for proximal ice. Cumulatively we regard these sediment–landform associations as diagnostic of debris-laden, perhumid, temperate valley glacier systems. Copyright © 2012 John Wiley & Sons, Ltd.

Description: In situ cosmogenic 14 C ( in situ 14 C) analysis from quartz-bearing rocks is a novel isotopic tool useful for quantifying recent surface exposure histories (up to ∼25 ka). It is particularly powerful when combined with longer-lived cosmogenic isotopes such as 10 Be. Recent advances in the extraction of in situ 14 C from quartz now permit the routine application of this method. However, only a few experiments to calibrate the production rate of in situ 14 C in quartz have been published to date. Here, we present a new in situ 14 C production rate estimate derived from a well-dated debris flow deposit in the Southern Alps, New Zealand, previously used to calibrate 10 Be production rates. For example, based on a geomagnetic implementation of the Lal/Stone scaling scheme we derive a spallogenic production rate of 11.4 ± 0.9 atoms 14 C (g quartz) −1 a −1 and a 14 C/ 10 Be spallogenic production rate ratio of 3.0 ± 0.2. The results are comparable with production rates from previous calibrations in the northern hemisphere. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Prehistoric storm records are relatively scarce in most parts of the world. This article presents storm records derived from coral rubble-based geological archives of the Houtman Abrolhos Archipelago located off the west coast of Australia, where the southernmost coral reefs of the Indian Ocean are found. Winter storm swell from the circum-Antarctic ‘Brave Westerlies’, as well as tropical cyclone waves, have left numerous ridge systems on dozens of islands of the archipelago, all composed of coral rubble from adjacent reefs. At three islands, seven ridge systems were dated by three different methods: U-series (68 dates), radiocarbon (64 dates), electron spin resonance (7 dates); 139 radiometric dates span the last 5500 years of the Holocene. In contrast to the geomorphological interpretation, the age sequences show ‘inversions’, hiatuses and different ages for the same ridge, all pointing to complicated ridge formation processes. Time gaps, some exceeding 1000 years, are interpreted as phases of erosion and not as phases without storm activity. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The East Asian monsoon climate system involves interactions between land and ocean and is composed of summer and winter monsoons. Cooling of surface water by the East Asian winter monsoon (EAWM) promotes the formation of sea ice and deep water in the northern Japan Sea. Modern observations suggest close relationships between intensification of the EAWM and both sea ice formation and sea-surface temperature (SST) decrease in the northeastern Japan Sea. Records of ice-rafted debris (IRD) and alkenone-based SST in the northeastern Japan Sea are examined to clarify the temporal variability of the EAWM and its controlling factors. Close relationships with oxygen isotope records of Chinese stalagmites and Northern Hemisphere summer insolation are observed in the records of IRD occurrence and SST during Marine Isotope Stages (MIS) 3–5. The co-occurrence of maxima in the abundance of IRD and minima in SST in the northeastern Japan Sea indicates that the intensity of the EAWM was enhanced during periods of low summer insolation and high oxygen isotope ratios in Chinese stalagmites. Decoupling between the IRD and SST records during MIS 2 and MIS 6 might be the result of differences in surface water conditions caused by low sea levels and the resultant closure of the Tsushima Strait. During MIS 3 and 4, some small but clear maxima in IRD and minima in SST occurred at relatively low summer insolation periods. Some of these peaks co-occur with North Atlantic Heinrich events, suggesting a possible climate linkage between the North Atlantic and the Asian monsoon. The presence of finer fluctuations in the occurrence of IRD than in summer insolation suggests finer millennial–centurial timescale fluctuations in the intensity of the EAWM. Furthermore, some IRD peaks occurred during periods of high insolation, such as 39, 86, 103, 128, 145, and 153 ka. Some of these IRD peaks correlate with minima in reconstructed SST and maxima in oxygen isotope ratios of Chinese stalagmites. This result suggests that extremely cold winters occur even during periods of enhanced East Asian summer monsoon intensity, and indicates that solar insolation is not the only factor that controls variations in the intensity of the EAWM at millennial–centurial timescales. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The transition from the last glacial and beginning of Bølling–Allerød and Pre-Boreal periods in particular is marked by rapid increases in atmospheric methane (CH 4 ) concentrations. The CH 4 concentrations reached during these intervals, ∼650–750 ppb, is twice that at the last glacial maximum and is not exceeded until the onset of industrialization at the end of the Holocene. Periods of rapid sea-level rise as the Last Glacial Maximum ice sheets retreated and associated with ‘melt-water pulses’ appear to coincide with the onset of elevated concentrations of CH 4 , suggestive of a potential causative link. Here we identify and outline a mechanism involving the flooding of the continental shelves that were exposed and vegetated during the glacial sea-level low stand and that can help account for some of these observations. Specifically, we hypothesize that waterlogging (and later, flooding) of large tracts of forest and savanna in the Tropics and Subtropics during the deglacial transition and early Holocene would have resulted in rapid anaerobic decomposition of standing biomass and emission of methane to the atmosphere. This novel mechanism, akin to the consequences of filling new hydroelectric reservoirs, provides a mechanistic explanation for the apparent synchronicity between rate of sea-level rise and occurrence of elevated concentrations of ice core CH 4 . However, shelf flooding and the creation of transient wetlands are unlikely to explain more than ∼60 ppb of the increase in atmospheric CH 4 during the deglacial transition, requiring additional mechanisms to explain the bulk of the glacial to interglacial increase. Similarly, this mechanism has the potential also to play some role in the rapid changes in atmospheric methane associated with the Dansgaard–Oeschger cycles. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Process length variation of cysts of the dinoflagellate Protoceratium reticulatum (Claparède et Lachmann) Bütschli in surface sediments from the North Pacific was investigated. The average process length showed a significant inverse relation to annual seawater density: σ t annual  = −0.8674 × average process length + 1029.3 ( R 2  = 0.84), with a standard error of 0.78 kg m −3 . A sediment trap study from Effingham Inlet in British Columbia revealed the same relationship between average process length and local seawater density variations. In the Baltic–Skagerrak region, the average process length variation was related significantly to annual seawater density: σ t annual  = 3.5457 × average process length − 993.28 ( R 2  = 0.86), with a standard error of 3.09 kg m −3 . These calibrations cannot be reconciled, which accentuates the regional character of the calibrations. This can be related to variations in molecular data (small subunit, long subunit and internal transcribed spacer sequences), which show the presence of several genotypes and the occurrence of pseudo-cryptic speciation within this species. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Marine Isotope Stage (MIS) 11 palaeoclimate has so far been documented in marine and ice sheet isotopic records. However, excepting some lacustrine pollen records, very little is known about palaeoclimatic conditions in continental areas. This study uses geochemical records in calcareous tufa deposits from rivers as a basis for reconstructing temperate palaeoclimatic conditions. Tufa deposits are now proven to record high-quality palaeoclimatic information in recent to Holocene deposits. Work on older interglacial tufas is just starting and in this paper we present the first comprehensive results from a MIS 11 tufa. The tufa comes from the Seine Valley (La Celle, northern France). Geochemical data in the tufa calcite are interpreted to record primarily air temperature (δ 18 O) and humidity (δ 13 C and Mg/Ca and Sr/Ca). The combined data identify a warm and wet climatic optimum followed by two temperature decreases associated with oscillations in humidity. These marked climatic variations recorded through the La Celle profile are strongly coherent with the palaeoenvironmental reconstructions from malacological data. The abrupt climatic and environmental events recorded could be related to short-term degradation of vegetation cover in Europe, which is itself controlled by global palaeoclimatic events. Copyright © 2012 John Wiley & Sons, Ltd.

