precipitation driven decadal scale decline and recovery of wetlands of lake pannon during the tortonian high resolution pollen and dinoflagellate analyses were performed on a continuous 98 cm long core from tortonian deposits of lake pannon in the styrian basin in austria the sample distance of 1 cm corresponds to a resolution of roughly one decade allowing insights into environmental and climatic changes over a millennium of late miocene time shifts in lake level surface water productivity on a decadal to centennial scale can be explained by variations of rainfall during the tortonian climatic optimum related to negative fine scale shifts of mean annual precipitation shoreline vegetation belts reacted in an immediate replacement of poaceae by cyperaceae as dominant grasses in the marshes fringing the lake in contrast to such near synchronous ecosystem responses to precipitation a delayed lake level rise of 4 6 decades is evident in the hydrological budget of lake pannon this transgression caused by a precipitation increase up to 1200 mm yr resulted in a complete dieback of marshes simultaneously open water dinoflagellates such as impagidinium took over in the brackish lagoon and fresh water dinoflagellates disappeared as soon as the rainfall switched back to moderate levels of 1100 1200 mm yr the rise of the lake level slowed down the marsh plants could keep up again and the former vegetation belts became re established thus mean annual precipitation more than temperature was the main driving force for high frequency fluctuations in the tortonian wetlands and surface water conditions of lake pannon such high resolution studies focusing on tortonian decadal to centennial climate change will be crucial to test climate models which try to compare the tortonian models with predictions for future climate change

the last reconnection of the marmara sea turkey to the world ocean a paleoceanographic and paleoclimatic perspective during the late glacial marine isotope stage 2 the marmara sea transformed into a brackish lake as global sea level fell below the sill in the dardanelles strait a record of the basin s reconnection to the global ocean is preserved in its sediments permitting the extraction of the paleoceanographic and paleoclimatic history of the region the goal of this study is to develop a high resolution record of the lacustrine to marine transition of marmara sea in order to reconstruct regional and global climatic events at a millennial scale for this purpose we mapped the paleoshorelines of marmara sea along the northern eastern and southern shelves at cekmece prince islands and imrali using data from multibeam bathymetry high resolution subbottom profiling chirp and ten sediment cores detailed sedimentologic biostratigraphic foraminifers mollusk diatoms x ray fluorescence geochemical scanning and oxygen and carbon stable isotope analyses correlated to a calibrated radiocarbon chronology provided evidence for cold and dry conditions prior to 15 ka bp warm conditions of the bolling allerod from 15 to 13 ka bp a rapid marine incursion at 12 ka bp still stand of marmara sea and sediment reworking of the paleoshorelines during the younger dryas at 11 5 to 10 5 ka bp and development of strong stratification and influx of nutrients as black sea waters spilled into marmara sea at 9 2 ka bp stable environmental conditions developed in marmara sea after 6 0 ka bp as sea level reached its present shoreline and the basin floors filled with sediments achieving their present configuration

holocene marine transgression in the black sea new evidence from the northwestern black sea shelf abstract for two decades the timing and rate of holocene marine transgression and the level of the black sea prior to the transgression has been the focus of many geological palaeoecological and archaeological studies the potential importance of confirming or rejecting the catastrophic flood hypothesis by refining the chronology of the marine transgression and determining the water level of the early holocene black sea neoeuxinian lake is the aim of many ongoing black sea palaeoecological studies in this report we review previous studies and present new data on the early holocene marine transgression obtained from multidisciplinary studies of several cores from different parts of the black sea core 342 from the edge of the dniester paleovalley on nw shelf is particularly important because it provides wood and leaf material from several peat and muddy peat beds each up to 10 cm thick inter layered in a coastal succession with mud clay and shell coquina ams ages for wood fragments and sedge leaves in the peat layers provide critical new data for calibrating and re tuning of previously published shell and bulk detrital peat ages our multi disciplinary study of geological material recovered from different shelf areas of the black sea refines the chronology of the marine transgression and clarifies conflicting interpretations of the water level and salinity of the neoeuxinian lake prior to the initial mediterranean inflow imi and transgression of mediterranean water in the holocene we find that 1 the level of the late neoeuxinan lake prior to the early holocene mediterranean transgression stood around 40 m bsl but not 100 m or more as suggested by advocates of catastrophic rapid prominent flooding of the black sea by mediterranean water 2 at all times the neoeuxinan lake was brackish with salinity not less that 7 psu 3 by 8 9 ka bp the black sea shelf was already submerged by the mediterranean transgression an increase in salinity took place over 3600 years with rate of the marine water incursion being estimated in the order of 0 05 cm 1 7 cm a 1 4 the combined data set of sedimentological characteristics and microfossil data establish that the holocene marine transgression was of a gradual progressive nature in the early holocene

early oligocene dinoflagellate cysts from the upper rhine graben sw germany paleoenvironmental and paleoclimatic implications using principal component analysis and cyst diversity and equity trends we can recognize four distinct dinoflagellate cyst dinocyst assemblages from four rupelian early oligocene cores in the mainz embayment of the northern rhine graben sw germany these assemblages are the spiniferites ramosus pc1 thalassiphora pelagica pc2 homotryblium tenuispinosum pc3 and vozzhennikovia spinula pc4 assemblages the four cores provide an onshore offshore transect in the mainz embayment the h tenuispinosum assemblage shows high factor loadings in proximal to intermediate cores which is interpreted to reflect temporary high salinity conditions mean dinocyst diversity and equity increase with distance from the mid rupelian shoreline indicating increasingly stable paleoenvironmental conditions towards the center of the mainz embayment within individual cores changes in dinocyst assemblages through time are related to paleoenvironmental and paleoclimatological changes the three proximal to intermediate cores show dominance of the h tenuispinosum assemblage repeatedly alternating with high factor loadings of the t pelagica assemblage in both cases dinocyst diversity and equity tend to be reduced highest factor loadings of the s ramosus assemblage occur in intervals where neither of the above assemblages is dominant and tend to coincide with dinocyst diversity and equity maxima we interpret this distribution pattern to denote different paleoceanographic conditions reflecting drier and more humid phases in the early oligocene of central europe during relatively dry periods increased salinity conditions prevailed in proximal to intermediate settings of the mainz embayment as reflected by the dominance of the h tenuispinosum assemblage during more humid periods increased runoff led to higher nutrient availability and the formation of a pycnocline separating slightly less saline surface waters from higher saline deeper waters thus impeding vertical circulation these environmental conditions are documented in high loadings of the t pelagica assemblage which is indicative of increased eutrophication and or oxygen depleted bottom waters transitions between drier and more humid periods i e episodes of normal marine conditions are characterized by high loadings predominantly of the s ramosus assemblage as well as increased dinocyst diversity and equity values we propose that the alternations between drier and more humid phases may be related to variations in the ocean atmosphere moisture flux from the north atlantic into central europe bearing a high latitude climate signal 2002 elsevier science b v all rights reserved

