fluvial response to climate change during and after the last glacial maximum in central anatolia turkey abstract fluvial response to climate change during and after the last glacial maximum lgm included incision aggradation phases recorded in sediment cores from the valley floor of the kizilirmak in central anatolia a numerical chronology was established by ams dating of fluvial sediments and ar ar dating of a basalt sample capping the youngest terrace late pleistocene terrace indicating that the main incision phase was completed at the end of the lgm the succeeding aggradation phase in the valley took place from the end of the lgm onwards it appears that the major climatic transition from the lgm to the late glacial gave rise to aggradation in the fluvial system and this event seems to be consistent with the timing of the regression phase of pluvial lakes and the termination of paleoglacier advances in the high mountains of anatolia this study of fluvial systems in anatolia indicates that the coldest periods are not always characterized by fluvial aggradation

palaeo seasonality of the last two millennia reconstructed from the oxygen isotope composition of carbonates and diatom silica from nar golu central turkey carbonates and diatoms are rarely deposited together in lake sediments in sufficient quantities for the oxygen isotope composition 18o to be investigated simultaneously from both hosts here 18ocarbonate are compared to 18odiatom data from the varved sediments of nar golu a closed lake in central turkey over the last 1710 years lake monitoring suggests carbonate is probably precipitated during may june and 18ocarbonate is a proxy for regional water balance diatom activity is mainly weighted towards the spring at times between 301 and 561 ad while 18ocarbonate values are the highest for the entire 1710 year period suggesting summer drought 18ocorrected diatom values are among the lowest 18olakewater values estimated for the times of diatom growth and carbonate precipitation show large differences we suggest this could be explained by increased snowmelt that formed a freshwater lid on the lake at the time of peak diatom growth increased snowmelt is also inferred 561 801 ad from 801 ad to the present precipitation is less winter dominated although increased snowmelt is inferred 921 1071 ad and in the latter part of the little ice age i e the mid to late 1800s ad by combining oxygen isotope data from hosts that form in lakes at different times of the year we show that such analyses can provide insights into palaeo seasonality

late glacial to mid holocene palaeoclimate development of southern greece inferred from the sediment sequence of lake stymphalia ne peloponnese abstract the sedimentary sequence of lake stymphalia ne peloponnese for the first time sheds light on the palaeoclimate development of southern greece from 15 to 5 ka bp new geochemical data based on high resolution x ray fluorescence scanning provide in situ and continuous analysis of predefined element suites on split core surfaces variations of elements over time were assessed constructing correlation matrices based on the calculation of pearson correlation coefficients the element suite includes al si k ca ti mn fe zn rb sr and zr a major result includes that changes in element behaviour are related to hydrological changes in the catchment precipitation lake level status and evaporation insolation solar activity and are ultimately driven by climate major trends shifts in elemental ratios correspond to the climate development in the eastern mediterranean region based on correlation of rb sr reflecting wet dry climates with foraminiferal proxies of marine core lc21 from the southern aegean sea and the stable oxygen isotope record of soreq cave israel the bolling allerod the younger dryas and the 8 2 ka cold event were identified

itrax description and evaluation of a new multi function x ray core scanner a new automated multi function core scanning instrument named itrax has been developed that records optical radiographic and elemental variations from sediment half cores up to 1 8 m long at a resolution as fine as 200 m an intense micro x ray beam focused through a flat capillary waveguide is used to irradiate samples to enable both x radiography and x ray fluorescence xrf analysis data are acquired incrementally by advancing a split core via a programmable stepped motor drive through the flat rectangular section x ray beam traditional xrf determination of element composition in sediments provides high quality data but it takes a considerable time and normally consumes gram quantities of material that is often only available in limited quantities the itrax core scanner non destructively collects optical and x radiographic images and provides high resolution elemental profiles that are invaluable for guiding sample selection for further destructive detailed sampling this paper presents a description of the construction characteristics and capabilities of the itrax system high resolution itrax data obtained from sediment cores are also presented and compared with results from traditional wavelength dispersive xrf analysis at lower resolution finally some recent technical developments linked to the second generation itrax are presented

