holocene sea level change and the emergence of neolithic seafaring in the fuzhou basin fujian china abstract neolithic seafaring across the taiwan strait began approximately 5000 years ago and involved open sea voyages over distances of at least 130 km rapid sea level rise preceded the emergence of open sea voyaging but the possible role of environmental change as a stimulus for the development of seafaring is poorly understood we investigate this problem by presenting a record of holocene sea level change and coastal transformation based on sediment cores obtained from the fuzhou basin on the coast of fujian china the cores are located in direct proximity to archaeological sites of the tanshishan neolithic culture 5000 4300 cal bp which is significant for its similarity to the earliest neolithic cultures of taiwan multiple lines of evidence record the early holocene inundation of the fuzhou basin around 9000 cal bp the mid holocene sea level highstand and the final holocene marine transgression this final transition is precisely documented with ams dates showing the change occurred close to 1900 cal bp our paleogeographic reconstruction shows that a large estuary filled the fuzhou basin during the mid holocene tanshishan and zhuangbianshan two of the major fuzhou basin neolithic sites are located today on hills nearly 80 km from the modern coastline however when the sites were settled around 5500 5000 cal bp the marine transgression had transformed these hills into islands in the upper estuary we suggest that the neolithic era estuary setting together with the lack of land suitable for rice paddy agriculture inhibited intensive food production but favored a maritime orientation and the development of seafaring

late quaternary environmental changes in the pearl river mouth region china abstract this study presents findings concerning late quaternary environmental changes in the pearl river mouth region china based on the study of over 300 boreholes out of these 35 boreholes are selected for the reconstruction of transects across the deltaic plain and estuary 39 radiocarbon dates obtained from these boreholes are used to help define the chronology of stratigraphic units present including two terrestrial units t1 and t2 and two marine units m1 and m2 diatom assemblages are studied in 6 boreholes revealing similarities and differences between the two marine units before the area was inundated by the last interglacial sea mis 5 an older terrestrial unit of sand and gravel t2 was laid down in a number of palaeo valleys during the last interglacial period an older marine unit of silt and clay m2 was laid down which was subsequently subaerially exposed when sea level regressed during the last glacial period mis 4 2 causing the uppermost section to be weathered during the same period a younger terrestrial unit of sand and gravel t1 was deposited along palaeo river channels around the early holocene before 8 2 cal ka bp the postglacial rise in sea level initiated a new phase of sedimentation in the outer part of the estuary characterised by the high percentages of marine diatoms in the sediments in the early holocene strong monsoon freshwater discharge resulted in sedimentation of a fine sand layer in the inner part of the estuary after 8 2 cal ka bp rapid rises in sea level caused widespread marine inundation and sedimentation the diatom data suggest that the relative sea level associated with the m2 and m1 units were both at similar levels because the m2 unit is typically recorded at altitudes of 15 m and 20 m below the present sea level this is likely to be a result of long term subsidence although numerical dating of the pre m1 units has not been made in the present study the chronology of these units can be inferred from uranium series ages and optically stimulated luminescence dating obtained from the adjacent coastal waters of hong kong the t1 unit has yielded ages of about 30 0 cal ka bp while the m2 unit has yielded ages about 130 0 cal ka bp confirming their mis 4 2 and mis 5 ages respectively

pollen record of the past 60 ka bp in the middle okinawa trough terrestrial provenance and reconstruction of the paleoenvironment abstract core dgks9602 931 cm in length was retrieved from the middle okinawa trough the age model was correlated with the adjacent core dgks9603 li et al 2001 for the upper part and to the standard specmap chronology down to 60 ka bp using marine oxygen isotope control points pollen analysis was carried out and seven pollen zones were identified the results showed that the pollen spectra in mis 3 were very different to mis 2 but comparable with the holocene the saccate pollen principally pinus predominated in most parts of the core except for the interval of the last glacial maximum lgm and the late mis 3 when artemisia and other herbs increased prominently the ratios of p a pinus artemisia and of pb nap pollen with bladders versus non arboreal pollen were used as a proxy for sea level change and for estimating distances from the coastline to the study site the provenance study using a modern analog technique based on the east asian modern pollen database and fossil pollen assemblages revealed that the pollen were derived from diverse source areas during different stages since 60 ka bp the pollen zones equivalent to mis 1 and 3 were characterized by uncertain and disparate areas of provenance and the surrounding continents including eastern mainland china korea and southern japan possibly made equivalent contributions which may be the result of enhanced pollen transport by the northwesterly wind however the lgm represented in core dgks9602 was distinguished by restricted sources from the exposed east china shelf where the vegetation was quite similar with the herb coverage in the present day north china plain the pollen assemblages sensitively reflected the coastline changes marked by transport patterns between fluvial runoff and northwesterly winds plus ocean currents some pollen changes and limits of pollen zones coincided with the timing of heinrich events implying that the rapid climate fluctuations during mis 3 and mis 2 may have partially resulted in the forest changes in eastern asia the pattern of relative abundance of subtropical and total arboreal taxa is consistent with that of 18 o from hulu cave implying monsoonal climatic control over vegetation change the estimated temperature mat by the means of pollen ratios for the lgm was 5 8 c lower than that in the changjiang river mouth today

