recurrent holocene landslides a case study of the krynica landslide in the polish carpathians situated in the southern part of the polish outer carpathians the development of the krynica lanslide is presented in detail head scarps slide shoulders and colluvial ridges connected with particular episodes of sliding occur on the western slope of the parkowa gora mountain peaty silts and calcareous tufa suitable for the radiocarbon dating fill depressions within colluvial masses calcareous deposits contain rich assemblages of molluscs characterizing changes of the climate and the environment during the late vistulian and the holocene four stages in the evolution of the landslide correspond with phases of increased mass movements distinguished elsewhere in the carpathians according to radiocarbon dating as well as palynological and malacological analyses the phases of enhanced mass movement correlate in turn with climatic changes

lateglacial early holocene fluvial reactions of the jeetzel river elbe valley northern germany to abrupt climatic and environmental changes abstract mechanisms of climatic control on river system development are still only partially known palaeohydrological investigations from river valleys often lack a precise chronological control of climatic processes and fluvial dynamics which is why their specific forces remain unclear in this multidisciplinary case study from the middle elbe river valley northern germany multiple dating of sites palynostratigraphy radiocarbon and osl dating and high resolution analyses of environmental and climatological proxies pollen plant macro remains and ostracods reveal a continuous record of the environmental and fluvial history from the lateglacial to the early holocene biostratigraphical correlation to northwest european key sites shows that river system development was partially out of phase with the main climatic shifts the transition from a braided to an incised channel system predated the main phase of lateglacial warming 14 6 ka bp and the meandering river did not change its drainage pattern during the cooling of the younger dryas period environmental reconstructions suggest that river dynamics were largely affected by vegetation cover as a vegetation cover consisting of herbs dwarf shrubs and a few larger shrubs seems to have developed before the onset of the main lateglacial warming and pine forests appear to have persisted in the river valley during the younger dryas in addition two phases of high fluvial activity and new channel incision during the middle part of the younger dryas and during the boreal were correlated with changes from dry towards wet climatic conditions as indicated by evident lake level rises lateglacial human occupation in the river valley which is shown by numerous palaeolithic sites forming one of the largest settlement areas of that period known in the european plain is assigned to the specific fluvial and environmental conditions of the early allerod

origin of dolomites in the cretaceous maha sarakham evaporites of the khorat plateau northeast thailand abstract the khorat plateau of northeast thailand and laos was an area of widespread deposition of evaporites and siliciclastics maha sarakham formation during the cretaceous and three types of dolomites are associated with this formation 1 limpid dolomite 2 coarse subhedral and euhedral dolomite and 3 saddle dolomite limpid dolomite is present as isolated crystals in recrystallized clear halite beds while the other two types are only present as authigenic clusters and individual large crystals within the widespread basal anhydrite unit bau 1 1 m which defines the lowest member of the formation the 18 o pdb isotopic values and the 87 sr 86 sr ratios of the limpid dolomite are within the range of cretaceous seawater petrography and carbon and oxygen isotopes suggest that limpid dolomite was formed under shallow burial during times of freshening in a mostly marine fed aggrading halite salina dolomite formation was possibly influenced by bacterial metabolism the coarse crystalline and saddle dolomite types float within a matrix of coarse recrystallized anhydrite in the basal anhydrite the 18 o isotopic values of the coarse subhedral and euhedral dolomite types are more negative than the limpid dolomite and the 87 sr 86 sr ratios are more radiogenic than typical marine dolomite of the cretaceous saddle dolomite has even more negative 18 o isotopic values than the coarse euhedral dolomite the 87 sr 86 sr ratios of the saddle dolomite are also radiogenic the isotopic and petrographic data indicate that the dolomites in the basal anhydrite unit are late and authigenic but do not appear to replace a precursor carbonate rather they appear to have precipitated within the deep burial environment along a 1 2 m thick subsurface mixing interface between warm upwelling basinal brines and dense highly saline brines created by dissolving the underside of the overlying impervious halite bed the upwelling basinal waters presumably rose through the underlying siliciclastics of the khorat group and then moved laterally along the base of the maha sarakham salt the result of this inferred hydrologic process apparently is an accumulation of burial dolomite and recrystallized residual anhydrite in a petrographically complex unit that ultimately appear to be a solution residue the basal anhydrite unit

the impact of wallachian settlement on relief and alluvia composition in small valleys of the carpathian mts czech republic abstract the impact of the wallachian settlement on small mountain catchments has been studied at the example of skor ansk and hartisov streams moravskoslezske beskydy mts western outer carpathians between the 16th and the 19th centuries the wallachian people introduced pastoral management originating from the woodless balkans to the forested mid altitude mountain area under study this area was subjected to rapid settlement intense grazing in forests and slash and burn deforestation to assess the geomorphic effects of wallachian activity in the catchments studied grain size structure organic matter content and the plant macrofossil composition of the alluvia forming terrace levels in the mouths of the skor ansk and hartisov streams were analysed radiocarbon dating 137 cs and 210 pb analyses and dendrochronological dating were also applied to determine the age of the alluvia studied the results were compared with land use and land cover changes recorded on archival maps and pictures and with population changes in the study area it was found that the two successive trends of catchment settlement and later depopulation have led to the development of inset terraces on the outlet fans of the skor ansk and hartisov streams in the study catchments both settlement deforestation and depopulation land abandonment occurred very rapidly which also caused abrupt geomorphic changes before human disturbance fluvial erosion and the redeposition of older pleistocene deposits predominated as a result coarse gravel alluvia were deposited within stream channels the stage of massive overbank accumulation of fine grained alluvia was a reflection of intensified delivery of slope material into valley floors from catchments deforested by the wallachians the later stage of vertical incision of channels resulted from the decrease of sediment supply from hillslopes to river channels during catchment depopulation and afforestation

holocene development of the river lippe valley germany a case study of anthropogenic influence the characteristics of the holocene valley floor of the river lippe germany are atypical for a river in central europe the valley floor consists of three terrace levels which are not always clearly separated from each other analysis of the sediments making up the terraces indicates that they accumulated during the course of the entire holocene although there is insufficient information available to allow detailed determination of phases of fluvial change and stability responsible for terrace formation two of the terraces exist only in the lower reaches of the valley where they converge and diverge with the third the lowest terrace consists only of a narrow strip running parallel to the river channel the configuration of the valley floor may be explained by a series of anthropogenic influences the earliest human impact probably occurred about 2000 years ago when during their campaign against german tribes the romans built a towpath and may have changed the channel planform from its natural anabranching pattern to a meandering form by building small dams on local distributary forks implementation of artificial meander cut offs to improve navigation on the river began in medieval times the morphological response to these human interventions was primarily degradational in the 19th century artificial lateral fill was used to narrow the channel and the towpath was renewed several times the trace of the most recent towpath is still discernible as a narrow strip parallel to the river channel and it constitutes the lowest terrace level comparison between the bankfull discharge of a 4000 year old abandoned channel and the formative flow for the modern channel supports the premise that prior to anthropomorphic influence the natural planform was anabranched copyright 2000 john wiley sons ltd

trends and controls of holocene floodplain sedimentation in the rhine catchment article i nfo holocene floodplain sedimentation in the rhine catchment is controlled by human and climate impacts intricate river behaviour modifies the fluvial response to the external impacts making cause effect analysis difficult especially on large spatial scales to better understand the relative importance and interdependencies of external and internal controls temporally resolved floodplain sedimentation rates are established using three different methods i floodplain storage studies on the trunk stream ii depth age analysis of overbank deposits from different parts of the catchment and iii cumulative frequency distributions of 14 c ages from floodplain deposits from various parts of the catchment the applied methodology strongly differs with the available temporal resolution and the size of the corresponding catchment all three methods show a strong increase in sedimentation rate for more recent periods that can be linked to increasing human impact evidences for climate impacts and intricate river behaviour are less clear and hindered by insufficient temporal resolution of the currently available data

trends and evolution of contamination in a well dated water reservoir sedimentary archive the brno dam moravia czech republic the sedimentary record from dams can provide important information about stratigraphy and pollution history of densely populated river basins the brno dam is a small reservoir within the morava river catchment czech republic accumulating lacustrine sediments since 1940 dam filling the stratigraphy of the dam sediments was studied using multiproxy stratigraphic analysis x ray densitometry bulk magnetic susceptibility diffuse spectral reflectance and cation exchange capacity of five sediment cores supported by ground penetration radar sections concentrations of heavy metals were studied by x ray fluorescence analysis the thickness of the dam sediments decreases from 220 cm in the proximal part near the feeder to only 10 cm in the distal part near the dyke sediments consist predominantly of finely laminated silty sands silts and clays the sedimentation rate for the last 22 years inferred from 137cs dating decreases from 4 2 cm per year in the proximal part of the dam to 0 29 cm per year in its distal part distinct long term trends were found in the depth profiles of heavy metal concentrations the heavy metal contents increase significantly after 1940 in all cores with peak concentrations confined to layers deposited in the 1960s and 1980s a decreasing trend occurred after 1989 the decline in czech heavy industry the results also show that heavy metal contamination is dependent on lithology hyperpycnal flow layers related to floods increased concentrations of phosphorus in the sediments indicate long term eutrophication of the dam despite the recent decreasing trends in heavy metal concentrations the phosphorus contents remain high in recent years and have caused persisting problems with algal growth in the dam mentioned by previous authors

environmental changes during the holocene climatic optimum in central europe human impact and natural causes abstract the priority programme changes of the geo biosphere aimed to reconstruct the environmental history of central europe with emphasis on the time interval from 9000 to 5500 cal bp time slice ii coinciding with the holocene climatic optimum during this period the onset of human activities such as settlement agriculture and animal husbandry caused environmental changes studies of different landscape units in germany were carried out to identify these anthropogenically induced changes and to distinguish them from natural effects on the environmental system the investigated archives included laminated lake sediments fluvial sediments colluvia and soils speleothems peat and coastal sediments the different archives were examined using refined research methods including a variety of sedimentary and geochemical analyses together with pollen analysis and dating methods for the establishment of a reliable chronology the results of the various research groups are summarised and critically discussed based on these results the climatic optimum can be subdivided into three periods 1 the early atlantic from 9000 to 7500 cal bp with negligible human impact and stable environmental conditions 2 the late atlantic during early and middle neolithic from 7500 to 6300 cal bp with pollen evidence for vegetation changes but only negligible changes detectable in other proxy records and 3 the late atlantic during the younger neolithic jungneolithikum after 6300 cal bp with human impact observed in many archives and proxy records especially in the pollen record but also in lacustrine and fluvial sediments during the whole climatic optimum natural causes such as minor shifts of temperature did not induce substantial environmental changes though some changes such as temporary droughts may have facilitated and amplified the observed human impact

