cyclic climate and vegetation change in the late miocene of western bulgaria abstract a late miocene paludal to lacustrine sequence from a carbonate basin in nw bulgaria staniantsi basin is analysed displaying up to 27 rhythmically bedded sedimentary cycles in the lower part of the sequence the cycles consist of alternating autochthonous brown coal and marls containing diverse mollusc assemblages the upper part of the sequence is characterized by alternating dark to light grey clays and calcareous silts a palynomorph record comprising 163 samples is analysed by statistical means to reconstruct vegetation changes the coexistence approach is used to calculate quantitative palaeoclimate records for 6 parameters the studied section displays hierarchical cyclicity patterns longer term cycles possibly related to eccentricity period 100 kyr are present in the palynomorph record and show climate changes of warmer wetter and cooler drier periods in combination with frequency oscillations of thermophilous elements short term cycles most probably related to precession period 21 7 kyr are expressed by alternations of brown coal and marl shell beds and show cyclic change in peat forming vegetation related to oscillations of the groundwater level as a triggering mechanism wetter warmer and drier cooler climate phases related to orbital precession are probable in addition sections sampled at high resolution display small scale climate and vegetational variability as is shown by the analysis ferns were an important component of the peat forming vegetation while outside the mire a wetland vegetation consisting of pioneers and a mixed mesophytic forest with evergreen shrubs existed an oligo to mesotrophic slightly alkaline lake became repeatedly established with a diverse mollusc fauna and a dense hydrophytic vegetation with characean meadows in the upper part of the section a spreading of herbaceous vegetation is observed also known from other contemporaneaous palynomorph records in bulgaria and surrounding areas the increase of asteraceae in the upper part of the section combined with a marked decrease in woody taxa points to an opening of habitats and a decrease in mean annual precipitation this trend is paralleled by the mollusc fauna which yields several terrestrial partly xerophilous taxa

delineation of shallow resistivity structure in the city of burdur sw turkey by vertical electrical sounding measurements the city of burdur which is built on an alluvium aquifer is located in one of the most seismically active zones in southwestern turkey the soil properties in the study site are characterized by unconsolidated and water saturated sediments including silty clayey and sandy units and shallow groundwater level is the other characteristic of the site thus the city is under soil liquefaction risk during a large earthquake a resistivity survey including 189 vertical electrical sounding ves measurements was carried out in 2000 as part of a multi disciplinary project aiming to investigate settlement properties in burdur city and its vicinity in the present study the ves data acquired by using a schlumberger array were re processed with 1d and 2d inversion techniques to determine liquefaction potential in the study site the results of some 1d interpretations were compared to the data from several wells drilled during the project also the groundwater level map that was previously obtained by hydrological studies was extended toward north by using the resistivity data 2d least squares inversions were performed along nine ves profiles this provided very useful information on vertical and horizontal extends of geologic units and water content in the subsurface the study area is characterized by low resistivity distribution 150 m originating from high fluid content in the subsurface lower resistivity 3 30 m is associated with the quaternary and the tertiary lacustrine sediments while relatively high resistivity 40 150 m is related to the quaternary alluvial cone deposits this study has also shown that the resistivity measurements are useful in the estimation of liquefaction risk in a site by providing information on the groundwater level and the fluid content in the subsurface based on this we obtained a liquefaction hazard map for the study area the liquefaction potential was classified by considering the resistivity distributions from 2d inversion of the ves profiles the types of the sediments and the extended groundwater level map according to this map the study area was characterized by high liquefaction hazard risk

late miocene to early pliocene depositional history of the intramontane florina ptolemais servia basin nw greece interplay between orbital forcing and tectonics abstract upper miocene and lower pliocene shallow lacustrine deposits from the florina ptolemais servia basin in northwest greece show a distinct m scale sedimentary cyclicity of alternating marls and lignites or clays which were shown to be primarily related to precession induced climate variations van vugt n steenbrink j langereis c g hilgen f j meulenkamp j e 1998 magnetostratigraphy based astronomical tuning of the early pliocene lacustrine sediments of ptolemais nw greece and bed to bed correlation with the marine record earth planet sci lett 164 3 4 535 551 steenbrink j van vugt n hilgen f j wijbrans j r meulenkamp j e 1999 sedimentary cycles and volcanic ash beds in the lower pliocene lacustrine succession of ptolemais nw greece discrepancy between 40ar 39ar and astronomical ages palaeogeogr palaeoclimatol palaeoecol 152 283 303 steenbrink j van vugt n kloosterboer van hoeve m l hilgen f j 2000 refinement of the messinian apts from sedimentary cycle patterns in the lacustrine lava section servia basin nw greece earth planet sci lett 181 3 4 161 173 three additional sections and drill cores from the same basin are studied using a combination of cyclostratigraphy magnetostratigraphy and 40ar 39ar dating together with the earlier studied sections they provide a continuous succession that documents the depositional history of the intramontane neogene basin fill sedimentation in the basin started at around 8 ma ago with deposition of coarse grained terrigenous clastics in an alluvial environment from 7 1 to 6 1 ma ago diatomaceous marls were deposited in a lacustrine environment frequently interrupted by deposition of clays and local xylite type lignite seams hereafter deposition of alternating coarse and fine grained terrigenous clastic alluvial sediments took place followed by a gradual shift towards lacustrine sedimentation at around 5 5 ma deposition of alternating fine grained clastics silts and clays and biochemical sediments carbonates marls and thin lignites with episodic periods of sub aerial exposure continued until 5 23 ma from then onwards up to 3 9 ma regular alternating lignites and marls were formed in a shallow lacustrine environment precession induced fluctuations of regional climate primarily defined the m scale variations in lithology as observed in all members of succession whereas the 100 and 400 kyr eccentricity cycle had a clear impact on larger scale lithological alternations in parts of the succession as well a marked similarity in the ages of fundamental changes in depositional environments between the florina ptolemais servia basin and the marine basins in the mediterranean is observed suggesting but not necessarily implying that they have a common possibly tectonic origin

the 1971 may 12 burdur earthquake sequence sw turkey a synthesis of seismological and geological observations summary it is now widely accepted that the rapid extension observed in western turkey is mainly accommodated by large active normal faults which control the geomorphology the ne sw trending burdur acigol and baklan basins bounded by large faults form a system of half graben whose orientation is evident in both the topography and the tilting of neogene sediments adjacent to them we used long period p and sh waveforms to determine the source parameters of the two largest earthquakes of the 1971 may 12 sequence that occurred in the burdur region the main shock was followed by many aftershocks which were distributed in a broad zone elongated ne sw parallel to the long axes of the basins in the region documented surface breaks of the 1971 event suggest that the northwest dipping faults along the southern margin of the burdur basin are those which moved well exposed fault planes are found dominantly to the south of burdur lake the surface dips of these faults are greater than that of the nw dipping nodal plane obtained for the main shock combined seismological and geological observations suggest that these faults have listric geometries

diastasis cracks mechanically generated synaeresis like cracks in upper cambrian shallow water oolite and ribbon carbonates upper cambrian limestones and dolostones of western newfoundland canada display conspicuous synsedimentary mud cracks cracks occur in carbonate mudstone interbedded with ooid and peloid grainstone unwashed oolite and ribbon rock lithofacies the traditional interpretation is that these are desiccation cracks the weight of evidence supports an alternative e explanation cracks resulted from the differential mechanical behaviour under stress of stiff mud interlayered with loose ooid peloid sand the processes envisaged to cause such diastasis cracks may be applicabl e to a wide variety of both carbonate and terrigenous clastic deposits composed of interlayered sediments of contrasting material properties and may be a viable alternative to synaeresis

paleoelevations in the jianchuan basin of the southeastern tibetan plateau based on stable isotope and pollen grain analyses abstract the southeastern margin of the tibetan plateau tp is a key region for understanding the region s surface uplift mechanisms this study focused on the jiuziyan and shuanghe formations fms in the jianchuan basin both of which include lacustrine calcareous mudstones and marls ostracods of the genus austrocypris found within the jiuziyan and shuanghe fms constrain the age of strata to the late eocene this study used two different proxies i e fossil pollen coexistence and the 18o vpdb values of carbonate 18oc to reconstruct paleoelevation and the extant paleoenvironment from lacustrine calcareous mudstones and marls preserved in the eocene stratigraphy of the jianchuan basin the coexistence approach ca using pollen data from the shuanghe fm indicates a paleoelevation of 1 3 2 6 km above sea level asl which would most probably have been associated with a vegetation cover consisting of tropical subtropical deciduous coniferous broadleaf forests the reconstructed mean annual air temperature maat had a value of 16 8 21 7 c warmer than today s maat 6 c oxygen isotope results from the jiuziyan fm with without modification between eocene and modern myanmar sea level suggested that the surface of the jianchuan basin was at a paleoelevation between 0 5 0 8 0 5 km asl and 2 5 0 7 km asl 18omw 8 9 1 3 2 during the shuanghe fm sedimentation the paleoelevation was between 0 9 0 7 0 7 km asl and 2 9 0 6 km asl 18omw 9 5 1 1 2 our results suggest that a stepwise uplift of jianchuan basin and crustal thickening initiated during the eocene was the cause of passive surface uplift of the southeastern tibetan plateau tp rather than miocene lower crustal flow

late neogene continental stages in nw europe revisited pollen records from fluvial deposits in the netherlands have traditionally been used to establish continental stages for the neogene in nw europe these stages are still widely used across europe for stratigraphic correlations and palaeoclimatic studies despite their extensive use the validity of this continental correlation scheme for the plio and pleistocene has never been tested in the area where they were originally proposed the roer valley graben rvg the fluvial and deltaic depositional setting in this area is controlled by a complex pattern of tectonic and climatic processes which strongly complicates the definition of stages and sub stages of regional or supra regional significance here the original palynological data used to define the praetiglian reuverian brunssumian susterian and linne sub stages are assessed and compared to new borehole data with a multivariate correspondence analysis approach we show that most of these stages cannot be distinguished by numerical analysis of the pollen assemblages a tripartition of pollen assemblages is possible which results in a cooler pleistocene cluster warm temperate to sub tropical pliocene cluster and a warm and relatively dry late miocene to early pliocene cluster however no further stages sub stages or clear climatic phases can be consistently recognized in these data a detailed lithostratigraphic framework of the study area allows a correlation of the sections independent of the pollen data results confirm the numerical analyses and furthermore point to a strong lithological depositional bias on the pollen assemblages variations in the abundance of sequoia and taxodium originally used to define the brunssumian reuverian transition and brunssumian a c sub stages are shown to represent mostly local changes the number and absolute percentage of the fluctuations in sequoia and taxodium abundances depend largely on the sample resolution and the site location within the rvg our data assessment indicates that long distance chronostratigraphic correlations based on the original continental neogene stages likely are invalid furthermore the palaeoclimatic reconstructions that have been based on the rvg successions are largely over interpreted the present palaeoclimate reconstructions from the rvg reflect variations in the highly dynamic fluvial depositional setting taphonomic effects and environmental conditions including climate a sequence stratigraphic approach combined with the analysis of interfingering marine sediments is potentially better suited to establish absolute ages and associated climatic conditions of the neogene deposits within the rvg 2007 elsevier b v all rights reserved

