biostratigraphy and sedimentology of the fluviatile untere serie early and middle miocene in the central part of the north alpine foreland basin implications for palaeoenvironment and climate the early to middle miocene fluviatile untere serie lithostratigraphic unit of the upper freshwater molasse ufm in the north alpine foreland basin nafb crops out in a 40 m long section at untereichen altenstadt central part of the nafb this section yields a unique superposition of two vertebrate assemblages belonging to different biostratigraphic units early part osm c d karpatian and osm e early badenian detailed taxonomic analyses reveal different diversity patterns in the two assemblages nine small mammal and six ectothermic vertebrate taxa occur in the older level ua 540 m while 20 small mammal and 23 ectothermic vertebrate taxa are recorded for the younger level ua 565 m from the latter locality comes a small sized representative of the biostratigraphically significant megacricetodon lappi lineage this evolutionary level has not been documented previously for the eastern part of the nafb bioclimatic analysis combined with lithofacies and architectural element analysis indicates that significant changes in the fluvial sedimentation style surface water runoff and tectonics occurred between the early karpatian and early badenian a meandering fluvial system marly unit is erosively overlain by sandy braided river deposits sandy unit overbank deposits of the marly unit revealed that the older vertebrate fossil assemblage ua 540 m is deposited in an animal burrow that was presumably produced by owls both reptilian and mammalian taxa are indicative of a relatively open environment and dry probably semi arid climate conversely vertebrates from the sandy unit ua 565 m which are accumulated in channel fill deposits suggest closed as well as open habitats with a subtropical humid climate and mean annual rainfall of about 1 000 mm according to the sequence stratigraphic analysis the marly unit is interpreted as a highstand system tract of the tb 2 2 global 3rd order sequence the new results add support to the hypothesis that the erosional unconformity between both sedimentary units spanning the karpatian badenian transition corresponds to the pre riesian hiatus which has been interpreted as part of the styrian tectonic phase and was previously identified only in the eastern and northeastern part of the nafb the biostratigraphic data further indicate that this hiatus lasted longer in the eastern than in the central part of the basin

messinian lago mare deposits near the strait of gibraltar malaga basin s spain a new stratigraphic unit named lm unit located at the base of the pliocene marine succession in the eastern sector of the malaga basin has been distinguished this unit is composed of two fining upward sequences bounded by a discontinuity related to synsedimentary tectonic activity both sequences are made up of basal alluvial deposits overlain by subaquatic deposits the lower sequence contains rich mollusc faunas characterized by bivalves lymnocardiinae and dreissenidae of paratethyan origin and non marine gastropods typical of oligo low mesohaline shallow waters and low diversified ostracod faunas of paratethyan origin loxocorniculina djafarovi tyrrhenocythere pontica euxinocythere maeotocythere praebaquana and amnicythere propinqua typical of low mesohaline waters alternances of monospecific ostracod assemblages made of cyprideis agrigentina or oligotypic assemblages made of c agrigentina and loxoconcha spp and richer assemblages made of l djafarovi accompanied by several amnicythere spp and camptocypria sp 1 characterize the upper sequence pointing to more unstable environment affected by salinity and depth changes some samples collected from this upper sequence yielded rare planktonic and benthic foraminifera which could suggest the sporadic establishment of quasi normal marine conditions in the westernmost mediterranean during the deposition of this sequence the palaeontological data and the palaeomagnetic results obtained in both the lm unit and the overlying pliocene marine sediments restrict the age of the former to the post evaporitic late messinian the age and the environmental conditions correlate these deposits with the lago mare event occurring throughout the mediterranean before the quick and widespread marine flooding of the mediterranean at the beginning of the pliocene

late miocene to pliocene palaeogeography of the paratethys and its relation to the mediterranean abstract the palaeogeographic evolution of the paratethyan and mediterranean realms are reconstructed with three maps ranging from the late miocene to the middle late pliocene the maps are based on the facial analysis of selected deposits clastic input slope slide process analyses as well as biogeographic data of the planktic benthic and terrestrial biota characteristic fossil assemblages are used for palaeobathymetric and palaeohydrologic interpretations restoration of palaeogeographic connections the palaeogeographic reconstructions are palinspastically restored after dercourt j ricou l e vrielynck b eds 1993 atlas tethys palaeoenvironmental maps gauthier villars paris pp 1 307 14 maps the paleogeographic atlas of northern eurasia 1997 inst tectonics lithospheric plates moscow 26 maps with modifications maps have been prepared for the terminal tortonian early messinian late pannonian early maeotian late messinian pontian salinity crisis time and piacenzian gelasian akchagilian they illustrate the neogene palaeogeographic evolution during and after the attic orogenesis though the emerging mountain system of the alpine foldbelt increasingly separated the paratethys from the mediterranean tethys paratethys connections remained extant and sufficiently effective for limited communication between both basins they governed many features of the cyclic depositional history and biogeographic evolution of the eastern paratethys

direct evidence for an ekman balance in the california current moored acoustic doppler current profiler velocity estimates and buoy wind observations made during a period of moderate southward winds were used to test the ekman balance at a site in the california current as in prior studies the wind driven flow was separated from the total flow by subtraction of a deep reference current the wind driven flow was shown to be in an ekman balance on daily timescales over a period of several months the mean observed transport was to the right of the wind and agreed to within 3 in magnitude and 4 in phase with the predicted ekman transport although the error bar was about 20 the mean velocity profile was a smooth spiral qualitatively similar although flatter than the theoretical ekman spiral prom the observed mean momentum balance profiles of the turbulent stress and eddy viscosity were inferred eddy viscosity estimates within the wind mixed layer were o 100 cm2 s 1

the randeck maar palaeoenvironment and habitat differentiation of a miocene lacustrine system abstract the randeck maar in s germany is a well known fossil lagerstatte with exceptionally preserved fossils particularly insects and plants which thrived in and around the maar lake during the mid miocene climatic optimum late early early middle miocene mammal zone mn5 we provide the first critical and detailed overview of the fauna and flora with lists of 363 previously published partially revised and newly identified taxa plant remains are the most diverse group 168 taxa followed by insects 79 the flora points towards subhumid sclerophyllous forests and mixed mesophytic forests the former being an indication for the occurrence of seasonal drought three main sections can be differentiated for the habitats of the randeck maar lake system 1 deep and open water lake habitats with local and short termed mass occurrences of insect larvae amphibians and or gastropods while fish is particularly scarce the interpretation of the water chemistry is problematic because contradictive palaeoenvironmental indicators for both brackish and freshwater conditions exist 2 shallow parts of the lake comprise a narrow reed belt with insects and gastropods living on the exposed plant stems as well as turtles 3 crater slopes and surrounding plateaus were mainly covered by subhumid sclerophyllous to mixed mesophytic forests depending on sun exposition and soil conditions horses and other forest dwellers preferably lived in forested habitats while proboscideans and rhinoceratids occupied more open habitats our study also brings up contradictive results that cannot be untangled with the current state of knowledge and thus directions for future studies are discussed

transport of atmospheric impurities over the qinghai xizang tibetan plateau as shown by snow chemistry abstract chemical records were recovered from samples collected from snow pits over two transects s n and se nw across the qinghai xizang tibetan plateau the records show that the flux of major ions in the regions to the north of mt tanggula is on the average 6 30 times higher than that of the regions to the south and 0 6 5 times higher than regions to the southeast it appears that mt tanggula provides a barrier to continental dust transported across the plateau from the north and to marine aerosols transported from the southeast the spatial patterns of snow chemistry as well as the total suspended particle tsp distribution along the northern qinghai xizang highway demonstrate that continental dust originates mainly from the deserts to the north while monsoon sources of moisture exert greater influence on snow chemistry on the southern part of the plateau seasonal variations of the major ions were also examined in a firn core drilled at a height of 7000 m on the dasuopu glacier and in a snow pit from the meikuang glacier eastern kunlun the choice of a high altitude site at dasuopu and the sampling season before snowmelt at meikuang avoided post depositional modification processes mainly the elution effect of meltwater thus guaranteeing the reliable recovery of the distribution of impurities in different seasons the peak of the impurities appear at dasuopu during the spring and at meikuang in the winter spring coinciding with the asian dust season however the amplitude of the seasonal variations at meikuang is much higher than at dasuopu ph values at the dongkemadi glacier are greater than 6 but at the dasuopu glacier himalayas they range between 4 and 7 5 the liquid conductivity lc from dongkemadi is positively correlated with the ph while at dasuopu lc is positively correlated with ph when ph is below 6 and negatively correlated with ph when it is greater than 6 this implies that during august to september the himalayan range is a transition zone between the transportation of continental dust and marine aerosols