the major ion composition of permian seawater abstract the major ion mg2 ca2 na k so42 and cl composition of permian seawater was determined from chemical analyses of fluid inclusions in marine halites new data from the upper permian san andres formation of texas 274 272 ma and salado formation of new mexico 251 ma analyzed by the environmental scanning electron microscopy esem x ray energy dispersive spectrometry eds method along with published chemical compositions of fluid inclusions in permian marine halites from north america two formations of different ages and the central and eastern european basins eight formations of four different ages show that permian seawater shares chemical characteristics with modern seawater including so42 ca2 at the point of gypsum precipitation evolution into mg2 na k so42 cl brines and mg2 k ratios 5 permian seawater however is slightly depleted in so42 and enriched in ca2 although modeling results do not rule out ca2 concentrations close to those in present day seawater na and mg2 in permian seawater are close to slightly below their concentrations in modern seawater permian and modern seawater are both classified as aragonite seas with mg2 ca2 ratios 2 conditions favorable for precipitation of aragonite and magnesian calcite as ooids and cements the chemistry of permian seawater was modeled using the chemical composition of brine inclusions for three periods lower permian asselian sakmarian 296 283 ma lower permian artinskian kungurian 283 274 ma and upper permian tatarian 258 251 ma parallel changes in the chemistry of brine inclusions from equivalent age evaporites in north america central europe and eastern europe show that seawater underwent secular variations in chemistry over the 50 million years of the permian modeled so42 concentrations are 20 mmol per kg h2o mmolal and 19 mmolal in the asselian sakmarian and artinskian kungurian with higher concentrations in the upper permian tatarian 23 mmolal modeled ca2 is at or above its concentration in modern seawater throughout the permian mg2 is close to slightly below its concentration in modern seawater 55 mmolal in the asselian sakmarian 52 mmolal and tatarian 52 mmolal but slightly higher than modern seawater in the artinskian kungurian 60 mmolal mg2 ca2 ratios are 3 5 total range 2 7 to 5 5 in the lower permian and rose slightly to 3 7 total range 3 1 to 5 8 in the upper permian primarily due to decreases in ca2 these results are consistent with models that predict oscillations in the major ion composition of phanerozoic seawater on the basis of changes in the midocean ridge river water flux ratio driven by changes in the rate of midocean ridge crust production the permian was characterized by low sea levels icehouse conditions and southern hemisphere glaciation such conditions analogous to the present ice age and the similarities between permian seawater and modern seawater all suggest that general phanerozoic supercycles driven by mantle convection and global volcanicity also control the major ion chemistry of seawater

holocene climate variability as reflected by mid european lake level fluctuations and its probable impact on prehistoric human settlements abstract a data set of 180 radiocarbon tree ring and archaeological dates obtained from sediment sequences of 26 lakes in the jura mountains the northern french pre alps and the swiss plateau was used to construct a holocene mid european lake level record the dates do not indicate a random distribution over the holocene but form clusters suggesting an alternation of lower and higher climatically driven lake level phases they provide evidence of a rather unstable holocene climate punctuated by 15 phases of higher lake level 11 250 11 050 10 300 10 000 9550 9150 8300 8050 7550 7250 6350 5900 5650 5200 4850 4800 4150 3950 3500 3100 2750 2350 1800 1700 1300 1100 750 650 cal bp and after 1394 ad a comparison of this mid european lake level record with the gisp2 polar circulation index pci record the north atlantic ice rafting debris ird events and the 14 c record suggests teleconnections in a complex cryosphere ocean atmosphere system correlations between the gisp2 pci the mid european lake level the north atlantic ird and the residual 14 c records suggest that changes in the solar activity played a major role in holocene climate oscillations over the north atlantic area

diagenetic origin of basal anhydrite in the cretaceous maha sarakham salt khorat plateau ne thailand development of a diagenetic anhydrite bed at the base of the cretaceous maha sarakham saline formation the basal anhydrite member of the khorat plateau in north eastern thailand took place due to leaching and or pressure dissolution of salt at the contact between an underlying active sandstone aquifer system and an overlying massive halite dominated evaporite sequence basal evaporites composed of halite with intercalated anhydrite of the latter sequence are undergoing dissolution as a result of subsurface flushing with anhydrite produced as the insoluble residue the result is a 1ae1 m thick interval of nodular anhydrite displaying unique basin wide continuity observed textures petrographic features and chemical data from the anhydrite and associated authigenic minerals support the origin of the basal anhydrite member as an accumulation residue from the dissolution of the maha sarakham salts petrographically the anhydrite in this unit is made up of crystals that are blocky and recrystallized sheared generally elongated and broken and is bounded at the bottom by organic rich stylolite surfaces authigenic and euhedral dolomite and calcite crystals are associated with the anhydrite traces of pyrite galena and chalcopyrite are present along the stylolite surfaces suggesting supply of fresh water from the underlying sandstone at highly reducing conditions of burial the d 34 s of sulphate in the basal anhydrite averages 15 cdt and falls within the isotopic composition of the anhydrite in the cretaceous maha sarakham formation proper and the cretaceous values of marine evaporites measured d 18 o in dolomite range from 4ae37 to 14ae26 pdb suggesting a re equilibration of dolomite with basinal water depleted in 18 o and possible recrystallization of dolomite under relatively elevated temperatures the d 13 c however varies from 1ae57 to 2ae53 pdb suggesting a contribution of carbon from oxidation of organic matter this basal anhydrite bed similar to basinwide beds found at the bottom of many giant evaporite sequences has always been considered to be depositional here at the base of the maha sarakham formation we demonstrate that the anhydrite is diagenetic in origin and was formed by accumulation of original anhydrite by dissolution of interbedded halite from waters circulating though the underlying aquifer it represents an upsidedown caprock

late holocene history of the moldova river valley romania abstract this paper describes the results of geomorphological sedimentological and 14 c analyses of late holocene fluvial sequences in the moldova river valley of romania this river originates from the carpathians mountains and is known for the extent of its large floodplain and sediment thickness between the molid and timisesti localities river length 86 km numerous large fossil trunks of oak poplar and beech trees are exposed in the riverbanks six wood samples were selected for radiocarbon absolute dating conventional method and their ages ranged from 410 to 3200 cal yrs bp the thickness of the alluvial sediments above the sampled fossil trunks varied between 2 and 3 m and these sediments predominantly consisted of coarse gravel materials that had similar granulometry to sediments that were present in the modern riverbed additionally in the same investigated areas successive floodplain cross sections were constructed based on more than 20 hydrogeological boreholes for each cross section all data were used to calculate the local values of bed loads and these values were compared to the absolute ages of the fossil trunks and were in the range of 300 m 3 m and 5500 m 3 m based on the calculated values during the last 780 years the floodplain sedimentation rates were estimated to be in the range of 0 4 m 3 year at the molid section which was located in the mountainous area of the valley and 44 km downstream from the river headwater and during the last 410 years the sedimentation rate at the praxia section which was located 125 km downstream from the river headwater was 13 3 m 3 year in the past 100 years the fluvial processes along the moldova river were dominated by a narrowing by an average of 76 and an incision up to 2 5 m and a channel metamorphosis from braided to wandering was reported these results are discussed in the context of late holocene regional and local palaeoclimatic reconstructions as well as that of human interventions

forced stage response to a moving hurricane abstract the upper ocean s response to three hurricanes norbert 1984 josephine 1984 and gloria 1985 is examined using field observations and a numerical ocean model our goal is to describe the physical processes that determine the structure and amplitude of hurricane driven upper ocean currents all three of these northern hemisphere hurricanes produced a rightward biased response of the mixed layer current and transport this asymmetry arises because the wind stress vector rotates clockwise on the right side of the track and remains nearly parallel with the inertially rotating mixed layer current during most of the hurricane passage the maximum observed mixed layer current varied from 0 8 m s 1 in response to josephine which was a large but comparatively weak hurricane to 1 7 m s 1 in response to gloria which was very large and also intense these cases have been simulated with a three dimensional numerical model that includes a treatment of wind driven vertical mixing within the primitive

glauberite halite association of the zaragoza gypsum formation lower miocene ebro basin ne spain glauberite is the most common mineral in the ancient sodium sulphate deposits in the mediterranean region although its origin primary or diagenetic continues to be a matter of debate a number of glauberite deposits of oligocene miocene age in spain display facies characteristics of sedimentologic significance in particular those in which a glauberite halite association is predominant in this context a log study of four boreholes in the zaragoza gypsum formation lower miocene ebro basin ne spain was carried out two glauberite halite lithofacies associations a and b are distinguished association a is composed of bedded cloudy halite and minor amounts of massive and clastic glauberite association b is made up of laminated to thin bedded clear macrocrystalline massive clastic and contorted lithofacies of glauberite and small amounts of bedded cloudy halite transparent glauberite cemented by clear halite as well as normal graded and reverse graded glauberite textures are common this type of transparent glauberite is interpreted as a primary subaqueous precipitate gypsum thenardite or mirabilite are absent in the two associations the depositional environment is interpreted as a shallow perennial saline lake system in which chloride brines association a and sulphate chloride brines association b are developed the geochemical study of halite crystals bromine contents and fluid inclusion compositions demonstrates that conditions for co precipitation of halite and glauberite or for precipitation of na sulphates mirabilite thenardite were never fulfilled in the saline lake system

sedimentology of the cretaceous maha sarakham evaporites in the khorat plateau of northeastern thailand abstract evaporites of the cretaceous to early tertiary maha sarakham formation on the khorat plateau of southeast asia thailand and laos are composed of three depositional members that each include evaporitic successions each overlain by non marine clastic red beds and are present in both the khorat and the sakon nakhon sub basins these two basins are presently separated by the northwest trending phu phan anticline the thickness of the formation averages 250 m but is up to 1 1 km thick in some areas in both basins it thickens towards the basin centre suggesting differential basin subsidence preceding or during sedimentation the stratigraphy lithological character and mineralogy of the evaporites and clastics are identical in both basins suggesting that they were probably connected during deposition evaporites include thick successions of halite anhydrite and a considerable accumulation of potassic minerals sylvite and carnallite but contain some tachyhydrite and minor amounts of borates during the deposition of halite the basin was subjected to repeated inflow of fresher marine water that resulted in the formation of anhydrite marker beds sedimentary facies and textures of both halite and anhydrite suggest deposition in a shallow saline pan environment many halite beds however contain a curious sieve like fabric marked by skeletal anhydrite outlines of gypsum precursor crystals and are the product of early diagenetic replacement by halite of primary shallow water gypsum the 34s isotopic values obtained from different types of anhydrite interbedded with halite range from 14 3 to 17 0 cdt suggesting a marine origin for this sulphate bromine concentration in the halite of the lower member begins around 70 ppm and systematically increases upward to 400 ppm below the potash rich zone also suggesting evaporation of largely marine waters in the middle member the initial concentration of bromine in halite is 200 ppm rising to 450 ppm in the upper part of this member the bromine concentration in the upper member exhibits uniform upward increase and ranges from 200 to 300 ppm the presence of tachyhydrite in association with the potassic salts was probably the result of 1 the large volumes of halite replacement of gypsum on a bed by bed basis releasing calcium back into the restricted waters of the basin and 2 early hydrothermal input of calcium chloride rich waters the borates associated with potash rich beds likely resulted from erosion and influx of water from surrounding granitic terrains however hydrothermal influx is also possible interbedded with the evaporites are non marine red beds that are also evaporative with displacive anhydrite nodules and beds and considerable amounts of displacive halite the 34s isotopic values of this anhydrite have non marine values ranging from 6 4 to 10 9 cdt these data indicate that the khorat and sakhon nakhon basins underwent periods of marine influx due to relative world sea level rise but were sporadically isolated from the world ocean

oscillations of the water balance during the holocene in interior central europe features dating and consequences abstract the continental water balance depends on precipitation and evaporation with the latter due to temperature moreover both the components of weather and climate are influenced by the annual seasonality all these factors have changed during the last millennia and periods of significant moisture have alternated with ones of low moisture evidence of these oscillations results from geostratigraphical subdivision of sequences of freshwater lime deposits and from lake level changes of inland lakes but also from many archaeological observations concerning settlement distribution all these observations reflect oscillations that can be correlated through archaeological and other dating alternation of drier and moister periods in the course of the central european holocene can be recognized