the northern apennines palynological record as a contribute for the reconstruction of the messinian palaeoenvironments abstract the messinian stage has long been associated with an overall warm and dry climate whereas recent researches indicate either a warm and humid or a cool and dry climate the integrated stratigraphic record of vegetation and climatic changes from northern apennines sites provides the solution to this apparent contradiction its integration with the updated geological and sedimentological studies provides additional data for the reconstruction of the depositional palaeoenvironments in both marginal and deeper sub basins of the apennines foredeep the onset of the mediterranean salinity crisis msc is recorded in the gessoso solfifera of the vena del gesso marginal sub basin cyclical humid conditions corresponding to precession minima developed during the deposition of the shales interbedded with the gypsum 5 9 to 5 6 ma some cooler events took also place under the effects of global glacial stadials and regional factors apennines uplift at present no major changes from moist to dry conditions are attested to just before the salinity crisis as well as in sicily so climate did not play a major role in the onset of the msc despite the favourable context provided by inferred thermo xeric conditions in southern italy a drier episode indicated by the expansion of the open vegetation including the northward migration of lygeum postdates the onset of the salinity crisis of about 400 kyr in the lower post evaporitic deposits of maccarone deeper sub basin it falls within a period of global warming whereas at a regional scale it could correlate p p to the evaporite deposition in deeper basins and to hiatuses in the marginal basins of sicily and of the western sector of northern apennines its sudden end about 100 kyr later in coincidence with a significant increase of pinaceae indicates a turnover in the terrestrial setting not linked to major climate changes but possibly to a complex interaction between other palaeoenvironmental factors e g tectonics and eustatism in contrast organic walled dinoflagellate cysts exclude significant modifications in aquatic settings insaturation of either open marine or brackish conditions in the latter a later change is marked by the arrival of impagidinium sp 1 a species here referred instead to caspidinium rugosum about 7 m below the first colombaccio this occurrence together with the spread of pediastrum indicates a freshwater dilution i e the lago mare event during wetter climatic conditions on the adjacent landmass increase of tsuga and cedrus the successive arrival and or dominance of other paratethyan taxa such as i sp 2 i sp 3 and galeacysta etrusca indicate highly variable water environments marine vs continental water inputs during the deposition of the uppermost post evaporitic deposits the lago mare is stratigraphically sandwiched between an ash layer 130 m below dated at 5 5 ma and the beginning of the pliocene where a peak of impagidinium patulum marks the onset of open marine conditions the dominant humid subtropical to warm temperate climate indicates differences in both temperature and moisture values with respect to the coeval southern sections revealing climatic gradients within the mediterranean at least from the messinian no dramatic vegetation and climate changes have been recorded during the msc major changes occurred later as indicated by the palynological record from 2 6 ma this palynostratigraphic record is a good reference for more recent models of the development of the msc and for establishing time relationships between the apennine and sicilian successions

glacial hydrologic conditions in the black sea reconstructed using geochemical pore water profiles abstract chloride and 18 o compositions of interstitial water extracted from a long sediment core retrieved from the nw coast of the black sea allowed us to constrain the main hydrologic changes of the back sea during the late pleistocene and holocene prior to its reconnection with the mediterranean sea through the marmara sea at approximately 9000 calendar yr before present 9 ka cal bp the black sea has evolved as a fresh to brackish water lake at the time of reconnection hydrologic changes were drastic bottom water salinities changed from a few psu practical salinity unit to 22 psu since solutes in the interstitial water column within sediments are advected and diffused the measured concentrations do not reflect those of past bottom waters in order to reconstruct these former concentrations we used an advection diffusion model different scenarios of bottom water chloride and 18 o variations were accounted for in this model in order to simulate present day vertical profiles for concentrations of interstitial water in order to compare them to measured ones the comparison suggests that the glacial black sea was a homogeneous freshwater lake with a 18 o of 10 and a salinity of 1 psu modern hydrologic conditions would only have been reached at 2 ka cal bp concomitant with the onset of coccolith rich thin layers that characterize modern basin sediments such delayed salinization over 7000 yr in the basin may have been due to higher precipitation during the early holocene we also simulated the impact of a catastrophic reconnection and a smoother reconnection both salinity scenarios lead to undistinguishable modelled present day profiles indicating that the precise impact of the last reconnection was lost due to the advection diffusion processes

morphological and abundance variations in homotryblium cyst assemblages related to depositional environments uppermost oligocene lower miocene jylland denmark abstract abundant occurrences of homotryblium dinoflagellate cysts have been interpreted as reflecting deposition in near shore marginal marine areas either in hypersaline or low salinity environments it has also been suggested that the process length of homotryblium cysts is related to proximity to the coast the present study provides new insights in the ecology of homotryblium and adds important information about the use of the morphological variations of homotryblium cysts for environmental reconstructions it presents an example where homotryblium cysts show high relative abundances in a low salinity partly restricted marine depositional environment four different species of homotryblium were recorded homotryblium additense is proposed as a new species the regional palaeogeographic distribution of the four species h additense homotryblium vallum homotryblium plectilum and homotryblium tenuispinosum shows a distinct depositional proximal distal distribution pattern h additense occurs only in a narrow stratigraphic interval in the most proximal part of the study area h vallum only occurs sporadically mainly in the proximal parts of the study area h plectilum dominates the proximal areas while h tenuispinosum dominates the more distal areas variations in abundance and cyst type also seem to respond to systems tracts sequence boundaries and flooding surfaces the observed distributional patterns of homotryblium species strongly indicate a response to the salinity of the depositional environment it is further suggested that at least some of the recorded species of homotryblium originated from the same motile dinoflagellate species producing cysts of different morphology in response to variations in salinity a phenomenon known from extant dinoflagellates

vegetation and environmental dynamics in the southern black sea region since 18 kyr bp derived from the marine core 22 gc3 abstract sediments from the black sea a region historically dominated by forests and steppe landscapes are a valuable source of detailed information on the changes in regional terrestrial and aquatic environments at decadal to millennial scales here we present multi proxy environmental records pollen dinoflagellate cysts ca ti and oxygen isotope data from the uppermost 305 cm of the core 22 gc3 42 13 53 n 36 29 55 e collected from a water depth of 838 m in the southern part of the black sea in 2007 the records span the last 18 kyr all ages are given in cal kyr bp the pollen data reveal the dominance of the artemisia steppe in the region suggesting rather dry cold environments 18 14 5 kyr bp warming humidity increase during melt water pulses 16 1 14 5 kyr bp indicated by 18o records from the 22 gc3 core sediment and from the sofular cave stalagmite is expressed in more negative 13c values from the sofular cave usually interpreted as the spreading of c3 plants the records representing the interstadial complex 14 5 12 9 kyr bp show an increase in temperature and moisture indicated by forest development increased primary productivity and reduced surface run off whereas the switch from primary terrigenous to primary authigenic ca origin occurs 500 yr later the younger dryas cooling is clearly demonstrated by more negative 13c values from the sofular cave and a reduction of pines the early holocene 11 7 8 5 kyr bp interval reveals relatively dry conditions compared to the mostly moist and warm middle holocene 8 5 5 kyr bp which is characterized by the establishment of the species rich warm mixed and temperate deciduous forests in the low elevation belt temperate deciduous beech hornbeam forests in the middle and cool conifer forest in upper mountain belt the border between the early and middle holocene in the vegetation records coincides with the opening of the mediterranean corridor at 8 3 kyr bp as indicated by a marked change in the dinocyst assemblages and in the sediment lithology changes in the pollen assemblages indicate a reduction in forest cover after 5 kyr bp which was likely caused by increased anthropogenic pressure on the regional vegetation