recent climatic significance of chemical signals in a shallow firn core from an alpine glacier in the south asia monsoon region abstract there are 19 sub tropical temperate glaciers on mount yulong the southernmost currently glacier covered area in eurasia controlled by the south western monsoon climate in the summer of 1999 a firn core 10 10 m long extending down to glacier ice was recovered in the accumulation area of the largest glacier baishui no 1 periodic variations of climatic signals above 7 8 m depth were apparent and net accumulation of four years was identified by the annual oscillations of isotopic and ionic composition the boundaries of annual accumulation were confirmed by higher values of electrical conductivity and ph and by dirty refreezing ice layers at the levels of summer surfaces calculated mean annual net accumulation from 1994 95 to 1997 98 was about 900 mm water equivalent the amplitude of isotopic variations in the profile decreased with increasing depth and isotopic homogenization occurred below 7 8 m as a result of meltwater percolation variations of 18 o above 7 8 m showed an approximate correlation with the winter climatic trend at lijiang station 25 km away concentrations of ca 2 and mg 2 were much higher than those of na and k indicating that the air masses for precipitation were mainly from a continental source and that the core material accumulated during the winter period the close correspondence of cl and na indicated their common origin the decreasing trend of na cl ratios with increasing depth further reflects a progressive homogenization process caused by meltwater percolation concentrations of so 4 2 and no 3 in the core are quite low the mean annual net accumulation in the core and the estimated ablation indicate that the average annual precipitation above the glacier s equilibrium line is 2400 3100 mm but this needs to be confirmed by long term observation of mass balance

using borehole logging and electron backscatter diffraction to orient an ice core from upper fremont glacier wyoming usa while glacier fabric reflects the accumulated strain detailed azimuthal information is required to link the microstructure to the flow and this is not easily gathered at depth borehole logging provides a way to obtain a log of azimuthal orientation of tilted stratigraphic features that can be used to orient the core with respect to glacier flow we demonstrate this using acoustic borehole logs and the ice core from a 162 m borehole in upper fremont glacier wind river range wyoming usa we measured the dip of tilted dust and bubble layers in the actual ice core identified them on the borehole log then used their strike to orient the core sections containing them we examined the crystal orientation fabric of our samples using electron backscatter diffraction in a scanning electron microscope when we compared the orientation of the tilted layers in some samples with the fabric we found that the normal to the foliation and the c axes maxima both pointed in the direction of maximum shear stress this illustrates the usefulness of borehole logs for orienting ice cores after removal from the borehole and for developing a better understanding of fabric development

aspects of freshwater mollusc ecological biogeography abstract freshwater molluscs include a variety of groups derived independently from marine ancestry and varying in range of habitat reproduction and distribution the fossil record shows the great age of most families that likely differentiated in the paleozoic present day distributions of species and higher groups are rationalized as due to different ranges of habitat life history and means of dispersion with a strong historical component at the global level distribution of 42 principal families of freshwater and marginally marine molluscs is summarized most are widespread the others representing only a few types of distributiion groups characteristic of the southern continents tethyan or localized localized families are mostly prosobranchs and are concentrated in areas otherwise noted for endemism the atlantic and indo pacific oceans have vastly different relationss to the ranges of freshwater molluscs the atlantic cuts across genera and sets of genera as if it came into being after the evolution of those groups the pacific is not so crossed but bordered with primitive and local families as if development of the pacific basin were earlier and accompanied origin of living families of pulmonates the fossil record in north america is reviewed briefly already in the cretaceous a faunistic division is recognizable some groups in the west are related to those of east asia others in the east are of trans atlantic relationships withdrawal of the epeiric sea from the mid continent exposed what can be viewed as an enormous land bridge linking different faunistic regions these regions retain distinctiveness today no large scale faunal migrations have occurred supposed migrations to south american and australia are therefore dismissed freshwater mussels have often been employed in zoogeographic studies the region west of the rocky mountains in north america has a sparse fauna of asiatic affinities throughout all of cenozoic time these features have been characteristic emphasizing the hisorical value of mussel distribution the historical roots of some zoogeographic thoughts are traced back to charles lyell who introduced uniformitarianism in geology the principle that the distribution of different groups of freshwater molluscs is carried out in different ways determined by range of habitat and life history is uniformitarian it is based on the action of presently observable processes and on their result over long periods of time attention to details of modern ranges and recognition of polytypic and vicariant groups is in full keeping with lyell s urging patiently to explore the realities of the present lyell s belief in a center of origin of species captivated the mind of charles darwin believing in evolution he nevertheless was compelled to deal with geographic distribution in a lyellian non evolutionary way efforts to deal with animal geography by numbers of immigrants flying birds moving plates and floating rafts go back beyond darwin to lyell s special creation the uniformitarian interpretation of geographic distribution is linked causally to the uniformitarian approach of geology both are corollaries of a more general principle earth and life evolve together this also provides the premises for interpretations of the past

indian monsoon and north atlantic oscillation signals reflected by cl and na in a shallow ice core from dasuopu glacier xixabangma himalaya

association between atmospheric circulation patterns and firn ice core records from the inilchek glacierized area central tien shan asia 1 glacioclimatological research in the central tien shan was performed in the summers of 1998 and 1999 on the south inilchek glacier at 5100 5460 m a 14 36 m firn ice core and snow samples were collected and used for stratigraphic isotopic and chemical analyses the firn ice core and snow records were related to snow pit measurements at an event scale and to meteorological data and synoptic indices of atmospheric circulation at annual and seasonal scales linear relationships between the seasonal air temperature and seasonal isotopic composition in accumulated precipitation were established changes in the 18o air temperature relationship in major ion concentration and in the ratios between chemical species were used to identify different sources of moisture and investigate changes in atmospheric circulation patterns precipitation over the central tien shan is characterized by the lowest ionic content among the tien shan glaciers and indicates its mainly marine origin in seasons of minimum precipitation autumn and winter water vapor was derived from the arid and semiarid regions in central eurasia and contributed annual maximal solute content to snow accumulation in tien shan the lowest content of major ions was observed in spring and summer layers which represent maximum seasonal accumulation when moisture originates over the atlantic ocean and mediterranean and black seas

chemical composition of snow and ice from chhota shigri glacier central himalaya abstract a systematic study of the chemical composition of snow firn from a shallow core surface ice and of meltwater samples collected from the chhota shigri glacier central himalaya is reported here the average concentrations of na and cl in snow are 402 and 753 g l 1 respectively whereas those in old surface ice are relatively low 185 g l 1 and 375 g l 1 respectively the average cl na weight ratio in these samples is 1 9 quite similar to that in the sea salts suggesting that both cl and na are predominantly of marine origin the concentrations of other major ions such as k mg ca no3 and so4 in snow and ice samples are generally less than 1 mg l 1 the major ion concentrations when normalized to na indicate that the abundances of k and ca are dominated by terrestrial sources whereas mg appears to have both marine and terrestrial sources based on the seasonal variations of na and cl concentrations observed in the ice core samples an approximate accumulation rate at the core site has been estimated to be 1 6 m year 1 640 kg m 2 year 1

chemical composition of fresh snow from glaciar marinelli tierra del fuego chile a fresh snow sampling campaign was conducted during the late austral summer of 2006 in the accumulation zone of glaciar marinelli located in the cordillera darwin tierra del fuego chile snow samples were analyzed for stable isotopes d 18 o major soluble ions na k ca 2 mg 2 cl no3 so4 2 ms and major and trace elements na mg al fe ca sr cd cs ba la ce pr dy ho er bi u as ti v cr mn the dominance of marine chemistry resembles that in studies from patagonian glaciers snow chemistry was dominantly loaded by marine species cl na and ssso4 2 while contributions of crustal species e g al and fe were very low empirical orthogonal function analysis suggests two possible dust sources one represented by al and fe and the other by la ce and pr enrichment factor calculations suggest the majority of elements are within average upper crustal ratios but major enrichments of bi and cd hundreds of times suggest possible anthropogenic sources linear correlation ofd 18 o and barometric pressure r 0 60 p 0 007 suggests a potential amount effect relationship between depletedd 18 o ratios and stronger storm conditions e g greater precipitation the snow chemistry records from glaciar marinelli are the first measured in tierra del fuego the southernmost glaciated region outside antarctica