upper ocean thermal structure and the western north pacific category 5 typhoons part i ocean features and the category 5 typhoons intensification abstract category 5 cyclones are the most intense and devastating cyclones on earth with increasing observations of category 5 cyclones such as hurricane katrina 2005 rita 2005 mitch 1998 and supertyphoon maemi 2003 found to intensify on warm ocean features i e regions of positive sea surface height anomalies detected by satellite altimeters there is great interest in investigating the role ocean features play in the intensification of category 5 cyclones based on 13 yr of satellite altimetry data in situ and climatological upper ocean thermal structure data best track typhoon data of the u s joint typhoon warning center together with an ocean mixed layer model 30 western north pacific category 5 typhoons that occurred during the typhoon season from 1993 to 2005 are systematically examined in this study two different types of situations are found the first type is the situation found in the western north pacific south eddy zone sez 21 26 n 127 170 e and the kuroshio 21 30

tripartite climate reversal in central europe 5600 5300 years ago abstract the history of variations in water level of lake constance as reconstructed from sediment and pollen analysis of a sediment sequence from the archaeological site of arbon bleiche 3 shows an abrupt rise in lake level dendrochronologically dated to 5375 yr ago 5320 yr relative to ad 1950 this event paralleled by the destruction of the neolithic village by fire provoked the abandonment of this prehistoric lake shore location established in the former shallow bay of arbon bleiche and was the last of a series of three episodes of successively higher lake level the first occurring at 5600 5500 cal yr b p the dendrochronologically dated rise event was synchronous with an abrupt increase in atmospheric 14 c this supports the hypothesis of an abrupt climate change forced by varying solar activity moreover the three successive episodes of higher lake level between 5600 and 5300 cal yr b p at arbon bleiche 3 coincided with climatic cooling and or changes in moisture conditions in various regions of both hemispheres this period corresponds to the mid holocene climate transition onset of the neoglaciation and suggests inter hemispheric linkages for the climate variations recorded at arbon bleiche 3 this mid holocene climate reversal may have resulted from complex interactions between changes in orbital forcing ocean circulation and solar activity finally despite different seasonal hydrological regimes the similarities between lake level records from lake constance and from jurassian lakes over the mid holocene period point to time scale as a crucial factor in considering the possible impact of climate change on environments

flood events in transylvania during the medieval warm period and the little ice age we present here the first record of past flooding activity from the carpathian mountains eastern europe based on documentary evidence and sedimentary records along one of the main rivers draining

meganodular anhydritization a new mechanism of gypsum to anhydrite conversion palaeogene neogene ebro basin north east spain a number of palaeogene to early neogene gypsum units are located along the southern margins of the ebro basin north east spain these marginal units of eocene to lower miocene age formed and accumulated deposits of ca sulphates gypsum and anhydrite in small shallow saline lakes of low ionic concentration the lakes were fed mainly by ground water from deep regional aquifers whose recharge areas were located in the mountain chains bounding the basin and these aquifers recycled and delivered ca sulphate and na chloride from mesozoic evaporites triassic and lower jurassic in outcrop the marginal sulphate units are largely secondary gypsum after anhydrite and exhibit meganodules from 0 5 to 5 m across and large irregular masses in the sub surface these meganodules and masses are mostly made of anhydrite which replaced the original primary gypsum the isotopic composition 11 1 to 17 4 for 18ovsmow 10 7 to 15 3 for 34svcdt of secondary gypsum in this meganodular facies indicates that the precursor anhydrite derived from in situ replacement of an initial primary gypsum as a result of ascending circulation of deep regional fluid flows through the gypsum units near the basin margins the gypsum was partly altered to anhydrite within burial conditions from shallow to moderate depths from some metres to a few hundred metres at such depths the temperatures and solute contents of these regional flows exceeded those of the ground water today these palaeoflows became anhydritizing solutions and partly altered the subsiding gypsum units before they became totally transformed by deep burial anhydritization the characteristics of the meganodular anhydritization for example size and geometry of the meganodules and irregular masses spatial arrangement relations with the associated lithologies and the depositional cycles presence of an enterolithic vein complex and palaeogeographic distribution are compared with those of the anhydritization generated both in a sabkha setting or under deep burial conditions and a number of fundamental differences are highlighted

floodplain architecture of an actively meandering river the ploucnice river the czech republic as revealed by the distribution of pollution and electrical resistivity tomography abstract the aim of this study was to describe the floodplain architecture of the ploucnice river a naturally meandering river in the czech republic using manual drill coring the element analysis of sediments and electrical resistivity tomography ert the ploucnice river has received diffuse pollution since the early twentieth century mainly pb followed by a prominent temporally well defined pollution pulse from uranium mining in the 1970s and 1980s mainly u and 226ra the pollution created a chemostratigraphic temporal framework for overbank fines we used geographical information systems gis to describe the channel s dynamics and visualise fluvial landforms we sampled and analysed the finest floodplain sediments in the top 1 to 2 m of the floodplain fill silty and sandy deposits and we used ert to visualise bodies of coarser and deeper strata at depths down to 3 m several limits of ert imaging have been found by a comparison of the resistivity domains with lithological descriptions of the cores several decimetre thick strata were not revealed they are below the spatial resolution of that method and humidity affected the results that were obtained in the topmost strata the space for deposition of fluvial sediments in the ploucnice river is being created by 1 natural lateral shifts in the channel up to 0 5 m year 2 meander loop development and cutoffs at the timescale of decades to centuries and spatial scale of up to 1 4 of the floodplain width and 3 more substantial reorganisation of the channel structure by avulsions probably at the timescale of centuries these processes continuously create space for the deposition of overbank fines on the top of former point bars and in swales and abandoned channels as a consequence of the speed of the channel shifts at least 80 of the fine grained top of the floodplain fill overbank fines was reworked over approximately three centuries

initial stages and evolution of recently abandoned meanders revealed by multi proxy methods in the odra river czech republic abstract oxbow lakes represent important geomorphic and depositional units of meandering river systems whose rates of sediment accumulation may significantly exceed those of surrounding floodplains natural and artificial oxbow lakes may differ considerably although both can offer unique sedimentary records of recent past events in river catchments we provide an insight into the initial stages of oxbow lake evolution in terms of morphology dynamics sediment accumulation rates sediment architecture and switching between sediment source areas the study is based on a combination of geomorphic observations multi proxy stratigraphic analysis and geochemistry of sediment cores in four abandoned meanders of the odra river in the northeastern part of the czech republic two of the meanders were formed in non regulated parts of the floodplain following a flood in 2010 in addition two abandoned meanders formed by the artificial shortening of an upstream section of the odra river were studied in order to compare processes in both sections several site specific factors controlled the sedimentation patterns in the naturally abandoned meanders the initial stages of oxbow lake succession were characterised by extremely high sediment accumulation rates up to 32 cm yr which caused the stara b la abandoned meander to completely fill up over the course of several years relative to natural oxbow lakes artificial lake successions revealed much slower sedimentation rates and higher levels of organic sedimentation and eutrophic conditions the accumulation rates were influenced by both local oxbow lake size position and geometry and catchment wide factors sediment yield the annual occurrence of low magnitude floods was an important factor in the natural reaches of the odra river the geochemical composition of sediments in naturally and anthropogenically formed abandoned meanders also differed due to the fact that the river tributaries drain two geologically contrasting areas the variscan bohemian massif and the cretaceous cenozoic outer western carpathians respectively

late holocene evolution of the becva river floodplain outer western carpathians czech republic abstract to reconstruct the geomorphic imprint of the anthropogenic and natural environmental changes in the late holocene we studied the alluvial record of the becva river floodplain outer western carpathians czech republic coring geophysical sounding and lithological analysis of floodplain deposits supported by ams accelerator mass spectrometry dating enabled the establishment of the primary evolutionary stages of late holocene floodplain evolution during the late atlantic and early subboreal periods gravel aggradation and braided environments occurred in the studied floodplain the late subboreal and early subatlantic are characterised by overbank sedimentation and the middle subatlantic is marked by the recurrence of gravel aggradation a major incision phase took place during the mediaeval warm period the onset of overbank sedimentation in the 15th century correlated with ongoing deforestation of the lower parts of catchment and colonisation of the mountain ridges during the 16th 17th centuries further accelerated this process during the 20th century reforestation of mountains and river channel training resulted in a significant incision phase our data suggest that climate fluctuations were major driving factors for the morpho sedimentary evolution of the floodplain approximately up to the 12th century whereas in the latter evolution period anthropogenic activity superseded natural factors this transition occurred more than one millennium later than in other central and western european catchments

upper ocean thermal structure and the western north pacific category 5 typhoons part ii dependence on translation speed abstract using new in situ ocean subsurface observations from the argo floats best track typhoon data from the u s joint typhoon warning center an ocean mixed layer model and other supporting datasets this work systematically explores the interrelationships between translation speed the ocean s subsurface condition characterized by the depth of the 26 c isotherm d26 and upper ocean heat content uohc a cyclone s self induced ocean cooling negative feedback and air sea enthalpy fluxes for the intensification of the western north pacific category 5 typhoons based on a 10 yr analysis it is found that for intensification to category 5 in addition to the warm sea surface temperature generally around 29 c the required subsurface d26 and uohc depend greatly on a cyclone s translation speed it is observed that even over a relatively shallow subsurface warm layer of d26 60 70 m and uohc 65 70 kj cm 2 it is still possible to have a sufficient enthalpy flux to intensify the storm to category 5

palaeoflood record of the tagus river central spain during the late pleistocene and holocene abstract palaeoflood hydrology of the tagus river central spain was reconstructed from slackwater deposits and palaeostage indicators in two canyon reaches located at el puente del arzobispo in the central part of the catchment 35 000 km 2 in drainage area and in alcantara at the lower part of the catchment 52 000 km 2 in drainage area near the portuguese border the palaeoflood record with more than 80 flood events shows clusters of floods at specific periods from 9440 to 9210 14 c yr bp 8540 8110 bc 8500 to 8000 14 c yr bp 7500 7000 bc 6750 14 c yr bp 5000 bc 1200 to 950 14 c yr bp ad 785 1205 410 14 c yr bp ad 1450 1500 170 to 80 14 c yr bp ad 1670 1950 the largest flood s occurred during the periods 9440 to 9210 14 c yr bp 6750 14 c yr bp and 1200 to 950 14 c yr bp reaching minimum discharge estimates of between 4000 and 4100 m 3 s 1 in the el puente del arzobispo reach and 13 700 15 000 m 3 s 1 in the alcantara reach these periods with increased flood magnitude and or frequency in the tagus river are strongly related to increased moisture influx and winter precipitation in the iberian peninsula especially in the western zone proxy records sensitive to winter precipitation such as lake levels and vegetation changes indicated by pollen records are in good agreement with the clusters of floods found in the tagus river this flood variability seems to correspond to changes in the prevailing atmospheric circulation pattern affecting the iberian peninsula