atlas of modern dinoflagellate cyst distributions in the black sea corridor from aegean to aral seas including marmara black azov and caspian seas abstract we present the first comprehensive taxonomic and environmental study of dinoflagellate cysts in 185 surface sediment samples from the black sea corridor bsc which is a series of marine basins extending from the aegean to the aral seas including marmara black azov and caspian seas for decades these low salinity semi enclosed or endorheic basins have experienced large scale changes because of intensive agriculture and industrialisation with consequent eutrophication and increased algal blooms the bsc atlas data provide a baseline for improved understanding of linkages between surface water conditions and dinoflagellate cyst dinocyst distribution diversity and morphological variations by cross reference to dinocyst occurrences in sediment cores with radiocarbon ages covering the past c 11 700 years the history of recent biodiversity changes can be evaluated the seabed cyst samples integrate seasonal and multi year data which are not usually captured by plankton samples and the cyst composition can point to presence of previously unrecorded motile dinoflagellate species in the bsc results show the presence of at least 71 dinocyst taxa of which 36 can be related to motile stages recorded in the plankton comparison with sediment core records shows that five new taxa appear to have entered or re entered the region over the past century statistical analysis of the atlas data reveals the presence of four ecological assemblages which are primarily correlated with seasonal and annual surface water salinity and temperature correlation with phosphate nitrate and silicate nutrients chlorophyll a and bottom water oxygen is less clear but may be important for some taxa biodiversity indices reveal strong west east biogeographical differences among the basins that reflect the different histories of mediterranean versus ponto caspian connections the atlas data provide a standardised taxonomy and regional database for interpreting downcore cyst variations in terms of quantitative oceanographic changes the atlas also provides a baseline for monitoring further changes in the bsc dinocysts that may accompany the accelerating development of the region

compilation of geophysical geochronological and geochemical evidence indicates a rapid mediterranean derived submergence of the black sea s shelf and subsequent substantial salinification in the early holocene abstract our knowledge of rate and processes in which semi enclosed environments alternate from lacustrine to marine is commonly limited because of the paucity of specific proxies for sea level and salinity here we investigate the timing rate and key mechanisms involved in the transformation of the previously isolated black sea lake to the modern partly enclosed marine sea using a suite of geophysical geochemical and geochronological methods cores were collected in transects across shelves of ukraine romania bulgaria and turkey biogenic carbonate from these cores was analyzed for radiocarbon and strontium oxygen and carbon isotopes strontium results indicate that the submergence of the black sea shelf at 9300 calendar years bp was caused by the ingress of mediterranean water and was abrupt taking radiocarbon years are calibrated to calendar years by tuning the oxygen and carbon isotope composition of the mollusk record to that of the u th dated sofular cave stalagmites the match shows a reduction of the lake s prior high reservoir age accompanying the inflow of the mediterranean water in 900 years the salinity reached a threshold that excluded all previous black sea lacustrine fauna these results imply that any substantial postglacial submergence of the black sea shelves did not occur prior to entry of mediterranean water

constraining holocene sea surface conditions in the south western black sea using dinoflagellate cysts this paper presents two dinoflagellate cyst records from the south western shelf of the black sea a new site mar05 13 from the sakarya shelf is described and placed into context with site mar02 45 250 km distant on the thracian shelf the records provide a centennial resolution of surface water conditions in the holocene analysis of the data suggests that the surface salinity of the south western shelf increased in a gradual and progressive manner in the period 11 000 9000 cal a bp the assemblages suggest surface water salinities between 7 13 psu the initial arrival of euryhaline species 8100 cal a bp is linked to the reconnection of the black sea and marmara sea the suggested surface water changes related to the reconnection took approximately 1000 years following this initial change in assemblages a further increase in the number of euryhaline species is noted between 5000 and 4000 cal a bp this is linked to the establishment of more saline surface water conditions close to present day values the record for mar05 13 highlights the complexity of the changes in cyst assemblages during the mid holocene copyright 2012 john wiley sons ltd

river inflow and salinity changes in the caspian sea during the last 5500 years abstract pollen spores and dinoflagellate cysts have been analysed on three sediment cores 1 8 1 4 m long taken from the south and middle basins of the caspian sea a chronology available for one of the cores is based on calibrated radiocarbon dates ca 5 5 0 8 cal ka bp the pollen and spores assemblages indicate fluctuations between steppe and desert in addition there are some outstanding zones with a bias introduced by strong river inflow the dinocyst assemblages change between slightly brackish abundance of pyxidinopsis psilata and spiniferites cruciformis and more brackish dominance of impagidinium caspienense conditions during the second part of the holocene important flow modifications of the uzboy river and the volga river as well as salinity changes of the caspian sea causing sea level fluctuations have been reconstructed a major change is suggested at ca 4 cal ka bp with the end of a high level phase in the south basin amongst other hypotheses this could be caused by the end of a late and abundant flow of the uzboy river now defunct carrying to the caspian sea either meltwater from higher latitudes or water from the amu daria a similar later clear phase of water inflow has also been observed from 2 1 to 1 7 cal ka bp in the south basin and probably also in the north of the middle basin

