Abstract: Major ion series developed from new subannual scale sampling of an ice core from central Greenland are calibrated with instrumental series of atmospheric sea-level pressure recording major marine (Icelandic Low) and terrestrial (Siberian High) atmospheric circulation systems to provide proxy records of atmospheric circulation over the past 1400 years. Examination of the proxy records reveals: major changes in behaviour of these systems c. ad 1400, multidecadal- and centennial-scale periodic components, characterization of mean sea-level pressure anomaly fields during the ‘Little Ice Age’ and the ‘Mediaeval Warm Period’, the potential role of solar forcing, coupled ocean-atmosphere associations, and a perspective within which the characteristics of instrumental-era climate can be assessed.

Abstract: A unifying attribute of all forms of paraglacial response is that deglaciation results in the exposure of unstable or metastable sediment sources that are subsequently tapped by a wide variety of processes over a wide range of timescales. The ‘paraglacial period’ in different geomorphological contexts is therefore con ditioned by two variables: glacially conditioned sediment release and rate of sediment reworking. Under steady-state conditions, the latter may be approximated by an exhaustion model in which sediment yield is related to the amount of remaining ‘available’ sediment by a negative exponential function. This model offers an approximation for the behaviour of primary paraglacial systems in which glacigenic sediment sources are not replenished. The long-term behaviour of secondary (primarily ‘ uvial) paraglacial systems in which sediment inputs include both in situ and reworked glacigenic sediment appears intrinsically more complex, but consistent with an exhaustion model if initial sediment avai...

Abstract: Quantitative reconstructions are made of Holocene changes in climatic and environmental conditions from analyses of pollen, chironomids and diatoms in identical stratigraphic levels of a sediment c ...

Abstract: More than 200 000 ring-width measurements from 384 trees were obtained for 20 individual sites ranging from the lower to upper local timber-lines in the Northwest Karakorum of Pakistan and the Southern Tien Shan of Kirghizia. Samples were obtained predominantly from juniper species ( Juniperus) and were analysed to reconstruct regional climatic variation patterns in Western Central Asia since ad 618. Site distri- bution represents diverse ecological conditions (e.g., combinations of temperature and moisture stress) within the Karakorum and Tien Shan mountains, permitting both intra-montane and inter-montane comparisons of chronologies. Three different types of chronologies ree ecting interannual-, decadal- and centennial-scale ring- width variations were calculated: a statistic skeleton-plotting technique was used to identify ring-width pointer years (interannual); a 101-year kernel e lter was used to identify decadal-scale variations; and, for a subset of long-lived trees, the mean ring-width of the entire single series was used to identify centennial trends. After extracting and calibrating each of these three distinct wavelengths in ring-width variation, the results were combined into a comprehensive reconstruction ree ecting primarily temperature e uctuations in Western Central Asia since ad 618. The nature and the temporally changing strength of the climatic signals of this reconstruction are discussed in detail. A maximum latewood density record of Pinus tienschanica from Central Tien Shan was used as a predictor series to calibrate and validate tree-ring-width variation. In so doing, we link our results to the circumpolar maximum latewood-density network (Briffa et al., 1998a; 1998b; Schweingruber and Briffa, 1996).

Abstract: Anticipating the consequences of climatic change for fire requires understanding of the causes of variation in historical fire regimes. We assessed the influence of annual and decadal variation in climate on fire regimes of ponderosa pine-dominated forests in eastern Oregon and Washington using existing, annually dated tree-ring reconstructions (1687–1994). In four watersheds, we compared the extent of low-severity fires (total area burned each year) to precipitation and the Southern Oscillation Index, a measure of variation in El Nino-Southern Oscillation (ENSO), which affects weather in this region. At the annual scale, large fires burned during dry years and El Nino years (low SOI) in all watersheds while small fires burned regardless of variation in these climate parameters. Large fires also burned during relatively wet years and La Nina years (high SOI) in one watershed, indicating that local factors can override regional climate controls in some locations. Climate from previous years did not influen...

