sand dunes as a major proximal dust source for late pleistocene loess in the negev desert israel grain size analyses of three hilltop primary eolian loess sequences in the negev desert southern israel show a bimodal grain size distribution at 50 60 m and 3 8 m using analyses of mineralogy and osl ages we demonstrate that the coarse mode is composed mostly of quartz grains and its relative magnitude increases regionally with time suggesting an enhancement of a time transgressive proximal dust source compared to a distal saharan fine grain dust the only proximal dust source for large amount of coarse silt quartz grains is the sands that advanced into sinai and the negev concurrently with the loess accretion during the late pleistocene as a result of the exposure of the mediterranean shelf we therefore propose that the coarse silt quartz grains were formed through eolian abrasion within the margins of an advancing sand sea this relationship between desert sand seas as a source for proximal coarse dust and desert margin loess deposits can be applicable to other worldwide deserts such as northern africa china and australia

eolian quartz flux to lake biwa central japan over the past 145 000 years abstract eolian quartz flux eqf g cm 2 103yr 1 to lake biwa central japan provides direct information on variations of the east asian winter monsoon lake biwa sediments spanning the past ca 145 000 yr are characterized by two main periods when eqf values were significantly greater than 5 50 g cm 2 103yr 1 and two main intervals during which eqf values were lower two periods with eqf values 5 50 g cm 2 103yr 1occurred from ca 145 000 to 125 000 and 73 000 to 13 000 yr b p while times of lower eqf values occurred from ca 125 000 to 73 000 yr b p and around ca 5500 yr b p between ca 125 000 and 73 000 yr b p three minimum eqf values and two intervening peaks of slightly higher eqf values are recorded eqf increased markedly from ca 73 000 to 13 000 yr b p whereas between ca 53 000 and 20 000 yr b p the values recorded were relatively lower than those recorded during either the preceding or the subsequent episodes the data imply that the east asian winter monsoon strengthened during the periods when eqf values were high and weakened during the intervals with low eqf values the eqf record of lake biwa can be correlated with the grain size record of the quartz fraction in chinese loess and with the specmap marine 18o record however the eqf record apparently lags ca 5000 yr behind the loess and 18o records during stage 6 5 and 2 1 transitions and ca 10 000 yr during stage 5 4 transition these apparent lags could be due to problems with the chronology alternatively they may imply that the eolian quartz flux depended more on the extent of dust source regions than on wind intensity during these transitions

holocene vegetation and climate of the alashan plateau nw china reconstructed from pollen data a set of 55 recent pollen spectra from the alashan plateau and the qilian mountains qilianshan northwestern china has been analyzed the established relationships between the pollen spectra and modern vegetation and precipitation patterns of the studied area have been applied to 65 fossil pollen spectra from a 825 cm long sediment record collected in the topographic depression formerly occupied by eastern juyan palaeolake 41 89 n 101 85 e 892 m a s l several qualitative approaches e g indicator plant species artemisia chenopodiaceae and ephedra fragilis type s l ephedra distachya type pollen ratios and quantitative methods of vegetation and climate reconstruction have been tested with the surface pollen and then applied to the eastern juyan pollen record fossil pollen data reveal pronounced environmental changes in the studied area of the alashan plateau between ca 10 700 and 1700 cal yr b p desert taxa as chenopodiaceae nitraria calligonum reaumuria were abundant in the vegetation cover around the study site through the whole record pollen spectra dated to ca 10 700 5400 cal yr b p are characterised by highest values of chenopodiaceae e fragilis type and other desert indicating taxa suggesting rather dry climate most favourable conditions are reconstructed between 5400 and 3900 cal year b p on the basis of relative increase in abundance of artemisia pollen a return to dry conditions occurred at about 3900 cal yr b p the lake finally desiccated after 1700 cal yr b p reconstructed dry climate oscillations between 5900 and 5400 and 3100 cal yr b p correlate well with similar events found in the published records from northern and western china and central mongolia however eastern juyan record does not show the early holocene humidity maximum as suggested by the sedimentary data from monsoon influenced areas of china

evolution of the transport direction of the carpathian belt during its collision with the east european platform the evolution of the carpathians is in its final stage with intermediate seismic activity 70 200 km mw 4 7 7 localized beneath its southeastern salient vrancea zone our analysis in the transition area between south carpathians and east carpathians reveals that the termination of convergence is characterized by a clockwise rotation of the carpathian belt transport direction using structural maps and cross sections we show that this change of convergence direction had several structural consequences including 1 the pliocene quaternary activation of out of sequence structures in the southern east carpathians and 2 the creation of dextral strike slip faults bounding the mobile belt to the west in the south carpathians our fracture analysis in syntectonic deposits allows us to distinguish and stratigraphically date two fanning stress patterns corresponding to the two last transport directions of the carpathian system 1 a burdigalian to early tortonian stress field with compression directions rotating along with the carpathian curved orogenic belt but with transpression nw se compression and a low strain partitioning along east trending internal strike slip faults in the south carpathians and 2 a late tortonian to pleistocene rotated and smaller radial stress pattern with n s compression in the south carpathians the rotation of the convergence direction is interpreted as the result of the miocene migration and progressive collision of the carpathian system with the thick crust of the nw trending tornquist teisseyre line and its prolongation in romania the area able to subduct determined by thickness of crust entering the subduction zone was progressively restricted to a foreland corner in front of the southeastern carpathians the progressive collision forced the convergence to slow down and rotate from eastward to southeastward in late miocene the dobrogea hills in front of the latest migrating system may represent the late neogene ne sw flexural bulge of the subducting foreland panel this clockwise rotation of the transport direction can be compared with the clockwise rotation that occurred in other subduction systems tyrrhenian subduction caribbean subduction etc which were controlled by the location of oceanic versus continental crust in front of the orogenic belt

holocene millennial scale vegetation changes in the yugu floodplain kongju area central south korea abstract to understand vegetation responses to past climate change on millennial timescales the holocene record of floodplain vegetation change in central south korea was reconstructed using the stable isotopic composition 13 c and pollen in buried soils low volume overbank deposition of fine grained alluvium by yugu stream over the past 10 000 years has produced a sequence that is well suited for 13 c analysis of soil organic matter the 13 c values varied between 25 and 20 during the holocene showing significant millennial scale fluctuations in five stages 11 000 8900 cal bp 8900 6100 cal bp 6100 3300 cal bp 3300 1200 cal bp and 1200 cal bp to present the abundance of c 4 plants estimated from a binary mixing model changed from approximately 17 57 during the stages from 3300 to 1200 cal bp and from 8900 to 6100 cal bp c 4 plant abundance and the percentage of arboreal pollen were high but the percentage of spores mainly moss and the freshwater algal sum were low indicating more arid environments temporal comparison of c 4 plant abundance change during the holocene with other reconstructed climate data from east asia suggests that millennial scale vegetation change or aridity change in central south korea was generally more synchronous with regional climate change during the late holocene than during the early to mid holocene this study suggests that the past vegetation in the yugu area has evolved in response to summer monsoon intensity in a non linear manner