first high resolution marinopalynological stratigraphy of late quaternary sediments from the central part of the bulgarian black sea area abstract spores pollen and dinoflagellate cysts of late pleistocene and holocene sediments were analyzed from giant gravity core 18 from the black sea continental slope recovered from a water depth of 971 m the investigated length of the core is 203 5 cm it includes 3 lithological units light grey clay sapropels and coccolith bearing ooze the core was sampled at 5 10 cm intervals sampling of the interval 141 5 126 cm was carried out at every cm ams radiocarbon dating of bulk organic carbon was performed on 18 selected sediment layers this chronological data allowed the first high resolution pollen stratigraphy of late quaternary sediments from the western black sea area to be presented the percentage spore pollen diagram is divided into 6 local pollen assemblage zones the trends in the vegetation dynamics and climate changes and the early history of migration of the majority of the arboreal taxa that nowadays occur in the eastern balkan range were traced out the palynological record suggests that open oak forests were spread in the eastern balkan range at the beginning of the holocene and shows early migration of the major temperate arboreal species such as quercus ulmus tilia and carpinus betulus this vegetation palaeosuccession continues with the spreading of mixed oak forests from 8950 until 2620 cal bp 8650 40 until 3120 35 14c bp followed by destructive changes due to human impact and climate deterioration a cooling of holocene climate that is well known in the north atlantic region as the 8200 yrs cold event is identified for the first time in marine records from the bulgarian black sea area the assemblages of dinoflagellate cysts and acritarchs were investigated to provide a reconstruction of surface seawater salinity and surface seawater temperature changes two main dinoflagellate cyst assemblages one dominated by fresh to brackish water species such as spiniferites cruciformis and pyxidinopsis psilata and a subsequent one that is characterized by euryhaline marine mediterranean species such as lingulodinium machaerophorum spiniferites belerius spiniferites bentorii operculodinium centrocarpum and acritarchs cymatiosphaera globulosa testified a change in sss from low salinity

the timing and evolution of the post glacial transgression across the sea of marmara shelf south of istanbul high resolution reflection seismic profiles with core analyses of sedimentary sequence near the sea of marmara som entrance to the strait of istanbul soi bosphorus provide detailed record of sealevel changes since the late glacial maximum lgm the sequence is deposited over the lgm erosional surface at a maximum depth of 105 m it includes seven seismic units that can be confidently correlated with 14c dated sedimentary units in the cores unit 6 represents levee deposits of the paleo soi channel that was deposited by a black sea outflow during 11 2 10 6 kyr bp the reflection surfaces at base of unit 5 and 4 correspond to wave cut terraces at 71and 63 m respectively and are estimated to be 10 6 and 9 8 kyr bp the seismic unit 2 overlaying a mud drape unit 3 comprises deltaic sediments that was deposited during 6 400 3200 yr 14c bp isopach map and

aspects of carbon isotope biogeochemistry of late quaternary sediments from the marmara sea and black sea abstract the marmara sea is situated between the world s largest permanently anoxic basin the black sea and an enclosed marginal sea the aegean sea which experienced quasi periodic sapropel deposition since miocene time it is connected to the black sea and the aegean sea through the straits of bosphorus and dardanelles respectively sapropel m1 which contains from 1 to 2 total organic carbon was deposited in the marmara sea between 6 and 10 5 ka we inferred the carbon isotopic composition of dissolved inorganic carbon dic in the water column of the marmara sea before during and after the deposition of sapropel m1 from the carbon isotopic composition of a planktonic foraminifera turborotalita quinqueloba and individual hexadecanoic and octadecanoic fatty acids the period of sapropel deposition is marked by a depletion of 13 c in the water column dic contrary to what may be expected if sapropel deposition represents a period of enhanced primary productivity instead we propose that both the relative 13 c depletion of dic during sapropel deposition and the absolute values we estimated 13 c 13 to 14 are consistent with enhancement of the relative contribution of 13 c depleted respired carbon to the water column dic pool such enhancement possibly resulted from density stratification that existed during sapropel m1 deposition the existence of density stratification is also argued from palynological and other lines of evidence other papers in this issue and is believed to have resulted from the encroachment of black sea water into the sea of marmara before 10 000 yr ago thus sapropel m1 appears to have formed during periods of enhanced runoff and preservation and not enhanced primary productivity

origin of late glacial holocene hemipelagic sediments in the aegean sea clay mineralogy and carbonate cementation abstract four hemipelagic lithological units are identified in the late glacial to holocene sediments in the aegean sea these lithologies are silty clay and clay in texture and include a varying mixture of loose terrigenous sediments supplied from the adjacent landmass gravel to sand sized cemented carbonate clasts and nodules sand to silt sized air born volcanic debris and biogenic remains sediment dispersal during the past 14 000 years was controlled mainly by the fluvial discharge rate by sea level variations which determined the proximity of basins to river mouths and by oceanographic conditions in the aegean sea cemented carbonate clasts and nodules occur in all sediments except unit c sapropel s1 they are well to friably cemented mottled to peloidal micrite or microcrystalline inter granular cement between terrigenous and bioclastic debris and the carbonate is 10 11 mole magnesium calcite during the deposition of sapropel s1 unit c the aegean sea was strongly stratified with colder more saline water masses occupying the deep basins which prevented the development of cemented carbonate nodules and clasts aragonite as pteropods and microcrystalline aragonite is present throughout the cores and together with the cemented carbonate clasts and nodules show that shallow pore waters in the aegean sea have been saturated to supersaturated with respect to both aragonite and magnesium calcite for at least the past 14 000 years results of xrd studies show that unit c sapropel s1 is characterized by lower smectite and kaolinite and higher illite and chlorite than the other units lower smectite illite and kaolinite chlorite ratios in unit c may reflect increased supply of illite and chlorite from european lowland rivers flowing into the black sea from rivers discharging directly into the northern and eastern aegean sea and decreased supply of kaolinite which is mainly of north african origin

pollen distribution in recent marine sediments eastern canada analysis of 90 samples from coastal and continental shelf areas off eastern canada between 42 and 69 n shows that quaternary pollen and spores are present in recent marine muds throughout this region pollen and spore concentrations range from 50 000 to 100 grains per cm3 and they decrease both offshore as a function of distance from vegetation sources and northwards as a function of lower vegetation density north of the summer arctic frontal zone isopercentage contours show that maximum relative abundances of most palynomorphs occur in marine sediments adjacent to their regions of highest vegetation representation onshore however pinus and picea pollen tend to increase in percentage abundance with distance offshore presence of these tree pollen in marine sediments off baffin island implies that wind transport is an important pathway by which bisaccate pollen types enter the ocean in addition to fluvial transport q mode factor analysis shows that four major factors account for 89 of the variance amo

marine dinocysts acritarchs and less well known npp tintinnids ostracod and foraminiferal linings copepod and worm remains

eemian and holocene sea surface conditions in the southern black sea organic walled dinoflagellate cyst record from core 22 gc3 in order to compare the sea surface conditions in the black sea during the holocene and eemian sapropelic parts of marine core 22 gc3 42 13 53 n 36 29 55 e 838 m water depth were studied for organic walled dinoflagellate cyst content the record shows a change from freshwater brackish assemblages pyxidinopsis psilata spiniferites cruciformis and caspidinium rugosum to more marine assemblages lingulodinium machaerophorum and spiniferites ramosus complex during each interglacial due to the inflow of saline mediterranean water the lacustrine marine transitions in 22 gc3 occurred at 8 3 cal kyr bp during the early holocene and 128 kyr bp during the early eemian slightly later compared to the onset of interglacial conditions on the adjacent land dinoflagellate cyst assemblages reveal higher sea surface salinity 28 30 e g spiniferites pachydermus bitectatodinium tepikiense and spiniferites mirabilis around 126 5 121 kyr bp in comparison to the holocene 15 20 as well as relatively high sea surface temperature e g tuberculodinium vancampoae s pachydermus and s mirabilis especially at 127 6 125 3 kyr bp establishment of high sea surface salinity during the eemian correlates very well with reconstructed relatively high global sea level and is explained as a combined effect of increased mediterranean supply and high temperatures at the beginning of the last interglacial the observed changes in the dinocyst record highlight the importance of nutrients for the composition of the eemian and holocene dinocyst assemblages