facies and depositional environment of the holocene evaporites in the ras shukeir area gulf of suez egypt the holocene evaporite sequence in the ras shukeir area conformably overlies marine shell banks and cross bedded to graded bedded beach sands and gravels the evaporite sequence is represented by gypsum anhydrite layers that are interbedded with mudstone layers field and petrographic investigations of the evaporite deposits revealed two facies types laminated evaporite facies primary and nodular to enterolithic anhydrite facies diagenetic the laminated evaporite facies is subdivided from the bottom to top into regular laminated evaporite chevron gypsum algal micrite laminations and wavy algal laminated evaporite based on their textures and fabrics the regular and wavy laminated evaporite facies are interpreted as primary deposits in a coastal lagoon and salina environment the chevron gypsum algal micrite facies formed by the growth of chevron gypsum at the sediment water interface within a shallow subtidal lagoonal environment that was characterized by extensive benthic algal mats the nodular to enterolithic anhydrite facies is secondary and formed diagenetically within a siliciclastic supratidal sediment some of the laminated evaporite facies have been diagenetically altered in a supratidal sabkha environment as evidenced by the following 1 the partial formation of nodular evaporite instead of laminated evaporite 2 disruption of gypsum laminations by plant roots and rootlets as well as by precipitation of lenticular gypsum on the root wall and 3 partial dissolution of halite laminae and the formation of wavy anhydrite laminae consequently the holocene evaporites in the ras shukeir area were deposited in a shallow semi closed to closed basin that was separated from the gulf of suez trough changing sea level led to progradation of the evaporite facies from subtidal to intertidal lagoon and salina to a supratidal sabkha

sedimentary record of early wood burning in alluvium of mountain streams in the bieszczady range polish carpathians abstract the youngest alluvium in the headwater part of the san valley in the bieszczady range polish carpathians is sandy mud lying with a sharp contact on older gravels the mud alluvium contains at its base accumulations of wood debris rich in charcoal radiocarbon dates of the wood debris suggest that the mud alluvium was laid down during the second half of this last millennium the accumulation of the wood debris seems to be related to the fire clearance of forests by early farmers who settled in the area the higher part of the mud alluvium includes dispersed wood debris ash and charcoal whose appearance is related to the activity of small wood processing establishments until the early 20th century

late holocene evolution of a floodplain impounded by the smrduta landslide carpathian mountains czech republic we present here a detailed study of the sedimentary archive within a landslide controlled impounded floodplain smrduta site czech flysch carpathians using geochronological 14c and 137cs sedimentological and pollen evidence a sedimentary sequence deposited above the landslide dam points to three highly discontinuous and instantaneous depositional events dated to 4 6 and 2 0 cal ka bp whereas the last cycle started approximately in the 17 18th centuries and has continued to recent times stages of mass movement activity revealed by the smrduta landslide correlate well with major humid late holocene oscillations suggesting its high sensitivity to century scale climatic deteriorations the character of lithological units forming individual sedimentary pulses erosional hiatuses and sedimentary traces caused by the july 1997 extreme flood indicate a decisive role of large flood events during accretion and erosion of the floodplain impounded section

holocene reactivations of catastrophic complex flow like landslides in the flysch carpathians czech republic slovakia catastrophic complex flow like landslides cflls are characterised by a deep seated retrogressive landslide of structurally unfavourably oriented rocks and earthflows that occupy the lower slope positions and originate due to the liquefaction of material accumulated on the upper slopes these landslides are locally important geomorphic agents of late quaternary mountain evolution in the flysch belt of the outer western carpathians czech republic slovakia most of the cflls dammed and steepened adjacent valleys radiocarbon dating suggests that a majority of them moved repeatedly throughout the holocene namely approx every 1 2 ka dated events occurred during humid phases of the younger dryas holocene transition 11 5 9 4 cal ka bp atlantic chronozone 7 4 6 6 cal ka bp the beginning of the subboreal chronozone ca 4 6 cal ka bp and primarily within the subatlantic chronozone at ca 2 0 8 cal ka bp 50 of all events our study suggests that slopes based on an unfavourable structural setting and affected by long term deep seated gravitational deformations may produce cflls even if they are located in medium high mountains although our chronological dataset is influenced by the erosion of older landforms most of the dated reactivations correlate with regional increase in precipitation identified by previous palaeoenvironmetal studies

spatio temporal evolution of the choisille river southern parisian basin france during the weichselian and the holocene as a record of climate trend and human activity in north western europe abstract the morpho sedimentary evolution of the choisille floodplain lowland river catchment 288 km2 a tributary of the river loire in the south western parisian basin was studied through 61 core drillings along eight transects and a geophysical survey located in four stretches of the river stretches a and b correspond to two sub catchments and stretches c and d are in the main valley sixty 14c and four osl datings were obtained and sediments were analysed on seven reference cores eight phases of evolution differing markedly from the evolution of more northern areas in the parisian basin and north western europe were identified from spatio temporal distribution of nine lithological facies the deepest incision phase 1 occurred during the first part of the weichselian followed by the deposition of a gravelly sandy unit phase 2 during the middle pleniglacial which was deeply incised phase 3 probably during the bolling from the allerod up to the last third of the boreal phase 4 sedimentation was continuously dominated by peaty deposits with no evidence of either increased hydraulic energy during the younger dryas or of incision during the lateglacial holocene transition this trend seems to reflect the specificity of the south western parisian basin climate from the late weichselian up to the end of the boreal due to the influence of the atlantic ocean compared to more northern areas where the climate was more continental the downstream incision trend during the last third of the boreal up to the subatlantic phases 5 and 6 indicates a sharp increase in precipitation and vegetation cover the lack of peaty sediments widespread in north western europe and also of precipitated carbonates frequent in the parisian basin seems to be due to local physiographic characteristics the main part of the sediment filling which is principally silty and retrograde began during the subatlantic phase 7 and 8 as a result of deforestation of the plateaux for crop farming high human induced sediment yield and storage concealed the possible impacts of climate change on fluvial dynamics lithological facies change from phase 7 to 8 can only indicate the autogenic morphological evolution of the floodplain in accretion the non univocal upstream downstream variation in the start of phase 7 shows that sediment yield varied in space and time in the catchment particularly in relation to the agricultural potential of the different areas this observation could be used to testify human induced sedimentation in other catchments

morava river floodplain development during the last millennium stražnicke pomoravi czech republic floodplain sediments deposited along the lower course of the morava river eastern czech 206 pb 207 pb and pop ddt pcb analysis and 137 cs activity data thecu trienmethodwasusedforstratigraphicallycorrelatingthesedepositsbasedonthevariationofexpand able clay minerals in the sediments the resulting stratigraphic pattern reveals the alluvial history of the cur rently active river channel system since the end of the first millennium ad fine overbank clayey sediments deposited during the mediaeval warm period were eroded from cultivated fields newly formed during mediaeval colonization between 1250 and 1450 these fine deposits are overlain by coarser floodplain sedi mentsofthe littleiceage indicatingachangeinthesedimentsourcesincethesixteenthcentury ad anda substantial increase in the sediment load in the second half of twentieth century the straunicke pomoravi floodplaindepositsrepresentavaluablepalaeoenvironmentalarchiveofthelastmillennium containingrecords offluvialprocessesconsiderablyalteredbyhumanactivities

sensitivity of west and central european river systems to environmental changes during the holocene a review abstract sediment deposition in floodplains is an essential part of the sediment dynamics of a catchment these sediment dynamics can vary largely on a holocene time scale under the influence of driving forces such as land use and climatic variations in this paper we review the holocene floodplain sediment deposition history of rivers in west and central europe with special attention to the influence of climate and land use variability during the early holocene preboreal to atlantic period most floodplains were rather stable with limited floodplain aggradation after this initial phase of relative stability sedimentation rates increase during the middle and late holocene with often the most important deposition phase during the last 1000 to 2000 a the start of the increase in sedimentation varies spatially with an earlier start in the west france germany then in the east poland belarus ukraine while there are also local differences between regions which are settled early e g loess regions compared to later settled regions the sedimentation history of most floodplains can be linked to the local land use history while influence of climatic variations on floodplain aggradation is often reported to be of minor importance processes related to bedload are often reported to be more influenced by climatic events relationships between the driving forces and the sediment history are mainly based on synchronicity and there is seldom proof for a direct causal relationship future research should focus on a system based approach integrating the floodplain deposition in the entire sediment dynamics which includes also erosion colluvial deposition and export main research questions that need further attention include integration of system based concepts like landscape connectivity and buffering effects and also the assessment of the individual contribution of land use changes and climatologic variations on the sediment dynamics detailed sediment budget studies combined with modeling studies can make an important contribution to the understanding of floodplain sediment dynamics

grain size of the overbank deposits as carriers of paleogeographical information abstract overbank deposits of the vistula river and its tributaries were deposited during the whole late glacial and the holocene but at various rates they are differentiated with respect to the grain composition that corresponds to climatic vegetation changes at the turn of the late glacial and the holocene to anthropogenic deforestation in the neoholocene and to the distance from an active channel

quantification and regulation of organic and mineral sedimentation in a late holocene floodplain as a result of climatic and human impacts taligny marsh parisian basin france quantification in grams per metres squared per year of the sediment accumulation in a flood plain marsh located in the southwestern parisian basin showed that there is no close relationship between the accumulation of organic matter om and mineral matter mm during the late holocene and provided an accurate view of the distinct yield and storage conditions of both sediment components endogenic om accumulation in peaty sediments is not related to the climate but to felling of the alder forest and its substitution by cyperaceae and paludal taxa in the marsh iron age and middle ages mm accumulation expresses mainly the sediment yield on the slopes determined by landuse during an initial phase from the late neolithic to the early middle ages land use change from crop cultivation to pastureland possibly related to climate deterioration led to a decrease in the sediment yield during a second phase since the early middle ages the considerable development of crop cultivation over pasturing even during periods of climate deterioration such as the little ice age led to a sharp increase in sediment yield however although sediment yield was high the hydrodynamics in the fen did not favour particle retention thus since the neolithic yield and storage of om and mm sediment have been marked by human activities initially with high climatic stress but since the middle ages without significant climatic stress

geochemical tools for the stratigraphic correlation of floodplain deposits of the morava river in stražnicke pomoravi czech republic from the last millennium article i nfo the floodplain of the morava river in stra nicke pomoravi south east moravia czech republic contains a very valuable record of regional environmental change which goes back to several thousand years its interpretation has been limited by poor stratigraphic correlation and dating of the sediments we present a geochemical solution to this challenge we studied 8 outcrops of floodplain deposits from 4 localities along a 6 km long part of the current meander belt of the morava river in stra nicke pomoravi using geochemical proxy analyses magnetic susceptibility measurements 14 c dating of wood remnants and sediment micromorphology the proxy methods are based on elemental analysis edxrf and analysis of the cation exchange capacity of clay minerals granulometric analyses provided the basis for lithological and facies assignment of the sediments our geochemical and mineralogical interpretations have further been tested by microstratigraphically studying the optical properties of the fine fraction horizons older than about 3 centuries were 14

impact of mediaeval agriculture on the alluvium in the san river headwaters polish eastern carpathians abstract an abrupt change in sedimentary processes occurs in the alluvium of the san river headwaters in the bieszczady mountains polish eastern carpathians older gravels are overlain with a sharp boundary by an extensive cover of sand and silt which is enriched in wood debris partly burned at the base the spatial distribution of the fine grained alluvium the wood debris composition and radiocarbon ages are best explained by a relatively sudden onset of deforestation and cultivation of the valley bottom and slopes in the middle of the second millennium this corresponds well with palynological archaeological and historical data on the agricultural colonisation of the valley