late pleistocene continental climate and oceanic variability recorded in northwest pacific sediments core v21 146 provides a continuous record of northwest pacific pelagic sedimentation spanning the past 530 000 years downcore variations of 18o from benthic foraminiferal calcite were correlated to the specmap record to provide an age model for late pleistocene paleoclimatic and paleoceanographic variation fluxes of caco3 and eolian material have been determined by combining information about linear sedimentation rates bulk densities and component percentages the mass accumulation rate mar of caco3 varies from 58 to 1435 mg cm kyr 1 and exhibits the pacific ocean pattern of higher accumulation associated with glacial periods for the younger portion of the record however the pattern of caco3 accumulation appears to shift during the mid brunhes so that prior to 350 000 years ago it exhibits an opposite pattern of greater accumulation during interglacial periods the flux of eolian dust is a proxy measure of the source area aridity and correlates well to the loess soil stratigraphy in china dust fluxes range from 43 to 718 mg cm kyr 1 and are greater by a factor of about 4 during glacial times cross spectral analysis of the eolian flux and oxygen isotope records shows an inphase and coherent relationship at each of the major orbital periodicities of 100 41 and 19 kyr eolian grain sizes generally used as a proxy record of wind intensity range from 8 4 2 9 m to 6 2 13 6 m a change in grain size variability occurs near about 300 ka such that the older portion is characterized by lower frequency and higher amplitude fluctuations than the younger portion power spectra for the eolian grain size record show dominant peaks at 100 and 50 kyr and a broad 25 35 kyr peak but coherency to the oxygen isotope curve at only the 100 and 33 kyr periodicities the phase relationship for eccentricity between the eolian grain size and 18o records suggests that at the 100 kyr frequency the smallest grain sizes are associated with glacial conditions

origin and weathering properties of loess paleosol sequence in the goseong area on the east coast of south korea abstract this study aims to investigate the origin and weathering properties of the loess paleosol sequence in the goseong area on the east coast of south korea and to discuss the local sediment inputs and their paleoclimatic implications the geochemical properties suggest that the largest proportion of the sequence originated from the chinese loess plateau and or its source areas with a smaller quantity originating from the weathering products of the bedrock around the section although its origin can be regarded as the chinese loess plateau and or its source areas the sequence shows more weathered features than the chinese loess plateau moreover the weathering environments in south korea were different from those in the chinese loess plateau the difference in weathering properties may be attributed to the more humid climatic conditions in south korea the abundance of local sediment input to the sequence was controlled by sea level fluctuations in the east sea of korea and the global ice sheet developments during the glacial and interglacial cycles in the quaternary because local sediment occupies only minor proportions in the sequence the monsoon and westerly circulations in northeast asia played an important role in the loess formations in south korea as well as in the chinese loess plateau

grain size and accumulation rate records from late cenozoic aeolian sequences in northern china implications for variations in the east asian winter monsoon and westerly atmospheric circulation we attempt to reconstruct the history of westerly and monsoonal circulations in northern china using variations in sediment grain size and accumulation rate at four loess sections in the central chinese loess plateau the initiation of aeolian accumulation at about 7 6 ma in the main part of the chinese loess plateau probably marked the onset of the monsoonal circulation both the monsoonal and westerly circulations weakened from 7 6 to 5 2 ma subsequently the monsoonal circulation strengthened progressively from 5 2 ma to the present in addition the westerly circulation strengthened from 5 2 to 0 6 ma but then weakened thereafter and especially during the last 0 6 ma comparison of our aeolian records and the deep sea sediment record suggests that the strengthening trends of the monsoonal and westerly circulations were associated with the progressive development of global ice sheets during the late cenozoic abrupt changes of both the monsoon and westerly circulations occurred at 7 6 3 4 and 1 2 0 9 ma together with a weakening trend of the westerly circulation in the last 0 6 ma and are interpreted as the consequence of the episodic uplift of the tibetan plateau spatial differences in the grain size characteristics amongst the four sections suggest that the circulation intensity and variability decreased from west to east across the loess plateau due to the topographic effect of the tibetan plateau in addition some spatial differences may have been the result of local topographic effects c 2008 elsevier b v all rights reserved

a platform to basin transition for lower aptian carbonates shuaiba formation of the northeastern jebel akhdar sultanate of oman abstract the platform to basin transition of the lower aptian shuaiba carbonate platform throughout a large part of the arabian peninsula has hitherto mainly been documented from subsurface data and has widely been regarded as having been progradational in northeastern jebel akhdar however the shuaiba platform did not prograde and was scarp bounded early lithification accounts for the rigid nature of the scarp a biological framework being nearly absent early exposure surfaces neptunian dykes sills internal breccias and other sediment features as well as the geographic coincidence of the platform scarp with older and younger scarps suggest a tectonic control of margin morphology and dynamics a contemporaneous peak of allodapic sediments and reactivation of older basement structures in adjacent basins also tends to indicate the importance of structural influence on platform margin organization

groundwater discharge to a gobi desert lake during mid and late holocene dry periods abstract high levels of lake eastern juyanze and a wetter climate in the gobi desert nw china were recorded between 5100 and 4100 cal year bp from ostracod distribution shell geochemistry sedimentology and palynological data after about 4100 cal year bp lake levels decreased and groundwater discharge became dominant source of water during short term regressive events at about 4000 3800 and 3500 cal year bp as suggested by a significant difference in modern river water and groundwater chemistry and the geochemical signal of fossil ostracod shells the overall trend towards lower lake levels culminated in repeated episodes of desiccation of lake eastern juyanze between 3200 and 2900 cal year bp individual regressive events as well as the rapid environmental fluctuations of lake eastern juyanze at about 3000 cal year bp were likely caused by mid to late holocene temperature fluctuations recorded by the dunde ice core yao t thompson l g 1992 trends and features of climatic changes in the past 5000 years recorded by the dunde ice core annals of glaciology 16 21 24 and shifts of the southeastern asian monsoon

