variability of el nino southern oscillation activity at millennial timescales during the holocene epoch the variability of el nino southern oscillation enso during the holocene epoch in particular on millennial timescales is poorly understood palaeoclimate studies have documented enso variability for selected intervals in the holocene but most records are either too short or insufficiently resolved to investigate variability on millennial scales1 2 3 here we present a record of sedimentation in laguna pallcacocha southern ecuador which is strongly influenced by enso variability and covers the past 12 000 years continuously we find that changes on a timescale of 2 8 years which we attribute to warm enso events become more frequent over the holocene until about 1 200 years ago and then decline towards the present periods of relatively high and low enso activity alternating at a timescale of about 2 000 years are superimposed on this long term trend we attribute the long term trend to orbitally induced changes in insolation and suggest internal enso dynamics as a possible cause of the millennial variability however the millennial oscillation will need to be confirmed in other enso proxy records

paraglacial adjustment of alluvial fans to the last deglaciation in the snežnik mountain dinaric karst slovenia abstract glaciokarst depressions are major glacigenic depocenters in the dinaric mountain karst areas and often store important information about the timing and nature of glacial processes and paraglacial sediment reworking this study focuses on praprotna draga which is one of the largest glaciokarst depressions in the sne nik mountain dinaric karst with an area of 3 4 km2 and a maximum depth of 140 m the western slopes of the depression are characterized by undulated moraine morphology and alluvial fans are filling its entire floor we present the results on the thickness origin and age of the sediment infill using a complementary geomorphological sedimentological geophysical and dating approach distribution of moraines point to two glacial advances that were associated with two main alluvial fan aggradation phases recognized using the electrical resistivity tomography measurements the youngest alluvial deposits were sampled for cosmogenic 36cl analysis using amalgamated carbonate pebbles the depth profile of 36cl concentrations suggests an age of 12 3 1 7 ka when assuming a likely denudation rate of 20 mm ka 1 since the existence of the younger dryas glaciers in the study area is climatically difficult to explain we tentatively propose that the youngest alluvial deposition in praprotna draga took place after the glacier retreat during the paraglacial period our findings suggest that the time window of paraglacial adjustment in the sne nik mountain was brief and likely conditioned by quick recolonization with vegetation and inefficient surface runoff on deglaciated karst terrain

understanding past climatic and hydrological variability in the mediterranean from lake prespa sediment isotope and geochemical record over the last glacial cycle here we present stable isotope and geochemical data from lake prespa macedonia albania border over the last glacial cycle marine isotope stages 5 1 and discuss past lake hydrology and climate tic oxygen and carbon isotopes as well as responses to climate of terrestrial and aquatic vegetation toc rock eval pyrolysis carbon isotopes pollen the lake prespa sediments broadly fall into 5 zones based on their sedimentology geochemistry palynology and the existing chronology the glacial sediments suggest low supply of carbon to the lake but high summer productivity intermittent siderite layers suggest that although the lake was likely to have mixed regularly leading to enhanced oxidation of organic matter there must have been within sediment reducing conditions and methanogenesis mis 5 and 1 sediments suggest much more productivity higher rates of organic material preservation possibly due to more limited mixing with longer periods of oxygen depleted bottom waters we also calculated lakewater 18o from siderite authigenic glacial and calcite endogenic holocene and show much lower lakewater 18o values in the glacial when compared to the holocene suggesting the lake was less evaporative in the glacial probably as a consequence of cooler summers and longer winter ice cover in the holocene the oxygen isotope data suggests general humidity with just 2 marked arid phases features observed in other eastern and central mediterranean lakes

model evaluation for reconstructing the oxygen isotopic composition in precipitation from tree ring cellulose over the last century the oxygen isotope composition of tree rings is controlled by many factors including temperature amount of precipitation and changes in relative humidity in this study we present a modified leaf water model from dongmann et al radiation and environmental biophysics 11 1974 41 that can be used to calculate the isotopic composition of the source water and thus of precipitation that a tree used during the growing season the calibration of the model was accomplished by comparing a previously measured oxygen isotope tree ring chronology from central switzerland with the swiss network for isotopes in the hydrologic cycle station at bern from 1971 to 1995 and integrating temperature relative humidity data and ring width in particular our efforts focused on understanding the significance of the dampening factor f which we relate to changes in humidity and its variability over both the calibration period 1971 to 1995 and the study period 1913 to 1995 our results indicate that f ranging between 0 27 to 0 49 is variable based on correlation with relative humidity average daily temperature and ring width index using this model we have constructed a record of the oxygen isotope composition of precipitation during the growing season may through september for the last century in central western europe this approach can be potentially used in other locations where isotopic and meteorological data are available to extend records of the isotopic composition of precipitation back in time beyond observational records

pleistocene glacial relief of the central part of mt prokletije albanian alps abstract the central and highest area of mt prokletije albanian alps is situated in northern albania and eastern montenegro at 42 30 n the highest peak is maja e jezerces 2694 m detailed geomorphological mapping was used to reconstruct the positions of former glaciers the longest ropojana glacier had a length of 12 5 km and surface of 20 km 2 others include valbona glacier 9 5 km 10 5 km 2 grbaja glacier 5 km 6 7 km 2 and bogicevica glacier 6 km 6 9 km 2 three series of moraines can be distinguished the lowest at an average altitude of 990 m average ela 1750 m the middle series at 1350 m ela 1942 m and the highest at 1900 m ela 2123 m as no advanced dating methods have yet been used to provide a numerical chronological framework for these features hypotheses are made based on the comparison with the advanced studies of other similar mountains in the mediterranean region the moraines of the first stage lowest series correspond to one of pre lgm glaciations middle or even early wurmian the second stage moraines probably correspond to lgm and the third stage could be attributed to younger dryas the mapping included a number of inactive and active rock glaciers as well as three small active glaciers surface 5 ha and less at 1980 2100 m altitude in the area close to maja e jezerces

geological controls on pleistocene glaciation and cirque form in greece limestone and ophiolite rocks are common across the eastern mediterranean and many of the highest mountains are formed in these rock types in northwest greece pleistocene glacial erosion was much more effective on limestone terrain where pronounced glacial incision and subglacial glacio karst processes produced locally complex topography this enabled pleistocene glaciers to form on a range of slope orientations in contrast to ophiolite terrains where glaciers were strongly controlled by aspect on limestone terrains the largest ice masses formed on south facing slopes whereas in neighbouring higher mountains formed in ophiolite glaciers were much more restricted and predominantly formed on north and east facing slopes

speleothem u th age constraints for the last glacial conditions in the apuan alps northwestern italy abstract during the quaternary several glaciations occurred in the mountain regions around the mediterranean and in recent years new ages have better constrained their timing however this is not the case for the apuan alps a high rainfall mountain chain adjacent to the mediterranean sea here in spite of the widespread evidence for glaciers the complete lack of geochronological information hinders our understanding of glaciation history in this paper we utilize speleothem ages to better constrain the timing of these glacial features we re examine 293 uranium thorium ages from 19 speleothems collected in five caves at different elevations after a period of very low growth between 160 and 132 ka the analysed speleothems grew almost continuously to 75 ka this period was followed by intermittent growth with lower deposition rate and presence of hiatuses until 12 5 12 ka this is consistent with an ice coverage persisting over the apuan alps inhibiting or interrupting the growth of speleothems via the limited availability of groundwater and the scarcity absence of soils this interval is much greater than the time interval that has previously been attributed to the existence of glaciers on the apuan alps which has been assumed to be restricted to marine isotope stage mis 2 instead ice cover probably also appeared in the apuan alps during mis 4 the phase of restarting of growth which may implies the definitive or substantial glacier melts seem to predate the holocene

archaeological silence and ecorefuges arid events in the puna of atacama during the middle holocene this paper briefly summarizes presearch concerning the mid holocene in the western slope of the puna de atacama 20 25 s proxy data and dates from palynological limnological geomorphological archives were compared with data recovered from the archaeological sites in high altitude basins intermediate ravines and piemontane paleowetlands due to exceptionally favorable conditions numerous early holocene archaeological sites were found in contrast the lack of occupations in previously populated areas suggests a decline in human activity during the arid mid holocene in this context two key concepts are introduced ecorefuge or ecological refuge and archaeological silence silencio arqueologico the first refers to the particular favorable locations occupied by human groups during the mid holocene the second provides a better understanding about the impact of the arid interval during this period on human adaptations in the most barren territories of the new world

lake ohrid albania provides an exceptional multi proxy record of environmental changes during the last glacial interglacial cycle multi proxy analyses on core jo2004 1 recovered from lake ohrid 40 55 000 n 20 40 297e 705 m a s l provide the first environmental and climate reconstruction in a mountainous area in southern europe over the last 140 000 years the response of both lacustrine and terrestrial environments to climate change has been amplified by the peculiar geomorphological and hydrological setting with a steep altitudinal gradient in the catchment and a karstic system feeding the lake the karstic system was active during interglacials leading to high carbonate production in the lake and blocked during glacials as a result of extremely cold climate conditions with permafrost in the mountains at the riss eemian transition termination 2 the increase in lacustrine productivity predated forest expansion by about 10 000 years in contrast the late glacial holocene transition termination 1 was characterized by the dramatic impact of the younger dryas which initially prevented interglacial carbonate production and delayed its maximum until the mid holocene in contrast forest expansion was progressive starting as early as ca 38 000 ago the proximity of high mountains and the probable moderating lake effect on local climate conditions promoted forest expansion and contributed to make the surroundings of lake ohrid favourable to forest refugia during the last glacial usually steppic period our study of sedimentology mineralogy geochemistry magnetics palynology and isotopes illustrates the non linear response of terrestrial and lacustrine ecosystems to similar climate events and demonstrates the potential of lake ohrid as an excellent paleoclimatic archive during the quaternary

glacial history of mt chelmos peloponnesus greece mt chelmos in the peloponnesus was glaciated by a plateau ice field during the most extensive pleistocene glaciation valley glaciers radiated out from an ice field over the central plateau of the massif the largest glaciations are likely to be middle pleistocene in age smaller valley and cirque glaciers formed later and boulders on the moraines of these glacial phases have been dated using 36cl terrestrial cosmogenic nuclide exposure dating these ages indicate a late pleistocene age with glacier advance stabilization at 40 30 ka glacier retreat at 23 21 ka and advance stabilization at 13 10 ka this indicates that the glacial maximum of the last cold stage occurred during marine isotope stage 3 several thousand years before the global last glacial maximum marine isotope stage 2 the last phase of moraine building occurred at the end of the pleistocene possibly during the younger dryas