elevation changes and the great 1960 chilean earthquake support for aseismic slip we reanalyse the near field vertical displacement data for the great chilean earthquake of 1960 to provide constraints on the down dip slip distribution a recent study of free oscillation data confirms earlier proposals of a slow precursor comparable in size to the main shock we seek evidence for this event in the displacement data spatial coverage of the data is inadequate to allow determination of a unique fault model but inversions show that thrust slip must extend over a width of about 300 km and to a depth between 60 km and 85 km well below the seismogenic zone for interplate events we propose that this deeper slip is the source of the slow event our preferred class of solutions has moments ranging from 1 6 1023 n m to 2 5 1023 n m only 30 to 45 of the free oscillation value underestimation of the near trench displacements by 50 together with a seismic overestimation of moment by 30 due to tradeoff with rise time would result in satisfactory agreement

pollen quantitative distribution in marine and fluvial surface sediments from the northern south china sea new insights into pollen transportation and deposition mechanisms in order to improve the understanding of pollen transportation and deposition mechanisms in northern south china sea scs 45 seafloor surface sediment samples from the scs and nine surface sediment samples from the pearl river mouth were analyzed palynologically the spatial distributions of pollen and spore taxa suggest that various transport mechanisms and the production at the source the dominant pollen pinus poaceae cyperaceae and fern spores are most abundant in the river mouth and decrease with increasing distance from the land suggesting they are mainly derived from the pearl river drainage basin and strongly dispersed by river plume and ocean currents which reflects a dominant pollen transportation pattern in the northern scs podoconpus and temperate broad leaved components pollen such as evergreen quercus and castanopsis pollen is common in marine samples and is scattered in the pearl river samples reflecting their extensive source areas and dispersal in more than one route however some pollen types of conifers are mostly deposited close to the shore such as dacrydium picea and abies which are restricted near hainan island and taiwan island excluding evergreen quercus and castanopsis pollen the total tropical and subtropical components poorly reflect their parent plants and fewer such pollen are transported over long distances however the source areas of some other pollen taxa e g phyllociadus artemisia and chenopodiaceae are unclear spatially varying ratios of spores to pollen indicate that spores are relatively easily transported by water over longer distances than are pollen grains this study provides a sound basis for interpreting quaternary pollen deposits from the northern scs and for further evaluation of pollen dispersal and deposition in marine and fluvial deposits c 2013 elsevier ltd and inqua all rights reserved

patterns of vegetation and climate change in the northern south china sea during the last glaciation inferred from marine palynological records abstract high resolution marine palynological records from the northern south china sea scs provide new information concerning the regional history of vegetation and climate conditions during the last glaciation 70 19 cal ka bp the preservation of rich pollen from tropical and subtropical broadleaf trees largely composed of evergreen quercus castanopsis and euphorbiaceae suggests that a southern subtropical climate prevailed during the last glaciation including the period of the last glacial maximum relatively higher percentages of such pollen taxa occurred during marine isotope stage mis 3 when phyllocladus pollen from the south also increased indicating a warmer terrestrial climate and a strengthened east asian summer monsoon comparing to mis 4 and 2 moreover the maximum percentages of such pollen occurred during the early mis 3 implying that an optimal climate prevailed in this period the reconstructed terrestrial climate corresponds well to marine evidence such as 18o values from planktonic foraminifer shell and records of sea surface temperature this study confirmed that the regional terrestrial climate could be linked closely to changes in both global ice volume and the east asian monsoon attributable to variations of the earth s orbital parameters modern palynological investigations and statistical analyses of the pollen percentages in the profiles indicate that pinus pollen and spores are easily transported by water flow in the northern scs therefore their relative abundance peaks suggest that several wet intervals occurred during the last glaciation

