tectonics and sequence stratigraphy in messinian basins sicily constraints on the initiation and termination of the mediterranean salinity crisis deposits within the caltanissetta basin of central sicily have been important for developing the desiccating deep basin model for the messinian salinity crisis in the mediterranean linked structural and stratigraphic studies show that the sicilian depocenters are synclines related to underlying thrust structures of the frontal part of the maghrebian chain prior to the salinity crisis these basins were hydrodynamically linked through the foredeep to the mediterranean the precursor sediments terravecchia formation formed a delta sourced from the north early messinian regression acted on a range of paleobathymetries shallow in the north and progressively deeper in the south locally complicated by active thrust structures initial draw down of mediterranean base level is marked across the thrust belt by first cycle carbonates and evaporites on the structural highs and lows respectively vast accumulations of halite and potassium salts up to 1200 m are restricted to growing thrust synclines the different evaporite signatures may be related to different water conditions reflecting various meteoric and marine circulations across various subbasins with cyclicity reflecting high frequency variations in sea level a sequence stratigraphic model is developed to explain fractionation of evaporite facies between different paleobathymetric settings and to predict the temporal evolution of the successions in different subbasins thrusting provides accommodation space for evaporites and also controls the water pathways into the desiccating basins the intra messinian unconformity separating first and second cycle evaporites is a type 1 sequence boundary related to the forced regression associated with the acme of mediterranean desiccation an interpretation supported by local ravinement and incised valley fills the overlying second cycle evaporites are a combination of detrital reworked first cycle material and primary gypsum formed under brackish water regional onlap relationships and bed continuity suggest that this water body was of regional extent with a systematically rising base level these interpretations have several implications for messinian correlations in the mediterranean the deep basin evaporites correlate with an intra messinian unconformity that separates the two cycles on sicily and postdate the first cycle deposits regional base level was largely restored before the end of the salinity crisis

geochemistry of the peat bog at etang de la gruere jura mountains switzerland and its record of atmospheric pb and lithogenic trace metals sc ti y zr and ree since 12 370 14 c yr bp a 650 cm core from a swiss bog represents 12 370 14c years of peat accumulation and provides the first complete record of atmospheric pb deposition for the entire holocene excess non atmospheric sr in the peat was calculated by normalizing sr sc to crustal abundance this was used to differentiate between the ombrogenic section of the bog in which inorganic solids are supplied exclusively by atmospheric deposition and the minerogenic zone where mineral water interactions contribute metals to the peat while sediment dissolution contributes significantly to the sr inventory of the minerogenic section of the peat profile there is no measurable effect of this process on the pb burden isotopic analyses 204pb 206pb 207pb 208pb show that effectively all of the pb in the peat profile was supplied exclusively from the atmosphere to separate natural and anthropogenic pb sc was selected over ti y zr hf and ree as a conservative reference element which is supplied by soil dust aerosols derived from rock weathering enrichment factors ef were calculated using the pb sc ratio in the peat samples normalized to the natural background pb sc which is found in peats dating from 8030 to 5320 14c yr bp the results show that anthropogenic source have dominated the supply of atmospheric pb to the peat core continuously since 3000 14c yr bp the aerosols supplied to the bog can be divided into 3 classes a pre anthropogenic older than 3000 14c yr bp with pb ef 1 194 b pre industrial dating from 3000 240 14c yr bp with pb ef 2 but 20 and 206pb 207pb 1 179 elevated soil dust fluxes are observed at 5320 8230 and 10 590 14c yr bp the latter corresponds to the younger dryas aluminum zr hf and ree sc ratios also are elevated at the same depths suggesting differences in particle size wind strength or source regions pre anthropogenic aerosols deposited since 8230 14c yr bp reveal pb sc which is significantly higher and 206pb 207pb which is less radiogenic than during the early holocene while the trend toward increasing pb sc could be due to chemical weathering and soil development this could not explain the shift in pb isotopic composition the changes which took place at 8230 14c bp therefore may be related to a large scale climatic reorganization which at present is poorly understood

onshore to offshore reconstruction of the messinian erosion surface in western sardinia italy implications for the messinian salinity crisis new outcrops in the sinis peninsula sardinia italy allow a detailed description of the messinian erosion surface the correlation between outcrops industrial seismic data and data collected offshore oristano from a recent cruise permits reconstruction of the geometry of this surface from presently emerged interfluves to the deep canyons offshore with onshore an eroded karstic plateau presently cropping out over a 20 km 5 km area well preserved karst structures occur locally and can form several metres high reliefs the southernmost edge of the plateau is limited by a cliff the karstic plateau and the cliff are sealed by transgressive deposits of pliocene age offshore an interfluve zone with a mostly flat and low angle dipping plateau westward dissected by paleovalleys which were identified down to a depth of 2000 m in the oristano gulf messinian paleovalleys were also identified the capo san marco paleocliff was probably located on the edge of a canyon onshore only one major erosion surface was identified located at the top the messinian sequence offshore this surface extends down to the abyssal plain the surface was emplaced above deposits related to the terminal carbonate complex this indicates that the marginal evaporites are older than the major drawdown of the mediterranean sea level the major drawdown is related to the deposition of the deep evaporites

extending the astronomical polarity time scale into the miocene an astronomical time scale is presented for the late miocene based on the correlation of characteristic sedimentary cycle patterns in marine sections in the mediterranean to the 65 n summer insolation curve of la90 1 2 with present day values for the dynamical ellipticity of the earth and tidd dissipation by the moon this correlation yields ages for all sedimentary cycles and hence also for the recorded polarity reversals and planktonic foraminiferal and dinoflagellate events the tortonian messinian t m boundary placed at the first regular occurrence of the globorofuliu conomiozea group in the mediterranean is dated at 7 24 ma the duration of the messinian is estimated at 1 91 myr because the miocene pliocene boundary has been dated previously at 5 33 ma 3 the new time scale is confirmed by oar 3gar ages of volcanic beds and by the number of sedimentary cycles in the younger part of the mediterranean messinian

lead atmospheric deposition rates and isotopic trends in asian dust during the last 9 5 kyr recorded in an ombrotrophic peat bog on the eastern qinghai tibetan plateau a full understanding of the atmospheric pb cycle in asia during the holocene is key to palaeoclimate studies of past atmospheric circulation patterns as well as to assess the impact of increasing industrial activities in this region however long term records of atmospheric pb isotopic trends in asia are still sparse consequently we study changes in the concentrations fluxes and isotopic signature of deposited pb contained in a 14c dated peat core from the eastern qinghai tibetan plateau dating back to 9 5 kyr bp and present the first peat record of the changing isotopic composition of atmospheric pb in dust in asia during this time lead concentrations and fluxes vary between 2 96 21 58 lg g 1 and 0 06 3 52 mg m 2 y 1 respectively with an average pb baseline of 6 80 4 18 lg g 1 these values agree with other pb studies of lake and peat archives in china but are one order of magnitude larger than early and mid holocene values measured in europe lead isotopic variability throughout the core is small varying between 206pb 207pb 1 190 1 197 206pb 204pb 18 648 18 786 207pb 204pb 15 666 15 694 and 208pb 204pb 38 890 39 090 the application of bayesian trans dimensional changepoint modelling to the pb dataset enabled the identification of eight significant changes in the isotopic composition of the deposited pb such changes mark different phases of atmospheric pb deposition and hence variations in atmospheric circulation patterns and environmental conditions temporal variations in the potential natural and or anthropogenic pb sources are assessed based on the 206pb 207pb 208pb and 204pb isotopic composition and the 1 pb ratio of the peat samples our results suggest that pb deposition throughout the holocene was governed by local deposition and long range input from natural dust sources in northwestern taklamakan desert and qaidam basin and northern china badain jaran and tengger deserts input from the northern sources seems to have been particularly important between 3 1 2 7 kyr bp and 1 7 0 9 kyr bp suggesting a possible strengthening of the east asian winter monsoon in agreement with previous reconstructions in asia based on the pb sc and isotopic composition profiles we do not note any evidence for anthropogenic pb derived from the thriving mining or smelting activities in northern and eastern china in the last few millennia suggesting that atmospheric deposition to this region of the eastern tibetan plateau was dominated by natural pb fluxes these can serve as a true asian background value against which anthropogenic impacts can be quantified our results confirm that the combination of radiogenic isotopes pb and trace elements in peat bogs enables observational reconstructions of changes in past regional atmospheric circulation such records will enable more refined interpretations of marine and terrestrial palaeorecords in asia and the pacific and consequently provide further constraints for changes in ocean and atmospheric circulation and for the testing of palaeoclimate models of circulation patterns

lithofacies and faunal succession faunal phase analysis as a tool in unravelling climatic and tectonic signals in marginal basins messinian miocene sicily many basins are filled under the influence of tectonics and variable climatically driven processes unravelling the relative contributions of these is generally easier in fossiliferous sequences if faunal diversity patterns are considered in conjunction with lithofacies analysis this approach has been successfully applied to late miocene strata of sicily where progressive restriction and desiccation within the sicilian caltanissetta region occurred under a semi arid climate during the messinian stage this restriction was partly due to antarctic cooling which produced palaeo mediterranean sea level oscillations during the early messinian as a prelude to closure of the atlantic connections in addition regions within this afro european plate collision zone were also subjected to syndepositional tectonic deformation associated with progressive perched basin development above foreland south verging thrust sheets the relative impacts of climatic eustatic versus tectonic control on sedimentation patterns within these perched basins has been debated at length however progress towards resolving this problem by a combined approach involving lithofacies analysis and faunal phase analysis provides clues for separating the effects of the controlling factors faunal phase analysis identifies general faunal associations with minimal emphasis on species diversity the resulting phase plots for early messinian strata appear to be transgression skewed when controlled by eustatic cyclicity and regression skewed when driven by regional tectonics associated with perched basin tectonics

using high resolution stratigraphy to date fold and thrust activity examples from the neogene of south central sicily the integration of structural and stratigraphic data is fundamental for determining rates of deformation in the uppermost continental crust the high temporal resolution provided by neogene marine sediments is used here to examine deformation rates in part of a thrust belt chosen from the maghrebian orogen of sicily conventional biozonal stratigraphy calibrated against the geomagnetic polarity time scale shows that individual thrust fold structures grew steadily over many millions of years structures across the thrust belt were active at the same time and accommodated bulk shortening rates of c 0 5 mm a 1 in contrast the basal detachment operated about ten times faster these results are in broad agreement with some theoretical models for orogenic wedge kinematics shore line carbonate successions calibrated with precession cycles of sea level change provide a very high resolution temporal scale with which to chart tilt rates on fold limbs 1 27 6 ka 0 036 ka 1 these show that fold amplification was continuous although the rates may have varied with time incremental tilting of limbs during fold amplification is not predicted by popular models of fault bend and 9fault propagation9 folding geometric modelling suggests that folding occurred by limb rotation with minor hinge migration during buckling above buried thrusts thus stratigraphic data may be used to examine the kinematic evolution of thrust fold systems along regional cross sections and of local structures however the types of structural models that can be tested using estimates of deformation rates depend upon the chrono stratigraphic resolution available for the syn tectonic sediments

changes in natural lead copper zinc and cadmium concentrations in central greenland ice from 8250 to 149 100 years ago their association with climatic changes and resultant variations of dominant source contributions abstract we present here the first reliable time series of pb cu zn and cd in greenland ice for the last climatic cycle they were obtained by analysing various sections of the 3028 8 m grip deep ice core drilled at summit central greenland our results show that climatic changes have led to large variations in the concentrations of natural pb cu zn and cd in the high latitude troposphere of the northern hemisphere between the interglacial and glacial periods concentrations have varied by factors of 320 for pb 100 for cu 36 for zn and 13 for cd based on a good correlation between each heavy metal and al pb and cu are found to have mainly originated from soil and rock dust for both glacial and interglacial periods on the other hand continental biogenic emissions were the main source of cd and to a lesser extent zn in the arctic troposphere during the warm eemian and the pre boreal to holocene transition whereas wind blown dust was the predominant source for these two metals during the cold glacial climatic stages this characteristic change of relative cd and zn contributions from different sources in contrast to that for pb and cu is well documented in the ice from the last deglaciation period 15 000 to 8250 yrs ago after the younger dryas event ended a remarkable increase of cd al and zn al ratios occurred from 13 000 to 9300 yrs ago which is consistent with the progressive expansion of vegetation following the retreat of the north american and north eurasian ice sheets the subsequent decrease of these ratios to holocene values can be explained by the stabilization of atmospheric circulation in the northern high latitude regions which became similar to that for the holocene due to further reduction of the laurentide ice sheet finally the observed variations of the metal al ratios suggest changes in the soil and rock dust source regions in parallel with climatic changes which have altered the mean composition of the crustal particles transported to the arctic

origin and age of the mediterranean messinian evaporites implications from sr isotopes strontium isotope ratios from the messinian late miocene 6 4 to 4 85 ma evaporites of the mediterranean basin 1 2 support a subdivision into stratigraphically lower predominantly marine deposits lower evaporites lev lower gypsum and main salt characterized by sr isotopic ratios generally equivalent to those of messinian seawater and stratigraphically higher deposits upper evaporites uev with 87sr 86sr ratios lower than messinian seawater the range of 87sr 86sr ratios of the lev unit from the eastern mediterranean overlap with values obtained from essentially coeval red sea evaporites 3 strontium isotopic ratios measured from the upper evaporites however are lower and a high proportion of this sr was probably derived from low 87sr 86sr continental runoff that characterizes much of this basin 4 these results therefore strongly support depositional models utilizing a deep desiccated basin 1 with a constant marine inflow during the early stages including salt formation followed by a series of long lasting and sometimes isolated desiccation events that produced a strong but variable continental influence on the sr isotopic compositions of the uev strontium isotopic measurements can also be used to asses the actual timing of the deposition of the lev ratios obtained from oyster fragments and foraminifers from pre evaporitic units at odp site 654 tyrrhenian sea suggest that the major rifting phase in this region occurred between 8 and 6 5 ma ratios obtained from the early lev from the mediterranean sea suggest that initiation of evaporite deposition began about 5 65 ma ago results from units immediately overlying the uev in sicily suggest termination of evaporite deposition about 4 9 ma ago errors associated with these age estimates are about 0 5 ma 2