mid to late holocene flood frequency changes in the northeastern alps as recorded in varved sediments of lake mondsee upper austria abstract annually laminated varved lake sediments with intercalated detrital layers resulting from sedimentary input by runoff events are ideal archives to establish precisely dated records of past extreme runoff events in this study the mid to late holocene varved sediments of lake mondsee upper austria were analysed by combining sedimentological geophysical and geochemical methods this approach allows to distinguish two types of detrital layers related to different types of extreme runoff events floods and debris flows and to detect changes in flood activity during the last 7100 years in total 271 flood and 47 debris flow layers deposited during spring and summer were identified which cluster in 18 main flood episodes fe 1 18 with durations of 30 50 years each these main flood periods occurred during the neolithic 7100 7050 vyr bp and 6470 4450 vyr bp the late bronze age and the early iron age 3300 3250 and 2800 2750 vyr bp the late iron age 2050 2000 vyr bp throughout the dark ages cold period 1500 1200 vyr bp and at the end of the medieval warm period and the little ice age 810 430 vyr bp summer flood episodes in lake mondsee are generally more abundant during the last 1500 years often coinciding with major advances of alpine glaciers prior to 1500 vyr bp spring summer floods and debris flows are generally less frequent indicating a lower number of intense rainfall events that triggered erosion in comparison with the increase of late holocene flood activity in western and northwestern nw europe commencing already as early as 2800 yr bp the hydro meteorological shift in the lake mondsee region occurred much later these time lags in the onset of increased hydrological activity might be either due to regional differences in atmospheric circulation pattern or to the sensitivity of the individual flood archives the lake mondsee sediments represent the first precisely dated and several millennia long summer flood record for the northeastern ne alps a key region at the climatic boundary of atlantic mediterranean and east european air masses aiding a better understanding of regional and seasonal peculiarities of flood occurrence under changing climate conditions

prehistoric debris avalanches from mount cayley volcano british columbia reply an investigation of diamicton units exposed in an extensive accumulation of volcanic debris in the squamish valley west of mount cayley volcano has yielded evidence for at least three major debris avalanches initiated by the collapse of the western flank of mount cayley in the mid holocene radiocarbon ages obtained from tree fragments contained in the deposits indicate that the events took place at 4800 1100 and 500 bp all three debris avalanches dammed the squamish river and formed temporary lakes upstream of the debris failure of the cone took place after considerable dissection of the original edifice had exposed weak pyroclastic materials at the base of the steep upper slope of the volcano no evidence of older debris avalanches from mount cayley has been discovered smaller scale debris avalanches probably have been common and at least two have occurred in historic time 1963 and 1984 debris avalanches from mount cayley and the effects of a possible damming of the squamish river are major

holocene environmental change and its impact on sediment dynamics in the eastern mediterranean abstract investigators have studied past environmental change in the eastern mediterranean region from a number of perspectives while climate reconstructions and palynological research have focused on forces that drive the geomorphologic system many researchers have attempted to use sediment archive studies to identify periods of change in sediment dynamics due to the large variability in environmental parameters and the variety of landscapes present in the eastern mediterranean region research has focused on sediment archives ranging from small colluvial sites to deltas of large rivers on the mediterranean coast as the cultural record for the region is extremely rich the main goal of palaeo environmental research in the eastern mediterranean has been to identify the relative importance of human impact on the landscape nevertheless sediment archives have significant limitations chronological control for many palaeo environmental records is highly uncertain and rates of landscape change are oftentimes difficult to assess most palaeo environmental research has been conducted on or near archeological sites where direct human impact may obscure the indirect impact on sediment dynamics through land use changes quantification and modeling of sediment dynamics in the eastern mediterranean environment offer one solution when erosion and sediment transport rate analyses are incorporated periods of relatively important change can be identified using multiple approaches the relative importance of the main driving forces climate and land use become distinguishable since field based data from the actual sediment archives remain vital an overview of numerous studies in the eastern mediterranean is provided in order to draw a general picture for different time periods and the relative scale of regional landscape development during the holocene a comparison of sediment dynamics with the record of driving forces indicates that while climate was the main driver of the geomorphic system during the early holocene at some point human impact became widespread and began to dictate sediment dynamics to a large extent from the byzantine period onward soil properties seem to play an increasingly important role as the hillslope soil reservoir in the eastern mediterranean was progressively depleted during the late holocene