iunconsistencies in accumulation rates of black sea sediments inferred from records of laminae and 210pb recently published estimates for the age of the unit 1 unit 2 contact in black sea sediments based on accelerator mass spectrometry ams 14c measurements jones 1990 calvert et al 1991 appear to be older than those based on the previously published chronology based on lamina couplets degens et al 1980 hay 1988 by a factor of 2 to 3 to help reconcile the differences we compare sediment accumulation rates based on the 210pb method with estimates based on lamina counts for two cores from the black sea abyssal plain accumulation rates estimated using the 210pb technique have varied little over the last 150 years from the averages of 55 and 50 g m 2 yr 1 at stations in the western and eastern basins respectively these values are about a factor of 2 lower than accumulation rates derived by counting lamina couplets over the dated intervals close examination of the laminae suggests that the discrepancy exists both because it is difficult to count the very fine laminae and because a complete couplet is not deposited every year in order to provide a useful stratigraphic horizon for future investigators studying sedimentary records of the black sea we estimate the age of a distinct black marker horizon which can be easily identified across the entire abyssal plain to be 150 8 years deposited in 1838 8 a d

natural and anthropogenic rapid changes in the kara bogaz gol over the last two centuries reconstructed from palynological analyses and a comparison to instrumental records abstract palynological analyses pollen and dinocysts of a sediment core taken in the kara bogaz gol have been used to reconstruct rapid and catastrophic environmental changes over the last two centuries chronology based on 210pb a natural cyclicity 65 years of water level changes in the caspian sea cs and in the kara bogaz gol kbg and anthropogenic factors building of a dam separating the cs and the kbg waters combine to induce rapid changes in water levels of the kbg in the salinity of its waters and in vegetation cover of its surroundings the impact of low water levels on the dinocysts is marked by a lower diversity and the survival of two species that are typical of the kbg the caspian sea species present in the kbg having disappeared during periods of higher water levels ad 1871 1878 the lake is surrounded by a steppe like vegetation dominated by artemisia whereas during periods of low water levels ad 1878 1913 and ad 1955 1998 the emerged shore are colonised by chenopodiaceae the period of ad 1913 1955 corresponding to decreasing water levels has an extremely low pollen concentration and a maximum of reworking of arboreal taxa during the last low level period humans responded by abandoning the shores of the bay what happened to the kbg can be used as an example of what may happen in the future for the aral sea a problem of reworking of tertiary dinocysts into modern deposits has been detected owing to the knowledge of the modern dinoflagellate assemblages recently made available through a water survey a comparison to modern surface pollen samples from central asia anzali caspian sea south and central basins aral sea lake balkhash lake issyk kul and the chinese tien shan range allows us to establish the potential reworking of at least five arboreal pollen taxa possibly by run off and dust storms

palynology and micropalaeontology of the pliocene pleistocene transition in outcrop from the western caspian sea azerbaijan potential links with the mediterranean black sea and the arctic ocean abstract new palynological ostracod and foraminiferal data are presented from a long outcrop section in the jeirankechmez river valley azerbaijan near the western coast of the caspian sea the interval studied includes the upper part of the pliocene productive series and overlying plio pleistocene akchagylian akchagyl and apsheronian apsheron regional stages productive series sediments were deposited in a closed fluvio lacustrine basin isolated from any marine influence the onset of akchagyl deposition is marked by a lithological change associated with a significant flooding event that at its maximum extent reached the sea of azov and into present day iran kazakhstan turkmenistan and russia at the jeirankechmez locality the lowermost beds of the akchagyl contain predominantly freshwater assemblages with very minimal marine or brackish content showing that the onset of akchagyl deposition was not a marine induced event reworked mesozoic palynomorphs occur frequently in this lowermost interval including the reworked pollen taxa aquilapollenites triprojectus that were eroded from the north or north east significant marine influence is evident ca 30 m above the base of the akchagyl in the studied outcrop marked by the cassidulina beds which contain a distinct but low diversity assemblage of foraminifera that occurs widely and can be correlated in many parts of the greater caspian region dinoflagellate cysts dinocysts in the marine interval include frequent specimens very similar to algidasphaeridium capillatum matsuoka and bujak a species only previously recorded from the northern bering sea the combined evidence from these dinocysts and foraminifera suggests that a marine i e seaway connection existed briefly between the arctic ocean and the caspian sea at the very end of the pliocene re examination of core material from the adriatic sea shows that cassidulina reniforme norvang was present in the mediterranean during and shortly after the last glacial maximum the possibility that the end pliocene marine incursion came from the mediterranean via the black sea region to the caspian sea cannot be entirely ruled out but is considered unlikely biometric analyses are applied to obtain a better understanding of the palaeoenvironmental significance of the assemblages dominated by cassidulinids an interval 300 m thick is assigned to the apsheron regional stage on the basis of predominantly brackish ostracod and dinocyst associations the dinocysts are of peri paratethyan affinity and closely resemble species first described from miocene and pliocene sediments in the pannonian and dacic basins of eastern europe many similarities exist in the microplankton records dinocysts and acritarchs between the caspian sea the black sea and central paratethys

pollen plant macrofossil and charcoal records for palaeovegetation reconstruction in the mediterranean black sea corridor since the last glacial maximum new reconstructions of changing vegetation patterns in the mediterranean black sea corridor since the last glacial maximum are being produced by an improved biomisation scheme that uses both pollen and plant macrofossil data in conjunction changes in fire regimes over the same interval will also be reconstructed using both microscopic and macroscopic charcoal remains these reconstructions will allow a diagnosis of the interactions between climate fire and vegetation on millennial timescales and will also help to clarify the role of coastline and other geomorphic changes salinity and impacts of human activities in this region these new data sets are being produced as a result of collaboration between the palynology working group wg 2 within the igcp 521 project and the international palaeovegetation mapping project biome 6000 the main objective of this paper is to present the goals of this cooperation methodology including limitations and planned improvements and to show the initial results of some applications