Abstract: The oxygen-isotope composition of local precipitation (delta(18)O(P)) is reconstructed from carbonate lake-sediment components in a sediment core covering the last 10000 calendar years from Lake Tibetanus, a small, hydrologically open, groundwater-fed take in the Abisko area, northern Sweden. Comparison of the delta(18)O(P) history with a pollen-based palaeotemperature record from the same core clearly reveals pronounced deviations from the normally expected temporal delta(18)O(P)-temperature relation (so-called 'Dansgaard relation') that may be a function of changing oceanicity. The transition from relatively moist, maritime conditions in the early Holocene to a much drier climate after 6500 cal. BP is reflected by major changes in forest extent and composition as recorded by pollen and plant macrofossil data. At the time of maximum influence of westerly air-mass circulation (high zonal index) c. 9500 cal. BP, brought about by high summer insolation and enhanced meridional pressure gradients. delta(18)O(P) at Lake Tibetanus was about 2%, higher than would be predicted by the modem isotope-temperature relation, The occurrence of long-term changes in delta(18)O(P)-temperature relations, which are more sensitive measures of palaeoclimate than either delta(18)O(P) or temperature alone, needs to be taken into account when extracting palaeoclimatic information from continental oxygen-isotope records. (Less)

Abstract: Patterns of summer temperature over the Northern Hemisphere, obtained from a calibration of a treering network, are presented for every year from 1600 to 1877 The network of tree-ring density chronologies is shown to exhibit spatially coherent modes of variability These modes closely match summer half-year tempera ture variations, in terms of similar spatial patterns and similar temporal evolution during the instrumental period They can, therefore, be considered to be proxies for the temperature patterns, and time series for the eight most dominant patterns are presented back to the late seventeenth century The first pattern represents spatially coherent warming or cooling and it appears to respond to climate forcings, especially volcanic erup tions Most other patterns appear to be related to atmospheric pressure anomalies and they can be partially explained by heat advection associated with anomalous atmospheric circulation This provides the potential for reconstructing past variations in atmospher

Abstract: Remains of subfossil Siberian larch trees in the Holocene deposits of the Yamal Peninsula (Western Siberia) have been collected in order to develop a continuous, multimillennium tree-ring-width chronology. This work has produced a calendar-age dated 4000-year (2000 bc to ad 1996) series. From these data, summer- temperature variability in this region has been estimated on annual to multidecadal timescales. Radiocarbon dating of selected older material shows that the oldest subfossil wood is 9400 years old and the dates of the sampled material are generally distributed evenly through time. It will, therefore, be possible to develop a tree- ring chronology for more than nine millennia. An initial assessment of long-term e uctuations in Yamal summer warmth has been realized through the reconstruction of tree-line dynamics using a combination of dendrochron- ological (absolute) dated material and less precisely (radiocarbon) dated older subfossils.

Abstract: Midsummer (July) temperatures are reconstructed for the last 7500 years using the long ring-width chronology of Scots pine (Pinus sylvestris L.) from northern Finland. The chronology was built using regional curve standardization (RCS), which allows for long-term (low-frequency) variability to be extracted from this annually resolved record of 1087 samples from living trees and subfossil timber. Short-and long-term changes in reconstructed July temperatures are presented. The regression model accounts for 37% of the dependent instrumental temperature variance between ad 1879 and 1992. The warmest 30-year periods were ad 560–531, ad 560–531, 1190–1161 bc and ad 1541–1570, and the coldest 5240–5211, 5150–5121 and 3710–3681 bc. The warmest 100-year periods were ad 1501–1600, 600–501 bc and 300–201 bc, and the coldest 5200–5101, 2500–2401 and 1500–1401 bc. Broad comparisons are made with dendrochronological, lacustrine and glacial proxy evidence.

Abstract: A brief review is presented of the progress, to date, in constructing a long, continuous ring-width chronology from living and subfossil Siberian larch (Larix gmelinii) in the eastern part of the Taimyr peninsula. A near 2500-year chronology running up to the present has been assembled and several shorter, earlier series have been produced that are dated approximately on the basis of radiocarbon dates. A description is given of the production of separate early summer and annual mean temperature histories based on the recent chronology, spanning more than 2000 years. These two reconstructions are based on alternative methods of statistical processing of the measured tree-ring data. The early summer and annual reconstructions agree well in the long- term components of their variability, providing evidence for anomalous warmth in the third, tenth to twelfth, and twentieth centuries, and a prolonged cool period throughout the sixteenth and seventeenth, and in the early nineteenth centuries. The mean growth and other statistical parameters of the earlier chronologies also suggest that conditions for tree growth were very favourable in the earlier Holocene, particularly in the fourth millen- nium BC. This is strongly indicative of an early Holocene Climatic Optimum in Taimyr at that time. Other material in hand, and earlier published radiocarbon dates, demonstrate the feasibility of constructing continuous ring-width chronologies and temperature estimates extending throughout all of the last 8000 years.