cause and effect in mediterranean erosion the role of humans and climate upon holocene sediment flux into a central anatolian lake catchment abstract the debate in historical geomorphological studies about the causes of erosion in regions such as the mediterranean has been long standing the relative roles of climate change and human impacts can be difficult to disentangle in the absence of highly resolved chronologies here we reconstruct the erosion history of a small lake catchment in central anatolia located on the edge of one of the mediterranean s most iconic badland landscapes in cappadocia because these lake sediments are annually laminated precisely dating clastic inwash layers and calculating recurrence intervals and flux rates is possible lake cores have been analysed for xrf elemental geochemistry and via thin sections along with proxies for hydroclimate oxygen isotopes and land cover pollen peaks in titanium along with other detrital elements and changes in clastic layers indicate increased sediment influx into nar lake between 9300 and 8000 cal bp ceramic neolithic when obsidian mining took place nearby and again more importantly during the last 2500 years iron age to modern the latter exhibiting three phases of enhanced catchment erosion multiproxy comparisons show that these phases were related primarily to periods of increased human impact on vegetation and soils around the lake most sediment influx has been in the form of turbidites linked to the presence of a fan delta at the lake edge although this store does not appear to have significantly delayed sediment delivery from eroding hillslopes to the lake bed the marked increase in detrital influx during the late holocene implies that badland development in the lake catchment is recent and largely anthropogenic rather than ancient and of climatic causation and probably involving stream capture the record also shows that sediment influx diminished markedly at times when human land use disintensified which in turn indicates that hillslope degradation is reversible with appropriate land management

impregnation method for detecting annual laminations in sediment cores an overview abstract annually laminated sediments can provide an absolute time scale by varve counting and a high resolution palaeoclimate information from varve thickness both types of information may be directly measured from sediment core surfaces in this paper we stress that varve counting and varve thickness measurements derived from fresh core surfaces could not systematically reveal the internal sedimentary structure even if assisted by high resolution image analysis we present an example of a homogeneous sediment core for which the varves were only observable after core impregnation and polishing steps because the impregnation methods are not yet standardized the aim of this paper is to give an updated review of the methodology in this review we present the major critical points during impregnation steps in particular we focus on all of the post treatment sediment disturbances that can alter the laminated micro structure and consequently varve measurements finally we propose a modified impregnation protocol especially adapted for tracking varved intervals in long cores

eastern mediterranean hydroclimate over the late glacial and holocene reconstructed from the sediments of nar lake central turkey using stable isotopes and carbonate mineralogy there is a lack of high resolution records of hydroclimate variability in the eastern mediterranean from the late glacial and early holocene more knowledge of the speed of climate shifts and the degree to which they were synchronous with changes in the north atlantic or elsewhere is required to understand better the controls on eastern mediterranean climate using endogenic carbonate from a sediment sequence from nar golu a maar lake in central turkey dated by varve counting and uranium thorium methods we present high resolution 25 years oxygen 18o and carbon isotope records supported by carbonate mineralogy data spanning the late glacial and holocene 18ocarbonate at nar golu has been shown previously to be a strong proxy for regional water balance after a dry period i e evaporation far exceeding precipitation in the younger dryas the data show a transition into the relatively wetter early holocene in the early holocene there are two drier periods that appear to peak at 9 3 ka and 8 2 ka coincident with cooling events seen in north atlantic records after this and as seen in other records from the eastern mediterranean there is a millennial scale drying trend through the mid holocene transition the relatively dry late holocene is punctuated by centennial scale drought intervals at the times of 4 2 ka event and late bronze age societal collapse overall we show that central turkey is drier when the north atlantic is cooler throughout this record and at multiple timescales thought to be due to a weakening of the westerly storm track resulting from reduced cyclogenesis in the north atlantic however some features such as the mid holocene transition and the fact the early holocene dry episodes at nar golu are of a longer duration than the more discrete events seen in north atlantic records imply there are additional controls on eastern mediterranean hydroclimate