a preliminary assessment of the potential application of glaciochemical investigations on heard island south indian ocean on a utilise les analyses de fluorures chlorures sodium sulfates bromures nitrates et fer effectuees dans un carottage de neige dans heard island preleve a 2450 m en vue d evaluer les possibilites d etude glaciochimique les chlorures le sodium et les sulfates se sont montre de bons indicateurs de saison

neogene lake systems of central and south eastern europe faunal diversity gradients and interrelations abstract the gastropod diversity of 12 neogene lake systems is evaluated in total 1184 gastropod taxa from 119 localities are recorded deriving from the early miocene rzehakia lake system the early to middle miocene dinarid lake system lake skopje the paratethyan sarmatian lakes and the south german lakes the late miocene lake pannon the pliocene lakes dacia transylvania slavonia kosovo and sostanj as well as the holocene lake petea each lake system is characterised according to its faunistic inventory and endemism according to their gastropod faunas the lakes may be divided into pyrgulid hydrobiid viviparid and planorbid dominated ones the generally high endemism rate is between 60 and 98 species diversity and generic diversity are strongly correlated in contrast neither endemism nor lake size are tightly linked with diversity outstandingly high diversities such as observed for lake pannon are rather a result of the combined effect of autochthonous evolution in a long lived system and accumulation of inherited elements examples of parallel evolution in lymnaeids and planorbids are presented

paleobiogeography of scleractinian reef corals changing patterns during the oligocene miocene climatic transition in the mediterranean abstract during the oligocene miocene greenhouse to icehouse climatic transition the biogeography of reef corals or zooxanthellate like scleractinian corals was gradually changing from a pan tropical tethyan province in the eocene to three reef coral provinces of the western atlantic caribbean indo pacific and mediterranean our reefcoral database encompasses updated and homogenized data on paleoenvironmental and systematics of scleractinian corals occurring in the oligocene and miocene outcrops from circum mediterranean regions provided by most of relatively recently published data in the literature and by the study of published and unpublished collections of coral specimens from the same area including the important collections housed at the mnhn paris and our own collections as there is no validated direct criterion for the identification of the coral zooxanthellate symbiosis in the fossil record and considering the difficulty to use the biogeochemical approaches in the context of this study the subjectivity of the morphological criteria and the relative recent age of the fossil corals we are dealing with a uniformitarian approach has been used for inferring the symbiotic status of scleractinian genera in reefcoral among the 158 genera included in our database 93 can be considered as zooxanthellate and 10 have a doubtful zooxanthellate status this relatively exhaustive database was used to reconstruct the temporal and spatial distribution of scleractinian corals in the mediterranean during the oligocene miocene time in order to discuss the interplaying effects of the global cooling at that time the re organization of the tethyan realm resulting from the african arabian and eurasian plate collision and the emergence of the alpine chains driving the gradual northward movement of the whole region outside the tropical subtropical belt it is shown that the structure of the mediterranean z coral oligocene miocene paleobiodiversity was characterized by many geographically restricted genera with a moderate to short stratigraphical range and a few long ranging widespread genera a major consequence of this structure is that the extinction pattern has proceeded through the preferential extinction of rare occurrence genera through time the potential rapid long distance dispersal of most coral larvae compared to the size of the oligocene miocene mediterranean explains why no biogeographical subprovinces can be distinguished for the z coral fauna on a local scale ecological processes tend to sort coral taxa by limiting z coral development to geographically restricted and discontinuous areas this accounts for the large amount of geographically restricted taxa forming the mediterranean coral fauna the interaction of plate tectonics alpine orogenesis and climate at local to subregional scales exerts strong controls over the spatio temporal distribution of z coral assemblages within the circum mediterranean realm in particular we suggest that the richness and composition of the eastern atlantic coral fauna are indirectly related to the opening and closure of the eastern seaway connection with the indian ocean which controlled the e w circulation of surface waters and hence the westwards dispersal of pelagic larvae at the scale of the whole region the gradual regional climatic change produced by the northwards migration of the entire area superimposed on the global cooling appears in large part responsible for the extinction pattern of z corals through time in the mediterranean biogeographical province

examination of selected microparticles from the sentik glacier core ladakh himalaya india analyse par microscopie electronique et spectrometrie atomique rx dispersive des quatre groupes morphologiques des microparticules de l himalaya aplaties anguleuses biogeniques et anormales

atmospheric soluble dust records from a tibetan ice core possible climate proxies and teleconnection with the pacific decadal oscillation record 1935 2005 statistical analysis of major ion time series suggests that atmospheric soluble dust species dominate the chemical signature and that background dust levels conceal marine ion species deposition the soluble dust time series have interspecies relations and common structure empirical orthogonal function eof 1 suggesting a similar soluble dust source or transport route annual and seasonal correlations between the eof 1 time series and national centers for environmental prediction national center for atmospheric research reanalysis climate variables 1948 2004 suggest that the mt geladaindong ice core record provides a proxy for local and regional surface pressure an approximately threefold decrease of soluble dust concentrations in the middle to late 1970s accompanied by regional increases in pressure and temperature and decreases in wind velocity coincides with the major 1976 1977 shift of the pacific decadal oscillation pdo from a negative to a positive state this is the first ice core evidence of a potential teleconnection between central asian atmospheric soluble dust loading and the pdo analysis of temporally longer ice cores from mt geladaindong may enhance understanding of the relationship between the pdo and central asian atmospheric circulation and subsequent atmospheric soluble dust loading

a review of central asian glaciochemical data the glaciers of central asia provide suitable locations from which to recover continuous high resolution glaciochemical records on a continental scale although the glaciochemical investigations undertaken to date in central asia are few in number and limited in terms of spatial coverage and length of record some preliminary observations can be made concerning regional and seasonal trends in snow chemistry in this region the sodium chloride ratio for most snow samples collected in central asia approaches the ratio found in sea water 0 86 in leq kg i reflecting a marine source for these constituents sodium and chloride concentrations are on average 3 10 times higher in the himalayas than in the karakoram demonstrating the greater influence of monsoonal sources of moisture in the himalayas very high sodium concentrations from khel khod glacier probably reflect a local crustal source from surrounding ice free areas low nitrate concentrations were found in snow collected from the southern margin of the himalayas and high concentrations in snow deposited on the north margin of the himalayas this strong regional trend in the spatial distribution of nitrate suggests the influx of continental aerosols rich in nitrate originating from the arid regions of central asia high calcium concentrations measured in snow from mount everest and the north west corner of china are also indicative of dust derived from the arid regions of central asia very high sulfate concentrations found in snow from the tien shan and the bogda shan most likely reflect local anthropogenic sources the altitude effect on isotopic composition is not apparent from snow samples collected in central asia understanding the processes which control the chemical content of snow the local to regiona l scale complexities

a gastropod based biogeographic scheme for the european neogene freshwater systems abstract for the first time a palaeobiogeographic framework is proposed for european neogene freshwater systems the distribution of 2226 species group taxa of freshwater gastropods from over 2700 miocene and pliocene localities was evaluated the localities were grouped into palaeo freshwater systems based on latest palaeogeographic reconstructions cluster analyses were computed for four time slices i e early miocene middle miocene late miocene and pliocene the analyses demonstrate a generally high degree of provincialism for the neogene freshwater systems and allow the definition of biogeographic units the delimitations are based on the cluster analyses the degree of endemicity and geographical coherence the early miocene is characterised by a relatively low degree of provincialism suggesting the distinction of three regions coinciding with the development of many endemic systems on the dinarian anatolian island and in central europe the middle miocene demonstrates a higher degree of provincialism allowing the definition of six biogeographic regions with the onset of the late miocene the retreat of the central paratethys and development of the huge lake pannon massively shaped faunal evolution and palaeobiogeography in general the formation of the lago mare environment fringing the mediterranean basin as well as the development of several restricted freshwater systems in western europe additionally promoted biogeographic division the increasing provincialism allowed the delimitation of six biogeographic regions three of which could be subdivided into seven dominions with the disappearance of lake pannon and the decline of western european and mediterranean faunas at the miocene pliocene boundary biodiversity hotspots shifted towards eastern and southeastern europe for the pliocene four biogeographic regions five dominions and four provinces were defined most of the here proposed biogeographic units and faunal differences are governed by the varied existence of large long lived systems because of their prolonged duration they immensely influenced the community composition on the family level differences of the relative species richnesses per biogeographic region and the rising rate of endemicity the underlying mechanism for this pattern is the ongoing continentalization of europe triggered by the alpidic orogenesis and the simultaneous retreat of the paratethys sea the continuing restriction of this huge intracontinental sea from the mediterranean promoted the evolution of endemic freshwater faunas the arising long lived systems like lake pannon lake dacia or lake slavonia persisted over several millions of years and stimulated the evolution of highly diverse and endemic faunas