refining the pre industrial atmospheric pb isotope evolution curve in europe using an 8000 year old peat core from nw spain abstract pb pollution has existed for several millennia and remains relevant today by using peat cores as environmental archives it is possible to reconstruct this long history on a regional scale this is a significant contribution to the findings from ice core records the only other archive recording purely atmospheric additions without information that allows linking and comparison between sites regionally within europe and elsewhere our ability to make coherent global models of the natural pb cycle and anthropogenic forcing of this cycle is limited in this respect the characteristics of the pb pre pollution aerosol ppa are important to define globally we characterize for the first time a ppa in southern europe with pb 0 78 0 86 g g 1 net pb accumulation rates of 0 032 0 030 mg m 2 y 1 and a 206 pb 207 pb signature of 1 25470 0 02575 this ppa pb isotope signature is more radiogenic than that found thus far in western and northern europe spain is a historically important mining site using three isotope plots and a pool of potential pb isotope signatures a detailed source appointment of both natural and anthropogenic pb sources was made we found evidence of saharan aridification and its termination 4400 bp and or agricultural signals and strong local control from rock and soil of the pb ppa human impact is first recorded at 3210 bp but does not exceed 50 of deposited pb until 3005 bp mines in se spain dominate early pb pollution history at this site during the rise of roman rule contributions come from mines in n nw and sw spain with no strong indication of other european mining activities in medieval and industrial times local contributions to the peat bog are reduced

extending the climatic precession curve back into the late miocene by signature template comparison the rhythm of sedimentary cycles reflecting the climatic precession signal 19 and 23 kyr components from the upper miocene of the bou regreg section at ain el beida near rabat morocco had been analyzed to determine the age of the geomagnetic polarity reversals of subchron 5n1 c3an 1n a new method of analysis of cycle signatures uses adjusted data series as represented by a signal obtained from grey level traces through image enhanced photographs of the sediment cycles the measured timeless signal is reduced and geometrically transformed to a signature template in order to compare its pattern with similar time constrained segments of the target precession signal retrodicted for 35 n conventional statistical and spectral analysis tests are used to regress to the best possible fit a date estimate of 5 94 ma for the chron 5 gilbert boundary c3an 1n c3r which occurs near the times of the closure of the rifian corridor and the beginning of the drawdown phase of the messinian salinity crisis is found to be in close agreement with independent approximations derived from extrapolation of sea floor spreading radiometric dating and younger earth orbital tuning ages

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

historical records of atmospheric pb deposition in four scottish ombrotrophic peat bogs an isotopic comparison with other records from western europe and greenland 1 cores collected from ombrotrophic peat bogs in west central east central northeast and southwest scotland were dated 14c 210pb and analyzed icp oes icp ms to derive and compare their historical records of atmospheric anthropogenic pb deposition over the past 2500 years on the basis of pb isotopic composition e g 206pb 207pb clear indications of pb contamination during the pre roman roman post roman and medieval periods were attributed to the mining and smelting of pb ores from britain and elsewhere in europe between the 17th and early 20th centuries during the industrial period the mining and smelting of indigenous scottish pb ores were the most important sources of anthropogenic pb deposition at three of the sites in contrast at the most southerly site influences from the use of both british pb ores and imported australian pb ores in more southern parts of britain since the late 19th century were evident at each of the sites australian pb influenced car exhaust emissions from the 1930s to late 1990s along with significant contributions from coal combustion until the late 1960s and onset of the postindustrial period were evident atmospheric anthropogenic pb deposition across scotland was greatest 10 to 40 mg m 2 a 1 between the late 1880s and late 1960s increasing southward declining to 0 44 to 5 7 mg m 2 a 1 by the early 2000s the records from four peat bogs extend knowledge of the chronology of atmospheric pb deposition trends across the northern hemisphere there being general agreement with other environmental archive records from not only scotland but also other countries in western europe and greenland nevertheless during all periods investigated here the isotopic composition of atmospheric pb deposition across western europe and greenland exhibited variations in the relative importance of different sources of anthropogenic pb as well as some differences in timings and magnitudes of anthropogenic pb contamination arising from variations in local and regional sources of pb deposition and possibly climatic regimes

stratigraphic variations control deformation patterns in evaporite basins messinian examples onshore and offshore sicily italy three dimensional seismic data are increasingly resolving original compositional heterogeneity and structural complexity in evaporitic successions within sedimentary basins the relationship between basin structure evaporite composition and its influence on subsequent deformation are investigated here using messinian examples from the maghrebian thrust system of sicily and applied to the adjacent ionian sea bed by integrating outcrop and onshore subsurface data we demonstrate variations in evaporite stratigraphies deposited across thrust top basins and how these variations have controlled subsequent deformation of these basins gypsum and carbonate units develop broad single layer buckle fold trains with wavelengths reflecting layer thickness the development of deformation appears limited by bending resistance at fold hinges which can be overcome by syntectonic erosion in contrast the thick halite and k salt accumulations in growth synclines have deformed with short wavelength folds and distributed strain these structures can display rapid lateral variations on a scale of hundreds of metres similar structural styles with buckle fold trains passing laterally into more homogeneously shortened short wavelength folding are evident on seismic data from the buried messinian interval beneath the ionian sea using the sicilian outcrop as analogues the structural styles for the ionian may be used to infer evaporite type in these subsurface examples

metal emissions from kilauea and a suggested revision of the estimated worldwide metal output by quiescent degassing of volcanoes abstract measurements of a large suite of metals pb cd cu zn and several others and sulfur at kilauea volcano over an extended period of time has yielded a detailed record of the atmospheric injection of ordinarily rare metals from this quiescently degassing volcano representative of an important type we have combined the kilauea data with data of recent studies by others emissions from volcanoes in the indonesian arc the large laki eruption of two centuries ago etna estimates of total volcanic emissions of sulfur to form the basis for a new working estimate of the rate of worldwide injection of metals to the atmosphere by volcanoes the new estimate is that volcanoes inject a substantially smaller mass of ordinarily rare metals into the atmosphere than was stated in a widely cited previous estimate j o nriagu a global assessment of natural sources of atmospheric trace metals nature 338 1989 47 49 our estimate which is an upper limit is an annual injection mass of about 10 000 tons of the metals considered versus the earlier estimate of about 23 000 tons also the proportions of the metals are substantially different in our new estimate

general circulation and transport in saturn s upper troposphere and stratosphere abstract we present a model for the general circulation and dynamical transport in saturn s upper troposphere and stratosphere and derive the effective advective circulation and eddy transport coefficients required for use in two dimensional latitude altitude photochemistry transport models a three dimensional outer planet general circulation model opgcm is used to generate the transport data we find that the opgcm adequately captures the global scale pole to pole temperature contrast but overestimates mid and high latitude temperatures in the summer hemisphere by 5 k in addition the model reproduces the local temperature minimum seen at the equator in cassini composite infrared spectrometer cirs 0 1 mbar data but not the local maximum in 1 mbar temperatures suggesting that it is capturing the phase of saturn s semiannual oscillation associated with a temperature minimum at the equator but not the opposite phase the meridional circulation at low latitudes is found to be dominated by a seasonally reversing hadley circulation characterized by upwelling near the equator cross equatorial flow from summer to winter hemisphere and strong subsidence centered near 25 latitude in the winter hemisphere the cross equatorial flow induces an asymmetry in which the equatorial jet is found to be stronger in the winter than in the summer stratosphere the location of the subsidence near 25 n for l s 310 coincides with local maxima in acetylene diacetylene and methylacetylene mixing ratios measured by cassini cirs guerlet s fouchet t bezard b moses j i fletcher l n simon miller a a flasar f m 2010 icarus 209 682 695 this result supports the suggestion by guerlet et al 2010 that the hydrocarbon abundances are enhanced at this latitude by pronounced downward transport of hydrocarbon rich air from above the lateral eddy diffusion coefficient is found to typically be 10 5 10 6 m 2 s 1 at mid latitudes implying meridional eddy transport time scales of order 100 1000 years

an 8000 year history of landscape climate and copper exploitation in the middle east the wadi faynan and the wadi dana national reserve in southern jordan abstract investigations of geomorphology geoarchaeology pollen palynofacies and charcoal indicate the comparative scales and significance of palaeoenvironmental changes throughout the holocene at the junction between the hyper arid hot wadi arabah desert and the front of the mediterranean belt mountains of edom in southern jordan through a series of climatic changes and episodes of intense mining and smelting of copper ores early holocene alluviation followed the impact of neolithic grazers but climate drove fluvial geomorphic change in the late holocene with a major arid episode corresponding chronologically with the little ice age causing widespread alluviation the harvesting of wood for charcoal may have been sufficiently intense and widespread to affect the capacity of intensively harvested tree species to respond to a period of greater precipitation deduced for the roman byzantine period a property that affects both taphonomic and biogeographical bases for the interpretation of palynological evidence from arid lands with substantial industrial histories studies of palynofacies have provided a record of human and climatic causes of soil erosion and the changing intensity of the use of fire over time the patterns of vegetational climatic change and geomorphic changes are set out for this area for the last 8000 years

the petrology and palaeoenvironment of the sortino group miocene of se sicily evidence for periodic emergence the sortino group of carbonates consists of three formations which developed on a shallow marine shelf during tortonian and lower messinian times the two lower formations contain three bioherms and are intercalated with thick volcaniclastic sequences the youngest formation is dominated by shoal water lagoonal and peri tidal carbonates early submarine lithification is well developed within the bioherms and consists of construction by both algae and invertebrates the development of peloidal micrites and isopachous fringe growth superimposed upon these are a series of both meteoric phreatic and vadose textures related to episodic emergence of the bioherms these features include bladed cements showing cathodoluminescence pendent cements brecciation alveolar texture and palaeosols the sicilian strata may be directly correlated with the maltese islands sequence and collectively exhibit the effects of fluctuating mediterranean sea levels at an early stage in the late miocene salinity crisis

an important current reversal influx in the rifian corridor morocco at the tortonian messinian boundary the end of tethys ocean atlantic psychrospheric and temperate mesopelagic faunas found in the lower messinian marls in morocco indicate that a strong eastward flowing bottom current was present in the rifian corridor before the salinity crisis this influx began just before diatomite deposition in the paleo mediterranean continued during a decrease in species diversity in coral reef formation and diminished with the initial stages of brine concentration in the deep water phase of the crisis the influx is most readily studied in a condensed section of marl in the bou regreg valley near rabat the beginning of this siphon event coincides with the tortonian messinian boundary 6 4 ma subchron 6n1 it is identified by 1 a change in the planktonic foraminifera from dominance of warm tropical epipelagic globorotalia menardii with globigerinoides to the temperate mesopelagic gl miotumida plexus with conomiozea 2 the sudden appearance of an upper psychrospheric ostracode fauna with agrenocythere pliocenica and oblitacythereis ruggierii 3 a change in nannoflora and 4 beginning of the 6 3 ma global carbon shift the initial strong influx stage of the siphon lasted at least 0 7 m y decreasing after the middle of chron 5 ca 5 7 to be lost ca 5 3 ma conditions for the siphon formed when the continental climate created a deficit in the water budget of the paleo mediterranean sea the reversal took place when tectonic movement in the foredeeps of the betic rif orogene changed the thresholds of the twin straits the rifian corridor and the iberian portal inflow increased rapidly in the southern corridor to draw in waters from beneath the rising atlantic pycnocline while paleo mediterranean overflow water pmow continued out of the northern iberian portal the invasion of nappes or olistoliths first into the portal and then into the corridor led to the end of the outflow of the pmow terminating the need for the siphon and then to the isolation of the paleo mediterranean

climate change records between the mid and late holocene in a peat bog from serra do xistral sw europe using plant macrofossils and peat humification analyses abstract to implement models of global change information from peripheral regions and concerning the distinction between global and local events is needed in this context we studied the occurrence of hydrological changes over the last 5300 years in the southern most european area of active blanket bogs the reconstruction of the bog surface wetness was performed on the basis of the analysis of plant macrofossils and peat humification to interpret these proxies the current botanical composition of the bog and the ecological behavior of the different plant species were used from its present ecological behavior we have established the main indicator species for different bog surface wetness the seeds of juncus bulbosus and drosera rotundifolia which were significantly correlated with the humification index as well as the seeds and rhizomes of eriophorum angustifolium were the primary indicators for wetness the sphagnum species are not abundant and most are restricted to wet and damp periods the concordance between both proxies in spite of certain discrepancies allowed us to estimate the chronological sequence of hydrological changes along the bog profile we have differentiated 10 wet periods during which the bog surface could be flooded or wet 5300 4850 4350 3900 3550 3350 3150 3050 2700 2450 2250 2150 1950 1300 1150 1050 900 800 and 700 20 cal yr bp these identified wet periods are in agreement with previous paleoclimate studies with different spatial scales and proxies

