history and influence of the danube delta lobes on the evolution of the ancient harbour of orgame dobrogea romania on the coast of northern dobrogea south of the danube delta the greek settlement of orgame was founded in the mid 7th c bc probably by milesian colonists the ancient city was located on the cape dolojman which today overlooks a large lagoon complex we undertook a chronostratigraphic study to i understand coastal changes around cape dolojman since ca 5000 years bp in connection with the construction of the danube delta lobes and ii identify potential sediment impacts related to human occupation of the site three cores were extracted from the lagoon area sedimentological and biological analyses were undertaken to reconstruct the evolution of the coastal palaeoenvironments the results show a closure of the marine bay around 3500 cal bp and its transformation into a lagoon environment the first major environmental change was due to the construction of the lobe st george i and the formation of the barrier lupilor around 2000 cal bp the formation of an intra lagoonal lobe the dunavatz led to the gradual transformation of the lagoon into a fluvial dominated system paradoxically lagoon waters today still wash the ancient greek harbour environment which has not been totally infilled by alluvial sediments to understand this paradox in a context of coastal progradation we compared and contrasted the geomorphological data with the nearby city of istros histria which was already landlocked at this time the location of these two greek colonies relative to the coastal sediment cell and barriers partly explains their contrasting palaeoenvironmental evolution until 2650 cal bp the increase in charcoal and organic matter in sedimentary archives is interpreted as an anthropogenic signal for a more extensive use of the vegetation cover following the foundation of the city of orgame e g for domestic use and funeral rites

intensified aridity in the qaidam basin during the middle miocene constraints from ostracod stable isotope and weathering records the thick and continuous cenozoic successions in the qaidam basin provide an excellent paleoclimate archive here we focus on the ostracod fauna stable isotope records and paleoweathering indice

the use of jadammina macrescens brady and balticammina pseudomacrescens bronnimann lutze and whittaker protozoa foraminiferida as sea level indicators in studies of foraminiferal distributions in saltmarshes in new england and atlantic canada balticammina pseudomacrescens and jadammina macrescens have formerly been grouped as trochammina macrescens this study recognises them as distinct species and shows that they have significantly different distributions on the surface of saltmarshes in maine here relative abundances of j macrescens correlate with tidal elevation r2 0 55 p 0 00 whereas those of b pseudomacrescens do not r2 0 03 p 0 34 therefore j macrescens is a better sea level indicator in maine marshes than b pseudomacrescens in menunketesuck river marsh connecticut a clear vertical zonation of saltmarsh foraminifera is absent which hinders interpretation of fossil data this study shows that in maine separating b pseudomacrescens and j macrescens in counts of fossil data facilitates the detection of transgressional and regressional events in the biostratigraphical record and hence the reconstruction of local sea level histories regional variability between northern and southern new england saltmarshes necessitates the establishment of local reference sets of modern analogue data to aid palaeoecological interpretations

palaeo water depth estimation for a 600 year record from nam co tibet using an ostracod based transfer function a modern training set of ostracods from the large slightly saline lake nam co on the southeastern tibetan plateau is presented in total 44 samples covering the largest part of the lake and water depth from 2 to 93 m were taken there are eight ostracod species in surface sediments of nam co leucocytherella sinensis leucocythere dorsotuberosa fabaeformiscandona gyirongensis candona xizangensis candona candida ilyocypris cf mongolica eucypris gyirongensis and limnocythere inopinata in order of mean dominance a morphological variant of l dorsotuberosa the forma postilirata is an indicator form of deep water below the thermocline the 36 samples comprise a sufficient number of ostracods for analysis covering water depths between 3 7 and 89 3 m two transfer function models based on weighted average binomial regression wa br and weighted average partial least square regression wa pls using the programs excel and c2 were established to estimate past water depths of nam co transfer functions were applied to ostracod data from two short cores from nam co covering approximately the past 600 years model results show a lake level minimum occurring during the little ice age lia between about 1490 and 1760 ad this minimum corresponds to results from previous stable isotope analysis and indicates a lake level which was about 5 m below the present day level the more exact transfer function model wa pls was set up using c2 and revealed a higher correlation index r o f 0 91 and a lower standard error of 6 7 m however the more selective because of using indicator taxa only wa br model using excel r 0 88 standard error 10 6 m seems to represent palaeo water depths better at least for the studied short cores

late quaternary marine mollusca as palaeoenvironmental proxies a compilation and assessment of basic numerical data for ne atlantic species found in shallow water abstract temperature salinity and depth limits are given for selected molluscs from boreal and arctic regions of the ne atlantic and adjacent shelf seas the significance of the data for palaeoenviromental analysis is briefly discussed

variable noding and palaeoecology of a middle jurassic limnocytherid ostracod implications for modern brackish water taxa abstract no less than seven junior synonyms exist of theriosynoecum kirtlingtonense bate 1965 this taxonomic confusion has been brought about by variations in the degree and patterns of noding within a single species which was widespread both geographically from the south of england to the hebrides and in the palaeoenvironments it occupied from freshwater to polyhaline a critical analysis is undertaken of the taxonomy of theriosynoecum kirtlingtonense within a framework of palaeoenvironmental constraint using only those bio characters which are invariable at the intraspecific level the distribution of the species in a section of the upper bathonian forest marble formation at tarlton in gloucestershire is investigated the population age structure was used to determine those levels in which the species occurs as an autochthonous component and its variable noding investigated with respect to salinity variations all aspects of noding in this limnocytherid and in the neogene to recent brackish water species cyprideis torosa jones 1850 are compared and contrasted and both are shown to be related fundamentally to salinity

ostracods from a marmara sea lagoon turkey as tsunami indicators abstract a 352 cm long sediment core from hersek lagoon gulf of izmit was investigated for its ostracod species composition in order to evaluate the potential of ostracods to detect tsunami deposits in coastal environments the gulf of izmit is the eastern bay of the marmara sea which is tectonically controlled by the north anatolian fault ostracod shells are rare in the lower third of the core which probably represents a coastal wetland environment according to radiocarbon dating of terrestrial plant remains this unit was deposited between ad 500 and ad 800 above ostracod shells are abundant and dominantly monospecific composed almost exclusively of the widespread brackish water ostracod cyprideis torosa this almost monospecific occurrence indicates the establishment and maintenance of the hersek lagoon after ad 800 three distinct layers of mollusc shells and fragments contain ostracod shells of marine and to a lesser extent non marine origin in addition to those of c torosa the shell layers are further characterized by significant maxima in total ostracod shell numbers the high concentration of ostracod shells the higher species numbers and the mixture of marine lagoonal and non marine ostracod shells shows that shell layers were formed as high energy deposits resulting from tsunamis or large storms in the marmara sea the partial occurrence of non marine ostracod shells in the shell layers possibly indicates that tsunamis with extensive run ups and significant backwash flows caused the high energy deposits rather than large storms the investigated sediments show that lagoonal ostracods can serve as good proxies for tsunamis or large storms through significant variations in total shell numbers species numbers and the mixing of shells of different origin

geoarchaeology confirms location of the ancient harbour basin of ostia italy abstract to the northwest of the ancient city of ostia the analysis of cores revealed a stratigraphic sequence which we interpret as the filling of a harbour basin this basin located at the west of the so called palazzo imperiale presents seven characteristics 1 the maximum depth is 6 m below the roman sea level this depth allowed any type of ship even heavy tonnage to access the harbour 2 a chronostratigraphic gap at 6 m below roman sea level suggests digging operations in the basin or subsequent dredging that have caused the loss of sedimentary archives 3 the filling consists of dark clays typical of a quiet environment but open to marine and river influences 4 the dates at the base of this sequence give a range between the 4th and the 2nd century bc 5 in the harbour sequence a facies change at 2 5 m under the roman sea level involves a change in the processes of sedimentation and or operation 6 no later than the beginning of the 1st century ad the thickness of the water column in the basin is less than 50 cm and seems to be caused by a massive siltation following a succession of floods of the tiber 7 this basin was thus already abandoned during the start up of portus