landscape modification in response to repeated onset of hyperarid paleoclimate states since 14 ma atacama desert chile the landscape of the hyperarid atacama desert in northern chile records extremely slow change on earth s surface disputed ages for the onset of hyperaridity range from the late paleogene through the pleistocene a long term paleoclimate record is recorded in a nonmarine basin whose fill is primarily alluvial strata for this setting the primary proxies for climate state are the mineralogical and chemical composition of soil which varies across a precipitation gradient and the landforms and deposits of alluvial fans during the most recent 15 million years five climate related landscape stages are resolved for the pampa del tamarugal sedimentary basin with each successively younger stage inset lower in the local topography than its predecessor the earliest landscape stage is expressed as a set of alluvial strata inherited from a time of arid or semi arid climate ca 14 12 ma the younger four landscape stages generated a composite long lasting exposure surface predominantly hyperarid conditions have persisted since ca 12 1 ma during which four intervals of arid to semi arid climate occurred each wet interval was short lived a million years or less whereas some of the hyperarid periods were lengthy 1 5 m y the hyperarid intervals were roughly 11 5 5 ma 4 5 4 ma 3 6 2 6 ma 2 2 1 ma and repeated intervals during the last 1 m y the onset of hyperaridity ca 12 ma likely reflects the growth of the andes mountains above a climate threshold in contrast sea surface temperature variability likely has controlled atacama paleoclimate changes since the late miocene

timing of glaciation during the last glacial cycle evaluating the concept of a global last glacial maximum lgm abstract it has long been known that mountain glaciers and continental ice sheets around the globe reached their respective maximum extent at different times during the last glacial cycle often well before the global last glacial maximum lgm c 23 19 ka which is formally defined by peaks in global sea level and marine oxygen isotope records however there is increasing evidence from around the world that it was not only mountain glaciers which were asynchronous with the global lgm but also some regions of the large continental glaciers the barents kara ice sheet in northern eurasia together with a majority of ice masses throughout asia and australasia reached their maximum early in the last glacial cycle a few thousand years before the global lgm period the east antarctic ice sheet also reached its maximum extent several millennia before the global lgm in numerous mountainous regions at high mid and low latitudes across the world glaciers reached their maximum extent before marine isotope stage mis 2 in mis 5 4 and 3 this is in contrast to most sectors of the laurentide ice sheet the cordilleran ice sheet the se sector of the fennoscandinavian ice sheet and the alpine ice sheet in central europe which appear to have reached their maximum close to the global lgm in mis 2 the diachronous maximum extents of both mountain glaciers and continental ice sheets during the last glacial cycle means that the term and acronym last glacial maximum lgm has limited chronostratigraphical meaning when correlating glacial deposits and landforms

surface exposure dating of the flims landslide graubunden switzerland abstract sixteen boulder and bedrock surfaces related to the flims landslide volume 8 12 km3 were dated with 36cl and 10be exposure ages range from 4900 250 yr to 15 440 1480 yr including corrections made due to snow cover and karst erosion ages of 11 410 590 yr and 13 340 1090 yr were obtained on bedrock surfaces outside of the landslide zone these are minima for deglaciation of segnes valley and provide constraints on possible amounts of inherited nuclides based on seven boulder ages which range from 8200 260 to 9520 990 yr a mean of 8900 700 years is calculated for the flims landslide we exclude three outliers one significantly older and two significantly younger than the others and the ages from the cassons bedrock site from the mean calculation the latter is excluded as shielding due to snow and vegetation cover is difficult to constrain there the oldest boulder on the landslide yielded an age 15440 1480 yr more than 5000 years older than any other boulder age suggesting that it included the surface of the pre slide bedrock the exposure ages are consistent with a single failure event the erratics and patches of till lying on the landslide debris must have been carried piggy back on top of the landslide rather than having been deposited by the late pleistocene vorderrhein glacier the flims rockslide is about the same age as the kofels 9800 yr and kandertal 9600 yr rockslides all three occurred during the marked transition to warmer wetter conditions during the early holocene

calibration of cosmogenic 36cl production rates from ca and k spallation in lava flows from mt etna 38 n italy and payun matru 36 s argentina abstract published cosmogenic 36cl production rates from ca and k spallation differ by almost a factor of 2 in this paper we determine production rates of 36cl from ca and k in samples of known age containing little cl ca rich plagioclases and k feldspars were separated from a total of 13 samples collected on the surfaces of four basaltic lava flows at mt etna 38 n italy and from a trachyte lava flow at payun matru volcano 36 s argentina eruption ages determined by independent methods range between 0 4 and 32 ka sample site elevations range between 500 and 2500 m corresponding scaling factors were calculated using five different published scaling models four of which consider paleo geomagnetic field variations integrated over the exposure durations the resulting five data sets were then analyzed using a bayesian statistical model that incorporates the major inherent uncertainties in a consistent way spallation production rates from ca and k considering all major uncertainties are 42 2 4 8 atoms 36cl g ca 1 a 1 and 124 9 8 1 atoms 36cl g k 1 a 1 normalized to sea level and high latitude using the scaling method of stone 2000 scaling models that account for paleo geomagnetic intensity changes yield very similar mean values at most 4 if the uncertainties in the independent ages are neglected in the bayesian model the calculated element specific production rates would be about 12 higher our results are in agreement with previous production rate estimations both for ca and k if only low cl i e 20 ppm samples are considered

estimating erosion rates and exposure ages with 36cl produced by neutron activation the isotopic composition of water soluble cl extracted from mineral grains in granitic rocks appears to reflect the relative age of debris flow fan surfaces and the erosion rate of bedrock outcrops our data indicate that some granitic landforms are stable landscape elements eroding on the order of meters to tens of meters per million years samples collected from debris flow fan surfaces of three distinct relative ages show the expected increase of model age with time but the 36cl exposure ages for boulders on any particular surface vary by a factor of more than five the method we used for extracting cl was designed to isolate the 35cl n 36cl production pathway and to simplify the chemical preparation of samples such isolation from fluid inclusions allows direct interpretation of measured 36cl cl ratios but requires a model to predict the thermal neutron production and absorption profile below the rock surface using such a model we find good agreement between measured and predicted 36cl cl for eight samples collected below the ground surface as well as consistency between several groups of samples collected near one another using elemental abundance data for 129 granitic rocks we modeled 36cl cl supported by radiogenic neutrons and find that it varies from 4 to 125 10 15 mean 21 18 1 however from the surface to a depth of 10 m thermal neutrons resulting from muon interactions have the potential to generate more 36cl than do radiogenic neutrons the production of 36cl in the subsurface has important implications for surface exposure dating of young low altitude samples collected from moraines and debris flow or alluvial fans especially at ages where erosion of the boulder surface is significant or where the source area for boulders is at altitudes much higher than the landform to be dated

water chemistry and isotope study of streams and springs in northern chile abstract the relationship between the stable isotopic and chemical composition of rain spring and stream water was studied in the high andes of northern chile the isotopic pattern of the springs is mainly a reflection of the altitude of their recharge areas however processes that occur during snow melting seem to play a major role in the high altitude springs the streams show patterns similar to the springs in the higher part of the basins but their isotopic composition is modified along the river course due mainly to evaporation the difference in chemical composition between the springs at high and intermediate elevations reflects the duration of water rock interaction the best parameter to trace this length of travelling time is the na k ratio which increases as a result of removal of k into alteration minerals k silicates the na cl ratio increases with salinity in springs and decreases in stream water this reflects the different sources of salt whereas the main source of salts in spring water is the dissolution of silicate and sulfide minerals halite accumulations close to the surface is the main salt source in the streams during floods the stream water chemical characteristics change na cl increases with decreased salinity and na k decreases

deglacial hydroclimate of midcontinental north america abstract during the last deglaciation temperatures over midcontinental north america warmed dramatically through the bolling allerod underwent a cool period associated with the younger dryas and then reverted to warmer near modern temperatures during the early holocene however paleo proxy records of the hydroclimate of this period have presented divergent evidence we reconstruct summer relative humidity rh across the last deglacial period using a mechanistic model of cellulose and leaf water 18o and d combined with a pollen based temperature proxy to interpret stable isotopes of sub fossil wood midcontinental rh was similar to modern conditions during the last glacial maximum progressively increased during the bolling allerod peaked during the younger dryas and declined sharply during the early holocene this rh record suggests deglacial summers were cooler and characterized by greater advection of moisture laden air masses from the gulf of mexico and subsequent entrainment over the mid continent by a high pressure system over the laurentide ice sheet these patterns help explain the formation of dark colored cumulic horizons in many great plains paleosol sequences and the development of no analog vegetation types common to the midwest during the last deglacial period likewise reduced early holocene rh and precipitation correspond with a diminished glacial high pressure system during the latter stages of ice sheet collapse

millennial scale changes of surface and deep water flow in the western tropical atlantic linked to northern hemisphere high latitude climate during the holocene there is increasing evidence that the preceding holocene climate was as unstable as the last glacial period although variations occurred at much lower amplitudes however low latitude climate records that confirm this variability are sparse here we present a radiocarbon dated holocene marine record from the tropical western atlantic aragonite dissolution derived from the degree of preservation of the pteropod limacina inflata records changes in the corrosiveness of the bottom water at the core site due to the changing influence of northern versus southern water masses the 18 o difference between the shallow living planktonic foraminifera globigerinoides sacculifer and the deep living globorotalia tumida is used as proxy for changes in the vertical stratification of the surface water hence the trade wind strength at this latitude we compared our data to high latitude records of the north atlantic region a good agreement is found between the aragonite dissolution and the strength in the island scotland overflow water which contributes significantly to the north atlantic deep water this suggests that large scale variations in the atlantic thermohaline circulation occurred throughout the holocene concurrently the comparison of our 18 o with the gisp2 glaciochemical records points to global holocene atmospheric reorganizations seen in both the tropics and high northern latitudes

