weak monsoon event at 4 2 ka recorded in sediment from lake rara himalayas abstract the strength of the indian summer monsoon varied significantly on centennial to millennial timescales during the holocene among these variations a weak summer monsoon event occurred approximately at 4 ka the so called 4 2 ka event this event is considered to have been a relatively sustained and widespread phenomenon at regional scales across southern asia to eastern africa however little is known about the impact of such variations in the himalayas a key location for understanding the monsoon system here we present a record of changes in summer monsoon strength during the holocene from lake rara western nepal using redox sensitive elements mn ti and mn fe measured by x ray fluorescence xrf core scanner in addition organic matter properties toc 13c and c n and changes in the 14c age offset between bulk organic matter and leaf matter namely the old carbon offset are used to augment the environmental reconstruction collectively the data indicate a period of prolonged weak monsoon interval at around 4 ka the timing of onset and recovery from the event observed at lake rara exhibits particular similarity with changes in the indus river discharge this is the first record of the 4 2 ka event from the himalayas based on a relatively well constructed age model using 14c dates that are not influenced by reservoir effects these findings provide an important step towards better understanding the spatial and temporal variability in the holocene indian monsoon

holocene climate variations from zhuyeze terminal lake records in east asian monsoon margin in arid northern china zhuyeze palaeolake is a terminal lake situated in the arid northern china in the east asian monsoon margin in order to examine the holocene palaeoclimatic change in the east asian monsoon margin qingtu lake section qtl from zhuyeze palaeolake is sampled in high resolution palaeoclimatic proxies such as grain size carbonate toc c n and delta 13 c of organic matter were analyzed eleven 14 c samples and six optically stimulated luminescence osl samples were dated to provide chronological control we also investigated the geomorphic features of lake shorelines in this area the results show that the climate was warm and dry in early holocene 9 5 7 0 cal ka bp cool and humid in mid holocene 7 0 4 8 cal ka bp and increasingly drier in late holocene since 4 8 cal ka bp comparisons of our records with other records in adjacent areas as well as with the records in the asian monsoon areas suggested that changes in effective moisture was synchronous in east asian monsoon marginal zone i e the pattern of dry early holocene humid mid holocene and aridity increasing late holocene and that the moisture optimum during the holocene was out of phase between asian monsoon margin and asian monsoonal dominated region possibly due to the high temperature at that time c 2010 university of washington published by elsevier inc all rights reserved zhuyeze palaeolake is a terminal lake situated in the arid northern china in the east asian monsoon margin in order to examine the holocene palaeoclimatic change in the east asian monsoon margin qingtu lake section qtl from zhuyeze palaeolake is sampled in high resolution palaeoclimatic proxies such as grain size carbonate toc c n and delta 13 c of organic matter were analyzed eleven 14 c samples and six optically stimulated luminescence osl samples were dated to provide chronological control we also investigated the geomorphic features of lake shorelines in this area the results show that the climate was warm and dry in early holocene 9 5 7 0 cal ka bp cool and humid in mid holocene 7 0 4 8 cal ka bp and increasingly drier in late holocene since 4 8 cal ka bp comparisons of our records with other records in adjacent areas as well as with the records in the asian monsoon areas suggested that changes in effective moisture was synchronous in east asian monsoon marginal zone i e the pattern of dry early holocene humid mid holocene and aridity increasing late holocene and that the moisture optimum during the holocene was out of phase between asian monsoon margin and asian monsoonal dominated region possibly due to the high temperature at that time c 2010 university of washington published by elsevier inc all rights reserved

persistent solar influence on north atlantic climate during the holocene surface winds and surface ocean hydrography in the subpolar north atlantic appear to have been influenced by variations in solar output through the entire holocene the evidence comes from a close correlation between inferred changes in production rates of the cosmogenic nuclides carbon 14 and beryllium 10 and centennial to millennial time scale changes in proxies of drift ice measured in deep sea sediment cores a solar forcing mechanism therefore may underlie at least the holocene segment of the north atlantic9s 1500 year cycle the surface hydrographic changes may have affected production of north atlantic deep water potentially providing an additional mechanism for amplifying the solar signals and transmitting them globally