strontium isotope variations in single ostracod valves from the gulf of carpentaria australia a palaeoenvironmental indicator the gulf of carpentaria is a shallow 70 m epicontinental sea which was partially and at times fully isolated from the ocean due to changing sea levels in the late quaternary in an attempt to elucidate the palaeoenvironment of this marine lacustrine system and hence constrain the rates of sea level changes high precision measurements 0 0036 of 87sr86sr ratios are reported for individual fossil ostracod valves these valves were extracted from two piston cores taken from the deepest part of the gulf of carpentaria single valves weighing 20 g 40 g and containing a total of 10 8 g to 2 10 8 g of sr have been analysed at the bottom of the main core in a depth interval equivalent to an age of 36 000 to 40 000 years valves from the ostracod species cyprideis have 87sr86sr ratios of from 0 70955 2 to 0 70967 2 sr 6 1 to 7 9 from 26 000 years to 22 000 years slightly higher but relatively constant 87sr86sr ratios of from 0 70998 2 to 0 71016 2 sr 12 2 to 14 9 are present the highest sr ratios are found in ostracod valves of 13 000 years age which have values from 0 71034 2 to 0 71039 2 sr 17 2 to 18 0 all these values are significantly greater than that of contemporary seawater and are indicative of continental sources with high 87sr86sr ratios significantly lower 87sr86sr ratios of from 0 70918 2 to 0 70961 2 sr from 0 8 to 7 0 are found in ostracods younger than 12 000 years and ratios identical to modern seawater 87sr86sr 0 70912 2 sr 0 0 are present in the upper 2 cm of core which is 5 000 years in age the variations in 87sr86sr ratios in ostracod valves from the carpentaria basin are consistent with a lacustrine environment from 36 000 years to 12 000 years followed by a transgressive marine sequence which commenced in the gulf of carpentaria 12 000 years ago this marine transgression was a result of sea level rising above the 53 m relative to present day sea level arafura sill sr isotope ratios identical to that of modern seawater were however only obtained when the 12 m torres strait sill was opened to the coral sea which occurred 8 000 to 7 000 years ago the marked decrease in sr isotopic ratios at the bottom of the core may be due to flow of the fly river from new guinea prior to its diversion into the coral sea or more probably a transitory input of marine water into the carpentaria basin during a relatively high sea level 40 000 years ago it is suggested that the highest asr values present 13 000 years ago reflect increased rainfall in the gulf area of northern australia which is attributed to a southwards migration of the monsoonal rainfall pattern at that time in contrast to some other chemical indicators of palaeoenvironments the asr results of this study provide definitive and unambiguous resolution of marine versus non marine environments and can thus be used to resolve with great accuracy transgressive regressive sequences

new insights into the palaeoenvironmental evolution of magdala ancient harbour sea of galilee israel from ostracod assemblages geochemistry and sedimentology abstract despite several studies have focused on the past bio sedimentary response of the mediterranean coastal areas to ancient seaport activities only few geoarchaeological and palaeoecological data are available on strictly lacustrine harbours to date at the archaeological site of magdala taricheae sea of galilee north israel an interdisciplinary study combining ostracod fauna composition and shell chemistry with sedimentology geochemistry of sediments and archaeological data was undertaken on the sedimentary succession buried beneath the roman harbour structures in correspondence of two key sections this approach provided detailed information about past environmental changes otherwise not visible into a high resolution pottery based chronological framework at the transition from a natural pre harbour to anthropogenically influenced harbour lacustrine depositional setting new bio sedimentary and archaeological pottery data document that remarkable hydrodynamic and hydrochemical changes took place during the hellenistic period from the 3 rd 2 nd century bc to the first half of the 1 st century ad in response to the construction of the oldest magdala harbour installations and possibly to the following hasmonean structures the high v cr concentrations observed in the harbour sediments and the substantial increase of ostracod species pseudocandona albicans preferring slow moving waters and fine grained substrates point to the establishment of a semi enclosed shallow and organic rich setting coupled ostracod geochemical analyses also testify to an alkali ions na and k enrichment within whole sediment samples reasonably driven by increasing evaporation in response to the partial isolation of the lake margin the increase in sodium and potassium concentrations is accompanied by the sudden appearance of heterocypris salina a brackish tolerant species and by the almost absolute dominance of noded valves of cyprideis torosa whose shells are enriched in na k and cl the positive covariance between na 2 o k 2 o values and the frequencies of noded c torosa seems to confirm the relation between node development and changes in ionic concentration within hypohaline settings

multiproxy reconstruction of the middle miocene požega palaeolake in the southern pannonian basin ne croatia prior to the badenian transgression of the central paratethys sea abstract the pannonian basin of croatia is the largest back arc extensional basin on the european continent located between the alps carpathians and dinarides syn rift subsidence started at 18 ma and predated the onset of the miocene climate optimum mco 17 14 7 ma in this paper we investigate the evolution of the fluvial lacustrine palaeoenvironment just prior to the transgression of the central paratethys sea studies are based on a 17 m thick section of the po ega palaeolake in the southern pannonian basin using palaeobiological mollusks ostracods palynomorphs fish otoliths mineralogical and sedimentological data our results reveal fluctuating freshwater and brackish conditions and a pulsating water budget which we relate to phases in which the basin was alternatively hydrologically open and closed we infer that the alternating environmental conditions can be best explained by dry and wet periods respectively droughts produced stagnant conditions algae overproduction and increased salinity levels supporting the survival of sporadically invading brackish water species the wet periods on the other hand led to lake highstand episodes expansion of lake area and to the widespread development of profundal facies the lake basin eventually became overfilled and connected through outflowing rivers with the central paratethys sea however the absence of brackish marine assemblages in the po ega palaeolake nevertheless indicates that there was no marine water inflow from the central paratethys at that time

geochemistry of ostracode calcite part 2 the effects of water chemistry and seasonal temperature variation on candona rawsoni abstract reconstruction of lake paleochemistry from the isotope and trace element composition of fossil ostracodes requires an understanding of geochemical variations induced by the seasonality of shell formation monthly field collections of live candona rawsoni from two hyposaline lakes in the eastern dakotas reveal large variations in 18 o values 2 5 o and mg ca and sr ca ratios up to 35 among individual adults within the same assemblage because the measured variations in water chemistry were small the amplitude of ostracode 18 o and mg ca variations must result from seasonal temperature variation ostracode sr ca ratios which should be temperature independent shows strong positive covariance with shell mg ca these results imply that sr uptake in ostracode calcite increases with the mg content of the shell the partitioning coefficient for mg on the other hand appears to decreases at high values of mg ca in the host water the geochemical variability in the field collections indicates that c rawsoni populations are composed of multiple overlapping generations that attain maturity at different times many juveniles apparently undergo several molts in mid summer and persist as penultimate instars a 1 into the following spring geochemical analysis of late instar juvenile c rawsoni from lacustrine sedimentary records is likely to provide information on mid summer conditions large numbers of fossil ostracodes should be analyzed from each stratigraphic interval to eliminate seasonal noise from the paleochemistry records of temperate region lakes

holocene paleoclimate inferred from salinity histories of adjacent lakes in southwestern sicily italy marked uncertainties persist regarding the climatic evolution of the mediterranean region during the holocene for instance whether moisture availability gradually decreased remained relatively constant or increased during the last 7000 years remains a matter of debate to assess holocene limnology hydrology and moisture dynamics the coastal lakes lago preola and gorgo basso located in southwestern sicily were investigated through several stratigraphic analyses of ostracodes including multivariate analyses of assemblages transfer functions of salinity and biochemical analyses of valves sr ca 18o and 13c during the early holocene the gorgo basso and lago preola ostracode records are similar after an initial period of moderate salinity 1690 6100 mg l from ca 10 000 8190 cal yr bp syndepositional or diagenetic dissolution of ostracode valves suggests that salinity declined to 250 mg l from ca 8190 to 7000 cal yr bp at both sites after ca 6250 cal yr bp the ostracode records are strikingly different lago preola became much more saline with paleosalinity values that ranged from 2270 to about 24 420 mg l we suggest that lago preola s change from a freshwater to mesosaline lake at about 6250 cal yr bp was related to sea level rise and resulting intrusion of seawater influenced groundwater in contrast gorgo basso remained a freshwater lake the salinity of gorgo basso declined somewhat after 6250 cal yr bp in comparison to the early holocene ranging from about 550 to 1680 mg l cypria ophtalmica a species capable of rapid swimming and flourishing in waters with low dissolved oxygen levels became dominant at approximately the time when greek civilization took root in sicily 2600 cal yr bp and it completely dominates the record during roman occupation roughly 2100 to 1700 cal yr bp these freshwater conditions at gorgo basso suggest high effective moisture when evergreen olive oak forests collapsed in response to increased greco roman land use and fire ostracode valve geochemistry sr ca 18o suggests significant changes in early vs late holocene hydrochemistry either as changes in salinity or in the seasonality of precipitation harmonizing the autecological and geochemical data from gorgo basso suggests the latter was more likely with relatively more late holocene precipitation falling during the spring summer and fall than winter compared to the early holocene our ostracode inferred paleosalinity data indicate that moisture availability did not decline during the late holocene in the central mediterranean region instead moisture availability was lowest during the early holocene and most abundant during the late holocene