a spatially resolved high spectral resolution study of neptune s stratosphere abstract using texes the texas echelon cross echelle spectrograph mounted on the gemini north 8 m telescope we have mapped the spatial variation of h2 ch4 c2h2 and c2h6 thermal infrared emission of neptune these high spectral resolution spatially resolved thermal infrared observations of neptune offer a unique glimpse into the state of neptune s stratosphere in october 2007 ls 275 4 just past neptune s southern summer solstice ls 270 we use observations of the s 1 pure rotational line of molecular hydrogen and a portion of the 4 band of methane to retrieve detailed information on neptune s stratospheric vertical and meridional thermal structure we find global average temperatures of 163 8 0 8 155 0 0 9 and 123 8 0 8 k at the 7 0 10 3 0 12 and 2 1 mbar levels with no meridional variations within the errors we then use the inferred temperatures to model the emission of c2h2 and c2h6 in order to derive stratospheric volume mixing ratios hence forth vmr as a function of pressure and latitude there is a subtle meridional variation of the c2h2 vmr at the 0 5 mbar level with the peak abundance found at 28 latitude falling off to the north and south however the observations are consistent within error to a meridionally constant c2h2 vmr of 3 3 0 9 1 2 10 8 at 0 5 mbar we find that the vmr of c2h6 at 1 mbar peaks at the equator and falls by a factor of 1 6 at 70 latitude however a meridionally constant vmr of 9 3 2 6 3 5 10 7 at the 1 mbar level for c2h6 is also statistically consistent with the retrievals temperature predictions from a radiative seasonal climate model of neptune that assumes the hydrocarbon abundances inferred in this paper are lower than the measured temperatures by 40 k at 7 10 3 mbar 30 k at 0 12 mbar and 25 k at 2 1 mbar the radiative seasonal model also predicts meridional temperature variations on the order of 10 k from equator to pole which are not observed assuming higher stratospheric ch4 abundance at the equator relative to the south pole would bring the meridional trends of the inferred temperatures and radiative seasonal model into closer agreement we have also retrieved observations of c2h4 emission from neptune s stratosphere using texes on the nasa infrared telescope facility irtf in june 2003 ls 266 using the observations from the middle of the planet and an average of the middle three latitude temperature profiles from the 2007 observations 9 5 of ls later the seasonal equivalent of 9 5 earth days within earth s seasonal cycle we infer a c2h4 vmr of 5 9 0 8 1 0 10 7 at 1 5 10 3 mbar a value that is 3 25 times that predicted by global average photochemical models

the calabrian stage pleistocene highstand in malta a new marker for unravelling the late neogene and quaternary history of the islands abstract the late neogene and quaternary sedimentary record within the maltese islands is very fragmentary and has generally been ignored by sedimentologists local stratigraphies for parts of the quaternary have been erected from vertebrate remains contained in quaternary cave and fissure deposits of the islands however no coherent correlation scheme has been proposed in which to encompass them the situation is exacerbated by the absence of datable fossils within the majority of quaternary deposits considerable progress in resolving these problems is however possible if recourse is made to the post messinian late miocene erosion features evidenced in the topography of the islands in particular a hitherto unrecognized marine erosion surface the san leonardo marine abrasion surface is described and dated by reference to the marine deposits san leonardo beds lying directly above it and similarities to contemporaneous se sicily marine deposits this provides an end calabrian stage emilian sub stage base line upon which to hang fragmentary information on later events that have shaped the topography of the maltese islands from this it can be confirmed that a tectonic deformation event spanning latest messinian to mid pliocene times uplifted the islands and reactivated previously incipient graben systems this deformation episode is shown to have ceased within the islands well before the early calabrian before c 1 6 ma subsequent minor regional uplift and eustacy together with subaerial weathering processes have been the principal agents in shaping the islands collectively these processes have prevented terrestrial animal migrations into the maltese islands from north africa since messinian times however the infrequent re establishment of a marine lowstand isthmus virtually linking malta with se sicily has permitted opportunistic animal migrations into the islands and the presence of these greatly aids in dating the sedimentological events

magnetostratigraphic biostratigraphic and stable isotope stratigraphy of an upper miocene drill core from the sale briqueterie northwestern morocco a high resolution chronology for the messinian stage we report a high resolution stable isotope carbonate magnetostratigraphic and biostratigraphic record from a 175 m drill core from the sale briqueterie which is part of the bou regreg section in northwestern morocco the sale drill core spans the interval from paleomagnetic chron c4n partim to c3r earliest gilbert which represents the time leading up to and including the isolation and desiccation of the mediterranean i e the messinian salinity crisis during chrons c3an and c3ar 6 935 to 5 894 ma the isotope and carbonate signals display quasi periodic variations with estimated periods of 40 and 100 kyr respectively we interpret the 40 kyr 18o variations as reflecting changes in global ice volume caused by obliquity induced changes 41 kyr in solar insolation in polar regions the 100 kyr carbonate variations probably represent long term modulation of the amplitude of the precessional cycle 21 kyr which is not resolved by our sampling frequency the cyclic nature of the oxygen isotope signal permits us to extend the isotope nomenclature of shackleton et al 1994a from stage tg24 in chron c3r earliest gilbert to stage c3ar 18o 18 at the base of chron c3ar 6 935 ma a major change in paleoceanographic conditions is recorded across the tortonian messinian boundary which we correlate to chron c3bn at 7 04 ma benthic foraminiferal 18o values increased by an average of 0 4 in two steps at 7 17 ma and 6 8 ma and 13c values decreased by 0 7 0 8 between 7 1 and 6 8 ma representing the late miocene carbon shift the first step in 18o values coincides with an inferred reversal in deep water circulation through the rifian corridor and the second correlates with the base of the tripoli formation and onset of crisis conditions in the mediterranean we suggest that the increase in 18o values represents at least in part an increase in global ice volume that lowered sea level and contributed to the establishment of a negative water budget in the mediterranean average 18o values remained high throughout most of chrons c3ar and c3an reaching maximum 18o values during isotope stages tg20 and 22 in chron c3r earliest gilbert the glacio eustatic falls associated with these events may have resulted in the complete isolation of the mediterranean from the world ocean shackleton et al 1994a following stage tg12 in the sale record there exists a trend toward progressively lower 18o values that may represent a series of marine transgressions that eventually reflooded the mediterranean and ended the salinity crisis

climate changes lead pollution and soil erosion in south greenland over the past 700 years date of acceptance 05 06 2015 this research was made possible through funding provided by the leverhulme trust the spanish ministry of science and innovation project cgl2010 20672 and xunta de galicia grants r2014 001 and gpc2014 009 n silva sanchez is currently supported by a fpu pre doctoral grant ap2010 3264 funded by the spanish government kirsty golding andy mcmullen and ian simpson are thanked for their assistance with fieldwork alison sandison produced the maps pete langdon and two anonymous referees are thanked for comments that helped to improve the paper

controls on faunal and sediment cyclicity within the tripoli and calcare di base basins late miocene of central sicily abstract cyclicity within the late miocene tripoli and calcare di base formations of sicily was controlled by two processes a partial evaporation of palaeomediterranean waters but with periodic replenishment by atlantic derived inflow on several occasions during the late tortonian and messinian stages b deformation of a regional foreland basin and associated satellite basins perched above south verging sedimentary thrust sheets these were intermittently set in motion by active plate collision onto the passive african plate margin although it is not possible to discriminate fully the world eustatic signal under such a scenario nevertheless sufficient recolonization by marine faunas in these sicilian basins occurred to permit modelling of onlap offlap events for the late miocene intervals basin wide correlation of these variably fossiliferous formations hangs on the recognition of a late tortonian early messinian onlap event marked by coral reef development at the top of the terravecchia formation around the northern margins of the region a further carbonate episode calcare di base formation lies above a transgressive surface and directly overlies fluvial conglomerates at the top of the terravecchia formation around the northern margins of the basin the calcare di base is partly diachronous with the top of the tripoli formation in the foreland basin but further north it oversteps the coral reefs on the southern margins of the madonie mountains a variable number of internal tripoli formation cycles confirmed on both faunal and sedimentological grounds and calcare di base cycles demonstrated only by sedimentation patterns have been recognized this minor cyclicity is considered to have resulted from periodic tectonic uplift and isolation of foreland basin and associated perched basins this isolation controlled both influx of siliciclastic sediment and access by marine biota prolonged basin isolation during the deposition of the tripoli formation lead to rapidly declining diversity patterns in both benthonic and planktonic communities benthonic foraminifera disappeared early in many cycles with oligotypic planktonic foraminifera and radiolaria remaining longest under increasingly hostile conditions only diatoms remained each new cycle is marked at its base by a return to near normal conditions and a relatively diverse biota although faunas were stressed during the isolation events no clear evidence of salinity increase is seen rather we consider that a combination of oxygen depletion especially on basin floors receiving prolific algal bioproduction and toxin build up generally as the by product of algal metabolic processes was the cause the calcare di base cycles are more difficult to interpret on account of the virtual absence of biota here the cycles are clearly related to desiccation and salinity increase during times of restriction the base of each cycle is marked by brine dilution and basin flooding with some evidence of low diversity microfauna input in the early cycles we envisage a late miocene palaeogeography with thrust fold belts well established to the north of sicily and a ne sw oriented seaway developed ahead of them to the south of this seaway lay an en echelon belt of ne sw oriented submarine ridges and localised basins which effected a sill or at times a barrier between the seaway and the tripoli basins a broad diatom dominated perched basin complex extended along the southern margin of the thrust related ridges and was intimately linked to a broad foreland basin also diatomitic lying immediately to the south the foreland basin was separated from a further open sea area in southern sicily by a second ne sw oriented sill now hidden by later overthrusting it is suggested that similar tectonic scenarios were responsible for isolating diatomaceous basin elsewhere in the mediterranean during late miocene times

latest miocene benthic δ 18 o changes global ice volume sea level and the messinian salinity crisis oxygen isotope evidence indicates high but variable 18o values in benthic foraminiferal calcite during the latest miocene and earliest pliocene these high values may represent increases in global ice volume and associated sea level fall the 18o record resembles glacial interglacial cycles but with only one third the amplitude of the late pleistocene signal this variability may reflect instability in the antarctic ice sheet and palaeomagnetic correlation points to an isotopic event coinciding with the isolation and desiccation of the mediterranean basin during the latest messinian

the western edge of the mediterranean pelagian platform a messinian mixed siliciclastic carbonate ramp in northern tunisia the marine messinian deposits of tunisia cover a narrow littoral strip some 300 km long between the northern bizerte and cap bon areas and the central eastern sahel region litho and biofacies analysis of six stratigraphic sections reveals the distinctive features of these deposits the lower messinian deposits are characterized by ubiquitous siliciclastics and abundant oolitic bioclastic limestones organized in an eastward facing ramp westward landward this ramp changes into coastal lagoons sometimes containing evaporites eastward the ramp passes to the reefal pelagian platform extending as far as lampedusa two main sedimentary cycles are distinguished 1 an early messinian siliciclastic retrogradational then oolitic bioclastic progradational cycle beni khiar formation and lower oued bel khedim formation 2 a late messinian brackish to continental cycle that probably accumulated in rapidly subsiding lagoons cued el bir formation and upper oued bel khedim formation the tunisian early messinian cycle is partly eustatically controlled but the late messinian cycle cannot be confidently correlated to other well known messinian series because of tectonic movements the lower messinian deposits of tunisia are also characterized by abundant suspension feeding organisms molluscs and bryozoans and rare corals calcareous algae echinoids and larger benthic foraminifers the proposed palaeoenvironmental model shows that the lower messinian ramp of tunisia was located on a current protected margin and subjected to continent derived sediment and nutrient supply eastward nutrient influx diminished and a shallow water isolated carbonate platform with coralgal facies developed between the western and the eastern mediterranean basins the main hydrological connection between these two basins occurred through a narrow seaway situated to the northeast of the pelagian platform south of sicily and malta

a peat bog record of natural pre anthropogenic enrichments of trace elements in atmospheric aerosols since 12 370 14 c yr bp and their variation with holocene climate change abstract a peat bog in the jura mountains switzerland provides a continuous record of peat accumulation since 12 370 14 c yr bp periods of enhanced soil dust deposition 10 590 14 c yr bp 8230 14 c yr bp and after 5320 14 c yr bp are characterized by strongly elevated ti sc and zr sc ratios which imply an increase in the abundance both relative and absolute of heavy minerals such as ilmenite and zircon with respect to trace elements such as cu zn as cd sb and au the m sc ratios are at their lowest and often approach crustal values during periods of enhanced soil dust deposition the lowest rates of atmospheric deposition of soil dust date from 8030 to 5320 14 c yr bp corresponding to the holocene climate optimum but here many trace elements exhibit their greatest natural enrichments the average enrichment factor calculated using sc as the reference element and normalizing to crustal abundance was zn 4 1 1 4 sb 4 8 1 4 cu 8 8 3 3 as 14 9 3 2 au 53 9 25 1 and cd 357 4 53 8 these enrichments cannot be explained by chemical diagenesis within the deeper sections of the peat profile during or subsequent to peat formation but rather reflect the chemical composition of airborne material supplied to the surface layers of the bog at the time of deposition the enrichments of trace metals in ancient peats relative to crustal abundance most likely reflects the natural enrichment of these elements in the fine fraction of soils during rock weathering periods of enhanced soil dust deposition such as the younger dryas cold climate phase 10 590 14 c yr bp are characterized by reduced vegetation cover greater exposed soil surface and higher wind strengths these conditions promote the transport of locally derived soil materials of greater particle size lower concentration of trace metals and m sc ratios approaching crustal values during the holocene climate optimum vegetation cover was extensive and with lower wind strengths and a reduction in erodible soil materials long range transport of soil dust became relatively more important to the soil dust inventory of the bog soil dust particles in this size class are characterized by strong enrichments of a wide range of trace elements at the end of the holocene optimum dust fluxes increased once again due mainly to soil erosion resulting from the combined effects of human activities tillage and the climatic deterioration at the beginning of the neoglaciation period this promoted the supply of local more coarse soil particles with m sc ratios approaching those of crustal rocks while biological cycling and volcanic emissions probably also contributed to the atmospheric supply of many of these elements in the pre anthropogenic past these contributions appear to be less important than the chemical weathering physical fractionation and atmospheric transport of soil dust particles