late quaternary dinoflagellate cysts from the black marmara and aegean seas variations in assemblages morphology and paleosalinity abstract the link between sea surface salinity sss and dinoflagellate cyst morphology was studied quantitatively in cores of late quaternary mud from the black marmara and aegean seas where oxygen isotopic and planktonic foraminiferal data show salinities of about 5 19 15 22 and 36 39 ppt respectively in the black sea late glacial muds contain low diversity assemblages of the cruciform species spiniferites cruciformis and pyxidinopsis psilata with most s cruciformis cysts having expanded septal membranes form 1 circular outline form 2 irregular the assemblage is associated with surface salinities of in the northeast aegean core stenohaline species and morphotypes are rare occurring only as low percentages of s cruciformis forms 3 and 4 and o centrocarpum var truncatum in a mid holocene sapropel that was deposited during a period of high runoff and black sea water outflow marmara sea cores record surface salinities of 14 18 ppt during late glacial sapropel deposition and 20 22 ppt for the overlying marine sediments the sapropel is dominated by s cruciformis forms 1 and 2 and by p psilata with common l machaerophorum clavate and normal forms in surface sediments l machaerophorum is co dominant with o centrocarpum normal and truncate forms brigantedinium and spiniferites spp percentages of s cruciformis five forms and l machaerophorum two forms plotted against proxy salinity data however show no clear correlation indicating that morphological variation is not a simple function of salinity

late quaternary environmental changes and latitudinal shifts of the antarctic circumpolar current as recorded by dinoflagellate cysts from offshore chile 41 s abstract the late quaternary organic walled dinoflagellate cyst record of site 1233 41 s offshore chile was studied with a 200 year resolution spanning the last 25 000 years the study provides the first continuous record of sub recent and recent dinoflagellate cysts in the southeast se pacific major changes in the composition of the cyst association cyst concentration and morphology of operculodinium centrocarpum reflect changes in sea surface temperature sst sea surface salinity sss palaeoproductivity and upwelling intensity these changes can be associated with latitudinal shifts of the circumpolar frontal systems the high cyst concentration high brigantedinium spp abundances low species diversity and the occurrence of certain cold water species are supportive for a 7 10 equatorward shift of the antarctic circumpolar current acc during the coldest phase of the last glacial maximum lgm between 25 and 21 1 cal ka bp deglacial warming initiated at 18 6 cal ka bp termination i 18 6 11 1 cal ka bp is interrupted by an unstable period of extreme seasonality rather than a cooling event between 14 4 and 13 2 cal ka bp synchronous with the antarctic cold reversal acr the holocene maximum is observed between 11 6 and 9 8 cal ka bp and is typified by the most southward position of the northern margin of the acc a cooling phase occurred during the early holocene until 7 cal ka bp and during the last 0 8 ka our data indicates that the se pacific 41 s climate has been influenced over the whole record by changes in the southern hemisphere sh high latitudes while during the mid to late holocene also a tropical forcing mechanism was involved including the el nino southern oscillation and the variable hadley cell intensity furthermore this study showed a relationship between the variable morphology of the spines processes of o centrocarpum and the combined variation of sea surface salinity and temperature sss sst ratio

paleoenvironmental changes on the northeastern and southwestern black sea shelves during the holocene abstract four paleoceanographic events are distinguished during the holocene based on changes in macro and microfossil assemblages studied from three sediment cores ak 521 522 2571 from the outer northeast shelf and from core mar02 45 situated on the southwest shelf of the black sea west to the bosphorus the lithology and fossils were previously studied from cores ak 521 and ak 522 and mar02 45 however high resolution ostracod analyses from the ams 14 c dated core ak 2571 allowed for a revision of the taxonomy and paleoecological interpretation of this microfaunal group on the ne shelf downcore changes in the relative abundance of the polyhaline ostracods are found to be contemporaneous in all three cores from the ne shelf as a result centennial millennial scale fluctuations of the bottom water salinity are resolved in the area a broader scale examination of paleoenvironmental changes between the ne and sw shelves is also made and the surface to bottom salinity gradient is discussed an uncalibrated radiocarbon based chronology is used throughout this paper to facilitate comparison with the regional chronostratigraphy of marine transgression and regressions in the black sea the calibrated ages corrected for the changes in reservoir age through the holocene are also provided the first paleoceanographic event is associated with the pulse of mediterranean water previously established at about 9 8 9 3 ka bp this event is clearly observed in the sw region but not on the ne shelf due to a hiatus in the longest core ak 521 the second event is represented on both the ne and sw shelves as a replacement of brackish benthic fauna and surface phytoplankton with marine ones between 8 4 and 6 9 ka bp indicating a gradual increase in salinity the third event is marked by opposing trends in surface and bottom water salinity changes on the ne shelf bottom water salinity rose to modern values by 6 5 ka bp and then decreased within the interval 6 4 5 3 ka bp as recorded by the ostracod assemblages on the sw shelf surface water salinity reached modern values by 5 6 ka bp and remained constant until present day as inferred from the dinoflagellate cyst assemblages the fourth event is marked by a recurring increase in bottom water salinity to modern values indicated by the polyhaline ostracod assemblages at 5 3 ka bp in the ne region after which only minor salinity fluctuations are observed

dinoflagellate cysts freshwater algae and fungal spores as salinity indicators in late quaternary cores from marmara and black seas abstract seismic profiles and mollusks have been used to suggest that from 12 500 to 7000 yr bp the black sea was an isolated freshwater lake containing potable water and implying a surface salinity of 24 and that spiniferites cruciformis spiniferites inaequalis peridinium ponticum polykrikos spp and quinquecuspis concreta characterize the lower salinity of the marmara and or black seas the core top data and correlatable down core assemblage changes in time equivalent sapropelic and brown muds show that there is no evidence for differential aerobic decay of dinocysts in the study area the main acritarchs are sigmopollis psilatum concentricystes cf c rubinus and cf acritarch 8 of traverse 1978 all of which are absent from the aegean sea and decrease in abundance with increasing salinity the first two taxa have been reported previously as freshwater species fungal remains show a similar distribution pattern to the freshwater acritarchs indicating their origin from terrestrial environments freshwater chlorococcales are almost confined to the black sea but they have rare occurrences in the aegean indicating long distance transport microforaminiferal linings are abundant in the marmara sea but are absent in deep water of the black sea in the marmara sea mid late holocene assemblages