humidity estimate for the middle eocene arctic rain forest the exquisite preservation of fossilized metasequoia trees that grew near 808n latitude during the middle eocene ca 45 ma in nunavut canada allowed for dd and d 18 o analyses of cellulose techniques previously restricted to wood 30 000 yr old from the isotopic results we determined that the middle eocene arctic atmosphere contained 23 the water found in the region s atmosphere today this water vapor contributed to a middle eocene greenhouse effect that insulated the polar region during dark polar winters

an early advance of glaciers on mount akdag sw turkey before the global last glacial maximum insights from cosmogenic nuclides and glacier modeling abstract for the first time in turkey we report an early advance of glaciers before the broadly defined global last glacial maximum lgm forty one moraine boulders from three glacial valleys on mount akdag 36 54 n 29 57 e 3016 m southwest coast of turkey were dated with cosmogenic 36 cl valleys on the north side of the mountain were filled with few km long glaciers that terminated at elevations of about 2000 m above sea level a s l the pre lgm glaciations reached their maximum positions 2150 m a s l by 35 1 2 5 ka ago 1 ka 1000 calendar years the glaciers readvanced during the global lgm and reached their farthest locations 2050 m a s l by around 21 7 1 2 ka ago later glaciers retreated and shortly stabilized during the lateglacial at around 15 1 0 9 ka ago using the glacier modeling and paleoclimate proxies from the eastern mediterranean we estimated that if temperatures during the lgm were 8 11 c colder than modern which is suggested by paleotemperature proxies from the region precipitation was up to two times more than that of today previous estimates on southwest coast of turkey indicate a similar precipitation value while central turkey requires drier conditions implying regional heterogeneity on lgm climates in turkey

the contrasted response of ash to wetting abstract after a wildfire the soil is covered by ash ash properties depend on vegetation type amount of fuel and fire intensity the ash layer controls the post fire soil hydrologic response but little is known about the effect of ash thickness and ash type on infiltration which is relevant for post fire runoff and soil losses and for ecosystems rehabilitation and restoration this paper analyses the role of i ash type black or white ii thickness 5 15 and 30 mm thick and iii temporal variation 0 15 and 40 days under three simulated rain events 55 mm for 1 h on soil surface hydrology the rainfall was simulated on 0 25 m2 plots and time to ponding runoff and runoff discharge were measured the infiltration rates the initial infiltration rate f0 the steady state infiltration rate fc and the infiltration decay factor k were calculated and the horton infiltration equation applied the results show that soils covered with white ash doubled the runoff rates of soils covered with black ash in general runoff decreases as the ash thickness increases and the runoff decreases with the number of rainfall events after the fire in plots covered with white ash ponding time and k are positively correlated by the ash thickness and f0 and fc are correlated by the rainfall events in three runs ash type and ash depth are key factors on the soil hydrology after a wildfire

accuracy of cosmogenic ages for moraines analyses of all published cosmogenic exposure ages for moraine boulders show an average age range of 38 between the oldest and youngest boulders from each moraine this range conflicts with the common assumption that ages of surface boulders are the same as the age of the landform the wide spread in boulder ages is caused by erosion of the moraine surface and consequent exhumation of fresh boulders a diffusion model of surface degradation explains the age range and shows that a randomly sampled small set of boulders n 3 7 will always yield a lower age limit for the moraine the model indicates that for identical dating accuracy six to seven boulders are needed from old and tall moraines 40 000 100 000 yr 50 100 m initial height but only one to four boulders from small moraines 20 000 100 000 yr 10 20 m by following these guidelines the oldest obtained boulder age will be 90 of the moraine age 95 probability this result is only weakly sensitive to a broad range of soil erosion rates our analysis of published boulder ages indicates that 3 of all moraine boulders have prior exposure and 85 of these boulders predate the dated moraine

measuring erosion with the micro erosion meter contributions to understanding landform evolution abstract we review the contribution made to understanding landform evolution through the use of the micro erosion meter mem and the variant the traversing micro erosion meter tmem the mem has allowed the direct measurement of bedrock erosion in terrestrial and coastal settings as well as of building stone as recorded in mem measurements world wide the average rate of surface lowering on shore platforms is 1 486 mm a 1 and on terrestrial rock surfaces measured lowering rates are on average 0 903 mm a 1 reported means obscure significant variation in rates from a range of environmental settings and lithologies the mem has in a number of examples allowed the identification of the contribution of individual processes in polygenetic settings particularly in shore platform studies the dynamic nature of rock weathering has been highlighted where the tmem has revealed rock surfaces swelling and contracting at time scales ranging from hours to years the mem will continue to provide useful data on erosion rates and processes but the most fruitful investigations will be those that combine the t mem with other techniques that transcend time and space scale issues in erosion and process measurement

the lateglacial and holocene environmental history of the ioannina basin north west greece this study centres on palaeoenvironmental analysis of the upper part of a long core from the partially drained tectonic ioannina basin north west greece the data span the lateglacial and holocene and comprise pollen mollusc magnetic susceptibility loss on ignition and particle size analyses these augment previously published ostracod and stable isotope data from the same sediment sequence the age model for the sequence is based on 19 ams dates five of which were obtained using a novel procedure for the separation of microcharcoal from sediment the pollen data suggest that although temperate woodland expanded at the beginning of the lateglacial only limited woodland contraction occurred during the younger dryas chronozone despite strong evidence for a sharp drop in sea surface temperature in the neighbouring adriatic at this time in contrast large scale vegetational and sedimentological changes occur in concert during the holocene some of which may be ascribed to human impact comparison with other records from the ioannina basin suggests that previous more littoral pollen sequences did not constitute a wholly representative record of lateglacial and holocene vegetational change

multiple dating approach 14c 230th u and 36cl of tsunami transported reef top boulders on bonaire leeward antilles current achievements and challenges abstract dating the transport deposition time of supratidal coarse clast deposits is difficult limiting their value for inferring frequency magnitude patterns of high energy wave events on bonaire leeward antilles caribbean these deposits form prominent landforms and transport by one or several holocene tsunamis is assumed at least for the largest clasts although a large dataset of 14c and electron spin resonance esr ages is available for major coral rubble ridges and ramparts it is still debated whether these data reflect the timing of major events and how these datasets are biased by the reworking of coral fragments as an attempt to overcome the current challenges for dating the dislocation of singular boulders three distinct dating methods are implemented and compared i 14c dating of boring bivalves attached to the boulders ii 230th u dating of post depositional secondary calcite flowstone and subaerial microbialites at the underside of the boulders and iii surface exposure dating of overturned boulders via 36cl concentration measurements in corals approaches ii and iii have never been applied to coastal boulder deposits so far the three 14c age estimates are older than 40 ka i e most probably beyond the applicability of the method which is attributed to post depositional diagenetic processes shedding doubt on the usefulness of this method in the local context the remarkably convergent 230th u ages all pointing to the late holocene period 1 0 1 6 ka are minimum ages for the transport event s the microbialite sample yields an age of 1 23 0 23 ka and both flowstone samples are in stratigraphic order the older onset of carbonate precipitation and younger flowstone layers yield ages of 1 59 0 03 and 1 23 0 03 ka respectively four coral samples collected from the topside of overturned boulders yielded similar 36cl concentration measurements however the computed ages are affected by large uncertainties mostly due to the high natural chlorine concentration after correction for the inherited component and chemical denudation since platform emergence inducing additional uncertainty the calculated 36cl ages cluster between 2 5 1 3 and 3 0 1 4 ka for three of four boulders whilst the fourth one yields an age of 6 1 1 8 ka probably related to a higher inheritance these 230th u and 36cl age estimates are coherent with a suggested tsunami age of

cosmogenic 36cl and 10be ages of quaternary glacial and fluvial deposits of the wind river range wyoming we measured cosmogenic 36 cl in 56 samples from boulders on moraines and fluvial terraces in the vicinity of the wind river range wyoming we also measured 10 be in 10 of the same samples most of the 10 be ages were in good agreement with the 36 cl ages indicating that rock surface erosion rates were very low the oldest moraine investigated the type sacagewea ridge site yielded only a limiting minimum age of 232 ka the oldest moraines in the type bull lake complex also could be constrained only to 130 ka the main sequence of type bull lake moraines yielded age distributions indicating deposition within the intervals 130 to 100 ka and 120 to 100 ka the best estimates are closer to the upper limits of these ranges and associated uncertainties are in the range of 10 to 15 these uncertainties could permit deposition in either marine isotope stage 6 or stage 5d we found no evidence of glacial deposits dating to marine isotope stage 4 both bull lake age moraines from fremont lake on the opposite side of the wind river range and boulders on a fluvial terrace above the wind river gave age distributions very similar to that of the second oldest bull lake advance ca 130 to 100 ka the distribution of boulder ages for pinedale moraines at bull lake indicated deposition between 23 and 16 ka nearly identical to the distribution of 10 be ages previously reported for the type pinedale moraines at fremont lake

relict rock glaciers as indicators of mediterranean palaeoclimate during the last glacial maximum late wurmian in northwest greece relict rock glaciers have been identified and mapped in the high cirques of mount tymphi in the pindus mountains of northwest greece they are periglacial forms and represent the most recent cold stage landforms in an area that displays widespread evidence of pleistocene glaciation it is likely that these features formed during the last glacial maximum late wurmian as talus rock glaciers and beneath small cirque glaciers as debris rock glaciers comparisons with modern rock glacier climate relationships suggests mean annual temperatures of ca 8 9 c lower than present at their time of formation this temperature reconstruction is in good agreement with recent palaeoclimatic reconstructions for the northern mediterranean based on a general circulation model moreover as rock glaciers are typical of cold and relatively dry mountain regions their presence is consistent with palaeobotanical and lake level data suggesting a cold and relatively dry climate for the last glacial maximum in greece however the presence of small cirque glaciers above some rock glaciers suggests that although precipitation must have been low enough to preclude glacier extension down to lower altitudes it was not so low as to inhibit glacier formation entirely copyright 2003 john wiley sons ltd