Description: A high-resolution diatom record from site MD05-2908 in the Southern Okinawa Trough, East China Sea, reveals pronounced multidecadal- to centennial-scale palaeoceanographic changes throughout the last millennium. Summer sea-surface salinity (SSS) was reconstructed using a weighted averaging partial least squares diatom-based training set. The reconstructed SSS shows slightly decreasing values during the period AD 905–1930 with considerable fluctuations superimposed on this general trend. Relatively high-salinity conditions during the interval AD 905–1450 probably suggest a low flood frequency in north-eastern Taiwan. Furthermore, the high SSS values are associated with a strong and stable influence of the Kuroshio Current on the Southern Okinawa Trough during the Medieval Climate Anomaly. The period AD 1450–1930 is characterized by three low-salinity intervals (AD 1450–1500, AD 1625–1725 and AD 1770–1880) separated by periods of relatively high salinity. The low SSS intervals indicate increased freshwater discharge into the Southern Okinawa Trough during the Little Ice Age, probably as a result of higher flood frequencies in north-eastern Taiwan. Spectral and wavelet analyses suggest that this pattern was linked to multidecadal variations in summer SSS, presumably associated with the Pacific Decadal Oscillation. Copyright © 2012 John Wiley & Sons, Ltd.

Description: This paper presents a detailed palaeoglaciological reconstruction of ice sheet dynamics in the Seno Skyring, Seno Otway and Strait of Magellan region of the former Patagonian Ice Sheet, with a particular focus on previously hypothesised zones of rapid ice flow and the evolution of proglacial lakes. Geomorphological mapping from a combination of satellite imagery and oblique and vertical aerial photographs reveals a variety of glacial landforms that are grouped into several discrete flow-sets and associated ice margin positions. The most distinct features are represented by flow-sets of highly elongate streamlined glacial lineations on both sides of the Strait of Magellan. Based on the shape and dimensions of the flow-sets and their abrupt lateral margins, a transverse and longitudinal variation in glacial lineation length and elongation ratio, and the reported presence of a potentially deformable bed and thrust moraines, the flow-sets are interpreted as zones of rapid ice flow within the Otway and Magellan lobes. We hypothesise that this provides evidence for contemporaneous surge-like advances within the lobes, which may explain the asymmetry in the lobate margin positions on either side of the strait. The mechanisms that initiated rapid flow are unclear, but are likely to have been influenced by internal factors such as a change in thermal/hydrological conditions at the bed. The topography of the region suggests ice-dammed lakes would have formed as the ice lobes retreated. The westernmost of the former lakes, Lake Skyring, is delimited by a series of palaeo-shorelines surrounding the present-day lake Laguna Blanca and we reconstruct lake evolution based on manipulation of a digital elevation model. The size and orientation of meltwater channels and a large outwash plain indicate that Lake Skyring drained eastwards towards the Strait of Magellan, probably quite rapidly. We conclude that the potential for quasi-independent surge-like behaviour within adjacent lobes raises the possibility that, during climate-driven ice expansion, some advances in this region may have been partly controlled by secondary internal feedback mechanisms. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The glacial isostatic adjustment (GIA) of the British Isles is complex due to the interplay between local and non-local signals. A number of recent studies have modelled the GIA response of the British Isles using relative sea-level data. This study extends these previous analyses by using output from a numerical glaciological model as input to a GIA model. This is a necessary step towards more realistic GIA models, and although there have been similar studies for the major late Pleistocene ice sheets, this is the first study to do so for the British Isles. We test three reconstructions, classed as ‘minimal’, ‘median’ and ‘maximal’ in terms of their volume at maximum extent, and find it is possible to obtain good data–model fits. The minimal reconstruction is clearly preferred by the sea-level data. The ice reconstructions tested were not constrained by geomorphological information of past ice extent (lateral and vertical). As a consequence, the reconstructions extend further than much of this information suggests, particularly in terms of ice thickness. It is notable, however, that the reconstructions produce good fits to many sea-level data from central, mountainous regions (e.g. Scottish highlands), which lends support to the suggestion that trimlines, often used as an constraint on the palaeo ice surface location, are in fact features formed at the transition from warm- to cold-based ice and so mark a minimum constraint on the ice surface altitude. Based on data–model misfits, suggestions are made for improving the ice model reconstructions. However, in many locations, the cause of the misfit could be due to non-local, predominantly Fennoscandian ice and so interpretation is not straightforward. As a result, we suggest that future analyses of this type consider models and observations for both Fennoscandia and the British Isles. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The sedimentary records of Nulhegan Pond and Beecher Pond in the Nulhegan Basin of north-eastern Vermont were analyzed to yield a history of environmental change since the latest Pleistocene. Shoreline landforms indicate that part of the Nulhegan Basin was inundated by Glacial Lake Nulhegan (GLN), which was impounded behind a dam of glacial sediment. Outwash derived from stagnant ice forms the bottom 176 cm of the Nulhegan Pond core. Fine-grained inorganic sediment deposited between 13.4 and 12.2k cal a BP is interpreted as a deep-water facies representing GLN, while coarser sediment from 12.2 to 11.8k cal a BP records draining of the glacial lake. Rapid, simultaneous increases in organic matter and biogenic silica signal the onset of productivity following the Younger Dryas. Beecher Pond formed c . 11.3k cal a BP through surface collapse over a buried ice block; buried stagnant ice may have persisted in the vicinity of the pond into the early Holocene. From 8.9 to 5.5k cal a BP, sediment in both lakes became coarser and richer in aquatic organic matter, suggesting a low-water phase in which previously deposited lacustrine sediments were reworked and the littoral zone shifted basinward. Low water levels at this time are consistent with other records from Maine and southern Quebec, but contrary to records from ∼325 km to the south. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The peatlands of northern Scotland (one of the largest and most intact areas of blanket bog in the world) contain a rare widespread horizon of subfossil pine in stratigraphic context. Eighteen bog pine from three new sites are incorporated into a mean Neolithic pine chronology now composed of subfossil pine from 12 sites, which is tree-ring-dated against Irish bog pine chronologies to span 3198–2757 BC. Germination and peaks of radial growth infer drier conditions between 3199 and 3130 BC. Dying-off phases and depression of growth reflect a change to wetter conditions between 3023 and 3002 BC and a terminal decline of pine between 2809 and 2782 BC. The close synchronization of germination/die-off phases and major ring-width variations between sites across this region indicates that the environmental changes are probably triggered by climate change. Twenty-four bog pine samples remain unmatched. Future multi-discipline research into this important example of climatic change at the Neolithic/Bronze Age transition is recommended. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The late glacial and the transition towards the Holocene marked a period of significant environmental change at a global scale. In western Central Mexico, few records span beyond the Holocene, and little is known about Pleistocene climatic and environmental variability. Here we report on the pollen record of a composite sequence made of three cores that cover the last 50 ka (thousands of calibrated radiocarbon years before present) in the Zacapu Basin, western Central Mexico (∼1970 m asl). The conjunction of modern pollen rain from the area with the composite fossil pollen sequence from cores Cantabria, Cantabria 1 and CEMCA Point-1 provided a detailed history of the vegetation of the area. Recognition of modern environmental patterns through individual modern pollen taxa proved difficult, but multivariate analysis separated different vegetation types. No-modern-analog communities relative to the modern vegetation cover of the area were evident, especially during periods of drought. Apparently, summer precipitation was significant before 40 ka and after the deglaciation. However, this moisture source declined from ∼40 to 10 ka because tradewinds from the Gulf of Mexico were blocked by the eastern mountains of Central Mexico as a result of lower temperatures. By contrast, westerly and northerly winds were enhanced by maximum ice cover from ∼19 to 17 ka, providing abundant winter precipitation and therefore preventing extreme drought in the area. Copyright © 2012 John Wiley & Sons, Ltd.

