orbitally forced climate signals in mid pliocene nannofossil assemblages downcore cyclic variation in high resolution nannofossil abundance records from mid pliocene equatorial atlantic odp sites 662 and 926 demonstrate the direct response by several pliocene taxa notably discoaster sphenolithus and florisphaera profunda to orbitally forced climatic variation in particular these records display strong obliquity and precessional signals reflecting primarily high latitude southern hemisphere changes influencing upwelling intensity and local low latitude insolation driven climatic changes via the productivity and or turbidity influence of amazon sourced terrigenous material at sites 622 and 926 respectively in seasonal studies of coccolithophorid assemblages only part of the variation observed can be explained by abiotic processes so it is perhaps not surprising that in this study few pliocene nannofossil taxa demonstrate significant correlations with each other or with physical environmental parameters only some variance in nannofossil abundances can be explained by the primary controls of temperature and productivity the rest is attributed to nonlinear responses to climatic changes biotic processes such as grazing predation viral infection and competition and or abiotic factors for which there is no readily available proxy e g salinity the lack of strong consistent intra and inter relationships of the nannoflora and the environment reflects an ecologically complex differentiated original community producing a complex integrated signal transmitted into the fossil record

experimental investigation of controls on cementation in carbonates experiments simulating carbonate diagenesis have been performed using natural oolitic and skeletal sediments in seawater at temperatures of 183 186 c and hydrostatic pressures of 6 10 mpa during the experiments both equant and granular columnar calcite cements were precipitated equant cements developed when both nucleation and growth rates were low due to mg 2 inhibition or to lower rates of caco 3 supply via aragonite dissolution the data show that the mg ca ratio of the pore fluid does not control calcite morphology directly during the experiments but rather the morphology is a function of nucleation and growth rate it is also suggested that the presence of organic matter may aid nucleation of caco 3

central european vegetation response to abrupt climate change at 8 2 ka oxygen isotope records show a major climatic reversal at 8 2 ka in greenland and europe annually laminated sediments from two lakes in switzerland and germany were sampled contiguously to assess the response of european vegetation to climate change ca 8 2 ka with time resolution and precision comparable to those of the greenland ice cores the pollen assemblages show pronounced and immediate responses 0 20 yr of terrestrial vegetation to the climatic change at 8 2 ka a sudden collapse of corylus avellana hazel was accompanied by the rapid expansion of pinus pine betula birch and tilia linden and by the invasion of fagus silvatica beech and abies alba fir vegetational changes suggest that climatic cooling reduced drought stress allowing more drought sensitive and taller growing species to out compete corylus avellana by forming denser forest canopies climate cooling at 8 2 ka and the immediate reorganization of terrestrial ecosystems has gone unrecognized by previous pollen studies on the basis of our data we conclude that the early holocene high abundance of c avellana in europe was climatically caused and we question the conventional opinion that postglacial expansions of f silvatica and a alba were controlled by low migration rates rather than by climate the close connection between climatic change and vegetational response at a subcontinental scale implies that forecasted global warming may trigger rapid collapses expansions and invasions of tree species