reconstructing dust storm frequency in china since 1617 ce using coral based estimates of sea surface temperature abstract dust storms occur frequently in arid and semi arid regions of china and other parts of the world exerting a considerable influence on air quality in densely populated areas instrumental observations of dust storms are only available over the past 50 to 60 years limiting our ability to understand dust storm variability over longer timescales however tropical sea surface temperatures have been reconstructed over the past four centuries using geochemical records from corals here we show that tropical pacific sea surface temperatures as recorded by corals can be used to reconstruct dust storm frequency at one year resolution based on the coral reconstructed annual sea surface temperature anomaly data from two regions the western pacific 25 n 25 s 110 155 e and the eastern pacific 10 n 10 s 175 e 85 w published by tierney et al 2015 we reconstructed the frequency of dust storms in northern china dsfcn for the period from 1617 to 1953 ce the reconstructed dsfcn variation can be divided into several distinct periods 1 dsfcn increased from 1617 to 1650 then 2 decreased from 1650 to 1675 3 remained unchanged from 1675 to 1755 4 increased again from 1755 to 1860 5 remained unchanged from 1860 to 1925 and finally 6 decreased rapidly from 1925 to 1995 we propose the following causal chain to explain the observed relationship between dsfcn and sst as tropical pacific ocean sst increases the siberian high weakens and the eastern asian trough strengthens as the air pressure difference weakens the east asian winter monsoon weakens and strong wind frequency decreases causing dsfcn to decrease as well the statistical results support this interpretation of the causal chain

middle holocene environmental change in central korea and its linkage to summer and winter monsoon changes to trace the surficial responses of lowlands to past climate change we investigated 13c in total organic carbon toc c n ratios magnetic susceptibility ms and silicon si intensity directly proportional to concentration in wetland sediments collected from the gimpo area of central korea covering 6600 4600 cal yr bp two organic layers with high toc negatively depleted 13ctoc values 27 to 29 low ms values and low si intensities were found at 6200 5900 and 5200 4800 cal yr bp respectively these middle holocene wet periods corresponded to relatively intensified summer monsoon and solar activity periods the intervening dry period 5900 5200 cal yr bp with high ms high si and low toc corresponded to an intensified dust activity interval and stronger winter monsoon this multi centennial climatic fluctuation of wet periods 6200 5900 cal yr bp and 5200 4800 cal yr bp and an intervening dry period 5900 5200 cal yr bp in central korea was more synchronous with climate change in the arid inner part of china than with that in south china suggesting possible strong high latitude driven climatic influences e g north atlantic cooling events during the middle holocene

provenance of loess material and formation of loess deposits on the chinese loess plateau abstract results of a multiple isotopic chemical and mineralogical analysis of loess from the three northwestern inland basins the junggar basin the tarim basin and the qaidam basin and the loess plateau region of china are summarized they suggest a qualification of the conventional views that the three northwestern basins were the important source areas of the loess plateau and that the sand deserts were the primary single source of the chinese loess it is argued that the gobi stony desert in southern mongolia and the adjoining gobi and sand deserts the badain jaran desert tengger desert ulan buh desert hobq desert and mu us desert in china rather than the three inland basins are the dominant source areas of the loess plateau however although these gobi and sand deserts are regarded as the main source regions they serve as dust and silt holding areas rather than dominant producers the mountain processes including glacial grinding frost weathering salt weathering tectonic processes and some fluvial comminution in the gobi altay mts hangayn mts and the qilian mts have played an important role in producing the vast amounts of loess sized material for forming the loess plateau

fine aeolian quartz records in cheju island korea during the last 6500 years and pathway change of the westerlies over east asia 1 we investigated the fine component of aeolian dust deposited on a maar of cheju island korea during the last 6500 years to specify the variability of fine aeolian dust transported by the westerlies and its main controlling factor from the viewpoint of global atmospheric circulation as a proxy for the fine aeolian dust we used the fine component of chemically isolated aeolian quartz from bulk sediments the fine quartz flux fqf varies from 0 1 to 1 4 mg cm2 a with periodicities of 1620 810 400 325 and 210 years mainly providing information on the aridity change in the dust source region the taklimakan desert the median grain size of the fine quartz mfq representing the pathway of the dust transporting westerlies fluctuates between 2 and 6 m with significant cycles of 1030 390 280 220 and 195 years and shows similar variation pattern to the fqf on the basis of visual and spectral analyses the high low fqf and the large small mfq correspond to the warm cold atmospheric temperature record from greenland ice cores with significant coherent cycles indicating that the aridity in the dust source areas and the pathway of the westerlies in east asia were linked to climatic and atmospheric conditions in greenland through the pathway change of the westerlies during the middle to late holocene the pathway change of the westerlies mainly responsible for the variability of the fine aeolian dust in east asia was probably controlled by a climatic response to initial solar activity and resulting atmospheric reorganization in polar and high latitude regions

thermo mechanical controls on the mode of continental collision in the se carpathians romania abstract the carpathians orogenic system with its along arc variations in topography developed in the aftermath of continental collision is associated with unusual foredeep basins large scale strain and seismicity concentration and high velocity mantle bodies the east carpathians continental collision was non cylindrical leading to large scale variations in thrust nappe kinematics orogenic uplift patterns and foredeep subsidence controlled by the mechanics and geometry of the lower plate thermo mechanical modelling demonstrates that in this low rate convergence regime the subducted lithosphere had enough time to interact with the mantle to advance towards a thermal resettlement this is favored by the low degree of metamorphism mechanical weakness of the lower plate and the lack of active surface processes at the contact with and in the upper plate in contrast low buoyant thick lower crust and active surface processes keep the continuity of the slab intact and promote the development of typical foredeep basins the model explains in a self consistent manner the unusual geometry of the vrancea seismogenic slab in the bend zone of the romanian carpathians the model is also consistent with the presence of two high velocity bodies inferred from seismic tomography studies and explains the depth zonation of seismicity in the vrancea area differences between the northern part of east carpathians and the southeastern bend of the carpathians arc are largely controlled by lateral variations in crustal structure topography emplacement and surface processes along the arc mechanical heterogeneity of the carpathians subduction leads to the development of two end member modes of collision allowing a study of these states and their transition lithospheric configuration and tectonic topography appear to be prime factors controlling variations in slab behavior in the se carpathians at the terminal phase of continental convergence slab delamination roll back and depocenter migration appear to play a more limited role at shallow and lithospheric levels