Description: A peat deposit from the East European Russian Arctic, spanning nearly 10 000 years, was investigated to study soil organic matter degradation using analyses of bulk elemental and stable isotopic compositions and plant macrofossil remains. The peat accumulated initially in a wet fen that was transformed into a peat plateau bog following aggradation of permafrost in the late Holocene (∼2500 cal a BP). Total organic carbon and total nitrogen (N) concentrations are higher in the fen peat than in the moss-dominated bog peat layers. Layers in the sequence that have lower concentrations of total hydrogen (H) are associated with degraded vascular plant residues. C/N and H/C atomic ratios indicate better preservation of organic matter in peat material dominated by bryophytes as opposed to vascular plants. The presence of permafrost in the peat plateau stage and water-saturated conditions at the bottom of the fen stage appear to lead to better preservation of organic plant material. δ 15 N values suggest N isotopic fractionation was driven primarily by microbial decomposition whereas differences in δ 13 C values appear to reflect mainly changes in plant assemblages. Positive shifts in both δ 15 N and δ 13 C values coincide with a local change to drier conditions as a result of the onset of permafrost and frost heave of the peat surface. This pattern suggests that permafrost aggradation not only resulted in changes in vegetation but also aerated the underlying fen peat, which enhanced microbial denitrification, causing the observed 15 N-enrichment. Copyright © 2012 John Wiley & Sons, Ltd.

Description: On the basis of sedimentological analysis of two cores taken at Chatillon, Lake Le Bourget (northern French Pre-Alps), and well dated by radiocarbon dates in addition to tree ring dates obtained from an archaeological layer, this paper presents a high-resolution lake-level record for the period 4500–3500 cal. a BP. The collected data provide evidence of a complex palaeohydrological (climatic) oscillation spanning the ca. 4300–3850 cal. BP time interval, with major lake-level maxima at ca. 4200 and 4050–3850 cal. a BP separated by a lowering episode around 4100 cal. a BP. The lake-level highstands observed at Chatillon between 4300 and 3850 cal. BP appear to be synchronous with (i) a major flooding period recorded in deep cores from the large lakes Le Bourget and Bodensee, and (ii) glacier advance and tree line decline in the Alps. Such wetter and cooler climatic conditions in west-central Europe around 4000 cal. a BP may have been a nonlinear response to decrease and seasonal changes in insolation. They may also provide a possible explanation for the general abandonment of prehistoric lake dwellings north of the Alps between 4360 and 3750 cal. a BP. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Through a multidisciplinary approach based on novel micropaleontological and geochemical analyses, the main paleoceanographic and paleoclimate changes that have influenced the surface- and deep-water circulation in the SW Pacific Ocean (Chatham Rise, eastern New Zealand) during the last million years are reconstructed. This region represents a key area for investigating the climate evolution during the Pleistocene because here the largely wind-driven Antarctic Circumpolar Current interacts with the west Pacific Ocean circulation via the Deep Western Boundary Current, the major source of deep water for the whole Pacific Ocean. To understand coupling or decoupling events between sea surface and bottom waters, a continuous marine sedimentary succession since 1.1 Ma, recovered by the IMAGES (International Marine Past Global Change Study) cruise in the SW Pacific Ocean (Core MD97-2114), has been investigated based on calcareous planktonic and benthic microfossil content and C and O isotope record performed on planktonic and benthic foraminiferal tests. Results show the occurrence of long- and short-term patterns of climate and ocean circulation in the last million years as the result of the interplay of ice-sheet dynamics, surface tropical versus polar water inflow, and trophic status of the surface water. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Dendrochronological analysis was applied to subfossil remains of Scots pine ( Pinus sylvestris L.) buried in a South Swedish peat deposit. In combination with peat stratigraphy, this approach was explored for its potential to provide information on the local hydrological and depositional history at the site, forming the basis for a regional palaeohydrological analysis. A 726-year ring-width chronology was developed and assigned an absolute age of 7233–6508 cal a BP (5284–4559 BC) through cross-dating with German bog-pine chronologies, whereas two short additional records of older ages were radiocarbon dated. Registration of growth positions of individual trees allowed assessment of the spatial dynamics of the pine population in response to hydrological changes and peatland ontogeny. Annually resolved growth variability patterns in the pine population reveal several establishment and degeneration phases, probably reflecting fluctuations in bog-surface wetness. A major establishment phase at 7200–6900 cal a BP reflects the onset of a period of lowered groundwater level, also indicated by increased peat humification, and a development consistent with regional temperature and lake level reconstructions revealed from other proxies. This study demonstrates that subfossil bog-pine populations may provide annually to decadally resolved reconstructions of local groundwater variability, which are highly relevant in a long-term palaeoclimatic context. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Here we present Holocene organic carbon, nitrogen, sulphur, carbon isotope ratio and macrofossil data from a small freshwater lake near Sisimiut in south-west Greenland. The lake was formed c. 11 cal ka BP following retreat of the ice sheet margin and is located above the marine limit in this area. The elemental and isotope data suggest a complex deglaciation history of interactions between the lake and its catchment, reflecting glacial retreat and post-glacial hydrological flushing probably due to periodic melting of local remnant glacial ice and firn areas between 11 and 8.5 cal ka BP. After 8.5 cal ka BP, soil development and associated vegetation processes began to exert a greater control on terrestrial–aquatic carbon cycling. By 5.5 cal ka BP, in the early Neoglacial cooling, the sediment record indicates a change in catchment–lake interactions with consistent δ 13 C while C/N exhibits greater variability. The period after 5.5 cal ka BP is also characterized by higher organic C accumulation in the lake. These changes (total organic carbon, C/N, δ 13 C) are most likely the result of increasing contribution (and burial) of terrestrial organic matter as a result of enhanced soil instability, as indicated by an increase in Cenococcum remains, but also Sphagnum and Empetrum . The impact of glacial retreat and relatively subdued mid- to late Holocene climate variation at the coast is in marked contrast to the greater environmental variability seen in inland lakes closer to the present-day ice sheet margin. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Few terrestrial Holocene climate records exist from south-eastern Europe despite its important geographical position as a transitional climatic zone between the Mediterranean and mainland continental Europe. Here we present new petrographic and stable isotope data for two Holocene speleothems from Modrič Cave, Croatia (44°15′N, 15°32′E), a coastal Adriatic site (120 m inland). Modern meteorological and cave conditions have been monitored for 2 years to understand the links between climate variability and stable isotope time-series records in speleothems. Typical of a Mediterranean-type climate, a negative water balance exists between April and September, so that recharge of the aquifer is restricted to the winter months. The weighted mean δ 18 O of the rainfall is −5.96‰ (2σ = 2.83), and the weighted mean D/H rainfall value is −36.83‰ (2σ = 19.95), slightly above the Global Meteoric Water Line, but well below the Mediterranean Meteoric Water Line. Modern calcite from the tops of each stalagmite exhibits δ 18 O values that are close to isotopic equilibrium with their respective drip water values. Unfortunately, the relatively young ages and low uranium contents (ca. 50 p.p.b.) of both stalagmites hamper the use of U-series dating. Radiocarbon dates have been used instead to constrain their chronology using a dead carbon correction. Apart from some Isotope Stage 3 material (ca. 55 ka), both stalagmites were deposited during the late Holocene. Climatic conditions during the late Holocene are inferred to have been sufficiently wet to maintain stalagmite growth and any hiatuses appear to be relatively short lived. Inferred changes in the stalagmite diameters during deposition are linked to δ 13 C and δ 18 O variations, indicating alternating periods of drier and wetter conditions. Drier conditions are inferred for the late Roman Ages warm period and the mid-Medieval Warm Period. Wetter conditions are associated with the Little Ice Age. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Palaeoflood slackwater deposits (SWDs), are the natural record of overbank flooding and are often found within aeolian loess-soil profiles along the river valleys of the middle Yellow River basin. These pedo-stratigraphic sequences are studied using a multi-disciplinarily approach to reconstruct Holocene hydro-climatic variations. Our field investigations along the lower Jinghe River valley have identified palaeoflood SWDs at several sites along the riverbanks based on sedimentological criteria. Analytical results, including magnetic susceptibility, particle-size distribution and concentrations of chemical elements, indicate that these well-sorted palaeoflood SWD beds were deposited from the suspended sediment load in floodwaters. We identify two episodes of extraordinary palaeoflood events along the Jinghe River valley. These hydro-climatic events were dated to 4200–4000 and 3200–2800 a BP, by using the optically stimulated luminescence method in combination with archaeological dating of retrieved anthropogenic remains, and with pedo-stratigraphic correlations with the previously studied Holocene pedo-stratigraphy in the Jinghe River drainage basin. The flooding events are therefore considered to be a regional expression of known climatic events in the northern hemisphere and demonstrate Holocene climate was far from stable. This study provides important data in understanding the interactions between regional hydro-climatic systems and global change in semi-arid and sub-humid regions. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Pollen accumulation rates (PARs) provide a potential proxy for quantitative tree volume (m 3  ha −1 ) reconstruction with reliable absolute pollen productivity estimates (APPEs). We obtained APPEs for pine, spruce and birch at their range limits in northern Finland under two temperature periods (‘warm’ and ‘cold’) based on long-term pollen trap and tree volume records within a 14-km radius of each trap. APPEs (mean ± SE; × 10 8 grains m −3 a −1 ) tend to be higher for the ‘warm’ periods (pine 123.8 ± 24.4, birch 528.0 ± 398.4, spruce 434.3 ± 113.7) compared with the ‘cold’ periods (pine 95.5 ± 37.3, birch 317.3 ± 282.6, spruce 119.6 ± 37.6), although the difference is only significant for spruce. Using an independent temperature record and the APPEs obtained, we reconstruct a low-frequency record of pine volume changes over the last 1000 years at Palomaa mire, where a high-resolution record of Pinus PARs is available. Five phases are distinguished in the reconstruction: moderate pine volume, AD 1080–1170; high volume, AD 1170–1340; low volume, AD 1340–1630; very low volume, AD 1630–1810; and rising pine volume, AD 1810–1950. These phases do not coincide with periods of high or low June–July–August temperatures, and thus appear to reflect regional variations in tree volume, while high-frequency changes within each time-period block show variations in PARs in response to temperature. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Ocean Drilling Program Leg 155 Site 942 on the Amazon Fan is an ideal location for monitoring palaeoclimatic changes within a significant proportion of the Amazon Basin. We present n- alkane δ 13 C and taraxerol and laevoglucosan concentration records from this site covering the last 38 ka. The entire n -alkane δ 13 C record is constrained between −31‰ and −34‰, which is well within the isotopic range occupied by C 3 vegetation. The concentration and relative abundance of taraxerol, a mangrove indicator, varies by over an order of magnitude, but seems to have had no effect on the n -alkane δ 13 C record. The laevoglucosan concentrations are extremely low during the last glacial period, suggesting a relatively low occurrence of forest fires. Laevoglucosan concentrations are highest between 13.5 and 12.5 ka, suggesting an increased incidence of Amazon forest fires at the very end of the Younger Dryas. These records, combined with previously published pollen records from Site 932, reveal no evidence for massive incursions of grasslands into Amazonia during the last glacial period, despite evidence of reduced outflow of the Amazon River indicating more arid conditions. We therefore suggest that savannah encroachment, as proposed by the Pleistocene refuge hypothesis, can be refuted as an explanation for high species endemism within the Amazon Basin, and alternative explanations are required. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Simultaneous changes in the representation of wetland and dry land taxa are a common feature of mid and late Holocene pollen diagrams from the coastal wetlands of North-West Europe. Distinguishing both the areas affected and between natural and anthropogenic causes can be problematic. High temporal resolution, improved taxonomic procedures and multivariate statistics have been applied to two Thames estuary sites, along with simulation models, to resolve these issues. Large Poaceae pollen grains appear to be derived from wild grasses rather than cereals, while modelling indicates that even extensive clearance in dry land areas produces relatively minor changes in pollen assemblages where fen carr is the in situ vegetation. It is concluded that rapid/abrupt simultaneous pollen stratigraphic events in coastal wetlands are likely to have been caused by wetland vegetation changes alone. Simultaneous events, dating from c . 2150–1300 cal a BC, can be distinguished at 12 Thames estuary pollen sites. During this interval inter-tidal environments expanded creating areas attractive to human populations for pasturage. This exploitation is likely to have led to further changes in wetland vegetation and increased clearance activity on adjacent dry land areas. In such circumstances disentangling the processes causing vegetation change is challenging, although considerably aided by the techniques adopted in this paper. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Study of the glacial deposits and lacustrine sediments of Campo Felice (Apennines, central Italy) has enabled the glacial phases of the last 40 ka to be dated more precisely, and has demonstrated that the maximum glacial advance did not occur in correspondence with the last global glacial maximum and with the coldest and most arid phase suggested by the pollen, but in a period dated between about 33 and 27 ka, characterized by a less extreme climate. Furthermore, a glacial expansion took place also in the period prior to 35 ka. Correlation with the Alpine glacial variations has shown that the Apennine last glacial maximum occurred before that of the southern slope of the Alps. Copyright © 2012 John Wiley & Sons, Ltd.