paleogeographic evolution of the late miocene lake pannon in central europe abstract the paleogeographic evolution of lake pannon within the pannonian basin is reconstructed with eight maps ranging from the middle miocene to the early pliocene the maps are based on the distribution of selected biozones and specific fossils and on complementary sedimentological and seismic information our reconstruction shows that the history of lake pannon can be divided into three distinct intervals an initial stage with low water level which resulted in isolation from the sea at about 12 ma and might have led to temporary fragmentation of the lake an interval of gradual transgression lasting until ca 9 5 ma and a long late interval of shrinkage and infilling of sediments that persisted into the early pliocene the deep subbasins of the lake formed during the transgressive interval in more basinward locations than the deep basins of the preceding sarmatian age the southern shoreline running parallel with the sava and danube rivers along the northern foot of the dinarides changed very little during the lifetime of the lake while the northern shoreline underwent profound changes

interpretation of the chemical and physical time series retrieved from sentik glacier ladakh himalaya india analyse a partir de mesures de la radioactivite d analyses chimiques chlorures sodium fer silicates phosphates ammonium d 18 o et ph et de donnees physiques des variations cycliques temporelles des glaciers application aux paleoclimats

monsoon and dust signals recorded in dasuopu glacier tibetan plateau during summer 1997 a 15 m firn core was recovered from dasuopu glacier 28 23 n 85 44 e 7000 m a s l on the northwest margin of xixabarngma feng in the central himalaya oxygen isotope values and concentrations of ca 2 mg 2 nh 4 so 4 2 and no 3 were measured over the 10 years of snow accumulation captured in the firn core the seasonal variations of 18 o values and major ion concentrations in the dasuopu core indicate that summer monsoon and dust signals are clearly recorded in dasuopu glacier annual variations in 18 o values are controlled by the amount effect with more negative i e lighter 18 o values representing summer monsoon precipitation characteristic of tropical regions higher concentrations of ca 2 mg 2 and so 4 2 reflect the influx of mineral aerosols from the vast arid and semi arid desert regions to the north and west during the spring dust storm period high spring concentrations of nh 4 and no 3 appear to reflect changes in regional biogenic source strength

eocene pliocene time scale and stratigraphy of the upper rhine graben urg and the swiss molasse basin smb we present a general stratigraphic synthesis for the upper rhine graben urg and the swiss molasse basin smb from eocene to pliocene times the stratigraphic data were compiled both from literature and from research carried out by the authors during the past 6 years an index of the stratigraphically most important localitites is provided we distinguish 14 geographical areas from the helvetic domain in the south to the hanau basin in the north for each geographical area we give a synthesis of the biostratigraphy lithofacies and chronostratigraphic ranges the relationships between this stratigraphic record and the global sea level changes are generally disturbed by the geodynamic e g subsidence evolution of the basins however global sea level changes probably affected the dynamic of transgression regression in the urg e g middle pechelbronn beds and serie grise corresponding with sea level rise between ru1 ru2 and ru2 ru3 sequences respectively as well as in the molasse basin regression of the umm corresponding with the sea level drop at the ch1 sequence the urgent project upper rhine graben evolution and neotectonics provided an unique opportunity to carry out and present this synthesis discussions with scientists addressing sedimentology tectonics geophysics and geochemistry permitted the comparison of the sedimentary history and stratigraphy of the basin with processes controlling its geodynamic evolution data presented here back up the palaeogeographic reconstructions presented in a companion paper by the same authors see berger et al in int j earth sci 2005

extension and compression related basins in central italy during the messinian lago mare event abstract during the messinian lago mare event in the central mediterranean area compression and extension related basins developed as a consequence of the post tortonian evolution of the tyrrhenian apennines system all these syn tectonic sedimentary basins were characterized by different subsidence rates and sedimentary processes several sections located in different tectonic domains from the tyrrhenian to the adriatic margin of the apennine chain have been investigated s valentino in abruzzo citeriore roccamorice penscosansonesco roccacaramanico and le vicenne sections are located in compression related basins foreland basin system while the tolfa blera sections and the sedimentary succession of mondragone 1 well drilled in the garigliano coastal plain are located in extension related basins hinterland or back arc basins the recognition of ostracod assemblages with paratethyan affinities allows them to be referred to the messinian lago mare event loxoconcha djaffarovi zone this result allows us to consider the tyrrhenian rifting the accretion of the apennine thrust belt and the increase in subsidence rate during the flexuration of the foreland domain as synchronous processes due to the same geodynamical process taking into account the thicknesses of the analysed sedimentary basins different total subsidence rates have been computed for both the compression and extension related basins the syn rift basins that developed on the eastern margin of the northern tyrrhenian basin volterra val di fine and tolfa blera basins recorded a mean total subsidence rate of 1 25 mm a whereas higher subsidence rates affected the eastern margin of the central tyrrhenian basin 5 mm a garigliano coastal plain the differences in horizontal stretching and total subsidence rates that affected the tyrrhenian extensional area correspond to different migration rates of the apennine orogenic system in the northern 10 mm a and central apennines 40 mm a this difference in the total syn rift subsidence rate fits in well with the segmentation model of the tyrrhenian apennines system along a nne ssw lithosphere discontinuity which crosses the system from ancona northern apennines to the r selli lineament in the tyrrhenian basin

mare versus lago mare marine fishes and the mediterranean environment at the end of the messinian salinity crisis during the late messinian c 5 5 ma ago after evaporitic sedimentation and before the pliocene flooding the mediterranean recorded a major environmental change testified by deposition of non marine sediments of the so called lago mare facies such deposits are widespread in the mediterranean basin usually characterized by molluscs and ostracodes of brackish affinity here we present marine fish remains from lago mare deposits of central italy the fossils represented by both articulated skeletons and otoliths were collected from nine stratigraphic horizons of the upper portion of the lago mare sequence of cava serredi tuscany marine euryhaline fishes strongly dominate the assemblages but fully marine stenohaline fishes belonging to the families myctophidae and bythitidae are also present the fossil fish remains are associated with classic lago mare ostracodes and molluscs these fossil fishes clearly demonstrate that normal marine conditions were present at least during the upper interval of the lago mare event implying that the marine refilling of the mediterranean was intra messinian rather early pliocene we argue in favour of the necessity of a new palaeoenvironmental interpretation for the post evaporitic messinian of the mediterranean

chronology causes and progression of the messinian salinity crisis the messinian salinity crisis is widely regarded as one of the most dramatic episodes of oceanic change of the past 20 or so million years 1 3 earliest explanations were that extremely thick evaporites were deposited in a deep and desiccated mediterranean basin that had been repeatedly isolated from the atlantic ocean1 2 but elucidation of the causes of the isolation whether driven largely by glacio eustatic or tectonic processes have been hampered by the absence of an accurate time frame here we present an astronomically calibrated chronology for the mediterranean messinian age based on an integrated high resolution stratigraphy and tuning of sedimentary cycle patterns to variations in the earth s orbital parameters we show that the onset of the messinian salinity crisis is synchronous over the entire mediterranean basin dated at 5 96 0 02 million years ago isolation from the atlantic ocean was established between 5 59 and 5 33 million years ago causing a large fall in mediterranean water level followed by erosion 5 59 5 50 million years ago and deposition 5 50 5 33 million years ago of non marine sediments in a large lago mare lake sea basin cyclic evaporite deposition is almost entirely related to circum mediterranean climate changes driven by changes in the earth s precession and not to obliquity induced glacio eustatic sea level changes we argue in favour of a dominantly tectonic origin for the messinian salinity crisis although its exact timing may well have been controlled by the 400 kyr component of the earth s eccentricity cycle