tertiary tectonic evolution of the external east carpathians romania abstract paleostress calculation and analysis of mesoscopic structures are integrated with depth interpreted geological profiles based on seismic studies and well correlation to derive a tertiary tectonic model for the east carpathians following early miocene and older orogenic phases the first tectonic event that affected the studied area is characterised by a wsw ene oriented shortening of middle miocene late burdigalian in age resulting deformations induced ene ward thrusting of tarcau and marginal units as well as the internal part of the subcarpathian nappe a second shortening event with an e w to wsw ene contraction direction took place in the late miocene sarmatian characterised by further foreland thrusting of the subcarpathian nappe and out of sequence deformation in the tarcau and marginal folds nappes along strike differences in deformation mechanisms are controlled by the friction coefficients along the main detachment layers by the lateral variations in the wedge thickness and by the involvement in the northern part of the thrusting system of the thick competent east european platform tear faulting occurred in both tectonic events the main resulting structure being the triangle zone developed south of the trotus valley the latest miocene latest sarmatian early pliocene is characterised by a strike slip stress field with nne ssw compression and wnw ese tension axis left lateral faults being dominant the last deformation which affected the studied area is characterised by nnw sse shortening during the pliocene major deformations taking place mainly in the sw most bending zone

the neogene evolution of the outer carpathian flysch units poland ukraine and romania kinematics of a foreland fold and thrust belt system abstract various techniques of geometric and kinematic analyses including cross section balancing and forward modeling have been applied successfully to the outer carpathian flysch units along regional geologic profiles crossing the belt from its undeformed foreland to the pieniny klippen belt western carpathians poland or to the central east carpathian allochthon eastern carpathians ukraine and romania the amounts of neogene shortening as well as the mode and the location of basement consumption are discussed on the basis of balanced cross sections compiled along the three most representative regional traverses in addition the complete kinematic evolution of complex carpathian structures such as the fore dukla triangle zone southeastern poland the borislav pokut duplexes ukraine and the marginal folds romania are described in more detail by using a forward modeling approach major results concern the tectonic heritage of laramian inverted structures mesozoic normal faults reactivated as reverse faults during the late cretaceous paleocene compression or transpression in the development of the neogene outer carpathian edifice pre eocene deformation and erosion effectively induce discontinuities in the mid cretaceous blackshale detachment horizon and help to localize the neogene deformations in complex triangle zones the thrust sequence itself evolves alternatively in a piggyback or in an out of sequence mode clearly the critical taper of the outer carpathians is preserved by a constant balance between erosion and thrust reactivations in the inner part of the wedge and sedimentation and tectonic accretion at its front

dust records from varved lacustrine sediments of two neighboring lakes in northeastern china over the last 1400 years dust storms are natural phenomena described in chinese historical documents as early as 1150 bc these documents provide a way to evaluate proxy data from different natural records the minerogenic clastic content and grain size from two closed maar lakes located a short distance apart in northeastern china were analyzed the area is located in the path of dust storms the minerogenic clastics in the studied maar lakes originate mainly from dust deposition general variations of the minerogenic clastic content in these two neighboring lakes show a good coincidence with dust concentration in a tibet ice core and dust events as recorded in historical documents the minerogenic clastic content in the lake sediments is linked with the climate conditions in the dust source regions and wind strength three periods of intensive dust events ad 1050 1330 ad 1590 1690 and the last 200 years have been identified during the past 1500 years the recent increasing pattern of clastic content could be linked to human activity in the dust source regions significantly most of the medieval warm period mwp was marked by a high frequency of dust storms

holocene dust deposition in the ili basin and its implications for climate variations in westerlies dominated central asia abstract understanding holocene paleoclimate in arid central asia aca is helpful for predicting future climate however holocene climate patterns and their forcing mechanisms across aca are vigorously debated in the context of global climate change here we present a holocene loess profile sgx from the ili basin in the westerlies dominated central asia based on high resolution medium grained 38 63 m quartz optically stimulated luminescence osl dating and grain size and color measurements we reconstruct the holocene paleoclimate osl geochronology indicate that this sgx loess profile covers the last 11 5 ka and grain size analyses reveal that the sediments are sandy loess and the environmentally sensitive fractions are

vrancea99 the crustal structure beneath the southeastern carpathians and the moesian platform from a seismic refraction profile in romania the vrancea99 seismic refraction experiment is part of an international and multidisciplinary project to study the intermediate depth earthquakes of the eastern carpathians in romania as part of the seismic experiment a 300 km long refraction profile was recorded between the cities of bacau and bucharest traversing the vrancea epicentral region in nne ssw direction the results deduced using forward and inverse ray trace modelling indicate a multi layered crust the sedimentary succession comprises two to four seismic layers of variable thickness and with velocities ranging from 2 0 to 5 8 km s the seismic basement coincides with a velocity step up to 5 9 km s velocities in the upper crystalline crust are 5 9 6 2 km s an intra crustal discontinuity at 18 31 km divides the crust into an upper and a lower layer velocities within the lower crust are 6 7 7 0 km s strong wide angle pmp reflections indicate the existence of a first order moho at a depth of 30 km near the southern end of the line and 41 km near the centre constraints on upper mantle seismic velocities 7 9 km s are provided by pn arrival times from two shot points only within the upper mantle a low velocity zone is interpreted travel times of a plp reflection define the bottom of this low velocity layer at a depth of 55 km the velocity beneath this interface must be at least 8 5 km s geologic interpretation of the seismic data suggests that the neogene tectonic convergence of the eastern carpathians resulted in thin skinned shortening of the sedimentary cover and in thick skinned shortening in the crystalline crust on the autochthonous cover of the moesian platform several blocks can be recognised which are characterised by different lithological compositions this could indicate a pre structuring of the platform at mesozoic and or palaeozoic times with a probable active involvement of the intramoesian and the capidava ovidiu faults especially the intramoesian fault is clearly recognisable on the refraction line no clear indications of the important trotus fault in the north of the profile could be found in the central part of the seismic line a thinned lower crust and the low velocity zone in the uppermost mantle point to the possibility of crustal delamination and partial melting in the upper mantle

a lacustrine record of east asian summer monsoon and atmospheric dust loading since the last interglaciation from lake xingkai northeast china a 336 cm long sediment core spanning the last 130 ka was recovered from lake xingkai on the northeastern margin of the east asian summer monsoon domain to reveal the linkage between lacustrine depositional processes and environmental changes bayesian end member modeling analysis was conducted to partition and interpret the grain size distributions of lake xingkai sediments our results suggest that the sedimentary system is characterized by three end members ems em1 and em2 with a modal value of 13 and 10 m respectively indicate the variation of local hydraulic conditions em3 with a modal value of 5 m reflects the background atmospheric dust loading high atmospheric dust concentration generally occurred during marine isotope stage mis 5d mis 4 and early mis 3 when the climate in the asian dust source region was cold and dry in contrast low dust concentration prevailed during mis 2 likely due to the southward shift of the westerlies driven by maximum ice volume in the high latitudes