pliocene pleistocene vegetational and climatic evolution of the south central mediterranean abstract the vegetational history of the south central mediterranean clearly reflects the major global climatic changes of the last four million years a mediterranean type climate characterized by strong seasonality and a dry summer may have existed in this region during the early pliocene a short term climatic cooling at approximately 3 2 ma resulted in the temporary establishment of a humidity demanding flora the onset of major northern hemisphere glaciation at approximately 2 4 ma initiated an alternation between humid glacial and dry interglacial conditions vegetational differences between this region and the north west mediterranean indicate that distinct latitudinal climatic gradients probably existed in the mediterranean during the pliocene early pleistocene

pollen ostracod and stable isotope records of palaeoenvironment and climate upper miocene and pliocene of the cankiri basin central anatolia turkey abstract an integrated stratigraphic study of neogene lacustrine succession in the cankiri basin central anatolia combining pollen analysis biostratigraphy and isotope analysis records variations in vegetation and depositional environment the palynological analysis of the upper miocene interval of the studied section reveals the existence of a coniferous forest this flora reflects warm temperate humid climatic conditions the pollen changes observed at the onset of the pliocene are related to climatic changes in the early pliocene the vegetation changed to a mixed coniferous forest dominated by meso microthermic trees cedrus and cathaya with a widespread herbaceous understory poaceae sparcely interspersed with open areas occupied by asteraceae whereas abies and deciduous trees quercus carya juglans ulmus carpinus acer etc are represented by lower percentages this flora reflects a warm temperate relatively arid climate reflecting the global warm climate of the early pliocene the fluctuations in abundance of tsuga may represent fluctuations in temperature climate analysis using the coexistence approach ca shows the presence of precipitation oscillations within the pliocene the identified ostracod assemblage indicates a dominance of fresh water conditions during the early late miocene and of brackish water conditions during the late late miocene while minor salinity oscillation is present throughout the section the 18 o sulfate and 87 sr 86 sr isotopic ratios of non marine gypsum are indistinguishable from the marine evaporites this suggests recycling of older marine evaporites which is also supported by intense replacement of ostracods by gypsum

palynological evidence for the latest oligocene early miocene paleoelevation estimate in the lunpola basin central tibet uplift of the tibetan plateau is ultimately driven by the cenozoic collision between the indian and eurasian plates and their continued convergence one approach for studying the tibetan plateau uplift is to verify the paleoelevation changes from collision to present day this is important for understanding both the tectonics and the climatic effects the new high resolution palynological record of the uppermost oligocene to the lowest miocene strata from the lunpola basin indicates that the vegetation types during the latest oligocene earliest miocene were dominated by mixed coniferous broadleaved forests being different from the modern steppe vegetation by using the coexistence approach to the fossil pollen records after calibration the effects of temperature difference and the lapse rate a maximum paleoelevation of 3190 100 m asl was estimated in the lunpola basin in the latest oligocene earliest miocene being 1500 to 2000 m lower compared with the previous oxygen isotope paleoelevation in the same region

earthquake magnitude frequency epicentral distance and soft sediment deformation in sedimentary basins abstract empirical equations available for earthquake magnitude frequency and the maximum epicentral distance of liquefied sites versus magnitude are combined with the characteristic instantaneous sediment deposition rate at a station in a sedimentary basin to form a model for the local stratigraphic frequency of earthquake induced soft sediment deformation structures both the style of sedimentation and the characteristics of the earthquake source combine to determine the pattern of incidence of the structures in a basin the model is probably most directly applicable to the geodynamic interpretation of fluvial basins in which substantial volumes of readily liquefied sands accumulate at high local short term rates

soft sediment deformation structures induced by cyclic stress of storm waves in tempestites miocene guadalquivir basin spain the identification of triggering agents for soft sedimentation structures is an enigmatic geological problem mainly seismic induced soft sediment structures have been recognized in ancient sediments rather than those resulting from storm waves we analyse soft sediment deformation structures in upper miocene calcarenitic tempestites of the guadalquivir basin southern spain the most common structures are load casts which vary in height and width from 10 centimetres to several metres the structures are always restricted to a small part of the stratigraphic sections in exclusive association with tempestites the analysed soft deformation structures are interpreted to be the result of liquidization processes chiefly from their inferred depositional environment and subordinately from the deformation style we have devised basic criteria to identify the trigger mechanism in these soft sediment deformation structures the liquefaction was triggered by pore pressure changes induced by cyclic and residual stress of storm waves

persistent solar influence on north atlantic climate during the holocene surface winds and surface ocean hydrography in the subpolar north atlantic appear to have been influenced by variations in solar output through the entire holocene the evidence comes from a close correlation between inferred changes in production rates of the cosmogenic nuclides carbon 14 and beryllium 10 and centennial to millennial time scale changes in proxies of drift ice measured in deep sea sediment cores a solar forcing mechanism therefore may underlie at least the holocene segment of the north atlantic9s 1500 year cycle the surface hydrographic changes may have affected production of north atlantic deep water potentially providing an additional mechanism for amplifying the solar signals and transmitting them globally

paleoenvironmental settings of the sofia lignite basin insights from coal petrography and molecular indicators abstract compositions of balsha lignite sofia coal bearing basin bulgaria and carbonaceous shales are studied by petrological and geochemical proxies the macropetrographic characteristic of profiles is relatively constant the lignite is generally composed of dull matrix coal containing significant amounts of xylite fragments the typical microscopic constituents of the lignite are the ulminite and less frequently textinite lenses scattered within attrinitic groundmass the maceral composition of the organic matter in carbonaceous shales does not differ significantly from that of the lignite samples biomarker assemblages of the extractable portions are determined by gas chromatography mass spectrometry additional information for the compositions of residues after extractions is obtained by tmah thermally assisted hydrolysis methylation petrographic contents lipid assemblage and tmah thermally assisted hydrolysis methylation data imply that the original peat bog is formed in fresh water forest swamp preferably composed by gymnosperms polar diterpenoids argue for cupressaceae s l taxodiaceae as the most probable vegetation for one of the profiles appreciable angiosperm rich herbaceous type flora contribution is assumed polar oleanane triterepenoids and their aromatized derivatives argue for angiosperm input the relevance of a norfriedel 8 en 10 one friedelin ratio for groundwater level appraisal is discussed it admits long period of high water level in the paleomire high content of vanillyl structures and subordinated presence of syringyl units in products of tmah thermally assisted hydrolysis methylation are hint for gymnospermae input in the paleoswamp and angiospermae contribution to one of the profiles cinnamyl phenolic units indicating non woody angiosperm vegetation presence are registered as well flavonoids in products are considered as taxonomic markers of cupressaceae plants in the paleoswamp

petrographical and organic geochemical study of the kovin lignite deposit serbia abstract the origin of the organic matter om and the characteristics of the depositional environment of lignites from the upper miocene kovin deposit hosting three coal seams of serbia were evaluated based on petrographic data bulk organic geochemical parameters biomarker analysis and stable isotope geochemistry 13c of individual biomarkers samples were collected from four boreholes gd 601 and gd 603 the a field and kb 79 and kb 91 the b field representing different parts of coal seams i ii and iii investigated lignites are typical humic coals the om of lignites is derived from woody vegetation and herbaceous peat forming plants with prevalence of the former in most samples peat forming vegetation is characterized by abundant decay resistant gymnosperm coniferous plants followed by a low amount of angiosperms lignite forming plants mostly belonged to the gymnosperm families cupressaceae taxodiaceae phyllocladaceae and pinaceae slight input of ferns fungi and aquatic macrophyta to lignite om is also evident distributions of hopanoids and isotopic compositions of these biomarkers reflect the activity of various microbial populations represented by methanotrophic chemoautotrophic and heterotrophic bacteria during diagenesis prominent c28 28 30 bisnorneohop 13 18 ene was observed for the first time in the lignite extracts according to the 13c value it was probably derived from chemoautotrophic bacteria c28 28 30 bisnorneohop 13 18 ene could be one of the possible precursors of a series of orphan aromatic hopanoids bearing an ethyl group at c 21 via progressive aromatization peatification proceeded in a fresh water environment under variable redox conditions from anoxic to slightly oxic all three coal seams are heterogeneous the lower parts of the coal seams represent a topogenous fresh water peat mire with open water areas which was subjected to inundations the upper parts of coal seams represent a wet forest swamp with relatively stable conditions despite the observed variations in all three coal seams the mean values of petrographic and organic geochemical parameters suggest general increasing of wetness and establishment of more stable conditions from seam iii to seam i maceral and biomarker data indicate that rapid flooding of the bogs stopped peat growth in all three coal seams relatively frequent variations in all three coal seams followed by repetition of lignite characteristics depict well the pronounced seasonality e g short term cycles of the climate during late miocene in investigated area

palynostratigraphy and vegetation characteristics of neogene continental deposits interbedded with the cappadocia ignimbrites central anatolia turkey a palynological analysis of the late miocene and early pliocene successions of the cappadocian volcanic province central anatolia turkey has been carried out with the aim of reconstructing the palaeovegetation and palaeoclimatic conditions the samples are collected from outcrop sections from three different localities a akdag b bayramhacili and g guzeloz the pollen spectra reveals the existence of a steppe vegetation dominated by amaranthaceae chenopodiaceae and artemisia typical of present day arid and semi arid continental areas i e middle east and asteraceae asteroideae in the a section late miocene developed in arid climatic conditions the flora of the g early pliocene and lower part of the b late miocene sections reflects steppes on which asteraceae asteroideae was dominant this flora also indicates arid conditions the development of trees in the upper part of the b section was possibly related to local paleoenvironmental conditions rather than a climatic change this study provides the first palynological data to reveal the presence of an amaranthaceae chenopodiaceae and artemisia steppe already during the late miocene in turkey

simulating late pliocene northern hemisphere climate with the lln 2 d model deep sea sediment records suggest northern hemisphere glaciation intensified at approximately 2 75 ma in this paper we simulate the fluctuations of the late pliocene northern hemisphere ice sheets volume using the lln 2 d model forced by the astronomically derived insolation and by scenarios of co2 concentrations the model simulates the waxing and waning of the northern hemisphere ice volume in an acceptable agreement with geological reconstructions and in particular supports the geological evidence that the development of significant northern hemisphere ice sheets started between 2 75 and 2 55 ma a time interval accompanied by quite high and stable eccentricity values and increased obliquity amplitude when the co2 concentration is lower than a threshold value the milankovitch forcing explains the suddenness and specific timing of this entrance into the ice age during the late pliocene