pollen distribution in marine surface sediments from chilean patagonia abstract southern south america is the only mid to high latitude continental landmass in the southern hemisphere and therefore represents one of the key areas to recover terrestrial records for the study of past and future climate variability at these latitudes during cruise md 159 of r v marion dufresne cores were taken off the chilean coast from 40 to 55 s in the open ocean and the fjords pollen spectra of 32 core top samples illustrate the relationships between pollen distribution in the sampled marine sediments and their transport from the vegetation onshore pollen concentrations show two distinct gradients 1 a north to south gradient controlled by latitudinal vegetation changes and by westerly winds and 2 from the fjords to the open ocean a gradient clearly controlled by wind fluvial inputs and pollen diagenesis linked to the distance from the coast and water depth the distribution of pollen percentages in these marine surface sediment samples reflects the local vegetation from the nearby continental area consequently pollen analyses from older sediments in these marine cores will be reliable tools to reconstruct past vegetational changes

the huguang maar lake a high resolution record of palaeoenvironmental and palaeoclimatic changes over the last 78 000 years from south china abstract a series of seven piston cores from the huguang maar lake situated near the south china sea coastline provides insight into regional palaeoenvironmental and palaeoclimatic changes in southern china over the last 78 000 years the data set comprises a high resolution record of magnetic susceptibility dry density and water content total organic carbon and inorganic carbon total nitrogen biogenic silica bsio2 and palynological results the time scale was developed by ams 14c dating of 17 terrestrial plant macro fossils during the last glacial the huguang record is characterised by an alternation of more temperate and humid periods from 78 to 58 and 48 to 40 5 ka bp and periods with predominance of grassland vegetation and possibly lowered lake level from 58 to 48 and ca 40 5 to 15 ka bp the huguang data have been compared to regional marine and terrestrial records in order to discuss variability of the south east asian monsoon system for most of the last glacial period the huguang proxies do not exhibit marked millennial scale variability as known from some long se asian and many north atlantic records this picture changes at about 15 cal ka bp when the huguang and greenland records appear to correlate well a short climatic reversal which is assumed to reflect a younger dryas type event is well recorded in the huguang record during the holocene the huguang multi proxy data show a much higher variability than during the last glacial stage probably reflecting at least for the early mid holocene fluctuations in monsoon activity however the last 4000 years of the sediment record are clearly influenced by enhanced human activity and thus difficult to interpret in terms of palaeoclimate change

the sedimentary and tectonic evolution of the yinggehai song hong basin and the southern hainan margin south china sea implications for tibetan uplift and monsoon intensification 1 the yinggehai song hong basin is one of the world s largest pull apart basins lying along the trace of the red river fault zone in the south china sea south of hainan island this basin crosscuts the rifted margin of the northern south china sea in this paper we present for the first time a regional compilation of multichannel seismic reflection data from both the strike slip and rifted margins the basins started to open after similar to 45 ma especially after similar to 34 ma the yinggehai basin was folded and inverted in the middle miocene after 21 ma in the north and 14 ma in the south before rapidly subsiding again after similar to 5 ma because of continued tectonism this subsidence has caused shale diapirism especially driven by associated sedimentation in the late pliocene 2 6 2 0 ma extension along the adjacent south hainan margin shows preferential lower crustal extension suggestive of lower crustal flow increasing toward the continent ocean transition during breakup sediment supply is reconstructed to peak in the middle miocene then falls between 14 and 10 3 ma to reach a low in the late miocene however rates rose again in the pliocene pleistocene the red river sediment budget is incompatible with climate models that propose stronger monsoon rains starting at 8 ma or with large scale river capture away from the red river after similar to 10 ma both lines of evidence point to major uplift in the red river drainage being middle miocene or older the recent preindustrial red river carried much more sediment than the average pleistocene accumulation rate indicating modest sediment buffering onshore at least in recent geologic time

rotation narrowing and preferential reactivation of brittle structures during oblique rifting abstract occurrence of multiple faults populations with contrasting orientations in oblique continental rifts and passive margins has long sparked debate about relative timing of deformation events and tectonic interpretations here we use high resolution three dimensional thermo mechanical numerical modeling to characterize the evolution of the structural style associated with varying geometries of oblique rifting in a layered continental lithosphere automatic analysis of the distribution of active extensional shear zones at the surface of the model demonstrates a characteristic sequence of deformation phase 1 with initial localization of deformation and development of wide moderately oblique en echelon grabens limited by extensional shear zones oriented close to orthogonal to 3 trend subsequent widening of the grabens is accompanied by progressive rotation of the phase 1 extensional shear zones to an orientation sub orthogonal to the plate motion direction phase 2 is characterized by narrowing of active deformation resulting from thinning of the continental mantle lithosphere and development of a second generation of extensional shear zones during phase 2 deformation localizes both on plate motion direction orthogonal structures that reactivate rotated phase 1 shear zones and on new moderately oblique structures parallel to 2 finally phase 3 consists in the oblique rupture of the continental lithosphere and produces an oceanic domain where oblique ridge segments are linked with highly oblique accommodation zones we conclude that while new structures form and trend parallel to 2 in an oblique rift progressive rotation and long term slip along phase 1 structures promotes orthorhombic fault systems which accommodate upper crustal extension and control oblique passive margin architecture the distribution orientation and evolution of frictional plastic structures observed in our models consistent with documented fault populations in the main ethiopian rift and the gulf of aden conjugate passive margins both of which developed in moderately oblique extensional settings