coastal evolution and holocene ostracods in melides lagoon sw portugal abstract a multidisciplinary study covering sedimentology texture carbonate and organic matter content clay mineralogy geochemistry major minor and trace elements isotopes palaeoecolgy ostracods and isotopic dating 14 c has been carried out on two long cores mb 40 0 m and migm 34 0 m retrieved from the barrier and the alluvial plain margining the melides lagoon south western coast of portugal the interpretation of the whole data set allowed the establishment of an evolutionary model for this lowland since the late glacial this model includes four stages it starts with a fluvial terrestrial environment replaced by an estuarine to fully marine one circa 9500 cal bp due to the rapid rise in sea level recorded during the first phase of the holocene transgression the deceleration of sea level rise favoured the emplacement of a sandy barrier circa 5900 cal bp that promoted the differentiation of a coastal lagoon which has been progressively filled with fluvial sediments the ostracod fauna in both locations includes 38 species of littoral to sublittoral phytal marine forms mainly urocythereis britannica carinocythereis whitei loxoconcha rhomboidea pontocythere elongata semicytherura sella semicytherura acuta basslerites cf berchoni hiltermannicythere emaciata and brackish water forms cyprideis torosa loxoconcha elliptica which clearly characterize the signature of both the marine and lagoonal episodes respectively

age and palaeoenvironment of the enigmatic arternian interglacial evidence from the muschelton at voigtstedt hackelsberg thuringia central germany abstract the arternian interglacial has been established on the basis of a pollen record within the muschelton shell clay horizon near voigtstedt type locality in the surroundings of artern in central germany this horizon is older than the early middle pleistocene voigstedt lehmzone loam zone layers which overlie the muschelton due to the lack of a comprehensive fossil record the age of the arternian interglacial has long been disputed as has its palaeoenvironmental conditions here we present the results of new interdisciplinary studies from new exposures of the muschelton at voigtstedt hackelsberg palaeomagnetic screening revealed dominantly reversed polarity of the muschelton partly overprinted by normal magnetisations fossil content consists of identifiable plant mollusc ostracod fish small and large mammal remains the stratigraphic range of the recorded taxa in combination with the palaeomagnetic reverse polarity and amino acid racemization studies indicate an early pleistocene age for the arternian interglacial within the range of mis marine isotope stages 29 21 c 990 810 ka in contrast to interpretations in former studies our investigations of the muschelton from voigtstedt hackelsberg do not indicate subarctic climate prior to or following a clearly separated interglacial as evidence for high summer temperatures was present throughout the muschelton sequence the changes between cold and temperate stages in the pollen record can be best explained by changes in continentality this result confirms climatic inferences for pollen records of other early and early middle pleistocene sites in central europe

stratigraphic evidence for a high marine shore line during the late weichselian deglaciation on the kullen peninsula southern sweden mineral magnetic properties and the carbon content of a sediment sequence in lake kullatorpssjon on the kullen peninsula in northwest scania southern sweden were investigated diatom and ostracod analyses were undertaken for palaeoecological reconstruction and a chronology was constructed from accelerator mass spectrometry ams radiocarbon dating of terrestrial plant remains and mosses five stratigraphical units were identified units 1 5 from oldest to youngest the two lowermost units consist of clay the lowest clay unit 1 is strikingly black 2 m thick and has magnetic properties dominated by high concentrations of authigenic greigite fe3s4 in contrast the overlying clay unit 2 is grey 1 18 m thick and has magnetic properties dominated by low concentrations of detrital magnetite fe3o4 a major palaeoecological change is reflected in the diatom flora and ostracod fauna at the transition from unit 1 to unit 2 the sediment stratigraphy geochemical mineral magnetic and palaeoecological analyses also point to a significant change in depositional environment at this transition which is proposed to represent the isolation of lake kullatorpssjon from the kattegat sea earlier investigations have determined the marine limit to ca 65 m a s l on the kullen peninsula the separate independent lines of evidence presented here however suggest that the late weichselian marine limit developed at 85 90 m a s l at the deglaciation ca 17 200 cal yr bp ca 14 500 yr bp this limit is ca 25 m higher than assumed previously lake kullatorpssjon formed ca 1000 cal yr later when the basin became isolated from the kattegat sea copyright c 1999 john wiley sons ltd less

mid to late holocene relative sea level change in poole harbour southern england a foraminiferal transfer function for mean tide level mtl is used in combination with ams radiocarbon dated material to construct a record of relative sea level rsl change from poole harbour southern britain these new data based on multiple cores from duplicate sites indicate four phases of change during the last 5000 cal calendar yr i rising rsl between ca 4700 cal yr bp and ca 2400 cal yr bp ii stable to falling rsl from ca 2400 cal yr bp until ca 1200 cal yr bp iii a brief rise in rsl from ca 1200 cal yr bp to ca 900 cal yr bp followed by a period of stability iv a recent increase in the rate of rsl rise from ca 400 200 cal yr bp until the present day in addition they suggest that the region has experienced long term crustal subsidence at a rate of 0 5 mm c 14 yr 1 although this can account for the overall rise in mtl observed during the past 2500 yr it fails to explain the changes in the rate of rise during this period this implies that the phases of rsl change recorded in the marshes of poole harbour reflect tidal range variations or eustatic fluctuations in sea level copyright 2001 john wiley sons ltd

comparative ecological analysis of the ostracod faunas from low and high polluted southwestern spanish estuaries a multivariate approach abstract the distribution and abundance of both living and total ostracod populations from the estuaries of the southwestern spanish coast are discussed a total of 68 species were obtained from 120 bottom samples collected in the channels channel margins and salt marshes four assemblages were recognized in this area a urocythereis oblonga assemblage with marine species well represented in sandy substrates located near the mouths b loxoconcha rhomboidea assemblage mainly developed in the quiet tidal channels conected with the main channels of the marine domains c loxoconcha elliptica assemblage enclosing the most cosmopolitan and euryhaline species very abundant in muddy sediments and low to moderate hydrodynamic conditions and d leptocythere porcellanea assemblage only observed in the clayey silty channel margins of the most protected ebb channels in these transitional environments very unfavorable conditions for the ostracod development were found in a the erosional channels and channel margins b most of the salt marsh samples with high subaerial exposure and c sectors with high metallic pollution levels and acidic waters

geochemistry and oxygen isotope composition of main group pallasites and olivine rich clasts in mesosiderites implications for the great dunite shortage and hed mesosiderite connection evidence from iron meteorites indicates that a large number of differentiated planetesimals formed early in solar system history these bodies should have had welldeveloped olivine rich mantles and consequentially such materials ought to be abundant both as asteroids and meteorites which they are not to investigate this great dunite shortage we have undertaken a geochemical and oxygen isotope study of main group pallasites and dunitic rocks from mesosiderites oxygen isotope analysis of 24 main group pallasites 103 replicates yielded a mean 17o value of 0 187 0 016 2 which is fully resolved from the hed 17o value of 0 246 0 014 2 obtained in our earlier study and demonstrates that both groups represent distinct populations and were derived from separate parent bodies our results show no evidence for 17o bimodality within the main group pallasites as suggested by a number of previous studies olivine rich materials from the vaca muerta mount padbury and lamont mesosiderites and from two related dunites nwa 2968 and nwa 3329 have 17o values within error of the mesosiderite average this indicates that these olivine rich materials are co genetic with other mesosiderite clasts and are not fragments from an isotopically distinct pallasite like impactor despite its extreme lithologic diversity the mesosiderite parent body was essentially homogeneous with respect to 17o a feature best explained by an early phase of large scale melting magma ocean followed by prolonged igneous differentiation based on the results of magma ocean modeling studies we infer that mg rich olivines in mesosiderites formed as cumulates in high level chambers and do not represent samples of the underlying mantle by analogy recently documented mg rich olivines in howardites may have a similar origin although the dawn mission did not detect mesosiderite like material on vesta evidence linking the mesosiderites and heds includes i their nearly identical oxygen isotope compositions ii the presence in both of coarse grained mg rich olivines iii both have synchronous lu hf and mn cr ages iv there are compositional similarities between the metal in both and v mesosiderite like material has been identified in a howardite breccia the source of the mesosiderites remains an outstanding question in meteorite science the underrepresentation of olivine rich materials amongst both asteroids and meteorites results from a range of factors however evidence from pallasites and mesosiderites indicates that the most important reason for this olivine shortage lies in the early catastrophic destruction of planetesimals in the terrestrial planet forming region and the subsequent preferential loss of their olivine rich mantles