the monte carrubba formation messinian sicily and its correlatives new light on basin wide processes controlling sediment and biota distributions during the palaeomediterranean mediterranean transition abstract a little known marine miocene messinian succession in the hyblean region of south eastern sicily preserves a carbonate ramp sequence which developed on the tectonically stable foreland margins of the african plate pelagian block the ramp monte carrubba formation was distally steepened and contained a shoalwater barrier and lagoonal inner ramp complex the outer ramp is poorly preserved though distal deep water ramp facies tellaro formation in the south hyblean region preserve a full globorotalia mediterranea subzone and major part of the globigerina multiloba subzone succession this ramp sequence faithfully records the subtle interplay between the global eustatic curve and internal palaeomediterranean base level signatures for the late miocene the earliest second order palaeomediterranean lowstand occurred in the late tortonian at about 7 3 ma and a second occurred at about 6 75 ma within the early messinian g mediterranea subzone both were in the order of 40 m and global sea level was probably restored to the palaeomediterranean after the lowstands although the overriding control at the time was the global eustatic curve harmonic discrepencies between it and the palaeomediterranean curve resulted from constriction of the atlantic connection during the latest tortonian from about 6 4 ma until about 5 96 ma increasingly restricted conditions developed across the monte carrubba inner ramp these faithfully reflect many second order constriction driven palaeomediterranean sea level oscillations which were superimposed on to the falling global signal as the connecting atlantic seaways became constricted these oscillations resulted in major reductions in planktonic faunal diversity within the outer ramp followed by total emergence of the inner ramp by about 6 05 ma marine deposition continued until about 5 96 ma in the southern part of the hyblean region however between 6 05 ma and about 5 6 ma the amplitude of successive palaeomediterranean sea level oscillations increased to over 100 m causing prolonged periods of total palaeomediterranean isolation the hyblean carbonate suite also contains post messinian salinity crisis post msc lago mare highstand deposits which are developed unconformably above the monte carrubba formation the widespread distribution of hyposaline to near marine congeria faunas within the lago mare episode argues for high post msc mediterranean water levels in the central mediterranean late messinian in this article we draw together disparate regional evidence from this stable foreland setting and assimilate it with published data from regions lying on the european plate in order to demonstrate that the tectonically stable monte carrubba succession provides an unambiguous record of central palaeomediterranean base level change during the messinian furthermore the post msc sequence demonstrates a prolonged mediterranean base level rise throughout the late messinian leaving little readjustment necessary in order to restore mediterranean base level to global water levels in basal pliocene times

the significance of messinian occurrences of globorotalia margaritae and globorotalia puncticulata in sicily globorotalia puncticulata and globorotalia margaritae are critical species that define internationally recognized planktonic foraminiferal biozones in the pliocene these biozones are defined from stratotype sections on sicily and their fauna are commonly considered to have been introduced to the mediterranean after an influx of atlantic water that terminated the late miocene desiccation of the basin herein new discoveries of these species in rocks that predate the late miocene desiccation are described these data are supported by magneto and lithostratigraphy that have been integrated at a single continuous section not only do these discoveries question the existing foraminiferal biozone stratigraphy they also suggest new models for the dispersal of planktonic species it is proposed that globorotalia puncticulata and perhaps even globorotalia margaritae evolved in the mediterranean during earliest messinian times during or before chron c3bn1n and dispersed into the atlantic this suggests that a marine connection remained between the two sea areas until at least chron c3an 1n using the existing geomagnetic polarity time scale these occurrences are some 2 myr earlier than previously recorded in the mediterranean the distribution of g margaritae and g puncticulata in mediterranean sections is likely to reflect palaeoenvironment or the preservation of deposits rather than the absolute age of the sediments

seasonal changes in saturn s stratosphere inferred from cassini cirs limb observations abstract we present temperature and hydrocarbons abundances c2h6 c2h2 c3h8 retrieved from cassini cirs limb spectra acquired during northern spring in 2010 l s 12 and 2012 l s 31 we compare them to the previous limb measurements performed by guerlet et al guerlet s et al 2009 icarus 203 214 232 during northern winter the latitudinal coverage from 79 n to 70 s and the sensitivity of our observations to a broad range of pressure levels from 20 hpa to 0 003 hpa allow us to probe the meridional and vertical structure of saturn s stratosphere during northern spring our results show that in the northern hemisphere the lower stratosphere 1 hpa has experienced the strongest warming from northern winter to spring 11 0 9 1 1 k while the southern hemisphere exhibits weak variations of temperature at the same pressure level we investigate the radiative contribution in the thermal seasonal evolution by comparing these results to the radiative convective model of guerlet et al guerlet s et al 2014 icarus 238 110 124 we show that radiative heating and cooling by atmospheric minor constituents is not always sufficient to reproduce the measured variations of temperature depending on the pressure level the measurements of the hydrocarbons abundances and their comparison with the predictions of the 1d photochemical model of moses and greathouse moses j i greathouse t k 2005 j geophys res planets 110 9007 give insights into large scale atmospheric dynamics at 1 hpa c2h6 c2h2 and c3h8 abundances are remarkably constant from northern winter to spring at the same pressure level c2h6 and c3h8 exhibit homogeneous meridional distributions unpredicted by this photochemical model unlike c2h2 this is consistent with the existence of a meridional circulation at 1 hpa as suggested by previous studies

calibrating the duration and timing of the messinian salinity crisis in the mediterranean linked tectonoclimatic signals in thrust top basins of sicily the messinian 9salinity crisis9 which affected the mediterranean represents one of the most dramatic examples of base level fluctuation known in the geological record an amplitude of perhaps 2 km within a stage with a duration of less than 2 ma deposits within the caltanissetta basin of central sicily are used to calibrate the duration and timing of these fluctuations two successions of evaporites termed 9first cycle9 and 9second cycle9 are separated by an inter regional unconformity the first cycle is regionally regressive while the second is transgressive chronostratigraphic calibration of these deposits has been provided by a linked magnetostratigraphic structural and sedimentological study the regression was protracted the earliest evaporites in our study accumulated early in chron c3ar pre 6 88 ma and the youngest accumulated late in chron c3an post 6 0 ma during this interval the basinward shift in coastline was 70 km and in vertical section implies a relative fall in sea level at 0 3 0 4 m ka 1 lowstand probably finally occurred at 5 8 5 5 ma transgression marked by accumulation of the 9second cycle9 deposits which all record reversed magnetizations c3r apparently occurred far more rapidly 200 ka prior to the return to 9normal9 marine conditions in the central mediterranean late in chron c3r local rates of tectonic deformation are relatively slow within the thrust belt which underlies the caltanissetta basin therefore it is likely that the timing and rates of the messinian 9salinity crisis9 on sicily are generally applicable to other basins in the region and help to underpin rates of climate change within this part of the neogene

carbonate deposition and diagenesis in evaporitic environments the evaporative and sulphur bearing limestones during the settlement of the messinian salinity crisis in sicily and calabria abstract the depositional and diagenetic processes involved in the formation of carbonates in the evaporitic environment of the messinian salinity crisis are investigated in southern italy sicily and calabria strong differences are observed between the studied sections that reflect specific depositional and diagenetic evolution in the interconnected sub basins resulting from the syn sedimentary tectonic fragmentation of the central sicilian and calabrian domains these carbonates formed diachronously in restricted perched sub basins between the tripoli formation and the hypersaline settings of the msc the calcare di base cdb that can be interbedded with gypsum layers occurs rhythmically at the transition between the upper part of the tripoli formation and the massive gypsum and at places synchronously with the deposition of the lower gypsum unit it deposited initially as primary peloidal and microbial limestones but their original structure and mineral composition were modified by the superimposition of early to late diagenetic processes the first diagenetic step was the development of interstitially grown gypsum and halite crystals from trapped saturated brines that locally led to the formation of salt beds the sulphur limestone sl resulted from the activity of sulphate reducing bacteria that occurred locally in the deeper parts of the various basins where anoxic bottom waters favoured microbial processes fuelled by biogenic methane and crude oil and caused the carbonate replacement of gypsum and the formation of native sulphur the migration of hydrocarbon and h 2 s rich fluids caused the epigenetic dissemination of sulphur and a late diagenetic carbonate replacement of the gypsum later influxes of continental fresh waters were responsible for the dissolution of the halite crystals and their replacement by sparry calcite the vugs formed during both the gypsum calcite conversion and the halite dissolution either remained empty or were filled with calcite celestine fibrous silica anhydrite secondary gypsum and native sulphur the initial accumulation of fine grained carbonate and gypsum sediments was strongly destabilised by volumetric changes resulting from mineral replacements and fluidisation processes their superimposition explains the vuggy and boxwork like textures in situ brecciation and lateral displacement which are responsible for the chaotic organisation without necessarily involving basin scale re sedimentation in the form of debris flows

late miocene early pliocene stratigraphy and paleoceanography of the south atlantic and southwest pacific oceans a synthesis the stratigraphy and paleoceanography of the late miocene and early pliocene have been examined at six sites in the south atlantic and southwest pacific oceans deep sea drilling project dsdp sites 284 516a 519 588 and 590 and two piston cores from chain cruise 115 a consistent stratigraphy was developed among sites using graphic correlation which resulted in age models for all sites that are tied to the revised paleomagnetic time scale of berggren et al 1985 applying these chronologies we assessed latitudinal and interocean contrasts in the stratigraphic ranges of late miocene early pliocene planktonic foraminiferal and nanno fossil datums salient stratigraphic results include 1 the last appearance datum lad of globoquadrina dehiscens is a late miocene 6 4 ma event in the subtropics and is not useful for the placement of the miocene pliocene m p boundary in this biogeographic province 2 the first appearance datum fad of globorotalia crassaformis occurred at 5 1 ma in the south atlantic near the m p boundary suggesting that gr crassaformis may have first evolved in the south atlantic and later migrated to other regions 3 in the southwest pacific the fads of gr margaritae 5 97 ma gr puncticulata 5 09 ma and gr crassaformis 4 87 ma are significantly time transgressive between temperate and warm subtropical regions time lags of 1 0 m y were required for these species to adapt to physical and or biotic conditions peripheral to their endemic biogeographic provinces 4 between the subtropics of the south atlantic and southwest pacific many planktonic foraminiferal datums fad of dentogloboquadrina altispira gr cibaoensis gr conomiozea gr margaritae and gq dehiscens and lad of gr cibaoensis markedly depart from the correlation suggested by magnetostratigraphy indicating that these datum levels are unreliable for correlation between these ocean basins 5 in contrast available calcareous nannofossil datum levels fall on or near the paleomagnetic correlation line indicating synchroneity of events within the subtropics 6 biostratigraphic magnetic and 87sr 86sr correlation between sites 588 and 519 and the m p neostratotype at capo rossello sicily suggests that the base of the zanclean stratotype occurs at 5 1 5 0 ma in the lower reversed subchron of the gilbert about 2 3 105 years above the gilbert chron 5 boundary oxygen isotopic results from dsdp sites 284 519 and ch115 piston cores confirm a prolonged benthic 18o increase in the latest miocene between 5 6 and 5 0 ma as originally proposed by shackleton and kennett 1975 at dsdp site 588 the benthic 18o record in the latest miocene is marked by high frequency fluctuations with amplitude variations of 0 5 and a long period wavelength component of 400 000 years maximum 18o values however occurred during the late miocene kapitean stage between 5 5 and 5 1 ma the late miocene 18o changes resulted from mid and high latitude cooling and pulses of ice sheet expansion and contraction glacial events were most intense during the latest miocene kapitean stage and occurred at 5 50 5 35 ma and at 5 10 ma glacial events are estimated to have lowered sea level by 40 to 60 m and contributed to the isolation and desiccation of the mediterranean basin during the late messinian interglacial conditions prevailed at 5 2 ma and between 5 0 and 4 1 ma ihe early pliocene the beginning of the pliocene was marked by changes in many proxy climatic indicators at all sites suggesting a prolonged interval of warm interglacial conditions between 5 0 and 4 1 ma during the earliest pliocene supplementary tables are available with entire article onmicrofiche order from american geophysical union 2000florida avenue n w washington dc 20009 documentp86 001 2 50 payment must accompany order

estimation and uncertainty of recent carbon accumulation and vertical accretion in drained and undrained forested peatlands of the southeastern usa the purpose of this study was to determine how drainage impacts carbon densities and recent rates past 50 years of vertical accretion and carbon accumulation in southeastern forested peatlands we compared these parameters in drained maple gum mapl atlantic white cedar cdr and pocosin poc communities in the great dismal swamp national wildlife refuge gds of virginia north carolina and in an intact undrained cdr swamp in the alligator river national wildlife refuge ar of north carolina peat cores were analyzed for bulk density percent organic carbon and 137cs and 210pb an uncertainty analysis of both 137cs and 210pb approaches was used to constrain error at least partially related to mobility of both radioisotopes gds peats had lower porosities 89 6 sd 1 71 versus 95 3 0 18 and higher carbon densities 0 082 0 021 versus 0 037 0 009 g c cm 3 than ar vertical accretion rates 0 10 0 56 cm yr 1 were used to estimate a time period of 84 362 years for reestablishment of peat lost during the 2011 lateral west fire at the gds carbon accumulation rates ranged from 51 to 389 g c m 2 yr 1 for all sites in the drained gds versus intact ar cdr sites carbon accumulation rates were similar with 137cs 87gds versus 92ar g c m 2 yr 1 and somewhat less at the gds than ar as determined with 210pb 111gds versus 159ar g c m 2 yr 1 heightened productivity and high polyphenol content of peat may be responsible for similar rates of carbon accumulation in both drained and intact cdr peatlands