a pleistocene pyroclastic poor maar from central anatolia turkey influence of a local fault on a phreatomagmatic eruption in central anatolia the late pleistocene narkoy maar formed on a fault zone a 5 m thick pyroclastic succession erupted from a crater 900 m in diameter the presence of gas fumeroles hot springs and hydrothermal alteration zones indicates that the area is geothermally active the products of the maar are large blocks and lapilli to coarse ash planar bedding and cross stratification are well developed within coarse ash beds the maar deposits were generated by a single period of phreatomagmatic explosion with two episodes the first episode produced wet eruption clouds while the second one was relatively dry in nature the estimate of the volume of pyroclastic ejecta compared with the dimensions of the maar demonstrates a material deficiency which is attributed to a large volume of gas emanated during the phreatomagmatic explosion along a fault presently cross cutting the maar in addition a relatively small volume of magma intruded along the fault and mixed with meteoric water in the fault zone to produce the phreatomagmatic eruption the existence of a hydrothermal system in the fault zone is important in affecting the eruption style and evolution of narkoy maar

sensitivity of the eastern mediterranean geomorphic system towards environmental change during the late holocene a chronological perspective alluvial and colluvial sediment deposition provide a vital record of environmental change during the holocene firm chronological control on these archives is necessary to enable us to relate sediment dynamics to human activity and climate variability in the eastern mediterranean such relationships are hard to establish due to the lack of spatially well distributed sediment archives with good chronological control this scarcity is problematic with respect to regional scale reconstructions of the temporal variation of sediment dynamics here we present a radiocarbon database n 178 of geomorphological activity collected from multiple distinct sediment archives within the territory of sagalassos in south western turkey the data were grouped according to their sedimentary facies for analysis using cumulative probability distributions cpds and sedimentation rate sr modelling two small scale colluvial valleys where chronological information was abundant were investigated in more detail results show that sedimentation chronology differs between individual nearby cores as it depends strongly on the local geomorphic situation a generalizing approach combining multiple core results yields more widely valid conclusions high sedimentation rates coincided with the initial major anthropogenic disturbance of the landscape and decreased afterwards probably due to hillslope soil depletion cpd and sr analysis indicates that in general colluvial sedimentation rates did not change much from 2000 bc onwards river floodplain sedimentation in contrast increased markedly during the first millennium bc and during recent times and a significant time lag in enhanced sediment deposition between the upper and lower reaches of the river valleys was observed copyright 2012 john wiley sons ltd

the geomorphology of the anthropocene emergence status and implications the anthropocene is proposed as a new interval of geological time in which human influence on earth and its geological record dominates over natural processes a major challenge in demarcating the anthropocene is that the balance between human influenced and natural processes varies over spatial and temporal scales owing to the inherent variability of both human activities as associated with culture and modes of development and natural drivers e g tectonic activity and sea level variation against this backdrop we consider how geomorphology might contribute towards the anthropocene debate focussing on human impact on aeolian fluvial cryospheric and coastal process domains and how evidence of this impact is preserved in landforms and sedimentary records we also consider the evidence for an explicitly anthropogenic geomorphology that includes artificial slopes and other human created landforms this provides the basis for discussing the theoretical and practical contributions that geomorphology can make to defining an anthropocene stratigraphy it is clear that the relevance of the anthropocene concept varies considerably amongst different branches of geomorphology depending on the history of human actions in different process domains for example evidence of human dominance is more widespread in fluvial and coastal records than in aeolian and cryospheric records so geomorphologically the anthropocene would inevitably comprise a highly diachronous lower boundary even to identify this lower boundary research would need to focus on the disambiguation of human effects on geomorphological and sedimentological signatures this would require robust data derived from a combination of modelling and new empirical work rather than an arbitrary war of possible boundaries associated with convenient but disputed golden spikes rather than being drawn into stratigraphical debates the primary concern of geomorphology should be with the investigation of processes and landform development so providing the underpinning science for the study of this time of critical geological transition