multiple rifting pulses and sedimentation pattern in the cameli basin southwestern anatolia turkey abstract the neotectonic development of western anatolia was characterized by the formation of numerous graben type basins which have been well documented by general mapping although the cause and timing of the neogene regional tectonic extension remain controversial previous interpretations of the origin and evolution of these neogene basins were based mainly on regional scale tectonic inferences rather than detailed basin fill analysis the present study of the terrestrial intramontane cameli basin in the western taurides combines detailed facies analysis with biostratigraphic dating mammalian and molluscan fossils and documents three pulses of crustal extension that are reflected in changes in the palaeogeography and sedimentary architecture of the basin development of the cameli graben commenced in the vallesian time early tortonian and is marked by alluvial fan fluvial and lacustrine depositional systems with freshwater molluscan fauna a second pulse of tectonic extension occurred in the late ruscinian time early middle pliocene producing a new normal fault that split the basin longitudinally into two compartments the lake environment expanded and deepened coastal peat forming mires developed and abundant mammal fauna appeared by the early villanian time middle pliocene with the lacustrine deposits onlapping the basin margin and intrabasinal fault escarpments the lacustrine environment subsequently shrank as the progradation of axial river deltas and basin margin fan deltas caused water shallowing and shoreline regression a third pulse of extension occurred at the end of villanian time late pliocene when the development of a new generation of normal faults further split the basin into still narrower half graben compartments the third pulse of rifting is estimated to have accounted for little more than 10 of the sub basinal crustal extension but caused the most striking changes in the basin palaeogeography and drainage pattern the inward development of the successive normal faults indicated a high rate crustal extension this is the first regional case study of a terrestrial neotectonic graben employing detailed sedimentary facies analysis and mammal biostratigraphy and providing a time stratigraphic framework for the rifting pulses in western anatolia

millennial scale climatic cycles in the early pliocene pollen record of ptolemais northern greece early pliocene lacustrine sediments from the ptolemais basin northern greece exhibit a climatically induced cyclicity which can be correlated with the orbital cycle of precession superimposed on precession controlled cycles palynological time series data reveal a higher order climatic cyclicity with periodicities of 10 2 5 and 1 5 ka these millennial scale vegetation changes are likely to reflect changes of the soil moisture gradient on mountain slopes caused by fluctuations in orographic winter precipitation such fluctuations corroborate the concept of a nao like north atlantic climatic teleconnection during early pliocene times the periodicities are similar to those of climate oscillations inferred from quaternary records the occurrence of millennial scale cyclicity in a time interval when the northern hemisphere was essentially ice free implies an ultimate forcing mechanism that operated independently of changes in the thermohaline circulation in the atlantic ocean the cycles are likely to be related to long period variations in solar activity

the coexistence approach a method for quantitative reconstructions of tertiary terrestrial palaeoclimate data using plant fossils abstract the coexistence approach is introduced as a method for quantitative terrestrial palaeoclimate reconstructions in the tertiary it is based on the assumption that tertiary plant taxa have similar climatic requirements to their nearest living relatives the aim of the coexistence approach is to find for a given fossil flora and a given climate parameter the climatic interval in which all nearest living relatives of the fossil flora can coexist for this purpose we have developed a data base climbot containing for over 800 tertiary plant taxa the nearest living relatives and their climatic requirements and an algorithm for analysis climst for all types of fossil floras the coexistence approach thus allows the rapid quantitative reconstruction of 10 different climate parameters including the mean annual temperature temperature of the warmest month temperature of the coldest month mean annual precipitation maximum monthly precipitation minimum monthly precipitation precipitation of the warmest month relative humidity potential evaporation as well as the ratio of mean annual precipitation over potential evaporation the reliability and resolution of the coexistence approach are tested with various techniques and proved to be reasonably good for instance the resolution with respect to the mean annual temperature can be up to 1 c applications to various modern and fossil floras are illustrated and the advantages and disadvantages of the coexistence approach are discussed

geochemical appraisal of palaeovegetation and climate oscillation in the late miocene of western bulgaria abstract palaeobotanical methods and geochemical techniques were used to assess plant contribution and palaeoenvironment for the staniantsi basin bulgaria the aim was to connect palaeovegetation change and climate oscillation based on pollen and statistical analysis with organic geochemical proxies for a late miocene lacustrine to paludial sedimentary succession three samples from lignite marl cycles were studied the biomarker assemblage and bulk chemical data indicated that gymnosperms were not important in the palaeomire the presence of des a triterpenoids 17 21 seco triterpenoids hopanes a high content of a d ring monoaromatic hopane and aromatized triterpenoids suggested that photochemical and microbial processes significantly contributed to the alteration of the organic matter om a prolonged period of high water table and severe mechanical destruction promoted microbial activity prior to burial and enhanced decay a geochemical appraisal of short term climate oscillation ca 21 7 kyr was attempted within the limitations of the small number of samples studied the cycles are expressed as lignite marl clay layers combined with cyclic changes in swamp vegetation related to cyclic changes in groundwater level and inundation of the basin in periods of low water level swamp phase lignite accumulation took place preliminary results for selected samples suggest that the oscillation may be reflected in the content of friedelin vs possible degradation products the ratio of a chromatographic peak tentatively assigned as a norfriedel 8 en 10 one to friedelin is proposed as a means of detecting short term environmental cycles where values 1 reflect periods of inundation however time series analysis using densely sampled lignite clay layer oscillations are needed to confirm the value of this biomarker ratio for environmental reconstruction

towards an astrochronological framework for the eastern paratethys mio pliocene sedimentary sequences of the focsani basin romania abstract a reliable geological timescale for the neogene sedimentary deposits of the romanian carpathian foredeep did not exist so far due to the lack of accurate isotopic datings and straightforward magnetostratigraphic correlations here we present a new chronology for the upper miocene to pliocene deposits of the westernmost part of the eastern paratethys based on high resolution magnetostratigraphic data from the focsani basin the thick and continuous river sections of putna 2 35 km and rimnicu s rat 7 32 km yield excellent magnetostratigraphic results and allow an unambiguous correlation to the polarity timescale for the interval between 7 and 2 5 ma the new age control permits the calculation of accumulation rates for each polarity zone which shows a significant increase at approximately 5 8 6 my the upper miocene to pliocene sedimentary rocks of the focsani basin display cyclic alternations of sandy units and finer intervals the calculated values for the average duration of the observed sedimentary cycles are very close to the average duration of precession 21 7 ky which indicates that the sedimentary cycles from the eastern carpathian foredeep deposits are astronomically forced we show that the usage of the unambiguous time control offered by magnetic polarity stratigraphy would give a more realistic picture of the processes that have taken place in this tectonically active region

vegetation and climate changes during the late pliocene and early pleistocene in sw anatolia turkey abstract pollen analysis was done on lacustrine sedimentary sequences dated by micromammals as late pliocene early pleistocene that outcrop in two neogene graben basins from sw turkey this study shows vegetation changes from steppe like to more forested environments very similar to the cyclic oscillations related to late pleistocene glacial interglacial climate changes artemisia was abundant during cold arid periods indicating that this species was already widespread in this area during the latest pliocene and the beginning of the pleistocene a review of pollen records from anatolia agrees with this study suggesting that the spreading of this arid species occurred during a major climatic change the beginning of the first glaciations and probably a change in seasonality towards summer aridity artemisia temporarily disappeared from the region during warm wet periods and thus we suggest that glacial interglacial type oscillations already occurred in the area during the late pliocene early pleistocene

high resolution palynological analysis in late early middle miocene core from the pannonian basin hungary climatic changes astronomical forcing and eustatic fluctuations in the central paratethys high resolution palynological analysis in the karpatian sarmatian late early middle miocene interval of the borehole tengelic 2 hungary reveals the existence of a forest organized in altitudinal belts developed in a subtropical warm temperate humid climate reflecting the so called miocene climatic optimum pollen changes from the late early miocene to the middle miocene are related to climatic variations values of mean annual temperature ta between 18 and 20 8c and mean annual precipitation pa between 1200 and 1400 mm have been estimated bclimatic amplitude methodq for the badenian decreasing during late badenian and sarmatian ta and pa about 16 8c and 1100 mm have been interpreted as a climatic cooling correlated with the bmonterey cooling eventq and related to the development of the east antarctic ice sheet eais alternation in pollen taxa thermophilous vs altitudinal elements reflects the astronomical forcing on temperature and precipitation and then on vegetation where obliquity and eccentricity cycles dominated eustatic changes determine pinus and pinaceae and dinocyst variations

pliocene burdur basin sw turkey tectonics seismicity and sedimentation the pliocene burdur formation of sw turkey was deposited in a ne sw trending half graben with a major basement fault along its se margin hangingwall sourced fans were confined proximally by basement topography distally they developed 9ideal9 fan geometries these fans became submerged by the lake that occupied the centre of the basin this transgression was caused by the migration with time of the hangingwall pivot away from the basin controlling fault footwall sourced fans exhibit three distinctly different geometries at the northern end of the basin a wide braidplain developed due to the rapid erosion of both penecontemporaneous volcaniclastic deposits to the east and the footwall crest of a newly formed fault within the basin along the footwall scarp in the central part of the basin a narrow bajada formed in the south a large alluvial fan had its source in the relay structure between two left stepping en echelon fault segments the small size of footwall sourced fans compared with those sourced on the hangingwall slope was due to rapid subsidence of the basin floor adjacent to the footwall scarp although this suggests high levels of seismicity the general paucity of wet sediment deformation within the burdur formation indicates that seismicity in the burdur region during the pliocene was more subdued than at present

palynological evidence for miocene climate change in the forecarpathian basin central paratethys nw bulgaria abstract we reconstruct quantitatively the middle to upper miocene climate evolution in the southern forecarpathian basin central paratethys area northwest bulgaria by applying the coexistence approach to 101 well dated palynofloras isolated from three cores the climatic evolution is compared with changes in vegetation and palaeogeography the middle miocene was a period of a subtropical warm temperate humid climate with mean annual temperature mat between 16 and 18 c and mean annual precipitation map between 1100 and 1300 mm thereby during the entire middle miocene a trend of slightly decreasing temperatures is observed and only small climate fluctuations occur which are presumably related to palaeogeographic reorganisations the vegetation shows a corresponding trend with a decrease in abundance of palaeotropic and thermophilous elements the upper miocene is characterised by more diverse climatic conditions probably depending on palaeogeographic and global climatic transformations the beginning of this period is marked by a slight cooling and a significant drying of the climate with mat 13 3 17 c and map 652 759 mm after that fluctuations of all palaeoclimate parameters occur displaying cycles of humid dryer and warmer cooler conditions which are again well reflected in the vegetation our study provides a first quantitative model of the middle upper miocene palaeoclimate evolution in southeastern europe and is characterised by a relatively high precision and resolution with respect to the climate data and stratigraphy

earthquake induced structures in young sediments abstract soft sediment deformational structures have been identified in several plio quaternary horizons near burdur in southwest turkey these horizons satisfy criteria for correlating such structures with seismic events and it is proposed that the structures were formed by earthquake induced liquefaction the deformational structures are thus interpreted to represent seismic events which occurred up to 2 3 ma ago

the identification of an active fault by a multidisciplinary study at the archaeological site of sagalassos sw turkey abstract the archaeological site of sagalassos sw turkey is located in a region characterized by the absence of any significant recent seismic activity contrary to adjacent regions however the assessment of earthquake related damage at the site suggests that the earthquakes that have been demonstrated to have struck this pisidian city in ca ad 500 and in the middle or second half of the 7th century ad are characterized by an msk intensity of at least viii and occurred on a fault very close to the city different investigation techniques archaeoseismology remote sensing and geomorphology surface geology and structural data 2d resistivity imaging and palaeoseismological trenching have been applied at the archaeological site and its direct surroundings in search for the causative fault of these earthquakes this multidisciplinary approach shows that each of the different approaches independently provides only partial non conclusive information with respect to the fault identification integration is imperative to give a conclusive answer in the search for the causative fault this study has indeed revealed the existence of a to date unknown active normal fault system passing underneath ancient sagalassos i e the sagalassos fault a historical coseismic surface rupture event on this fault could be identified this event possibly corresponds to the devastating sagalassos earthquakes of ca ad 500 and the middle or second half of the 7th century ad finally this study demonstrates that in the particular geodynamic setting of sw turkey archaeological sites with extensive earthquake related damage form an important tool in any attempt to asses the seismic hazard