miocene transgression in the central and eastern parts of the sivas basin central anatolia turkey and the cenozoic palaeogeographical evolution we present here a reappraisal of the tectonic setting stratigraphy and palaeogeography of the central part of the sivas basin from palaeocene to late miocene the sivas basin is located in the collision zone between the pontides southern eurasia and anatolia a continental block rifted from gondwana the basin overlies ophiolites that were obducted onto anatolia from tethys to the north the central anatolian crystalline complex cacc experienced similar ophiolite obduction during campanian time followed by exhumation and thrusting onto previously emplaced units during maastrichtian time to the east crustal extension related to exhumation of the cacc created grabens during the early tertiary including the sivas basin the sivas basin underwent several tectonic events during paleogene neogene the basin fill varies with several sub basins each being characterised by a distinctive sequence especially during oligocene and miocene evaporite deposition in the central part of the basin during early oligocene was followed by mid late oligocene fluvio lacustrine deposition the weight of overlying fluvial sediments triggered salt tectonics and salt diapir formation lacustrine layers that are interbedded within the fluviatile sediments have locally yielded charophytes of late oligocene age emergent areas including the pre existing sivas basin and neighbouring areas were then flooded from the east by a shallow sea giving rise to a range of open marine sub basins coralgal reef barriers and subsiding restricted marine sub basins utilising new data from foraminifera molluscs corals and nannoplankton the age of the marine transgression is reassessed as aquitanian specifically age diagnostic nannoplankton assemblages of classical type occur at the base of the transgressive sequence however classical stratigraphic markers have not been found within the planktic foraminiferal assemblages even in the open marine settings in the restricted marine sediments there are rich planktic foraminiferal assemblages of classical type but these are of little use in stratigraphy in contrast the gastropod fauna indicate a burdigalian age sediment reworking in the restricted marine environments precludes stratigraphic determination in such environments micro and nano organisms experienced atypical developmental conditions the small benthic foraminifera and associated ostracod assemblages are good indicators of salinity which varied considerably within the restricted marine sub basins some of the corals within the coralgal reefs barriers are also dated as aquitanian a combination of the salt tectonics and the late miocene north westward verging thrusting created the present basin complexity

climate stability in central anatolia during the messinian salinity crisis abstract deposition of large amounts of evaporites and erosion of deep canyons within the mediterranean basin as a result of reduced basin connectivity with the atlantic ocean and the epicontinental paratethys sea characterized the messinian salinity crisis msc 5 97 5 33 ma the influence of the msc on mediterranean environmental conditions within the basin itself has been intensely studied from marine records but reconstructing the impact of the msc on circum mediterranean continental climate has been hampered by the absence of continuous sedimentary archives that span the duration of the event here we report results of a continental record of carbon 13c and oxygen 18o isotopes from lake carbonates framed by new magnetostratigraphic and 40ar 39ar dating as well as by existing mammal stratigraphy kangal basin central anatolia the sampled section records continuous fluvio lacustrine sedimentation from 6 6 ma to 4 9 ma which spans the msc and the miocene pliocene boundary this dataset so far represents the only continuous continental paleoenvironmental record of the msc in the circum mediterranean realm the kangal basin isotope record indicates a low degree of evaporation furthermore covariance between 13c and 18o suggests a coupling between lake water balance and biologic productivity variations in 13c and 18o therefore likely reflect changes in the amount of incoming precipitation rather than changes in 18o values of incoming precipitation the most prominent spike in 13c and 18o occurs during the acme of the msc and is therefore interpreted to have resulted from a decrease in the amount of incoming moisture correlative to a period of vigorous erosion and sea level lowering in the mediterranean basin major sea level lowering of mediterranean basin waters during the acme of the msc could have therefore led to slightly dryer conditions over anatolia which is also suggested by modeling studies overall changes in 13c and 18o values are small therefore we surmise that the msc had limited effects on the paleoenvironmental and paleoclimatic conditions in the anatolian interior

biostratigraphy of the last glacial period in europe the european early weichselian early wurmian is characterized by two long and relatively warm interstadials brorup and odderade which can be traced and correlated with certainty across large parts of europe the amersfoort interstadial described earlier from the netherlands has been included in the brorup and represents the older part of it both great interstadials were forested in north west central and southern europe in the north conifer forests prevailed giving way towards the south to deciduous forests the climatic gradient was distinctly steeper mainly due to southward displacement of the gulf stream the two great interstadials are synchronous with the isotopic stages 5a and 5c in the deep sea cores subsequent to eemian brorup and odderade and from within the context of a continuous series two additional and clearly delimited interstadials have been recorded in a new standard profile from oerel nw germany these are now described as the oerel and glinde interstadials they were not forested and belong to the early pleni weichselian the lower one oerel can probably be correlated with the 3rd weichselian wurmian interstadial in southern central europe ognon ii durnten samerberg 3 while the upper one glinde has so far no known counterpart for the younger pleni glacial it is assumed that there was a long phase during which it was not too cold the formation of humic layers during this phase took place at different times partly due to local edaphic factors so that the relevant 14c dates show a wide scatter the hengelo and denekamp interstadials represent only slight ameliorations which facilitated the formation of shrub tundra and can be recorded in certain regions only