Abstract: The geochemistry of dated sediment cores from Lake Huguangyan (21o9¢N, 110o17¢E), tropical South China, reveals distinct stratigraphical patterns in total organic and inorganic carbon (TOC, TIC), biogenic silica (BS) and total nitrogen (TN) over the past 1400 years. In this hydrologically closed lake, TIC variations may reeect changes in the precipitation/evaporation ratio, which controls the evaporative enrichment of carbonate. TOC, BS and TN in the sediment are proxy indicators of lake productivity and nutrient input, which we believe are linked to local precipitation. High TIC content correlates with low concentrations of TOC, BS and TN, and indicates two drought episodes dated to ad 670-760 and ad 880-1260 in the sediments of Lake Huguan- gyan. Local historical chronicles support these data, suggesting that the climate of tropical South China was dry during the 'Mediaeval Warm Period' (MWP) and wet during the 'Little Ice Age' (LIA). The detected MWP drought is temporally correlated with evidence for lower precipitation on the Guliya (China) and Quelccaya (Peru) ice caps, and with increased salinity in Moon Lake (US Great Plains).

Abstract: Holocene forested coastal dunes of different morphology fringe the Atlantic coast of southwest Aquitaine Infra-red stimulated luminescence (IRSL) dating has been applied to sands from these dunes in the Aquitaine region in order to test the validity of dune-classification theories The ages obtained from the dunes show three phases of sand invasion and dune development during the late Holocene: 3000-4000 years ago; 900-1300 years ago; 250-550 years ago The timing of the most recent phase of sand mobilization as dated by IRSL, is supported by historical maps and records from the fifteenth to the eighteenth centuries AD, showing problems for human settlement in the region and village abandonment due to dune drift Sand invasion is driven by an increase in frequency of severe storms in the North Atlantic associated with the cooler periods of the ‘Little Ice Age’ and early 'Mediaeval Warm Period' The dunes emplaced 900-1300 years ago were naturally fixed by a mixed deciduous and maritime pine forest durin

Abstract: Some 2600 bog oaks have been dated from German, Dutch and Irish bogs covering the period 6000 bc to ad 1000. The ring patterns of these ' bog oaks' are characterized by recurrent, long-term growth depressions. In addition, obvious changes in the temporal distribution of the bog-oak trunks throughout the Holocene are found. Both features were probably caused by unfavourable growth conditions, which are most likely linked to changes in site hydrology. We use a new variable, ' annual mean age' , as a tool to analyse the population dynamics of bog oaks in more detail, enabling the detection of synchronous intersite and interre- gional changes. It is calculated as the arithmetic mean of the age of all trees in each calendar year. We performed the calculation on regional (Germany, The Netherlands, Ireland) subsets of the bog-oak series. Abrupt changes in annual mean age are taken to indicate periods of generation change. We e nd good agreement for the interval from 5000 bc to 2000 bc between the continental (combined German and Dutch) and the Irish mean-age chronologies. Most changes in population dynamics correspond with contemporary changes in the associated regional tree-ring chronologies. It is concluded that the observed changes in population dynamics and growth activity are responses to common environmental forcing, most likely related to climate.

Abstract: Diatom assemblages from a high-resolution core on the north Icelandic shelf reveal a general late Holocene cooling trend, which is interrupted by three relatively warm periods. Diatom data from sur...

Abstract: Following the Younger Dryas, the e rst evidence of glacial activity in southern Norway in response to climatic change occurred during the early Holocene, when terminal moraines from the Erdalen Event formed beyond the position of later 'Little Ice Age' moraines. In front of present outlet glaciers on both sides of the Jostedalsbreen ice cap, sets of pre-'Little Ice Age' marginal moraines have been morphostratigraphicallycorre- lated with the Erdalen Event. The lithostratigraphyin a peat bog at Hellemyrane in Jostedalen, western Norway, provides e rm evidence for a two-phase Erdalen Event associated with two glacier readvances of Nigardsbreen at the Preboreal/Boreal transition. Radiocarbon dates from the peat bog give age estimates for the two phases: the e rst Erdalen Event readvance took place between 10 100 and 10 050 cal. BP, while the second occurred close to 9700 cal. BP. The lowering of the equilibrium-linealtitude (ELA) during these readvances is estimated using the 'Little Ice Age' ratio (LR) approach to be about 230 m and 215 m, respectively. The e rst readvance is attributed to an increase in winter precipitation, while the second readvance may have been primarily caused by a marked drop in summer temperature which reactivated already existing ice masses.