orbital forcing in pliocene pleistocene mediterranean lacustrine deposits dominant expression of eccentricity versus precession abstract milankovitch forcing of climate is expressed in the sedimentary record as lithological cycles that can have one or more of four typical periods related to precession 21 kyr obliquity 41 kyr and eccentricity 100 and 400 kyr in several mediterranean continental successions striking differences in the expression of particularly precession and eccentricity appear we present the results of an additional lower pliocene lacustrine succession from lupoaia southern romania and compare the cyclic expression in this lignite siliciclastic basin in detail with the time equivalent lignite carbonate basin of ptolemais northern greece the middle pleistocene lignite siliciclastic basin of megalopolis southern greece and the miocene carbonate clay basin of orera north eastern spain it appears that carbonate basins dominantly express precession while siliciclastic basins dominantly express eccentricity in their lithological cycles this can be explained by a more linear response to insolation forcing in carbonate basins than in siliciclastic basins alternatively it can be explained by the low amplitude of 100 kyr eccentricity at the times the carbonate sections were deposited this reduced 100 kyr amplitude was caused by minima in the 2 35 myr eccentricity cycle that co occurred with the deposition in both carbonate basins finally the expression of 100 kyr eccentricity appears to be independent of glacial cyclicity

astronomical forcing in upper miocene continental sequences implications for the geomagnetic polarity time scale abstract we present an integrated stratigraphic study of cyclically bedded distal alluvial fan to lacustrine deposits in the late miocene continental sections of cascante and canizar teruel basin ne spain the cyclostratigraphic analysis reveals that different scales of sedimentary cyclicity are present with a thickness ratio of about 1 2 5 spectral analysis of colour records in the depth domain indicates the presence of a significant peak at 2 2 m which corresponds to the average thickness of the basic mudstone carbonate cycle other peaks correspond to the large scale cycle which consists of clusters of five basic cycles and to a cycle twice the average thickness of the basic cycle magnetostratigraphic results in combination with small mammal biostratigraphy indicate that the three normal polarity intervals recorded in our sections correspond to c5n 2n c5n 1n and c4ar 2n assigning the ages of ck95 to the polarity reversals implies significant changes in sedimentation rate which is not in agreement with the regularity of the sedimentary cyclicity thus spectral analysis of high resolution colour records in the time domain only produce a spectrum that is consistent with milankovitch climate forcing if several of the assigned age tie points are excluded this indicates that the sedimentary cyclicity in these sections is related to astronomical variations in climate and that the ages of reversal boundaries are in error hence we have calculated the astronomical durations for c4ar 2n 87 ky c4ar 3r 54 ky c5n 1n 141 ky and c5n 1r 33 ky which indeed show significant discrepancies with ck95 the duration pattern of our polarity intervals is confirmed by seafloor anomaly profiles and magnetostratigraphic records of deep sea cores consequently this study demonstrates that astronomically forcing in continental sequences can be a powerful tool to improve the fundamental dating of the geological record

millennial scale vegetation dynamics in an estuary at the onset of the miocene climate optimum article i nfo pollen analyses have been proven to possess the possibility to decipher rapid vegetational and climate shifts in neogene sedimentary records herein a c 21 kyr long transgression regression cycle from the lower austrian locality stetten is analysed in detail to evaluate climatic benchmarks for the early phase of the middle miocene climate optimum and to estimate the pace of environmental change based on the coexistence approach a very clear signal of seasonality can be reconstructed a warm and wet summer season with c 204 236 mm precipitation during the wettest month was opposed by a rather dry winter season with precipitation of c 9 24 mm during the driest month the mean annual temperature ranged between 15 7 and 20 8 c with about 9 6 13 3 c during the cold season and 24 7 27 9 c during the warmest month in contrast today s climate of this area with an annual temperature of 9 8 c and 660 mm rainfall is characterized by the winter season mean temperature 1 4 c mean precipitation 39 mm and a summer mean temperature of 19 9 c mean precipitation 84 mm different modes of environmental shifts shaped the composition of the vegetation within few millennia marshes and salt marshes with abundant cyperaceae rapidly graded into taxodiaceae swamps this quick but gradual process was interrupted by swift marine ingressions which took place on a decadal to centennial scale the transgression is accompanied by blooms of dinoflagellates and of the green alga prasinophyta and an increase in abies and picea afterwards the retreat of the sea and the progradation of estuarine and wetland settings were a gradual progress again despite a clear sedimentological cyclicity which is related to the 21 kyr precessional forcing the climate data show little variation this missing pattern might be due to the buffering of the precessional related climate signal by the subtropical vegetation another explanation could be the method inherent broad range of climate parameter estimates that could cover small scale climatic changes

pollen record and integrated high resolution chronology of the early pliocene dacic basin southwestern romania an integrated stratigraphic study has been performed on four early pliocene fssections in the western dacic basin including the long reference section of lupoaia based on the integration of mediterranean nannoplankton assemblages the regional lignite stratigraphy records of large and small mammals large climatic fluctuations according to pollen grains and climatostratigraphic relationships at the european scale it has been possible to establish a magnetostratigraphic correlation of the different sections to the geomagnetic polarity time scale gpts this correlation suggests that all normal episodes of the early pliocene from thvera to cochiti chrons are recorded hence the complete pollen record covers an almost continuous time span from about 5 33 to 4 30 ma in addition the regional dacian romanian stage boundary in the dacic basin is located in the nunivak c3n 3n episode with an age of 4 55 0 05 ma our chronologic calibration combined with high resolution pollen data results in a detailed record of paleoclimate in which the 100 kyrs and 400 kyrs eccentricity cycles are clearly identified

controls of sedimentation in the malawi rift valley central africa abstract the malawi rift is the southermost classic rift valley trough in the cenozoic african rift valley system much of its floor is flooded by lake malawi which is approximately 570 km long 60 km across and up to 500 m deep this rift basin is a potentially useful analogue of many economically important ancient sedimentary troughs rift valley structures are extremely important in controlling both the distribution of sediments in the basin as a whole and also details of sedimentation on a local scale on the basin wide scale an important association between the type of rift boundary structure and amount of rift floor subsidence is recognised this association appears to apply to several section of the african rift system pre rift topography is major control on the position of major rivers and their deltas or turbidite fans along the basin margin the area of pre rift drainage network captured in the course of rift movements is a significant factor in the hydrologic budget of the basin climate is however the dominant control on the hydrologic budget and at present the basin is flooded to overflow level prevailing winds are important in beach ridge and back beach aeolian dune development climatic conditions produce thermal stratification of the lake with an oxic epilimnion down to 250 m depth overlying an anoxic hypolimnion the oxic bottom waters in the shallower parts of the lake appear to promote iron precipitation in the sediments

astronomic timescale for the pliocene atlantic δ18o and dust flux records of ocean drilling program site 659 high resolution benthic oxygen isotope and dust flux records from ocean drilling program site 659 have been analyzed to extend the astronomically calibrated isotope timescale for the atlantic from 2 85 ma back to 5 ma spectral analysis of the 18o record indicates that the 41 kyr period of earth s orbital obliquity dominates the pliocene record this is shown to be true regardless of fundamental changes in the earth s climate during the pliocene however the cycles of sahelian aridity fluctuations indicate a shift in spectral character near 3 ma from the early pliocene to 3 ma the periodicities were dominantly precessional 19 and 23 kyr and remained strong until 1 5 ma subsequent to 3 ma the variance at the obliquity period 41 kyr increased the timescale tuned to precession suggests that the pliocene was longer than previously estimated by more than 0 5 m y

from palaeotectonics to neotectonics in the neotethys realm the importance of kinematic decoupling and inherited structural grain in sw anatolia turkey abstract in order to asses young i e neotectonic fault kinematics and the relation with plate tectonic processes in sw turkey we focused on the questions 1 what produced the structural grain i e how and when are faults generated 2 what was is the kinematic behaviour of these faults and 3 during which period s were these faults active firstly the distribution of faults has been investigated using a lineament analysis performed on satellite imagery and digital elevation models we define five main tectonic domains in sw turkey 1 and 2 the northern and southern western anatolian extensional provinces 3 the eastern hellenic arc including rhodes island and the submarine anaximander mountains 4 the lycian taurides and 5 the western limb of the isparta angle lineament analysis reveals dominance of three lineament groups i e nne ene and wnw trending in all identified domains variations in the relative importance of lineament groups exist and are attributed to the specific tectonic evolution of each domain a synthesis of recently published field data shows that the onset of activity of related fault groups is neither synchronous nor uniform the structural grain for the neotectonic deformation in sw turkey is formed during the last stage of palaeotectonic deformation stage 1 which is dominated by the onset of the menderes massif exhumation along a top n major detachment the datca break away fault seyitoglu g isik v and cemen i 2004 complete tertiary exhumation history of the menderes massif western turkey an alternative working hypothesis terra nova 16 358 364 and related se ward sliding of the lycian nappes in the footwall of this fault this stage is characterized by spatially variable types of deformation that are delineated by from nw to se the datca fault around the menderes lycian contact zone and the lycian frontal thrust zone respectively the kinematic decoupling along these structures explains the co existence of top n detachment type extension in the western anatolian extensional province and ongoing nappe emplacement and piggy back development in the lycian taurides the decoupling also explains the lateral complexity of deformation associated with later neotectonic deformation from late miocene onward stage 2 nne ssw extension dominated the western anatolian extensional province influenced by combined anatolian extrusion and hellenic subduction roll back contemporaneously bidirectional ese wnw and nne ssw extension controls the lycian taurides due to the effects of hellenic arc expansion superposed on extrusion roll back extension the zone of kinematic decoupling is characterized by structural complexity with local transpressional features during stage 3 post late pliocene the same types of extension prevail in the western anatolian extensional province and the lycian taurides although a third tectonic regime becomes gradually more important this regime is associated with a tectonic escape in the hellenic arc that induced forearc slivers to be sheared of the expanding arc along mostly sinistrally displacing ene trending strike slip zones several of these zones have been identified in the coastal zones of sw turkey either through recent seismicity or field observations and are especially focused in the lycian taurides domain here they form what is classically referred to as the fethiye burdur fault zone which becomes gradually penetrated from the sw by oblique or strike slip zones exemplifying the time transgressive nature of the tectonic escape mechanism zones of kinematic decoupling remain persistent throughout the entire early miocene recent tectonic evolution of sw turkey and explain the existence of differently deforming tectonic domains