palaeoclimatic evolution and vegetational changes during the late oligocene miocene period in western and central anatolia turkey abstract neogene basins are widespread in turkey and contain important lignite deposits in this study we reconstruct quantitatively the late oligocene miocene climate evolution in western and central anatolia by applying the coexistence approach to the palynofloras obtained from the published literatures and ongoing studies the coexistence approach results show that sedimentation occurred mainly under warm subtropical climatic conditions during the chattian and aquitanian period in western anatolia 16 5 21 3 c mean annual temperature mat and 5 5 13 3 c mean temperature of coldest month cmt rare occurrences of dinoflagellate cysts in the chattian and aquitanian indicates a marine influence after the regression of the sea during the burdigalian period climate becomes cooler due to a decrease of the palaeotropical arctotertiary ratio during the latest burdigalian langhian vegetation developed under terrestrial conditions which had started in the burdigalian time in western and central anatolia and continued to the early middle serravallian period the climate was subtropical in western and central anatolia during the early late serravalian 17 2 to 20 8 c for mat and 9 6 to 13 1 c for cmt besides increase of the cmt and mat values in western and central anatolia supports the latest chattian earliest aquitanian warming and middle miocene climatic optimum being also globally observed warm temperate climatic conditions are observed in the late miocene during the early middle tortonian the values are 15 6 to 20 8 c for the mat 5 5 to 13 3 c for the cmt and 823 and 1520 mm for the mean annual precipitation map they had experienced dry seasons due to lower boundary of map lying at 823 mm during the middle late tortonian the palaeotopography of central anatolia was higher compared to that of western anatolia during the middle late miocene as indicated by a rich species diversification in mountain forests this study provides the first quantitative model for late oligocene miocene palaeoclimatic evolution in western and central anatolia

paleoclimate and paleoceanography over the past 20 000 yr in the mediterranean sea basins as indicated by sediment elemental proxies abstract marine sediments record paleoenvironmental changes over time through variations in major and trace element concentrations the main objective of this paper is to review such changes in the mediterranean sea basins over the last 20 ka using the inorganic chemistry and mineralogy of marine sediment records elemental ratio proxies that are mostly used are discussed and the uncertainties involved in using them for paleoclimate and paleoceanographic reconstructions are evaluated the focus on the mediterranean region is based on the sensitivity of this region to global climate changes due to its semi enclosed nature the elemental ratios that have been particularly useful for reconstructing terrigenous inputs into the mediterranean have been ti al and zr al ratios as proxies for eolian dust input and mg al k al and rb al ratios as proxies for fluvial input redox sensitive elements e g u mo v co ni cr have provided reliable reconstructions of oxygen conditions at the time of deposition some of these elements are also particularly susceptible to post depositional remobilization and record diagenetic processes instead of the original environmental signatures regarding productivity fluctuations most of the paleoproductivity reconstructions are based on the abundance of barite and ba excess algorithms the biogeochemistry of ba is however not fully understood and mechanisms for barite precipitation in the water column are not yet known two case studies are presented the eastern mediterranean sapropel s1 deposited between 10 8 and 6 1 cal ka bp and the westernmost mediterranean paleoclimate record over the last 20 ka