Abstract: Palaeomagnetic analyses were conducted on two varved lake-sediment sequences in northern Sweden. The magnetic properties of the sediment sequences are dominated by stable single-domain magnetite with characteristics typical of bacterial magnetosomes. Alternating field demagnetization measurements indicate that the single-domain magnetite is the dominant carrier of a stable natural remanent magnetization. Temporal variations in inclination and declination were obtained from a total of four cores and the data points were stacked according to their independent calendar-year (varve) ages. Statistically significant patterns in inclination and declination form a regional palaeomagnetic secular variation (PSV) curve, which possesses features that are identical in form to the UK Holocene PSV master curve. However, the calibrated radiocarbon ages of UK features identified prior to 1500 BC are approximately 500 years older than their Swedish varve-dated equivalents, which points to dating errors and/or drifting of the geomagnetic field. The sediments meet the uniformity criteria proposed for palaeointensity reconstruction and estimates of relative geomagnetic field intensity are calibrated against global dipole-moment compilations. A calculated nuclide production curve is derived from the reconstructed geomagnetic field intensity, which empirically demonstrates the dominant modulation of cosmogenic nuclide production by dipole-moment between 5000 BC and AD 1500.

Abstract: Two sea-level records from salt marshes in coastal Maine are derived from foraminiferal analyses and AMS 14 C, 210 Pb, 137 Cs and pollen chronology. Both records cover the period from AD 800 until the present and show corresponding patterns of sea-level change when corrected for trends which could accommodate millennial-scale isostatic adjustments. The records provide a detailed sea-level chronology for the last few centuries and thus link the instrumental (tide-gauge) record with the long-term geological record of sea-level change. Results show that sea level was relatively stable between AD 800 and 1300 and reached a lowstand around AD 1800, which was preceded by an oscillation in the eighteenth century. Since AD 1800, sea levels in the Gulf of Maine have risen by 0.3-0.4 m. The onset of this rise corresponds with regional climatic warming and could be interpreted as thermal expansion of the Gulf of Maine and North Atlantic sea surface. Sea-level rise possibly slowed temporarily during the mid-nineteenth century, but twentieth-century rates are unprecedented in the last millennium and correspond with hemispheric warming.

Abstract: The northward spread of hazel ( Corylus avellana L.) from its glacial period refuges has been studied for over a century. North of the Alps the course of its pollen curve, in both relative and absolute pollen diagrams, differs from those of other early immigrant trees. There is no long ' tail' of low values before the marked ' rise' to high values. The hypothesis presented is that hazel was present as non-e owering trees before- hand, with full pollen production setting in after a stabilization and amelioration of the climate in the early Holocene. This view is based on a comprehensive survey of all the life history stages of hazel in relation to climatic and other factors, together with indications from radiocarbon dates of the ' rise' phenomenon, not of arbitrary pollen percentage values, for sites north of the Alps. The regional and altitudinal differences in 14 C dates, with due regard to the existence of 14 C plateaux, support the hypothesis, as do other independent estimates of the early-Holocene climate in northern Europe. The role of e uctuating seasonal air temperatures and precipi- tation is noted and the need to consider the ecological requirements of all stages of any plant species' life history is stressed.

Abstract: This paper examines variability in surface climate and the relationship with two circulation indices using recently produced 200–250 year long European daily and monthly climatic series. Assessments are made of the influence of circulation indices (zonal over western Europe and average pressure over central Europe) on regional temperature, precipitation and drought series for northern and central Europe. Changes in the circulation are shown to be very important during the winter in northern Europe, but only over western and central Europe in summer. Circulation indices in winter, however, only explain up to 25% of surface-climate variability and, except for the British Isles, do not explain any decadal and longer timescale variability in summer. Extreme temperatures and growing-season and frost-season durations and degree-day series are calcu lated for four sites (Central England, Stockholm, Uppsala and St. Petersburg). Degree-day counts are shown to be very strongly correlated (r > 0.9) to average extend...