contrasting patterns of early twenty first century glacier mass change in the himalayas glaciers are among the best terrestrial climate indicators an important water resource in mountains1 2 and a major contributor to global sea level rise3 4 in the hindu kush karakoram himalaya region hkkh a paucity of appropriate glacier data has prevented a comprehensive assessment of current regional mass balance5 however there are indirect evidences of a complex pattern of glacial responses5 8 in reaction to heterogeneous climate change signals9 here we provide the first coherent data set of detailed glacier thickness changes over the hkkh during 2003 2009 by combining satellite laser altimetry and a global elevation model in the eastern central and south western parts of the hkkh glacier wastage is widespread with regional thinning rates up to 0 66 0 09 m a 1 in the jammu kashmir region conversely in the karakoram glaciers are close to balance with only a slight thinning of 0 07 0 04 m a 1 regionally averaged thinning rates under debris mantled ice are similar to those of clean ice despite insulation by debris covers the 2003 2008 specific mass balance for our hkkh study region is 0 21 0 05 m a 1 water equivalent we significantly less negative than the global average of 0 7 m a 1 we for glaciers and ice caps4 10 this difference is mainly an effect of the balanced glacier mass budget in the karakoram the corresponding hkkh sea level contribution is 0 035 0 009 mm a 1 amounting to 1 of the present day sea level rise11 our 2003 2008 mass budget of 12 8 3 5 gt a 1 is more negative than recent satellite gravimetry based estimates of 5 6 gt a 1 over 2003 2010 ref 12 for the mountain catchments of the indus and ganges basins13 the glacier imbalance contributes 3 5 and 2 0 respectively to the annual average river discharge13 and up to 10 for the upper indus basin14

lake qinghai sediment geochemistry linked to hydroclimate variability since the last glacial abstract geochemistry of basin sediments from semi arid regions is valuable to understand past hydroclimatic changes here we investigate the links of sedimentary geochemistry rb sr ca zr toc and caco 3 carbonate mineralogy and ostracod shell 18 o of lake qinghai a basin proximal to major dust production centers at mid latitudes of the northern hemisphere to changes in depositional conditions and hydroclimate during the past 32 ka surface lacustrine sediments are characterized by low rb high sr low rb sr high caco 3 and high ca zr values in contrast to the chemical compositions of eolian loess high rb low sr high rb sr low caco 3 and low ca zr a direct comparison of soluble ca and sr in two short cores with instrumental water discharge data suggests that lacustrine precipitates in lake qinghai are dominated by authigenic aragonite formed under ca 2 limited water conditions and that the accumulation rate of aragonite dominantly depends on solute fluxes into the lake during the rainy seasons late may to september our high resolution down core records show that sediments during the last glacial 32 19 8 ka had high rb low sr low caco 3 and low ca zr indicating eolian dust loess accumulation in a desiccated basin under dry glacial conditions further supported by grain size and pollen results this type of sedimentation was maintained during the last deglacial 19 8 11 5 ka but interrupted by episodic lacustrine precipitates with high sr high caco 3 high ca zr and low rb at 11 5 ka sedimentary rb sr ca zr caco 3 and toc show dramatic and permanent changes implying an abrupt shift in the atmospheric circulation at the onset of the holocene in the lake qinghai region lacustrine precipitates have persisted throughout the holocene with a maximum during the early to mid holocene 10 5 8 0 ka since 8 0 ka the gradual and significant decreases in aragonite and sr accumulations in tandem with increasing dust deposit and more positive ostracod 18 o may be linked to a weakening of asian summer monsoons during the mid to late holocene overall our records appear to show a high sensitivity of sediment development and geochemistry in lake qinghai to the regional hydroclimate changes since the last glacial

late holocene climatic record from a glacial lake in ladakh range trans himalaya india a multi proxy study using mineral magnetism sediment texture total organic content palynofacies and diatoms was conducted in one of the highest proglacial lake situated at north pulu 5098 m a s

high resolution evidence from southern china of an early holocene optimum and a mid holocene dry event during the past 18 000 years abstract computer models suggest that the holocene optimum for east asian summer monsoon precipitation occurred at different times in different regions of china previous studies indicate that this time transgressive holocene optimum should have been experienced about 3000 yr ago in southern china in this study we describe a section which allows us to test this timing directly we have closely examined high resolution eutrophic peat mud sequences covering the past 18 000 cal yr at dahu jiangxi on the southern boundary of the mid subtropical zone in china late pleistocene successions in the dahu record indicate cooler and much wetter conditions relative to synchronous events in north central china our results indicate that the holocene optimum occurred between ca 10 000 and 6000 cal yr ago in southern china consistent with the global pattern conditions were relatively dry and cold from 6000 to 4000 cal yr ago our data also support the conclusion that the last deglaciation to early holocene in the south was much wetter resulting in the formation of dense broad leaved forests which could have acted to moderate land temperature 10 000 to 6000 cal yr ago yielding a stable early holocene climate after 6000 cal yr forest reduction led to unstable land temperatures and possibly to a northerly shift of the subtropical high pressure system whatever the mechanism these changes resulted in decreased precipitation between 6000 and 4000 cal yr b p in southern china