a high resolution late holocene lake isotope record from turkey and links to north atlantic and monsoon climate a high resolution proxy record of precipitation and evaporation variability through the past 1700 yr from 18o analysis of a varved lake sequence from central turkey shows rapid shifts between dry periods ad 300 500 and ad 1400 1950 and wetter intervals ad 560 750 and ad 1000 1350 changes are consistent with changes in instrumental and proxy records of the indian monsoon dry summers in the eastern mediterranean being associated with periods of enhanced monsoon rainfall in addition major shifts in the record are coherent with changes in north atlantic winter climate with cold wet periods in the alps occurring at times of dry turkish climate

landscape patterns of vegetation change indicated by soil carbon isotope composition vegetation change particularly from the grass to shrub life form is a critical issue on the world s semiarid rangelands stable carbon isotope y 13 c values and associated radiocarbon ages from soil organic matter som were used to evaluate vegetation change across five landscape positions at a small enclosed basin in southeastern arizona light and dense som fractions were separated to distinguish recent vegetation changes the direction and timing of vegetation change differed with landscape position along a gentle elevation gradient from the basin outlet to a nearby volcanic ridge top c4 perennial grasses have dominated the basin outlet center and toe slope landscape positions since at least 5000 6000 years bp except for the dominance of c3 plants at the bottom of the outlet excavation at 5000 years bp this isotopic change is associated with rounded cobbles that may have been a stream channel suggesting the presence of c3 herbaceous or woody riparian vegetation on midslope and ridge top landscape positions where semidesert shrubs now dominate the proportion of plants with c4 metabolism calculated from mass balance mixing formulas decreased from approximately 60 as recently as 400 years bp to only 1 5 observed today the light som fraction from mid slope and ridge top surface soil horizons was approximately 30 c4 and had a post bomb date suggesting that the conversion from grass to shrub occurred over the last several decades d 2003 elsevier b v all rights reserved

historical landscape change in cappadocia central turkey a palaeoecological investigation of annually laminated sediments from nar lake coupled multiproxy indicators pollen stable isotopes and charcoal reconstructed from annually laminated lake sediments from nar ga la in cappadocia central turkey complemented by documentary and archaeological evidence provide a detailed record of environmental changes and their causes from late antiquity ad 300 to the present day stable isotope data indicate marked shifts in the variability in summer drought intensity and winter spring rainfall but these did not coincide in time with changes in vegetation and land use shown by pollen data rather human impacts appear to have been the main driver of landscape ecological changes in cappadocia over the last two millennia pollen and charcoal data indicate four principal land use phases i an early byzantine agrarian landscape characterized by cereals and tree crops and marking the later part of the so called beya ehir occupation phase ii a period of landscape abandonment and the establishment of secondary woodland from ad 670 to 950 coinc