Abstract: Large-scale signature years, in which oak growth across much of northern Europe varies consistently, are identified. Postulating that the likely cause of such widespread departures in growth is climatic, it is shown that these years were characterized by pan-European anomalies in soil-moisture availability, rainfall and temperature, with enhanced growth associated with an extended period of increased soil-moisture availability and reduced growth associated with lower temperatures and reduced soil moisture. These climatic anomalies are, in turn, associated with a large-scale and persistent perturbation in the atmospheric circulation that involves the circumpolar vortex and appears related to the Arctic Oscillation. The 2000-year record of signature-year occurrence shows variations in frequency at the decadal and century levels. It is necessary to interpret this record with caution. Nevertheless, these results do confirm earlier suggestions that large-scale climatic information is contained in regional composite archaeological chronologies. With supporting evidence from other sources, it should be possible to extract useful proxy climate data, even though the precise provenance of the timbers from which the records were derived might not be known.

Abstract: The desert/loess transition zone in northern China is sensitive to climate variability, which is con- trolled mainly by the relative strengths of the East Asian summer and winter monsoons. Sandy loess layers found in the Loess Plateau and palaeosol sequences found in the sandy desert demonstrate latitudinal shifts of the southern desert margin over the last 20000 years. Stratigraphic investigations together with radiocarbon and some thermoluminescence dating, show that during the last glacial maximum the desert margin was at its most southerly position (38 °N). During the early Holocene, it moved northward about three degrees in latitude (41°N). At present, the desert margin is again close to its most southerly position (38 °219 N), yet the northern boundary position of modern summer monsoon activity is placed at 41 °459 N, which is close to the estimated Holocene Optimum desert margin (41 °N). This situation cannot be explained from natural climate models. Hence, an external driving mechanism needs to be considered, and the most obvious one is that caused by human activity on the natural environment over the last 3000 years. Historical evidence tends to reinforce this consideration.

Abstract: The spatial and temporal pattern of land degradation in northeastern Iceland during the Holocene is analysed in relation to climatic fluctuations. Tephrochronology is used to date the infer-red terrestrial changes. and remote sensing and geographical information systems to assess the dynamic relationships between topographic relief. geomorphic processes and soil structure. Changes in vegetation and soil cover during the Holocene are found to he more dynamic than previously reported, highlighted by three substantial degradation phases, two of which occurred prior to the recorded Viking settlement in the ninth century AD, c. 5000 BP and c. 2500 BP. The results demonstrate the role of climate in modifying land cover, hence triggering land degradation without anthropogenic influence. However, anthropogenic activity probably had a significant role in the acceleration of the third degradation phase in the sixteenth century AD, when the system was possibly forced beyond its threshold of recovery, resulting in land degradation on a catastrophic scale. (Less)

Abstract: The hydrographic evolution of the R o ´ a de Vigo (NW Spain) during the last 3000 years has been reconstructed using benthic foraminiferal assemblages, stable oxygen isotopes, molecular biomarkers and sea- surface temperatures (SST) reconstructed from the U K9 37 index. Benthic oxygen isotopes and SST records provide evidence of episodic salinity contrasts between surface and bottom waters. The comparison of SSTs with other climate records for the Northern Hemisphere has allowed the inference of oceanographic and climatic signals, which describe the changes in hydrographic conditions of the r oa. In general, two different periods can be recognized. From 975 cal. bc to cal. ad 1000, the organic carbon is mainly of continental origin, benthic foraminiferal assemblages are typical of environments that are poorly oxygenated, rich in organic matter and dominated by eurihaline taxa. Percentages of planktonic foraminifera are low and SSTs are warmer than today. These data suggest a restricted environment where the exchange with open ocean waters was diminished. At cal. ad 1000, an important hydrographic change in the r oa circulation involved an intensie cation of coastal upwelling processes as ree ected in colder SSTs and increases in the contribution of marine organic carbon and planktonic and opportunistic benthic foraminifera. In these conditions, the sediments of the r oa recorded not only local factors but also several well-known Northern Hemisphere climate signals.

Abstract: The time dependency of the regional difference ΔR in the marine radiocarbon reservoir correction is an important issue for the calibration of marine radiocarbon ages and also provides information about past ocean circulation changes. Few measurements of Holocene reservoir corrections are available for the climatically important North Atlantic. We determined ΔR for intervals during the past 6100 years before present (BP) by comparing radiocarbon ages of 31 marine and terrestrial sample pairs from 14 archaeological sites from the coast of Ireland, Scotland and the Orkney Islands. We find that, while a time dependency in ΔR for this region cannot be ruled out, within the error of the determinations, the ΔR appears to have been constant for at least the last 2000 and possibly the last 6000 years. This work results in a recommendation for ΔR of 33 +93 for the region.