a holocene sedimentary record from bosten lake china abstract a 9 24 m long sediment record from the kaidu river delta margin of bosten lake northwestern china provides evidence for changes in water balance of the lake during the past 8600 calendar years quantitative and qualitative analyses of detrital components authigenic calcite toc and sr ca molar ratios as well as comparisons with selected ostracod assemblages show that lake level fluctuations at minimum 5 6 m display changes in effective moisture supply mainly driven by the west wind system distinct periods of negative water balances and thus dry conditions are dated to 8 5 8 1 7 3 7 1 around 6 0 at 5 4 5 0 4 6 4 3 3 9 3 6 3 4 3 2 2 6 2 5 1 9 1 1 0 5 0 3 and 0 18 0 05 cal ky bp and match the regional and global pattern of climate shifts during the holocene temporal shifts of moisture availability during mid holocene time were recognised as well and may be attributed to regionally different airflow conditions the last 150 years of rising lake levels are accompanied by strong eutrophication as a result of increased human impact

glacial lakes and geomorphological evolution of schirmacher oasis east antarctica during late quaternary large former glacial lakes and their sediments are described from the schirmacher oasis region of east antarctica the water bodies were present during the late quaternary 10 3 ka bp and have reduced in size by negative water balance this desiccation can possibly be attributed to the combined effect of recession of glaciers feeding them low melt water low precipitation and strong winds seven representative sections from five dry lake beds have been studied using loss on ignition loi and magnetic susceptibility ms the loi indicates a very low organic content while ms enables assumptions to be made about the reconstruction of changing detrital input detailed study of sediment profiles was used to reconstruct the evolution of the schirmacher oasis from 13 ka bp to the present these lacustrine sediments are a very important source of information on the quaternary geological history of the schirmacher oasis

geomorphological patterns in a linear dune field and ages of the linear dunes in the northern kumtagh desert northwest china the unique linear dunes in the northern kumtagh desert of northwest china have inspired enthusiastic debate among aeolian geomorphologists over their origins and classification their uniqueness lies not only in their morphology but also in their geomorphological patterns in this paper the geomorphological patterns and ages of the linear dunes in the northern kumtagh desert are analyzed using the pattern analysis method that was recently adopted by geomorphologists the analysis suggests that these linear dunes have developed since 13 ka bp during the late part of the most recent deglaciation stage when the region s dry climate was favorable for dune formation the differences in dune construction time within this region result from the complex factors that control their formation and spatial variations in the local environment but these factors were not strong enough to prevent us from estimating the dune age recorded by the geomorphological patterns with acceptable precision it is also suggested that the pattern analysis method can be used to estimate dune ages in the absence of more reliable dating methods

asynchronous evolution of the indian and east asian summer monsoon indicated by holocene moisture patterns in monsoonal central asia abstract the numerical meta analysis of 92 proxy records 72 sites of moisture and or temperature change confirms earlier findings that the dominant trends of climatic evolution in monsoonal central asia since the last glacial roughly parallel changes in northern hemisphere summer insolation i e the period following the last glacial maximum was characterized by dry and cold conditions until 15 cal kyr bp followed by a warm wet period coincident with the bolling allerod warm period and terminated by a cold dry reversal during the younger dryas period after an abrupt increase at the start of the holocene warm and wet conditions prevailed until ca 4 cal kyr bp when moisture levels and temperatures started to decrease ordination of moisture records reveals strong spatial heterogeneity in moisture evolution during the last 10 cal kyr the indian summer monsoon ism areas northern india tibetan plateau and southwest china exhibit maximum wet conditions during the early holocene while many records from the area of the east asian summer monsoon indicate relatively dry conditions especially in north central china where the maximum moisture levels occurred during the mid holocene we assign such phenomena to strengthened hadley circulation centered over the tibetan plateau during the early holocene which resulted in subsidence in the east asian monsoonal regions leading to relatively dry conditions our observations of the asynchronous nature of the two asian monsoon subsystems on millennial time scales have also been observed on annual time scales as well as implied through the spatial analysis of vertical air motion patterns after strong ascending airflows over the tibetan plateau area that were calculated from ncep ncar reanalysis data for the last 30 years analogous with the early holocene the enhancement of the ism in a future warming world will result in an increase in the asynchronous nature of the monsoon subsystems this trend is already observed in the meteorological data from the last 15 years