characteristics of sedimentary varve chronologies a review abstract we constructed a varve data base vdb to study the worldwide distribution of varved sediment records and the fidelity of their varve chronologies clusters of lakes with varved sediments exist in central north america in the canadian arctic and in northern and central europe among the 108 sites included in the vdb varved records are typically 200 500 cm long and cover a period of 1000 2000 years their varve chronologies are often based on counting of annual layers from fresh sediment surfaces and photographs or from epoxy embedded sediment blocks and thin sections the vdb indicates that chronological errors associated with counting sedimentary varves fall generally between 1 and 3 but only 57 of published records are providing quantitative error estimations for their chronologies with a careful documentation of varves and by applying radiometric dating methods to surface sediments as well as using historical events as time markers there is the potential of having centennial long varved records with a very precise age depth control however it is unrealistic to expect errors significantly below 1 from several millennia long sections we found no indication that varve chronologies would have been substantially more accurate and precise in some parts of the world than in others or statistically dependent on varve thickness or temporal extension of a varved sequence according to the vdb close to 90 of the published varve chronologies have been cross checked with some independent dating methods

tephrostratigraphy chronology and climatic events of the mediterranean basin during the holocene an overview the identification and characterisation of high frequency climatic changes during the holocene requires natural archives with precise and accurate chronological control which is usually difficult to achieve using only 14c chronologies the presence of time spaced tephra beds in quaternary mediterranean successions represents an additional independent tool for dating and correlating different sedimentary archives these tephra layers are potentially useful for resolving long standing issues in paleoclimatology and can help towards correlating terrestrial and marine paleoclimate archives known major tephras of regional extent derive from central and southern italy the hellenic arc and from anatolia a striking feature of major holocene tephra deposition events in the mediterranean is that they are clustered rather than randomly distributed in time several tephra layers occurred at the time of the s1 sapropel formation between c 8 4 and 9 0 ka bp mercato gabellotto fiumebianco e1 cappadocia and ot

mediterranean valleys revisited linking soil erosion land use and climate variability in the northern levant abstract this paper presents results of geomorphological and archaeological investigations undertaken in several small drainage basins in the jebel al aqra region of southern turkey by focusing intensive archaeological settlement survey in basins where securely dated sequences of sedimentary valley fills have been recorded spatially and temporally linked high resolution records of land use and soil erosion have been generated sedimentary data show that throughout most of the holocene floodplains remained rather stable allowing deep soils to form but in the past two millennia probably from ad 150 700 a phase of severe soil erosion was initiated and resulted in the deposition of 3 5 5 0 m of alluvial sediments on valley floors archaeological and historical evidence suggest that while these areas were occupied by agrarian communities since at least 2800 bc nearly three millennia of cultivation during the bronze and iron ages had relatively little effect on soil erosion the intensification of settlement throughout the region and the conversion of upland areas to intensive agricultural production during the hellenistic roman and late roman periods 300 bc ad 650 however created the necessary preconditions for severe soil erosion to occur these data are compared against modern and paleoclimate studies of the eastern mediterranean which show an extremely variable precipitation regime and the effects that it can have on erosion a 400 year lag between the initial settlement of upland areas and the first evidence of soil erosion suggest that it may have been the intersection of extreme precipitation events with particular land use conditions of the roman and late roman periods which worked together to drive soil erosion

holocene environmental change in southwest turkey a palaeoecological record of lake and catchment related changes percentage concentration and accumulation pollen data together with diatom and non siliceous microfossil data are presented for the site of go lhisar go l u 37i8 n 29i36 e elevation 930 m a small intramontane lake in burdur province southwest turkey microfossil assemblages from the longest sediment core gha 813 cm record changes in local and regional vegetation and lake productivity over the last 9500 years pollen spectra indicate that vegetation progressed from an open landscape with an increase in arboreal pollen occurring 8500 bp to mixed forest comprising oak pine and juniper until around 3000 bp cal 1240 bc when a human occupation phase becomes discernible from the pollen spectra this occurs shortly after the deposition of a volcanic tephra layer which originated from the minoan eruption of santorini thera and radiocarbon dated to 3330 70 yr bp cal 1600 bc this human occupation phase is comparable to the beys ehir occupation phase recorded at other sites in southwest turkey and involved forest clearance and the cultivation of fruit trees such as olea juglans castanea and itis together with arable cereal growing and pastoralism the presence of pollen types associated with the beys ehir occupation phase in deposits above the santorini tephra layer confirms a late bronze age early anatolian dark age date for its commencement since 3000 bp notable changes in aquatic ecology associated with tephra deposition and subsequent nutrient and sediment flux from the lake catchment are recorded the beys ehir occupation phase at go lhisar go l u came to an end around 1300 bp cla ad 700 when pine appears to have become the dominant forest tree 1999 elsevier science ltd all rights reserved