reconstructing pathways of aeolian pollen transport to the marine sediments along the coastline of sw africa the distribution of pollen in marine sediments is used to reconstruct pathways of terrigenous input to the oceans and provides a record of vegetation change on adjacent continents the wind transport routes of aeolian pollen is comprehensively illustrated by clusters of trajectories isobaric 4 day backward trajectories are calculated using the modelled wind field of echam3 and are clustered on a seasonal basis to estimate the main pathways of aeolian particles to sites of marine cores in the south eastern atlantic trajectories and clusters based on the modelled wind field of the last glacial maximum hardly differ from those of the present day trajectory clusters show three regional and two seasonal patterns determining the pathways of aeolian pollen transport into the south eastern atlantic ocean mainly transport out of the continent occurs during austral fall and winter when easterly and south easterly winds prevail south of 25 s winds blow mostly from the west and southwest and aeolian terrestrial input is very low generally a good latitudinal correspondence exists between the distribution patterns of pollen in marine surface sediments and the occurrence of the source plants on the adjacent continent the northern angola basin receives pollen and spores from the congolian and zambezian forests mainly through river discharge the zambezian vegetation zone is the main source area for wind blown pollen in sediments of the angola basin while the semi desert and desert areas are the main sources for pollen in sediments of the walvis basin and on the walvis ridge a transect of six marine pollen records along the south western african coast indicates considerable changes in the vegetation of southern africa between glacial and interglacial periods important changes in the vegetation are the decline of forests in equatorial africa and the north of southern africa and a northward shift of winter rain vegetation along the western escarpment

source to sink transport processes of fluvial sediments in the south china sea the south china sea offers an excellent case for studying source to sink transport processes of fluvial sediments among the global marginal seas this study synthesizes existing clay mineralogical and geochemical data from similar to 1500 samples from the seafloor and surrounding rivers deepwater mooring observation results and high resolution glacial cyclic clay mineralogy records from six high quality sediment cores source to sink sediment transport from the river mouth to the continental shelf and then to the abyssal basin is investigated at two time scales modern process and late quaternary glacial cycles the results firstly show the high diversity of clay mineralogical and geochemical compositions in riverbed surface sediments surrounding the south china sea e g dominant illite and chlorite in taiwan overwhelming majority of smectite in luzon dominant kaolinite in south china and similar amounts of the four clay mineral species in red and mekong river systems the formation of these fluvial sediments through chemical weathering in surrounding drainage systems is controlled principally by the east asian monsoon climate with warm temperature and high precipitation and subordinately by tectonic activity and specific lithological character the basin wide distribution of clay mineral assemblages combined with neodymium and strontium isotopic compositions reflects strong provenance control and differential settling effects the differential settling of kaolinite in slightly saline and proximal regions relative to smectite in more saline and distal regions is well demonstrated in the south china sea through combining clay mineralogical distributions on the seafloor with observed oceanic current systems the modern transport pathways can be well established e g in the northern south china sea illite and chlorite from taiwan are mainly carried by contour currents with the strong influence of mesoscale eddies high resolution sediment dynamic analysis for the late quaternary reveals different sediment transport patterns in the northern western and southern south china sea when the land sea configuration dramatically changed during glacial conditions in the north the terrigenous dispersal is mainly controlled by provenance supply and oceanic current transport in the west the clay mineral assemblage reflects variations of the prevailing surface current influenced by monsoon winds in the south the clay mineral input indicates intensive chemical weathering during interglacial periods and strengthened physical erosion during glacial periods the transport of terrigenous sediments since the last glaciation is quantitatively reconstructed through studying two deepwater sediment cores located in the northern south china sea the relative contributions from three provenances south china luzon and taiwan highlight their distinct variability over the last 28 ka implying that the southward shift of the inter tropical convergence zone itcz at 16 ka bp caused an increased sediment contribution from south china the intensified influence of the kuroshio current intrusion controls more efficient westward transport of luzon sediments and the stronger deepwater current transports taiwan sourced sediments further westward from the last glaciation to the holocene c 2015 elsevier b v all rights reserved