Description: We examined mammal occurrence and variability through the Late Pleistocene vertebrate fossil deposit of Grant Hall in Victoria Fossil Cave, Naracoorte, South Australia. To determine long-term patterns of change, we compared the composition and relative abundance trends of the assemblage with a nearby Middle Pleistocene deposit in Cathedral Cave. Total species richness did not change through the Grant Hall sequence, dated from 93 ± 8 to 70 ± 5 ka. However, species relative abundances varied between ecologically divergent species, and in some cases between species that demonstrate similar environmental preferences. For some species this variation is comparable to that recorded in Cathedral Cave. Of those showing similar trends between the two deposits, the forest inhabitant, Pseudomys fumeus , recorded an 8.6% decline through Grant Hall, coincident with a 9.7% increase in the dry heath/mallee dweller Pseudomys apodemoides . These patterns indicate that climatic transition from relatively warm, moist to cooler, drier conditions impacted some species in similar ways through climatic cycles of the past. However, the majority of the fauna demonstrated complex responses that are individual and variable through time. Statistical tests of species trends from the Grant Hall assemblage caution that large fossil samples are required to validate patterns observed. Copyright © 2012 John Wiley & Sons, Ltd.

Description: On 12 September AD 1717, a rock volume larger than 10 million m 3 collapsed onto the Triolet Glacier, mobilized a mass composed of ice and sediment and travelled more than 7 km downvalley in the upper Ferret Valley, Mont Blanc Massif (Italy). This rock avalanche destroyed two small settlements, causing seven casualties and loss of livestock. No detailed maps were made at the time. Later investigators attributed accumulations of granitic boulders and irregular ridges on the upper valley floor to either glacial deposition, or the AD 1717 rock avalanche, or a complex mixture of glacial deposition, earlier rock avalanche and AD 1717 rock avalanche origin. In this study, we present cosmogenic 10 Be exposure ages from nine boulders in the extensive chaotic boulder deposit with irregular ridges, two from Holocene glacier-free areas, and one from a Little Ice Age moraine. Exposure ages between 330 ± 23 and 483 ± 123 a from eight of nine boulders from the chaotic deposit indicate that at least seven were deposited by the AD 1717 rock avalanche. The other three boulders yielded 10 Be exposure ages of 10 900 ± 400, 9700 ± 400 and 244 ± 97 a, respectively. Our results are in good agreement with the existing chronology from dendrochronology and lichenometry, and radiocarbon analysis of wood samples, but not with older 14 C ages from a peat bog in the upper part of the valley. Based on the new age control, the rock avalanche deposits cover the whole bottom of the upper Ferret valley. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Radiocarbon-dated sediment cores from six lakes in the Ahklun Mountains, south-western Alaska, were used to interpolate the ages of late Quaternary tephra beds ranging in age from 25.4 to 0.4 ka. The lakes are located downwind of the Aleutian Arc and Alaska Peninsula volcanoes in the northern Bristol Bay area between 159° and 161°W at around 60°N. Sedimentation-rate age models for each lake were based on a published spline-fit procedure that uses Monte Carlo simulation to determine age model uncertainty. In all, 62 14 C ages were used to construct the six age models, including 23 ages presented here for the first time. The age model from Lone Spruce Pond is based on 18 ages, and is currently the best-resolved Holocene age model available from the region, with an average 2σ age uncertainty of about ± 109 years over the past 14.5 ka. The sedimentary sequence from Lone Spruce Pond contains seven tephra beds, more than previously found in any other lake in the area. Of the 26 radiocarbon-dated tephra beds at the six lakes and from a soil pit, seven are correlated between two or more sites based on their ages. The major-element geochemistry of glass shards from most of these tephra beds supports the age-based correlations. The remaining tephra beds appear to be present at only one site based on their unique geochemistry or age. The 5.8 ka tephra is similar to the widespread Aniakchak tephra [3.7 ± 0.2 (1σ) ka], but can be distinguished conclusively based on its trace-element geochemistry. The 3.1 and 0.4 ka tephras have glass major- and trace-element geochemical compositions indistinguishable from prominent Aniakchak tephra, and might represent redeposited beds. Only two tephra beds are found in all lakes: the Aniakchak tephra (3.7 ± 0.2 ka) and Tephra B (6.1 ± 0.3 ka). The tephra beds can be used as chronostratigraphic markers for other sedimentary sequences in the region, including cores from Cascade and Sunday lakes, which were previously undated and were analyzed in this study to correlate with the new regional tephrostratigraphy. Copyright © 2012 John Wiley & Sons, Ltd.