tertiary evolution of the sivas basin central turkey abstract the sivas basin is one of several basins in turkey formed during closure of the northern branch of neotethys in early tertiary times cretaceous ophiolitic fragments and eocene platform carbonates and volcaniclastics transported northwards into the basin as olistoliths and grain flow aprons were incorporated into autochthonous eocene turbidites and bioclastic limestones the sequence as a whole was thrust northwards in late eocene times a southward sloping terrestial foreland basin related to northward directed thrusting developed during oligocene times a piggy back basin developed on top of this thrust system during the late oligocene the eocene thrusts were reactivated probably resulting in northward propagation of thrusts in the subsurface in early and mid miocene times the basin was floored by a thrust sheet which had been cut by n s trending tear faults or oblique culminations as a result of non uniform thrust advance in pre miocene times these n s faults were subsequently reactivated as extensional faults radial to the thrust front during early to mid miocene alluvial and shallow marine sedimentation later strike slip displacement along the n s faults was associated with the development of the northern boundary fault of the sivas basin in late miocene times which is regarded as a left lateral transpressive fault related to the north anatolian fault zone

evidence for eutrophication in the northwestern pacific and eastern indian oceans during the miocene to pleistocene based on the nannofossil accumulation rate discoaster abundance and coccolith size distribution of reticulofenestra abstract to reconstruct the cenozoic paleoceanographic evolution in particular temporal changes in nutrient levels we studied calcareous nannofossil assemblages from ocean drilling program holes 1210a located in the northwestern pacific ocean and 762b situated in the eastern indian ocean at each site we focused on the relationships among the nannofossil accumulation rate nar relative abundance of discoaster and coccolith size of the genus reticulofenestra the co occurrence of a low nar high discoaster abundance and presence of large reticulofenestra suggest a deep thermocline and nutricline typical of oligotrophic conditions conversely the co occurrence of a high nar low discoaster abundance and presence of small reticulofenestra indicate a shallow thermocline and nutricline typical of eutrophic conditions the combination of these three parameters suggests that the gradual eutrophication and collapse of sea surface stratification occurred in the northwestern pacific ocean at 7 9 6 4 and 5 0 ma in contrast abrupt eutrophication is indicated at 8 8 ma in the eastern indian ocean although the timing of eutrophication differs between the pacific and indian ocean sites it roughly coincides with tectonic and or climatic events around the two oceans this finding suggests that tectonic and climatic events are capable of causing an increase in the terrestrial input and or coastal upwelling of nutrients that subsequently leads to the eutrophication of sea surface waters

clastic petrofacies provenance and organic facies of the bozbel formation lutetian in the eastern sivas basin turkey abstract the bozbel formation lutetian of the eastern part of the sivas basin central anatolia turkey displays a range of lithofacies which vary greatly in thickness the formation consists of conglomerates sandstones mudstones and shales marls limestones and sandy limestones clayey limestones tuffites and volcanic breccias the aim of this study is to determine the clastic petrofacies of the sandstones and to describe the characteristics of the organic facies and source rocks present in the bozbel formation the sandstones can be classified essentially as arkoses lithic arkoses and feldspathic litharenites cement rich and containing minor amounts of olivine pyroxene chlorite biotite muscovite and opaque minerals these sands were derived from magmatic arc and mixed provenances the source rock characters of the finer grained bozbel rocks and their organic facies have been determined by means of total organic carbon t o c analyses rock eval pyrolysis vitrinite reflectance data and clay mineral paragenesis together with illite crystallinity values the organic matter content is dominated by type 3 kerogen illite crystallinity indices and vitrinite reflectance data run parallel with each other and are consistent with the catagenetic stage of organic matter evolution the bozbel formation in the south hafik region is appropriately mature to yield hydrocarbons but because of the generally low content of organic matter it is unlikely to have generated petroleum but is known to be gas prone