pollen stratigraphy vegetation and environment of the last glacial and holocene a record from toushe basin central taiwan abstract the pollen record from the toushe basin 23 49 n 120 53 e 650 m above sea level a peat bog of central taiwan displays a continuous vegetation history of the past 96 000 yr bp of monsoon asia instead of today s closed subtropical evergreen broadleaved forest dominated by machilus castanopsis surrounding the basin temperate deciduous forest predominated during most of the last glacial in early mis 4 alnus reaches the highest value of the whole sequence 60 70 representing temperate deciduous forest and relatively cold and arid conditions following this stadial alnus and herbs mainly cyperaceae dominated alternately with a minor increase of castanopsis peaks of monolete spores between cal 42 2 and 37 0 kyr bp kyr bp represent calibrated years indicate episodic wet conditions the later glacial especially between 23 2 and 18 7 kyr bp shows a high percentage of gramineae indicating dry and possibly sometimes cold conditions the late glacial shows a remarkable increase of warm temperate to temperate forest elements such as ilex cyclobalanopsis and symplocos at about 15 1 kyr bp a peak of monolete spores indicates wet warm conditions a subsequent sharp increase of salix and then gramineae between 13 0 and 11 6 kyr bp corresponds to the younger dryas a warming event at 11 5 kyr bp is also evident the holocene is characterized by warm wet conditions of the overwhelmingly abundant monolete spores since 10 7 kyr bp and the prominent increase of castanopsis

chilean and southeast pacific paleoclimate variations during the last glacial cycle directly correlated pollen and δ18o records from odp site 1234 abstract joint pollen and oxygen isotope data from ocean drilling program site 1234 in the southeast pacific provide the first continuous record of temperate south american vegetation and climate from the last 140 ka located at 36 s 65 km offshore of concepcion chile site 1234 monitors the climatic transition zone between northern semi arid summer dry winter wet climate and southern year round rainy cool temperate climate dominance of onshore winds suggests that pollen preserved here reflects transport to the ocean via rivers that drain the region and integrate conditions from the coastal mountains to the andean foothills down hole changes in diagnostic pollen assemblages from xeric lowland deciduous forest characterized by grasses herbs ferns and trees such as deciduous beech nothofagus obliqua mesic valdivian evergreen forest including conifers such as the endangered prumnopitys andina and subantarctic evergreen rainforest comprised primarily of southern beech n dombeyi reveal large rapid shifts that likely reflect latitudinal movements in atmospheric circulation and storm tracks associated with the southern westerly winds during glacial intervals mis 2 4 and 6 rainforests and parkland dominated by nothofagus moved northward into the region at the mis 6 5e transition coeval with the rapid shift to lower isotopic values rainforest vegetation was rapidly replaced by xeric plant communities associated with mediterranean type climate an increased prominence of halophytic vegetation suggests that mis 5e was more arid and possibly warmer than mis 1 although rainforest pollen rises again at the end of mis 5e lowland deciduous forest pollen persists through mis 5d and 5c into mis 5b substantial millennial scale variations occur in both interglacial and glacial regimes attesting to the sensitivity of the southern westerly belt to climate change comparison of the cool mesic n dombeyi rainforest assemblage from site 1234 with 18 o in the byrd ice core shows that on time scales longer than 10 ka cool moist conditions in central chile were coherent with and occurred in phase with antarctic cooling this is also likely at millennial scales although rainforest pollen lags antarctic cooling with exponential response times of about 1000 years which plausibly reflects the ecological response time to regional climate change

pollen record in the northwestern continental shelf of the south china sea in the past 82 ka paleoenvironmental changes in the last glacial period abstract the northwestern continental shelf of the south china sea scs is in a geographic location that was sensitive to the global paleoenvironmental change during the last glacial period here we present a high resolution palynological record of core zbw 100 65 m in length from the continental shelf of the scs in the past 82 ka in contrast to results for the northern scs the core s pollen assemblage was dominated by arboreal trees between mis5a and mis1 even during the glacial period pollen provenance analyses indicated it was mainly from the drainage basin of the red river the yungui plateau and tibetan plateau between 66 and 64 ka the contribution of pinus fell while that of cyclobalanopsis and trilete spores increased indicating a drier and cooler climate conversely during mis3 the contributions of pinus and lowland trees were high indicating a warm and wet climate the sedimentary environment in core zbw alternated between coastal marine and river alluvial or shore facies a sedimentary hiatus between 42 and 13 ka coincided with a significant fall in sea levels seismic data indicate that the hainan paleo river delta hprd process occurred at the core site between 65 and 56 ka with extremely high rates of sediment deposition pollen data indicate the hprd process was coincided with a transition period from cooler and drier climate to warmer and wetter climate and lower sea levels to higher sea levels