evolution of the freshwater ecosystem the fossil record abstract the freshwater ecosystem may be as old as most life although freshwater life is taxonomically impoverished in comparison with marine and terrestrial biotas and ultimately derived from them it cannot be assumed that freshwater communities have necessarily been less complex in the geologic past than they are today although it is clear they have undergone a number of major changes freshwaters contain not only their own ancient and peculiar groups some with ancestries as far back as the middle paleozoic but they have been a theater for adaptive radiation of more recent immigrants from the land or sea and a way station for still other groups that passed through both from sea to land and the reverse this review summarizes first fossil records in freshwaters for many of these organisms and examines the question of the changing complexity of the freshwater ecosystem through time by looking at the fossil record of continental aquatic habitats

paleogeographic evolution of the southern pannonian basin 40ar 39ar age constraints on the miocene continental series of northern croatia the pannonian basin originating during the early miocene is a large extensional basin incorporated between alpine carpathian and dinaride fold thrust belts back arc extensional tectonics triggered deposition of up to 500 m thick continental fluvio lacustrine deposits distributed in numerous sub basins of the southern pannonian basin extensive andesitic and dacitic volcanism accompanied the syn rift deposition and caused a number of pyroclastic intercalations here we analyze two volcanic ash layers located at the base and top of the continental series the lowermost ash from mt kalnik yielded an 40ar 39ar age of 18 07 0 07 ma this indicates that the marine continental transition in the slovenia zagorje basin coinciding with the onset of rifting tectonics in the southern pannonian basin occurs roughly at the eggenburgian ottnangian boundary of the regional paratethys time scale this age proves the synchronicity of initial rifting in the southern pannonian basin with the beginning of sedimentation in the dinaride lake system beside geodynamic evolution the two regions also share a biotic evolutionary history both belong to the same ecoregion which we designate here as the illyrian bioprovince the youngest volcanic ash level is sampled at the glina and karlovac sub depressions and both sites yield the same 40ar 39ar age of 15 91 0 06 and 16 03 0 06 ma respectively this indicates that lacustrine sedimentation in the southern pannonian basin continued at least until the earliest badenian the present results provide not only important bench marks on duration of initial synrift in the pannonian basin system but also deliver substantial backbone data for paleogeographic reconstructions in central and southeastern europe around the early middle miocene transition

catastrophic flood of the mediterranean after the messinian salinity crisis around 5 6 million years ago the mediterranean sea became disconnected from the world s oceans and during the period that followed known as the messinian salinity crisis sea levels fell dramatically as the waters evaporated the water returned about 5 3 million years ago but the details about this the largest known flood in earth s history remain sketchy a study making use of boreholes seismic data and numerical modelling suggests that it was a catastrophic event though it started as a trickle that may have lasted several thousand years as much as 90 of the incoming water was transferred in less than two years such an abrupt flood may have involved peak rates of sea level rise of more than 10 metres a day 5 33 million years ago in an event known as the zanclean flood atlantic waters refilled a mostly desiccated mediterranean sea which had become disconnected from the world s oceans however the nature abruptness and evolution of this flood remain poorly constrained using borehole and seismic data and a model study it is now suggested that 90 per cent of the water was transferred in a short period of a few months to two years with peak rates of sea level rise in the mediterranean possibly reaching more than 10 metres per day the mediterranean sea became disconnected from the world s oceans and mostly desiccated by evaporation about 5 6 million years ago during the messinian salinity crisis1 2 3 the atlantic waters found a way through the present gibraltar strait and rapidly refilled the mediterranean 5 33 million years ago in an event known as the zanclean flood4 the nature abruptness and evolution of this flood remain poorly constrained4 5 6 borehole and seismic data show incisions over 250 m deep on both sides of the gibraltar strait that have previously been attributed to fluvial erosion during the desiccation4 7 here we show the continuity of this 200 km long channel across the strait and explain its morphology as the result of erosion by the flooding waters adopting an incision model validated in mountain rivers this model in turn allows us to estimate the duration of the flood although the available data are limited our findings suggest that the feedback between water flow and incision in the early stages of flooding imply discharges of about 108 m3 s 1 three orders of magnitude larger than the present amazon river and incision rates above 0 4 m per day although the flood started at low water discharges that may have lasted for up to several thousand years our results suggest that 90 per cent of the water was transferred in a short period ranging from a few months to two years this extremely abrupt flood may have involved peak rates of sea level rise in the mediterranean of more than ten metres per day

messinian salinity crisis regulated by competing tectonics and erosion at the gibraltar arc the persistent shallow connection between the atlantic ocean and the mediterranean sea that caused the messinian salinity crisis may have been sustained by a balance between tectonic uplift and erosion due to inflow about six million years ago a series of geological factors drastically reduced the exchange of water between the atlantic ocean to the mediterranean sea through what is now the strait of gibraltar the resulting widespread salt precipitation in the mediterranean linked to a decrease in sea level of about 1 5 kilometres due to evaporation is known as the messinian salinity crisis the exact mechanism that caused the crisis remains uncertain here daniel garcia castellanos and antonio villasenor propose a competition between the obstruction of the gibraltar arc seaway by tectonic uplift and its erosional deepening by water inflow controlled by the resulting changes in sea level difference across the gibraltar arc as a possible mechanism for the crisis the messinian salinity crisis1 2 5 96 to 5 33 million years ago was caused by reduced water inflow from the atlantic ocean to the mediterranean sea resulting in widespread salt precipitation and a decrease in mediterranean sea level of about 1 5 kilometres due to evaporation3 the reduced connectivity between the atlantic and the mediterranean at the time of the salinity crisis is thought to have resulted from tectonic uplift of the gibraltar arc seaway and global sea level changes both of which control the inflow of water required to compensate for the hydrological deficit of the mediterranean1 4 however the different timescales on which tectonic uplift and changes in sea level occur are difficult to reconcile with the long duration of the shallow connection between the mediterranean and the atlantic5 needed to explain the large amount of salt precipitated here we use numerical modelling to show that seaway erosion caused by the atlantic inflow could sustain such a shallow connection between the atlantic and the mediterranean by counteracting tectonic uplift the erosion and uplift rates required are consistent with previous mountain erosion studies with the present altitude of marine sediments in the gibraltar arc6 7 and with geodynamic models suggesting a lithospheric slab tear underneath the region8 9 10 the moderate mediterranean sea level drawdown during the early stages of the messinian salinity crisis3 5 can be explained by an uplift of a few millimetres per year counteracted by similar rates of erosion due to atlantic inflow our findings suggest that the competition between uplift and erosion can result in harmonic coupling between erosion and the mediterranean sea level providing an alternative mechanism for the cyclicity observed in early salt precipitation deposits and calling into question previous ideas regarding the timing of the events that occurred during the messinian salinity crisis1

major element rare earth element and sulfur isotopic composition of a high elevation firn core sources and transport of mineral dust in central asia 1 the arid region extending from the caspian sea into china contains some of the most extensive dust aerosol production areas in the world major element al fe ca and s rare earth element ree and isotopic 34s and 18o data from a 14 4 m long firn core recovered on the inilchek glacier tien shan mountains kyrgyzstan 5100 m elevation are presented and used to investigate the composition sources and transport of mineral dust to this central asian site the combination of geochemical compositions points to three distinct types of mineral deposits loess calcium carbonate and gypsum which do not covary in a linear fashion during the period recorded in the firn core 1992 1998 loess identified by its ree composition is characterized by distinct large scale deposition events and by ubiquitous background deposition at other times significant interannual scale variability is evident with the two largest loess events occurring within a single accumulation year 1997 and background conditions prevailing during 1994 1996 ree compositions specifically nd yb ratios point to multiple sources and transport directions of loess to inilchek glacier nonloess sources provide a significant fraction of the total ca and s deposited at the inilchek glacier hence the downcore profiles of ca and s reflect variability in the deposition of calcium carbonate and gypsum differences in the sulfur isotopic composition 34s of high dust period 15 0 and low background dust period 5 4 samples provide strong evidence for two sources of sulfate the former isotopic composition reflects a marine evaporite source of which there are many to the west of the tien shan mountains the latter composition indicates that a major portion of the atmospheric so42 was derived from anthropogenic emissions while the deposition of non loess ca calcite and non loess s gypsum is also high during the periods of high loess deposition there is pronounced ca and s variability during background loess periods 1994 1996 we suggest that the observed geochemical variability in the firn core can be explained by changes in local to regional scale atmospheric circulation and associated transport from multiple dust sources western kyrgyzstan kazakhstan versus the taklimakan desert china