deglaciation shore displacement and early holocene vegetation history in eastern middle sweden the sedimentary record at lake vibysjo lake basin is situated close to the narke strait where the main water exchange occurred between the vanern basin and baltic basin during the middle and late phases of the yoldia sea stage of the baltic sea c 10 000 9500 14c years bp the area was deglaciated in a glaciomarine environment as reflected by the occurrence of benthic calcareous fossils foraminifera ostracods and the mollusc portlandia arctica gray in the lower most clay units the estimated date of deglaciation 10 440 clay varve years bp suggests that a saline bottom water current entered the baltic basin shortly after the high areas south of lake vibysjon became free of ice the brackish water fauna occurs during a regional betula empetrum hippophae pollen zone which in southern sweden is correlated with the early preboreal the isolation of the lake vibysjon basin is dated to 8100 14c years bp and occurred during the last part of the ancylus lake stage based on investigations of other bas

centennial to millennial scale change of holocene shallow marine environments recorded in ostracode fauna northeast japan abstract using the record of shallow marine ostracode fauna and sediment grain size data from an 865 cm long piston core obtained from mutsu bay northeast japan paleoceanographic changes of the bay were determined at high resolution for the early to middle holocene changes in the relative frequencies of several species showed periodicities of 1300 1800 years similar to bond cycles at around 10 300 cal yr bp and again at 9500 9300 cal yr bp cold water strongly influenced the bay owing to cooling events since at least 10 200 cal yr bp the tsugaru warm current influenced the surface waters and since ca 7400 cal yr bp also the bottom waters of the bay since ca 8400 cal yr bp the water depth rapidly increased and peaked at 7000 5900 cal yr bp due to global sea level rise subsequently a drop of water temperature and sea level in the bay at 5900 and around 4000 cal yr bp influenced the composition of the ostracode assemblages these millennial scale oscillations in relative sea level and bay temperature during the holocene can be correlated to paleoclimate records elsewhere

holocene evolution of the danube delta an integral reconstruction and a revised chronology abstract the danube delta is one of the few large deltas in the world the evolution of which has involved numerous and varied episodes within a complex framework of interactivity between river sediment supply allochthonous sediments supplied by longshore currents marine dispersing forces vertical movements neotectonics sediment compaction and sea level the resulting complex morphology comprises diversified landscapes varying from labyrinthic net of channels and lakes fluvial delta to massive tracts of monotonous reed marshes large lagoons divided by barriers or beach ridge plains accommodating large transgressive dunefields maritime delta whilst previous studies have focused on various sectors of the danube delta the current paper proposes for the first time an integral reconstruction of delta evolution based on existing and new sedimentological and morphological analyses and absolute ages ams 14 c and osl enabling a comprehensive synthesis in terms of both evolutionary phases and growth patterns a chronological framework was established for all the deltaic lobes and beach ridge plains highlighting the relationship between formation timespan growth rates and the resultant morphology this work unveils the early stage of delta formation including the reconstruction of delta front advancement into danube bay old danube lobe prior to 7 5 5 5 ka and initial spit barrier development 6 7 6 5 5 8 ka inception of the bayhead delta started 1000 yr before the relative stabilization of sea level and of the initial spit formation the original fluvial delta plain topography is now buried at a depth of 4 6 m depth below the present topography representing the current stage of fluvial aggradation as a result of subsidence and sea level rise regarding the maritime delta six large open coast lobes developed in the last six millennia of which four were formed by the sf gheorghe branch attesting the long uninterrupted activity of this branch whereas the other two were created respectively by the sulina and the chilia branches the evolution of each lobe is derived from successive chronological shoreline positions and discussed in relation with changes in danube discharge special attention has been paid to their growth stages and progradation rates for the southern delta we bring in new arguments for an active southern distributary the dunav derived from the sf gheorghe branch that formed successive open coast lobes between 2 6 and 1 3 ka additionally we discuss the effects of modern anthropogenically driven fluvial sediment reduction on the morphology and morphodynamics of the active lobes of the danube

the relationship between ostracod distribution and sediment grain size abstract sediment samples from an area seaward of the river crouch in the thames estuary have been analysed for their particle size distribution and later picked over for ostracods the sediments were classified into sediment types and three depositional sub environments were recognised viz intertidal flat sandbank and tidal channel study of the ostracods showed that three distinct faunas characterise the same three environments log grain size probability plots have been used to show a relationship between ostracod distribution and sediment grain size

magnesium content of non marine ostracod shells a new palaeosalinometer and palaeothermometer abstract ostracods are microcrustaceans with calcitic carapaces each consisting of two valves or shells that grow by moulting and regeneration of sequentially larger valves up to nine times before reaching maturity the mg content of these valves is species dependent and is a function of their growth stage and the temperature salinity mg content and mg ca ratio of their host water newly formed partly calcified valves of the non marine nektic ostracod mytilocypris henricae have high mg contents 100 000 ppm mg in caco3 at individual shell weights of 2 g this relative mg content decreases as calcification proceeds until shell weights exceed 120 g whereupon the mg content is constant and useful as an indicator of the ostracod s environment mg ca ratios in individual ostracod valves from several species of the genera mytilocypris and australocypris from culture experiments and a series of australian lakes indicate that the valve s mg content increases as a function of increasing temperature and salinity within the range 11 25 c and for waters containing 24 2325 ppm mg the molar mg ca ratio in these ostracods fully calcified valves increases by 0 0015 or 370 ppm mg in caco3 per 1 c and per change of 125 ppm mg in solution for most mainland australian lakes a change in water composition of 125 ppm mg corresponds to a change of 3 5 in salinity for a given mg content of a lake the mg ca ratio of the water may vary within the range of common lacustrine values without significantly affecting mg uptake in the ostracod valves these relationships can provide palaeosalinities and or palaeotemperatures for ostracods recovered from continental sediments for mg partitioning an increase in temperature and salinity produce increased mg content in ostracods whereas for 18o fractionation in biogenic calcite an increase in temperature produces a decrease in 18o of the ostracod and an increase in salinity leads to an increase in 18o of the ostracod thus a combination of 18o and mg measurements on non marine ostracods should enable unique resolution of palaeotemperature and palaeosalinity variations

late quaternary lacustrine ostracoda and their implications for hydro climatic variation in northeastern tibetan plateau abstract ostracoda from non marine waters have a significant potential role in monitoring ecological conditions and reconstructing paleoenvironments during the last decades the increase in research on ostracods on the tibetan plateau tp has been achieved although there are still taxonomical and ecological problems in their application in quaternary studies the aim of this review is to summarize the occurrences of ostracods in surface samples from four selected lakes qinghai lake lake donggi cona lake kuhai and hala lake along the modern monsoon marginal zone on the northeast tibetan plateau and to compare the ostracod associations in sediment cores from different sites with available proxy data after re evaluation of chronologies in order to reconstruct hydroclimatic conditions and monsoon influence during the late quaternary comprehensive reanalysis of ostracod data from selected lakes including 3 closed and 1 open lake basins on the northeastern tp shows that their occurrence and disappearance responded sensitively to salinity and related water depth changes during the late quaternary this could lead to a re interpretation of other proxy data related to hydro climatic interpretation ostracod based reconstructions of lake level changes along the modern summer monsoon marginal zone of the northeastern tp during the late quaternary indicate an overestimation of the contribution from monsoonal rainfall to strong lake level changes while the glacier snow meltwater supply was underestimated in previous studies this inference sheds more light on moisture source and the interplay between westerlies and asian summer monsoon on the northern tp

uk intertidal foraminiferal distributions implications for sea level studies foraminiferal assemblages have been collected from ten intertidal study areas situated on the east south and west coasts of the uk the assemblages display a vertical zonation which indicates that the distribution of foraminifera in these intertidal environments is usually the direct function of altitude with the duration and frequency of intertidal exposure the most important factors multivariate analyses separate foraminiferal assemblages into two faunal zones a high and middle marsh zone consisting of differing abundances of jadammina macrescens trochammina inflata and miliammina fusca and a low marsh and tidal flat zone dominated by calcareous foraminiferal species notably elphidium williamsoni haynesina germanica and quinqueloculina spp these faunal zones are similar to those in other mid latitude cool temperate intertidal environments although there are spatial and temporal variations between areas the altitudinal ranges of the faunal zones are employed to identify the vertical relationship of the local environment in which the assemblage accumulated to a reference tide level