new techniques in sediment core analysis an introduction marine sediment cores are the fundamental data source for information on seabed character depositional history and environmental change they provide raw data for a wide range of research including studies of global climate change palaeoceanography slope stability oil exploration pollution assessment and control and sea floor surveys for laying cables pipelines and siting of sea floor structures during the last three decades a varied suite of new technologies have been developed to analyse cores often non destructively to produce high quality closely spaced co located downcore measurements characterizing sediment physical properties geochemistry and composition in unprecedented detail distributions of a variety of palaeoenvironmentally significant proxies can now be logged at decadal and in some cases even annual or subannual scales allowing detailed insights into the history of climate and associated environmental change these advances have had a profound effect on many aspects of the earth sciences particularly palaeoceanography in this paper we review recent advances in analytical and logging technology and their application to the analysis of sediment cores developments in providing access to core data and associated datasets and data mining technology in order to integrate and interpret new and legacy datasets within the wider context of sea floor studies are also discussed despite the great advances in this field however challenges remain particularly in the development of standard measurement and calibration methodologies and in the development of data analysis methods new data visualization tools and techniques need to be developed to optimize the interpretation process and maximize scientific value amplified collaboration environments and tools are needed in order to capitalize on our analysis and interpretation capability of large multi parameter datasets sophisticated yet simple to use searchable internet databases with universal access and secure long term funding and data products resulting in user defined data mining query and display so far pioneered in the usa and australia provide robust models for efficient and effective core data stewardship

tracking the hydro climatic signal from lake to sediment a field study from central turkey palaeo hydrological interpretations of lake sediment proxies can benefit from a robust understanding of the modern lake environment in this study we use nar golu a non outlet monomictic maar lake in central turkey as a field site for a natural experiment using observations and measurements over a 17 year monitoring period 1997 2014 we compare lake water and sediment trap data to isotopic chemical and biotic proxies preserved in its varved sediments nar golu underwent a 3 m lake level fall between 2000 and 2010 18olakewater is correlated with this lake level fall responding to the change in water balance endogenic carbonate is shown to precipitate in isotopic equilibrium with lake water and there is a strong relationship between 18olakewater and 18ocarbonate which suggests the water balance signal is accurately recorded in the sediment isotope record over the same period sedimentary diatom assemblages also responded and conductivity inferred from diatoms showed a rise shifts in carbonate mineralogy and elemental chemistry in the sediment record through this decade were also recorded intra annual changes in 18olakewater and lake water chemistry are used to demonstrate the seasonal variability of the system and the influence this may have on the interpretation of 18ocarbonate we use these relationships to help interpret the sedimentary record of changing lake hydrology over the last 1725 years nar golu has provided an opportunity to test critically the chain of connection from present to past and its sedimentary record offers an archive of decadal to centennial scale hydro climatic change