architecture of the focsani depression a 13 km deep basin in the carpathians bend zone romania 1 in front of the se carpathians bend a very deep basin focsani depression developed in miocene to recent times an important part of its subsidence occurred after the main stages of thrusting in the carpathians apparently the basin lies in the wrong place and evolved in the wrong time in this study we constrain its architecture and evolution by analyzing a large database consisting of more than 1000 km two dimensional seismic lines and more than 60 wells around 13 km thick badenian to quaternary 16 5 myr sediments were deposited in the central part of the focsani depression during the badenian 16 5 13 myr the foreland south of trotus fault underwent ne sw directed extension and nw trending basins opened in the eastern moesian platform a nw se oriented area of subsidence stretched from the transylvania basin through the focsani depression to the se of the moesian platform while thrusting was going on in the east european scythian platform east carpathians and getic depression starting with the sarmatian 13 10 myr the focsani depression depocenter moved out of the carpathian belt coeval with the exhumation of the south and the east carpathians north of the trotus fault the basin became wider and was tilted toward the belt tilting was accompanied by dextral shearing mainly along the intramoesian and peceneaga camena faults after sarmatian times subsidence occurred practically only sse of trotus fault during meotian pontian 10 5 myr subsidence slowed down stronger pliocene quaternary subsidence is coeval with normal faulting and shearing in moesian platform the western margin of the focsani depression was then tilted eastward coeval with the exhumation of the bend zone and opening of the intramontane basins in the inner part of the belt

bimodal grain size distribution of aeolian quartz in a maar of cheju island korea during the last 6500 years its flux variation and controlling factor 1 aeolian quartz chemically isolated from maar sediments in cheju island korea showed bimodal grain size distributions after partitioning into fine and coarse components fine and coarse quartz fluxes fqf and cqf were calculated the average median grain size of fine quartz was 3 m and the average fqf was 0 5 mg cm2 yr with a range of 0 1 1 6 mg cm2 yr during the last 6500 years the average cqf was 3 mg cm2 yr with a range of 1 5 5 mg cm2 yr and its average median grain size was 15 m comparisons of our results with the present aeolian dust activities and climate changes in dust source areas suggest that fqf was influenced by the pathway of the westerlies between taklimakan desert and cheju island while cqf was affected by the aridity in the source regions including the gobi desert in southern mongolia and the adjoining gobi and sand deserts in china during the last 6500 years

late quaternary dust flow on the chinese loess plateau abstract the dust flux of over 25 g cm2 103yr was reached in the central part of the chinese loess plateau during the last glacial maximum this is more than three times higher than during the last interglacial and early glacial time the grain size of the pleniglacial dust reached a peak shortly after 20 000 years ago and testifies to the occurrence of strong winds and frequent dust storms

grain size of quartz as an indicator of winter monsoon strength on the loess plateau of central china during the last 130 000 yr the chinese loess paleosol sequence constitutes an important record of variations in asian monsoon climate over the past 2 4 myr magnetic susceptibility of loess and paleosols has been used as a proxy for summer monsoon intensity while median grain size has been regarded as a measure of the strength of winter monsoon winds that were responsible for most of the dust transport however median grain size is only an approximate index of winter monsoon strength because both paleosols and loess have been modified to various degrees by weathering processes that have produced pedogenic clay the quartz component of loess and paleosols is largely unaffected by weathering processes and therefore constitutes a more reliable proxy index of monsoon wind strength median grain size qmd and maximum grain size qmax values of monomineralic quartz isolated from the loess paleosol section at luochuan in the central loess plateau are characterized by two main intervals during the last ca 130 000 yr when these parameters were significantly greater than 9 and 85 m respectively and three main intervals when they were lower the data imply that the winter monsoon weakened during the intervals with low qmd and qmax values which coincide with marine oxygen isotope stages 5 3 and 1 and was strongest ca 67 000 and 20 000 yr ago during isotope stages 4 and 2 however both quartz grainsize records display second order high frequency high amplitude variations which are lacking in the magnetic susceptibility record that imply rapid and significant changes in atmospheric conditions that affect dust transport and deposition

kinematics of an arcuate fold thrust belt the southern eastern carpathians romania abstract flysch and molasse nappes of the eastern carpathians strike mainly n s and were folded and imbricated since the late early cretaceous boundaries of stratigraphic and structural units and calculated fold trend axes from the southern part of the eastern carpathians indicate a curvature of the orogen by 80 kinematic data from fault slip analysis of all nappe systems exposed in the arc document an overall nw se contraction nappes of the external moldavides nappe complex underwent deformation since the late cretaceous peaking in the miocene and exhibit fanning subhorizontal contraction axes from e w in the n striking part of the eastern carpathians through wnw ese and nw se in the northern part of the arc to nnw sse in its southwestern part geometric relations between faults and folds indicate that this fan pattern reflects an extended interval and was contemporaneous to nappe stacking and subsequent continental collision statistical analysis reveals correlation between orientation of the fanning kinematic axes and the structural trend where fanning of subhorizontal contraction axes is systematically smaller than change of strike of fold thrust structures orogen parallel extension in the tarcau nappe of the moldavides nappe complex is estimated to be 20 this low value of orogen parallel extension indicates a primary arc in contrast to bending of a previously straight fold thrust belt low orogen parallel extension and the observed pattern of structural and kinematic axes can be simulated in sand wedge indentation models where the indenter moves oblique to its margins in these models thrust traces and fold axes are curved around the arc but are parallel to the margins of the indenter away from the corner area the movement directions of the thrust faults in the models are deflected from normal to fault strike towards the movement direction of the indenter leading to fanning contraction directions similar to those observed in the eastern carpathian arc thus the main controlling factors on arc formation were the plate margin geometry i e the shape of the upper plate and the movement direction of the upper plate relative to the orientation of its margins the influence of the geometry of the continental margin in the lower plate was mainly by imposing constraints on the movement direction of the upper plate

3 d upper crustal tomographic structure across the vrancea seismic zone romania abstract the vrancea99 and vrancea2001 seismic refraction experiments are part of a multidisciplinary project to study the eastern carpathians in romania the objectives of these studies are intended to disclose a more detailed picture of the crustal and upper mantle structures above the seismically active vrancea region in this paper we provide additional constraints for the upper crustal structures of the area the 1999 campaign consisted of a 320 km long n s profile and a 70 km long e w profile the intersecting 2001 profile extended in e w direction from the hungarian border to the black sea in order to enhance the model resolution first arrival data from local crustal earthquakes were also included this configuration allowed for the first time to derive a 3 d velocity model for the upper crust of the romanian carpathian orogen within a 115 235 km wide region centred over the vrancea seismic zone the 3 d model reveals lateral velocity variations which were not visible on the in line interpretations it allows us to distinguish between foreland platform areas foreland basins and the carpathian orogen clear velocity differences between the foreland basins south and southeast of the eastern carpathians and the focsani basin further north indicate different pre miocene sedimentary compositions and geological evolutions of these foreland platforms the involved moesian and scythian platforms are separated by the trotus fault system which is observed as a velocity discontinuity an upper crustal high velocity zone above the northern vrancea seismic zone could also be identified this high velocity zone is explained by a middle pliocene to pleistocene e w oriented out of sequence thrust of the crystalline basement below the decollement of the flysch nappes