an oldest dryas glacier expansion on mount pelister former yugoslavian republic of macedonia according to 10be cosmogenic dating we provide a geomorphological analysis of a glacial valley on mount pelister in macedonia three boulders from a frontal moraine were dated with the cosmogenic nuclide isotope 10 be the results demonstrate that the boulders have been exposed since 15 24 0 85 ka this age constrains the formation of the frontal moraine to the oldest dryas cold event this age fits with that of other glacier deposits dated to the older dryas in the alps balkans carpathians and turkish mountains the pelister palaeoglacier has been reconstructed and its equilibrium line altitude extracted returning a value of 2250 m a s l this is in good agreement with the equilibrium line altitudes of most other reconstructed glaciers of the same age in the circum mediterranean mountains demonstrating a comparable response to the oldest dryas event other palaeoenvironmental records near the pelister mountain indicate that the older dryas was here characterized by a cold and remarkably dry event the temporal relationship between older dryas glacier advances in the balkan region and recorded changes in the atlantic thermohaline circulation during the laurentide ice sheet massive ice discharge h1 event confirms the strong climatic link between the pan mediterranean regions and the north atlantic ocean supplementary material geochemical laboratory results are available at http doi org 10 6084 m9 figshare c 3830254

last deglaciation in the central balkan peninsula geochronological evidence from the jablanica mt north macedonia several studies applied numerical age determination methods to examine glacial phases of the central balkan peninsula however the resulting datasets are contradictory meaning that further discussion is needed this study provides 10 be cosmic ray exposure cre ages of a succession of glacial landforms in the jablanica mt north macedonia aiming at a better understanding of late pleistocene glacier development in the area on the basis of the mapped glacial landforms six glacial stages were identified and their mean equilibrium line altitudes elas were estimated the cre ages of five glacial stages from the second oldest to the youngest were determined between 16 8 0 8 0 5 ka and 13 0 0 4 0 9 ka accordingly the most extensive glaciation in the jablanica mt occurred before 17 ka the average ela of the glaciers was 1792 18 m a s l during the largest ice extent and 2096 18 m during the last phase of the deglaciation independent reconstructions of key climatic drivers of glaciological mass balance suggest that glacial re advances during the deglaciation were associated to cool summer temperatures before 15 ka the last glacial stillstand apparently resulted from a modest drop in summer temperature coupled with increased winter snow accumulation in the study area no geomorphological evidence for glacier advance after 13 0 4 0 9 ka could be found on the basis of independent climate proxies we propose that the last glacier advance occurred no later than 13 ka and glaciers were withdrawing during the younger dryas when low temperatures were combined with dry winters

little ice age glaciers in the balkans low altitude glaciation enabled by cooler temperatures and local topoclimatic controls moraine ridges are present in the highest cirques of the durmitor massif in montenegro and post date the widespread pleistocene moraines of this area lichenometry suggests that at least eight glaciers were present in the 19th century and correlate with the culmination of the little ice age in the european alps cooler temperatures combined with local topoclimatic controls including windblown and avalanching snow as well as shading were crucial for the formation and survival of these glaciers below the regional equilibrium line altitude the resultant regional equilibrium line altitude ela was positioned close to the highest peaks between 2400 and 2500 m with local controls such as avalanche windblown snow and shading depressing the ela in the northern cirques to 2130 2210 m this ela position was very low for this latitude and lower than for most glaciers in the european alps at any time during the holocene and even equivalent to many alpine glaciers during the younger dryas today one glacier still survives in montenegro in a deep northeast facing cirque characterized by the largest combined areas of potential avalanche and windblown snow copyright 2009 john wiley sons ltd

resolving seasonality in tropical trees multi decade high resolution oxygen and carbon isotope records from indonesia and thailand abstract dendrochronological techniques have found limited applications in the tropics because of invisible or indistinct banding in wood the seasonal cycles of rainfall and relative humidity in these regions while not sufficient to produce distinct visible rings may still generate seasonal signals in the oxygen isotopic composition of tree cellulose which can be used for climate reconstruction and chronology we explore this approach using trees from indonesia and thailand from three different families multi decade 18o records from javanese cross dated teak rings and bomb radiocarbon dated suar wood lacking visible rings demonstrate the reproducibility of the signal between trees grown at the same locality as well as from wider geographical regions these results confirm predictions that the trees oxygen isotopic signatures reflect an external climatic forcing high resolution 18o records reveal large seasonal cycles up to 4 for javanese suar samples and up to 18 for a thai podocarpus sample we show that the six 18o and 13c cycles measured on a podocarpus match the number of growth years for the period spanning the time of wounding and cutting of the wedge section this result demonstrates that the isotopic cycles found in this tree with indistinct annual rings are indeed seasonal and could be used for chronology we present evidence that stable isotope chronologies of tropical trees also contain insights in tropical tree physiology and growth dynamics

nature and causes of quaternary climate variation of tropical south america abstract this selective review of the quaternary paleoclimate of the south american summer monsoon sasm domain presents viewpoints regarding a range of key issues in the field many of which are unresolved and some of which are controversial 1 el nino southern oscillation variability while the most important global scale mode of interannual climate variation is insufficient to explain most of the variation of tropical south american climate observed in both the instrumental and the paleoclimate records 2 significant climate variation in tropical south america occurs on seasonal to orbital i e multi millennial time scales as a result of sea surface temperature sst variation and ocean atmosphere interactions of the tropical atlantic 3 decadal scale climate variability linked with this tropical atlantic variability has been a persistent characteristic of climate in tropical south america for at least the past half millennium and likely far beyond 4 centennial to millennial climate events in tropical south america were of longer duration and perhaps larger amplitude than any observed in the instrumental period which is little more than a century long in tropical south america these were superimposed upon both precession paced insolation changes that caused significant variation in sasm precipitation and eccentricity paced global glacial boundary conditions that caused significant changes in the tropical south american moisture balance as a result river sediment and water discharge increased and decreased across tropical south america lake levels rose and fell paleolakes arose and disappeared on the altiplano glaciers waxed and waned in the tropical andes and the tropical rainforest underwent significant changes in composition and extent to further evaluate climate forcing over the last glacial cycle 125 ka we developed a climate forcing model that combines summer insolation forcing and a proxy for north atlantic sst forcing to reconstruct long term precipitation variation in the sasm domain the success of this model reinforces our confidence in assigning causation to observed reconstructions of precipitation in addition we propose a critical correction for speleothem stable oxygen isotopic ratios which are among the most significant of paleoclimate proxies in tropical south america for reconstruction of variation of paleo precipitation or sasm intensity however it is already well known that any particular 18o value observed in speleothem carbonate is affected by two processes that have nothing to do with changes in precipitation amount the influence of temperature on carbonate water isotopic fractionation in the cave and the influence of changing 18o of seawater quantitatively accounting for both artifacts can significantly alter the interpretations of speleothem records in tropical south america both adjustments act in the same direction and have the tendency to increase the true amplitude of the paleo hydrologic signal but by different amounts in glacial and inter glacial stages these corrections have even graver implications for the interpretation of tropical northern hemisphere speleothem records e g chinese speleothems where the combined adjustments tend to decrease or even eliminate the true signal amplitude

deglaciation chronology and paleoclimate of the pieciu stawow polskich roztoki valley high tatra mountains western carpathians since the last glacial maximum inferred from 36cl exposure dating and glacier climate modelling abstract exposure dating of abraded bedrock surfaces below glacial trimlines in the pieciu stawow polskich roztoki valley using cosmogenic 36 cl has been applied to determine the deglaciation chronology in the study area nineteen rock samples yielded ages between 21 5 and 9 5 ka the spatial distribution of ages provides evidence of progressive downwasting of glaciers within the study area dates of exposure indicate that the onset of ice volume decrease occurred no later than 21 5 ka this provides evidence that the local maximum glaciation occurred in accordance with the global last glacial maximum lgm the first period of deglaciation in the study area was completed around 18 ka further significant loss of ice volume is confirmed between 15 and 13 ka the spatial distribution of chronological data within the pieciu stawow polskich valley indicates post lgm readvances of glaciers around 17 ka and 12 ka using the glacier modelling and paleoclimate proxies from the study area the early late glacial glacier had been stable with a 9 10 c decrease in temperature and 30 50 lower precipitation in relation to modern conditions the subsequent advance took place with temperatures 6 7 c lower and 10 30 less precipitation the timing of the readvances is nearly synchronous with late glacial advances in the european alps southern carpathians and anatolian peninsula this suggests synchronicity of major climatic fluctuations across central europe and the northern margin of the mediterranean basin

pollen inferred late glacial and holocene climate in southern balkans lake maliq abstract high temporal resolution analysis of pollen records from lake maliq albania provides quantitative estimates of monthly temperature and precipitation changes since the last deglaciation the climate parameters were estimated using the best modern analogue technique with an updated modern pollen climate database composed of 2748 surface samples the record shows two main cooling phases in the maliq area the oldest and younger dryas and a cooling event around 8200 years which suggests that the forcing factors driving climate variations in the north atlantic area since the last glacial period also extended their influence into the mediterranean area the oldest and younger dryas are also characterized by an arid climate and a change in the seasonality of precipitation the summer precipitation tends to be greater during the cooling phases than during the temperate periods the holocene climate is relatively stable and the values of each parameter reach their modern levels except for an arid event between 8300 and 8100 cal bp

major hydrological regime change along the semiarid western coast of south america during the early holocene water availability in the semiarid western coast of chile 30 32 s is conditioned by high interannual precipitation variability reflecting the transition between arid subtropical and moist mid latitude climates in the southeastern pacific ocean a paleoclimate reconstruction based on the latest pleistocene holocene geological record from the quebrada santa julia archeological site in chile 31 50 s and on modern meteorological mechanisms producing alluvial episodes in this region indicates a major change in the rainfall regime shortly after 8600 cal yr bp this together with other paleoclimate proxies along the west coast of south america 34 14 s suggests la nina like conditions 13 000 8600 cal yr bp based on sedimentological and geomorphologic evidence we hypothesized that the absence of heavy rainfall events in northern chile and the new hydrological regime that prevailed ca 8600 5700 cal yr bp in north central chile resulted from an increase in the large scale westerly flow over central chile as expected in near neutral enso conditions this atmospheric circulation anomaly is compatible with an equatorward shift of the influence of the southeast pacific subtropical anticyclone relative to the early holocene prior to the onset of modern enso variability