a 400 000 year record of vegetational and climatic changes from a volcanic basin leizhou peninsula southern china abstract the tianyang lake in leizhou peninsula is an enclosed crater formed during the early to middle pleistocene over 200 m of diatomaceous mud and clay were deposited in the last 400 000 years providing a continuous middle and late quaternary lacustrine sequence for paleoenvironmental studies the pollen record spans the last four glacial interglacial cycles equivalent to oxygen isotope stages ois 10 to 1 during most of the glacial phases fagaceous monsoon forest was replaced by altitudinal vegetation indicating a regional landscape transformation on the peninsula the montane forest reached down to the lowland by at least 600 m during the ois 6 and 8 in a cool and relatively wet condition with temperature estimated to be more than 4 c lower than present a further lowering of the montane forest belts by about 800 1000 m occurred in the ois 4 2 as implied by the appearance of many temperate elements during the last glacial maximum this mixed forest subsequently gave way to the poaceae grassland a savanna vegetation type favored by drier and cooler climatic conditions this drastic change implies a more significant drop in temperature and precipitation than the previous three glacial periods ois 10 8 and 6 it is thus inferred that the weakening of summer monsoon was more significant towards the end of the late pleistocene particularly during the last glacial maximum lgm

last glacial pollen record from lanzhou northwestern china and possible forcing mechanisms for the mis 3 climate change in middle to east asia abstract the vegetation on the northeastern margin of the tibetan plateau is highly sensitive to climatic changes and thus represents a potentially interesting environmental archive pollen samples from the fanjiaping loess section in lanzhou on the western chinese loess plateau clp were analyzed in conjunction with osl dating the results indicate that pollen zone b 60 6 46 0 ka correlative to the early mis 3 had the greatest abundances of cupressaceae tsuga gramineae and cyperaceae of the entire section suggesting a warm phase during the last glacial period these pollen taxa decreased significantly in abundance in the zones c 46 0 39 0 ka and d 39 0 27 0 ka reflecting a substantial climate cooling from the middle mis 3 to mis 2 these results correlate with climate records from the south china sea the clp baikal lake north america north atlantic ocean and other regions and probably correspond with the decline of northern high latitude insolation and the increase of global ice volume from 50 to 20 ka in particular arboreal pollen fern spore and algae abundances declined sharply since 40 ka while shrub and herb pollen reached the highest abundances conifer pollen picea and abies abundance also rose markedly and increased up the section this implies significant climate deterioration and likely corresponded with substantial growth of the polar ice sheets since 40 ka the decreasing temperature caused by an insolation decline during the last glacial period probably reinforced the cooling effect in a snow ice albedo feedback which would result in less climate sensitivity to radiative forcing meanwhile vegetation decline in the northern hemisphere during the last glacial period and tundra development at high latitudes possibly caused additional cooling enhancing the growth of polar ice sheets since 40 ka the development of polar ice sheets increased the polar to equator temperature and pressure gradients strengthening the westerlies and supplying plenty of moisture to northwest china during 40 30 ka lake sediments developed widely on the tibetan plateau during 40 30 ka probably related to an increase in the seasonality of middle to low latitude insolation which caused an enhancement of glacier melting on the plateau

deep sea pollen from the south china sea pleistocene indicators of east asian monsoon abstract a high resolution pollen record sampling interval averages 820 years has been obtained from odp site 1144 water depth 2037 m northern south china sea the 504 m sequence in composition length covers the last 1 03 million years according to micropaleontological and isotopic stratigraphy the pollen assemblages are characterized by high proportions of pinus and herb pollen and by their frequent alternations based on these alternations 29 pollen zones have been recognized that are closely correlated to the marine oxygen isotope stages mis 1 29 pinus dominant pollen zones correspond to interglacial periods with lighter 18o values while herb marked ones relate to the heavier 18o stages assigned to glacials judging from the pollen data the exposed northern continental shelf of the south china sea during the glacials was covered by grassland and the extensive northern shelf has formed only since mis 6 ca 150 ka probably as a result of tectonic subsidence tree pollen influx values are indicative of winter monsoon which began to intensify 600 ka ago the summer monsoon variations can be approximated by the fern percentage within the total pollen and spore abundance and the result shows high values in general occurring at interglacials with the maxima at mis 15 5e and 1 the relatively high fern percentage with smaller amplitude in variations before 600 ka might suggest more stable humid conditions before the intensification of winter monsoon