the holocene and upper pleistocene pollen record from padul granada spain a new study two borings were made at the site of padul granada pollen analysis of 200 spectra from two successive sequences 14 8 and 8 m deep enables a description of the vegetational and climatic history of this region the most southern one in europe from early wurmian times the chronology is supported by twenty one 14c dates original equivalents are found for the great european prewurm interstadials a markedly arid though thermically not extreme episode exactly equivalent to stage 4 of the marine isotopic stratigraphy closes this relatively temperate period the middle part of the last glacial shows climatic fluctuations that are poorly characterized as is often the case in europe for this period a long section very probably corresponding to the complete last pleniglacial does not show any climatic amelioration towards 15 000 yr b p a change in the diagram is noted that can only be interpreted as reflecting a larger expansion of a regional steppe cover this event also reported on three occasions in southeast france marks the beginning of the oldest dryas the climatic amelioration of ca 13 000 yr b p is far more pronounced here than anywhere else in europe whereas that at 10 000 yr b p is not so clearly marked this unexpected result may be accounted for by the fact that padul is the first continental site so far south and so near pleniglacial refuges to be known on the other hand this result is consistent with what is known from oceanic isotopic stratigraphy a quite new late glacial and holocene vegetational history is revealed characterized by the early appearance and dominance of quercus ilex oak forests of a southern type and the early occurrence of quercus suber and olea it is the first account of a complete history of the postglacial reafforestation in a region with a modern semi arid mediterranean climate from the palaeoclimatic point of view it shows that the hot and humid holocene optimum was attained slightly before 8000 yr b p and that the holocene climatic fluctuations were of but small amplitude

an evaluation of geochemical weathering indices in loess paleosol studies abstract applying geochemical proxies as measure for the weathering intensity of paleosols and sediments such as loess the quaternary scientist is confronted with various element ratios that have been proposed in literature this paper gives an overview on the principle of geochemical weathering indices different types of indices are evaluated with respect to the suitability for loess paleosol sequences regarding the special characteristics of this type of sediments and paleosols case examples in this study are key sections in southeastern and eastern europe the loess paleosol sequences batajnica stari slankamen serbia mircea voda romania and stary kaydaky ukraine which represent archives of the late and mid pleistocene climate change of the region considering element behavior during weathering or diagenesis the chemical proxy of alteration cpa i e the molar ratio al2o3 al2o3 na2o 100 is proposed as the most appropriate index for silicate weathering the cpa was evaluated against commonly used weathering indices including the chemical index of alteration cia the chemical index of weathering ciw the plagioclase index of alteration pia the index b of kronberg and nesbitt and the ba sr and rb sr ratio depth profiles of sr type indices e g ba sr rb sr are likely to be influenced by the dynamics of secondary carbonate on the other hand common na type indices e g cia pia ciw may suffer from uncertainties in separating carbonate ca from silicate ca or from biases due to k fixation illitization the cpa is insensitive against such effects additionally using the cpa as with other na type indices provides the possibility to evaluate the homogeneity of the parent material regarding the relevant host minerals via the a cn k diagram

biogeographic gradients of middle eocene oligocene calcareous nannoplankton in the south atlantic ocean middle eocene oligocene calcareous nannoplankton have been analyzed quantitatively for eight dsdp and odp sites ranging from the equatorial zone to 65 s latitude in the south atlantic ocean there is a general decrease in calcareous nannoplankton species diversity from the middle eocene through the oligocene and species diversity also decreases towards the higher latitudes similar to findings of other studies the drop of the species diversity of calcareous nannoplankton across the eocene oligocene boundary is not drastic delineation of latitudinal distribution patterns of individual species or groups and r mode cluser analysis permit the classification of warm water taxa coccolithus formosus discoasters helicosphaerids and sphenoliths temperate water taxa coccoliths pelagicus cyclicargoliths floridanus group reticulofenestra bisecta reticulofenestra samodurovii reticulofenestra umbilica and cool water taxa chiasmoliths isthmolithus recurvus and reticulofenestra daviesii the abundance of warm water taxa plummets whereas the abundance of cool water taxa sharply increases across the eocene oligocene boundary at the middle and high latitude sites reflecting a profound cooling event in these areas polar ordination and similarity analyses reveal that steep latitudinal biogeographic gradients had been established at least by the middle eocene the gradient greatly increases near the eocene oligocene boundary indicating more severe and permanent cooling at the high latitudes the biogeographic gradient data of this study conflict with the widely accepted inference from the oxygen isotopic data that the thermal gradients between mid latitudes and high latitudes are low or nearly flat for the paleogene oceans lower surface water salinities in the high latitudes may have lowered the 18o values of the planktonic microfossils but apparently did not have significant effect on latitudinal distribution patterns of calcareous nannoplankton which offers an independent means for estimating latitudinal thermal gradients