defining the quaternary abstract the quaternary system is under threat of extinction as a chronostratigraphic unit in the international geological time scale in its place the neogene system previously comprising miocene and pliocene series is to be extended to include the pleistocene and holocene series it may be possible to save the quaternary by defining it as a subsystem of the neogene in doing so it would be an opportune time to extend the base of the quaternary to 2 6 ma to encompass the time during which 1 earth s climate has been strongly influenced by bi polar glaciation and 2 the genus homo first appeared and evolved

mineralogy of aeolian dust reaching the north pacific ocean 1 sampling and analysis the mineral composition of the 2 m clay and 2 to 20 m silt size fractions of aerosol particles collected near the margins of the north pacific ocean was determined by x ray diffraction analysis although the same mineral phases are present in the two size fractions there are significant differences in the quartz plagioclase and kaolinite concentrations north pacific aerosols are primarily composed of illite in both size fractions in addition to kaolinite in the 2 m size class and quartz and plagioclase in the 2 to 20 m size class quartz and plagioclase are present in significantly higher amounts in the 2 to 20 m size fraction while kaolinite is greater in the 2 size class western north pacific aerosol particles contain significantly higher 2 m quartz than samples collected in the east and eastern north pacific aerosols have significantly higher concentrations of 2 m smectite than those from the west

complexity of holocene climate as reconstructed from a greenland ice core glaciochemical time series developed from summit greenland indicate that the chemical composition of the atmosphere was dynamic during the holocene epoch concentrations of sea salt and terrestrial dusts increased in summit snow during the periods 0 to 600 2400 to 3100 5000 to 6100 7800 to 8800 and more than 11 300 years ago the most recent increase and also the most abrupt coincides with the little ice age these changes imply that either the north polar vortex expanded or the meridional air flow intensified during these periods and that temperatures in the mid to high northern latitudes were potentially the coldest since the younger dryas event

asian dust transport during the last century recorded in lake suigetsu sediments asian dust has a significant impact on the natural environment its variability on multiple timescales modulates the ocean biogeochemistry and climate we demonstrate that temporal changes in the deposition flux of aeolian dust recorded in sediments from lake suigetsu central japan during the last century exhibit a continuous decreasing trend and a decadal scale decrease in 1952 1974 the former decreasing trend can be explained by a decrease in the dust storm frequency at source regions due to the warming of mongolia in the twentieth century suggesting future decrease of asian dust transport with further warming in mongolia decadal scale decrease of aeolian dust is explained by weaker westerlies in lower latitudes in central japan reflecting a weaker aleutian low during the corresponding period decadal scale westerly change probably causes north south shifts of the dominant dust transport path which affects subarctic northern pacific ocean biogeochemistry by changing the micronutrient iron supply

late miocene quaternary volcanism tectonics and drainage system evolution in the east carpathians romania abstract middle miocene sarmatian convergence created the fold and thrust belt of the eastern carpathians of romania which subsequently experienced post collisional crustal deformation combined with calc alkaline and alkalic basaltic volcanism in late miocene quaternary time this deformation led to the rise of the c limani gurghiu harghita volcanic mountains and to the subsidence of the n s oriented intramontane borsec bilbor gheorgheni ciuc and brasov pull apart basins and the e oriented monocline related f g ras basin the regional drainage network is the composite of 1 older e se and s flowing rivers which cross the carpathians radiate towards the foreland and were probably established during the middle miocene sarmatian collision event 2 a more recent drainage system related to the contemporaneous development of the volcanoes and intramontaneous basins which generally drains westward into the transylvanian basin since late miocene time and has been capturing the older river system the older river drainage system has also been modified by late pliocene quaternary folding thrusting and monoclinal tilting along the pericarpathian orogenic front and by reactivated transverse high angle basement faults which cross the eastern carpathian foreland

paleostress characterization of the wallachian phase in its type area southeastern carpathians romania abstract the wallachian phase is defined in the east carpathians a convex to the east mountain belt in romania as a tectonic event occurring between pliocene and quaternary times this event formed folds and minor thrusts structures that are usually located in internal parts of the somewhat older fold and thrust belt structure this location contrasts with the location one would predict from their recent age and contrasts with the older cretaceous middle tortonian piggyback thrust mode of propagation in the southeastern carpathians this late overstep sequence of thrusting resulted from a modification in the stress field our data indicate that the direction of compression changed from nw se to n s during middle tortonian time this is further supported by stratigraphic dating of structures and thereby paleostresses indicating that the wallachian episode was not a brief event at the pliocene quaternary boundary but lasted from middle tortonian to early pleistocene

late pliocene quaternary tectonics in the frontal part of the se carpathians insights from tectonic geomorphology abstract the romanian east carpathians display large scale heterogeneities along the mountain belt unusual foredeep geometries significant post collisional and neotectonic activity and major variations in topography mostly developed in the aftermath of late miocene sarmatian 11 ma subduction underthrusting and continental collision between the east european scythian moesian foreland and the inner carpathians tisza dacia unit in particular the se corner of the arcuate orogenic belt represents the place of still active large scale differential vertical movements between the uplifting mountain chain and the subsiding focsani foredeep basin in this key area we have analysed the configuration of the present day landforms and the drainage patterns in order to quantify the amplitude timing and kinematics of these post collisional late pliocene quaternary vertical movements a river network is incising in the upstream a high topography consisting of the external carpathians nappes and the pliocene lower pleistocene sediments of the foreland further eastwards in the downstream this network is cross cutting a low topography consisting of the middle pleistocene holocene sediments of the foreland geological observations and well preserved geomorphic features demonstrate a complex succession of geological structures the late pliocene holocene tectonic evolution is generally characterised by coeval uplift in the mountain chain and subsidence in the foreland at a more detailed scale these vertical movements took place in pulses of accelerated motion with laterally variable amplitude both in space and in time after a first late pliocene uplifting period subsidence took place during the earliest pleistocene resulting in a basal quaternary unconformity this was followed by two quantifiable periods of increased uplift which affected the studied area at the transition between the carpathians orogen and the focsani foreland basin in the late early pleistocene and the late middle to late pleistocene both large scale deformation events affected the western focsani basin flank tilting the entire structure with 9 during the late early pleistocene and uplifted it as a block during the early late pleistocene the late early pleistocene tilting resulted in 750 m uplift near the frontal monocline and by extrapolation in a presumed 3000 m uplift near the central parts of the carpathians the late middle to late pleistocene cumulative uplift reaches 250 m and correlates with a contemporaneous progradation of the uplifted areas towards the focsani basin the uplifting events are separated by a second quaternary unconformity on the whole the late pliocene quaternary evolution of the carpathians orogen focsani basin structure indicate large scale differential uplift during the latest stages of a continuous post collisional orogenic evolution