Abstract: This paper presents a multiproxy high-resolution study of the past 2600 years for Seebergsee, a small Swiss lake with varved sediments at the present tree-line ecotone. The laminae were identieed as varves by a numerical analysis of diatom counts in the thin-sections. The hypothesis of two diatom blooms per year was corroborated by the 210 Pb and 137 Cs chronology. A period of intensive pasturing during the 'Little Ice Age' between ad 1346 and ad 1595 is suggested by coprophilous fungal spores, as well as by pollen indicators of grazing, by the diatom-inferred total phosphorus, by geochemistry and by documentary data. The subsequent re-oligotrophication of the lake took about 88 years, as determined by the timelag between the decline of coprophile fungal spores and the restoration of pre-eutrophic nutrient conditions. According to previous studies of latewood densities from the same region, cold summers around ad 1600 limited the pasturing at this altitude. This demonstrated the socio-economic impact of a single climatic event. However, the variance partitioning between the effects of land use and climate, which was applied for the whole core, revealed that climate independent of land use and time explained only 1.32% of the diatom data, while land use independent of climate and time explained 15.7%. Clearly land use ineuenced the lake, but land use was not always driven by climate. Other factors beside climate, such as politics or the introduction of fertilizers in the seventeenth and eighteenth centuries also ine uenced the development of Alpine pasturing.

Abstract: Cores recovered from periglacial Lake Le Bourget deep basin (northwestern Alps) were investigated to examine the ine uence of the ' Little Ice Age' (LIA) on terrigenous lacustrine sedimentation. Growing glaciers in the regional watershed induced catastrophic Rhone river e oods and major undere ow deposits in the deep basin during the early e fteenth, the sixteenth and the mid-eighteenth centuries. The LIA is characterized by a decrease in deposition from intere ows from ad ~1550 to 1740 and an increase in deposition from undere ows from ad ~1550 to 1800. On one hand, spectral analyses of the laminations in intere ow deposits reveal 4- 5 years cyclicities from ad ~1440 to 1550, as well as 7- 8 and 13- 14 years cyclicities from ad ~1740 to 1870; on the other hand, spectral analyses of a clay mineral ratio ree ecting undere ow deposits highlight 45- 50 years cyclicities from ad ~1550 to 1800. These pluriannual, decadal and pluridecadal periods are typical of the North Atlantic Oscillation (NAO). A NAO-like period in our data would be a consequence of periodical variations in rainfall and snow accumulation during late autumn and winter over Lake Le Bourget' s watershed.

Abstract: Eastwood, W. J., Tibby, J., Roberts N., Birks, H. J. B., Lamb, H. F. (2002). The environmental impact of the Minoan eruption of Santorini (Thera): statistical analysis of palaeoecological data from Golhisar, southwest Turkey. Holocene, 12 (4), 431-444.

Abstract: A 4.5 m sedimentary sequence collected from Sirok Nýrjes To in northeast Hungary reveals a record of environmental change from 10000 BP to the present day. Palaeoenvironmental analyses (pollen, cha...

Abstract: Soler Glacier is a temperate outlet glacier on the eastern side of the North Patagonian Icee eld in Chile. The glacier is currently receding from its ' Little Ice Age' maximum position, attained sometime between ad 1600 and 1900. Across the snout and foree eld of the glacier is an arcuate belt of well-sorted granule gravel and coarse sand containing tree remains. These sediments are interpreted as reworked glaciolacustrine material, elevated to the glacier surface by thrusting and folding. Radiocarbon dating of samples of tree remains in these reworked glaciolacustrine sediments demonstrates that the glacier overrode this lake bed sometime between ad 904 and ad 1334. In situ tree remains plastered onto a large boulder in front of the glacier constrain this advance to the period between ad 1222 and ad 1342. This advance precedes by several hundred years the maximum ' Little Ice Age' extent of other North Patagonian Icee eld outlet glaciers, suggesting either an early age for the onset of ' Little Ice Age' conditions or a previously unrecognized period of glacier advance. Prior to the advance at c. ad 1222 to ad 1342, Soler Glacier was more recessed than at present, cone rming the dynamic response of Patagonian glaciers to Holocene climatic e uctuations.