sedimentary evolution of the north norfolk barrier coastline in the context of holocene sea level change holocene sediments of the north norfolk coast nnc between weybourne and hunstanton have been studied using geophysical sedimentological biofacial and dating techniques new cores and refraction seismic data have defined the topography of the pre holocene surface and show that the nnc sediment prism is underlain by an east west trending quaternary trough probably a palaeo river valley the age of the holocene fill has been dated using radiocarbon and luminescence dates while sedimentation rates were constrained by and compared with modern rates using radionuclide data the holocene sediments are divided into a sandy barrier lithofacies association lfa and a muddy silty peat back barrier lfa the oldest holocene sediments are peats formed on an undulating till surface these peats were forming by 11 10 cal ka bp and continued to form until at least 7 cal ka bp in a number of places as holocene sea level rose marine mudflat and saltmarsh environments began to form between 7 and 6 cal ka bp east of holkham and around 6 cal ka bp or younger west of holkham a marked erosion surface between the barrier and back barrier lfa in the holkham to burnham overy area is imperfectly dated at 3 cal ka bp but suggests the sediment prism has thinned by about 3 km over 6 to c 3cal ka bp this surface probably records the westward progress of laterally migrating tidal channels that caused back barrier sediment erosion along with shoreface processes as sea level rose small scale regressive and transgressive saltmarsh sequences occur at different elevations along strike but cannot be correlated suggesting that the control on saltmarsh and mudflat development is autocyclic rather than allocyclic generally transgressive and regressive events are related to disposition of coastal barriers and these are superimposed on a general facies evolution governed by regional sea level change predictions about how this barrier coastline might respond to increased rates of regional sea level change caused by global warming or climatic events like increased storminess require an understanding of how specific segments of the coastline have responded over millennial time scales this longer term evolution provides the baseline information for decision making and management strategy it is likely that sandy sediment supply is limited on the nnc and this implies that the barriers will continue to move landward probably at increased rates relative to today suggesting that parts of the nnc will become more vulnerable to erosion and flooding

tracing sea level changes during the mid holocene in the southern mediterranean coast an example from the gulf of gabes abstract mid holocene sea level emergence was recorded along a mid latitude coastal site in the gulf of gabes tunisia in beach rock deposits however the post emergence sea level curve and associated hydro sedimentary processes have rarely been documented this study presents new records of sea level changes along the tunisian coast since the mid holocene each phase of the sea level curve was evidenced and supported by lithostratigraphic morphological and archaeologic markers post emergence sea level fall due to postglacial isostatic rebound was recognized in regressive sequences which vary depending on available accommodation space from a small pocket beach to a well developed dune system sea level stabilization following isostatic rebound has promoted the end phase deposits of the regressive sequences however this stability was interrupted during the late holocene by a high energy storm event that accumulated a transgressive boulder unit at 2 m above present shape and disposition of the boulder ridge behind a prograding modern shoreline suggests that sea level has not changed during the late holocene the existence of a roman fish pond on the upper foreshore confirms stability of sea level during the last two millennia the combination of lithostratigraphic morphological and archaeologic markers represents a tool for improving the accuracy of dating of erosional and depositional periods in mid coastal sections

human impact on holocene sediment dynamics in the eastern mediterranean the example of the roman harbour of ephesus during the past millennia many erosion and accumulation processes have been modified by anthropogenic impact this holds especially true for the environs of ancient settlements and their harbours along the mediterranean coasts our multi proxy investigations in the roman harbour and the harbour canal of ephesus western turkey reveals that humans have significantly triggered soil erosion during the last three millennia since the eighth century bc and especially since the hellenistic period a high sed imentation rate indicates fast alluviation and delta progradation of the kucuk menderes deforestation agriculture especially ploughing and grazing especially goats were the main reasons for erosion of the river catchment area one consequence was significant siltation of the hellenistic roman harbour basin this sediment trap archives the human impact which was strongly enhanced from hellenistic roman to byzantine times second first centuries bc to the sixth seventh centuries ad evidenced by high sedimentation rates raised values of heavy metal contaminations lead pb copper cu the occurrence of fruit tree pollen and of intestinal parasites from the middle to the end of the first millennium ad the influence of ephesus declined which resulted in a decrease of human impact studies of several ancient settlements around the mediterranean sea tell a comparable story they also confirm that during their most flourishing periods the human impact totally overprinted the climatic one to detect the latter geo bio archives of relatively pristine areas have to be investigated in detail

ionospheric localisation and expansion of long period pi1 pulsations at substorm onset 1 we examine the initial ionospheric localisation and expansion of pi1 pulsations associated with a substorm onset observed on 1st november 2006 with the combined carisma and themis gmag network of ground based magnetometers we demonstrate how the first ionospheric pulsation disturbance lies in the long period pi1 band the long period pi1 pulsations at substorm onset are initially localised in longitude and expands away from an epicentre in the ionosphere with 16 s timing between stations we further establish a link between the location of the downward field aligned current fac element which subsequently develops within the substorm current wedge scw and the initial location of the onset of long period pi1 pulsations the arrival of the initial long period pi1 wavepacket demonstrates the importance of global networks of ground based magnetometers for probing substorm onset the pi1 expansion proceeds westward at a rate of approximately 1 mlt hour per 20 seconds representing a very rapid expansion of the pi1 signal at the ground the resolution of the pi1 localisation and the rate of expansion suggest pi1 waves can play an important role in studies of the causal sequence of energy release in substorms

palaeoecology and geochemistry of shallow marine ostracoda from the sand hole formation inner silver pit southern north sea abstract ostracods were obtained from the sand hole and swarte bank formations of tappin 1991 in bgs borehole 81 52a cored from the inner silver pit southern north sea the faunal assemblages were dominated by sarsicytheridea punctillata elofsonella concinna and acanthocythereis dunelmensis the assemblages recovered reflect a transition from glaciomarine conditions in the swarte bank formation up into a cold temperate marine environment in the sand hole formation with deteriorating temperatures indicated at the top of the interval studied the palaeoecology of the ostracod assemblages recovered is compared to foraminiferal data from the same section and to ostracod data from other hoxnian holsteinian sites in north western europe these data are also discussed in the light of evidence indicating that there was a barrier across the southern north sea when the sediments examined were deposited sarsicytheridea were used for trace element mg ca sr ca and stable isotope 18 o 13 c analyses a calibration equation for the calculation of temperature from mg ca ratio was successfully established from analysis of modern sarsicytheridea modern sr ca data could not be used to establish a calibration for salinity since there was too much scatter in the data ostracods were also analysed to examine the changing ratios of mg and sr as a proxy for temperature and salinity changes in the hoxnian of the southern north sea mg ca data indicated a deterioration in temperature from 36 20 m to the top of the section studied of 9 c oxygen stable isotopic analyses from the same species measured through the same core intervals did not exhibit a trend but their values were indicative of normal marine salinities carbon stable isotope analyses performed at the same time as the oxygen analyses indicate that there may have been high productivity in the region of deposition of the sand hole formation implying deposition in a region of freshwater influence

a high energy deposit in the byzantine harbour of yenikapi istanbul turkey abstract a byzantine harbour theodosian harbour has been uncovered during excavations at yenikapi with a stratigraphic sequence spanning the past 7000 bp in the marine part of the sedimentary sequence a high energy deposit has been interpreted as being of tsunami origin and related to the earthquake of 557 ad this paper presents a bio sedimentological analysis of this facies the unit is characterised by coarse sands and gravels containing reworked material such as woods bones marble blocks amphora fragments ceramics coins shells and plant remains the thickness of the facies varies between 10 and 100 cm the sediment matrix is poorly sorted with skewness values indicative of a sub tidal fine sand environment many of the marine taxa have been reworked and diverse ecological assemblages are represented lagoonal coastal and open marine species this unit is divided into three facies consistent with different phases of the tsunami drowning and water retreat the basal facies corresponds to two tsunami wave trains and the upper facies indicates the backwash flow

the environs of elaia s ancient open harbour a reconstruction based on microfaunal evidence during hellenistic and roman times elaia the harbour city of ancient pergamum was an important place of trading and traffic intense mercantile and military activities are documented by literary sources and archaeological evidences geomagnetic and geoelectric investigations detected building structures close to the ancient coastline which are interpreted as ship sheds the aim of this study was to reconstruct the coastal evolution particularly with regard to harbour related facilities for that purpose a 10 m long sediment core was drilled in the area of the ancient open harbour immediately in front of the supposed ship sheds it was studied with the tools of micropalaeontology geophysics sedimentology and geochemistry to improve the reconstruction of the palaeoenvironmental conditions reference samples of modern environments of the area were analysed as indicated by marine ostracod and foraminifer taxa the sediment core shows from bottom to top that the initially fully marine conditions changed to a more restricted fauna indicative for a more sheltered bay with brackish waters this layer dates to hellenistic times it can however be shown that the siltation process had produced a lagoon system already several hundred years bc the elaia embayment was first used as a natural harbour it was equipped with breakwaters in the hellenistic period the progressive siltation caused the abandonment of the harbour in late roman times