characterizing large river history with shallow geophysics middle yukon river yukon territory and alaska abstract changes in longitudinal valley fill thickness can provide inferences about fluvial behaviour over millennia increased thickness of channel deposits may reveal climate induced accelerated sediment supply basin subsidence tectonic displacements or rising downstream base level decreases in thickness expressed as terraces may suggest active uplift decreased sediment flux or falling base level within a reach to date methods to characterize valley fills have depended largely on borehole data however recent developments in shallow geophysics make such investigations possible and provide a practical methodology to investigate alluvial rivers we carried out a longitudinal geophysical survey coupled with floodplain chronologies to characterize a 1000 km reach of the middle yukon river between western yukon territory and central alaska ground penetrating radar gpr and electrical resistivity ground imaging ergi profiles along the middle yukon river between central yukon and alaska coupled with channel bottom echo profiles demonstrates that there is little variation in thickness of gravel fill and depth of active scour holes gpr surveys near the white river the largest sediment source in the upper yukon show no significant longitudinal variation in gravel thickness 8 16 m up to near circle alaska 530 km of wandering channels geophysical profiles across the yukon flats sedimentary basin 430 km of braided and wandering channels show an increase in gravel thickness 25 30 m but this is consistent with compaction of underlying lacustrine sediment and maximum depths of contemporary scour holes from the western margin of the yukon flats to the dalton highway bridge 30 km confined valley with no floodplain or braid bars borehole data at the bridge indicates 6 10 m of gravel on bedrock beneath 3 6 m of water floodplain stratigraphy indicates there is little evidence of fluvial aggradation of the middle yukon during the holocene radiocarbon ages from the gravel overbank silt contact near present river level demonstrate a general vertical stability of the river with a period of rapid eolian accumulation during the late pleistocene and early holocene the consistency of gravel fill and scour hole depth and lack of holocene terraces along the 1000 km reach of the yukon indicate that the river has been in a state of mass balance equilibrium of sediment transport input output over the holocene despite massive sediment influxes from the glacial fed white river and crossing major faults variation in valley fill depth is not significant and further the yukon flats reach shows no evidence of bed aggradation during the pleistocene and has probably existed in equilibrium since the late pliocene

late holocene fluvial activity and correlations with dendrochronology of subfossil trunks case studies of northeastern romania abstract the main objective of this paper is to describe the late holocene behaviour of rivers using an interdisciplinary approach combining fluvial geomorphology and subfossil trunk dendrochronology the subfossil wood material collected along the rivers was investigated for dendrometric and dendrochronologic parameters the research methods in these fields helped us to understand the effect of the fluvial environment on riparian trees and their records and helped in reconstructing the riparian palaeoenvironment the study area consists of two rivers with different typologies but comparable sizes the moldova river which features a braided to wandering channel in its lower reach and the siret river which features a sinuous meandering channel along the 100 km long floodplain of the former and the 144 km long floodplain of the latter we found and sampled 77 subfossil trunks of which 26 were subjected to 14 c dating the resulting data consist of floodplain facies mapping data electric resistivity measurements absolute dates and dendrometric and dendrochronologic data the results indicate that during a 100 year period the two rivers were sensitive to climate change and anthropogenic effects particularly a narrowing of the active channel by 76 in the braided channel and 38 in the sinuous meandering channel during the past 3300 3000 ybp the moldova river maintained its braided style whereas the sinuous meandering style has been characteristic of the siret river for the previous 6800 4600 ybp the two distinct fluvial environments are recorded in the dendrometric structure of the trunks buried in the channel fill sediments the braided fluvial environment was more effective in uprooting riparian trees and incorporating them in the floodplain deposits whereas the sinuous meandering style of stream effectively buried tree trunks in lateral accretion lobes absolute and dendrochronologic dating allowed for the reconstruction of timelines of the felling of the trees and estimates of the magnitude of the responsible hydrological event the flood events on the siret river with a recurrence interval of 200 years q max 2500 2800 m 3 s were those most effective in destroying riparian forests and the events on the moldova floods with a 100 year recurrence interval q max 1200 1400 m 3 s were the most effective dendrochronology allowed for identification of wet phases i e 3500 2900 ybp 2200 2075 ybp and 1000 800 ybp and dry phases e g 3200 3150 or 2775 2700 ybp 1400 ybp finally we draw attention to the potential for creating a highly replicable dendrochronological series spanning at least 7000 ybp

fluvial dynamics of the žitava river sw slovakia during the last 45 ka bp and their influence on early bronze age human occupation as part of a geoarchaeological project exploring the early bronze age settlement of fidvar this geomorphologic study explores the fluvial dynamics of the itava river in southwestern slovakia casting light for the first time on the regional river s holocene and late pleistocene development in order to reconstruct the itava s fluvial evolution floodplain deposits were investigated by electrical resistivity tomography selected percussion drillings and ams radiocarbon dating in combination these methods provided a detailed view into the river s history as a result of the climatic variations engendered by the last glacial cycle the fluvial style repeatedly changed between a braided and anastomosing system however during long time periods of the middle and upper plenivistulian the river retained an anastomosing or even meandering style in contrast to central european rivers therefore in agreement with other investigations our results suggest different climatic conditions in the northern pannonian basin from 40 to 20 ka bp during the early and middle holocene a dense vegetation cover dry mesic oak forests led to stable geomorphological conditions and a meandering channel resulted in lateral erosion of the floodplain fringes accumulation of alluvial loamy sediments did not start until the neolithic and has been related to anthropogenic landscape changes similar to other naturally favoured areas central europe finally two reconstructed river positions indicate a considerable lateral fluvial erosion of the early bronze age settlement at fidvar consequently the original settlement area already thought to be the largest in the region was once significantly larger

late quaternary upwelling intensity and east asian monsoon forcing in the south china sea foraminifera from two cores off eastern vietnam and the northwestern philippines where modern summer and winter monsoon driven upwelling occurs in the south china sea respectively were analyzed to evaluate the changes in paleoproductivity and upper water structure over the last 220 000 yr we observed enhanced organic carbon flux and a shoaled thermocline when upwelling intensified off eastern vietnam during interglacial ages and off the northwestern philippines during glacial ages this indicates that the east asian summer monsoon increased while the winter monsoon decreased during interglacial ages particularly the upwelling reached a maximum off eastern vietnam during late marine isotopic stage mis 5 and off the northwestern philippines during mis 2 implying that the summer monsoon decreased gradually since mis 5 while the winter monsoon displayed an opposite trend the variations in upwelling proxies exhibit a distinct cyclicity with frequencies near 41 000 yr and 23 000 yr off eastern vietnam in contrast to a strong frequency peak near 100 000 yr off the northwestern philippines we suggest that the east asian summer monsoon has been forced by changes in solar insolation associated with precession and obliquity while ice volume forcing is probably a primary factor in determining the strength and timing of the east asian winter monsoon but with less important insolation forcing

use of floodplain sediment cores to investigate recent historical changes in overbank sedimentation rates and sediment sources in the catchment of the river ouse yorkshire uk abstract floodplain sediment cores collected from seven sites in the catchment of the river ouse in yorkshire uk have been used to provide information on recent historical changes in both rates of overbank sedimentation and sediment sources the environmental radionuclides 137 cs and unsupported 210 pb have been used to establish chronologies for each core and to estimate average sediment accumulation rates for the last ca 30 and 100 years respectively average sedimentation rates for the individual cores ranged from 0 11 to 1 04 g cm 2 yr 1 in all but one case the estimates of average sedimentation rate during the last ca 30 years for the individual cores are broadly similar to those for the last ca 100 years suggesting that overbank sedimentation rates have been essentially uniform over the longer time period composite fingerprints based on a combination of geochemical and mineral magnetic properties and a numerical mixing model have been used to investigate downcore changes in sediment source in the case of source type most of the cores reflect a primarily topsoil source although there have been periods with increased contributions from subsoil channel bank sources within the ouse basin in general the period commencing in the late 19th and early 20th century and extending through to the 1960s was characterised by increased contributions from topsoil sources however contributions from subsoil channel bank sources have increased over the last few decades the source tracing results relating to sediment contributions from the three main geological topographic zones are in broad agreement with the proportion of the area of the catchment underlain by each rock type temporal variations in the contributions from the three geological topographic zones vary from site to site but for the lower reaches of the river ouse contributions from areas underlain by permian and triassic rocks which mainly outcrop in the vale of york have increased since the turn of the century the changes in sediment source identified are probably a reflection of changes in land use and management and possibly changes in climate these results enable estimates of contemporary suspended sediment fluxes and sources to be placed into a historical context and provide a means of considering the likely impact of potential future changes in land use and climate in the study basin

last glacial interglacial cycle in the evolution of river valleys in southern and central poland abstract the last glacial interglacial cycle is represented usually by several cuts and fills which have formed 2 3 terrace steps from the last cold stage and by two or more fills of lateglacial holocene age their number depends on the size of the river valley and the position in the longitudinal profile the sequence of changes reflects shorter stadial interstadial climatic fluctuations generally aggradation dominates during the cooler phases of the vistulian and during the interpleniglacial the most distinct erosional phases occurred during the change from a more oceanic to a more continental climate before the maximum extension of the ice sheet 25 20 ka bp and during the upper pleniglacial lateglacial transition 15 13 ka bp the second phase coincides with the rapid downcutting in the lower course of the main vistula valley which had been blocked earlier by the scandinavian ice sheet in the holocene aggradation prevailed accelerated by anthropogenic soil erosion it was only in the mountain foreland that shorter lived hydrological changes resulted in well expressed several cuts and fills

halite pseudomorphs after gypsum in bedded anhydrite clue to gypsum anhydrite relationships abstract halite pseudomorphs after gypsum crystals preserve depositional textures and record the early diagenetic history of anhydrite beds in cyclic permian evaporites of the texas panhandle the well documented sedimentologic setting and good preservation of fabrics permit identification of a sequence of diagenetic processes in gypsum gypsum rather than anhydrite was the dominant sulfate precipitated even at salinities near halite saturation large gypsum crystals grew vertically on floors of brine pools surrounded by a matrix of autochthonous transported gypsum sand and silt all gypsum has been diagenetically altered to anhydrite halite but the diagenetic fabrics vary depending on position within regressive evaporite cycles because the composition and texture of the primary sediment were similar throughout the anhydrite bed these different diagenetic fabrics are interpreted as the result of changes in the processes of replacement of gypsum by anhydrite and halite as the shallow burial environment became increasingly saline in the lower parts of anhydrite beds diagenesis in low salinity brines favored obliteration of primary sedimentary structures by formation of nodules in the middle parts of beds introduction of high salinity brine into the shallow burial environment favored alteration of gypsum to anhydrite and preservation of pseudomorphs after large gypsum crystals at the top of anhydrite beds introduction of halite saturated brines into gypsum sediments on the floor of the brine pool resulted in pervasive replacement of gypsum by halite petrogr phic relationships indicate that most or all of the primary gypsum was altered to anhydrite in the very shallow 2 m burial environment under the influence of saline diagenetic brines

circumgranular bassanite in a gypsum crust from eastern algeria a potential palaeosurface indicator detrital sand grains are surrounded by thin bassanite coatings in the upper part of a coarse crystalline gypsum crust from the algerian sahara the bassanite developed by topotactic replacement of the surrounding gypsum in the absence of a liquid phase heating experiments using a gypsum crystal with sand inclusions produced similar patterns and textures in one experiment bassanite developed around quartz and carbonate grains but not along the sides of the heated gypsum crystal this is the result of differences in heat capacity between gypsum quartz and calcite bassanite formation in the crust from algeria was not controlled by differences in thermal properties instead the bassanite apparently formed under conditions of thermal equilibrium the occurrence of bassanite as circumgranular coatings in the crust is interpreted as being related to the availability of submicroscopic space along the contact between the gypsum cement and the enclosed sand grains the presence of coatings of this type or derived relict features is a potential criterion for the recognition of palaeosurfaces