magnetic measurements of greenland and himalayan ice core samples this paper summarizes isothermal remanence irm300mt measurements from holocene ice core samples from two contrasting glaciological regimes i the greenland ice sheet and ii a himalayan glacier cores had been previously characterized in terms of chronologies geochemistry and for the himalayan core microparticle concentrations six samples from the greenland 20 d ice core from the time period ad 1876 1983 did not yield magnetic measurements above instrumental noise level significant isothermal remanence measurements irm300mt were obtained from some levels in the himalayan ice core scanning electron microscopy and edax analyses indicate weathered crustal material the techniques used require ice core samples with relatively high dust loadings and or larger volume ice samples

rise and fall of the paratethys sea during the messinian salinity crisis abstract extremely thick evaporite units were deposited during the so called messinian salinity crisis msc 5 96 5 33 ma in a deep mediterranean basin that was progressively disconnected from the atlantic ocean a crucial but still poorly understood component in messinian evaporite models is the connectivity between mediterranean and paratethys i e the former black sea domain inadequate stratigraphic correlations and insufficient age control for paratethys sediments have so far hampered a thorough understanding of hydrological fluxes and paleoenvironmental changes here we present a new chronology for the eastern paratethys by integrating biostratigraphic and paleomagnetic data from mio pliocene sedimentary successions of romania and russia we show that a major flooding event from the mediterranean surged the paratethys basins at the maeotian pontian boundary 6 04 million years ago this indicates that sea level in both mediterranean and paratethys was high at the beginning of the msc we argue in favor of changes in paratethys mediterranean connectivity to initiate the msc in combination with elusive tectonic processes in the gibraltar arc a subsequent fall of paratethyan water level closely coincides to the mediterranean isolation event corresponding in age to the glacial cycles tg12 14 5 60 5 50 myr in the latest messinian a major climate change towards more humid conditions produced a positive hydrological balance and likely a transgression in the paratethys although our stratigraphic resolution cannot exclude a possible relation to the pliocene flooding of the mediterranean here

the glaciochemistry of snow pits from quelccaya ice cap peru 1982 we present glaciochemical data from a pilot study of two snow pits from quelccaya ice cap peruvian andes these are the first samples to be analyzed from quelccaya for nitrate and sulfate by ion chromatography ic for nitrate plus nitrite reactive silicate and reactive iron by colorimetry and for sodium by atomic absorption spectrophotometry the 3 m pits used in this study represent a one year record of mass accumulation and the 29 samples collected provide the first glaciochemical data from this area which can be compared with glaciochemical studies from other locations reactive iron reactive silicate and sodium and the profiles of 0 63 m microparticles from thompson and others 1984 are coincident suggesting that transport and deposition into this area of each species are controlled by similar processes the common source is probably local resulting from crustal weathering in general the reactive silicate values are lower than those observed in other alpine glacier ice the highest sulfate and nitrate values were observed in the upper few centimeters of the snow pit most of the sulfate concentrations were less than 3 m and are similar to values obtained for fresh surface snows from bolivia stallard and edmond 1981 since biological gaseous emissions are thought to be the major source of sulfur and nitrogen to the atmosphere over the amazon basin the sulfate and nitrate fluctuations may be due to seasonal biological input and or seasonal shifts in wind direction bringing material to quelccaya with only one exception the colorimetric nitrate plus nitrite data were higher than the ic nitrate data unfortunately the ic analyses were conducted 81 d after the colorimetric analyses the difference between the two data sets could be attributable to the following 1 the colorimetric technique may yield erroneously high results as suggested for polar ice by herron 1982 2 the ic technique yields erroneously low results due in part to the possible exclusion of nitrite concentrations and or 3 nitrite was lost via biological removal during the 81 d period before the ic analyses if the ic data are correct the mean nitrate value is 0 4 n 29 this value is similar to those reported from pre industrial aged polar ice herron 1982 if the colorimetric mean value 1 1 m is correct it is similar to colorimetrically determined values from other high elevation alpine ice lyons and mayewski 1983

a comparative study of fossil and extant algaenans using ruthenium tetroxide degradation in this study the chemical structure of algaenans isolated from the freshwater algae tetraedron minimum pediastrum boryanum and botryococcus braunii are compared with their fossil counterparts by means of ruo4 oxidation the results show that the algaenans investigated are preserved in sediments with only minor structural alterations however product mixtures from ruo4 degradation of the fossil algaenans exhibit a broader distribution of oxidation products than freshly isolated algaenans indicating that the fossil biopolymers contain a greater proportion of ether cross links which maybe an effect of diagenetic alteration or different algal strains despite these differences fossil algaenans can still be recognised chemically on the basis of the specific ruo4 oxidation products even after 50 ma of sediment burial

lago mare and the messinian salinity crisis evidence from the alboran sea s spain this paper provides a new environmental sedimentological and stratigraphic context of the lago mare deposits from the north alboran region and clarifies their chronologic location with respect to the messinian salinity crisis we present new micropaleontological data dinoflagellate cysts calcareous nannoplankton planktonic foraminifers correlated with field observations and offshore seismic interpretations we show that the lago mare event known in three onshore localities rio mendelin near malaga zorreras near sorbas gafares near nijar follows the marine reflooding of the mediterranean basin which ended the messinian salinity crisis chronologically these lago mare deposits last from the latest messinian to the early zanclean in fact the first influx of paratethyan organisms is revealed by the dinoflagellate cyst record from near malaga within a gilbert type fan delta overlying the messinian erosional surface invading molluscs and or ostracods may have persisted in lagoonal coastal areas more or less affected by discontinuous marine influxes sorbas and nijar the malaga area is convenient for a paleogeographic and sedimentary reconstruction which shows the prevalent forcing of sea level changes during the time interval 5 600 5 332 ma at the difference of the usually solicited prevalent tectonics the studied lago mare event is the third episode resulting in such a paleobiological assemblage in the mediterranean region and corresponds to the final two way water exchange at high sea level between the mediterranean and the former paratethys it documents the onset of the modern marine circulation in the mediterranean after the reflooding ending the messinian salinity crisis

holocene variations of monsoon rainfall in rajasthan two reconstructed histories of the monsoon rainfall in rajasthan show that the monsoon was weak or absent in latest glacial time with the advent of holocene climatic patterns fresh water lakes formed in dune fields and the pollen rain preserved in these reservoirs provides a basis for the reconstruction of the monsoon history the two reconstructions separated by only 150 km have some features in common and some striking differences both show maximum monsoon amounts in the early holocene with a roughly two thirds decrease to the present both show salinization in sub boreal time both show long intervals of near complete desiccation in the last four millennia the shorter term variations however are not closely parallel these shorter term variations may be explained in terms of the behavior of the present day interannual variability

circum mediterranean oligo miocene biogeographic evolution the gastropods point of view based on studies in iran qom basin esfahan sirjan basin zagros mountains in turkey mut and sivas basins in the mesohellenic basin and in northeastern egypt a new palaeobiogeographic concept for the oligocene and miocene in the circum mediterranean area with special emphasis on the distribution patterns of gastropod faunas is presented a very strict biogeographic terminology is proposed to avoid the common fusion of geographic faunistic and geodynamic terms in the palaeontologists jargon our main interest focuses on the affinities and the faunistic interactions between the early mediterranean and the early indo pacific regions during the oligo miocene especially the role of the early indo pacific faunas as the mythic centre of origination of early neogene european mollusc faunas as often vaguely indicated in the literature is critically evaluated this leads to the establishment of a mediterranean iranian province and a western indian eastern african province as palaeobiogeographic subunits of the western tethys region during the oligocene due to major geodynamic and related biogeographic changes in the early miocene the western tethys region no longer existed and was replaced by the proto mediterranean atlantic region for the area of the paratethys the palaeobiogeographic unit danubian province which includes the protocaspian subprovince is proposed furthermore the underrated transatlantic communication of the oligo miocene nearshore mollusc faunas is demonstrated altogether this paper is a contribution to the discussion on the biogeographic concepts classification and nomenclature in palaeontology as initiated by westermann palaeogeogr palaeoclimatol palaeobiogeogr 158 2000 1 13 163 2000 49 68 2002 elsevier science b v all rights reserved