lake level variations of qinghai lake in northeastern qinghai tibetan plateau since 3 7 ka based on osl dating abstract qinghai lake is the largest internally drained lake in china and its unique location makes it sensitive to climate changes late glacial climate changes associated with variation in qinghai lake levels have been intensively investigated for the past 40 years with particular attention paid to lake level fluctuation histories between the last interglacial and the holocene however the details of lake level fluctuations during the holocene are still unclear using both optically stimulated luminescence osl dating of quartz for 22 samples and infra red stimulated luminescence irsl of feldspars only for sample hyw1 whose irsl age is 37 15 years a total of 23 samples are dated from paleoshoreline deposits fluvial sediments and aeolian sands a total of 13 sections near the modern lake shore with ages from 37 15 to 3710 350 years these ages are used to reconstruct the lake level fluctuation history spanning the last 3700 years the results indicate that 1 the youngest irsl age of 37 15 years is in agreement with the independent age of 39 29 years suggesting that luminescence dating is able to date decadal samples for sediments from the study area 2 the lake experienced several oscillations imposed on an overall regressive trend during the past 3700 years 3 the dated paleoshoreline deposits are generally related to warm and wet periods suggesting that those shoreline deposits formed during cold and dry periods if any may have been modified by later transgressions 4 lake level fluctuations during the period of 3700 240 years ago are generally consistent with the climate conditions identified in other proxies with the highest lake level occurring about 1770 years ago and 5 after 240 years ago the lake level dropped more rapidly which is inconsistent with the proxy records showing a warmer and wetter phase

rapid expansion of glacial lakes caused by climate and glacier retreat in the central himalayas glacial lake outburst floods are among the most serious natural hazards in the himalayas such floods are of high scientific and political importance because they exert trans boundary impacts on bordering countries the preparation of an updated inventory of glacial lakes and the analysis of their evolution are an important first step in assessment of hazards from glacial lake outbursts here we report the spatiotemporal developments of the glacial lakes in the poiqu river basin a trans boundary basin in the central himalayas from 1976 to 2010 based on multi temporal landsat images studied glacial lakes are classified as glacier fed lakes and non glacier fed lakes according to their hydrologic connection to glacial watersheds a total of 119 glacial lakes larger than 0 01km 2 with an overall surface area of 20 22km 2 10 8 were mapped in 2010 with glacier fed lakes being predominant in both number 69 58 0 and area 16 22km 2 80 2 we found that lakes connected to glacial watersheds glacier fed lakes significantly expanded 122 1 from 1976 to 2010 whereas lakes not connected to glacial watersheds non glacier fed lakes remained stable 2 8 during the same period this contrast can be attributed to the impact of glaciers retreating glaciers not only supply meltwater to lakes but also leave space for them to expand compared with other regions of the hindu kush himalayas hkh the lake area per glacier area in the poiqu river basin was the highest this observation might be attributed to the different climate regimes and glacier status along the hkh the results presented in this study confirm the significant role of glacier retreat on the evolution of glacial lakes copyright c 2014 john wiley sons ltd

palaeoenvironmental implications of evaporative gaylussite crystals from lonar lake central india we have undertaken petrographic mineralogical geochemical and isotopic investigations on carbonate minerals found within a 10 m long core from lonar lake central india with the aim of evaluating their potential as palaeoenvironmental proxies the core encompasses the entire holocene and is the first well dated high resolution record from central india while calcite and or aragonite were found throughout the core the mineral gaylussite was found only in two specific intervals 4630 3890 and 2040 560 cal a bp hydrochemical and isotope data from inflowing streams and lake waters indicate that evaporitic processes play a dominant role in the precipitation of carbonates within this lake isotopic d 18 o and d 13 c studies on the evaporative gaylussite crystals and residual bulk carbonates calcite from the long core show that evaporation is the major control on d 18 o enrichment in both the minerals however in case of d 13 c additional mechanisms for example methanogenesis gaylussite and phytoplankton productivity calcium carbonate play an additional important role in some intervals we also discuss the relevance of our investigation for palaeoclimate reconstruction and late holocene monsoon variability copyright 2013 john wiley sons ltd