the end of the messinian salinity crisis in the western mediterranean insights from the carbonate platforms of south eastern spain abstract how the messinian salinity crisis msc ended is still a matter of intense debate the terminal carbonate complex tcc is a late messinian carbonate platform system that recorded western mediterranean hydrological changes from the final stages of evaporite deposition till the advent of lago mare fresh to brackish water conditions at the very end of messinian times a multidisciplinary study has been carried out in three localities in south eastern spain to reconstruct the history of tcc platforms and elucidate their significance in the msc overall this study provides evidence that the tcc formed following a regional 4th order water level rise and fall concomitant with an opening restriction trend it can be subdivided into four 5th order depositional sequences ds1 to ds4 recording two phases 1 from ds1 to ds3 a tide dominated ooidic to oobioclastic system with stenohaline faunas developed as a result of a 70 m water level rise during this period the tcc developed in a shallow sea with close to normal marine salinity 2 in depositional sequence 4 a microbialite dominated platform system developed this is indicative of a significant environmental change and is attributed to a 30 to 40 m water level fall in the basins under study these restricted conditions were coeval with intense evaporite deformation and brine recycling the syn sedimentary deformation of evaporites had a major impact on platform architecture and carbonate production affecting the messinian series throughout south eastern spain at the end of the tcc history at that time the tcc developed in a lake with fluctuating brackish to hypersaline water these findings suggest a temporary restoration of marine conditions in the western mediterranean marginal basins due to atlantic water influxes prompted by a global sea level rise around 5 6 ma whether marine conditions extended to the entire western mediterranean still needs to be investigated

stable lead isotope studies of central taurus ore sources and related artifacts from eastern mediterranean chalcolithic and bronze age sites abstract this is the first paper in a series presenting stable lead isotope studies of geological and archaelogical specimens obtained in 7 years of archaeometallurgical surveys in turkey the geological specimens presented here are ore and slag samples taken from ancient mining sites in the central taurus mountain range the archaelogical specimens are metal objects dating to the chalcolithic and bronze ages from anatolia syria mesopotamia greece and the aegean the isotopic measurements on these specimens have been made and statistically analysed as part of a collaborative effort between the smithsonian institution conservation analytical laboratory and the united states national institute of standards and technology nist a comprehensive data base of approximately 1000 stable lead isotope measurements on such eastern mediterranean specimens has been formed by combining the accumulated measurements at nist with analyses published in the literature the overlap between specimens in the overall data bank and the central taurus source specimens provides a realistic evaluations of the effectiveness of the use of stable lead isotope measurements for metallic ore source characterization and for the recognition of exchange patterns of metal and metal artifacts in the formative periods of metallurgy

distribution and origin of lead in stream sediments from small agricultural catchments draining miocene molassic deposits sw france total pb concentrations and isotopic composition were determined in stream bed sediments and bedrock from 29 small agricultural or forested catchments in the gascogne area sw france the contribution of pb from various natural and anthropogenic sources was investigated in this rural area which is very weakly impacted by industrial or urban emissions environmental parameters in catchments importance of forest cover organic matter and oxide content in sediments were considered a combination of geochemical enrichment calculation sequential extraction and isotopic investigations was performed to constrain the origin of pb and the distribution of anthropogenic pb in sediments most of the sediments have low total pb content compared to other agricultural regions more impacted by industrial or urban emissions the results indicated a moderate but significant pb enrichment particularly for catchments draining forested areas this enrichment was positively related to organic c content in sediment and catchment forest cover whereas in entirely cultivated catchments it was related to fe oxide content an average anthropogenic end member was determined using pb isotopes and was supposed to be representative of background atmospheric pb pollution with a weak influence of pb from recent gasoline and local fertiliser spreading the amount of anthropogenic pb pbanthr in sediments estimated using a geochemical approach mean 63 7 20 4 was higher than that estimated using an isotopic approach mean 36 6 17 8 but the same trend was observed among the samples except for low anthropogenic contributions the distribution of pbanthr in sediments from weakly forested catchments indicated a strong affinity for carbonates and fe oxides amorphous fe oxides became preferential trapping compounds as soon as pb enrichment increased and carbonate content decreased finally in cultivated catchments organic c was not a main trapping component for pbanthr in sediments

venus as a more earth like planet venus is earth s near twin in mass and radius and our nearest planetary neighbour yet conditions there are very different in many respects its atmosphere mostly composed of carbon dioxide has a surface temperature and pressure far higher than those of earth only traces of water are found although it is likely that there was much more present in the past possibly forming earth like oceans here we discuss how the first year of observations by venus express brings into focus the evolutionary paths by which the climates of two similar planets diverged from common beginnings to such extremes these include a co2 driven greenhouse effect erosion of the atmosphere by solar particles and radiation surface atmosphere interactions and atmospheric circulation regimes defined by differing planetary rotation rates

a 5500 year proxy climate and vegetation record from blanket mire at talla moss borders scotland a monolith of peat taken from an upland blanket mire at talla moss southern scotland was sub jected to peat humification and pollen analyses to produce both a proxy climate record and a vegetational history covering the last 5500 years while the peat showed little visible stratigraphy with no intimation of major peat humification changes colorimetric data indicate a markedly oscillatory climate record which is apparently largely independent of or out of phase with major vegetational changes the raw data imply particular wet shifts in climate at c 3455 bp c 2600 bp c 1930 bp c 1095 bp with a markedly wet or cool and wet episode commencing at c 540 bp these are central age estimates and should not be regarded as precise dates for the inferred climate shifts other wet shifts apparently date from c 3070 bp c 2265 bp and c 1700 bp although the first of these corresponds with pollen evidence for significant prehistoric human activity in the locality spectral analysis of the peat h

mire development pathways and palaeoclimatic records from a full holocene peat archive at walton moss cumbria england plant macrofossil data have been used to identify the successive mire communities occupying both central and marginal locations in the walton moss peatland complex during the last 10 500 years the reconstructed pathways of mire development indicate that early holocene fen and fen carr communities were succeeded by species indicative of deep mire water tables and oligotrophic conditions the character of the fen bog transition fbt is compared with similar records of peatland development from britain and scandinavia and with independent climate data for the early holocene the pseudohochmoor of central europe is suggested as an approximate modern analogue for the dry pioneer oligotrophic mire type and alternative explanations for its presence are explored the first major increase in ombrotrophic sphagna occurred at c 7800 cal bp overlying sphagnum peats provide a continuous record of climate change inferred from fluctuations in raised mire surface wetness the proxy palaeoclimate record reconstr

late miocene magnetostratigraphy biostratigraphy and cyclostratigraphy in the mediterranean a new chronology for the late miocene of the mediterranean is presented by combining magnetostratigraphic biostratigraphic planktonic foraminifera and dinoflagellates and cyclo stratigraphic data long and continuous upper miocene sections on gavdos metochia section and sicily gibliscemi section display cyclic alternations of homogeneous marls and sapropels and can be correlated on the basis of their distinct cyclic patterns the metochia section yields a good paleomagnetic signal and the position of 17 polarity reversals can be determined the resulting polarity sequence allows an unambiguous correlation to the geomagnetic polarity time scale gpts the paleomagnetic signal in the gibliscemi section is too weak to determine a reliable polarity sequence except for the lowermost part of the section detailed biostratigraphic analysis results in the identification of 13 planktonic foraminiferal and 9 dinoflagellate bioevents which can all be accurately dated the tortonian messinian boundary defined by the first regular occurrence fro of the g conomiozea group is determined in chron c3br 1r with an age of 7 12 ma according to the gpts ck95 of cande and kent 1

isotopic composition of pb in ore deposits of the betic cordillera spain origin and relationship to other european deposits the betic cordillera in southern spain is a complex alpine fold belt that resulted from the cretaceous through cenozoic collision of africa with europe the region is illustrative of one of the characteristics of the alpine mediterranean orogen the occurrence over a limited area of mineral deposits with a wide variety of host rocks mineralization ages and styles the metamorphic basement in the betic zone is characterized by a nappe structure of superimposed tectonostratigraphic units and consists of lower paleozoic to lower triassic clastic metasedimentary rocks this is overlain by middle to upper triassic platform carbonate rocks with abundant strata bound f pb zn ba deposits e g sierra de gador sierra alhamilla cretaceous to paleogene subduction related compression in southeastern spain was followed by miocene postcollisional extension and resulted in the formation of the almeria cartagena volcanic belt and widespread hydrothermal activity and associated polymetallic mineralization typical miocene hydrothermal deposits include volcanic hosted au e g rodalquilar and ag rich base metal e g cabo de gata mazarron deposits as well as complex polymetallic veins mantos and irregular replacement bodies which are hosted by paleozoic and mesozoic metamorphic rocks and neogene sedimentary and volcanic rocks e g cartagena sierra almagrera sierra del aguilon loma de bas lead isotope compositions were measured on sulfide samples from nine ore districts and from representative fresh samples of volcanic and basement rock types of the region the results have been used to evaluate ore forming processes in southeastern spain with emphasis on the sources of metals during a late triassic mineralizing event pb was leached from paleozoic clastic metasedimentary rocks and incorporated in galena in strata bound f pb zn ba deposits 206 pb 204 pb 18 332 or 12 207 pb 204 pb 15 672 or 12 208 pb 204 pb 38 523 or 46 the second episode of mineralization was essentially contemporaneous late miocene throughout the region and did not involve remobilization of less radiogenic triassic ore pb lead isotope data indicate a dominantly paleozoic metasedimentary source for polymetallic vein and manto type deposits that formed by hydrothermal circulation through the betic basement driven by miocene intrusions 206 pb 204 pb 18 747 or 20 207 pb 204 pb 15 685 or 9 208 pb 204 pb 39 026 or 37 lead in au cu te sn ores is isotopically indistinguishable from that of the calc alkalic volcanic host 206 pb 204 pb 18 860 or 9 207 pb 204 pb 15 686 or 8 208 pb 204 pb 38 940 or 27 in contrast the pb in volcanic hosted pb zn cu ag au veins was derived from paleozoic metamorphic and miocene volcanic rocks 206 pb 204 pb 18 786 or 5 207 pb 204 pb 15 686 or 2 208 pb 204 pb 38 967 or 9 a comparison of the pb isotope data from southeastern spain with published data from selected pb zn deposits in southern europe including les malines l argentiere and the alpine iglesiente sulcis and montagne noire districts indicates the importance of a metasedimentary basement as a common source of ore pb

a 3300 year atmospheric metal contamination record from raeburn flow raised bog south west scotland there is now a plethora of records of atmospheric metal deposition across europe based on total concentrations and calculated enrichment factors however to place such records into an archaeological context and to identify anthropogenic contamination signals more accurately it is important to separate the signals derived from anthropogenic activities from those of a natural origin this study presents a new 3300 year record from a bog in the vicinity of hadrian s wall and the northern pennine orefield in order to generate a new atmospheric metal deposition record for this archaeologically important part of the british isles for this purpose multi element geochemistry was undertaken to apportion the contribution of trace metals lead zinc copper arsenic and mercury and sulphur as a result of mining metallurgy and or geogenic processes to extract the different contributions through time we used total concentrations and enrichment factors ef and applied principal component analysis pca to the dataset the pca extracted 7 components at least two components are necessary to elucidate the trace metal distribution zinc arsenic and lead are mostly related to atmospheric pollution while mercury and copper appear to be more closely associated with organic matter based on these results four phases of lead contamination have been identified that date to i c 2350 1500 cal bp ii c 1050 700 cal bp iii c 500 350 cal bp and iv 250 cal bp present copper enrichment also occurs during the bronze age c 3150 2800 cal bp peaks in other metals do not always correspond with lead and they may have been caused by other land use changes or processes that operate internally within the bog although the lead can be attributed to both anthropogenic and geogenic sources its down profile pattern is in accordance with contamination records elsewhere in britain and europe and the lead enrichment recorded at raeburn flow suggests that the northern pennine orefield was exploited for metals during the late iron age and roman period

tertiary and quaternary volcanism in the massif central france summary continental alkaline volcanics of the french massif central range in age from 65 ma to 3450 years bp and can be divided by geography and age into 20 separate areas there is no correlation between the age of an area and the geographic locality two magma series are present a silica undersaturated basanite tephrite phonolite series and an alkali basalt trachyandesite trachyte rhyolite series the evolved members of which are silica saturated rare nephelinites are also found primitive magmas of both main series may be derived from 2 20 partial melting of a mantle enriched with light rare earth elements with variable amounts of garnet in the residue nephelinites were formed from a source which was isotopically and chemically distinct fractional crystallization of observed phases accounts for the diversity of intermediate and evolved products amphibole fractionation in basalts at depth causes the trend towards silica saturation while alkali feldspar fractionation dominates the final stages of crystallization removal of small quantities of sphene and zircon explains trace element depletions in trachytes phonolites and rhyolites up to 30 crustal contamination has occurred in the evolved magmas but contamination is generally absent from their basaltic parents sr nd and pb isotope data indicate that the most probable contaminant is undepleted meta sedimentary granulite facies lower crust variations in sr and nd isotope ratios also constrain petrogenetic hypotheses such as amphibole fractionation and magma mixing mineralogical disequilibrium compositional banding and emulsification textures indicate extensive magma mixing some flows are homogeneous hybrid lavas in which only the unusual composition and rare mineral disequilibria indicate the mode of formation