late cenozoic increase in accumulation rates of terrestrial sediment how might climate change have affected erosion rates abstract accumulation rates of terrestrial sediment have increased in the past few million years both on and adjacent to continents although not everywhere apparently erosion has increased in elevated terrain regardless of when last tectonically active or what the present day climate in many regions sediment coarsened abruptly in late pliocene time sparser data suggest increased sedimentation rates at 15 ma approximately when oxygen isotopes in benthic foraminifera imply high latitude cooling if climate change effected accelerated erosion understanding how it did so remains the challenge some obvious candidates such as lowered sea level leading to erosion of continental shelves or increased glaciation account for increased sedimentation in some but not all areas perhaps stable climates that varied slowly allowed geomorphic processes to maintain a state of equilibrium with little erosion until 3 4 ma when large oscillations in climate with periods of 20 000 40 000 years developed and de

preliminary results from the chemical records of an 80 4 m ice core recovered from east rongbuk glacier qomolangma mount everest himalaya high resolution chemical records from an 80 4m ice core from the central himalaya demonstrate climatic and environmental changes since 1844 the chronological net accumulation series shows a sharp decrease from the mid 1950s which is coincident with the widely observed glacier retreat a negative correlation is found between the ice core 18o record and the monsoon precipitation for indian region 7 the temporal variation of the terrestrial ions ca2 and mg2 is controlled by both the monsoon precipitation for indian regions 3 7 and 8 located directly south and west of the himalaya and the dust storm duration and frequency in the northern arid regions such as the taklimakan desert china the nh4 profile is fairly flat until the 1940s then substantially increases until the end of the 1980s with a slight decrease during the 1990s which may reflect new agricultural practices the so4 2 and no3 profiles show an apparent increasing trend especially during the period 1940s 80s moreover so4 2 concentrations for the east rongbuk glacier core are roughly double that of the nearby dasuopu core at xixabangma himalaya due to local human activity including that of climbing teams who use gasoline for cooking energy and transport

the mid hungarian line a zone of repeated tectonic inversions abstract the mid hungarian line is a major tectonic feature of the intra carpathian area separating two terranes of different origin and tectonic structure although this tectonic line was known from borehole records it has not been described in seismic sections the study presents interpreted seismic lines crossing the supposed trace of the mid hungarian line these seismic sections show north dipping normal faults and thrust faults as well as cross cutting young strike slip faults a complex tectonic history is deduced including intra oligocene early miocene thrusting middle miocene extension local late miocene inversion and late miocene pliocene normal faulting and left lateral wrenching in the light of our seismic study we think that the best candidate for the mid hungarian line is a north dipping detachment fault beneath large masses of neogene volcanics the auxiliary structures to the north seen on seismic sections suggest that it moved as a south vergent thrust fault during the palaeogene early miocene which later was reactivated as a set of normal faults the northern alcapa unit overrode the southern tisza dacia unit along this fault zone the same relative positions are observed in the northern termination of the line other structures along the supposed trace of the line are north dipping normal or strike slip faults which frequently were reactivated as smaller thrust faults during the late neogene palaeogene early miocene thrusting along the line might be the result of the opposite tertiary rotations of the two major units as suggested by palaeomagnetic measurements and earlier models

spatial and seasonal variation of major ions in himalayan snow and ice a source consideration abstract the spatial and temporal variation of major ions ca2 mg2 na k nh 4 so 4 2 no 3 and cl in himalayan snow and ice is investigated by using two snow pits from the east rongbuk glacier 28 01 n 86 58 e 6500 m a s l one snow pit from the nangpai gosum glacier 28 03 n 86 39 e 5700 m a s l one snow pit from the gyabrag glacier 28 11 n 86 38 e 6303 m a s l and three ice cores from the sentik 35 59 n 75 58 e 4908 m a s l dasuopu 28 33 n 85 44 e 7000 m a s l and east rongbuk 27 59 n 86 55 e 6450 m a s l glaciers respectively in general the major ions show a significant seasonal variation with high concentrations during the non monsoon pre monsoon and post monsoon season and relatively low concentrations during the monsoon season monsoon precipitation with high local regional dust loading related to summer circulation is possibly responsible for the high concentrations occurring sporadically during the monsoon season the crest of the himalayas is an effective barrier to the spatial distribution of na cl and nh 4 concentrations but not to the major ions associated with dust influx e g ca2 and mg2 atmospheric backward trajectories from the hysplit 4 model used in identifying chemical species sourcing suggest that the major ions in the himalayan snow and ice come mainly from the thar desert located in the north india as well as west asia or even the distant sahara desert in the north africa during the winter and spring seasons this is different from the conventionally assumed arid and semi arid regions of the central asia factors such as different vapor sources due to atmospheric circulation patterns and geographical features e g altitude topography may contribute to the differences in major ionic concentrations between the western and eastern himalayas

new developments in the upper pliocene pleistocene stratigraphic units of the dacian basin eastern paratethys romania abstract as a result of multidisciplinary investigations carried out in the last two decades the knowledge of the pliocene and quaternary stratigraphy from dacian basin has increased considerably new lithostratigraphic units were revealed for example trajkovo fm romanian vl deni fm v n tori fm pleistocene and other units have been reassessed izvoarele fm tulucesti fm romanian a new biozonation based on molluscan fauna from the late pliocene nsm11 nsm12 and pleistocene qm1 qm9 deposits made possible a more accurate subdivision and cronostratigraphical assignments and correlations many localities with romanian mammal associations lupoaia dr nic podari tetoiu leu etc were reviewed adding new taxa in the faunal list with implications for accurately establishing host deposit ages these studies together with bio magnetostratigraphic investigations led to revision of the romanian stage boundaries and subdivisions pelendavian valahian and to outline several new pleistocene chronostratigraphic units the argedavian dinogetian ilfovian stages and milcovian uzunian netindavian musaisian substages finally one major achievement consisted in the pliocene pleistocene boundary relocation in the dacian basin in agreement with its new position at 2 6 ma in the mediterranean realm

on the formation and evolution of the pannonian basin constraints derived from the structure of the junction area between the carpathians and dinarides 1 the large number and distribution of rollback systems in mediterranean orogens infer the possibility of interacting extensional back arc deformation driven by different slabs the formation of the pannonian back arc basin is generally related to the rapid miocene rollback of a slab attached to the european continent a key area of the entire system that is neglected by kinematic studies is the connection between the south carpathians and dinarides in order to derive an evolutionary model we interpreted regional seismic lines traversing the entire serbian part of the pannonian basin the observed deformation is dominantly expressed by the formation of miocene extensional detachments and half grabens the extensional geometries and associated synkinematic sedimentation that migrated in time and space allow the definition of a continuous and essentially asymmetric early to late miocene extensional evolution this evolution was followed by the formation of few uplifted areas during the subsequent latest miocene quaternary inversion the present day extensional geometry changing the strike across the basin is an effect of the clockwise rotation of the south carpathians and apuseni mountains in respect to the dinarides our study infers that the carpathian rollback is not the only mechanism responsible for the formation of the pannonian basin an additional middle miocene rollback of a dinaridic slab is required to explain the observed structures furthermore the study provides constraints for the pre neogene orogenic evolution of this junction zone including the affinity of major crustal blocks obducted ophiolitic sequences and the sava suture zone

did the mediterranean marine reflooding precede the mio pliocene boundary paleontological and geochemical evidence from upper messinian sequences of tuscany italy abstract the events related to the messinian salinity crisis are among the most deeply investigated of earth s history according to the current hypothesis of neogene paleogeographic evolution approximately 5 5 ma ago after evaporitic sedimentation and before the mio pliocene boundary the mediterranean was characterized by the widespread development of non marine environments inhabited by molluscs and ostracods of brackish affinity the messinian post evaporitic deposits that testify such a dramatic environmental change are commonly referred to as lago mare and have been reported from several outcrops and boreholes throughout the entire mediterranean basin the origin of lago mare conditions is commonly interpreted as the result of the synergistic effect of both the humid climatic conditions and change of the drainage patterns at the mediterranean scale with the capture of paratethyan brackish waters a few recent studies however suggest that such a scenario probably represents an oversimplification of the original context from both a paleogeographical and paleoenvironmental point of view unfortunately the results of these studies have never been commonly accepted and the proposed evidences have been considered questionable in this paper we describe the fish assemblages from the lago mare deposits of two localities cava serredi and podere torricella located in the neogene hinterland basins of tuscany central italy these assemblages consists of a mixture of marine euryhaline and stenohaline taxa suggesting that the depositional environments were characterized by permanently open connections with a marine basin filled with normal marine waters in order to better define the paleontological significance of these upper messinian fish assemblages the oxygen carbon and strontium isotopic composition of fish otoliths and other fossils has been measured these isotopic compositions are strongly indicative of the presence of normal marine conditions close to the depositional environments testified by the sedimentary sequences thereby implying that the interpretation of the geochemical results are consistent with those derived from the paleoecological analyses of the fish assemblages based on the integrated paleoichthyological geochemical approach discussed in this paper it is possible to unambiguously demonstrate that normal marine rather than fresh or brackish waters were present in the mediterranean at least during the upper part of the lago mare event providing an unquestionable evidence that the marine refilling of the basin preceded the mio pliocene boundary