vegetation response to rapid climate change in central europe during the past 140 000 yr based on evidence from the furamoos pollen record the response of central european vegetation to rapid climate change during the late quaternary period eemian to holocene is assessed by data from the new pollen record of furamoos southwestern germany this record represents the longest late quaternary pollen record north of the alps as currently known its high degree of completeness allows detailed correlations with greenland ice cores and sea surface temperature records from the north atlantic our data show that if climate deteriorations were not long or severe enough to extirpate refugia of arboreal taxa north of the alps such as during marine oxygen isotope stage mis 5 i e wurm stadial a stadial b and stadial c reforestation with the onset of warmer conditions in central europe occurred on a centennial scale if arboreal taxa became completely extinct north of the alps such as during mis 4 i e wurm stadial d several thousand years were necessary for the reimmigration from refugia situated in regions south of the alps thus dansgaard oeschger interstades dois 24 to 20 and 15 to 11 are expressed in central european pollen records whereas dois 19 to 16 are not recorded due to migration lags

palaeoclimatic interpretation of clay minerals in marine deposits an outlook from the continental origin abstract as distribution of clay minerals in modern oceans seems to be controlled by contemporary climates marine clays in ancient deposits have been widely used to reconstruct palaeoclimates in this review we examine this question mainly from the continental origin of the clay minerals and show the difficulties of retrospective analysis of the influence of climate on common marine deposits we examine successively how soils develop and behave are reworked and palaeoweatherings are preserved focusing the review on kaolinitic soils indicative of tropical wet climates several stages intervene between the time of clay mineral development in soils and their final deposition in the basin 1 the persistence over geological times of huge amounts of kaolinitic palaeoweathering materials in the landscapes may seriously alter the palaeoclimatic signal of kaolinite in the sedimentary record although the kaolinite deposited in recent sediments of the world oceans is consistent with wet climatic zones this is mainly because the major kaolinitic and bauxitic palaeosurfaces coincide with the tropical areas where kaolinite is still developing at present 2 possible development of deep kaolinitic profiles at high latitudes and cold conditions under co 2 enriched palaeoatmospheres or even by unusual acidic weathering linked with dry climates is misleading palaeoenvironments for palaeoclimatic reconstruction 3 erosion and transport processes always cloud the signal to some extent because frequently erosion products from the bedrock and different soil horizons will be mixed and major drainage systems may include soils of different climatic zones 4 the arrival of the soil clay assemblages in the basin inevitably lags against their formation on the continent and may occur several million years after formation of the soils on the continent and climate may have considerably changed at that time it is pointed out that sedimentologists and palaeoclimatologists should consider the complexity of the relations between soil and sedimentary clay minerals soil formation rates are slow and therefore the resolution of the palaeoclimatic record in marine clay may not be closer than 1 or 2 ma at present the palaeoclimatic interpretations of marine clay assemblages are yielding at best nothing more than rather broad palaeoclimatic information this approach cannot achieve the same degree of resolution as other techniques such as isotope or microfossil studies clay mineral assemblages may provide integrated records of overall climatic impacts whereas other techniques are more likely to reveal local or temporary climates