late quaternary mass movement events in lake el gygytgyn north eastern siberia lake el gygytgyn is situated in a 3ae6 myr old impact crater in north eastern siberia its sedimentary record probably represents the most complete archive of pliocene and quaternary climate change in the terrestrial arctic in order to investigate the influence of gravitational sediment transport on the pelagic sediment record in the lake centre two sediment cores were recovered from the lower western lake slope the cores penetrate a sub recent mass movement deposit that was identified by 3ae5 khz echo sounding in the proximal part of this deposit deformed sediments reflect an initial debris flow characterized by limited sediment mixture above and in front of the debrite a wide massive densite indicates a second stage with a liquefied dense flow the mass movement event led to basal erosion of ca 1 m thick unconsolidated sediments along parts of its flow path the event produced a suspension cloud whose deposition led to the formation of a turbidite the occurrence of the turbidite throughout the lake and the limited erosion at its base mainly suggest deposition by pelagic rain following stokes law very similar radiocarbon dates obtained in the sediments directly beneath and above the turbidite in the central lake confirm this interpretation when applying the depositional model for the late quaternary sediment record of lake el gygytgyn the recovered turbidites allow reconstruction of the frequency and temporal distribution of large mass movement events at the lake slopes in total 28 turbidites and related deposits were identified in two 12ae9 and 16ae6 m long sediment cores from the central lake area covering approximately 300 kyr

climate controlled river terrace formation in the kizilirmak valley cappadocia section turkey inferred from ar ar dating of quaternary basalts and terraces stratigraphy abstract this study was carried out on the cappadocia section of the kizilirmak river valley the longest river completely within the borders of turkey 1355 km a staircase of fifteen terraces found in the valley is maintained against erosion at elevations up to 160 m above the current river level the gulsehir karaburna quatenary basalts four basalt flows which cap four terraces were numerically dated for the first time using the ar ar technique the evren ridge basalt 1 160 m above the river level and capping terrace 1 was dated to 1989 4 38 9 ka the karaburna basalt plateau 2 is 128 m above the river level and caps terrace 4 and was dated to 1228 2 46 4 ka the tuzkoy basalt plateau 3 29 m above the river level and capping terrace 12 was dated to 403 8 9 8 ka and the karniyarik hill basalts 4 at 4 5 m above the river level and capping terrace 15 were dated to 96 0 13 0 ka these basalt ages provide minimum ages for the underlying fluvial deposits on the one hand these data show that kizilirmak river incised its valley by 160 m during the last 2 ma of its evolution on the other hand by using terrace sequences and basalt ages the time averaged incision rate of the river during the last 2 ma was determined as approximately 0 08 mm a 1 but important variations within that time span are also apparent the highest incision rate during this period was determined to be 0 12 mm a 1 between the late early and mid middle pleistocene from the numerical chronology terrace stratigraphy and paleosol records it is suggested that the main incision phases of the kizilirmak river led to terrace formation during the cold periods and the deposition phases occurred during the warm periods including cold warm transitions as a result of assigning terraces to marine oxygen isotope stages it was inferred that nearly all terrace levels had formed during the eccentricity driven climate cycles in association with high uplift rates which were interpreted as being complete in the valley

high resolution x ray fluorescence core scanning analysis of les echets france sedimentary sequence new insights from chemical proxies the les echets sediment sequence has recently been the subject of a high resolution multi proxy study which revealed shifts in lake productivity linked to greenland stadials and interstadials over the last 40 ka wohlfarth et al 2008 rapid ecosystem response to abrupt climate changes during the last glacial period in western europe 40 16 ka geology 36 407 410 here we present new elemental data for this sequence as acquired using an x ray fluorescence core scanning system which provides in situ high resolution continuous multi element analyses it was found that the strength of associations between the studied elements ti rb k zr si ca sr mn and fe varied over time with changes in lake status which are ultimately driven by changes in climate increases in fine grained detrital input as indicated by ti rb k and zr rb overlap with independently established periods of lower lake productivity and are interpreted to represent more arid conditions several of these arid periods are coincident with low diatom concentrations and the timing of heinrich events h4 h3 and h2 the duration of the environmental impacts linked to the h events varied by proxy with elemental data ti and zr rb estimating shorter events than the diatom data periods of lower detrital input and coarser grain sizes agreed in time with periods of higher lake productivity the elemental data provide new insights into hydrological changes and related sediment processes within the catchment and highlight the need for multi element and multi proxy approaches when reconstructing climate change using lacustrine sediment sequences copyright 2011 john wiley sons ltd