pre glacial topography of the european alps we present a topographic reconstruction of the european alps prior to quaternary glaciation based on the assumption that this topography was a steady state fluvial landscape eroding according to a stream power law but with spatially variable channel steepness we find high pre glacial channel steepness in the western alps and on the harder rocks of the basement and metamorphic nappes while lower values are often associated with weaker alpine flysch deposits the reconstructed pre glacial river network also provides an estimate of distribution and magnitude of glacial erosion and associated isostatic adjustment suggesting an increase of valley scale topographic relief and decrease of mean elevation throughout glaciation

magnetostratigraphy and radio isotope dating of upper miocene lower pliocene sedimentary successions of the black sea basin taman peninsula russia abstract we present a new chronology for the upper miocene to pliocene deposits of the black sea basin based on high resolution magnetostratigraphic data coupled with 40 ar 39 ar dating from the 475 m long zheleznyi rog section on the taman peninsula russia this section comprises the stratigraphic interval of the khersonian to kimmerian regional stages of the eastern paratethys our magnetostratigraphic record is based on biogenic and early diagenetic greigite components and yields a magnetostratigraphic sequence of 8 polarity zones a volcaniclastic ash layer at the upper part of the khersonian is radio isotopically dated at 8 69 0 18 ma the age of the khersonian meotian transition arrives at 8 6 or 8 2 ma which is significantly younger than earlier estimates the new age has important consequences for the hipparion datum in the eastern paratethys and implies that all vallesian fossil sites are younger than 11 2 ma the meotian stage has a total duration of 2 2 to maximum 2 6 myr and is marked by multiple erosional events the end of the paratethys sea is dated at 5 5 ma when the black sea becomes isolated from the caspian sea the dacian basin and the mediterranean

factors governing the pattern of glacier advances since the last glacial maxima in the transitional climate zone of the southern zanskar ranges nw himalaya abstract the present study investigates the relics of glacier advances and retreats in the transitional climatic zone of the southern zanskar range nw himalaya in response to the temporal changes in the indian summer monsoon ism and mid latitude westerlies the study identifies four glacier advances which are named from the oldest to youngest as the southern zanskar glacier stage 4 szs 4 to szs 1 the szs 4 remains undated however based on the existing chronology of the stratigraphically equivalent moraines trimlines in the region it is conjectured to the marine isotope stage 4 mis 4 the optical chronology obtained during the present study dates the szs 3 to 22 8 1 9 19 1 1 9 ka which corresponds to the last glacial maxima lgm the szs 2 is dated to 15 7 1 3 14 3 1 3 ka late glacial period whereas based on the chronology of the recessional moraines 4 9 0 4 4 5 0 3 ka the youngest szs 1 is assigned to 6 ka mid holocene the snout proximal moraines are attributed to the little ice age lia historical times the pulsating deglaciation associated with each advance since the lgm is represented by the recessional moraines and outwash gravel terraces the older gravel terrace is dated between 10 8 0 9 and 6 5 0 5 ka and is attributed to szs 2 deglaciation which is also manifested by the deposition of sandy facies in a relict lake sequence 6 7 0 6 ka and development of palaeosol 5 6 0 5 ka we propose that the glacial advances were triggered by the millennial scale cooling events during the periods of strengthened westerlies and thus suggest a synoptic scale coupling with the northern atlantic the deglaciation is suggested to occur during the warmer ism dominated phases the late holocene climatic instability that followed the recession of szs 1 is manifested by the development of rhythmites 3 8 0 5 ka loess 2 5 0 2 ka and palaeosol 2189 296 cal yr bp

oxygen isotopic and soluble ionic composition of a shallow firn core inilchek glacier central tien shan oxygen isotopic and soluble ionic measurements made on snow pit 2 m depth and firn core 12 4 m depth samples recovered from the accumulation zone 5100 m of inilchek glacier 43 n 79 e provide information on recent 1992 98 climatic and environmental conditions in the central tien shan region of central asia the combined 14 4 m snow pit firn core profile lies within the firn zone and contains only one observed melt feature 10 m temperature 12 c although some post depositional attenuation of the sub seasonal 18 o record is possible annual cycles are apparent throughout the isotope profile we therefore use the preserved 18 o record to establish a depth age scale for the core mean 18 o values for the entire core and for summer periods are consistent with 18 temperature observations and suggest the 18 o record provides a means to reconstruct past changes in summer surface temperature at the site major ion na k mg 2 ca 2 nh 4 cl no 3 so 4 2 data from the core demonstrate the dominant influence of dust deposition on the soluble chemistry at the site and indicate significant interannual variability in atmospheric dust loading during the 1990s anthropogenic impacts on nh 4 concentrations are observed at the site and suggest a summer increase in atmospheric nh 4 that may be related to regional agricultural nitrogen rich fertilizer use activities

paleogeography of the upper rhine graben urg and the swiss molasse basin smb from eocene to pliocene twenty paleogeographic maps are presented for middle eocene lutetian to late pliocene times according to the stratigraphical data given in the companion paper by berger et al this volume following a first lacustrine continental sedimentation during the middle eocene two and locally three rupelian transgressive events were identified with the first corresponding with the early rupelian middle pechelbronn beds and the second and third with the late rupelian serie grise fischschiefer and equivalents during the early rupelian middle pechelbronn beds a connection between north sea and urg is clearly demonstrated but a general connection between north sea urg and paratethys via the alpine sea is proposed but not proved during the late rupelian whereas in the southern urg a major hiatus spans early aquitanian to pliocene times early and middle miocene marine brackish and freshwater facies occur in the northern urg and in the molasse basin omm osm however no marine connections between these basins could be demonstrated during this time after the deposition of the molasse series a very complex drainage pattern developed during the late miocene and pliocene with a clear connection to the bresse graben during the piacenzian sundgau gravels during the late miocene pliocene and quaternary sedimentation persisted in the northern urg with hardly any interruptions the present drainage pattern of the rhine river from alpine area to the lower rhine embayment was not established before the early pleistocene

paleomagnetic and geochronologic constraints on the geodynamic evolution of the central dinarides the geodynamic evolution of the dinaride mountains of southeastern europe is relatively poorly understood especially in comparison with the neighboring alps and carpathians here we construct a new chronostratigraphy for the post orogenic intra montane basins of the central dinarides based on paleomagnetic and 40ar 39ar age data a first phase of basin formation occurred in the late oligocene a second phase of basin formation took place between 18 and 13 ma concurrent with profound extension in the neighboring pannonian basin our paleomagnetic results further indicate that the dinarides have not experienced any significant tectonic rotation since the late oligocene this implies that the dinarides were decoupled from the adjacent adria and the tisza dacia mega units that both underwent major rotation during the miocene the dinaride orogen must consequently have accommodated significant shortening this is corroborated by our ams data that indicate post middle miocene shortening in the frontal zone wrenching in the central part of the orogen and compression in the hinterland a review of paleomagnetic data from the adria plate which plays a major role in the evolution of the dinarides as well as the alps constrains rotation since the early cretaceous to 48 10 counterclockwise and indicates 20 of this rotation took place since the miocene it also shows that adria behaved as an independent plate from the late jurassic to the eocene from the eocene onwards coupling between adria and africa was stronger than between adria and europe adria continued to behave as an independent plate the amount of rotation within the adria dinarides collision zone increases with age and proximity of the sampled sediments to undeformed adria these results significantly improve our insight in the post orogenic evolution of the dinarides and resolve an apparent controversy between structural geological and paleomagnetic rotation estimates for the dinarides as well as adria