marine planktic diatom correlation of lower messinian deposits in the western mediterranean abstract samples from late neogene mediterranean outcrops were analysed for diatom content the presence of certain species in the tripoli formation caltanissetta basin sicily and in the beida formation cheliff basin nw algeria permits correlation between these sections and the paleomagnetic reversal record the occurrence ofthalassiosira praeconvexa thalassiosira miocenica thalassiosira convexa var aspinosa andasterolampra acutiloba indicates that the tripoli and beida formations were deposited over an interval ranging from the upper half of paleomagnetic epoch 6 into the lower half of epoch 5 5 6 to 5 9 ma previous diatom correlations were too young the occurrence ofnitzschia reinholdii andasterolampra acutiloba in pre evaporitic diatomites from the upper turre formation se spanish sorbas basin is used to place deposits at this site tentatively in paleomagnetic epoch 5 or 6

the messinian diatomite deposition in the mediterranean region and its relationships to the global silica cycle abstract diatomites constitute a widely represented lithology in the messinian sections of the circum mediterranean neogene marginal basins although traditionally interpreted as genuine evidence of the gradually restricted conditions that characterized the mediterranean just before the messinian salinity crisis their coeval occurrence with a global intensification of the opaline production in the world oceans late miocene early pliocene biogenic bloom suggests that an integrative analysis of the origins of these sediments is necessary a comprehensive analysis of the geological and paleontological records suggests that the synergistic intervention of abiotic tectonic and climate reconfigurations and biotic expansion of grass dominated opal rich biomes controlling factors may have promoted a remarkable enhancement of silica flux from continents to oceans which in turn can explain the opaline burst that occurred during the late miocene at both the global and mediterranean scale the finely laminated pattern and the rich fossil content of diatomaceous deposits that are usually considered to be byproducts of anoxic conditions are briefly discussed some studies seem to indicate that instead of anoxia the aggregation and sedimentation of diatom tests may play a critical role in these processes the lower messinian diatomites of the mediterranean region are generally interbedded with organic rich sediments sapropels clearly attesting prolonged precessionally controlled periods of basin stratification and bottom water anoxia or hypoxia a causal relationship between sapropel and diatomite deposition in the mediterranean is proposed considering the possible interplay between stratification adapted diatoms and anaerobic bacteria and their respective role in influencing the marine silica cycle

saturn s latitudinal c2h2 and c2h6 abundance profiles from cassini cirs and ground based observations abstract hydrocarbons in the upper atmosphere of saturn are known from voyager ground based and early cassini results to vary in emission intensity with latitude of particular interest is the marked increase in hydrocarbon line intensity near the south pole during southern summer as the increased line intensity cannot be simply explained by the increased temperatures observed in that region since the variations between c2h2 and c2h6 emission in the south pole region are different in order to measure the latitudinal variations of hydrocarbons in saturn s southern hemisphere we have used 3 cm 1 resolution cassini cirs data from 2006 and combined this with measurements from the ground in october 2006 at nasa s irtf using celeste an infrared high resolution cryogenic grating spectrometer these two data sets have been used to infer the molecular abundances of c2h2 and c2h6 across the southern hemisphere in the 1 10 mbar altitude region we find that the latitudinal acetylene profile follows the yearly average mean daily insolation except at the southern pole where it peaks in abundance near the equator 5 s the c2h2 abundance at the 1 2 mbar level is 1 6 0 19 10 7 and it decreases by a factor of 2 7 from the equator toward the pole however at the pole 87 s the c2h2 abundance jumps to 1 8 0 3 10 7 approximately the equatorial value the c2h6 abundance near the equator at the 2 mbar level is 0 7 0 1 10 5 and stays approximately constant until mid latitudes where it increases gradually toward the pole attaining a value of 1 4 0 4 10 5 there the increase in ethane toward the pole with the corresponding decrease in acetylene is consistent with southern hemisphere meridional winds greathouse t k lacy j h bezard b moses j i griffith c a richter m j 2005 icarus 177 18 31 the localized increase in acetylene at the pole provides evidence that there is dynamical transport of hydrocarbons from the equator to the southern pole

lead pollution resulting from roman gold extraction in northwestern spain roman mining and metallurgy left a detectable signal of lead pollution throughout europe northern africa and the middle east las medulas in northwestern iberia was the largest roman gold mine

appraising the cohesion of palaeoenvironmental reconstructions in north west spain since the mid holocene from a high temporal resolution multi proxy peat record investigation of abrupt palaeohydrological regime change remains challenging due to site specific noise ratios and the limitations of dating control and spatial resolution of multi proxy records s

environmental change in nw iberia between 7000 and 500 cal bc abstract we review research done on environmental changes in northwest nw iberia spanning from the beginning to the late holocene 7000 500 cal bc the type of archives peat bogs lake sediments colluvium soils etc and proxies pollen element concentrations isotopes etc that were used to reconstruct changes on climate soils vegetation and atmospheric metal pollution are briefly described then we synthesize what the records suggest about the ecological history of nw iberia we identified four main phases 7000 5000 5000 3000 3000 1500 and 1500 500 cal bc each phase is determined by a set of environmental conditions a combination of changes in climate vegetation soils and human impact human activities seem to have been involved in landscape changes in nw iberia since at least 5000 cal bc with an increasing degree of anthropisation through time which accelerated by 1500 cal bc the interaction between human activities and natural changes expressed as modifications in the vegetation cover the elimination of the soil resources in many areas and its concentration in more localized control demanding sectors as well as a progressive acidification and pollution of continental ecosystems to a great extent the present landscape in nw iberia is the end product of these complex interactions a cultural landscape

temperatures winds and composition in the saturnian system stratospheric temperatures on saturn imply a strong decay of the equatorial winds with altitude if the decrease in winds reported from recent hubble space telescope images is not a temporal change then the features tracked must have been at least 130 kilometers higher than in earlier studies saturn s south polar stratosphere is warmer than predicted from simple radiative models the c h ratio on saturn is seven times solar twice jupiter s saturn s ring temperatures have radial variations down to the smallest scale resolved 100 kilometers diurnal surface temperature variations on phoebe suggest a more porous regolith than on the jovian satellites

mobility and diagenesis of pb and 210pb in peat peatlands long have been considered to preserve the record of atmospheric deposition of anthropogenic contaminants such as pb in the past two decades sup 210 pb has been widely used to data recent strata of peat and to calculate accumulation rates the assumption that pb and sup 210 pb are immobile and not subject to diagenesis in peat has been questioned but not rigorously tested the authors attempted to determine if pb is mobile in peatlands and if pb profiles are altered by diagenic processes by constructing a mass balance for pb about a small peatland by comparing inventories concentrations and accumulation rates of pb and sup 210 pb in peatlands across northeastern north america and by examining the relationship between concentrations of pb in bog waters and peat in numerous sites the results clearly demonstrate that pb and sup 210 pb are mobilized by the organic rich waters of peatlands profiles of pb and sup 210 pb at depths below the water table do not preserve the record of atmospheric deposition and inventories of pb and sup 210 pb are depleted in peatland hollows concentrations of pb in bog waters are regulated by the concentration of pb in the peat and the concentration of dissolved organicmore carbon the mass balance for one bog indicated that over the specific three year period of study more than 30 of inputs of pb were not retained within the peat as a result of this mobility dates based on sup 210 pb can be biased and inaccurate by as much as 30 years dates based on sup 210 pb should be verified by other techniques especially when the inventory of sup 210 pb is less than that expected from local rates of deposition less

the sedimentology and development of terravecchia formation carbonates upper miocene of north central sicily possible eustatic influence on facies development abstract on at least two occasions during the late tortonian siliciclastic deposition ceased and carbonates accumulated at the northern margin of the caltanissetta basin in north central sicily bioclastics dominated in the shallower proximal areas while coral reef facies developed where shallow water sand and cobble substrates existed or where sea floor highs has created local shallows the genetic model proposed is that siliciclastic deposition was repeatedly terminated during the late tortonian by rises in sea level which transgressed fluviatile and deltaic environments carbonate deposition was widespread but later erosion and reworking removed much of the sediments except within abandoned delta distributary channels and minor sea floor depressions reef developments associated with channel mouths and the shelf slope break have been preserved in situ whereas channels in more proximal locations are filled with siliciclastic bioclastic and intraclastic rubble from elsewhere on the delta top the wide lateral extent of the truncated tops of the carbonate beds argues for eustatic rather than tectonic controls of erosion and subsequent reworking these events may be closely related in time to other recorded late tortonian eustatic events in the foreland zones such as the hyblean plateau and the maltese islands further south collectively they give some support to a model involving multiple eustatic fluctuations associated with the onset of the messinian desiccation of the mediterranean

eolian inputs of lead to the north pacific we evaluate the importance of natural eolian pb to the dissolved oceanic pb budget by measuring the isotopic composition of pb in 35 holocene and late quaternary sediment samples from the north pacific and in 10 samples of chinese loess when the pacific is divided into sediments provinces based on published end and sedimentological data pb from the central north pacific tends to be the most radiogenic and homogeneous due to the dominance of eolian chinese loess lead from the marginal north pacific and the sparsely sampled regions south of 5 n are less radiogenic and more variable owing to hemipelagic inputs from various volcanic arcs and older continental crust located around the pacific rim 208pb 204pb ratios provide the most distinctive provenance information due to the relatively high ratios in chinese loess the chinese loess samples come from 3 localities and span up to 2 myr of time acetic acid leachate bulk loess and loess silicate fractions were analyzed separately leachate pb is considerably less radiogenic than silicate pb the isotopic composition of the silicate component closely matches the sediment data from the central north pacific confirming the dominance of eolian loess in this region we divided up a suite of published hydrogenous pb isotope data from the pacific ocean according to their locations within the three independently defined sediment provinces these data define three distinct fields differentiated primarily by their 206pb 204pb ratios which increase going from the central to southern to marginal provinces this relationship with sediment province strongly suggests that natural eolian and probably hemipelagic inputs significantly impact the seawater pb budget direct support for the dominance of eolian chinese loess in the central north pacific dissolved pb budget comes from the close match between loess leachate pb and the central province hydrogenous pb data eolian inputs are likely to dominate local seawater pb budgets only where eolian pb fluxes are high relative to hemipelagic pb fluxes and where the flux of pb carried by deep water advection is low

a palaeoenvironmental investigation of sediments from the prehistoric mine of copa hill cwmystwyth mid wales this paper investigates the use of mine sediments to reconstruct the vegetational changes and atmospheric pollution history associated with prehistoric and mediaeval metal mining in the ystwyth valley dyfed mid wales pollen charcoal plant macrofossils fossil insects and chemical analyses are presented from radiocarbon dated sediments contained within a prehistoric mine situated on the upper slope of copa hill close to the village of cwmystwyth the results provide additional support to the hypothesis that prehistoric mining had a negligible impact on woodland and that deforestation took place after bronze age mining ceased although high concentrations of cu pb and zn were determined from sediments of prehistoric and roman age the patterns bear little resemblance to off site atmospheric pollution records and to the archaeological evidence for metal mining interpreting geochemical data from mine contexts is problematic as numerous factors influence the distribution and concentration of metals however an on site and off site approach to investigate human environment interactions caused by metal mining is advocated

the local and global dimensions of metalliferous pollution derived from a reconstruction of an eight thousand year record of copper smelting and mining at a desert mountain frontier in southern jordan abstract this paper establishes an eight thousand year history of anthropogenic metal pollution at one of the oldest most important and longest sustained sites of the extraction and smelting of copper ores in the old world the faynan orefield in jordan which is located between the hyper arid southern desert and the front of the wetter mountains of edom the modern land surface is shown in significant part to be a complex palimpsest of archaeological sites metal pollution of various ages and ore processing deposits quantitative and qualitative observations of the storage and cycling of heavy metals through the local natural and domestic systems have produced a body of information on processes with which the past has been interpreted heavy metal concentrations in semi continuous sedimentary bodies indicate that over the last 1500 years metals were removed by natural processes at a comparatively slow rate given the scale of the original anthropogenic metal burden the proportions of lead with respect to copper have increased as the overall metal burden has been lowered distinctive anthropogenic metal pollution signatures have been detected in ash and charcoal rich deposits that were discarded onto the banks of a perennial stream in the late neolithic at present the nature of the human activities that might have produced these pollution signatures is unknown substantial metal pollution from industrial scale smelting activity was present from the early bronze age the intensity of heavy metal pollution produced in classical times locally exceeded that recorded at major european copper smelting centres in the nineteenth century a d the pollution evidence indicates that intensive copper smelting at the immediate area took place until approximately the end of the byzantine period with the exception of one further minor episode of smelting radiocarbon dated to cal bp 530 330 an observed partial but perhaps significant parallelism is also noted between this local record and the records of the metal burdens of the northern hemisphere determined at mire or ice sheet sites at high altitudes or high latitudes the paper discusses the extent to which this parallelism might be a geochemical indicator of the actual existence of economic systems of a geographical scope and scale to have both exercised substantial pull upon the resources of such isolated and difficult locations at the wadi faynan and to have generated sufficient overall metal pollution to have materially altered the chemistry of the global atmosphere the comparative absence of quantitative information upon the nature spatial scale and impacts of human industrial and natural processes affecting metal pollution in other metal rich arid lands provides a significant impediment to such approaches that seek to research locally and think globally