a late eocene palynological record of climate change and tibetan plateau uplift xining basin china climate models suggest that asian paleoenvironments monsoons and continental aridification were primarily governed by tectonic uplift and sea retreat since the eocene with potential contribution of global climate changes however the cause and timing of these paleoenvironmental changes remain poorly constrained the recently well dated continental mudflat to ephemeral saline lake sedimentary succession situated in the xining basin at the northeastern margin of the tibetan plateau nw china provides a unique opportunity to develop additional proxy successions in this area that are placed accurately in time here a palynological record from this succession is reported high abundances of desert and steppe desert taxa such as ephedripites and nitrariadites nitraripollis are found which can be differentiated by the presence of broad leaved deciduous forest taxa in the lower part of the section particularly up to 36 4 ma magnetochron c16r and a sudden increase of pinaceae pinuspollenites piceaepollenites and abiespollenites which is dated at 36 1 ma c16n 2n coexistence approach coa indicates that from 39 9 to 36 4 ma c17n 1n regional climate was warm and wet while from 36 4 to 33 5 ma c16n 2n c13r climate tends to be cooler and drier the data indicate that paleoenvironmental and palynological changes on the ne part of the tibetan plateau resulted from a combination of long term tectonic uplift forcing and long and short term climate changes the increase of taxa such as piceaepollenites and abiespollenites indicates not only a cooling and drying trend prior to the eocene oligocene e o boundary but also the existence of high altitude mountain habitats in the periphery of the xining basin the sudden pinaceae event correlates closely in time with a marked aridification step as viewed from the lithology of the xining basin that was linked to the sea retreat out of the tarim basin

timing of arrival of the danube to the black sea provenance of sediments from dsdp site 380 380a estimates for the timing of the arrival of danube sediment to the black sea range from messinian to pleistocene the river is currently the largest sediment contributor supplying 88 mt yr we identify two changes in siltstone provenance sensitive heavy mineral abundances at dsdp site 380 380a in the southwest black sea comparison with modern river sediment compositions indicates that siltstones above 571 5 mbsf metres below sea floor were supplied by the danube while sediments below 651 0 m were sourced by other supply systems palaeo magnetic 40ar 39ar and biostratigraphic data reveal that the influx of danube supplied sediment to the southwest black sea began between 4 36 0 19 ma and 1 ma ago zanclean calabrian our results provide an independent time constraint on palaeogeographic reconstructions of the pannonian and dacian basins which acted as upstream sediment sinks and suggest that significant volumes of danube supplied sediment only started to reach the black sea at least 1 ma after the messinian salinity crisis 5 971 5 33 ma had ended

biotic and abiotic response to palaeoenvironmental changes at lake pannons western margin central europe late miocene a multidisciplinary study was performed on a c 30 m thick limnic deltaic sequence in the styrian basin austria geophysical gamma ray activity rock magnetism geochemical organic carbon sulphur and sedimentological observations were combined with palaeontological information mainly ostracods on this base several ecological factors were deduced terrigenous influx salinity water depth and oxygenation based on integrated stratigraphy as well as on palaeomagnetic results the whole section is set to chron c5r 2r 1n 11 308 11 263 ma and covers a period of less than 45 kyr in addition to the long term record we analysed short term changes by high resolution sampling 5 mm sample interval ostracods magnetic susceptibility this 2 3 m thick interval spans in total 3500 yr with an individual sample resolution of a few years only the combination of these data permit the description of the palaeoenvironmental evolution of the section in detail at the base of the section the development of a conifer swamp on the lakeside of lake pannon is documented this almost freshwater swamp existed for some centuries before it became extinct within a few decades due to a rise of the water table the drowning is related to a transgression of lake pannon which triggered the establishment of a brackish water fauna as well as greigite formation in the lake sediments in general the ongoing transgression favoured benthic life due to increased salinity up to mesohaline conditions the high resolution ostracod and magnetic susceptibility record reflect short term fluctuations in bottom water ventilation these oscillations probably range in the order of centuries and decades and are possibly related to climatic shifts later the successive deepening of the lake resulted in a significant faunal turnover a meromictic system with a well established oxygen depleted hypolimnion developed finally the limnic phase was replaced by a prograding deltaic system where the amplified input of coarse grained material and freshwater also affected benthic life periodic changes in clay illite content were detected by the gamma ray log throughout the entire section the observed cycles 5 12 kyr of the gamma ray log may reflect a super ordinate modulation of the sedimentary record by climatically forced changes in precipitation or run off

refinement of the messinian apts from sedimentary cycle patterns in the lacustrine lava section servia basin nw greece a high resolution cyclostratigraphy and magnetostratigraphy is presented for the messinian lacustrine lava section from the servia basin in nw greece constraining more precisely the absolute ages of magnetic polarity subchrons c3an 1n and c3an 2n the section contains 15 distinct sedimentary cycles of alternating dark and light coloured marls while the gamma ray attenuation record reveals an additional five to six cycles the cycles in the lower half of the section are on average 5 3 m thick as opposed to the cycles in the upper part which have an average thickness of 3 1 m palynological results define the lithological alternations in both the lower and upper cycles in terms of periodic changes in humidity where the light marls represent the humid periods and the dark marls the relatively dry periods changes in cycle thickness and shifts in average gamma ray values suggest a rather abrupt decrease in sedimentation rate at v60 m in the section this is confirmed by the magnetostratigraphy which recorded four reversals which given the biostratigraphic constraints from the lava locality could be correlated unambiguously to subchrons c3an 1n and c3an 2n of the geomagnetic polarity time scale with this magnetostratigraphic time control the average duration of the cycles can be calculated to be constant in the entire section and similar to precession the astronomical origin of the cycles is confirmed by the results of spectral analyses of gamma ray and susceptibility time series the sedimentary cycles in the upper part of the lava section are unambiguously tuned to insolation using the typical clustering of the cycles that follows the eccentricity cycle the filtered gamma ray record centred at 41 kyr confirms the tuning in the upper part and allows tuning of the lower part the tuning results in accurate ages for the sedimentary cycles and polarity reversals that confirm the astronomical tuning of krijgsman et al nature 400 1999 652 655 but define more precisely the astronomical polarity time scale fl 2000 elsevier science b v all rights reserved

long period cyclic sedimentation with constant tectonic forcing in an experimental relay ramp it is widely believed that cyclic sedimentation in active tectonic basins is caused by external forcing such as sea level cycles episodic tectonic events or variation in sediment supply due to climate change here we present a case of cyclic sedimentation in an experiment subject to constant fault slip rate and sediment discharge with no base level fluctuation the experiment was designed to study sedimentation in a simplified extensional relay ramp system reorganization of the fluvial channel network in a cyclic manner caused local variation in sediment supply to the hanging wall basin where subsidence was maximized and resulted in autogenic appearance and disappearance of a lake associated with 90 rotation of paleocurrent direction and delta formation comparing an early phase of the experiment using no external forcing i e no tectonic movement or base level change with the following main phase of the experiment i e including subsidence in an extensional relay ramp pattern shows that the characteristic time scale for channel mobility was five times longer during the phase with subsidence than during the previous phase without subsidence active fault slip imposed a new longer time scale for autogenic dynamics by establishing a linked tectonic sedimentation system scaling the experimental results to field length and time scales suggests that comparable autogenic cycles would produce 10 20 m thick strata on time scales of 105 yr comparable to observed cases attributed to allogenic effects

vegetation differences and diagenetic changes between two bulgarian lignite deposits insights from coal petrology and biomarker composition abstract during the miocene numerous sedimentary basins formed on the territory of bulgaria as a result of the extensional tectonic settings related to the post orogenic development of the late alpine orogen in this study we review the petrographic composition and biomarker assemblage of two adjacent basins in western bulgaria i e beli breg and staniantsi basins both contain lignite formed during late miocene c 6 ma despite similar tectonic settings and depositional environments the lignite seams possess different petrographic and organic geochemical characteristics reflecting differences in the peat forming palaeo communities and facies variations the peat forming vegetation in beli breg basin was dominated by decay resistant coniferous plants as indicated by abundant fossil wood remains very good tissue preservation and a biomarker assemblage dominated by diterpenoids in contrast staniantsi lignite is poor in fossil wood and contains a significant amount of triterpenoid biomarkers suggesting the predominance of angiosperm plants in the swamp the results of the biomarker analyses are consistent with palaeobotanical and palynological data from the literature the lignite seams in both basins formed under frequently changing eh conditions as indicated by the severe degradation of the non gymnosperm tissues the low gelification index values and the variations in pristane phytane ratio probably as a result of seasonal drying of the swamps and changes of the ground water table hopanoid contents in beli breg lignite are very low and are consistent with the abundance of decay resistant vegetation in contrast bacterial activity was obviously higher in the staniantsi swamp however resulting only in slightly enhanced gelification of plant tissues the geochemical data suggest that the diagenetic changes of the organic matter were mainly governed by thermal degradation rather than bacterial activity

quantitative analysis of paratethys sea level change during the messinian salinity crisis at the time of the messinian salinity crisis in the mediterranean sea i e the pontian stage of the paratethys the paratethys sea level dropped also evidence found in the sedimentary record of the black sea and the caspian sea has been interpreted to indicate that a sea level fall occurred between 5 6 and 5 5 ma estimates for the magnitude of this fall range between tens of meters to more than 1500 m the purpose of this study is to provide quantitative insight into the sensitivity of the water level of the black sea and the caspian sea to the hydrologic budget for a scenario in which the paratethys is disconnected from the mediterranean using a late miocene bathymetry based on a palaeographic map we quantify the fall in sea level the mean salinity and the time to reach equilibrium for a wide range of negative hydrologic budgets by combining our results with i estimates calculated from a set of recent global late miocene climate simulations and ii reconstructed basin salinities we are able to rule out a drop in sea level of the order of 1000 m in the caspian sea during this time period in the black sea however such a large sea level fall cannot be fully discarded

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

the coexistence approach theoretical background and practical considerations of using plant fossils for climate quantification the coexistence approach was established by mosbrugger and utescher 1997 as a plant based method to reconstruct palaeoclimate by considering recent climatic distribution ranges of the nearest living relatives of each fossil taxon during its existence for over more than 15 years its basics have been tested and reviewed in comparison with other terrestrial and marine climate reconstruction techniques and climate modelling data however some controversies remain about its underlying data or its applicability in general in view of these controversies this paper discusses the power and limitations of the coexistence approach by summarising past results and new developments we give insights into the details and problems of each step of the application from the assignment of the fossil plant to the most suitable nearest living relative the crucial consideration of the usefulness of specific taxa towards their climatic values and the correct interpretation of the software based suggested palaeoclimatic intervals furthermore we reflect on the fundamental data integrated in the coexistence approach by explaining different concepts and usages of plant distribution information and the advantages and disadvantages of modern climatic maps additionally we elaborate on the importance of continually updating the information incorporated in the database due to new findings in e g palaeo botany meteorology and computer technology finally for a transparent and appropriate use we give certain guidelines for future applications and emphasize to users how to carefully consider and discuss their results we show the coexistence approach to be an adaptive method capable of yielding palaeoclimatic and palaeoenvironmental information through rime and space c 2014 elsevier b v all rights reserved

euro north african sirenia biodiversity as a response to climate variations abstract earth has a latitudinal biodiversity gradient in which more species inhabit tropical than polar regions frequently attributed to seasonality this ecological pattern is applied to the evolution of the euro north african sirenians and its relation to cenozoic climate change climate disruption changes in seasonality and geological processes such as sea level variations are statistically tested as primary drivers to explain sirenian evolution and regional amphi mediterranean sirenian speciation and biodiversity