a new approach to calculating holocene winter precipitation by combining glacier equilibrium line altitudes and pine tree limits a case stud from hardangerjokulen central southern norway at hardangerjokulen central southern norway detailed knowledge of the number age and magnitude of holocene glacier fluctuations is used to reconstruct variations in equilibrium line altitude ela for the last 10 000 years present and past elas are based on an accumulation area ratio aar of 0 7 and are adjusted for land uplift a synchronous relationship between advanced glacier positions and the highest pine tree limits pinus sylvestris l is demonstrated for the early to mid holocene in southern scandinavia which indicates that warm summers were compensated for by high winter precipitation based on pine tree limit fluctuations as a measure of mean ablation season temperature holocene variations in winter precipitation at hardangerjokulen have been calculated by substitution in the close exponential relationship between mean ablation season temperature and winter precipitation at the ela of norwegian glaciers setting the winter precipitation during the period ad 1961 1990 at 100 mean values

modern hydrology and late holocene history of lake karakul eastern pamirs tajikistan a reconnaissance study abstract lake karakul in the pamirs tajikistan is a deep brackish water lake in a closed basin at almost 4000 m above sea level water samples from the catchment area and lake karakul and a 104 cm sediment core from its shallow eastern sub basin were investigated and provide a first lake record from the region spanning the last 4200 cal yr bp multi proxy analyses revealed the following a relatively high meltwater inflow from glaciers snow fields and frozen ground in the catchment as a result of relatively warm conditions was reconstructed for the period between 4200 and 3500 cal yr bp the shift to colder climatic conditions around 3500 cal yr bp was probably abrupt total organic carbon values displayed the most dramatic drop for the entire core within less than 40 years in contrast the subsequent re establishment of warmer conditions occurred gradually over several centuries a higher meltwater supply to the lake and warmer conditions were recorded since ca 1900 cal yr bp with two slightly colder intervals between 1200 and 800 cal yr bp and between 400 and 100 cal yr bp the abrupt shift to significantly colder and drier conditions around 3500 cal yr bp in the eastern pamirs is seen also in records from the aral sea and the guliya ice core from the western tibetan plateau however more palaeoclimate studies in this highly continental part of central asia are needed to assess the spatial and temporal patterns of the holocene climate in the region

holocene variations in the asian monsoon inferred from the geochemistry of lake sediments in central tibet we present a record of monsoon variations for the early and middle holocene that is inferred from the geochemistry of sediment cores from ahung co a lake in central tibet the resolution of this record is better than 50 yr and the age model is derived from radiocarbon ages of terrestrial charcoal which eliminates errors associated with the lake hard water effect we made down core geochemical measurements of carbonate organic carbon c n and 13c of bulk organic matter 13c and 18o of carbonate and dolomite proxy calibration and modern water balance reconstruction show that these are proxies for lake depth and the amount of monsoon precipitation we find that lake level and monsoon precipitation have been decreasing at ahung co since the early holocene 7500 cal yr b p superimposed on this trend are rapid declines in monsoon rainfall at 7000 7500 and 4700 cal yr b p and seven century scale wet dry oscillations the cores do not contain sediment from the last 4000 yr surface sediments from the lake accumulated during the 20th century however from this we argue that lake levels have risen again recently following a late holocene dry period

tsunamis and submarine landslides in suruga bay central japan caused by nankai suruga trough megathrust earthquakes during the last 5000 years abstract magnitude 8 megathrust earthquakes that have generated large tsunamis with wave heights of 5 m in coastal areas of southwestern japan have occurred every 100 150 years along the nankai suruga trough which marks the convergent boundary between the eurasian and philippine sea plates using sedimentological geochemical and paleontological analyses as well as 14c dating we examined tsunami deposits in 12 sediment cores collected from the hamatome lowland yaizu plain shizuoka which faces the suruga trough four sandy tsunami deposits sands 1 4 are identified in sediments deposited during the last 5000 years sand 1 was deposited between 805 and 405 bc suggesting that only one tsunami left a sedimentological imprint in the hamatome lowland lagoon during the period of 4000 years between 3090 and 2913 bc and the ad 1096 eicho tokai earthquake this very low frequency of tsunami inundation may suggest that this tsunami was larger than those typically associated with megathrust earthquakes sands 2 4 are correlated with tsunamis associated with the eicho tokai ad 1361 shohei koan and ad 1498 meio tokai earthquakes respectively our data indicate that a sand spit which had previously protected the lagoon from oceanic waves was abruptly destroyed following the ad 1096 eicho tokai earthquake and did not re form at the same location this disappearance of the sand spit is inferred to have involved an earthquake induced submarine landslide the data presented in this paper together with information obtained from historical documents indicates that m8 megathrust earthquakes in ad 1096 and ad 1498 caused submarine landslides in the study area resulting in coastal subsidence and damage to coastal areas additional to that caused by the tsunamis