the heartbeat of the oligocene climate system a 13 million year continuous record of oligocene climate from the equatorial pacific reveals a pronounced heartbeat in the global carbon cycle and periodicity of glaciations this heartbeat consists of 405 000 127 000 and 96 000 year eccentricity cycles and 1 2 million year obliquity cycles in periodically recurring glacial and carbon cycle events that climate system response to intricate orbital variations suggests a fundamental interaction of the carbon cycle solar forcing and glacial events box modeling shows that the interaction of the carbon cycle and solar forcing modulates deep ocean acidity as well as the production and burial of global biomass the pronounced 405 000 year eccentricity cycle is amplified by the long residence time of carbon in the oceans

early miocene repetitive vegetation and climatic changes in the lacustrine deposits of the rubielos de mora basin teruel ne spain pollen analysis of a lower miocene succession from the rubielos de mora basin ne spain has been carried out with the aim of reconstructing the flora vegetation and climatic changes previous paleobotanical studies on these sedimentary rocks and adjacent areas interpreted very diverse climates for the early miocene from humid temperate to dry subtropical in this study a rich thermophilous pollen spectrum and a diverse subarid flora including nitraria caesalpiniaceae ephedra and acacia indicative of a dry subtropical climate are identified on the other hand mesothermic taxa with high water requirements are also abundant therefore the pollen assemblages evidence the juxtaposition of very contrasted environments the presence of subdesertic taxa typical of plants growing in the lowlands and conditioned by a long warm dry season together with others with very high water requirements needing constant water this can be explained by the presence of the rubielos de mora lake providing local conditions for developing riparian forests the vegetation was clearly controlled by the water availability under a subtropical and dry seasonal climate pollen changes along the succession which coincide with sedimentological changes are related to climatic variations alternation in pollen taxa thermophilous dry vs mesothermic riparian reflects the influence of the cyclicity of temperature and precipitation on the lake level and vegetation

middle eocene late oligocene climate variability calcareous nannofossil response at kerguelen plateau site 748 a major deterioration in global climate occurred through the eocene oligocene time interval characterized by long term cooling in both terrestrial and marine environments during this long term cooling trend however recent studies have documented several short lived warming and cooling phases in order to further investigate high latitude climate during these events we developed a high resolution calcareous nannofossil record from odp site 748 hole b for the interval spanning the late middle eocene to the late oligocene 42 to 26 ma the primary goals of this study were to construct a detailed biostratigraphic record and to use nannofossil assemblage variations to interpret short term changes in surface water temperature and nutrient conditions the principal nannofossil assemblage variations are identified using a temperate warm water taxa index twwt from which three warming and five cooling events are identified within the middle eocene to the earliest oligocene interval among these climatic trends the cooling event at 39 ma cooling event b is recorded here for the first time variations in fine fraction 18o values at site 748 are associated with changes in the twwt index supporting the idea that significant short term variability in surface water conditions occurred in the kerguelen plateau area during the middle and late eocene furthermore odp site 748 calcareous nannofossil paleoecology confirms the utility of these microfossils for biostratigraphic paleoclimatic and paleoceanographic reconstructions at southern ocean sites during the paleogene

vegetation sea level and climate changes during the messinian salinity crisis the messinian salinity crisis late miocene is one of the most fascinating paleoceanographic events in the recent geological history of the mediterranean sea defining a time when it partly or nearly completely dried out however the relative roles of tectonic processes and sea level changes as triggers for restriction and isolation of the mediterranean sea from the open ocean are still under debate in this study we present a detailed pollen dinoflagellate cyst dinocyst and magnetic susceptibility analysis of a sequence of late neogene between ca 7 3 and 5 2 ma marine sediments from the montemayor 1 core lower guadalquivir basin southwestern spain which provides a continuous record of paleoenvironmental variations in the atlantic side of the betic corridors during the late miocene our results show that significant paired vegetation and sea level changes occurred during the messinian likely triggered by orbital scale climate change important cooling events and corresponding glacio eustatic sea level drops are observed in this study at ca 5 95 and 5 75 ma coinciding with the timing and duration of oxygen isotopic events tg32 and tg22 20 recorded in marine sediments worldwide it is generally accepted that the onset of the messinian salinity crisis began at ca 5 96 0 02 ma therefore this study suggests that the restriction of the mediterranean could have been triggered at least in part by a strong glacio eustatic sea level drop linked to a climate cooling event occurring at the time of initiation of the messinian salinity crisis