sedimentary cycles and volcanic ash beds in the lower pliocene lacustrine succession of ptolemais nw greece discrepancy between 40ar 39ar and astronomical ages a high resolution cyclostratigraphy for the rhythmically bedded lignite marl sequences of the lower pliocene ptolemais formation is combined with 40 ar 39 ar dating results of intercalated volcanic ash beds detailed field reconnaissance in three open pit lignite mines reveals three end member sediment types lignites composed primarily of organic material grey marls a mixture of carbonate and organic material and beige marls almost exclusively composed of carbonate these lithologies are arranged in two basic types of sedimentary cycles lignite grey marl and lignite beige marl cycles a cyclostratigraphic composite section comprising 56 lignite marl cycles is constructed which combines the consistent cycle patterns from three parallel sections the concordant positions of 20 volcanic ash beds in these sections confirm the cyclostratigraphic correlations and indicate that the lignite marl cycles result from regional basin wide forcing rather than lateral facies migrations 40 ar 39 ar ages on sanidine and biotite separates from nine volcanic ash beds were obtained by multiple total fusion and incremental heating experiments the 40 ar 39 ar ages range between 5 00 0 05 and 4 04 0 04 ma and are in general consistent with the stratigraphic order a least square linear regression using the measured 40 ar 39 ar ages gives an average duration of 21 8 0 8 kyr per lignite marl cycle evidently the lignite marl cycles in the ptolemais formation are linked to the precessional variation in the earth s orbit through its influence on mediterranean climate for the first time 40 ar 39 ar dating results totally independent from any other dating and or tuning technique confirm the astronomical theory of climate change the 40 ar 39 ar ages of the volcanic ash beds show a constant200 kyr 4 5 age discrepancy with the astronomical ages of the same ash beds this inconsistency remains difficult to explain the discrepancy is unlikely to have resulted from erroneous astronomical ages through incorrectness in the astronomical tuning inaccuracies of the magnetostratigraphic data or the orbital time series used and or errors in the apts the 40 ar 39 ar dating results neither give clear indications for a possible source of error from the excellent data set it is evident that neither loss of radiogenic 40 ar nor an underestimation of the contribution of ca and k derived ar isotopes could have caused the discrepancy moreover the discrepancy is also beyond the errors in the systematic variables like the decay constants of 40 k or the ages for the neutron fluence monitors 1999 elsevier science b v all rights reserved

undrained cyclic loading on a saturated dense sand stratum an analytical approach using finite elements is employed to study the validity of a hypothesis for explaining the presence of spiky acceleration records observed in centrifuge model earthquake tests on embankments and islands this hypothesis attributes the presence of spiky acceleration records to the recoupling of motions caused by the transient recovery of stiffness of the dense sand in a state of cyclic mobility the analyses show that spiky acceleration records similar to those observed experimentally can be generated analytically in the problem of a saturated dense sand layer if the material behaviour is of a hardening type these acceleration spikes coincide with the onset of the hardening phase thus supporting the above hypothesis the analyses also show that this type of acceleration response cannot be obtained if the material behaviour is of a softening type as the behaviour of saturated dense sand under undrained cyclic loading belongs to the hardening type the mechanism discussed in this pa

late miocene and early pliocene environments in the southwestern black sea region from high resolution palynology of dsdp site 380a leg 42b a high resolution palynological study has been performed on late miocene messinian and early pliocene zanclean sediments cored at dsdp site 380a leg 42b a late miocene coastal vegetation has been identified in association with a delta environment the pliocene is characterised by competition between the two most important vegetation components namely humid thermophilous forests and dry steppes with changes driven by large amplitude climatic variations these variations are linked to other european reference pollen records and to the global temperature evolution for the early pliocene and result in climatostratigraphic relationships at large geographic scale an orbital tuning is proposed with respect to new data clarifying time control on the section the black sea appears to have dried up in response to the messinian salinity crisis in the mediterranean with which it might have been connected during periods of high sea level

miocene climate evolution of northern europe a palynological investigation from denmark a palynological investigation has been conducted on lower upper miocene sediments from jylland denmark corresponding to the time interval of about 19 to 8 ma the sediments derived from the sdr vium drill core were deposited in marine to marginal marine environments as shown by the relatively high abundance of dinoflagellate cysts in all samples nevertheless rich and diverse pollen assemblages occur throughout the succession and the palynological analysis reveals that coastal areas of the study area were during the miocene dominated by taxodium swamp forests that also hosted terrestrial angiosperms such as nyssa betula alms and elements of the myricaceae further inland a mixed deciduous evergreen forest prevailed in areas with better drained soils or on elevated areas gymnospermous conifer forests prevailed including taxa such as pinus sequoia and sciadopitys overall the climate in the study area was warm temperate during major parts of the miocene with mean annual temperatures between 15 5 and 20 degrees c by employing the coexistence approach combined with the method of allocating taxa into standardized climatic groups four different climatic miocene events are detected within the studied succession correlated to the coeval climate record of northwestern europe the oldest event is a cooling during the earlier burdigalian at approximately 19 ma coinciding with the mbi 1 oxygen isotope excursion at ca 18 5 ma in mid burdigalian a warming phase is reconstructed characterized by the highest precipitation rates observed in the sedimentary succession a warming trend starting in the latest burdigalian corresponds to the globally recognized middle miocene climatic optimum mmco while a longer term late neogene cooling was initiated in the mid serravallian about 13 ma c 2011 elsevier b v all rights reserved less

a sediment fingerprinting approach to understand the geomorphic coupling in an eastern mediterranean mountainous river catchment article i nfo article history to understand the response of a river to anthropogenic disturbance knowledge of the links between erosion sed iment deposition and sediment export iscrucial therefore starting from field observations and connectivity prox ies a sediment fingerprinting approach using geochemical tracers was used to elucidate the subrecent sediment dynamics in the 264 km 2 bugduz river catchment in sw turkey a topography based connectivity index was used as a proxy for hillslope channel coupling and stream power estimations as a proxy for the within channel connectivity quantitative provenance information providesa link between potential sediment sources and the de rived sediment currently stored within the fluvial system provenance signals from both contemporary river bed sediments n 144 and subrecent floodplain deposits n 2 8 provide more insight into the coupling of the hillslopes to the river channel and the coupling within the river channel itself furthermore comparing the prov enance signal with the areal extent of potential sediment sources upstream in the form of enrichment ratios sheds light upon the variation of the erodibility of the sources andthe connectivity within the catchment results indicate that the valleygradient exerts an important control on the spatial variability of geomorphic coupling in the bugduz catchment furthermore different sediment sources lithologies show distinct sediment production rates in ad dition to the observed spatial variability coupling relations are characterized by an important seasonal variation indicated by variable contributions of local and more distant sediment sources

evidence from the gediz graben for episodic two stage extension in western turkey western turkey falls within a wide belt of nne ssw directed active continental extension generally similar to the basin and range province of the usa it comprises a zone of wnw ese trending major grabens detailed study of the gediz graben reveals two contrasting infills that represent two distinct extensional stages separated by a short phase of compression the older infill consists of an 800 m thick folded and exhumed continental sedimentary sequence with intercalated calc alkaline volcanics it accumulated in a basin formed in the northern hanging wall of a detachment fault during miocene early pliocene times the younger infill rests on the older infill with angular unconformity and consists of about 170 m of undeformed terraced continental sediments and basaltic lavas it accumulated during plio quaternary times in an asymmetric graben bounded by step like normal faults this later extension was probably triggered by the commencement of sea floor spreading along the red sea in early pliocene times and has persisted to the present almost all the grabens in western turkey are best explained by this episodic two stage graben model with an intervening phase of short term compression which differs from the progressive evolution inferred for the basin and range province of the usa

cenozoic continental climatic evolution of central europe continental climate evolution of central europe has been reconstructed quantitatively for the last 45 million years providing inferred data on mean annual temperature and precipitation and winter and summer temperatures although some regional effects occur the european cenozoic continental climate record correlates well with the global oxygen isotope record from marine environments during the last 45 million years continental cooling is especially pronounced for inferred winter temperatures but hardly observable from summer temperatures correspondingly cenozoic cooling in central europe is directly associated with an increase of seasonality in contrast inferred cenozoic mean annual precipitation remained relatively stable indicating the importance of latent heat transport throughout the cenozoic moreover our data support the concept that changes in atmospheric co2 concentrations although linked to climate changes were not the major driving force of cenozoic cooling

how much did climate force the messinian salinity crisis quantified climatic conditions from pollen records in the mediterranean region the latest miocene 5 96 to 5 33 ma is characterised by an outstanding event the desiccation of the mediterranean sea messinian salinity crisis it has been suggested that this was caused by a tectonic event with no climatic change playing a role in desiccation quantifying the climate of the region during this period will help support or refute this hypothesis an effective method for reconstructing the climate from neogene pollen data is the climatic amplitude method based on the modern climatic requirements of plants to interpret fossil data it has been conceived especially for periods devoid of modern vegetation analogue twenty messinian to lower zanclean pollen sequences are now available in the peri mediterranean region most of them do not cover the whole messinian interval particularly those along the mediterranean shorelines where sedimentation was interrupted during the sea s desiccation in contrast sedimentation was almost continuous in such areas as the atlantic side of morocco along the adriatic coast including the po valley and to a lesser extent the black sea the mediterranean sites nonetheless provide a reliable if not a discontinuous record of vegetation variability in time and space a first examination of the pollen diagrams reveals a high regional variability controlled by local conditions and throughout the interval a southward increase in herb pollen frequency in contrast to the tree pollen frequency this indicates that open and probably dry environments existed in the southern mediterranean region prior to during and after the salinity crisis trees developed in areas close to mountains such as in the po valley in cerdanya and in the black sea region most variations observed in the pollen diagrams are constrained by fluctuations of pinus pollen amounts indicating eustatic variations climatic quantification from pollen data does not show obvious climatic changes due to the desiccation of the mediterranean sea especially in the dry and warm southwestern mediterranean area sicily southern spain and north africa at maccarone along the adriatic sea a decrease in temperatures of the coldest month and less importantly a decrease in mean annual temperatures corresponding to a drastic vegetation change are reconstructed these temperature variations are assumed to be controlled by regional environmental changes massive arrival of waters in this basin rather than to reflect cooling because some authors link the second phase of evaporite deposition to a period of global warming some migrations of plants probably occurred as a response to mediterranean desiccation but the climatic contrast which has probably existed at that time between the central mediterranean and the peripheral areas might be amplified climatic reconstruction from pollen data in the western mediterranean area shows that climate is not the direct cause of the mediterranean desiccation as the mediterranean region had experienced continuously high evaporation long before the crisis therefore the main factor leading to this event seems to be the successive closures of the betic and rifian corridors isolating the mediterranean sea from the atlantic ocean