impacts of typhoon megi 2010 on the south china sea in october 2010 typhoon megi induced a profound cold wake of size 800 km by 500 km with sea surface temperature cooling of 8 c in the south china sea scs more interestingly the cold wake shifted from the often rightward bias to both sides of the typhoon track and moved to left in a few days using satellite data in situ measurements and numerical modeling based on the east asian seas nowcast forecast system easnfs we performed detailed investigations to obtain realistic typhoon strength atmospheric forcing the easnfs applied typhoon resolving weather research and forecasting wrf model wind field blended with global weather forecast winds from the u s navy operational global atmospheric prediction system nogaps in addition to the already known impacts from the slow typhoon translation speed and shallow pre exiting ocean thermocline we found the importance of the unique geographical setting of the scs and the ne monsoon as the event happened in late october ne monsoon already started and contributed to the southwestward ambient surface current together with the topographic effect the cold wake shifted westward to the left of megi s track it was also found that megi expelled waters away from the scs and manifested as a gush of internal kelvin wave exporting waters through the luzon strait the consequential sea level depression lasted and presented a favorable condition for cold dome development fission of the north south elongated cold dome resulted afterward and produced two cold eddies that dissipated slowly thereafter

sub milankovitch climatic cycles in holocene stalagmites from sauerland germany calcitic stalagmites from caves in the sauerland germany prove the existence of sub milankovitch cycles in precipitation during the last 6000 yr the 18o record dated with th u is interpreted as an indicator of paleohumidity spectral analysis of 18o from 6000 a bp up to the recent top of a stalagmite from the atta cave yields statistically significant peaks at 1450 117 64 and 57 a additionally we find a good correlation of the stalagmite s 18o and 14c from european tree rings the 1450 a cycle in the stalagmite probably is analogous to the pervasive millennial scale climate cycle described by bond et al science 278 1997 1257 1266 294 2001 2130 2136 derived from the amount of ice rafted debris in deep sediments from the north atlantic our results suggest that the centennial to millennial shifts observed in the north atlantic are accompanied by synchronous shifts of the climate in northern and central europe which most probably can be attributed to solar irradiation variations

geochemical traces of flood layers in the fluvial sedimentary archive implications for contamination history analyses abstract we studied three cores from a well dated sediment archive from an oxbow lake of the river morava czech republic using a high resolution 1 cm multiproxy stratigraphic analysis and a concentration of selected heavy metals the objective was to investigate how the vertical distribution of pollutants could be affected by episodic flood sedimentation in archives with high sedimentation rates stratigraphic proxies magnetic susceptibility ms x ray densitometry and visible light diffuse reflectance spectrometry supported by grain size analyses enabled us to identify relatively coarse grained flood layers and correlate them in the proximal to distal direction in the oxbow lake delta a correlation of the flood layers with the time series of the river discharge was used to improve the age model based primarily on 137cs dating the refined age model is nonlinear and shows periods of lower and higher sediment accumulation rates which coincided with periods of lower and higher frequency of floods in the river respectively concentrations of most heavy metals normalized to lithogenic aluminium revealed vigorous short term variation related to floods whose magnitude exceeds that of long term trends there is a substantial risk that temporal contamination trends even if normalized to lithogenic elements can be strongly influenced by facies which may lead to potential misinterpretations element normalizing to ms which proved to be a good proxy of grain size provided smoother long term trends whose interpretation was less affected by short term variations the long term trends exhibit decreasing concentrations of most heavy metals for the last 25 years most notably between 1987 and 1992 these historical patterns correspond well to the significant improvement in environmental pollution reported elsewhere in central europe in contrast concentrations of na have systematically increased up until the present partly being driven by the widespread use of de icing salt for winter road treatment

pollution distribution in floodplain structure visualised by electrical resistivity imaging in the floodplain of the litavka river the czech republic abstract shape and position of modern polluted sediment bodies in the floodplain internal structure can provide insight into past and future erosional deposition behaviour of fluvial systems extensive field works needed for such studies can be mitigated by the use of geophysical imaging originally developed for engineering practice but still rather sparsely used in floodplain research we demonstrate the performance of electrical resistivity tomography ert dipole electromagnetic profiling demp and x ray fluorescence spectroscopy for identification of subsurface sediment bodies of contrasting lithology age and pollution status we found minor remnants of unpolluted ancient floodplain segments that would likely have been overlooked in arbitrary blind sampling pollution chemostratigraphy of floodplains based on the concentrations of certain risk elements can be affected by post depositional migration we thus identified signatures related to mining and smelting that are carried by coarser particles gangue fly ash not expected to undergo post depositional translocations in alluvium the local enrichment factor of zr lef zr and mass specific magnetic susceptibility the lef zr differentiated pre mining floodplain sediments which originated from erosion of zr rich catchment loess soils from zr poor gangue derived material exhibits a step like increase above the threshold value of approximately 25 10 8 m3 kg in severely polluted sediments we assign that step to the replacement of charcoal and wood by coke in smelting technology during the late 19th century the shape of the unpolluted sedimentary bodies as well as bodies of historically changing pollution extent indicate considerable recent lateral river instability a mild aggradation flattened the floodplain surface and prevented the identification of buried sedimentary bodies by surface topography but did not restrict the power of the geophysical imaging

a depositional model for the terminal neoproterozoic early cambrian ara group evaporites in south oman six evaporite carbonate sequences are recognized in the terminal neoproterozoic early cambrian ara group in the subsurface of oman individual sequences consist of a lower evaporitic part that formed mainly during a lowstand systems tract overlying platform carbonates contain minor amounts of evaporites and represent transgressive and highstand systems tracts detailed sedimentological and geochemical investigation of the evaporites allowed reconstruction of the depositional environment source of brines and basin evolution at the beginning of the evaporative phase prograding succession a shallow water carbonate ramp gradually evolved into a series of shallow sulphate and halite salinas minor amounts of highly soluble salts locally record the last stage of basin desiccation this gradual increase in salinity contrasts sharply with the ensuing retrograding succession in which two corrosion surfaces separate shallow water halite from shallow water sulphate and shallow water sulphate from relatively deeper water carbonate respectively these surfaces record repeated flooding of the basin dissolution of evaporites and stepwise reduction in salinity final flooding led to submergence of the basin and the establishment of an open water carbonate ramp marine fossils in carbonates and bromine geochemistry of halite indicate a dominantly marine origin for the brines the ara group sequences represent a time of relatively stable arid climate in a tectonically active basin strong subsidence allowed accommodation of evaporites with a cumulative thickness of several kilometres while tectonic barriers simultaneously provided the required restricted conditions subsidence allowed evaporites to blanket basinal and platform areas the study suggests a deep basin shallow water model for the evaporites

sediment accumulation rates and high resolution stratigraphy of recent fluvial suspension deposits in various fluvial settings morava river catchment area czech republic abstract we present a comprehensive study concerning sedimentary processes in fluvial sediment traps within the morava river catchment area czech republic involving three dammed reservoirs four meanders and oxbow lakes and several natural floodplain sites the objective of the study was to determine sediment accumulation rates sar estimate erosion rates calculating these using a combination of the 137 cs method and historical data another purpose of this study was to provide insight into changing erosion and accumulation rates over the last century extensive water course modifications were carried out in the morava river catchment area during the twentieth century which likely affected sedimentation rates along the river course other multiproxy stratigraphic methods x ray densitometry magnetic susceptibility and visible light reflectance spectrometry were applied to obtain additional information about sediment infill sediment stratigraphy revealed distinct distal to proximal patterns especially in reservoirs granulometrically silts and sandy silts prevailed in sediments oxbow lakes and meanders contained larger amounts of clay and organic matter which is the main difference between them and reservoirs pronounced 137 cs peaks were recorded in all studied cores maximum 377 bq kg 1 thus indicating chernobyl fallout from 1986 or older events calculated sediment accumulation rates were lowest in distal parts of reservoirs 0 13 0 58 cm y and floodplains 0 45 0 88 cm y moderately high rates were found in proximal parts of reservoirs and oxbow lakes 2 27 4 4 cm y and the highest rates in some oxbow lakes located near the river 6 8 cm y the frequency of the inundation still can be high in some natural areas as in the litovelske pomoravi protected area whereas the decreasing frequency of the inundation in other modified parts can contribute to a lower sedimentation rate the local effects such as difference between sars in oxbow lakes and reservoirs different grain size distribution in both systems and high variability in thickness of their proximal and distal parts play a crucial role in the analysis of regional accumulation rates local effects are much stronger than regional effects such as rainfall and land use combined with the low resolution of time scales usually only three datums are available reservoir construction datum 137 cs fallout event and top of sediment these effects may obscure the general trends of regionally increasing or decreasing net sars making the analysis of erosion rates from the sedimentary record an extremely difficult task

climatic versus human impact on the holocene sedimentation in river valleys of different order examples from the upper dnieper basin belarus records from floodplain deposits in selected river valleys of the dnieper river basin belarus were studied to reconstruct the phases of natural and anthropogenic environmental changes in the holocene sediment archives in the main valley and its four tributaries of different orders were studied by means of lithological and geochemical methods including grain size analysis x ray fluorescence analysis spectral analysis spore and pollen analyses and radiocarbon dating some differences in the response of different order fluvial systems to climate changes and human impact have been revealed fluvial deposits in the dnieper valley and in first order valleys contain records on the regional scale natural environmental changes while human impact is clearly pronounced only in deposits of the last millenium fluvial deposits in the valleys of second order record river evolution only since the neoholocene at the same time the lacustrine or carbonate freshwater deposits in these valleys contain the records of environmental changes in the entire holocene changes in the sequence and composition of fluvial deposits due to human impact occurred in high order valleys almost 2000 years later since 500 years bp as compared with pollen data

restratification of the upper ocean after the passage of a tropical cyclone a numerical study abstractthe role of baroclinic instability in the restratification of the upper ocean after the passage of a tropical cyclone tc is determined by means of numerical simulations using a regional ocean model the regional ocean modeling system roms a high resolution three dimensional simulation that includes the process of baroclinic instability and is initialized with moderate amplitude eddy structures reproduces the satellite observed decay rate of the tc induced sea surface temperature sst anomaly and is also in qualitative agreement with published observations after the passage of hurricane fabian in 2003 that showed decaying cold and warm anomalies located in the climatological mixed layer cml and upper thermocline respectively the model ocean is restratified after approximately one month with a net heat gain in the water column due to anomalous air sea heat fluxes the model shows however that vertical heat fluxes associated with baroclinic instability dominate over air sea heat fluxes i

spatial and temporal characterization of sea surface temperature response to tropical cyclones abstractthe spatial structure and temporal evolution of the sea surface temperature sst anomaly ssta associated with the passage of tropical cyclones tcs as well as their sensitivity to tc characteristics including tc intensity and translation speed and oceanic climatological conditions represented here by latitude are thoroughly examined by means of composite analysis using satellite derived sst data the magnitude of the tc generated ssta is larger for more intense slower moving and higher latitude tcs and it occurs earlier in time for faster moving and higher latitude storms the location of maximum ssta is farther off the tc track for faster moving storms and it moves toward the track with time after the tc passage the spatial extension of the cold wake is greater for more intense and for slower moving storms but its shape is quite independent of tc characteristics consistent with previous studies the calculations show that the mean ssta over a tc centered box nearly linearly corre