comment on the biosphere a homogeniser of pb isotope signals by c reimann b flem a arnoldussen p englmaier t e finne f koller and o nordgulen reimann et al 2008 recently published a study on pb isotope signature along a 120 km long transect cutting the city of oslo based on concentration but also isotope data they misinterpret pb concentration of the biosphere in rural places and explain these large enrichments of pb as being due to natural processes the study ignores numerous previous studies either on local regional or global scales see reviews by shotyk and le roux 2005 and callender 2003 and references therein which clearly demonstrate that anthropogenic pb emitted in the atmosphere from different sources leaded gasoline coal burning metallurgy etc was and is dispersed worldwide the study also ignores work on norway by the steinnes and colleagues group harmens et al 2008 steinnes et al 2005a steinnes et al 2005b and aberg et al 2004 and measurements and modelling by the emep network www emep int emep 2005 the study also neglects numerous works on preanthropogenic pb deposition rate and isotopic signature using continental archives of atmospheric deposition like peat bogs shotyk et al 1998 klaminder et al 2003 kylander et al 2005 and le roux et al 2005 these studies have shown that preanthropogenic pb atmospheric deposition rate and its pb isotopic signature is regionally defined but also that those signals are negligible compared to past 2 ka and recent pb atmospheric fluxes table 1

seasonal evolution of saturn s polar temperatures and composition abstract the seasonal evolution of saturn s polar atmospheric temperatures and hydrocarbon composition is derived from a decade of cassini composite infrared spectrometer cirs 7 16 m thermal infrared spectroscopy we construct a near continuous record of atmospheric variability poleward of 60 from northern winter southern summer 2004 l s 293 through the equinox 2009 l s 0 to northern spring southern autumn 2014 l s 56 the hot tropospheric polar cyclones that are entrained by prograde jets within 2 3 of each pole and the hexagonal shape of the north polar belt are both persistent features throughout the decade of observations the hexagon vertices rotated westward by 30 longitude between march 2007 and april 2013 confirming that they are not stationary in the voyager defined system iii longitude system as previously thought tropospheric temperature contrasts between the cool polar zones near 80 85 and warm polar belts near 75 80 have varied in both hemispheres resulting in changes to the vertical windshear on the zonal jets in the upper troposphere and lower stratosphere the extended region of south polar stratospheric emission has cooled dramatically poleward of the sharp temperature gradient near 75 s by approximately 5 k yr coinciding with a depletion in the abundances of acetylene 0 030 0 005 ppm yr and ethane 0 35 0 1 ppm yr and suggestive of stratospheric upwelling with vertical wind speeds of w 0 1 mm s the upwelling appears most intense within 5 latitude of the south pole this is mirrored by a general warming of the northern polar stratosphere 5 k yr and an enhancement in acetylene 0 030 0 003 ppm yr and ethane 0 45 0 1 ppm yr abundances that appears to be most intense poleward of 75 n suggesting subsidence at w 0 15 mm s however the sharp gradient in stratospheric emission expected to form near 75 n by northern summer solstice 2017 l s 90 has not yet been observed so we continue to await the development of a northern summer stratospheric vortex the peak stratospheric warming in the north occurs at lower pressure levels p 1 mbar than the peak stratospheric cooling in the south p 1 mbar vertical motions are derived from both the temperature field using the measured rates of temperature change and the deviations from the expectations of radiative equilibrium models and hydrocarbon distributions solving the continuity equation vertical velocities tend towards zero in the upper troposphere where seasonal temperature contrasts are smaller except within the tropospheric polar cyclones where w 0 02 mm s north polar minima in tropospheric and stratospheric temperatures were detected in 2008 2010 lagging one season or 6 8 years behind winter solstice south polar maxima appear to have occurred before the start of the cassini observations 1 2 years after summer solstice consistent with the expectations of radiative climate models the influence of dynamics implies that the coldest winter temperatures occur in the 75 80 region in the stratosphere and in the cool polar zones in the troposphere rather than at the poles themselves in addition to vertical motions we propose that the uv absorbent polar stratospheric aerosols entrained within saturn s vortices contribute significantly to the radiative budget at the poles adding to the localised enhancement in the south polar cooling and north polar warming poleward of 75

integrated stratigraphy and paleoceanography of the messinian latest miocene across the north atlantic ocean the messinian was a time of major climatic and paleoceanographic change during the late cenozoic it is well known around the mediterranean region because of the giant anhydrite gypsum sequence and the suggested desiccation of the mediterranean sea however this interval is less constrained outside the mediterranean region where several paleoceanographic changes could have taken place because of the desiccation hence we present an integrated stratigraphic framework for future messinian paleoceanographic studies determination of the effect of the mediterranean desiccation on deep water paleoceanography and comparison of intra mediterranean paleoceanographic changes with those in the open oceans during the messinian stage four dsdp odp holes 552a 646b 608 and 547a from the north atlantic ocean and one land borehole from morocco have been studied to integrate bio magneto and stable isotope messinian stratigraphy with high resolution sampling our results produce the best assessment of the tortonian messinian boundaries in all holes because they do not rely on any one signal in paleomagnetic subchronozone csan lr in the sale borehole and dsdp site 609 a s d coiling direction change of neogloboquadrina pachyderma acostaensis appears to indicate pmow entering the northeastern atlantic ocean at least reaching 50 n diachrony and synchrony of some important messinian planktic foraminifera from these atlantic dsdp odp holes and the sale borehole such as the lo of gq dehiscens the lo of gt lenguaensis the fo and lo of gt conomiozea the fo of gt margaritae s s the fo of gt puncticulata and the fo of gt crassaformis are discussed for understanding some of the paleoceanographic changes this integrated stratigraphie framework presented here allows much better north atlantic correlations at this critical point in messinian geologic history

atmospheric deposition and isotope biogeochemistry of zinc in ombrotrophic peat abstract zinc isotope ratios were measured in the top sections of dated ombrotrophic peat cores in finland to investigate their potential as proxies for atmospheric sources and to constrain post depositional processes affecting the geochemical record the peat deposits were located in hietajarvi a background site well away from any point pollution source and representing background conditions in outokumpu next to a mining site and in harjavalta next to a smelter measured total concentrations calculated excess concentrations and mass balance considerations suggest that zinc is subjected to important biogeochemical cycling within the peat significant isotopic variability was found in all three peat bogs with heavier zinc in the deeper and lighter zinc in the upper sections isotope ratios and concentrations correlated in the two peats located next to dominant point sources i e the smelting and mining site suggesting that zinc isotopes trace pollution sources concentration and isotope peaks were offset from the period of mining and smelting activity supporting migration of zinc down the profile the 66znjmc where 66zn 66zn 64zn sample 66zn 64zn jmc standard 1 103 of the top section sample at the remote hietajarvi site was 0 9 and we suggest this represents the regional background isotope signature of atmospheric zinc the deeper sections of the peat cores show isotopically heavier zinc than any potential atmospheric source indicating that post depositional processes affected the isotopic records the large variations encountered up to 1 05 for 66zn and rayleigh modelling imply that multiple fractionation of zinc during diagenetic alterations occurs and nutrient recycling alone cannot explain the fractionation pattern we propose that zinc isotopes are amenable to identify different atmospheric zinc sources including zinc derived from anthropogenic activities such as mining and smelting but multiple biogeochemical processes seriously affect the record and they need to be evaluated and assessed carefully if zinc isotopes are used in terrestrial paleorecords

eustatic implications of late miocene depositional sequences in the melilla basin northeastern morocco abstract the age 5 78 ma or lower chron c3r of the major drawdown of the paleo mediterranean sea during the messinian salinity crisis has been established by combining results from stratigraphy paleontology magnetostratigraphy and argon dating for a late miocene sedimentary succession in the melilla basin ne morocco this event is inferred from a marine to continental series of carbonate and siliciclastic rocks that record the end of messinian marine deposition in the melilla basin and presumably marks the final isolation of the paleo mediterranean sea the evidence from the melilla basin is approximately coeval with an increase in benthic foraminiferal 18 o values from a deep marine section in the bou regreg valley nw morocco hodell et al 1994 this increase suggests that a glacio eustatic lowering of sea level at least contributed to the final closure of the mediterranean during the messinian salinity crisis the marine to continental succession onlaps a carbonate complex that contains evidence for multiple relative sea level changes leading up to the main drawdown from bottom to top the carbonate complex is composed of 1 an onlapping ramp 2 a prograding bioclastic platform 3 a prograding and locally downstepping porites reef complex and 4 a topography draping sequence composed of grainstones porites reefs and stromatolites terminal carbonate complex of esteban 1979 the transgressive ramp correlates to relatively low values of benthic foraminiferal 18 o values from a tortonian to lower messinian section at bou regreg hodell et al 1994 this correlation indicates at least in part a link between rising sea level and a reduction in global ice volume during deposition of the ramp a major fall in relative sea level 60 m occurred near the demise of the reef complex during chron c3n 1n at 5 95 0 10 ma this signals the initiation of drawdown and changing environmental conditions in the melilla basin a marginal basin and perhaps the entire paleo mediterranean sea a megabreccia interpreted as forming by solution collapse of evaporites on the basin margin of the reef complex occurs at the base of the terminal carbonate complex updip a major subaerial unconformity separates the reef complex and terminal carbonate complex evaporite deposition likely occurred during this exposure event and has been dated at 5 82 0 02 ma near the base of chron c3r we contend that these evaporites restricted to the shallow melilla basin are related to the continuation of the initial stage of the major drawdown of the paleo mediterranean sea

the age of the tortonian messinian boundary the tortonian messinian boundary is marked by the first occurrence datum fod of globorotalia conomiozea which is found all over crete in open marine marls with good palaeomagnetic properties within the framework of the miomar project the previously studied sections of langereis et al 1 have been extended and partly resampled here we present new magnetostratigraphic and biostratigraphic results from sections on eastern crete faneromeni central crete kastelli and western crete potamida and skouloudhiana supplemented by cyclostratigraphic data the recently developed geomagnetic polarity time scale ck92 of cande and kent 2 allows an unambiguous correlation of the polarity sequences on crete the fod of g conomiozea occurs in the reversed interval of anomaly c3bn lr this leads to a new age determination of 6 92 ma for the tortonian messinian boundary and a duration of 1 76 myr for the messinian a slightly modified version of ck92 if we use more recent age estimates provides an age of 7 10 ma and a duration of 1 78 myr respectively bipartite sedimentary cycles are distinctly present in the cretan sections studied assuming that these cycles are precession induced and using an average periodicity of 21 7 kyr enables us to independently estimate the duration of the successive individual polarity zones the astronomically derived durations of the cretan polarity zones are in good agreement with ck92 but are approximately 10 shorter

particle size fractionation of titanium and zirconium during weathering and pedogenesis of granitic rocks in nw spain abstract titanium and zr were analyzed in 10 weathering and pedogenetic soil profiles developed on granitic rocks from nw spain concentrations were obtained by xrf and the ti and zr bearing minerals were studied by petrographical sem and eds analysis both elements were measured in rock bulk soil and granulometric fractions sand 2000 50 m silt 50 2 m clay titanium concentrations in the rock varied between 0 5 and 4 2 g kg 1 and zr concentrations from 52 to 173 mg kg 1 concentrations in bulk soil for the different horizons remain almost unchanged and are strongly related to the element content of the parent rock in some epipedons ti content is relatively lower than that of the underlying horizons due to a dilution effect caused by the high organic matter content and the addition of fresh minerals from erosion upslope the mineralogical study revealed that zr is present exclusively in zircons while ti occurs in rutile ilmenite and titanite but mainly as a structural component of the biotite regarding the particle size fractions both elements behave differently zirconium is enriched in the silt fraction of all soil horizons with concentrations up to 5 times that of the parent rock while ti is enriched in the silt up to 5 times and clay fractions up to 12 times of the solum horizons and depleted in the sand fraction of the a horizons these results indicate that zr concentrations are mainly controlled by the abundance of zircons in the rock and their physical detachment from the host minerals upon weathering ti mainly depends on the release from the structure of biotites through chemical weathering and its reprecipitation as neoformed mineral phases this physicochemical fractionation of ti and zr in soils bears important implications for studies on soil genesis continuity of soil profiles and the calculation on enrichment factors which are based on the conservative behaviour of both elements

a 14 500 year record of the accumulation of atmospheric mercury in peat volcanic signals anthropogenic influences and a correlation to bromine accumulation a 14 500 calendar year record of mercury accumulation rates has been obtained from an ombrotrophic peat bog in the swiss jura mountains the range of natural pre industrial mercury accumulation rates varied from 0 3 to 8 0 w gm 32 yr 31 during the late glacial and holocene climatic and volcanic signals were evident in the mercury record mercury accumulation rates increased by a factor of ca 5 during the younger dryas cold period short term spikes in mercury accumulation rates which correspond in time to known volcanic eruptions occur during the late boreal and older atlantic periods when volcanic influences on mercury deposition appear to have been intensified due to increased atmospheric humidity a correlation of mercury to bromine accumulation is observed throughout the preanthropogenic period during the holocene mercury accumulation only exceeded the range of this correlation for a few short periods of elevated mercury deposition which correspond to known volcanic eruptions during the older atlantic during historical times mercury accumulation rates have exceeded the range of the correlation of mercury to bromine continuously since ca 1330 ad this excess in mercury accumulation is interpreted as an indication of pollution during the industrial period mercury accumulation rates reached 107 6 w gm 32 yr 31 of which 84 was mercury that exceeded the correlation range mercury accumulation rates peaked again during the 1970s with 78 8 wg m 32 yr 31 early 20th century pollution appears to have been dominated by non swiss emissions from coal burning whereas swiss mercury emissions appear to have been the dominant pollution source during the mid and late 20th century current mercury accumulation rates at the site are similar to those ca 10 years ago with modern deposition rates being ca 15 times their prehistorical average anthropogenic emissions of reactive brominated compounds could be contributing to increased atmospheric deposition rates of mercury a 2002 elsevier science b v all rights reserved