Description: High-resolution pollen and geochemical analyses conducted on a sediment profile from a small lake in County Sligo, Ireland, revealed that human development during the Neolithic was influenced by pronounced climatic oscillations. The primeval woodland around the lake experienced a considerable transformation coinciding with the elm decline at 3810 BC. The subsequent increase in summer temperatures and decrease in precipitation favoured wheat cultivation in the lake's catchment area, which was practised for approximately 140 years. A shift towards pastoral farming took place with the establishment of exceptionally dry conditions between 3650 and 3560 BC, when lake level and influx of allochthonous material were notably low. The onset of cool and wet conditions at the transition from the Early to Middle Neolithic possibly caused the initial decline of human activity in the area. Periods of particularly high precipitation during the Middle and early Late Neolithic contributed to the abandonment of the area by the first farmers. Comparison of the proxy record from the study site with other palynological and archaeological records from Ireland suggests that climatic variability on the decadal to centennial scale represented a primary control on the nature and duration of farming practices during the Neolithic. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The Himalayas are a key location for understanding centennial- to millennial-scale variations in the Asian monsoon, yet few studies of the late Holocene have been conducted in this sensitive area. Direct evidence for shifts in monsoonal wind strength is often limited to marine proxy records, while terrestrial reconstructions (e.g. lake levels and spleothems) focus on precipitation. Here, we present the first evidence of terrestrial summer monsoon wind strength changes from Lake Rara, western Nepal, based on Mn/Ti ratios, a proxy for lake stratification. These data indicate a link between the Arabian Sea and the Himalayas, suggesting that centennial- to millennial-scale changes in wind strength occurred synchronously. Distinct similarity is also observed between Lake Rara and the southern part of China, which may support previous suggestions that the southern part of China is influenced by Indian summer monsoon. Copyright © 2012 John Wiley & Sons, Ltd.

Description: We analysed pollen from a sediment core from Fiddaun, a small Lateglacial lake basin in western Ireland. Results reflect the general Lateglacial vegetation development in Ireland, as reconstructed from other pollen records. The Fiddaun diagram shows a number of short-lived regressive vegetation phases during the Interstadial. The close similarity between two pollen records from the same region (Fiddaun and Lurga) indicates that these fluctuations probably reflect regional rather than local changes. Comparison with a previously published climate reconstruction, based on a chironomid-inferred mean July air temperature reconstruction, lithology, and oxygen and carbon isotopes of lake marl from the Fiddaun record, allowed us to establish the relationship between summer temperature and vegetation changes. Results reveal that two temporary regressive shifts in the pollen record correspond to cold oscillations, which have been correlated to Greenland Interstadial 1b and 1d. It seems that the first cold oscillation (GI-1d) had the most distinct effect on vegetation in Ireland. In contrast, it appears that the transition from Juniperus shrubland and Empetrum heath to grassland, which is estimated at ∼13.7 ka BP, was not caused by decreasing summer temperatures, as no substantial change is observed in the climate proxies. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Alluvial and colluvial sediment deposition provide a vital record of environmental change during the Holocene. Firm chronological control on these archives is necessary to enable us to relate sediment dynamics to human activity and climate variability. In the Eastern Mediterranean, such relationships are hard to establish due to the lack of spatially well-distributed sediment archives with good chronological control. This scarcity is problematic with respect to regional-scale reconstructions of the temporal variation of sediment dynamics. Here, we present a radiocarbon database ( n  = 178) of geomorphological activity collected from multiple distinct sediment archives within the territory of Sagalassos in south-western Turkey. The data were grouped according to their sedimentary facies for analysis using cumulative probability distributions (CPDs) and sedimentation rate (SR) modelling. Two small-scale colluvial valleys, where chronological information was abundant, were investigated in more detail. Results show that sedimentation chronology differs between individual, nearby cores, as it depends strongly on the local geomorphic situation. A generalizing approach combining multiple core results yields more widely valid conclusions. High sedimentation rates coincided with the initial major anthropogenic disturbance of the landscape and decreased afterwards, probably due to hillslope soil depletion. CPD and SR analysis indicates that in general colluvial sedimentation rates did not change much from 2000 BC onwards. River floodplain sedimentation, in contrast, increased markedly during the first millennium BC and during recent times, and a significant time lag in enhanced sediment deposition between the upper and lower reaches of the river valleys was observed. Copyright © 2012 John Wiley & Sons, Ltd.

Description: A detailed tephrochronological study was carried out on the deep-sea core collected from Site 963A in the Sicily Channel during ODP Leg 160. The chronology of the succession is provided by an age–depth model based on isotope stratigraphy and quantitative eco-biostratigraphy. Major, trace and rare earth element content was obtained on single glass grains through electron probe micro-analysis and laser ablation–inductively coupled plasma mass spectrometry techniques from six well-preserved tephra layers, characterized by a discrete thickness found along the succession. These deposits were correlated with the volcanic activity of Pantelleria and dated at 42.5, 127.5, 128.1, 129.1, 188.7 and 197.7 ka. This detailed chemical characterization of the studied deposits aims to provide a valuable reference database for scientists working on both proximal and distal products erupted at Pantelleria island during the Late Pleistocene. This study, moreover, offers the opportunity to better identify Pantelleria-related marker tephras within the tephrochronological framework of the central and eastern Mediterranean area. Copyright © 2012 John Wiley & Sons, Ltd.

Description: A cryptotephra layer from the eruption of Hekla in 1947 has recently been discovered in Irish peatlands. This tephra layer represents the most recent deposition of volcanic ash in the UK prior to the eruption of Eyjafjallajökull in 2010. Here we examine the concentration and geochemistry of the Hekla 1947 tephra in 14 peat profiles from across Northern Ireland. Electron probe microanalysis of individual tephra shards ( n  = 91) reveals that the tephra is of dacitic–andesitic geochemistry and is highly similar to the Hekla 1510 tephra, although spheroidal carbonaceous particle profiles can be used for successful discrimination of the two layers. The highest concentrations of Hekla 1947 are found in western sites, probably reflecting the pathway of the ash fall event due to the prevailing wind direction. Comparable tephra concentrations from two cores (1 km apart) from a single bog and from nearby sites may suggest that tephra shard concentrations in peat profiles reflect ash fallout densities across a specific region, rather than site-specific factors associated with peatlands. This paper firmly establishes Hekla 1947 as a useful chronostratigraphic marker for the twentieth century, although within a restricted zone. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Four Nordic temperature proxies based on tree growth at the northern timberline – ring-width from Sweden and Finland, maximum latewood density from Sweden, and height increment from Finland – were compared. Three indexing methods were used to enhance the low (centennial and above), medium (decadal-to-multidecadal) and high (decadal-to-interannual) frequencies. The proxies are shown to have a strong temperature signal (common variance) at the interannual-to-multidecadal scale, while the multidecadal-to-centennial trends are less coherent, perhaps reflecting intra-regional differences in growing conditions but more likely due to the more noisy regional curve standardization method used to retain the longest trends. Various methods of combining the four proxy series were explored and tested by comparison with four long temperature records from northern Fennoscandia. Only relatively high-frequency, spline-indexed series produced consistently positive verification statistics as a reconstruction model for summer temperature using all four proxies. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The Amazonian lowlands include large patches of open vegetation which contrast sharply with the rainforest, and the origin of these patches has been debated. This study focuses on a large area of open vegetation in northern Brazil, where δ 13 C and, in some instances, C/N analyses of the organic matter preserved in late Quaternary sediments were used to achieve floristic reconstructions over time. The main goal was to determine when the modern open vegetation started to develop in this area. The variability in δ 13 C data derived from nine cores ranges from −32.2 to −19.6‰, but with nearly 60% of data above −26.5‰. The most enriched values were detected only in ecotone and open vegetated areas. The development of open vegetation communities was asynchronous, varying between estimated ages of 6400 and 3000 cal a BP. This suggests that the origin of the studied patches of open vegetation might be linked to sedimentary dynamics of a late Quaternary megafan system. As sedimentation ended, this vegetation type became established over the megafan surface. In addition, the data presented here show that the presence of C 4 plants must be used carefully as a proxy to interpret dry paleoclimatic episodes in Amazonian areas. Copyright © 2012 John Wiley & Sons, Ltd.