late pleistocene glaciers in greece a new 36cl chronology abstract glaciers formed in the highest mountains of greece during the late pleistocene but the timing of glacier maxima is poorly understood this paper presents 27 36cl terrestrial cosmogenic nuclide exposure ages from glacial boulders on mount tymphi 2497 m a s l 40on in epirus northwest greece these ages address both a significant geographical gap in mediterranean glacial chronologies and a temporal gap in the glacial history of this region by targeting the previously undated late pleistocene record late pleistocene glaciers were restricted to the cirques and upper valleys of mount tymphi terminal and lateral moraines between 1700 m and 2050 m a s l mark the extent of late pleistocene glaciers on the southern side of mount tymphi moraines marking the maximum extent of late pleistocene glaciation date to 29 0 3 0 ka and 25 7 2 6 ka taking the oldest ages as most representative of moraine emplacement glaciers had retreated to the high cirques by 24 5 2 4 ka during heinrich stadial 2 rock glaciers formed under cold and drier conditions during this period of glacier retreat this 36cl dataset complements published u series ages from secondary calcites in glacial sediments below 1700 m elevation which demonstrate more extensive middle pleistocene glaciations in mis 6 and mis 12 a late pleistocene glacier maxima on mount tymphi at 25 7 29 ka is in good agreement with well preserved outwash sediments dating to 24 28 ka in the voidomatis river record downstream and is consistent with the ioaninna basin pollen record indicating cool and wet conditions most favourable for glacier growth at 25 30 ka

variability in the mean latitude of the atlantic intertropical convergence zone as recorded by riverine input of sediments to the cariaco basin venezuela abstract changes in the strength and position of the intertropical convergence zone itcz are an important component of climate variability in the tropical atlantic the cariaco basin located on the northern margin of venezuela is sensitive to tropical atlantic climate change and its sediments provide a record of past itcz behavior today the cariaco basin experiences two distinct seasons that reflect the annual migration of the atlantic itcz between january and march when the itcz lies south of the equator northeasterly trade winds sit directly over cariaco basin and strong coastal upwelling and dry conditions dominate beginning in june july as the itcz moves north local rainfall reaches a maximum and the upwelling diminishes or disappears here we summarize new and previously published data on the river derived terrigenous fraction of cariaco basin sediments as well as comparisons to other paleoclimate records which together suggest a coherent climatologic response in the tropical atlantic triggered by a pattern of itcz migration that mimics the seasonal cycle during periods of cooler north atlantic ssts on time scales ranging from the little ice age to the younger dryas to the cold stadials of the last glacial decreased detrital delivery to cariaco basin from local rivers suggests a southward shift in the mean latitudinal position of the itcz during warm interstadials and periods of holocene and deglacial warmth northward shifts in itcz position and its belt of convective rainfall are inferred from increased detrital delivery to the basin whether the rapid shifts in itcz position and precipitation recorded by cariaco basin sediments and other regional records reflect a response to forcing originating in the high latitude atlantic or to forcing potentially sourced in the tropics is a key question yet to be fully answered

isotope hydrology of groundwaters in the pampa del tamarugal chile the water resources in northern chile are extremely scarce and development is limited by this this paper discusses the isotope hydrology of groundwaters in the pampa del tamarugal an area of extreme aridity rainfall 1 mm yr whose groundwater resources are mined for the town of iquique as well as for industrial and agricultural purposes the aim of the project was to obtain information on modern recharge and to delineate if possible recharge environments to obtain the necessary background information a precipitation survey in the high andes as well as spring and surface water studies were carried out the results show that a well defined meteoric water line exists where 2h 7 8 18o 10 3 and altitude effects depend on air mass movements and cannot be defined without a broader regional and detailed sampling programme however it is still possible to assign maximum altitudes of recharge to springs in the andes and at the eastern border of the pampa del tamarugal comparison of these data with groundwater compositions show that these groundwaters originate from infiltrating surface water rather than directly infiltrated precipitation a dependence of individual groundwater systems on specific quebradas river valleys is recognized however low 14c activities indicate that most of the waters pumped today are fossil and at least several hundreds if not thousands of years old some minor subsurface recharge does occur at the foot of the andes especially at pica where high altitude waters discharge but even there groundwater appears to be a diminishing resource

factors controlling carbonate dissolution rates quantified in a field test in the austrian alps carbonate dissolution rates were investigated by measuring the mass difference of carbonate tablets exposed to natural dissolution for 1 year 70 tablets were distributed over 13 test sites on the north slope of the hochschwab massif in the austrian alps the influences of altitude subsoil vs sub aerial exposure vegetation karst morphology soil humidity sample lithology and sample surface morphology were investigated the observed dissolution rates varied between 13 and 40 m a for subcutaneous samples and about 11 m a for sub aerial exposure outstandingly high rates of 48 m a were observed in a doline and nearly zero rates were measured at a site influenced by seeping spring water a mass balance using high resolution hydrological data was calculated for the klaffer spring which has an average outflow of 4 8 m3 s it indicated a loss of 21 106 kg of carbonate rock per year which gives an average dissolution rate of 95 m a for the catchment area of 83 km2 the dissolution rates of 10 m a from the sub aerially exposed samples are comparable to values from limestone pedestals which were protected from dissolution by glacial erratics for the past 15 ka

spatial and climatic characterization of three glacial stages in the upper krnica valley se european alps abstract the southeastern european alps represent the spot where mean annual precipitation is at its highest in the entire alpine chain accordingly the glacial evolution here might have a different spatial and chronological pattern if compared with other alpine areas this paper discusses geomorphological evidence of three glacial stages from the krnica valley in the julian alps of slovenia and is the first step towards a comprehensive palaeoglaciological studies in this alpine sector very well preserved glacial landforms in the upper krnica valley allowed the reconstruction of glacier surface topographies and corresponding equilibrium line altitudes elas by means of field based geomorphological and sedimentological data and by using geospatial analysis the uppermost frontal moraines belong to the little ice age lia and the corresponding ela is estimated at 1973 m a s l other two stages with the ela depressed by 50 m and 161 m compared to the lia ela suggest early holocene and younger dryas ages of the palaeoglaciers respectively this assumption ensues from absolute age datings and related ela depressions observed elsewhere in the european alps the presence of buried ice under the debris in the krnica cirque imaged through geophysical investigations point to peculiar microclimatic conditions able to preserve relict glacier ice this is favoured by the recursive presence of snow on the ground caused by the extreme summer shading and the significant winter snow recharge triggered by snowblow and avalanche feeding the possible evolution of such relict ice under the ongoing climate warming is also discussed

timing of glaciation in the mediterranean mountains during the last cold stage recent research in the mountains of the mediterranean has attempted to establish the timing of the maximum extent of glaciers during the last cold stage several dating methods have been utilised and new dating frameworks have emerged in key areas in several places multiple dating techniques radiocarbon optically stimulated luminescence u series applied to glacial and associ ated sediments suggest that local glacier maxima preceded the global last glacial maximum lgm ca 18 14 c ka bp 21 cal ka bp by at least several thousand years studies in spain the pyrenees the maritime alps and turkey utilising cosmogenic isotope analyses 10 be and 36 cl have yielded glacial geochronologies with maxima that correlate closely with the marine isotope record of ice volume and the global lgm in some cases the use of different geochronological techniques has led to conflicting evidence for the timing of the local last glacier maxima in the same area from a palaeoclimate perspective glacier climate reconstructions for the local last glacier maxima in the mountains of central italy northern greece and western turkey indicate that climate was wet and cold in italy and greece the local glacier maxima preceded the driest part of the last cold stage as indicated by palaeoecological records by several thousand years for western turkey however recent cosmo genic exposure ages combined with glacier modelling suggest a local last glacier maximum charac terised by cold and wet conditions coinciding with the global lgm the available evidence indicates that a dichotomy is emerging not only in our understanding of the timing of glaciation across the mediterranean but also in the palaeoclimatic interpretations derived from glacial and palaeoecolo gical records copyright 2008 john wiley sons ltd

abrupt variations in south american monsoon rainfall during the holocene based on a speleothem record from central eastern brazil well dated high resolution oxygen isotope records of speleothems in central eastern brazil spanning from 1 3 to 10 2 kyr b p reveal that the occurrence of abrupt variations in monsoon precipitation is not random they show a striking match with bond events and a significant pacing at 800 yr a dominant periodicity present in sea surface temperature records from both the north atlantic and equatorial pacific oceans that is possibly related to periods of low solar activity high 14 c based on the atmospheric 14 c record the precipitation variations over central eastern brazil are broadly antiphased with the asian and indian monsoons during bond events and show marked differences in duration and structure between the early and late holocene our results suggest that these abrupt multicentennial precipitation events are primarily linked to changes in the north atlantic meridional overturning circulation amoc anomalous cross equatorial flow induced by negative amoc phases may have modulated not only the monsoon in south america but also affected el nino like conditions in the tropical pacific during the holocene

chlorine degassing constrained by cosmogenic 36cl and radiocarbon dating of early holocene rhyodacitic lava domes on erciyes stratovolcano central turkey abstract the erciyes stratovolcano in central turkey has several young rhyodacite lava domes that show evidence of clear exposure histories but have hitherto unknown ages we collected 27 surface samples from three volcanic domes namely karagullu perikartin and dikkartin for cosmogenic 36cl dating the perikartin eruption generated a pyroclastic flow which buried trees that were converted to charcoal the radiocarbon 14c dating yielded an average age of 9728 110 cal years b p calibrated using calib 7 1 we analyzed the cosmogenic 36cl ages however were found that they were probably affected by cl degassing of the magma our study suggests that the radiocarbon age indeed lies between the 0 cl degassing 6 8 0 5 ka under nucleogenic 36cl equilibrium and the 100 degassing conditions 9 9 0 6 ka under nucleogenic 36cl disequilibrium which implies a partial cl degassing 93 during the eruption this value is somewhat higher than earlier estimates and the difference may result from the miscalculated nucleogenic and or low energy neutron production of 36cl uncertainties arising from the corrections due to hydrogen rich cover i e snow of lava surfaces or due to unconsidered geological complications our findings provide a novel approach to estimate the cl degassing on young lavas and deliver a new evidence of the holocene volcano chronology of the central anatolia

middle pleistocene cold stage climates in the mediterranean new evidence from the glacial record abstract a major reduction in summer temperatures during a middle pleistocene glacial cycle caused the most extensive glaciation recorded in the mediterranean region glaciers in the mountains of greece formed during marine isotope stage mis 12 474 000 427 000 years bp under climatic conditions characterised by mean summer temperatures at least 11 c cooler than today and annual precipitation of 2300 mm at the equilibrium line altitude 1741 m a s l this represents the coldest mean summer temperatures recorded in greece during at least the last 430 000 years later pleistocene glaciations mis 6 and 5d 2 were characterised by warmer summer temperatures and higher annual precipitation