multi proxy reconstruction of holocene paleoenvironments from a sediment core retrieved from the wadden sea near norderney east frisia germany abstract the coastal area of the southern north sea passed through several stages of development during the holocene starting with swamps and bogs on pleistocene sands these were covered due to the rising sea level by brackish and intertidal sediments with intercalated peat layers indicating repeated shoreline replacements such sedimentary archives are excellent sources for environmental reconstructions and potentially suited to deliver a regional sea level curve we analysed a 4 6 m long sediment core recovered south of the island of norderney east frisia germany using a multiproxy approach the record comprises a vertical stack of changing sedimentary facies including a basal peat and a second peat layer intercalated between marine sediments which provides a sedimentological record of local coastal evolution since 7000 cal bp high resolution stratigraphic geochemical and paleobiological analyses enables reconstructing environmental variability in response to sea level changes including a short lived transgressive regressive cycle this took place around 6000 cal bp and lasted only a few hundred years our multiproxy approach demonstrates that the combined analyses of geochemical and biological parameters in concert with statistical evaluation are indispensable for the reconstruction of coastal evolution and short term sea level fluctuations

multi proxy evidence for holocene lake level and salinity changes at an loch mor a coastal lake on the aran islands western ireland abstract curves for holocene lake levels and salinity changes are presented for an loch mor a small oligohaline lake on the aran islands off the west coast of ireland based on palaeoecological investigations of a 12 m long lake sediment core new insights are also provided into holocene sea level change in the galway bay region particular emphasis has been placed on the ostracod fauna both past and present salinity and lake level changes were reconstructed from the fossil ostracod assemblages based on the known tolerances of individual species and on the assemblages as a whole additional evidence was provided by other proxies including strontium isotope ratios derived from ostracod shells and other carbonates plant macrofossil and pollen analyses and sedimentological changes the early holocene pre boreal i e 11 5 10 ka was characterised by low lake levels and slightly elevated salinity values probably the result of high evapotranspiration and low precipitation rather than elevated sea levels early holocene plant and animal migration to the island does not seem to have been impeded but relative sea levels were not necessarily so low below 40 m a s l that landbridges were present to the mainland between ca 10 and 8 5 ka relatively high lake levels prevailed at 8 3 and 7 5 ka minor fluctuations lowering of the lake level occurred that are assumed to relate to early holocene abrupt events beginning at 7 05 ka lake levels declined sharply a general trend towards rising lake levels started at ca 6 4 ka and accelerated at ca 5 6 ka as runoff increased as a result of neolithic clearances at ca 4 8 ka lake levels began to rise once again probably in response to changes in rainfall and or evapotranspiration and runoff lower lake levels during the first half of the 1st millennium ad were probably a response to decreased runoff as a result of a drier climate coupled with regeneration of woody vegetation the sharpest rise in both lake levels and salinity began during the ninth century ad which is attributed to a rapid rise in relative sea level

paleoecology of limnic ostracodes a review of some major topics abstract the paleoecology of limnic ostracodes is reviewd in the context of the evolution of their environment in order to understand why there is a rich ostracode fossil record we examine data such as the quantitative and qualitative distribution of living ostracode species and ostracode assemblages ways of describing and limitations importance of biological and physico chemical factors for the local accumulation of high numbers of ostracodes and diversified assemblages is emphasized we discuss the limits of extrapolations of information from ecology to paleocology we stress how paleontological knowledge can be applied to neontological studies the possibility of using holocene ostracodes as indicators of morphometric changes of lakes temperature salinity eutrophication and as a criterion of meromictic conditions is demonstrated relationships between ostracodes and the chemical environment and particularly the morphological response of the carapace are considered e g diversity and qualitative composition of assemblages and chemical stability types of carapace mineralization and ornamentation and chemistry of bottom waters these ideas developed from studies on recent material are tested for limnic cenozoic faunas in the mesozoic the main questions arising from the study of nonmarine ostracodes deal with the possible evaluation of paleosalinities in marginal lagoonal environments purbeck wealden and with evaluation of depth and hydrochemical and paleoclimatological regime in truly lacustrine intracratonic basins some peculiarities of paleozoic nonmarine ostracode assemblages are described the paleoecological cause of changes in diversity of several ostracode groups in the carboniferous and permian is emphasized

strontium isotopic paleontological method as a high resolution paleosalinity tool for lagoonal environments a combined strontium isotopic 87 sr 86 sr and paleontological method is newly applied to a modern lagoon in egypt s nile river delta to test its applicability as a paleosalinity proxy analyses of 22 surficial samples collected throughout the lagoon include 81 sr isotopic analyses of mollusks foraminifera ostracods barnacles bryozoans serpulid worm tubes pore water and gypsum crystals two salinity groups are distinguished in each sample a lower salinity group 1 ppt mixed with a higher salinity group 3 10 ppt that respectively are interpreted as the modern biocoenosis and an older relict fauna the relict fauna denotes higher salinity conditions in the lagoon prior to closure of the aswan high dam 1964 and the modern fauna records freshening of the lagoon recent decreased salinity is a response to regulated nile river flow and increased discharge into manzala of fresh water via canals and drains quantification of this short term salinity change holds promise for study of modern lagoons in other world settings and may provide paleoclimatic information for older lagoon sequences in the nile river delta and the geologic record

palaeoenvironmental indicators from late holocene and contemporary ostracoda of the aral sea abstract the aral sea is a large terminal lake i e having no outflow in south western asia it is diminishing in size and the salinity of the water is increasing due to excessive withdrawal of water for irrigation from the two main rivers flowing into it the biota of the lake has been decimated and the chemical composition changed dramatically since 1960 three short sediment profiles two cores and one section are examined with a view to reconstructing the most recent history of the sea from microfossil assemblages historical and geological records indicate that since its formation aral sea levels have changed such variation may have been accompanied by changes in the chemistry of the sea through increased evaporation or precipitation in the present work analyses of the mg ca and sr ca molar ratios particularly the latter of benthonic ostracoda from the aforementioned cores indicate that although present salinity levels were never attained during the period of deposition of the sections studied past saalinity variation can be inferred oxygen and carbon isotope analyses of ostracoda and mollusca from one of the sections however indicates two possible periods of relative salinity increase

late quaternary sea level changes along the tyrrhenian coast near orbetello tuscany central italy palaeoenvironmental reconstruction using ostracods abstract a multidisciplinary study has been carried out on a 51 m long core drilled on coastal lowlands near the albegna river tuscany central italy both sedimentological and faunal analyses ostracods and molluscs indicate a coastal lagoon environment repeatedly influenced both by the rising holocene sea and the albegna river alluvial inflow 13c 18o mg ca sr ca and 87sr 86sr analyses were performed on cyprideis torosa shells in order to detail the influence of albegna river freshwater on the coastal lagoon water the analytical data illustrate the difficulties of using geochemical proxies in marginal marine settings four radiocarbon dates provide a chronostratigraphy for the early holocene part of the core the data are used to reconstruct late pleistocene to early holocene palaeoenvironments along this part of the coast and show the development of freshwater environments followed by a coastal brackish lagoon formed in response to the initial holocene rapid rise in relative sea level an attempt is made to relate sediments and age data from the core to the relative sea level curve for the tyrrhenian sea

holocene ostracoda crustacea from the shallow lake vrana dalmatia croatia and their paleoenvironmental significance abstract lake vrana in dalmatia is a coastal karstic brackish water environment characterized by a high species richness of ostracods that evolved into their current morphologies during the holocene the results of this study reveal five ostracod zones within an 11 m sediment core taken from the central part of the lake this sedimentary sequence reveals significant changes in both depositional and environmental conditions at local and regional scales the oldest freshwater deposits interpreted as the late pleistocene holocene transition mainly comprise the species candona neglecta juxilyocypris cf schwarzbachi hungarocypris madaraszi darwinula stevensoni and mixtacandona sp although the lake had not formed at this time it is well known that the living environment of most ostracod species is connected to flooded plains marshes rivers springs and interstitial waters in the deepest and oldest sediments within the core from depths between 1101 cm and 945 cm the presence of c neglecta and j cf schwarzbachi are indicative of cold water while the dominant taxa at depths between 945 cm and 874 cm are the brackish species cyprideis torosa and c angulata possibly suggesting the influence of seawater because of the presence of a permeable karstic ridge that separates the lake from the ocean in contrast the dominant ostracod taxa at depths between 874 cm and 813 cm are species typical of freshwater environments subject to colder climatic conditions indicating a marshy low energy wetland we know that the first permanent freshwater body formed at about 8130 cal yr bp a depth of 813 cm while large proportions of pseudocandona marchica heterocypris salina d stevensoni and metacypris cordata are all indicative of warmer shallow waters that are rich in vegetation and have variable water level similarly from 5240 cal yr bp onwards a marine influence within the core is evidenced by the presence of cy torosa while present lake water conditions i e alternating seasonal changes in salinity from freshwater to brackish were established by 2750 cal yr bp the ostracod assemblages in sediments from lake vrana in dalmatia have significant potential for reconstructing the evolution of this lake as well as for understanding environmental changes and rising sea level