Description: A combination of a dense reflection seismic grid and up to 50-m-long records from sediment cores and cone penetration tests was used to study the geometry and infill lithology of an E–W-trending buried tunnel valley in the south-eastern North Sea. In relation to previously known primarily N–S-trending tunnel valleys in this area, the geometry and infill of this 38-km-long and up to 3-km-wide valley is comparable, but its E–W orientation is exceptional. The vertical cross-section geometry may result from subglacial sediment erosion of advancing ice streams and secondary incision by large episodic meltwater discharges with high flow rates. The infill is composed of meltwater sands and reworked till remnants on the valley flanks that are overlain by late Elsterian rhythmic, laminated, lacustrine fine-grained sediments towards the centre of the valley. A depression in the valley centre is filled with sediments most likely from the Holsteinian transgression and a subsequent post-Holsteinian lacustrine quiet-water setting. The exceptional axis orientation of this tunnel valley points to a regional N–S-oriented ice front during the late Elsterian. Copyright © 2012 John Wiley & Sons, Ltd.

Description: We present a chronology of late Pleistocene deglaciation and Neoglaciation for two valleys in the north-central Brooks Range, Alaska, using cosmogenic 10 Be exposure dating. The two valleys show evidence of ice retreat from the northern range front before ∼16–15 ka, and into individual cirques by ∼14 ka. There is no evidence for a standstill or re-advance during the Lateglacial period, indicating that a glacier advance during the Younger Dryas, if any, was less extensive than during the Neoglaciation. The maximum glacier expansion during the Neoglacial is delimited by moraines in two cirques separated by about 200 km and dated to 4.6 ± 0.5 and 2.7 ± 0.2 cal ka BP. Both moraine ages agree with previously published lichen-inferred ages, and confirm that glaciers in the Brooks Range experienced multiple advances of similar magnitude throughout the late Holocene. The similar extent of glaciers during the middle Holocene and the Little Ice Age may imply that the effect of decreasing summer insolation was surpassed by increasing aridity to limit glacier growth as Neoglaciation progressed. Copyright © 2012 John Wiley & Sons, Ltd.

Description: This paper assesses variations in quantitative reconstructions of late Holocene relative sea-level (RSL) change arising from using modern diatom datasets from different spatial scales, applied to case studies from Alaska. We investigate the implications of model choice in transfer functions using local-, sub-regional- and regional-scale modern training sets, and produce recommendations on the creation and selection of modern datasets for reconstructing RSL change over Holocene timescales in tidal marsh environments comparable with those in Alaska. We show that regional modern training sets perform best in terms of providing fossil samples with good modern analogues, and in producing reconstructions that most closely match observations, where these are available. Local training sets are frequently insufficient to provide fossil samples with good modern analogues and may over-estimate the precision of RSL reconstructions. This is particularly apparent when reconstructing RSL change for periods beyond the last century. For reconstructing RSL change we recommend using regional modern training sets enhanced by local samples. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Proxy reconstructions of climatic parameters developed using transfer functions are central to the testing of many palaeoclimatic hypotheses on Holocene timescales. However, recent work shows that the mathematical models underpinning many existing transfer functions are susceptible to spatial autocorrelation, clustered training set design and the uneven sampling of environmental gradients. This may result in over-optimistic performance statistics or, in extreme cases, a lack of predictive power. A new testate amoeba-based transfer function is presented that fully incorporates the new recommended statistical tests to address these issues. Leave-one-out cross-validation, the most commonly applied method in recent studies to assess model performance, produced over-optimistic performance statistics for all models tested. However, the preferred model, developed using weighted averaging with tolerance downweighting, retained a predictive capacity equivalent to other published models even when less optimistic performance statistics were chosen. Application of the new statistical tests in the development of transfer functions provides a more thorough assessment of performance and greater confidence in reconstructions based on them. Only when the wider research community have sufficient confidence in transfer function-based proxy reconstructions will they be commonly used in data comparison and palaeoclimate modelling studies of broader scientific relevance. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Oxygen isotope variations in Chinese stalagmites have been widely interpreted as a record of the amount of East Asian summer monsoonal rainfall. This interpretation infers decreasing monsoonal rainfall from the mid-Holocene and large, dipolar rainfall oscillations within glaciations. However, the speleothem δ 18 O variations conflict with independent palaeoclimate proxies (cave δ 13 C, loess/palaeosol magnetic properties, δ 13 C alkanes), which indicate no systematic decline in rainfall from the mid-Holocene, and no glacial rainfall maxima. Using mass balance calculations (which incorporate seasonality effects in both δ 18 O concentration and amount of precipitation), we demonstrate that the cave δ 18 O variations cannot be accounted for by summer rainfall changes, or rainfall seasonality or winter cooling, but instead reflect changes in moisture source. A possible driver of the δ 18 O variations in Chinese stalagmites is precessional forcing of inter-hemispheric temperature gradients, and resultant shifts in the position and intensity of the subtropical pressure cells. Through such forcing, Indian monsoon-sourced δ 18 O may have dominated at times of high boreal summer insolation, and local Pacific-sourced moisture at low insolation. Suppression of summer monsoonal rainfall during glacial stages may reflect diminished sea and land surface temperatures and the radiative impacts of increased regional dust fluxes. Copyright © 2012 John Wiley & Sons, Ltd.