late pleistocene glacial chronology of the pietrele valley retezat mountains southern carpathians constrained by 10be exposure ages and pedological investigations abstract the southern carpathians are located in the transition zone between mediterranean and continental climates and constituted the major areas of ice accumulation in the carpathians during pleistocene glaciations an absolute glacial chronology had not yet been established in this study we constrain the glacial history of the pietrele valley in the retezat mountains located in the southern carpathians and find that the timing of the late wurmian glacial advance is asynchronous to global climate records likely reflecting changes in moisture availability in the area the former ice extent of two major glacial advances m1 or lolaia glacial advance and m2 or capra judele glacial advance in the valley was reconstructed based on mapping and surveying of glacial features field relations and different pedological weathering indicators of till imply that the m1 glacial advance occurred well before the global last glacial maximum lgm its deposition during the penultimate glaciation is unlikely no boulders suitable for exposure dating were found on m1 moraines seventeen exposure ages show that the moraines of the maximum late wurmian m2 glacial advance were abandoned around 16 1 1 6 ka another late glacial advance m3 or stevia advance occurred during the younger dryas chron as constrained by two exposure ages we suggest that the glacial advance that occurred during the time of the global lgm was less extensive than the m2 glacial advance and the deposits were overrun by the lateglacial m2 glacier as we found no field evidence of glacial deposits between the m1 and the m2 moraines we explain this obvious asynchronity of the local late wurmian ice extent with that of global records of ice accumulation with increased aridity in the carpathians during the global lgm due to a lower sea level the reconstructed late pleistocene equilibrium line altitude ela shows a distinct increase in the trend from the alps and the bavarian forest to the carpathians in comparison to the modern ela this finding supports the high aridity in the study area during the late pleistocene two distinct lateglacial moraines were deposited during times of reported colder and wetter climatic conditions around the north atlantic heinrich events h0 and h1

timing of pleistocene glaciations in the high atlas morocco new 10be and 36cl exposure ages abstract this paper presents data from 42 new samples yielding late pleistocene cosmogenic 10be and 36cl exposure ages of moraine boulders across a series of glaciated valleys in the toubkal massif 4167 m a s l high atlas morocco this represents the first comprehensive pleistocene glacial chronology in north africa and one of the largest datasets from the mediterranean region the timing of these glacier advances has major implications for understanding the influence of atlantic depressions on moisture supply to north africa and the mediterranean basin during the pleistocene the oldest and lowest moraines which span elevations from 1900 to 2400 m a s l indicate that the maximum glacier advance occurred from mis 5 to 3 with a combined mean 10be and 36cl age of 50 2 19 5 ka 1 sd n 12 7 outliers the next moraine units up valley at higher elevations 2200 2600 m a s l yielded exposure ages close to the global last glacial maximum lgm with a combined mean 10be and 36cl age of 22 0 4 9 ka 1 sd n 9 7 outliers the youngest exposure ages are from moraines that were emplaced during the younger dryas with a combined mean 10be and 36cl age of 12 3 0 9 ka 1 sd n 7 no outliers and are found in cirques at the highest elevations ranging from 2900 to 3300 m a s l from moraines predating the younger dryas a large number of young outliers are spread evenly between 6 and 13 ka suggesting a continuing process of exhumation or repositioning of boulders during the early to mid holocene this attests to active seismic processes and possibly intense erosion during this period

a general model of paraglacial landscape response 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

evidence for a younger dryas deglaciation in the galicica mountains fyrom from cosmogenic 36cl abstract this study presents the first cosmogenic 36cl surface exposure data from a moraine in the former yugoslav republic of macedonia fyrom five limestone boulders from an end moraine in the galicica mountains 40 94 n 20 83 e 2050 m a s l were used for cosmogenic 36cl surface exposure dating the 36cl concentrations from the five boulders are identical within their measurement uncertainties ruling out major effects of inheritance erosion or snow cover the calculated ages are very consistent ranging from 11 3 1 3 to 12 8 1 4 ka mean 12 0 6 ka after applying a ca spallation production rate of 56 at g 1 a 1 lsd scaling and correction for 5 mm ka 1 carbonate weathering and 2 snow shielding the applied corrections for weathering and snow shielding cause a shift to older ages in the order of magnitude of ca 5 on average making the production rate the main impact on exposure ages the ages point to a moraine formation during the younger dryas period consistent with the timing of the last deglaciation in the galicica mountains derived from previous geomorphological studies in the area the formation of a glacier was likely favoured by several topoclimatic factors accounting for additional snow input this interpretation is in line with regional studies on glaciation chronologies from sara range fyrom republic of kosovo retezat mountains romania mt chelmos greece mount orjen montenegro and durmitor montenegro lake sediment analyses of prespa republic of albania fyrom greece maliq republic of albania and dojran lakes fyrom greece indicate that cold conditions promoted the formation of a local cirque glacier however studies of sediment records of the adjacent lakes ohrid republic of albania fyrom and prespa do not indicate the presence of a proximal glaciation an explanation might be a combination of the small size of the cirque glacier generating only small amounts of debris and the karstic bedrock which hampers fluvial transport and acts by its aquifer system as a natural sediment trap as the fluvial transport of the sediments to the lakes is absorbed by the karst system

the potential of lake ohrid for long term palaeoenvironmental reconstructions abstract lake ohrid at the macedonian albanian border was likely tectonically formed during the tertiary and therefore is one of the oldest lakes in europe however only a few studies exist concerning the potential of lake ohrid sediments for long term palaeoenvironmental reconstructions within the scope of future potential deep drilling campaigns therefore as a first step a transect of short surface sediment cores was investigated for chronology physical properties grain size and biogeochemistry the results were compared with information derived from a shallow hydro acoustic seismic survey the investigations indicate a rather uniform and bioturbated sedimentation in the central part of the lake basin with mean sedimentation rates of ca 0 5 1 mm year the sediment composition is dominated by authigenetic carbonates diatom frustules or fragments form the major part of biogenic matter deposits as indicated by the relatively high contents of biogenic opal and low contents of total organic carbon and total nitrogen the shallow hydro acoustic seismic survey indicates that horizons of sediment redeposition occur sporadically towards the shore of the lake the sedimentation rate increases and sedimentation is increasingly influenced by local inflows or mass movement processes triggered by tectonic activities thus lake ohrid has a high potential for palaeoenvironmental reconstructions on a multi decadal scale and provides additional information concerning tectonic activity in the region

quaternary uplift along a passive continental margin oman indian ocean abstract crustal movement along the coastline of the arabian sea in oman is quantified along a 72 km long coastal section characterised by staircases of marine terraces an extensive topographic geomorphological and geological survey was conducted on these terraces and an age model based on cosmogenic nuclide 10be 36cl and optically stimulated luminescence dating is presented together with a new approach to extract palaeo shorelines from a high resolution digital elevation model the uplifting crustal block is fault bounded and is composed of obduction related peridotites overlain by shallow marine limestone nine distinct terrace levels are identified and the results indicate continuous uplift between marine isotope stage mis 5a and mis 19 the calculated uplift rates vary along the coastline and a northward tilting of the uplifted coastal block is interpreted as evidence for differential uplift the geomorphology of the terraces proves that the tilting must have taken place after the last interglacial tectonic forcing of the uplift by a crustal forebulge associated with the makran subduction zone is discussed it is also concluded that the uplift involves processes of serpentinisation of the peridotites in combination with karstification of the overlying limestone formations as water is essential for both processes climate change during the quaternary apparently played a significant role in the uplift process as well as hydro isostasy

a late quaternary diatom record of tropical climatic history from lake titicaca peru and bolivia abstract a composite high resolution diatom stratigraphy from three piston cores and one box core in the deep sub basin of lake titicaca reveals large moisture variations during the past 30 kyr in the altiplano region diatom sequences indicate orbital and millennial scale variability in water level and salinity the pelagic freshwater diatom species cyclotella andina and cyclotella stelligera dominate glacial age sediments suggesting that the lake was above its present outlet generally wet conditions continued until 11 000 cal yr bp as indicated by high percentages of freshwater planktonic diatoms large pulses of benthic diatom species between about 11 000 and 10 000 cal yr bp suggest brief intervals of large amplitude declines in lake level during the early holocene 10 000 8500 cal yr bp a freshwater diatom assemblage suggests overflowing conditions pelagic freshwater diatoms are replaced ca 8500 cal yr bp by the salinity indifferent species cyclotella meneghiniana and by benthic taxa indicating the beginning of lake regression during the mid holocene 6000 3500 cal yr bp the abundance of the saline taxon chaetoceros muelleri coupled with high abundances of epiphytic and epipelic diatoms indicates maximum salinity and lowest lake levels in the entire 30 000 year record lake transgression began ca 4000 cal yr bp and the lake achieved modern levels by about 1500 cal yr bp these water level changes imply changes in effective moisture most likely resulting from large precipitation changes precipitation was high throughout the last glacial maximum 21 000 18 000 cal yr bp likely due to an enhanced south american summer monsoon during peak summer insolation in the southern hemisphere in contrast the mid holocene transition was dryer than today in association with an austral summer insolation minimum and the subsequent weakening of the summer monsoon

stable isotopes of a subfossil tamarix tree from the dead sea region israel and their implications for the intermediate bronze age environmental crisis article i nfo n values calibration using modern tamarix stable isotopes in various climatic settings in israel shows direct relationship between isotopic enrichment and climate deterioration particularly rainfall decrease the subfossil tamarix probably reflects an environmental crisis during the intermediate bronze age which subsequently killed the tree 1930 bce this period coincides with the largest historic fall of the dead sea level as well as the demise of the large regional urban center of the 3rd millennium bce the environmental crisis may thus explain the archaeological evidence of a shift from urban to pastoral culture during the intermediate bronze age this was apparently the most severe long term historical drought that affected the region in the mid late holocene