ancient copper and lead pollution records from a raised bog complex in central wales uk this paper presents records of metal deposition as preserved by a peatland which has accumulated in the lowland coastal zone at borth near aberystwyth ceredigion mid wales u k the research objective was to explore the origins and history of metal mining and or metallurgy by reconstructing a geochemical record of copper lead and zinc pollution for the last four millennia two cores were extracted from borth bog one from the raised ombrotrophic part of the bog and another from a minerotrophic part of borth bog close to the ancient copper workings at llancynfelin although peat stratigraphy and nutrient status have influenced the geochemical record the results suggest that an early phase of copper and lead pollution occurred at llancynfelin whilst lead enrichment occurred in the peat core taken close to the centre of borth bog during the bronze age and the roman occupation therefore the origins of copper and lead mining and metallurgy possibly extend back to the bronze age in central wales no record of historical pollution exists at either site the results of this study also provide further evidence that lead and copper are immobile in ombrotrophic peat and that pollution records can be elucidated from minerotrophic peat zinc however may have suffered from post depositional mobility

efficiency of neutrino induced radio measurements to inspect local areas of enceladus abstract the cassini probe observed a young and smooth surface around the south pole of enceladus while around the north pole the surface was found to be relatively old and inactive porco c c et al 2006 science 311 1393 1401 this heterogeneous surface implies that the ice thickness of enceladus is not uniform between the north and south polar regions determining the thickness of the icy layer is important to confirm the existence of an internal ocean as well as to reveal the heating mechanism of enceladus we show that the measurement of radio waves induced by cosmic neutrinos can be an effective method to constrain the ice thickness of a localized area where conventional gravity or electromagnetic field measurements cannot be used this method could be used to constrain the thickness of the icy layer on enceladus even if the ice is a few tens of kilometers thick measuring over a period of several years which greatly exceeds the ability of radar sounding and hence could be used in future orbiter missions

petrostratigraphic analysis of a late miocene mixed siliciclastic carbonate depositional system calabria southern italy implications for mediterranean paleogeography abstract mixed siliciclastic carbonate sediments are common in shallow water environments in which clastic deposition and carbonate production coexist in the mediterranean basin the tortonian messinian sedimentary successions are commonly comprised of marls alternations of marls with diatomites sands and sandstones limestones especially algal and coral reefs and evaporites most of the studies in the mediterranean basin have been focused on carbonate facies analysis whereas the siliciclastic portions are poorly described similarly to the other marginal settings of the mediterranean basin the capo vaticano area southern calabria southern italy experienced mixed sedimentation at that time petrological analysis was performed on 56 weakly cemented sandstones linking compositional signatures to stratigraphic data with the aim of investigating sedimentary response to the tortonian messinian transgression and its influence on the carbonate production the information obtained is used to refine the regional sediment dispersal pathways and paleogeography by means of bio stratigraphic evidence the studied succession to coeval mixed deposits dislocated in the mediterranean basin is correlated

a new geomagnetic polarity time scale for the late cretaceous and cenozoic we have constructed a magnetic polarity time scale for the late cretaceous and cenozoic based on an analysis of marine magnetic profiles from the world s ocean basins this is the first time since heirtzler et al 1968 published their time scale that the relative widths of the magnetic polarity intervals for the entire late cretaceous and cenozoic have been systematically determined from magnetic profiles a composite geomagnetic polarity sequence was derived based primarily on data from the south atlantic anomaly spacings in the south atlantic were constrained by a combination of finite rotation poles and averages of stacked profiles fine scale information was derived from magnetic profiles on faster spreading ridges in the pacific and indian oceans and inserted into the south ariantic sequence based on the assumption that spreading rates in the south atlantic were smoothly varying but not necessarily constant a time scale was generated by using a spline function to fit a set of nine age calibration points

correlations and sequence stratigraphic model for messinian carbonate platforms of the western and central mediterranean distance correlations of late tortonian messinian littoral carbonate complexes are proposed from the study of eight platforms in the western and central mediterranean correlations are based on the identification of two major biological sedimentary cycles and of two index surfaces surface a is a maximum flooding surface during cycle 1 at around 6 7 ma surface b is a regional marine planation surface at around 5 95 ma at the base of cycle 2 terminal carbonate complex a general sedimentary model is proposed for the 7 5 6 ma time span the boundary between cycles 1 and 2 is coincident with the onset of the messinian salinity crisis and appears to be related to major environmental paleo oceanographic changes in the mediterranean rather than to a major sea level drop or to climatic change

late holocene sea level changes in eastern quebec and potential drivers abstract late holocene sea level changes can be reconstructed from salt marsh sediments with decimetre scale precision and decadal scale resolution these records of relative sea level changes comprise the net sea level contributions from mechanisms that act across local regional and global scales recent efforts help to constrain the relative significance of these mechanisms that include sediment dynamics and isostasy which cause relative sea level changes via vertical land motion ocean atmosphere processes that influence regional scale ocean mass redistribution and ocean cryosphere and steric interactions that drive global scale ocean volume changes there remains a paucity of high resolution late holocene sea level data from eastern canada this precludes an interrogation of the mechanisms that define sea level changes over recent centuries and millennia in a region sensitive to oceanic atlantic multidecadal variability atlantic meridional overturning circulation atmospheric north atlantic oscillation arctic oscillation and cryospheric ice mass balance changes we present new relative sea level data that span the past three millennia from baie des chaleurs in the gulf of st lawrence generated using salt marsh foraminifera supported with plant macrofossil analyses the accompanying chronology is based on radiocarbon and radionuclide analyses which are independently verified using trace metal and microcharcoal records relative sea level has risen at a mean rate of 0 93 1 25 mm yr 1 over the past 1500 years residual structure within the reconstruction internal variability has contributed up to an additional 0 61 0 46 mm yr 1 of short lived rsl rise prior to 1800 ce following a sea level low stand during the little ice age acceleration in relative sea level rise is identified between 1800 and 1900 ce within the estimates of internal variability and from 1950 ce to present in both the secular and residual trends phases of relative sea level changes in the gulf of st lawrence are concomitant with periods of glacier mass loss following the little ice age phase periods of the north atlantic oscillation and the atlantic meridional overturning circulation and northern hemisphere warming quantifying the individual effects of these different mechanisms is important for understanding how ocean atmosphere processes redistribute ocean mass upon larger scale background ocean volume changes

isotopic trends and background fluxes of atmospheric lead in northern europe analyses of three ombrotrophic bogs from south sweden isotopic trends and background fluxes of atmospheric lead in northern europe analyses of three ombrotrophic bogs from south sweden

is there a chronological record of atmospheric mercury and lead deposition preserved in the mor layer o horizon of boreal forest soils the organic horizon the mor layer of podzolized boreal forest soils has accumulated atmospheric fallout of mercury and lead over centuries resulting in current concentrations close to levels whe

4 500 year old mining pollution in southwestern spain long term implications for modern mining pollution the tinto river drains the rio tinto mining district which comprises the world s largest known massive sulfide deposits these orebodies have been mined from the third millenium bc to the present the tinto river is strongly acidic ph 1 5 2 5 during flood events it transports a sandy material including abundant detrital pyrite grains a core drilled in the holocene sediments of the tinto estuary allows for investigation of recent and historical mining pollution two anomalous horizons have been recognized 0 1 3 m 3 4 m both are characterized by very high metal content 100 times over the background and by the presence of abundant clastic pyrite grains the metal association pb ba as cu zn sn tl cd ag hg au is typical of that of the rio tinto pyritic ore the upper horizon corresponds to the modern mining activity the lower horizon has been dated at 2530 bc 14c ams calibrated age we show here that active mining occurred early copper age in the rio tinto area resulting in a watershed scale metal contamination we also show that anthropogenic input of metals may be accumulated and immobilized during thousands of years in estuarine sediments

asian provenance of glacial dust stage 2 in the greenland ice sheet project 2 ice core summit greenland samples of dust from the greenland ice sheet project 2 gisp2 ice core summit greenland dated within marine isotope stage 2 between 23 340 and 26 180 calendar years b p around the time of the coldest local last glacial temperatures have been analyzed to determine their provenance to accomplish this we have compared them with approximately coeval aeolian sediments mostly loesses sampled in possible source areas psas from around the northern hemisphere the 5 m grain size fraction of these samples was analyzed on the basis that it corresponds to the atmospheric dust component of that time and locale which was sufficiently fine grained to be transported over long distances on the basis of comparison of the clay mineralogy and sr nd and pb isotope composition with ice dust and psas and assuming that we have sampled the most important psas we have determined that the probable source area of these gisp2 dusts was in eastern asia the dust was not derived from either the midcontinental united states or the sahara two more proximal areas that have been suggested as potential sources based on atmospheric circulation modeling except for a brief period during an interstadial when dust transport was exceptionally low for glacial times and had a mineralogical composition indicative of a slightly more southern provenance the source area of the dust did not change significantly during times of variably higher fluxes of dust with larger mean grain size or lower fluxes of dust with smaller mean grain size this includes the high dust period that correlates with the heinrich 2 period of major iceberg discharge into the north atlantic variable wind strengths must therefore be invoked to account for these abrupt and significant changes in dust flux and grain size

five thousand years of atmospheric ni zn as and cd deposition recorded in bogs from nw iberia prehistoric and historic anthropogenic contributions abstract the analysis of environmental archives from across the world has demonstrated that human perturbation of the geochemical cycles of trace metals and the resultant atmospheric metal contamination date back at least several millennia however an understanding of the local processes and timing of changes in trace metal deposition is also essential for a proper global interpretation the iberian peninsula was a major mining area since prehistoric times and the analysis of environmental archives provides a good opportunity to improve our understanding of the history of mining and metallurgy in europe we present the results from three 14 c dated peat cores from the xistral mountains nw iberia these records are used to reconstruct past atmospheric deposition of ni zn as and cd the chronology of the changes in concentrations and metal accumulation rates was found to be concordant in the three bogs and showed great similarity to total pb hg and pb isotope ratios as determined in previous investigations they present a consistent view of changes in atmospheric pollution and the importance of metals in the development of human societies especially i the first evidence of atmospheric metal pollution 3400 years ago which is simultaneous with the expansion of the atlantic bronze koine ii a pollution event between 2350 and 2150 years ago associated to the development of so called celtic culture local late iron age iii a dramatic increase of metal fluxes in roman times iv a severe and rapid increase in the last 250 years corresponding to the beginning of the industrial revolution in europe reflecting the emergence of the new dominant sources of pollution and v the increase of long range atmospheric transport of pollutants our data suggest that all detected ancient until ca 1450 cal bp periods of enhanced ni zn as and cd accumulation may have had an anthropogenic origin related to the onset and development of mining and metallurgy

magnetostratigraphy and paleontology of ait kandoula basin high atlas morocco and the african european late miocene terrestrial fauna exchanges abstract a magnetostratigraphic study has been carried out on a middle miocene to upper pliocene lacustrine sedimentary deposit in the central part of the ait kandoula basin which contains micromammal faunas and is situated in the southern high atlas morocco in total 113 samples were subjected to paleomagnetic analysis 60 out of the 113 studied samples representing 52 different stratigraphic levels yielded a paleomagnetic direction and at least the polarity could be recognized in 42 specimens eleven specimens were submitted to af demagnetization the mean direction for normal polarity samples was d 349 4 i 50 7 n 36 95 4 5 k 27 and for reversed polarity samples d 191 2 i 53 4 n 16 95 12 32 k 9 these results yielded a polarity sequence which we interpret as spanning from chron c5n 2n to the beginning of chron c3n 4n this interpretation relies on biostratigraphic data previously proposed for a part of the continental fauna found in the basin this result is in agreement with the 40ar 39ar dating previously carried out on a volcanic ash layer which provided an age of 5 9 0 5 ma 1 and which is shown here to be reversely magnetized this layer is correlated here with the reverse polarity zone corresponding to chron c3r biostratigraphic studies on the same section have shown that the micromammal levels extend here only from middle vallesian to upper turolian upper miocene four localities have yielded western european species of micromammals indicating trans mediterranean terrestrial faunal exchanges between these two continents during the late miocene the european murid rodent occitanomys is recorded for the first time in north africa in level 8 of the afoud section an age younger than 5 32 ma being assigned to this level by the present study level 1 of the same section yields the lagomorph prolagus cf michauxi with an age of 6 1 ma the magnetostratigraphic data suggest therefore that the beginning of terrestrial faunal exchanges between north africa and western europe took place in subchron c3an 1n at about 6 1 ma some 0 4 myr before the beginning of the messinian salinity crisis

linking changes in atmospheric dust deposition vegetation change and human activities in northwest spain during the last 5300 years a high resolution 5300 yr record of pollen and lithogenic elements k ca ti rb sr y zr from an ombrotrophic peat bog located in northwest spain reveals that the variations in the fluxes of lithogenic elements supplied to the bog by atmospheric deposition were coupled to the evolution of the vegetation of the area a strong negative correlation exists between the percentage of tree pollen and the concentration of lithogenic elements for example the correlation between total tree pollen and sr concentrations is 0 94 the main phases of decline of the deciduous forest occurred during known cultural periods late neolithic the metal ages the roman period the middle ages and the industrial period suggesting a close link between human activities fires and forest clearances changes in the vegetation and soil erosion the flux of lithogenic elements seems to have increased before a significant variation in pollen is detected which may indicate that changes in soil erosion are reflected earlie