holocene glacier variations in central jotunheimen southern norway based on distal glaciolacustrine sediment cores abstract sediment cores from two glacier fed lakes are used to reconstruct a continuous record of glacier variations since about 10 000 cal bp in the smorstabbtinden massif of central jotunheimen southern norway particular attention is paid to the century to millennial scale pre little ice age glacial signal based on an estimated temporal resolution of 55 and 25 yr cm 1 for bovertunsvatnet and dalsvatnet respectively visible lithostratigraphic variations organic content loss on ignition calcium carbonate content magnetic susceptibility and grain size fractions especially the fine silt are used as proxy indicators of glacier presence and extent in the lake catchments following deglaciation the early holocene was characterized by generally small glaciers until a major advance the finse event peaking at approximately 8200 cal bp from 7900 to at least 5300 cal bp glaciers appear to have been absent from central jotunheimen there is evidence of glacier expansion between about 2400 and 1600 cal bp the bovertun i event and between about 1400 and 800 cal bp the bovertun ii event before reduced glacier extent during the mediaeval warm period finally the most extensive neoglacial maximum occurred during the little ice age after 500 cal bp in addition to providing a record of the broad pattern of climatically forced holocene glacier variations periodicities at 110 140 200 285 and about 500 yr have been identified uncertainties remain concerning the precise timing of events glacierization and deglacierization detection thresholds a possible mid to late holocene 5300 2500 cal bp neoglacial build up of small glaciers and shorter term decadal to century scale variations in glacier size for which more proximal sites are required

an upper pliocene lacustrine environmental record from south western australia preliminary results abstract a crater created by a supposed meteor impact and located about 30 5 s latitude in western australia contains a well preserved lake sequence of the upper pliocene age this paper reports on the palaeomagnetic record sediment patterns and selected chemical analyses and alludes to some of the preliminary results from pollen charcoal and diatom analyses the chemical analyses indicate that the lake varied in water depth and that salinity and diatom production were related to climate change rather than changes in major nutrients the palynological analysis for the upper 20 m of sediment shows a woodland and heath similar to today interspersed with some chenopod shrub land phases and minor elements include nothofagus araucaria and phyllocladus which are known from other tertiary records from southern western australia charcoal is abundant in the record indicating that fire was a major environmental feature long before aboriginal people inhabited the continent the palaeomagnetic record shows a good match with the gaussian chron and includes the kaena and mammoth subchrons and these were used as a basis for developing an age depth model for the sequence the sediment was subdivided into an upper unit of four lithozones and a lower unit the upper unit that dates from ca 2 5 to 3 51 ma was interpreted to have formed under a generally wetter climate than today and with some relatively short intervals of semi arid climate identified around 2 56 and 2 59 ma they were interpreted from episodes of chenopod shrub land that were associated with assemblages of saline habitat diatoms and carbonate and gypsum in the sediments the sediment profile also included sections of laminated sediments which indicate that around 2 82 2 86 and 2 96 ma the climate was more variable and possibly seasonal compared to the rest of the record these data indicate that the last million years of the pliocene for south western australia endured several episodes of climate variability thus lending support to the idea that the pliocene was not a period of a uniform cooling trend gradually leading into the quaternary glacial episodes

vegetation response to holocene climate change in east asian monsoon margin region abstract fossil pollen records from 20 sites with reliable chronologies and high resolution data in the east asian monsoon margin region were synthesized to document holocene vegetation and climate change and to understand the large scale controls the vegetation experienced different changes over the holocene in various sub regions 1 near the boundary between modern forest and temperate steppe in northeast china forest showed clear expansion in the middle holocene 2 in central china near the boundary between steppe forest and desert vegetation showed various patterns at different sites 3 further west on the tibetan plateau near the boundary between highland meadow steppe and semi desert desert forest expanded at most sites during the early and middle holocene our synthesis indicates that climate in the margin region was slightly moist in the early holocene wettest in the middle holocene and dry in the late holocene though there are regional differences as reflected by vegetation change this general pattern is very different from either monsoon or westerly dominated regions the maximum moisture occurred during the early holocene in the monsoon region while the arid central asia dominated by the westerlies was driest in the early holocene and wettest in the mid holocene the interplay of the asian summer monsoon westerlies topography and regional vegetation factors might have contributed to this spatial complexity