the glacial history of the pindus mountains greece abstract geomorphological evidence for pleistocene glaciation has been mapped in the pindus mountains of northwest greece and the chronology of glaciation in this area has been established through soil profile analysis and u series dating of secondary carbonates calcite formed within glacial deposits three glacial stages are evident in the sedimentological and geomorphological records the earliest and most extensive recorded glaciation predates 350 000 yr b p and was characterized by extensive valley glaciers and ice fields a more recent glaciation occurred before the last interglacial and was characterized by glaciers that reached midvalley positions the last phase of glaciation in greece is recorded by small cirque glacier moraines and relict periglacial rock glaciers the glacial and periglacial sequence on mount tymphi has been used in conjunction with a reference parastratotype the long lacustrine sequence at ioannina to provide a chronostratigraphical framework for cold stage deposits in g

late glacial to holocene climate change and human impact in the mediterranean the last ca 17ka diatom record of lake prespa macedonia albania greece lake prespa macedonia albania greece occupies an important location between mediterranean and central european climate zones although previous multi proxy research on the late glacial to holocene sequence core co1215 320 cm ca 17 cal ka bp to present has demonstrated its great value as an archive of quaternary palaeoclimate data some uncertainty remains in the interpretation of climate change with the exception of oxygen stable isotope data previous palaeolimnological interpretation has relied largely on proxies for productivity here existing interpretation is strengthened by the addition of diatom data results demonstrate that shifts in diatom assemblage composition are driven primarily by lake level changes and thus permit more confident interpretation of shifts in moisture availability over time while corroborating previous interpretation of catchment and climate induced productivity shifts an inferred cold arid shallow lake phase between ca 17 1 and 15 7 cal ka bp is not only followed by a high productivity phase from ca 15 7 cal ka bp with late glacial warming but also is the first evidence for a gradual increase in lake level in line with other regional records clear evidence for a younger dryas climate reversal between ca 13 1 and 12 3 cal ka bp is followed by an unusually gradual transition to the holocene and deeper oligotrophic mesotrophic lake conditions are reached by ca 11 0 cal ka bp in contrast to the arid episode from ca 10 0 to 8 0 ka inferred from positive 18 ocalcite values rapid diatom inferred lake level increase after the start of the holocene suggests high moisture availability in line with palynological evidence but with only very subtle evidence for the impact of an 8 2 ka cold event the maintenance of high lake levels until 1 9 cal ka bp and the peak of inferred humidity from ca 7 9 to 6 0 cal ka bp matches the oxygen stable isotope profile and confirms that the latter is driven primarily by evaporative concentration rather than reflecting regional shifts in precipitation sources over time during the late holocene progressive eutrophication is inferred between 1 9 and present two shallow phases at ca 1 0 cal ka bp and at ca 100 years ago probably represent an aridity response which is added to increase human impact in the catchment overall the study is important in confirming previous tentative inferences that late glacial to holocene moisture availability has strong affinity with other sites in the eastern mediterranean it also tracks the pattern of north atlantic forcing

late pleistocene human occupation of the hyperarid core in the atacama desert northern chile abstract few archeological sites in south america contain uncontroversial evidence for when the first peopling of the continent occurred largely ignored in this debate extreme environments are assumed either as barriers to this early wave of migration or without potential for past habitability here we report on a rare 12 13 ka human occupation from quebrada mani site qm12 a plantless near rainless landscape 1240 m asl and 85 km from the pacific ocean located in the hyperarid core of the atacama desert this location harbored wetlands and riparian woodlands that were fed by increased rainfall further east in the central andes during the latest pleistocene excavations at qm12 yielded a diverse cultural assemblage of lithics burned and cut bones marine gastropods pigments plant fibers and wooden artifacts alongside a prepared fireplace sixteen radiocarbon dates from site qm12 on charcoal marine shells animal dung plant remains and wood reveal that the occupation took place between 12 8 and 11 7 ka these results demonstrate that the atacama desert was not a barrier to early american settlement and dispersal and provide new clues for understanding the cultural complexity and diversity of the peopling of south america during the last glacial interglacial transition

climate and environmental change in the balkans over the last 17 ka recorded in sediments from lake prespa albania f y r of macedonia greece this paper presents sedimentological geochemical and biological data from lake prespa albania former yugoslav republic of macedonia greece the 320 cm core sequence co1215 covers the last 17 ka calbp and reveals significant change in climate and environmental conditions on a local and regional scale the sediment record suggests typical stadial conditions from 17 1 to 15 7 ka calbp documented through low lake productivity well mixed conditions and cold resistant steppe catchment vegetation warming is indicated from 15 7 ka calbp with slightly increased in lake productivity gradual expansion of trees and decreasing erosion through disappearance of local ice caps between 14 5 and 11 5 ka calbp relatively stable hydrological conditions are documented the maximum in tree taxa percentages during the bolling allerod interstadial 14 5 13 2 ka calbp indicates increased temperatures and moisture availability whereas the increase of cold resistant open steppe vegetation taxa percentages during the younger dryas 13 2 11 5 ka calbp is coupled with distinct colder and drier conditions the holocene sequence from 11 5 ka calbp indicates ice free winters stratification of the water column a relatively high lake trophic level and dense vegetation cover over the catchment a strong climate related impact on the limnology and physical parameters in lake prespa is documented around 8 2 ka through a significant decrease in productivity enhanced mixing strong decomposition and soil erosion and a coeval expansion of herbs implying cool and dry climate conditions intensive human activity in the catchment is indicated from around 1 9 ka calbp this multiproxy approach improves our understanding of short and long term climate fluctuations in this area and their impact on catchment dynamics limnology hydrology and vegetation

first 36cl cosmogenic moraine geochronology of the dinaric mountain karst velež and crvanj mountains of bosnia and herzegovina abstract this article presents the first attempt to date moraines in the dinaric mountain karst using cosmogenic 36cl surface exposure dating technique twenty samples were collected from moraine boulders from two sets of the lowest and largest lateral moraines on the vele 1965 m asl and crvanj mountains 1920 m asl in bosnia and herzegovina the dated lateral terminal moraine complexes spanning elevations from 980 to 1350 m asl are up to 2 7 km long and rise more than 100 m above the valley floor the moraine boulders yielded 36cl ages spanning from oldest dryas for vele 14 9 1 1 ka to younger dryas for crvanj 11 9 0 9 ka considering the average age of the two oldest samples from each lateral moraine as the most representative time of moraine emplacement the dated moraines mark the largest extent of glaciers in both study areas which have been reconstructed to 28 km2 for vele and 24 km2 for crvanj having a mean equilibrium line altitude at 1388 m and 1541 m respectively under modern precipitation values which account for 2000 mm the temperature depression between 8 and 10 c is required to sustain the palaeoglaciers with reconstructed equilibrium line altitudes glaciers of similar size with such low equilibrium line altitudes during the lateglacial have not been reported until now for the balkan peninsula it is very likely that the boulder ages reflect complex exhumation and denudation histories which at this point do not allow obtaining more precise moraine chronologies for the study areas nevertheless this article delivers new data on the extent and timing of quaternary glaciations in the mediterranean mountains where records of glacier fluctuations seem to be asynchronous amongst different areas it is clear that dating moraines with cosmogenic 36cl surface exposure dating in carbonate lithologies in areas of high precipitation like the dinaric karst remains challenging

suppression of el nino during the mid holocene by changes in the earth s orbit a number of recent reports have interpreted paleoproxy data to describe the state of the tropical pacific especially changes in the behavior of the el nino southern oscillation enso over the holocene these interpretations are often contradictory especially for the eastern tropical pacific and adjacent areas of south america here we suggest a picture of the mid holocene tropical pacific region which reconciles the data enso variability was present throughout the holocene but underwent a steady increase from the mid holocene to the present in the mid holocene extreme warm el nino events were smaller in amplitude and occurred less frequently about a mean climate state with a cold eastern equatorial pacific and largely arid coastal regions as in the present climate this picture emerges from an experiment in which a simple numerical model of the coupled ocean atmosphere system in the tropical pacific was driven by orbital forcing we suggest that the observed behavior of the tropical pacific climate over the mid to late holocene is largely the response to orbitally driven changes in the seasonal cycle of solar radiation in the tropics which dominates extratropical influences

isotopic evolution of river water in the northern chile region two main northern chilean rivers the loa and tarapaca were investigated regarding their isotopic characteristics groundwater associated with various recharge zones and the input of tributaries along their courses mainly control their 180 2h isotopic composition of the rivers in the loa river carbon isotopic exchange between dissolved inorganic carbon dic and atmospheric coplays a minor role in the inorganic carbon cycle of the loa river the carbon isotopic composition 4 c 13 c of this river is probably controlled by carbon source associated with volcanic and geothermal activities and by the deposition of travertines for the tarapaca river the carbon isotope content of the dic reflects the input of recirculated water from irrigated areas along the river course and carbon isotopic exchange these findings imply that the input of volcanic and or geothermal co2 into the dic pool has to be evaluated in order to use carbon isotopes as a dating tool for groundwater in the loa basin and that modern conditions are not analogous to the paleohydrology of the tarapaca river

the glacial history of the dinaric alps montenegro abstract large areas of montenegro were glaciated during the pleistocene this paper presents evidence from the massifs of central montenegro including durmitor and sinjajevina moracke planine maganik prekornica and vojnik glacial deposits have been subdivided on the basis of morphostratigraphy and soil weathering and 31 u series ages from cemented tills provided a geochronological framework the largest glaciation occurred before 350 ka when a series of conjoined ice caps over the massifs of central montenegro covered a total area of nearly 1500 km 2 these formed during mis 12 and correspond with the largest skamnellian stage glaciations in greece to the south later middle pleistocene glaciations occurred during the penultimate glacial cycle correlating with the vlasian stage in greece mis 6 when ice caps covered an area of 720 km 2 over central montenegro there is also geochronological evidence of glacial deposits dating from the interval between mis 12 and mis 6 before the interglacial complex of mis 7 this glaciation appears to have been very similar in extent to that which occurred during mis 6 the last glacial cycle in central montenegro was characterised by valley and cirque glaciers covering a total area of 49 km 2 it is very likely that glaciers have been present in the mountains of central montenegro during every glacial cycle since a small glacier still survives today the smaller glaciers of the last glacial cycle are likely to have been associated with summer temperatures that were warmer than those of earlier cold stages the striking contrast in the extent and thickness of ice cover during the cold stages of the pleistocene has an important bearing on the geomorphological and biological evolution of the balkans