miocene vegetation and climate dynamics in eastern and central paratethys southeastern europe abstract from the cretaceous to modern time the earth s climate system has changed repeatedly from a greenhouse to an icehouse the miocene appeared as the last warm episode in earth history prior to the establishment of large northern hemisphere ice sheets furthermore the miocene was characterized by both large scale marine transgressions and pronounced episodes of regressions e g opening and closure of marine corridors as well as appearance and disappearance of lakes and swamps the sea level changes and instability of the climate system strongly influenced not only marine ecosystems but also the terrestrial biota to throw new light on the miocene evolution of european ecosystems and climate dynamics we compared plant assemblages from southeastern europe palaeogeographically this area is a transitional belt between tethyan and paratethyan realms and it thus constitutes a crucial geographical position when one tries to comprehend the exchange pathways of various floristic elements appearance and evolution of steppe vegetation interaction between forest and steppe vegetation and of course the corresponding climates influencing the vegetation dynamics both macro and microfloristic plant associations were considered in our analysis large palaeofloristic and palaeocoenotic transformations occurred during the miocene the early to middle miocene flora is rich and diverse in thermophilous elements which formed polydominant mesophytic to hygromesophytic forests early miocene climate was warm and humid with mean annual temperatures mainly above 16 c and annual rainfalls over 1000 mm the middle miocene was the warmest period of the whole miocene with annual temperatures ranging from 17 c to 19 c and winter temperatures from 7 c to 12 5 c climatic changes after the miocene climatic optimum caused changes in floristic composition and vegetation structure the vegetation shows a decreasing trend in abundance of palaeotropic and thermophilous elements reduction of macrothermic elements and disappearance of evergreen laurel forests together with these changes is a corresponding increase in the role of arctotertiary species in plant communities and they became dominants in mesophytic forests the available data indicate that major vegetation changes occur in the late miocene this period is characterized by more diverse climatic conditions which were directed by global climatic changes and probably complicated by regional palaeogeographic reorganizations and tectonic processes slight cooling and some drying is recorded for the beginning of the late miocene followed by fluctuations of palaeoclimate parameters observed which display cycling change of humid dryer and warmer cooler conditions our study provides a new insights on the miocene vegetation and climate dynamics and evolution in southeastern europe

quantitative reconstruction of the late miocene monsoon climates of southwest china a case study of the lincang flora from yunnan province the miocene lincang leaf assemblage is used in this paper as proxy data to reconstruct the palaeoclimate of southwestern yunnan sw china and the evolution of monsoon intensity three quantitative methods were chosen for this reconstruction i e leaf margin analysis lma climate leaf analysis multivariate program clamp and the coexistence approach ca these methods however yield inconsistent results particularly for the precipitation as also shown in european and other east asian cenozoic floras the wide range of the reconstructed climatic parameters includes the mean annual temperature mat of 18 5 24 7 degrees c and the mean annual precipitation map of 1213 3711 mm compared with the modem lincang climate mat 17 3 degrees c map 1178 7 mm the miocene climate is slightly warmer wetter and has a higher temperature seasonality a detailed comparison on the palaeoclimatic variables with the coeval late miocene xiaolongtan flora from the eastern part of yunnan allows us to investigate the development and interactions of both south asian and east asian monsoons during the late miocene in southwest china now under strong influence of these monsoon systems our results suggest that the monsoon climate has already been established in southwest yunnan during the late miocene furthermore our results support that both southeast asian and east asian monsoons co occurred in yunnan during the late miocene c 2010 elsevier b v all rights reserved

different stress states in the burdur isparta region sw turkey since late miocene times a reflection of a transient stress regime abstract the burdur isparta region is a transitional zone between two distinct neotectonic domains in turkey the burdur graben system as the northeastern part of the fethiye burdur fault zone and the kovada graben at the apex of the isparta angle each domain represents a particular stress regime fault data from unconsolidated pliocene and quaternary deposits were combined with stress states deduced from pre pliocene consolidated rocks in order to reconstruct the stress field evolution in the study area since late miocene different stress states were identified they were put in a stratigraphic framework and u th dating of fault related calcite precipitates proved to be an additional tool in constraining the history of the stress states the reconstructed history reflects a transient stress regime the evolving stress field indicates that the influence of the kovada stress regime fades through time and that the influence of the burdur stress regime is gaining importance suggesting a northeastwards progression of the fethiye burdur fault zone

magnetostratigraphy based astronomical tuning of the early pliocene lacustrine sediments of ptolemais nw greece and bed to bed correlation with the marine record continental deposits from the early pliocene lacustrine ptolemais basin in nw greece display rhythmical alternations of lignite and marl beds three parallel sections from this area are studied using magnetostratigraphy and cyclostratigraphy the presence of the greater part of the gilbert chron enables the recognition of astronomical periodicities in the succession especially the precessional influence is evident as it determines the lithological cycles the continental ptolemais composite section is correlated to the most recent astronomical time scale and thus to the marine reference section the rossello composite from sicily c g langereis f j hilgen the rossello composite a mediterranean and global reference section for the early to early late pliocene earth planet sci lett 104 1991 211 225 on a bed to bed scale it is concluded that lignite corresponds to an insolation minimum beige layer in the rossello composite and marl to an insolation maximum grey layer in the rossello composite this implies a precipitation increase during insolation maxima in early pliocene continental greece 1998 elsevier science b v all rights reserved

tectonic and hydrologic controls on cyclic alluvial fan fluvial and lacustrine rift basin sedimentation jurassic lowermost cretaceous todos santos formation chiapas mexico abstract the nonmarine upper jurassic lowermost cretaceous todos santos formation of central chiapas mexico was deposited in half graben basins formed during the early rifting stage of the southern gulf of mexico basin this formation consists of alluvial fan fluvial and lacustrine sequences that were deposited under arid climatic conditions alluvial fans were built outwardly from the elongate basin margins by runoff that flowed transverse to the basin axis whereas fluvial units were deposited by rivers that flowed parallel to the basin axis lacustrine deposition took place in a topographic depression adjacent to the basin margin the presence of alluvial fan and fluvial or lacustrine deposits in vertically stacked cyclic megasequences hundreds of meters thick indicates that the basin opography changed through time this cyclicity denotes that periodically fluvial or lacustrine environments occupied the basin margin position and at other times alluvial fan sedimentation occurred there cyclicity was caused by periodic changes from high to low rates of basin subsidene the response of these three depositional environments to basin subsidence differed due to the unique hydrologic controls on sediment transport and deposition in each environment lakes were maintained by springs that emanated from the fractured fault margin and by fluvial discharge fluvial discharge and deposition resulted from precipitation or annual snowmelt anywhere in the river s expansive drainage basin whereas alluvial fan sedimentation occurred only when there was infrequent significant precipi ation in the small drainage basin from which fan sediment was derived as a result of these hydrologic controls the lacustrine or fluvial environments responded more quickly to periods of active tectonic subsidence and migrated over the fans to occupy the basin margin depression aided by a decrease in basin subsidence alluvial fans eventually prograded and displaced the fluvial or lacustrine environments away from the basin margin

late miocene to early pliocene chronostratigraphic framework for the dacic basin romania abstract new magnetostratigraphic results and calcareous nannofossil data of seven sections in the dacic basin of southern romania covering the latest maeotian to early romanian time span 6 4 4 0 ma allow a correlation with the current astronomical polarity time scale this establishes a chronological framework for the pontian and dacian stages of the paratethys and facilitates to correlate the paratethys stages with those of the mediterranean the maeotian pontian boundary is estimated at 6 15 0 11 ma within subchron c3an 1n while the age of the pontian dacian boundary is 5 30 0 1 ma within subchron c3r the odessian portaferrian and portaferrian bosphorian substage boundaries can be placed at about 6 0 and 5 6 ma at the base and near the end of chron c3r respectively consequently the pontian stage has a duration of approximately 0 85 myr and is coeval with the upper half of the messinian stage the base of the dacian stage corresponds to the onset of the pliocene and is coeval with the pontian kimmerian boundary of the euxinic black sea basin the dacian romanian boundary is recorded either at 4 58 0 05 ma in subchron c3n 2n nunivak or at 4 25 0 05 ma in subchron c3n 1n cochiti the length of the dacian stage is therefore about 0 7 myr or approximately 1 ma the transition of the getian into the parscovian substage can be dated at 4 83 ma within subchron c3n 3n sidufjall or at 4 55 ma within subchron c3n 2n nunivak the occurrence of calcareous nannofossil assemblages in the lower portaferrian and near the portaferrian bosphorian transition belonging to the upper part of the discoaster quinqueramus nn11 zone and in the middle bosphorian belonging to the amaurolithus tricorniculatus nn12 zone indicates the presence of ephemeral marine connections between the paratethys basin and the mediterranean during the late messinian another marine influx inferred from nannofossil species characteristic of the nn12 zone and found in lower dacian sediments near the top of subchron c3n 4n thvera post dates the basal pliocene transgression of the mediterranean basin

alternate interpretation of the messinian salinity crisis controversy resolved a high resolution chronology of the mediterranean messinian salinity crisis is proposed two types of evaporite deposition may be distinguished those in marginal areas vs those in basinal ones their diachroneity is deduced from the stratigraphic relationships linking these evaporites to a major messinian erosional surface a two step model is proposed for the evolution of the salinity crisis through time during the first phase from 5 75 to 5 60 ma the deposition of marginal evaporites took place in response to a modest sea level fall in the second interval from 5 60 to 5 32 ma the mediterranean basin became isolated during this later period the deposition of basinal evaporites and the cutting of the mediterranean canyons took place

fault block rotations at the edge of a zone of continental extension southwest turkey the ne sw trending burdur acigol and baklan basins of southwest turkey are bounded by normal faults which became active in quaternary times prior to this a more widely spaced system of pliocene basins had existed each of the quaternary basins has a half graben geometry with a major nw dipping fault on its southeast side previous studies of the 1971 burdur earthquake caused by movement on the fault bounding the burdur basin have shown this fault to flatten slightly at depth deformation in the hangingwall of the fault controlling the pliocene basin in the burdur region suggests a planar fault geometry it is suggested that the pliocene fault rotated to its present shallow orientation then became inactive and acted as a detachment at depth for the more recent quaternary fault quaternary faults bounding the burdur acigol and baklan basins have a sinistral strike slip component with slip vectors indicating extension in an nw se direction this is at variance with regional n s extension in western turkey a solution for this contrast is found by invoking block rotations about vertical axes in a deforming zone between the rapidly extending aegean region to the west and the stable unstretched anatolian plateau to the east

messinian events in the black sea past hydrological interactions between the mediterranean sea and black sea are poorly resolved due to complications in establishing a high resolution time frame for the black sea we present a new greigite based magnetostratigraphic age model for the mio pliocene deposits of dsdp hole 380 380a drilled in the southwestern black sea this age model is complemented by 40ar 39ar dating of a volcanic ash layer allowing a direct correlation of black sea deposits to the messinian salinity crisis msc interval of the mediterranean sea proxy records divide these dsdp deposits into four intervals i pre msc marine conditions 6 1 6 0 ma ii highstand fresh to brackish water conditions 6 0 5 6 ma iii lowstand fresh water environment 5 6 5 4 ma and iv highstand fresh water conditions 5 4 post 5 0 ma our results indicate the black sea was a major fresh water source during gypsum precipitation in the mediterranean sea the introduction of lago mare fauna during the final stage of the msc coincides with a sea level rise in the black sea across the mio pliocene boundary sea level and salinity in the black sea did not change significantly