palaeohydrological evolution and implications for palaeoclimate since the late glacial at laguna de fuente de piedra southern spain abstract here we present a terrestrial multi proxy record of late quaternary environmental changes in the southern iberian peninsula covering approximately 30 ka this sedimentary record originates from a saline playa lake laguna de fuente de piedra hosted within a complex geological setting dominated by triassic claystones and evaporites jurassic carbonates and miocene deposits leading to a complex hydrogeological setting dissolution of evaporites in the catchment and intense evaporation are responsible for saline waters fluctuating in the basin thus salinity as palaeohydrological proxy requires a decoupling of internal and external hydrogeochemical processes the greatest accumulation of evaporites in the lfp late pleistocene holocene record coincides with a more humid or at least less evaporative period based on multi proxy data we describe five lacustrine lithofacies 2 5 and fluvial deposits 1 from sediment cores the proposed conceptual lake margin model contains three main lake water stages repeated within the sedimentary succession and building up the characteristic lithofacies lake water stages refer to a flooding stage influx outflux high water stage influx outflux and low water stage influx

human induced overbank sedimentation in the foreland of the eastern sudety mountains analysis of a 2 3 m thick vertical sequence of fine grained overbank alluvial sediments on the foreland of the eastern sudety mountains reveals that these sediments resulted from human land use changes following the holocene climatic amelioration the first farmers and breeders migrating northward from the danube basin crossed the limit of the sudety carpathians and settled the loess covered glubczyce plateau about 7000 years ago the farming and breeding tribes of early bronze age created the compact settlement structure of the lusitian culture here about 1600 1300 years bc the first forest clearance began at this time slavic settlements existed here in early medieval times from at least the 6th and 7th centuries onwards later economic expansion of the opole duchy and increased population density up to 20 30 persons km2 caused an increase in soil erosion and flood amplitudes investigation of small radius palaeomeander infills adjacent to the main channels indicates that fossilization of organic material that filled these palaeochannels started in early medieval times due to more frequent flood waves and an increased rate of overbank sedimentation in channel undercuts older alluvia have well developed cambic gleyo fluvisols while younger homogenous alluvia do not have traces of soil processes analysis of heavy metal concentrations in older and younger deposits indicates very similar concentrations of cadmium copper lead and zinc this indicates that the source of these alluvia was the transfer of sediments from the mainly deforested part of the drainage basin therefore since at least early medieval times and possibly even earlier the glubczyce plateau has been a deforested region despite the mountainous character of the headwater area of rivers in the eastern sudety foreland sediment transfer from sub mountainous loess covered uplands induced by human activity is clearly marked in the granulometric and geochemical properties of the vertical sequences of overbank deposits copyright 2002 john wiley sons ltd

late mississippian limestone sedimentary environment in southern pembrokeshire bullslaughter bay wales evidence of meteoric diagenesis and hypersaline features bullslaughter bay in southern pembrokeshire uk exposes sections of upper mississippian limestone strata in many places the rock suffered an isovolumetric alteration during a period of sea level oscillations we used multiple approaches to study the weathered rocks combining sedimentological petrographic and isotopic compositions 18o and 13c values two main microfacies are recognized i packstones grainstones characteristic of an open marine shallow subtidal intertidal environment with a high degree of agitation slightly elevated salinity and temporary subaerial exposure and ii mudstones wackestones in a lagoonal setting and intertidal or supratidal environments with a pedogenetic influence in both cases a complex diagenetic story which started early in a meteoric environment induced a strong alteration producing loose sediments in place of the parent rock calcretization at or near the sediment surface in the vadose zone was one of the most widespread diagenetic modes it could be associated with beachrocks carbon and oxygen stable isotope analyses from more or less weathered limestones support the petrographic data they show non marine values with 13c ranges of from 2 13 to 1 75 and 18o from 6 05 to 4 66 these values are systematically lower than those of the middle carboniferous seawater some periods of low sea level and subaerial exposure allowed gypsum to form neoformation of euhedral quartz by probable replacement after sulfate and halite pseudomorphs after gypsum in a hypersaline environment are documented for the first time in southern pembrokeshire the studied weathered limestones present a complex diagenetic evolution related to sea level oscillations in a range of hot and contrasting seasonal climates

past hydrological events reflected in the holocene fluvial record of europe abstract a comprehensive database of radiocarbon dated fluvial units in great britain poland and spain has been compiled to investigate the relationship between environmental change flooding and holocene river dynamics following the methodology recently developed by macklin and lewin macklin m g lewin j 2003 river sediments great floods and centennial scale holocene climate change journal of quaternary science 18 101 105 radiocarbon dates in fluvial sequences that coincide with a modification in sedimentation rate or style have been highlighted allowing geomorphologically significant changes in holocene river activity to be identified data analysis has been undertaken at both national and sub national scales and on catchments of different size type and land use history multiple phases of higher flood frequency characterized by accelerated erosion and sediment deposition on floodplains are recognized and compared with a range of climate proxies the relative and varying roles of climate and land use on river dynamics are considered and the value of the database for reconstructing past hydrological events as well as for predicting river response to future environmental change is assessed

origin and diagenetic evolution of gypsum and microbialitic carbonates in the late sag of the namibe basin sw angola abstract ephemeral evaporitic conditions developed within the uppermost part of the transgressive late sag sequence in the namibe basin sw angola leading to the formation of extensive centimetre to metre thick sulphate bearing deposits and correlative microbialitic carbonates rich in pseudomorphs after evaporite crystals the onshore pre salt beds examined in this study are located up to 25 m underneath the major mid aptian evaporitic succession which is typified at the outcrop by gypsiferous bambata formation and in the subsurface by the halite dominated loeme formation carbonate evaporite cycles mostly occur at the top of metre thick regressive parasequences which progressively onlap and overstep landward the former faulted rift topography or fill major pre salt palaeo valleys the sulphate beds are made up of alabastrine gypsum associated with embedded botryoidal nodules dissolution related gypsum breccia and are cross cut by thin satin spar gypsum veins nodular and fine grained fabrics are interpreted as being diagenetic gypsum deposits resulting from the dissolution and recrystallisation of former depositional subaqueous sulphates whereas gypsum veins and breccia result from telogenetic processes the carbonates display a broader diversity of facies characterised by rapid lateral variations along strike thin dolomitic and calcitic bacterial mediated filamentous microbialitic boundstones enclose a broad variety of evaporite pseudomorphs and can pass laterally over a few metres into sulphate beds dissolution related depositional breccias are also common and indicate early dissolution of former evaporite layers embedded within the microbialites sulphate and carbonate units are interpreted as being concomitantly deposited along a tide dominated coastal supra to intertidal sabkha and constitute high frequency hypersaline precursor events prior to the accumulation of the giant saline mid aptian bambata and loeme formations petrographic and geochemical analyses reveal successive dissolution recrystallisation and cementation phases that occurred during burial uplift and exhumation implying a complex diagenetic evolution of both gypsum and carbonates influenced by pore fluids of diverse composition which distinctly varied from meso to telogenetic domains

satellite observations of modulation of surface winds by typhoon induced upper ocean cooling 1 two remote sensing data sets the tropical rainfall measurement mission sea surface temperature sst and the nasa quikscat ocean surface wind vectors are analysed to study ocean atmosphere interactions in cold sst regions formed in the trail of two typhoon events anomalously cold sst patches up to 6 c below the surrounding warm tropical ocean sst are found along the trail of typhoon tracks as cold deep waters are entrained up to the mixed layer due to typhoon forcing in both typhoon events significant and systematic weakening of surface wind speed is found over cold sst patches relative to surface wind speed in surrounding regions the wind speed anomalies disappear as the patches recover to the level of the surrounding sst the results are consistent with the mechanism proposed by wallace et al that surface winds are modulated by sst via stability as wind within the well mixed boundary layer moves over the cold patch boundary layer stability increases vertical mixing is suppressed and the vertical wind shear increases reduction in surface wind speed is caused in particular our result shows that this mechanism can act on relatively small spatial 100 km and short 1 day time scales

mid to late holocene climate change an overview the last 6000 years are of particular interest to the understanding of the earth system because the boundary conditions of the climate system did not change dramatically in comparison to larger glacial interglacial changes and because abundant detailed regional palaeoclimatic proxy records cover this period we use selected proxy based reconstructions of different climate variables together with state of the art time series of natural forcings orbital variations solar activity variations large tropical volcanic eruptions land cover and greenhouse gases underpinned by results from general circulation models gcms and earth system models of intermediate complexity emics to establish a comprehensive explanatory framework for climate changes from the mid holocene mh to pre industrial time the redistribution of solar energy due to orbital forcing on a millennial timescale was the cause of a progressive southward shift of the northern hemisphere nh summer position of the intertropical convergence zone itcz this was accompanied by a pronounced weakening of the monsoon systems in africa and asia and increasing dryness and desertification on both continents the associated summertime cooling of the nh combined with changing temperature gradients in the world oceans likely led to an increasing amplitude of the el nin o southern oscillation enso and possibly increasingly negative north atlantic oscillation nao indices up to the beginning of the last millennium on decadal to multi century timescales a worldwide coincidence between solar irradiance minima tropical volcanic eruptions and decadal to multi century scale cooling events was not found however reconstructions show that widespread decadal to multi century scale cooling events accompanied by advances of mountain glaciers occurred in the nh e g in scandinavia and the european alps this occurred namely during the little ice age lia between ad w1350 and 1850 when the lower summer insolation in the nh due to orbital forcing coincided with solar activity minima and several strong tropical volcanic eruptions the role of orbital forcing in the nh cooling the southward itcz shift and the desertifi cation of the sahara are supported by numerous model simulations other simulations have suggested that the fingerprint of solar activity variations should be strongest in the tropics but there is also evidence that changes in the ocean heat transport took place during the lia at high northern latitudes with possible additional implications for climates of the southern hemisphere sh

late quaternary landscape evolution of the upper dnister valley western ukraine abstract the broad and flat valley of the upper dnister in western ukraine is characterized by a complex setting of ecotopes and a relatively natural state of floodplain dynamics excellent geo archives extended peat bogs and postglacial river terraces document late quaternary landscape evolution with special regard to changes in fluvial morphodynamics vegetation and human impact the terraces were studied by detailed geomorphological mapping as well as sedimentological and pedological analyses in connection with information from historical maps vegetation history was studied by palynological methods in combination with radiocarbon dating two late pleistocene nt1 and nt2 and seven holocene h1 h7 river terraces are evident the ecological transformation during the period of climatic warming at the end of the last glacial maximum lgm caused the most significant change in runoff and sediment load as well as in the vegetation cover the dnister changed from a braided to a meandering river system it was soon after the spreading of postglacial forests with an increasing dominance of broadleaved trees that the pollen diagrams reflected the first signs of anthropogene influence intensified agricultural land use since the iron age is mirrored in the increasing amount of herbaceous pollen as well as the rise of fluvial sediment redeposition modern hydraulic engineering on the dnister has caused visible transformations because of these impacts the stability of the upper dnister ecosystem has decreased significantly and is now highly sensitive to environmental change