high resolution sea surface temperature records derived from foraminiferal mg ca ratios during the last 260 ka in the northern south china sea abstract high resolution sea surface temperatures sst derived from mg ca ratios of globeriginoides sacculifer at odp site 1144 were reported to reveal the sst changes during the last 260 ka in the northern south china sea scs the results indicate an average holocene sst of about 26 7 c about 3 6 c increase from lgm to the holocene and higher temperature during mis 5 5 than the holocene these agree well with other foraminifer mg ca and uk37 sst records in this region the mg ca records suggest warmer ssts during mis 3 in the northern scs compared with those in the eastern pacific strong east asian summer monsoon during mis 3 indicated by paleoclimate records from nearby continents may account for it step wise increases during terminations are shown in our sst record and the beginning of deglacial warming occurs at about 19 ka which precedes the change of oxygen isotopes suggesting a tropical driven forcing for the sst change in the northern scs this is further supported by a robust semi precessional cycle centering at 9 1 ka in the spectra of the sst record which is absent in that of the oxygen isotopes however tropical driven forcing seems not to be indicated in another mg ca sst record in the northern scs oppo d w and sun y b 2005 amplitude and timing of sea surface temperature change in the northern south china sea dynamic link to the east asian monsoon geology 33 10 785 788 the discrepancy may be caused by different post deposition dissolutions of foraminifer tests at these two sites details about the modification of foraminifer mg ca ratios after burial however are not well known in this region and further studies are needed

modern pollen distribution in marine sediments from the northern part of the south china sea we analyzed the pollen and spore distributions in sediments from the northern south china sea to support reconstruction of the region s paleoenvironment 1 based on pca analysis in the two areas with water depths of 200 m pollen and spores found at water depths of 200 m wind transport is dominant 2 tree pollen was abundant on the continental shelves near guangdong and southeastern hainan island the center of the study area and deep basins in the south pinus pollen was abundant with the highest levels on the continental shelf near guangdong and in the marine area south of 15 degrees n pollen from tropical and subtropical broad leaved trees e g castanopsis quercus had low abundances castanopsis pollen appeared to originate near hainan island guangdong and the indochina peninsula herbaceous pollen was less abundant with pollen from the poaceae and artemisia scattered among the northern and southern regions with the highest levels near guangdong and a distribution that followed the rivers or sea surface circulation poaceae pollen was most abundant along the guangdong and vietnam coasts due to their proximity to tropical and subtropical grasslands and crops monolete spores and cyperaceae pollen were most abundant near the pearl river estuary southern hainan island and southwestern taiwan probably originating from fluvial river discharge trilete spores mostly dicranopteris were most abundant on the continental shelf of southeastern hainan island and the continental slope far from guangdong 3 pollen and spore assemblages from airborne sea surface water and sediment samples were compared from august to september airborne pollen and spores mainly belong to trees ulmaceae pinus and herbaceous pollen and have seasonal characteristics ocean surface waters in august september mainly contain d dichotoma rhizoma polypodiodis nipponicae and other trilete spores but no pinus pollen with clear seasonality characteristic pollen and spore assemblages in surface sediments are dominated by trilete spores pinus and herbaceous pollen and appear to integrate the pollen characteristics of the four seasons c 2014 elsevier b v all rights reserved

changes in monsoon and ocean circulation and the vegetation cover of southwest sumatra through the last 83 000 years the record from marine core bar94 42 abstract we present the palynological record from deep sea core bar94 42 taken offshore of southwest sumatra in the indian ocean refinement of a previous age model for the core has been made using 7 additional radiocarbon ages and 29 additional oxygen isotope measurements these analyses have substantially improved the previously published chronology which has enabled revision of the results of sedimentological studies of the core the pollen and re interpreted biogenic and terrigeneous data were used to reconstruct monsoon circulation and vegetation of southwest sumatra over the last 83 000 years 83 kyr during marine isotope stage mis 5a southwest sumatra was covered by rainforest with open herbaceous swamps lining river courses and surrounding lakes the se component of the monsoon was stronger than the nw component resulting in a humid climate with a short dry season during mis 4 conditions were drier fire activity increased and the monsoon was generally weaker this latter pattern persisted until mis1 the vegetation was most open during mis 3 between 52 and 43 kyr identifying this phase as the driest of the last glacial an increase in montane trees from 52 kyr indicates the onset of cooler conditions which lasted until the transition to mis 1 at about 11 9 kyr after 43 kyr an everwet climate gradually developed as monsoonal circulation intensified and the se monsoon component became stronger during this time closed canopy rainforest became dominant regionally over southwest sumatra increased monsoonal activity during the early holocene resulted in increased precipitation river runoff sediment discharge and offshore sediment transport from the continental shelf