neogene evolution of the denizli region of western turkey the denizli region contains one of the easternmost neogene sedimentary basins in the part of western turkey that takes up ssw extension this isolated active normal fault zone which contains closely spaced en echelon normal fault branches is investigated using field measurements of fault exposures and tilted sediments and seismological observations as a case study to address its style of extension the denizli basin is no more than 1 km thick and has accommodated up to 4 km of extension substantial 20 sediment dips are readily explicable assuming extension is accompanied by distributed vertical simple shear with initial and present day dips of the main normal faults that control extension most likely 54 57 and 45 50 other aspects of the form of this basin require regional uplift at 0 1 mm yr 1 providing the first indication of major tectonic elevation changes in this actively extending region that are not directly related to throw on normal faults

palaeoenvironment assessment of pliocene lom lignite bulgaria from bitumen analysis and preparative off line thermochemolysis abstract the dacian coal bearing province is located in nw bulgaria coal formation is thought to be connected with desiccation of the dacian basin during a prolonged regression in the late pontian and pliocene dacian romanian age a lom lignite sample was characterized via micropetrography bulk chemical analysis spectral methods and thermochemolysis the pollen record was poor suggesting coal formation under oxygen rich conditions during peatification straight chain alkanes alkan 2 ones alkanols des a triterpenoids aromatized triterpenoids aromatized hopane hopene hopanes and triterpenoids with a strong dominance of oleanane derived structures were present in the extracted bitumen the residue after extraction was subjected to preparative off line tetramethylammonium hydroxide tmah thermochemolysis the aliphatic products released were c22 c27 fatty acid fa methyl esters i e methoxymethyl esters c22 c28 even numbered diacids dimethyl esters with a smooth distribution and traces of i and ai c15 acid methyl esters trapped and bound fas were distinguished using tetraethylammonium acetate teaac treatment the main thermochemolysis products were phenols structurally related to lignin vanillyl and syringyl units were produced in similar amounts indicating nonwoody angiosperm vegetation as the main plant input to the palaeo swamp probably originating from marsh or grassland sources the bitumen provided unequivocal information for an angiosperm contribution to the mire while the results of the tmah pyrolysis revealed a concomitant angiosperm and gymnosperm input the biomarker assemblage makes the lom lignite unique in bulgaria all the other bulgarian neogene lignites being dominated by coniferous vegetation with only traces of angiosperm contributions

high resolution analysis of upper miocene lake deposits evidence for the influence of gleissberg band solar forcing article i nfo a high resolution multi proxy analysis was conducted on a 1 5 m long core of tortonian age 10 5 ma late miocene from austria europe the lake sediments were studied with a 1 cm resolution to detect all small scale variations based on palynomorphs pollen and dinoflagellate cysts ostracod abundance geochemistry carbon and sulfur and geophysics magnetic susceptibility and natural gamma radiation based on an already established age model for a longer interval of the same core this sequence can be limited to approx two millennia of late miocene time with a resolution of 13 7 years per sample the previous study documented the presence of solar forcing which was verified within various proxies on this 1 5 m core by a combination of redfit spectra and gaussian filters significant repetitive signals ranged in two discrete intervals corresponding roughly to 55 82 and 110 123 years fitting well within the lower and upper gleissberg cycle ranges based on these results the environmental changes along the 2000 year late miocene sequence are discussed no major ecological turnovers are expected in this very short interval nonetheless even within this brief time span dinoflagellates document rapid changes between oligotrophic and eutrophic conditions which are frequently coupled with lake stratification and dysoxic bottom waters these phases prevented ostracods and molluscs from settling and promoted the activity of sulfur bacteria the pollen record indicates rather stable wetland vegetation with a forested hinterland shifts in the pollen spectra can be mainly attributed to variations in transport mechanisms these are represented by a few phases of fluvial input but mainly by changes in wind intensity and probably also wind direction such influence is most likely caused by solar cycles leading to a change in source area for the input into the lake furthermore these solar induced variations seem to be modulated by longer solar cycles the filtered data display comparable patterns and modulations which seem to be forced by the 1000 year and 1500 year cycles the 1000 year cycle modulated especially the lake surface proxies whereas the 1500 year cycle is mainly reflected in hinterland proxies indicating strong influence on transport mechanisms

experimental investigation of sediment dominated vs tectonics dominated sediment transport systems in subsiding basins abstract models of stratigraphic architecture make testable predictions regarding the subsurface spatial density and connectivity of channel sandstone bodies in subsiding basins here we test one of these predictions that lateral gradients of subsidence rate in alluvial basins tend to draw channels to local subsidence maxima and thus increase the subsurface stacking density of channel sand bodies in the vicinity of subsidence maxima here we define channel steering as any change in channel course due to lateral gradients in subsidence focusing on the attraction of channels to regions of high subsidence we examine the hypothesis that steering is controlled by the tilting ratio the ratio of the rate of lateral tilting to that of lateral channel mobility with steering effects expected to increase as the tilting ratio increases we present measurements of channel steering from experiments in which we varied the tilting ratio over four stages the experiments used a relay ramp geometry with laterally variable uplift and subsidence initially with a small value of the tilting ratio we did not detect noticeable channel steering through reductions in input sediment discharge qs and water discharge qw we decreased channel mobility in later stages while keeping the subsidence regime the same this resulted in systematic increases in the tilting ratio and in observable steering towards regions of high subsidence interestingly the increase in tilting rate relative to channel mobility also resulted in a preference for channel occupation over uplift regions as channels were trapped by incision into the rising surface we also develop theory to predict when the strength and duration of pulsed tilting events are sufficient to steer channels as with the theory for steady subsidence the new theory suggests that pulsed events must be strong enough and long lived enough to produce comparable cross basin to down basin transport slopes an experimental stage with pulsed tectonics supports this theory finally we document autogenic shoreline transgressions in the relay zone during deformation these transgressions produce downstream to upstream facies translation of the sand coal boundary in the preserved stratigraphy and illustrate a mechanism by which transgressions can develop without external cause

the pulse of calm fan deltas abstract at the heart of interpreting the history of earth surface evolution preserved in the rock record is distinguishing environmental allogenic forcing from internally generated autogenic noise allogenic deposits classically have been recognized by their cyclic nature which apparently results from periodic changes in base level sediment supply or tectonics autogenic deposits which are quite variable in their origin and scale are caused by the nonlinearity of sediment transport and might be expected to have a random or scale free fractal signature here we describe a robust mechanism that generates cyclic deposits by an autogenic process in experimental fan deltas sheet flow over the fan surface induces deposition and an increase in fluvial slope and curvature to a point where the surface geometry is susceptible to a channelization instability similar to channel initiation on hillslopes channelized flow results in incision and degrading of the fan surface to a lower slope releasing a

vegetation and palaeoclimate in the miocene of ukraine miocene deposits marine and terrestrial distributed throughout the whole territory of ukraine contain numerous palaeontological remains including plant macro and microfossils there are well known occurrences of fossil leaves as well as fruits and seeds the miocene strata of ukraine belong to the central and the eastern paratethys and deposits from these regions have been studied palynologically for the reconstruction of the vegetation of lowland and mountain areas in ukraine palynological data have been complemented with data obtained from carpological and foliar studies to obtain quantitative climate data microfloral records from the ukraine plain and the ukrainian carpathians are analyzed using the coexistence approach the main trends of floral changes were directed by the global climate evolution complicated by regional tectonic processes major vegetation change occurred during the late miocene cooling in southern ukraine the cooling was accompanied by a gradual drying and partial replacement of forest vegetation by herbaceous communities that increased in richness and expanded from east to west

development of tectonic cyclothems in rift pull apart and foreland basins sedimentary response to episodic tectonism the thickest part of asymmetric rift pull apart and foreland basin fills commonly consists of large scale hundreds to thousands of metres thick tectonically generated cyclothems of fine grained marine lacustrine or longitudinal fluvial deposits and coarse grained transverse braid plain or alluvial fan deposits the appearance of coarse clastics in these basin fills is typically noted as the time of tectonically rejuvenated source area uplift based on the conceptual tie between relief and coarse grain size and on the application of the davis theory of landform development we propose the opposite interpretation that the commencement of fine grained sedimentation above coarse grained deposits in a tectonic cyclothem is the best indicator of renewed tectonic activity this reinterpretation is more consistent with 1 modern examples 2 the consideration of source area and sedimentary basin geomorphology 3 the disparity between the reaction rates of the various environments to subsidence 4 the disparity between the rates of tectonic uplift and erosion and 5 the controls on elastic wedge progradation in our model extensive coarse grained clastic wedge progradation is an indicator of tectonically quiescent phases

strontium isotope ratios of the eastern paratethys during the mio pliocene transition implications for interbasinal connectivity paratethys represents the large basin that extended from central europe to inner asia comprising the north alpine foreland pannonian and dacian basins the black sea and caspian sea connectivity between these subbasins and the connectivity of paratethys with the open ocean varied drastically because of pervasive tectono climatic processes affecting the region here we investigate the biogenically produced carbonates of the dacian basin for strontium analyses to monitor changes in connectivity water geochemistry and palaeoenvironment during the mio pliocene transition diagenetic evaluation showed that not all contamination could be removed but that the strontium content of our samples was not affected by post depositional processes 87sr 86sr ratios of ostracods and molluscs are in good agreement and show relatively constant values of 0 70865 0 70885 these are much lower than coeval mio pliocene ocean water 0 7089 0 7090 which indicates that no long standing connection existed to the mediterranean the newly obtained strontium ratios for paratethys are best explained by a mixture of danube dnieper and don river waters implying connectivity between dacian basin and black sea during the latest miocene earliest pliocene we observed no evidence for connectivity to the caspian sea during this period the 87sr 86sr ratios of the dacian basin are similar to the ones measured in the mediterranean upper evaporites lago mare facies the major fresh water deluge at the end of the messinian salinity crisis could thus have been caused by drowning of eastern paratethys waters into the mediterranean

variability in fluvial geomorphic response to anthropogenic disturbance abstract humans have greatly impacted the processes and intensities of erosion sediment transport and storage since the introduction of agriculture in many regions around the world accelerated floodplain sedimentation can be related to increases in human pressure on the environment however the relation between the intensity of anthropogenic disturbance and the magnitude of change in fluvial sediment dynamics is not straightforward and often non linear here we review a number of case studies from contrasting environmental settings in the european loess belt the eastern mediterranean mountain ranges and the eastern usa detailed field based sediment archive studies and sediment budgets covering time periods ranging from 200 to over 5000 year as well as the use of pollen and sediment provenance techniques show that no overarching concept of changes in floodplain sedimentation following anthropogenic disturbance can be established slope channel dis connectivity controls the existence of thresholds or tipping points that need to be crossed before significant changes in downstream sediment dynamics are recorded following human impact this coupling can be related to characteristics of human pressure such as its duration intensity and spatial patterns but also to the geomorphic and tectonic setting furthermore internal feedback mechanisms such as those between erosion and soil thickness further complicate the story all these factors controlling the propagation of sediment from eroding hillslopes to river channels vary between regions hence only unique patterns of fluvial geomorphic response can be identified as a result unravelling the human impact from current day sediment archives and predicting the impact of future human disturbances on fluvial sediment dynamics remain a major challenge this has important implications for interpreting contemporary sediment yields as well as downstream sediment records in large floodplains deltas and the marine environment in terms of changes in the drivers of environmental change

comment on miocene to quaternary tectonostratigraphic evolution of the middle section of the burdur fethiye shear zone south western turkey implications for the wide inter plate shear zones tectonophysics 690 336 354