late pleistocene and holocene aeolian dust deposition in north china and the northwest pacific ocean abstract rates of dust deposition in the north pacific and the central loess plateau of china show a poor correlation during the last 30 000 yr although in both cases the dust was derived from deserts in northern china loess accumulation rates were high at the time of the last glacial maximum while dust flux to the north pacific was low at this time maximum dust flux to the north pacific is recorded in the mid holocene but holocene rates of loess accumulation have been low these differences are shown to reflect the different nature of the wind conditions responsible for dust transport to the loess plateau and the north pacific dust transport responsible for formation of the loess occurred mainly in the lower 1 5 km of the atmosphere and was accomplished by cold low level northwesterly winds associated with cold waves emanating from the mongolian anticyclone at present such conditions occur quite frequently in winter but during the coldest phases of the pleistocene they probably also occurred in the spring and summer long range dust transport from northern china to the north pacific requires that the dust is lifted to high levels above 3 km where it can be incorporated into the strong mid latitude westerlies strong vertical motions of the atmosphere occur most frequently in the spring when the mongolian anticyclone begins to weaken and frontal depressions move across the deserts of northern china such frontal depressions were probably more frequent during the climatic optimum of the mid holocene and during previous interglacials changes in continental aridity have probably played a minor role in controlling the magnitude of the dust flux to the north pacific

late pleistocene vegetation change in korea and its possible link to east asian monsoon and dansgaard oeschger d o cycles abstract late pleistocene carbon isotope 13c records from a paleolithic sedimentary sequence collected from baeki hongcheon central korea show long term changes with superimposed short term isotopic excursions the 13c value of the sedimentary organic matter a proxy for past vegetation change varied from 26 to 23 for the period between 30 and 90 ka with a long term variation similar to insolation changes high amplitude 1 to approximately 1 5 fluctuations superimposed on the long term changes in the 13c values decreased during stronger summer monsoon intervals but increased during the weakened summer monsoon this millennial scale pattern is generally similar to greenland dansgaard oeschger d o cycles the possible connection between the hongcheon area korea and high latitudes may be explained by atmospheric circulation changing in response to the d o oscillations in the northern hemisphere

grain size partitioning in loess paleosol sequence on the west coast of south korea using the weibull function abstract this study aims to partition the grain size of the loess paleosol sequence on the west coast of south korea and investigates the limitations and applicability with the partitioning method through the help of a laser diffraction grain size analyzer two to four components depending on the samples and theories employed to convert the laser diffraction data to grain size data are identified through the partitioning process however the identification of one component is thought to be contingent upon the theories employed rather than natural processes the partitioning results reveal that the sequence consists mostly of fine and coarse components transported by the same mechanisms as in the chinese loess plateau and shares common source areas with the chinese loess plateau the sequence also contains a small quantity of material from the local sources and this component is expected to provide crucial information about paleoclimatic variations in korea this study suggests that considerations of the theories are essential in modeling processes of grain size because the theories greatly influence the results of grain size analysis and the number of components and that conversions using the fraunhofer approximation seem to provide more reliable results than those using the mie theory

last glacial aeolian landforms and deposits in the rhone valley se france spatial distribution and grain size characterization abstract in the rhone valley a north south oriented cenozoic rift in southeast france thick pleistocene loess deposits have been recognized since the beginning of the last century these loess records which are disconnected from the north european loess belt nelb are of significant interest to document the evolution of perimediterranean landscapes and environments during the last glacial to overcome the poor precision of available aeolian distribution maps aeolian deposits were mapped using the topsoil textural database provided by the land use and cover area frame statistical survey project lucas the grain size distribution of aeolian sand and loess was first determined using 116 samples taken from surveyed outcrops then the areas showing a similar grain size composition were extracted from the lucas rasters the resulting map reproduces the conventional maps correctly but suggests a more significant extension of loess in better agreement with the known distribution of outcrops the map shows that the distinctive morphology of the valley dominantly controls the distribution of aeolian deposits the deflation related landforms i e yardangs closed depressions pans and desert pavements are widespread south of narrowings of the rhone valley between latitudes 44 n and 45 n they indicate palaeowinds blowing from the north northwest aeolian sand loessic sand sandy loess and loess deposits successively spread on both sides of the rhone river the loess is characterized by a coarse texture main mode around 60 m strong local thickness 5 m limited extension and abundant bioturbation this preservation results from the persistence of a shrub vegetal cover during the coldest and driest phases of the last glacial that allowed for trapping the saltating and suspended particles close to the alluvial sources

the eolian origin of silty mantle in sedentary soils from korea and japan abstract the concentration particle size distribution and oxygen isotope composition 18 o smow of quartz were examined in order to determine the extent to which the accretion of long distance eolian dusts from the interior of china had formed the sedentary soils overlying diverse parent materials in korea and japan the quartz content of the surface soils developed on quartz free basaltic materials varies from 8 9 to 47 7 generally the soil quartz found in surface horizons is finer than of the subsurface horizons and or substrata the particle size of the soil quartz decreases from the west coast to eastern coastal margins of korea and to the japanese islands this follows the major trajectory of westerly winds which carry the eolian dusts from the interior of china to mid latitude regions of the north pacific the oxygen isotope composition of the fine quartz 1 10 m in diameter when separated from surface and subsurface horizons is found in a relatively narrow range of 15 9 to 17 7 the values are indiscernible from those of recent eolian dusts from the interior desert and loess plateau of china the 18 o values from the same sized quartz found in c horizons 10 4 and 19 2 consisting of saprolitic andesites and shales respectively differ from those of the overlying soils the 18 o values of soil quartz developed on igneous materials systematically decrease with increasing particle size to 53 m 14 they abruptly decrease to 8 to 12 for fractions larger than 53 m a large apparent oxygen isotope fractionation up to 10 between fine 17 and coarse 8 to 12 grained quartz observed in the samples does not represent an equilibrium oxygen isotope fractionation for normal magmatic processes the data provide evidence for an eolian origin of the fine quartz incorporated during soil development