palynological evidence for climatic change anthropogenic activity and outflow of black sea water during the late pleistocene and holocene centennial to decadal scale records from the black and marmara seas abstract previous marine palynology studies of pollen and dinoflagellate cysts dinocysts in the black sea mediterranean corridor were made on short cores allowing only millennial century scale reconstruction of past climates we now describe pollen accumulation rates for 5 cores with eleven 14c ages over 30 000 years and new decadal scale data for a holocene core with fourteen 14c ages pollen influxes show pinus abies quercus forest steppe and deteriorating climate from 29 8 24 kyr bp then colder drier pre and post lgm conditions with artemisia cheno ams and ephedra that lasted through the bolling interstade deciduous oak returns by the younger dryas and rapidly expands followed by pistacia by 9 3 kyr bp foraminiferal 18o shows 4 c cooler than present late glacial summers and rapid holocene warming by 9 bp influxes from quercus cerris tilia fagus castanea ulmus shade ferns aquatics swamp plants and 18o indicate warm winters 5 c or more and year round precipitation 600 1000 mm not the dry conditions that would be required for black sea drawdown there is mid holocene expansion of carpinus evergreen quercus and pistacia walnut olive and cereal pollen suggest early cultivation attempts but no sustained farming before 4 5 kyr bp dinocyst assemblages show major changes traceable throughout the corridor variability in process length marks low diversity n 13 pleniglacial early holocene spiniferites cruciformis assemblages suggesting fluctuating salinity like the modern caspian sea with brackish to saline conditions 5 16 distributions of euryhaline cysts spiniferites mirabilis and spiniferites bentorii show the aegean and marmara seas were connected by 11 kyr bp and linked to black sea by 9 3 kyr bp there is no palynological evidence of either freshwater salinity

the holocene history of the ne black sea and surrounding areas an integrated record of marine and terrestrial palaeoenvironmental change here we present an almost complete and integrated holocene record of marine and terrestrial palaeoenvironmental change from the ne shelf of the black sea a dinoflagellate cyst record used to recon

oscillating quaternary water levels of the marmara sea and vigorous outflow into the aegean sea from the marmara sea black sea drainage corridor abstract detailed interpretation of single channel air gun and deep tow boomer profiles demonstrates that the marmara sea turkey experienced small amplitude 70 m fluctuations in sea level during the later quaternary limited in magnitude by the sill depth of the strait of dardanelles moderate subsidence along the southern shelf and quaternary glacio eustatic sea level variations created several stacked deltaic successions separated by major shelf crossing unconformities which developed during the transitions from global glacial to interglacial periods near the strait of dardanelles a series of sand prone deposits are identified beneath an uppermost holocene transparent mud drape the sandy deposits thicken into mounds with the morphology and cross sectional geometries of barrier islands sand waves and current generated marine bars all cross stratification indicates unidirectional flow towards the dardanelles prior to the deposition of the transparent drape which began 7000 years bp in strong support of the notion that the marmara sea flowed westwards into the aegean sea through the dardanelles at times of deglaciation in northern europe the global sea level curve shows that at 11 000 and 9500 years bp sea level rose to the sill depths of the straits of dardanelles and bosphorus respectively the effect from 11 000 to 9500 years bp was seawater incursion into the marmara sea drowning and formation of algal serpulid bioherms atop lowstand barrier islands and transgression of shelves and lowstand deltas at 9500 years bp glacial meltwater temporarily stored in the black sea lake developed into a vigorous southward flow toward the aegean sea forming west directed sandy bedforms in the western marmara sea and initiating deposition of sapropel s1 in the aegean sea this strong outflow persisted until 7000 years bp after which a mud drape began to accumulate in the marmara sea and euryhaline mediterranean mollusks successfully migrated into a progressively more saline black sea where sapropel deposition began most eastern mediterranean sapropels from s1 to s11 appear to correlate with periods of rising sea level and breaching or near breaching of the bosphorus sill these events are believed to coincide with times of vigorous outflow of low salinity fresh surface waters transiting the black sea marmara sea corridor and ultimately derived from melting of northern european ice sheets

paleoclimatic and paleoceanographic conditions leading to development of sapropel layer s1 in the aegean sea abstract sapropel s1 occurs as 25 35 cm thick black weakly laminated muds in aegean sea cores s1 was deposited between 9600 and 6400 yr b p during a period of isotopically depleted and relatively cool surface waters micro faunal and floral data indicate a major reduction in surface waters salinity during the deposition of s1 and oxygen isotopic data show a northerly fresh water source relatively light 13 c org and high pollen spore concentrations in s1 suggest increased influx of terrestrial organic carbon probably supplied by major rivers draining into the northern aegean sea benthic foraminifera indicate high nutrient low oxygen bottom waters for s1 and together with silt sized hematite and manganese coatings suggest that during the deposition of s1 surface sediments were oxic visual and xrd evidence of pyrite in s1 together with enrichments in s cu zn as ni cr and fe suggest that subsurface conditions were sufficiently reducing for so 4 2 reduction to occur probably by diffusion from surface oxic into subsurface anoxic sediments palynomorphs in s1 show large increases in terrestrial pollen and spores with the floral assemblage indicating significant influx from northern european rivers and minor african components associated with increased summer monsoonal rain abundance of dinoflagellates and amorphogen suggests some increase in primary productivity in response to increased influx of humic compounds however there is no evidence of upwelling the clay fraction in s1 shows notable decreases in smectite and kaolinite and reciprocal increases in illite and chlorite the combined data suggested that the evolution of s1 in the aegean sea largely resulted from stagnation of the surface waters during the final disintegration of the continental ice sheets rather than an increase in primary productivity and higher preservation of organic carbon on the sea floor

last glacial holocene paleoceanography of the black sea and marmara sea stable isotopic foraminiferal and coccolith evidence multi proxy data and radiocarbon dates from several key cores from the black sea and marmara sea document a complex paleoceanographic history for the last v30 000 yr the marmara sea was isolated from both the black sea and the aegean sea during glacial periods when global sea level lowering subaerially exposed the shallow sills at the straits of bosphorus and dardanelles i e lake stage and reconnected through both straits during interglacial periods when rise of global sea level breached the shallow sills i e gateway stage micropaleontological data show that during the lake stage the surface water masses in both the marmara sea and black sea became notably brackish however during the gateway stages there was a low salinity surface layer and normal marine water mass beneath two sapropel layers are identified in the marmara sea cores sapropels m2 and m1 were deposited between v29 5 and 23 5 ka and v10 5 and 6 0 ka respectively micropaleontological and stable isotopic data show that the surface water salinities were reduced considerably during the deposition of both sapropel layers m2 and m1 and calculation using planktonic foraminiferal transfer functions shows that sea surface temperatures were notably lower during these intervals the presence of fauna and flora with black sea affinities and the absence of mediterranean fauna and flora in sapropels m1 and m2 strongly suggest that communication existed with the black sea during these times a benthic foraminiferal oxygen index shows that the onset of suboxic conditions in the marmara sea rapidly followed the establishment of fully marine conditions at v11 10 5 ka and are attributed to black sea outflow into the marmara sea since 10 5 ka these suboxic conditions have persisted to the present the data discussed in this paper are completely at odds with the flood hypothesis of ryan et al 1997 and ryan and pitman 1999 crown copyright 2002 elsevier science b v all rights reserved