holocene marginal marine ostracod successions from the kizilirmak river delta implications for depositional environments and sea level changes at the southern black sea coast abstract holocene delta formations are unique records of regional sea climate interactions the kizilirmak delta is the biggest and richest wetland ecosystem in the black sea region of turkey the black sea was uniquely affected by rising sea levels due to its disconnection from the world oceans during the last glacial period to understand the palaeoenvironmental impact on the delta plain we analysed a 14 5 m long sediment core using palaeoecological ostracod analyses accompanied by a palaeo salinity reconstruction based on sieve pore analysis on the ostracod cyprideis torosa this study depicts the interplay of terrestrial and marine settings forming mesohaline shallow lagoons and deltaic lakes since ca 7 9 ka cal bp lagoons with mesohaline to polyhaline salinities and mesohaline to oligohaline lake environments were identified reconstructed palaeo sea level estimations depict a remarkable environmental variability the lagoon habitats at 7 9 to 7 0 and 5 3 to 4 ka cal bp were dominated by cyprideis torosa marine influence led to ostracod associations with loxoconcha spp and tyrrhenocythere amnicola especially between 7 9 and 7 0 ka cal bp riverine influence in the same period but especially at about 7 7 ka cal bp caused dominating amnicythere spp cyprideis torosa and candona neglecta that characterise short phases of a mesohaline deltaic lake environment at about 7 7 and 7 0 ka cal bp as well as after 4 ka cal bp with a subsequent salinity decrease c neglecta and later on pseudocandona marchica became dominant with an interruption by another short term lagoonal phase that might be associated with a megadrought between 3 7 and 3 0 ka cal bp

late eocene clay boron derived paleosalinity in the qaidam basin and its implications for regional tectonics and climate abstract the qaidam basin located on the northeastern tibetan plateau and containing cenozoic sediments with a maximum thickness of 12 000 m is an ideal place to study the phased uplift of the ne tibetan plateau and regional climate change the estimation of the paleosalinity of sedimentary environments not only helps to evaluate the evolution of lakes in this region but offers insights into contemporaneous climate change we present detailed geochemical and mineralogical investigations from the lacustrine interval of the hongliugou section in the northern qaidam basin to reconstruct salinity fluctuations in the paleolake during the late eocene era 42 0 35 5 ma the clay mineral assemblages mainly contain smectite illite chlorite kaolinite and irregular illite smectite mixed layers clay boron derived paleosalinity estimates equivalent boron content couch s paleosalimeter and b ga ratios along with other proxies sensitive to salinity changes e g rb k ratios and ostracod assemblages collectively indicate an overall brackish sedimentary environment with a higher salinity period at approximately 40 0 39 2 ma this higher salinity period indicates a more arid environment and is probably related to global cooling however the global cooling in late eocene cannot explain the overall stable long term salinity pattern implying that other factors exist we propose that the migration of the yiliping depression depocenter in the northern qaidam and increased orographic rainfall induced by late eocene tectonic activity at the northern margin of the basin might have partly offset the increase in salinity driven by global cooling

holocene coastal change and geoarchaeology at howick northumberland uk the recent discovery of one of the earliest mesolithic occupation sites in northern britain at howick on the northumberland coast in association with multiperiod archaeological evidence nearby highlights the importance of uk coastal settings as focii of human occupation through the holocene environmental evidence from a nearby river valley 8 15 m of sediment ranging in age from about 12 000 cal bp to the present records local and regional environmental change twenty four radiocarbon dates based on plant macrofossils provide a strong chronological framework calcareous microfossil assemblages foraminifera ostracods have been recovered from the fine grained sediments recording a change from marine through to brackish and eventually freshwater conditions between about 8200 and 6500 cal bp a preliminary pollen study of the core has permitted a reconstruction of the regional vegetation as it responded to climatic amelioration and human influence upon the landscape radiocarbon dating and sedimentological evidence indicates a major hiatus between approximately 11 000 and 8000 years bp including the period of mesolithic occupation represented by a 30 cm layer of coarse sands and sandstone pebbles probably the result of a significant high energy event dated to about 8300 cal bp although not a typical tsunami deposit the age and context suggests that this may be associated with the storegga slide event already well documented along the eastern coast of scotland the sedimentary and biological remains at howick record environmental change over much of the holocene and are compared with other environmental change records from the region to provide an environmental framework for the archaeology of this coastline

the use of ostracods from marginal marine brackish waters as bioindicators of modern and quaternary environmental change abstract ostracoda microscopic aquatic crustacea from brackish waters have a great potential for ecological monitoring and palaeoenvironmental analyses in highly variable environments this has been proven in many articles during recent decades but their potential has yet to be fully developed or utilised the analysis of ostracod assemblage composition species distributions eco phenotypic variability and the analysis of stable isotopes and trace elements in ostracod shells provide valuable information on present and past water salinity temperature and chemistry hydrodynamic conditions substrate characteristics climate sea level variations oxygen and nutrient availability this article provides an overview on the application of ostracods from brackish waters for palaeoenvironmental reconstruction in the quaternary and for environmental studies in present day environments

palaeoenvironmental analysis of early pleistocene brackish marshes in the rieti and tiberino intrapenninic basins latium and umbria italy using ostracods crustacea abstract recent palaeontological and sedimentological studies on the upper pliocene lower pleistocene continental deposits of the rieti and tiberino basins latium and umbria italy showed the existence of brackish marshes influenced by the early pleistocene tyrrhenian sea the micropaleontological analyses carried out on five sections cropping out in the northern sector of the rieti basin and on one section cropping out in the southwestern branch of the tiberino basin showed the repeated alternance of two ostracod assemblages the first is characterized by a very abundant ostracod association dominated by cyprideis torosa typical of brackish waters the second one is less rich in specimens and dominated by several species of freshwater candoninae this alternance allowed the recognition of several changes in the water salinity that could be related to many early pleistocene sea level changes palaeosalinities were estimated for both the tiberino and the rieti basin using the morphological analysis of the shell of cyprideis torosa ornamentation nodosities and percentages of sieve type pore canals the obtained palaeosalinity values ranging from freshwater to oligohaline show slightly higher salinities for the tiberino basin located nearer the ancient coastline than for the rieti basin

microbiotic signatures of the anthropocene in marginal marine and freshwater palaeoenvironments the term anthropocene has been proposed to indicate a geological interval character ized by global anthropogenic environmental change this paper attempts to recognize a method by which the anthropocene can be defined micropalaeontologically in order to do this microfloras and microfaunas diatoms macrophytes dinoflagellate cysts foraminifera and ostracods from nearshore waters through to paralic and freshwater aquatic milieux are considered and biotic varia bility with an anthropogenic causation identified microbiotic change can be related to anthropo genically induced extinctions pollution related mutation environmentally influenced assemblage variability geochemistry of carapaces tests floral change related to lacustrine acidification faunal and floral correlation to industrial and agricultural signatures and introduction of exotic species via shipping the influence of humanity on a local scale can be recognized in assemblages as far back as 5000 years bp however widespread anthropogenic change took place in europe and america particularly in the nineteenth and twentieth centuries although in asia e g japan it cannot be observed prior to the twentieth century profound and global biotic change began in the mid twentieth century and if the anthropocene is to be defined in this way then the period 1940 1945 might encompass the biotic base of the interval

a quantitative inference model for conductivity using non marine ostracode assemblages on san salvador island bahamas paleosalinity records from two lakes abstract quantitative records of past environments are needed to understand natural variability in ecosystems and their responses to climate change changes in ostracode assemblages through time can provide such records as ostracode species are sensitive to changes in their local environments before they can be used to indicate past environments however is it necessary to understand how distributions of assemblages change across environmental gradients to that end thirty two lakes on san salvador island bahamas were sampled for both ostracodes and nineteen limnological variables multivariate fuzzy set ordination indicates that change in ostracode assemblages is significantly and independently correlated with three environmental variables electrical conductivity salinity dissolved oxygen and alkalinity a transfer function was created to reconstruct past conductivity since changing conductivity of lakes on san salvador is influenced by changes in climate and sea level a 2 component weighted averaging partial least squares model performed best as a transfer function for conductivity with an apparent r 2 of 0 76 and an r 2 of 0 69 between observed and predicted conductivity as assessed by leave one out cross validation the resulting transfer function was then applied to two mid to late holocene sediment cores from which ostracode assemblages were sampled the late holocene conductivity records show that changes in conductivity of lakes on san salvador are broadly synchronous with times of enhanced enso activity corresponding to elevated conductivity in response to lower atlantic hurricane occurrence these results demonstrate that changing ostracode assemblages through time provide a reliable means to reconstruct past salinity and demonstrates the strong effect of enso on bahamian aridity