evidence for general instability of past climate from a 250 kyr ice core record recent results1 2 from two ice cores drilled in central greenland have revealed large abrupt climate changes of at least regional extent during the late stages of the last glaciation suggesting that climate in the north atlantic region is able to reorganize itself rapidly perhaps even within a few decades here we present a detailed stable isotope record for the full length of the greenland ice core project summit ice core extending over the past 250 kyr according to a calculated timescale we find that climate instability was not confined to the last glaciation but appears also to have been marked during the last interglacial as explored more fully in a companion paper3 and during the previous saale holstein glacial cycle this is in contrast with the extreme stability of the holocene suggesting that recent climate stability may be the exception rather than the rule the last interglacial seems to have lasted longer than is implied by the deep sea specmap record4 in agreement with other land based observations5 6 we suggest that climate instability in the early part of the last interglacial may have delayed the melting of the saalean ice sheets in america and eurasia perhaps accounting for this discrepancy

a continuous record of vegetation and climate change over the past 50 000years in the fujian province of eastern subtropical china abstract a 425 cm core has been collected from the gantang subalpine peat bog in pingnan county fujian province of southern china high resolution pollen analysis of the core has allowed for the reconstruction of past vegetation and climate changes over the last 50 000 years today fujian province is located in the eastern part of middle subtropical zone where the dominant vegetation is evergreen broadleaved forest that receives its precipitation from the east asian monsoon the pollen record testifies that the vegetation in fujian varied between subtropical evergreen and warm temperate deciduous forests during the last glacial interglacial cycle it appears that during marine oxygen isotope stage 3 this area was covered with broadleaved forest suggesting warm and wet subtropical condition whereas the flora was quite different with many ancient elements the last glacial maximum is distinguished by an increase in warm temperate deciduous taxa particularly fagus and alnus accompanied by abundant ericaceae implying a spatial shift of zonal vegetation during this coldest episode in the world local swamp developed soon after the younger dryas event coinciding with the formation of peatlands in the northern hemisphere possibly linked with atmospheric carbon accumulation a rapid increase in evergreen broadleaved taxa that dominated the local forest occurred at ca 8 2 cal ka bp indicating the inception of the regional thermal maximum during the holocene which was generally characterised by more humid conditions the middle to late holocene sees a progressive decline in arboreal elements and an increase in grasses and ericaceae these changes beginning from around 4 ka cal bp were concordant with the general weakening of the east asian monsoon during the holocene corresponding with an orbitally induced reduction of boreal summer insolation this is the first terrestrial high resolution record from eastern part of middle subtropical areas that evaluates the forest changes through the last glacial interglacial cycle

the last glacial cycle from the humid tropics of northeastern australia comparison of a terrestrial and a marine record a detailed pollen record from the ocean drilling program site 820 core located on the upper part of the continental slope off the coast of northeast queensland was constructed to compare with the existing pollen record from lynch s crater on the adjacent atherton tableland and allow the production of a regional picture of vegetation and environmental change through the last glacial cycle some broad similarities in patterns of vegetation change are revealed despite the differences between sites and their pollen catchments which can be related largely to global climate and sea level changes the original estimated time scale of the lynch s crater record is largely confirmed from comparison with the more thoroughly dated odp record conversely the lynch s crater pollen record has assisted in dating problematic parts of the odp record in contrast to lynch s crater which reveals a sharp and sustained reduction in drier araucarian forest around 38 000 yrs bp considered to have been the result of burning by aboriginal people the odp record indicates most likely a stepwise reduction dating from 140 000 yrs bp or beyond the earliest reduction shows lack of a clear connection between araucaria decline and increased burning and suggests that people may not have been involved at this stage however a further decline in araucarian forest possibly around 45 000 yrs bp which has a more substantial environmental impact and is not related to a time of major climate change is likely at least partially the result of human burning the suggestion from the odp core oxygen isotope record of a regional sea surface temperature increase of around 4 degrees c between about 400 000 and 250 000 yrs bp may have had some influence on the overall decline in araucaria and its replacement by sclerophyll vegetation c 2000 elsevier science b v all rights reserved