contribution palynostratigraphique dinokystes pollen et spores a la connaissance de la mer de champlain coupe de saint cesaire quebec high resolution continental pollen and spores and marine dinoflagellate cysts microfloral records were obtained from a section consisting of about 0 5 m of glaciolacustrine and 2 5 m of champlain sea deposits at the saint cesaire site the pollen and spore assemblages indicate the existence of a regional open vegetation of shrub tundra to forest tundra fluctuations in the percentages of picea and shrub and herb taxa are related to regional afforestation and paleogeographical evolution of the basin the champlain sea sediments contain an abundant dinocyst flora dominated by operculodinium centrocarpum brigantedinium spp and algidasphaeridium minutum which indicate cold arctic conditions in surface waters fluctuations in concentration 102 104 cm 3 and relative abundance of dinocyst species are attributed to changes in dinoflagellate productivity and paleoceanographic conditions notably paleosalinity morphological variations of operculodinium centrocarpum and algidasphaeridium minutum led to

average process length variation of the marine dinoflagellate cyst operculodinium centrocarpum in the tropical and southern hemisphere oceans assessing its potential as a palaeosalinity proxy the study investigates the morphological variability of the dinoflagellate cyst operculodinium centrocarpum resting cyst of protoceratium reticulatum in core top samples distributed over the southern hemisphere and the tropics in relation to sea surface temperature sst and sea surface salinity sss at the corresponding sites the process lengths show a moderate inverse relationship to summer sst ssst r 0 44 and ssss ssst r 0 4 however lateral transport of cysts probably produced noise in the plots after excluding tropical and southern hemisphere sites considered to have been affected by long distance lateral transport the relationship between process length and density follows the equation sd 0 8422x 1016 9 r 0 55 with a root mean square error 0 63 kg m 3 while the negative correlation with ssst increases up to r 0 79 next to salinity this study thus highlights the importance of a second factor temperature affecting process length in the topics and the southern hemisphere oceans

marine connections of amazonia evidence from foraminifera and dinoflagellate cysts early to middle miocene colombia peru abstract species composition in the present day amazonian heartland has an imprint of past marine influence the exact nature timing and extent of this marine influence however are largely unresolved here we use calcareous tests of foraminifera and marine palynomorphs from miocene sediments in northwestern amazonia to extend on current estimates for salinity ranges paleoenvironments and paleogeography our samples mostly contain tests and or organic linings of euryhaline tolerant to a wide range of salinity foraminifera of the genera ammonia trochammina and elphidium with ammonia being by far the dominant genus at all locations organic walled dinoflagellate cysts dinocysts such as spiniferites brigantedinium and tuberculodinium vancampoae are also common at a number of sites this association of foraminifera and dinocyst taxa points at varying salinities with aberrant forms of ammonia indicating lower limits of 0 10 psu practical salinity units whereas dinocyst associations suggest more marine conditions such regional heterogeneity is common at the interface of shallow marine to freshwater environments like estuaries we conclude that during the early and middle miocene marginal marine conditions reached at least 2000 km inland from the caribbean portal global high sea level and fast subsidence in the sub andean zone are thought to be the controlling mechanisms of the marine incursions lowering of global sea level and a change in tectonic regime terminated the incursions in the course of the plio pleistocene

brine volcanism and the interior structures of asteroids and icy satellites abstract cryovolcanism is among the foremost processes responsible for modifying the surfaces of icy satellites volcanic brine petrogenesis in ammonia deficient satellites should mainly involve eutectic melting in relevant salt water systems carbonaceous chondrites provide useful insights into the compositions of salts and aqueously altered rock in icy satellites and asteroids c1 chondrites contain about one fifth by mass of salts in various states of hydration many aspects of the petrogenesis and physical volcanology of icy satellite brines should be well described in the system h2o mgso4 na2so4 minor components include sulfates of k ni mn and ca chondrites also contain abundant carbonates but these are probably not very important in brine magmatism due to their low solubilities under expected conditions chlorides are also unimportant under most circumstances because of the low cosmic abundance ratio of cl s soluble salts may have profound effects on the geology and structure of icy satellites and asteroids in some models late episodes of water volcanism are facilitated by high buoyant forces due to the relatively high densities of sulfate rich mantle and crustal layers in other models early hypersaline brine volcanism quickly yields to plutonic magmatism due to low crustal densities europa probably has a layered crust composed of anhydrous mg na sulfates near the base and a frozen or partially molten eutectic mixture of ice and hydrated mg and na sulfates near the surface ganymede may have a crust about 300 km thick composed of a 10 1 ratio of ice mirabilite and a mantle 500 km thick composed of 50 ice phases plus 50 hydrated mg and na sulfates

the weichselian late glacial in southwestern europe iberian peninsula pyrenees massif central northern apennines this paper presents a summary of late glacial environmental changes in southwestern europe lberian peninsula pyrenees massif central and the northern apennines the emphasis is on palaeoclimatic interpretations inferred from key sites in the region from which the most detailed records are available and which have been radiocarbon dated the earliest evidence for climatic improvement following the end of the last glacial stage is dated to ca 15 ka bp and is found at a few sites only by 13 ka bp a more widespread and marked climatic improvement is evident although it is difficult to be precise in the timing and magnitude of the event there are significant variations in detail between the late glacial records but evidence for a significant cooling correlated with the younger dryas event is widespread throughout the region just two sites in the region provide evidence for an earlier less emphatic phase of climatic cooling which is tentatively equated with the older dryas of continental northern europe dry conditions appear to have predominated throughout the region in the later part of the younger dryas and the early holocene

late glacial holocene paleoclimatic and paleoceanographic evolution of the aegean sea micropaleontological and stable isotopic evidence abstract late glacial to holocene paleoclimatic and paleoceanographic changes are examined using records of calcareous and organic walled marine microfossils pollen and terrestrial spores and oxygen isotope data in cores from the aegean sea basins planktic foraminiferal coccolith and dinoflagellate data show that the late glacial holocene transition in the region was associated with a large warming of surface water mediterranean based paleotransfer functions for planktic foraminifera show a 5 10 c increase in surface water temperature from 14 000 to 9600 yr b p estimates of surface water oxygen isotopic composition 18 o w derived from planktic foraminiferal oxygen isotopic and transfer function data indicate that this warming was associated with a 2 0 to 2 5 reduction in 18 o w transfer function results indicate corresponding 1 0 to 1 5 salinity reductions for this tim ca 6400 9600 yr b p throughout the aegean sea pollen dinoflagellate and isotopic data show that the early holocene excess fresh water originated from rapid melting of the northern european and siberian ice sheets supplied primarily from the black sea by the opening of bosphorus and dardanelles channels during the post glacial sea level rise and supplemented by major rivers entering the aegean sea continuous outflow of fresh water into the aegean sea provided a low salinity surface lid preventing the ventilation of the deep water benthic foraminifera shows a major turn over that indicates low dissolved oxygen however bottom waters were not anoxic sapropel level s1 resulted from a combination of stagnant deep water in isolated depressions increased terrigenous organic matter and periods of high primary productivity as indicated by pollen and dinocysts respectively the surface water temperature and salinity reached present day values at 6400 yr b p with little subsequent change despite the major deforestation onshore