Description: In regions with seasonal temperate climatic regimes, tree growth is rarely controlled by any single environmental factor. As a consequence, the development of robust palaeoclimate reconstructions has proved challenging. Tree-ring stable carbon isotope ratios (δ 13 C), however, are controlled primarily by photosynthetic rate, not by net growth. Therefore, at sites where climatic controls on tree-ring growth are not strongly expressed, a robust (isotopic) palaeoclimate signal may still potentially be preserved. This hypothesis was tested using a 160-year record of δ 13 C measured from the pooled latewood cellulose of six Quercus petraea L. (sessile oak) trees from Allt Lan-las in West Wales, UK. Raw δ 13 C values were corrected for changes in the isotopic ratio of atmospheric carbon dioxide and for changes in the behaviour of trees due to the increasing availability of atmospheric CO 2 since AD 1850. Strong correlations with local summer temperature and sunshine are reported, and also with the Central England Temperature record over the full length of the isotopic chronology (AD 1850–2010) ( r  = 0.69, P  〈 0.001). We conclude that tree-ring stable isotopes can be used to extract strong palaeoclimate signals even from oak trees growing in a temperate maritime climate. This demonstrates the potential for extracting robust palaeoclimatic information from the very long and well-replicated oak chronologies which have been developed in western and central Europe primarily for dating rather than palaeoclimatic research purposes. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Core HU97048-007PC was recovered from the continental Labrador Sea slope at a water depth of 945 m, 250 km seaward from the mouth of Cumberland Sound, and 400 km north of Hudson Strait. Cumberland Sound is a structural trough partly floored by Cretaceous mudstones and Paleozoic carbonates. The record extends from ∼10 to 58 ka. On-board logging revealed a complex series of lithofacies, including buff-colored detrital carbonate-rich sediments [Heinrich (H)-events] frequently bracketed by black facies. We investigate the provenance of these facies using quantitative X-ray diffraction on drill-core samples from Paleozoic and Cretaceous bedrock from the SE Baffin Island Shelf, and on the 〈 2-mm sediment fraction in a transect of five cores from Cumberland Sound to the NW Labrador Sea. A sediment unmixing program was used to discriminate between sediment sources, which included dolomite-rich sediments from Baffin Bay, calcite-rich sediments from Hudson Strait and discrete sources from Cumberland Sound. Results indicated that the bulk of the sediment was derived from Cumberland Sound, but Baffin Bay contributed to sediments coeval with H-0 (Younger Dryas), whereas Hudson Strait was the source during H-events 1–4. Contributions from the Cretaceous outcrops within Cumberland Sound bracket H-events, thus both leading and lagging Hudson Strait-sourced H-events. Copyright © 2012 John Wiley & Sons, Ltd.

Description: A lake sediment record from the Friedländer Groβe Wiese in northeast Germany was studied to reconstruct summer temperature changes associated with changes in vegetation development during the Weichselian Lateglacial. The record was analysed for pollen, chironomids, and oxygen and carbon isotopes of lake marl. The combination of radiocarbon dates, the presence of the Laacher See Tephra and correlation of lithological and palynological changes with other records from the region indicated that the record encompassed the Allerød to the early Holocene. Pollen assemblages reflect development of birch and later pine-dominated forests during the Allerød, comparable to other sites in the region. Chironomid-inferred mean July air temperatures (C-IT) for this period range between ∼14.0 and 14.8°C. A temporary decrease in C-IT of ∼1°C, a negative shift in the isotope records, and a minor decline of birch may correspond to Greenland Interstadial 1b. Even though the transition to the Younger Dryas appears to be affected by reworking and redeposition processes, a drop in C-IT to ∼11.1°C is reconstructed for the later part of the Younger Dryas, while it appears that pine locally persisted in the region. Comparison with a nearby pollen record further indicates a local expansion of wetland grasses during this period. At the transition to the Holocene, C-IT increased to ∼15.7°C, while birch and pine forests re-expanded. Copyright © 2012 John Wiley & Sons, Ltd.

Description: To test the potential for developing sub-decadal resolution records of ombrotrophic bog surface wetness (BSW), selected abrupt climate events were identified in cores from four sites in north-west Europe and time-slices over each event were investigated at 2–5-mm resolution using peat humification, testate amoeba and plant macrofossil analyses. Age–depth models based on radiocarbon, spheroidal carbonaceous particle and tephra dates were applied and the error in these models was used to determine the effective temporal sampling resolution, which in most cases was sub-decadal. Fine-resolution results revealed some inconsistencies in the co-variability of individual proxies and there was a lack of correspondence between some results from adjacent cores. However, we found evidence of abrupt shifts in BSW occurring over ca. 5–20 years, indicating a more rapid proxy response than identified in previous research. To maximize potential temporal resolution and produce reliable sub-decadal BSW data in future research, we recommended that peat-based studies should obtain the best possible chronological control, focus on sites with high species diversity and rapid accumulation rates and perform replicate coring, or use open peat sections where the stratigraphy can be clearly seen, to assess intra-site differences in microtopography. Site-specific factors should be a primary consideration in the selection of sites for future fine-resolution research. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Establishing the precise timing of continental glacial dynamics and abrupt high-latitude climate events is crucial to understanding the causes of global climate change. Here we present multi-proxy records in a lake sediment core from arid Inner Mongolia (Wuliangsuhai Lake) that show two distinct glacially derived sedimentation events at ∼26.2–21.8 and ∼17.3–11.5k cal a BP. Fine sediments from the Last Glacial Maximum separate these glacially derived coarse sediments. Within these intervals, the occurrence of granite clasts at ∼24–23.5, 17.3–17 and 15.6–14.1k cal a BP implies either sediment discharge by meltwater as well as strong current flow in the Yellow River and/or sediment influx through hill-slope mass wasting and landsliding from the nearby Yin Mountains. Surface microfeatures of quartz grains and spot elemental analysis of black specks in these intervals, however, indicate that physical weathering is dominant and that the provenance of the rocks is probably from a glacial source. To the best of our knowledge, this is the first time glacier-derived materials have been detected in any desert lake in the Yellow River basin. The occurrence of granite clasts roughly correlates with Heinrich events in the North Atlantic, suggesting synchronous ice sheet dynamics in high- and mid-latitude regions during the Last Glacial period. Although our data provide unprecedented evidence for the influence of glacier-related processes in arid Inner Mongolia, further well-dated records are clearly needed to re-evaluate the correlative inference drawn between granite clast layers in Wuliangsuhai Lake and Heinrich events in the North Atlantic. Copyright © 2012 John Wiley & Sons, Ltd.