eolian quartz flux variations in cheju island korea during the last 6500 yr and a possible sun monsoon linkage we have obtained a high resolution sedimentary record covering the last 6500 yr from a maar in cheju island korea in order to reconstruct the history of variations in the eolian quartz flux eqf and hence asian dust the long term variation of eqf reveals three intervals a period of high eqf 4000 2000 cal yr b p and two periods of low eqf 6500 4000 cal yr b p and 2000 cal yr b p to present which have been affected by the east asian monsoon due to insolation change and the cold air activity in high latitudes correlated with polar high pressure systems this long term variation is superimposed by millennial and centennial scale fluctuations with periodicities of 1137 739 214 162 137 127 and 111 yr implying drier conditions in the source areas in china the detrended eqf record correlates visually and statistically cross spectral analysis with the atmospheric d 14 c record solar proxy the centennial scale variability in eqf may be affected

palaeoenvironmental reconstruction of kathu pan south africa based on sedimentological data abstract several studies have highlighted the importance of collecting well dated records of palaeoenvironmental changes on desert margins particularly in the semi arid interior of southern africa here we describe sediments at three sites in kathu pan a pan complex overlying karstic bedrock at the southern edge of the kalahari basin sinkholes have exposed sedimentary sequences dating back to the pleistocene making it possible to document multiple palaeoenvironmental regimes in this landscape using a multi analytical sedimentological approach including micromorphology energy dispersive x ray spectrometry electron microprobe loss on ignition laser diffractometry and luminescence dating we demonstrate that the sediments at kathu pan represent an environment fluctuating among a number of thresholds for accumulation of different kinds of transported and authigenic sediments within the pleistocene sands at the base of our studied sedimentary sequence the presence of palygorskite indicative of less extreme evaporative control represents a semi arid environment from 156 11 ka to 32 2 ka marine isotope stages 6 3 increased moisture availability at 84 4 ka and at 96 5 ka possibly during marine isotope stages 5a and 5c respectively is reflected in the sands by the formation of palygorskite in concert with the deposition and oxidation of organic material as the climate became increasingly arid possibly in response to global cooling during the last glacial maximum 21 2 ka kathu pan crossed a threshold and deposition of caco3 dominated over that of palygorskite in the holocene beds within our studied unit alternating caco3 and organic dominated deposits sometimes in very fine laminae reflect an increase in the amplitude of either seasonal or annual changes in water availability

enso like modulated tropical pacific climate changes since 2 36 myr and its implication for the middle pleistocene transition el nino southern oscillation enso activity and the pacific walker circulation are controlled by the zonal sea surface temperature sst gradient between the western and eastern equatorial pacific eep and the corresponding barometric difference variations in the zonal sst gradient since the early pleistocene have primarily been triggered by changes in the sst in the eastern equatorial pacific however the response of the enso like long term state to the cooling of the eep and its coupling role with tropical pacific climate changes are still not well established here we present a high resolution grain size record spanning the last 2 36 myr obtained from marine core sediment located in the west philippine sea in order to decipher the tropical pacific climate changes and reveal its controlling mechanism by combining our data with other long term climatic records from the equatorial pacific we demonstrate that the cooling of sst and enhanced upwelling in the eep resulted in the development of the walker circulation and increased monsoon precipitation in luzon from 2 2 to 1 6 myr from 1 2 to 0 8 myr and since 0 2 myr ago the progressive cooling of the high latitudes in the quaternary may be responsible for our observation here a newly identified 100 kyr dominant period between 2 2 and 1 6 myr in the enso like modulated pacific climate records indicates that the enso like system may play a key role in facilitating or responding to the global climate changes

models for relative motion of crustal blocks within the carpathian region based on restorations of the outer carpathian thrust sheets details of the oligocene present day motion of the adriatic block with respect to europe can be determined by palinspastic restorations of the outer carpathians thrust sheets the arcuate nature of the carpathians poses problems for simple restorations of sections because they create converging restoration paths which require large amounts of strike parallel extension 40 50 such large amounts of extension are not seen on maps or in the field a combination of thrust transport directions changing with time between and within thrust sheets and divergent transport directions helps minimise the arc parallel extension necessary 18 25 the pannonian basin can be treated either as an area dominated by strike slip motion rigid block movements or as an area of back arc extension the differences in restoration geometry produced by these two scenarios help to indicate which of the two mechanisms was dominant the consequences of the rigid block restoration indicate the model is inappropriate because it requires approximately 20 clockwise rotation of the adriatic block during the late tertiary it also indicates at least 300 km strike slip motion distributed among the late tertiary faults of the dinaride balkanide and hellenide mountain belts the back arc extension model alleviates the the 20 clockwise rotation of the adriatic block and requires about 200 km distributed strike slip motion in yugoslavia and bulgaria

grain size distribution function of polymodal sediments in hydraulic and aeolian environments and numerical partitioning of the sedimentary components most continental sediments are polymodal composed of overlapping components of which the grain size generally obeys some type of natural distribution the grain size components and their function types can be determined from frequency and cumulative curve plots in order to define the function formula of the grain size distribution the function parameters can be estimated by fitting a defined function formula to the measured grain size data of the sample which simultaneously achieves numerical partitioning of the sedimentary components genetic analysis of grain size components of hydraulic and aeolian sediments demonstrates the following environmental implications fluvial sediment is composed of isolated saltation and suspension components the sediments in closed lake basins are dominated by a suspension silt clay component with a small proportion of saltation sand the fine sand component makes up the majority of desert sand overlapping with a small proportion of fine dust aeolian loess is composed of two overlapping components a short suspension time silt component and a long suspension time fine component aeolian material in the north pacific deep sea sediments is dominated by long suspension time fine dust the fine component in aeolian sediments shows a consistent grain size distribution and genetic connection from the desert sand loess of northern china to the north pacific ocean which is mainly transported by westerly winds and is dispersed in the atmosphere forming a background dust c 2002 elsevier science b v all rights reserved

correlation between climate events in the north atlantic and china during the last glaciation episodes of massive iceberg release heinrich events 1 3 into the north atlantic ocean during the last glaciation were associated with recurring episodes of unusually cold north atlantic surface water bond cycles 4 and cold air temperatures over greenland dansgaard oeschger events 5 6 four of the youngest of these cold events have also been reported in climate records from sites outside the north atlantic region7 but until now the entire suite has been identified only in north atlantic marine sediments greenland ice core records and tentatively in french lake sediments8 here we examine grain size data from chinese loess and intercalated accretionary palaeosols of last glacial age for evidence of similar climate signals remote from the north atlantic region we see grain size maxima with ages that match those of the last six heinrich events which we interpret as an indication of the changing strength of the east asian winter monsoon which largely controls the transport and deposition of central asian aeolian dust thus it seems that these heinrich events have left their signature in the chinese loess record this is consistent with simulations of the glacial climate9 which imply that the climates of the north atlantic and china were linked by the effect of westerly winds