different phases of the yoldia sea in the north western baltic proper four sediment cores from the north western baltic proper covering the time from the weichselian deglaciation to the present have been studied main interest is focused on the yoldia stage and especially the duration of the marine phase of this stage the lithological compositions of the sediments and results of different analyses magnetic carbonate ostracods and foraminifera have resulted in a subdivision into five stratigraphical units a e from older to younger unit a was deposited in a glaciolacustrine environment probably during the first non saline phase of the yoldia stage the first ingression of saline water is recorded in unit b brackish water ostracods and foraminifera occur exclusively in this unit which represents the only saline phase of the yoldia stage this phase lasted for less than 120 clay varve years unit c was deposited in fresh water probably during the last phase of the yoldia stage and the ancylus stage the uppermost units d and e are of holocene age and represent different phases of the litorina and post litorina stages

ostracod palaeolimnological analysis reveals drastic historical changes in salinity eutrophication and biodiversity loss in a coastal mediterranean lake the albufera of valencia one of the largest oligohaline coastal lagoons of the iberian peninsula has suffered hydrological and landscape modifications since medieval times this paleolimnological study clears up the controversy about the factors which drove the lake to its present state lithological descriptions ostracod paleoassemblages and cyprideis torosa jones 1850 shell morphological variations and geochemistry 18o 13c and sr ca have been used to reconstruct the lake ecosystem evolution during the last two centuries the sandy sediments at the bottom of l antina core 63 cm presented a typical assemblage of brackish water ostracods with shell derived 18o values inferred salinity and sr cawater characteristic of waters with marine influence however 10 cm above coinciding with a drastic change in lithology ostracod palaeoassemblages and decreased shell 18o indicated a shift to freshwater influences at the top of the sequence inferred salinity suggests oligohaline waters and ostr

stable isotopes sr ca and mg ca in biogenic carbonates from petaluma marsh northern california usa stable isotope sup 18 o sup 16 o and sup 13 c sup 12 c and minor element compositions sr ca and mg ca ratios of ostracodes and gastropods separated from marsh sediments from san francisco bay northern california were used to reconstruct paleoenvironmental changes in petaluma march over the past 700 yr the value of delta sup 18 o in the marsh carbonates reflects changes in freshwater inflow evaporation and temperature mg ca and sr ca in ostracode calcite reflect changes in both freshwater inflow and temperature although primarily reflect temperature changes in the salinity range of about 10 35 per thousand ostracode delta sup 18 o values show a gradual increase by 5 per thousand between 500 yr bp and the present probably reflecting rising sea level and increased evaporation in the marsh superimposed on this trend are higher frequency mg ca and delta sup 18 o variations 3 4 per thousand probably reflecting changes in freshwater inflow and evaporation a period of low mg ca occurred between about 100 300 cal yr bp suggesting wetter and cooler conditions during the little ice age higher mg ca ratios occurred 600 700 cal yr bp indicating drier and warmer conditions during the end of the medieval warm period both ostracode and gastropod delta sup 13 c values decrease up core reflecting decomposition of marsh vegetation which changes from c sub 4 delta sup 13 cmore approximately minus 12 per thousand to cam delta sup 13 c minus 26 per thousand type vegetation over time less

holocene palaeogeographies of the astakos coastal plain akarnania nw greece abstract this paper deals with holocene coastal changes of the astakos plain in akarnania nw greece palaeoenvironmental scenarios are based on the analysis of the lateral and vertical distribution patterns of sedimentary facies sediments from vibracorings were studied using geomorphological sedimentological microfaunal palaeobotanical and geochemical methods a geochronostratigraphy was achieved by 14c ams dating of organic matter we present palaeogeographical maps for different points in time since the mid holocene the evolution of the coastal area was generally controlled by the migration of a complex system of a shallow marine embayment an adjacent lagoonal environment and an adjoining coastal lake forced by the interaction of sea level rise tectonic movements and sediment supply from the hinterland the maximum transgression of the ionian sea took place at circa 5500 cal bc reaching approx 1 1 km inland the lagoon as well as the coastal lake had their largest dimensions around 4500 cal bc indicating a more humid climatic period in the course of a long lasting regression an asymmetric sedimentation pattern developed around 2500 cal bc it was characterized by strong fluvial deposition of the xeropotamos in the western plain and a small and narrow marine embayment with associated lagoonal to limnic coastal water bodies in the eastern plain the latter were related to karstic springs draining the adjacent rigani ridge around 500 cal bc the coastline lay about 200 m landward of its present position possible harbour sites for the ancient polis of astakos are a the area of modern astakos where a mole in a position seawards of the present coast would have guaranteed deep water conditions for anchoring or b the southeastern fringe of the plain where deep water prevailed and the nearby freshwater outlet protected the site from rapid siltation we found increased torrential activity i for the 6th 5th millennium bc ii for the 2nd half of the 1st millennium bc until roman times and iii at the end of the 19th century ad at least the two younger phases are mostly due to anthropogenic soil erosion between the 4th and the 2nd millennium bc a period of ecological stability existed relative changes in sea level for the bay of astakos were reconstructed for the first time since the mid holocene the relative sea level has never reached a higher position than today it rose from 12 50 m b s l at 6200 cal bc via 2 20 m b s l at 500 cal bc to its present level besides eustatic reasons tectonic subsidence due to the half graben structure of the area is the main trigger of the relative rise in sea level

in search of the harbours new evidence of late roman and byzantine harbours of ephesus abstract ephesus greek name ephesos in western turkey was an important harbour city during antiquity the progradation of the kucuk menderes delta has continuously shifted the coastline westwards thus along with the delta progradation new harbour sites had to be established in a western direction historical sources refer to different harbours while much is known about the roman and older ones the exact location of the ports and the coastline in late roman and byzantine times is still an open question this article presents the results of geoarchaeological research in the area located along the southern flank of the kucuk menderes graben near ephesus sediments from cores were examined with geochemical sedimentological and microfaunal analyses these data were combined with the study of ancient maps and satellite images the chronological framework was rendered by ams 14 c ages and diagnostic ceramics the farthermost inland shoreline dates from 5000 bc since then delta progradation has continuously shifted the shoreline westwards canakgol today a little lake to the west of the city of ephesus is identified as the harbour site in late roman and byzantine times this harbour persisted at least until the 16th century ad further a landing site with a pier was discovered west of canakgol presumably dating to the late byzantine ottoman times

the evolution of an asymmetric deltaic lobe sf gheorghe danube in association with cyclic development of the river mouth bar long term pattern and present adaptations to human induced sediment depletion abstract the asymmetric sf gheorghe lobe is the only active lobe in the danube delta associated with a river mouth bar and related barrier islands and spits that has continuously displayed cyclic development during the last 1500 years during the early cycles the sf gheorghe distributary experienced a significant increase in sediment load by an order of magnitude as a result of the successive avulsions occurred 1 5 1 2 ka which redistributed more water and sediment captured from the neighboring branches of impu ita southern distributary of the sulina arm and dunav morphological and sedimentological analyses together with a newly obtained chronology throw light on the multiple ridgeset 10 structure of sf gheorghe lobe each of them excepting the first one following a common evolutionary pattern reflected by the cyclic succession of the recurring stages i subaqueous mouth bar building ii barrier island emergence and iii transformation into a barrier spit with several secondary spits the spits become encased into the muddy deltaic plain as narrow sandy ridges building out on the downdrift side of the lobe as a barrier marsh plain whereas the updrift side constantly accreted fed by longshore currents forming a classic beach ridge plain the size of each ridgeset increased exponentially with every new cycle due to the constant lengthening of the coastline as the downdrift side of the lobe advanced seaward through a series of progressively larger similar quadrilaterals yielding a corresponding geometric progression of the delta front size even though each newly formed ridgeset cycle had a longer lifespan the latest cycles lasting 4 5 times longer than the first ones 200 440 years versus 50 80 years the evolutionary model remained unchanged as long as the balance between wave and river borne sediments defined by the sedimentary index si remained constantly low si 0 1 whereas the mean advance rates of the river mouth remained constant at c 10 m year abrupt changes occurred within the last cycle since the beginning of the 20th century as a consequence of human induced depletion of sediment supplied by the danube flow and is mainly expressed by the complete cessation of the updrift coastal progradation and the prevalence of erosion in front of the river mouth these changes which engendered a threefold increase of the si 0 37 at present are reflected by the recent 1930s present river mouth dynamics characterized by cessation of its long term seaward expansion in favor of downdrift migration this is indicative of the transition of the sf gheorghe mouth from an asymmetric to a deflected wave influenced delta morphology whose current developments mark a significant change in the multicentennial cyclic evolutionary pattern the asymmetric to deflected transition reflects the net increase in the influence of wave driven sediment circulation on river mouth morphology corresponding to a critical si threshold of ca 0 2 0 2 asymmetric 0 2 deflected