Description: We analysed charcoal and pollen from sediments obtained from two lakes in the northwestern mixed-wood Canadian boreal forest in order to reconstruct fire-return intervals and vegetation dynamics over the last 8000 years. Sites were selected with contrasting soil properties (mesic versus dry-sandy soils), allowing an estimation of the potential influence of soils on long-term vegetation and fire dynamics. The sites likely experienced fewer fires during the period extending from 8000 to 4000 cal. a BP than over the last 4000 years. At both sites, eastern white pine ( Pinus strobus ) populations were most extensive shortly after deglaciation, with vegetation later shifting towards mixed woodlands with less P. strobus and more extensive Picea and Pinus banksiana populations. This gradual vegetation shift was probably induced by the establishment of colder and moister conditions along with a fire-regime change. In spite of the parallel long-term vegetation trajectories, vegetation composition differed between the two sites in both the past and present. Whereas Picea was more abundant at the mesic site, the fire-adapted P. banksiana populations were more extensive at the sandy-soil site. These differences in vegetation composition indicate that, in addition to climate changes and fire occurrence, soil properties also influenced vegetation dynamics. A likely increase in fire frequency in the Canadian boreal forest during the 21st century might therefore favour the expansion of these two disturbance-adapted trees with spatial heterogeneity in the populations due to varying soil types. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The current detailed chronostratigraphic framework of the last 1 Ma of an eastern Mediterranean sequence (Haifa Bay, Israel) aims to examine the relative roles of sea-level changes, climate and tectonics. Seven continuous marine cores, up to ∼120 m long, were recovered from shallow water depths. The cores were dated by optically stimulated luminescence, 14 C, magnetostratigraphy, 230 Th/ 234 U, 26 Al/ 10 Be, occurrence of index fossils and correlated to the global sea-level curve and Marine Isotope Stages (MIS). The sedimentary sequence accumulated during the last ca. 1.0 Ma consists of 21 transgression–regression units with hiatuses between them. Five marine/terrestrial cycles, which occur in the lower part of the sequence, are attributed to the Jaramillo subchron and the Brunhes–Matuyama boundary, and correspond to MIS 29–21. The top ∼50 m includes three sedimentary cycles deposited in the last ca. 400 ka. The regressive phases during this interval correspond to Glacial MIS 8, 6 and 2, while the transgressions correspond to Interglacial MIS 11, 7, 5 and 1. Thus, for the first time, this study documents the longest Quaternary succession dated so far in a key area of the Levant, sensitive to global history of sea-level changes and glacial/interglacial fluctuations. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Relative sea-level (RSL) change is reconstructed for central Cumbria, UK, based on litho- and biostratigraphical analysis from the Lateglacial to the late Holocene. The RSL curve is constrained using ten new radiocarbon-dated sea-level index points in addition to published data. The sea-level curve identifies a clear Lateglacial sea-level highstand approximately 2.3 m OD at c. 15–17 k cal a BP followed by rapid RSL fall to below −5 m OD. RSL then rose rapidly during the early Holocene culminating in a mid-Holocene highstand of approximately 1 m OD at c. 6 k cal a BP followed by gradual fall to the present level. These new data provide an important test for the RSL predictions from glacial isostatic adjustment models, particularly for the Lateglacial where there are very little data from the UK. The new RSL curve shows similar broad-scale trends in RSL movement predicted by the models. However, the more recent models fail to predict the Lateglacial sea level highstand above present reconstructed by the new data presented here. Future updates to the models are needed to reduce this mismatch. This study highlights the importance for further RSL data to constrain Lateglacial sea level from sites in northern Britain. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Pluvial lakes were abundant in the southwestern United States during Pleistocene glaciations, particularly in the Great Basin. Many of these lakes occupied closed basins; therefore, fluctuations of their water surface elevations are valuable sources of paleoclimate information. Histories of the largest lakes are well constrained, whereas dozens of smaller lakes that were present in this region have received relatively little scientific attention. Given their dimensions, these smaller lakes were climatically sensitive and can offer important information about Quaternary climate variability. Here we present new ages for the highstands of three previously undated small lakes based on radiocarbon dating of gastropod shells recovered from beach ridges. These results are combined with other published and unpublished 14 C ages to yield an extensive compilation of highstand shoreline ages for lakes of all sizes throughout the southwestern US. The results indicate that although some lakes reached highstands during the Last Glacial Maximum, the strongest temporal correspondence is between highstands and Heinrich Event H1. These results are consistent with speleothem-based reconstructions of effective moisture in the southwestern US, which show increased precipitation during stadials of the last glacial cycle. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Palaeoshorelines, highstand lacustrine sediments and lakeshore terraces are preserved around saline lakes in the arid Qaidam Basin. Previous research indicates that the chronology of a mega-paleolake in the Qaidam Basin during the late Pleisotocene is controversial. Here we report quartz optically stimulated luminescence (OSL) age estimates of highstand lacustrine sediments, shoreline features and geomorphic exposures that contribute to a revision of the lake level history of Gahai and Toson lakes in the north-eastern Qaidam Basin, on the northeastern Qinghai–Tibetan Plateau (QTP) margin. The results imply that: (i) high lake levels at Gahai and Toson lakes based on quartz OSL dating occurred at 85–72, 63–55, 31, 5.4 and 0.9–0.7 ka, probably corresponding to periods of warm and wet climate; (ii) periods of high lake levels are almost synchronous with other lakes on the QTP (e.g. Qinghai and Namco lakes), with the highest late Pleistocene levels occurring during Marine Oxygen Isotope Stage 5; and (iii) highstand phases on the QTP are out of phase with those of low-latitude lakes in the southern hemisphere, possibly driven by solar insolation variability in the low-latitude region. Copyright © 2012 John Wiley & Sons, Ltd.

Description: The location and intensity of the austral westerlies strongly influence southern hemisphere precipitation and heat transport with consequences for human society and ecosystems. With future warming, global climate models project increased aridity in southern mid-latitudes related to continued poleward contraction of the austral westerlies. We utilize Antarctic ice cores to investigate past and to set the stage for the prediction of future behaviour of the westerlies. We show that Holocene West Antarctic ice core reconstructions of atmospheric circulation sensitively record naturally forced progressive as well as abrupt changes. We also show that recent poleward migration of the westerlies coincident with increased emission of greenhouse gases and the Antarctic ozone hole has led to unprecedented penetration, compared with 〉100,000 years ago, of air masses bringing warmth, extra-Antarctic source dust and anthropogenic pollutants into West Antarctica. Copyright © 2012 John Wiley & Sons, Ltd.

Description: This paper reports the discovery of a rare partial skeleton of a woolly rhinoceros ( Coelodonta antiquitatis Blumenbach, 1799) and associated fauna from a low Pleistocene terrace of the River Tame at Whitemoor Haye, Staffordshire, UK. A study of the sedimentary deposits around the rhino skeleton and associated organic-rich clasts containing pollen, plant and arthropod remains suggests that the animal was rapidly buried on a braided river floodplain surrounded by a predominantly treeless, herb-rich grassland. Highlights of the study include the oldest British chironomid record published to date and novel analysis of the palaeoflow regime using caddisfly remains. For the first time, comparative calculations of coleopteran and chironomid palaeotemperatures have been made on the same samples, suggesting a mean July temperature of 8–11 °C and a mean December temperature of between −22 and −16 °C. Radiocarbon age estimates on skeletal material, supported by optically stimulated luminescence ages from surrounding sediments, indicate that the rhino lived around 41–43 k cal a BP. The combined geochronological, stratigraphic and palaeoenvironmental evidence places the assemblage firmly within the Middle Devensian (Marine Oxygen Isotope Stage 3). This would agree with other regional evidence for the timing of aggradation for the lowest terrace of the Trent and its tributary systems. Copyright © 2012 John Wiley & Sons, Ltd.

Description: We present a record of peatland development in relation to climate changes and human activities from the Palomaa mire, a remote site in northern Finland. We used fine-resolution and continuous sampling to analyse several proxies including pollen (for vegetation on and around the mire), testate amoebae (TA; for mire-wetness changes), oxygen and carbon isotopes from Sphagnum cellulose (δ 18 O and δ 13 C; for humidity and temperature changes), peat-accumulation rates and peat-colour changes. In spite of an excellent accumulation model (30 14 C dates and estimated standard deviation of sample ages 〈1 year in the most recent part), the potential to determine cause–effect (or lead–lag) relationships between environmental changes and biotic responses is limited by proxy-specific incorporation processes below the actively growing Sphagnum surface. Nevertheless, what emerges is that mire development was closely related to water-table changes rather than to summer temperature and that water-table decreases were associated with increasing peat-accumulation rates and more abundant mire vegetation. A rapid fen-to-bog transition occurred within a few years around AD 1960 when the water table decreased beyond the historical minimum, supporting the notion that mires can rapidly shift into bogs in response to allogenic factors. Copyright © 2012 John Wiley & Sons, Ltd.

Description: This paper presents the first terrestrial age constraints from the outer continental shelf for the maximum extent of the NW sector of the last British–Irish Ice Sheet. Cosmogenic 10 Be ages from eight glacially transported boulders on the island of North Rona show that the Late Devensian (Late Weichselian) British–Irish Ice Sheet overrode the island at its maximal stage and retreated c . 25 ka BP. These new dates, supported by other geological evidence, indicate that the north-western part of the ice sheet was most extensive between 27 and 25 ka BP, reaching the outer continental shelf during the global eustatic sea-level minimum at the Last Glacial Maximum. Copyright © 2012 British Geological Survey/Natural Environment Research Council copyright 2012. Reproduced with the permission of BGS/NERC. Published by John Wiley & Sons, Ltd.

Description: This paper presents two dinoflagellate cyst records from the south-western shelf of the Black Sea. A new site, MAR05-13, from the Sakarya shelf is described and placed into context with site MAR02-45, ∼250 km distant on the Thracian shelf. The records provide a centennial resolution of surface water conditions in the Holocene. Analysis of the data suggests that the surface salinity of the south-western shelf increased in a gradual and progressive manner. In the period ∼11 000–9000 cal a BP the assemblages suggest surface-water salinities between 7–13 psu. The initial arrival of euryhaline species, ∼8100 cal a BP, is linked to the reconnection of the Black Sea and Marmara Sea. The suggested surface water changes related to the reconnection took approximately 1000 years. Following this initial change in assemblages, a further increase in the number of euryhaline species is noted between 5000 and 4000 cal a BP. This is linked to the establishment of more saline surface-water conditions, close to present-day values. The record for MAR05-13 highlights the complexity of the changes in cyst assemblages during the mid-Holocene. Copyright © 2012 John Wiley & Sons, Ltd.