the history of soil erosion and fluvial deposits in small catchments of central europe deciphering the long term interaction between humans and the environment a review abstract during the last few decades many case studies focused on the dynamics of fluvial systems in response to hillslope erosion land use impact and climate changes this paper will review the current state of knowledge of the dynamics of past soil erosion and gullying in small catchments

summer upwelling in the south china sea and its role in regional climate variations seasonal and interannual variations of summer upwelling off the south vietnam coast and the offshore spread of cold water are investigated using a suite of new satellite measurements in summer as the southwesterly winds impinge on annam cordillera a north south running mountain range on the east coast of indochina a strong wind jet occurs at its southern tip offshore east of saigon resulting in strong wind curls that are important for ocean upwelling off the coast in july and august an anticyclonic ocean eddy develops to the southeast advecting the cold coastal water offshore into the open south china sea scs the center of this cold filament is located consistently north of the wind speed maximum indicating that open ocean upwelling helps to cool the ocean surface corroborating evidence for the cold filament is found in ocean color observations that reveal a collocated tongue of high chlorophyll concentration the development of this cold filament disrupts the summer warming of the scs and causes a pronounced semiannual cycle in sst moreover the cold filament is an important player in interannual variability in the summer scs in 1998 the cold filament and mid summer cooling never took place giving rise to a strong basin wide surface warming interannual sst variance has a local maximum over the climatological cold filament and is much greater than the variance over the adjacent indian and western pacific oceans a cold filament index is constructed which displays significant lagged correlation with sst in the eastern equatorial pacific and indian oceans indicative of a teleconnection from el nino

tropical cyclone induced ocean response a comparative study of the south china sea and tropical northwest pacific abstractthe thermocline shoals in the south china sea scs relative to the tropical northwest pacific ocean nwp as required by geostrophic balance with the kuroshio the present study examines the effect of this difference in ocean state on the response of sea surface temperature sst and chlorophyll concentration to tropical cyclones tcs using both satellite derived measurements and three dimensional numerical simulations in both regions tc produced sst cooling strongly depends on tc characteristics including intensity as measured by the maximum surface wind speed translation speed and size when subject to identical tc forcing the sst cooling in the scs is more than 1 5 times that in the nwp which may partially explain weaker tc intensity on average observed in the scs both a shallower mixed layer and stronger subsurface thermal stratification in the scs contribute to this regional difference in sst cooling the mixed layer effect dominates when tcs are weak fast moving and or small

forced and internal variability of tropical cyclone track density in the western north pacific abstractforced interannual to decadal variability of annual tropical cyclone tc track density in the western north pacific between 1979 and 2008 is studied using tc tracks from observations and simulations by a 25 km resolution version of the gfdl high resolution atmospheric model hiram that is forced by observed sea surface temperatures ssts two modes dominate the decadal variability a nearly basinwide mode and a dipole mode between the subtropics and lower latitudes the former mode links to variations in tc number and is forced by sst variations over the off equatorial tropical central north pacific whereas the latter might be associated with the atlantic multidecadal oscillation the interannual variability is also controlled by two modes a basinwide mode driven by sst anomalies of opposite signs located in the tropical central pacific and eastern indian ocean and a southeast northwest dipole mode connected to the conventional eastern pacific enso the seasonal evolution of the enso effect

neogene evaporites in desert volcanic environments atacama desert northern chile the upper miocene and pliocene evaporite deposits of the atacama desert of northern chile hilaricos and soledad formations are among the few nonmarine evaporites in which aridity not only formed the deposits but has also preserved them almost unaltered under near surface conditions these deposits are largely composed of displacive ca sulphate and halite together with minor amounts of glauberite thenardite and polyhalite however at the base and top of these deposits there are also beds of gypsum crystal pseudomorphs that originally formed as free growth forms within shallow brine bodies rather than as displacive sediments the halite is present as interstitial cement displacive cubes and shallow water bottom growth chevron crusts most of the calcium sulphate is presently anhydrite pseudomorphous after gypsum that was the primary depositional sulphate mineral the secondary anhydrite formed under early diagenetic conditions after slight burial some metres resulting from the effect of strongly evolved pore brines the anhydrite has been preserved without rehydration during late diagenetic and exhumation stages on account of the arid environment of the atacama desert both the hilaricos and the soledad formations contain geochemical markers indicating that these neogene evaporites had a largely non marine origin bromine content in the halite is very low few p p m indicating neither a sedimentological relation with sea water nor the likelihood of direct recycling of prior marine halites moreover the d 34 s of sulphates 4ae5 to 9 also reflects a non marine origin with a strong volcanic influence although some recycling of mesozoic marine sulphates cannot be ruled out d 34 s of dissolved sulphate from hot springs and streams in the area commonly displays positive values 2 to 10 leaching of oxidized sulphur and chlorine compounds from volcanoes and epithermal ore bodies very common in the associated drainage areas have been the main contribution to the accumulation of evaporites the sedimentary and diagenetic evolution of the hilaricos and soledad evaporites based on lithofacies analysis provides information about the palaeohydrological conditions in the central depression of northern chile during the neogene in addition the diagenesis and exhumation history of these evaporites confirms the persistence of strongly arid conditions from late miocene until the present a final phase of tectonism took place permitting the internal drainage to change and open to the sea resulting in dissolution and removal of a significant portion of these deposits despite the extensive dissolution the remaining evaporites have undergone little late exhumational hydration

holocene fluctuations of lake levels in the french jura and sub alpine ranges and their implications for past general circulation patterns temperature and precipitation variations reflected in lake level fluctuations in the french jura and pre alps during the last nine millennia are qualitatively assessed by reference to 1 climatic oscillations reconstructed in the alps and 2 modern processes behind alpine tree limit variations the summer season and mainly the late summer appears to have a deterministic impact on the holocene environment correlations between palaeoclimatic proxy data recorded in the north atlantic area from high and middle latitudes and climatic dynamics illustrated by the little ice age and the recent warming suggest 1 the existence of climatic oscillations due to varying solar activity superimposed on larger plurimillennial climatic trends and 2 that these minor climatic phases correspond with two main types of general circulation pattern alternating over western europe during the last six millennia the climatic deteriorations correspond with cooling at high latitudes inducing a stronger thermal grad

a neolithic yew bow in the polish carpathians evidence of the impact of human activity on mountainous palaeoenvironment from the kamiennik landslide peat bog abstract a unique artefact the fragment of a bow made of yew wood indicating the hunting activity of prehistoric man was found within the sediments of the landslide peat bog at the depth of 330 cm formed on the mt kamiennik polish flysch carpathians the datings of this artefact using 14 c method at ca 3790 3380 cal bc indicate its connection with the activity of the neolithic man related to the funnel beaker culture in the sequence of the peat bog deposits formed since the atlantic phase the palaeoclimatic changes of the middle and late holocene as well as traces of human impact in these and subsequent periods were recorded and analysed using palynological macrofossils lithological methods and dated with radiocarbon palaeoenvironmental changes identified in the peat horizon bearing the artefact were marked by the delivery of minerogenic high energy deposits with charcoal to the peat bog as well as distinct changes of plant communities these phenomena confirm a significant human impact caused by the prehistoric man on landslide areas on the other hand the study confirms significant importance of climatic condition for human activity and proves that landslide peat bog deposits are very sensitive records of palaeoenvironmental changes the archaeological artefact essentially supplements the results of our interdisciplinary palaeoenvironmental study it is one of the rare neolithic bows found in the area of europe till now

holocene river activity analysing 14c dated fluvial and colluvial sediments from germany records of fluvial dynamics in response to long term changes of climate and land use impacts are rare therefore cumulative probability functions cpfs of 401 14c ages originating from german rivers and hillslopes were compiled to reconstruct phases of increased geomorphic activity and stability during the holocene an improved analytical method is suggested to normalise cpfs and eliminated the effects of wiggles of the calibration curve and the young age bias nine periods of activity are identified peaking at 7050 6250 5525 3690 2250 1350 820 325 bc and since 875 ad and are compared with climatic palaeohydrological and human impact proxy data until 2250 bc events of geomorphic activity are mainly coupled to wetter and or cooler climatic phases due to growing population and intensive agricultural activities during the bronze age the increased geomorphologic activity between 1300 and 820 bc cannot unequivocally be related to climate since 875 ad the growing population density is considered as the major external forcing differential geomorphic activity of hillslopes and floodplains suggest that the hillslope channel coupling during the holocene is mainly controlled by human impact with a strong increased coupling after 1500 bc

medieval accumulation in the upper dniester river valley the role of human impact and climate change in the carpathian foreland research in the valleys of upper dniester strvja and stryj rivers in the eastern carpathian foreland documents the occurrence of 3 4 holocene floodplain terraces and several alluvial fills dating back to the late vistulian and the atlantic as well as the periods 3500 3000 bp 1850 1250 cal bc 2200 1700 bp 360 cal bc 390 cal ad 5th 6th 10th 12th and 14th 16th centuries ad flood phases distinguished in the upper dniester drainage basin correlate well with previously established phases of enhanced fluvial activity in the valleys of upper vistula the wisloka and the san in the western carpathian foreland an episode of tree fall during the 5th 6th century floods is the most conspicuous and is linked to the beginning of a wet climate phase 1500 1350 cal bp subsequent phases of greater fluvial activity from the 10th to the 12th and from the 14th to the 16th centuries record increasing human activity as well as correlation with wet and cool climate phases the first half of the 11th century and the beginning of the little ice age fluvial accumulation processes along the longitudinal profile of the upper dniester valley were affected not only by human activity and more humid climate phases but also by diverse neotectonic movements

past hydrological events reflected in holocene history of polish rivers abstract a database of 335 radiocarbon dates from holocene fluvial sediments in poland has been compiled each sample is characterized by 25 parameters all samples were grouped into one of 7 regions characterized by hydrological regime and one of 8 depositional environments statistical analysis was used to enhance the palaeoenvironmental data and 17 phases may be distinguished 10 of which have a distinct sharp peak abandoned paleochannels 149 dates clearly reflect the major wetter phases of the holocene an opposite picture is presented by overbank aggradation 86 dates connected mainly with expansion of agriculture preliminary correlations are made on peat bog records changes in vegetation lake water level rates calcareous tufa and speleothems growth landslides phases and debris flow phases these show many convergences explained by climatic fluctuations during the holocene

surprisingly small increase of the sedimentation rate in the floodplain of morava river in the stražnice area czech republic in the last 1300 years abstract sediment profiles from the floodplain of morava river in the czech republic have been collected from exposed river banks 4 6 m long sections and cores 2 4 m deep and investigated using a set of geochemical proxies validated by granulometry and conventional geochemical analysis outlined in our previous paper the work was conducted to evaluate the increase in sedimentation rate during medieval and modern time periods correlation of sediments along the current channel belt allows identification of two most important synchronous changes in the channel structure over the past 1300 years in the 13th century and at the end of the 16th century these changes could be related to central european climatic extremes rather than to land cover land use practises analysis of the pollen record in peaty deposits at the floodplain edge allows excluded dramatic deforestation in medieval times maps of the area from the last five centuries revealed direct and indirect signs of past avulsions and clearly show how the original multichannel system was transformed into a single meandering channel in the early 20th century the extrapolated aggradation rate net vertical accretion of floodplain fines except for levee sediments increased from 0 2 0 3 cm year in 700 ad to 0 3 0 4 cm year in 2000 ad depending on the grain size of the sediment this is the smallest yet reported enhancement of siliclastic deposition although morava river watershed has been intensively used for agriculture and its land cover has changed in a manner similar to west and central european rivers