glaciation in the rila mountains bulgaria during the last glacial maximum abstract relict glacial landform complexes have been studied in the mountains of the central balkan peninsula since the end of the 19th century since their existence was proved for the first time by cvijic various authors have debated the number of glacial phases as well as their age at present the problem of age determination is being solved by the application of the new methods for numerical dating this paper is a detailed study of the maximum glaciation in the rila massif which is the highest mountain in bulgaria and in the whole balkan peninsula the application of cosmogenic nuclide dating 10be on moraine samples confirmed that the largest extent of former glaciers that left moraine deposits was around the time of the last glacial maximum most probably the maximum extent occurred in two phases the first around the beginning and the second around the end of the lgm 24 23 ka bp and 18 16 ka bp respectively separated by a retreat phase during the coldest but also driest phase of the glacial stage the gis processed calculations on the basis of field evidence of the former glacier extent and the preliminary calculations of the equilibrium line altitude ela through the accumulation ablation ratio aar method show that the ela during the lgm had quite small differences throughout the rila massif from about 2150 to 2200 m a s l in the nw to about 2250 2290 m in the se despite the considerable differences in terminal moraine depositional altitudes from 1150 to 2000 m a s l this is due to both the complicated pattern in the directions of moisture supply and to the influences of local topography

late glacial and holocene history of the northeast mediterranean mountain glaciers new insights from in situ produced 36cl based cosmic ray exposure dating of paleo glacier deposits on mount olympus greece in this study we present a new glacial chronology based on 20 in situ produced 36cl based cosmic ray exposure datings from moraine boulders and bedrock from the throne of zeus tz and megala kazania mk cirques on mount olympus the 36cl derived ages of glacial landforms range from 15 6 2 0 to 0 64 0 08 ka spanning the late glacial and the holocene the late glacial recorded in both cirques is partitioned in three distinct phases lg1 3 an initial phase of moraine stabilization at 15 5 2 0 ka with subsequent deglaciation starting at 14 ka lg1 followed by a shift to marginal conditions for glaciation at 13 5 2 0 ka lg2 sustained by large amounts of wind blown snow despite regional warming glacial conditions returned at 12 5 1 5 ka lg3 and were characterized by low air temperatures and glacier shrinking the holocene glacial phases hol1 3 are recorded only in the mk cirque likely due to its topographic attributes an early holocene glacier stillstand hol1 at 9 6 1 1 ka follows the regional temperatures recovery no glacier activity is observed during the mid holocene the late holocene glacier expansions include a moraine stabilization phase hol2 at 2 5 0 3 ka during wet conditions and solar insolation minima while hol3 corresponds to the early part of the little ice age 0 64 0 08ka our glacial chronology is coherent with glacial chronologies from several cirques along the northeast mediterranean mountains and in pace with numerous proxies from terrestrial and marine systems from the north aegean sea

prosopis sp tree ring oxygen and carbon isotope record of regional scale hydroclimate variability during the last 9500 years in the atacama desert abstract the hyper arid core of the atacama desert is one of the most persistently arid environments in the world yet there is evidence of significant hydroclimate variability during the holocene the timing of regional scale pluvial or humid periods has important implications for understanding the drivers of south american climate variability as well as the development of agriculture by prehistoric cultures here we present oxygen 18o and carbon 13c isotope values from ancient prosopis sp tree ring cellulose as a record relative humidity rh and water availability via intrinsic water use efficiency over century long intervals throughout the past 9 5 ka in the northern atacama desert 19 21 s these data provide the first high resolution ca annual evidence for decreasing water availability and increasing climate variability in the atacama from the early to late holocene intrinsic water use efficiency steadily increases over the holocene indicating a lowering of the water table and a reduction in the availability of groundwater resources in the region as water availability decreases 18o based estimates of rh show increased variance beginning 4 9 ka this change in rh coincides with the onset of modern day central andean atmospheric circulation patterns and previously documented humid periods in the southern altiplano 22 24 s subannual tree ring isotope analysis of modern and early holocene 8 3 ka trees show a similar seasonal cycle in carbon isotope values that correlates with modern annual changes in temperature however the early holocene interseasonal variability is greater than modern seasonality 18o values of the atacama tree rings are highly correlated with those of the sajama ice core from the bolivian andes demonstrating a teleconnection between high altitude andean precipitation and water availability in the atacama desert these reconstructions together provide a record of holocene water availability and ephemeral recharge related to changes in enso and south american monsoon

pleistocene ice caps on the coastal mountains of the adriatic sea ice caps once covered large areas of mount orjen 1894 m on the adriatic coast of montenegro bosnia herzegovina croatia the largest ice cap covered an area of c 165 km2 and reached a maximum ice thickness of c 450 m in some areas reaching down to 500 m above modern sea level u series dating of secondary carbonates within moraines indicates that the most extensive glaciation occurred during the middle pleistocene correlating with a major phase of glaciation in greece to the south during mis 12 c 480 430 ka later less extensive glaciations are also recorded in the cirques and valleys and correlate with glaciations during mis 6 190 130 ka and mis 5d 2 110 11 7 ka each phase of glaciation would have required large amounts of snow accumulation under modern precipitation values which at c 5000 mm are some of the highest in europe mean annual temperatures would need to be only c 5 6 c lower in order to form similar sized glaciers today a mean annual temperature depression of 12 13 c would still require 1000 mm of snow accumulation water equivalent to balance ablation suggesting sustained moisture supply during pleistocene cold stages such sustained precipitation supply during pleistocene cold stages is likely to have been facilitated by major temperature contrasts between the european landmass and the mediterranean sea which are likely to have sustained lee side vortices to the south of the alps in the gulf of genoa and adriatic sea forming weak moisture bearing depressions which tracked across the eastern adriatic coastal mountains large ice caps on the dinaric alps would have blocked the inland penetration of these depressions resulting in much drier conditions in the balkan interior creating favourable conditions for the deposition of thick accumulations of loess the last glaciers on orjen formed during the younger dryas 12 9 11 7 ka and confirm the influence of north atlantic ocean circulation on pleistocene climate change in this part of the mediterranean

reconstruction of late pleistocene glaciers on mount lovcen montenegro abstract the study of pleistocene glaciations in the dinaric alps began at the end of the 19th century since then the interpretation of glaciation in this area has not seen much study until the beginning of the 21st century when a few modern geomorphological studies with numerical dating and equilibrium line altitude ela reconstructions were carried out in the se part of the dinaric alps where mount lovcen is situated the morphology of mount lovcen consists of a karst landscape modified by glacial processes this paper presents geomorphological evidence of glaciations on mount lovcen along with a reconstruction of paleoglacier dimensions and estimations of the paleo equilibrium line altitude mapping of glacial landforms on mount lovcen revealed at least two different glacial events only limited patches of older glacial deposits were identified and therefore the reconstruction of glacier dimensions and ela were only performed for the younger glaciation this glacier extended over an area of at least 39 9 km 2 and reached a maximum thickness of about 290 m the regional ela for the mount lovcen glaciers was calculated as 1259 m

glaciers and rivers pleistocene uncoupling in a mediterranean mountain karst abstract large scale coupling between headwater catchments and downstream depocentres is a critical influence on long term fluvial system behaviour and on the creation of the fluvial sedimentary record however it is often difficult to examine this control over multiple quaternary glacial cycles and it has not been fully explored in karst basins by investigating the pleistocene glacial and fluvial records on and around mount orjen 1894 m in montenegro we show how the changing connectivity between glaciated mountain headwater source zones and downstream alluvial basins is a key feature of long term karst system behaviour especially in relation to the creation and preservation of the surface sedimentary record middle and late pleistocene glacial deposits are well preserved on mount orjen uranium series dating of 27 carbonate cements in fluvial sediments shows that many alluvial depocentres were completely filled with coarse glacial outwash before 350 ka during the largest recorded glaciation this major glaciation is correlated with the skamnellian stage in greece and marine isotope stage 12 mis 12 c 480 420 ka this was a period of profound landscape change in many glaciated catchments on the balkan peninsula later glaciations were much less extensive and sediment supply to fluvial systems was much diminished the extreme base level falls of the late miocene produced the world s deepest karst networks around the mediterranean after mis 12 the subterranean karst of mount orjen formed the dominant pathway for meltwater and sediment transfer so that the depositional basins below 1000 m became disconnected uncoupled from the glaciated headwaters there is little evidence of post mis 12 aggradation or incision in these basins this absence of later pleistocene and holocene fluvial activity means these basins contain some of the thickest and best preserved outwash deposits in the mediterranean

cosmogenic chlorine 36 from calcium spallation calcium is a major target element for cosmogenic 36cl production consequently 36cl rapidly reaches detectable levels in minerals such as calcite and calcium feldspar exposed at the earth s surface spallation of calcium isotopes typically accounts for 80 90 of 36cl production in these minerals with subsidiary contributions from negative muon capture by 40ca and thermal neutron capture by 35cl to provide a basis for surface exposure dating we have calibrated cosmogenic 36cl production in calcium feldspar from the 17 300 year old tabernacle hill basalt at an altitude of 1445 m and an effective geomagnetic latitude of 40 9 the calcium spallation rate is 152 11 atoms g ca 1 a 1 the corresponding rate at sea level and high latitude is estimated at 48 8 3 4 atoms g ca 1 a 1 the muon capture rate used to derive these values is 8 8 2 2 atoms g ca 1 a 1 at the tabernacle hill site scaled from a value of 4 8 1 2 atoms g ca 1 a 1 at sea level and high latitude the calcium spallation rate determined in this study is in excellent agreement with previous whole rock calibration measurements at tabernacle hill when these are recalculated with respect to the absolute timescale the calibration of 36c1 production from calcium underpins development of an exposure dating technique for calcite due to its high calcium content the 36cl production rate in calcite is higher than in any other common rock forming mineral measurement of 36cl in calcite with an accelerator mass spectrometric detection limit of 5 103 atoms per gram allows dating of limestone surfaces exposed for periods ranging from 102 106 years alternatively erosion rates from less than 1 to greater than 1000 m per year can be determined in the case of eroding karst surfaces though the 36cl production rate is lower in calcium feldspar than in calcite measurements on this mineral will provide a useful means of dating young basalt lavas