orbitally induced climate and geochemical variability across the oligocene miocene boundary to assess the influence of orbital scale variations on late oligocene to early miocene climate and ocean chemistry high resolution 5 kyr benthic foraminiferal carbon and oxygen isotope and percent coarse fraction time series were constructed for ocean drilling program site 929 on ceara rise in the western equatorial atlantic these time series exhibit pervasive low to high frequency variability across a 5 myr interval 20 5 25 4 ma the records also reveal several large scale secular variations including two positive 1 6 oxygen isotope excursions at 22 95 and 21 1 ma suggestive of large but brief glacial maxima mi 1 and mi 1a events of miller et al 1991 and a long term cyclical increase in the carbon isotopic composition of seawater shift of 1 52 that reaches a maximum coincident with peak 18o values at 22 95 ma lower resolution 25 kyr records constructed from benthic and planktonic foraminifera as well as bulk carbonate at a shallower site on ceara rise site 926 for the period 21 7 24 9 ma covary with site 929 18o values reflecting changes in antarctic ice volume likewise covariance among carbon isotopic records of bulk sediment benthic and planktonic foraminifera suggest that the low frequency cycles 400 kyr and long term increase in 13c values represent changes in the mean carbon composition of seawater co2 the time series presented here constitute the longest most continuous and highest resolution records of pre pliocene climate and oceanography to date the site 929 carbon and oxygen isotope power spectra show significant concentrations of variance at 400 100 and 41 kyr demonstrating that orbitally induced oscillations have been a normal characteristic of the global climate system since at least the oligocene including periods of equable climate and times with no apparent northern component water production

recent contributions to the climatology of the last glacial interglacial cycle based on french pollen sequences abstract new pollen data derived from three long french sequences and methodological improvements in the methods used to reconstruct past climates are summarized here after a short presentation of the study sites and pollen diagrams estimated climate parameters during the major episodes of the last 140 000 years are shown to be coherent between sites analysis of the seasonality variations provides much additional information in particular it is shown that the advection from the ocean has governed the last climatic cycle on the european continent

rapid environmental changes in southern europe during the last glacial period oxygen isotope records from greenland ice cores1 2 indicate numerous rapid climate fluctuations during the last glacial period north atlantic marine sediment cores show comparable variability in sea surface temperature and the deposition of ice rafted debris3 4 5 in contrast very few continental records of this time period provide the temporal resolution and environmental sensitivity necessary to reveal the extent and effects of these environmental fluctuations on the continents here we present high resolution geochemical physical and pollen data from lake sediments in italy and from a mediterranean sediment core linked by a common tephrochronology our lacustrine sequence extends to the past 102 000 years many of its features correlate well with the greenland ice core records demonstrating that the closely coupled ocean atmosphere system of the northern hemisphere during the last glacial4 extended its influence at least as far as the central mediterranean region numerous vegetation changes were rapid frequently occurring in less than 200 years showing that the terrestrial biosphere participated fully in last glacial climate variability earlier than 65 000 years ago our record shows more climate fluctuations than are apparent in the greenland ice cores together the multi proxy data from the continental and marine records reveal differences in the seasonal character of climate during successive interstadials and provide a step towards determining the underlying mechanisms of the centennial millennial scale variability

origin of the upper cretaceous tertiary sedimentary basins within the tauride anatolide platform in turkey a number of sedimentary basins formed within the tauride anatolide platform of anatolia during the late cretaceous tertiary period previous studies have proposed different tectonic and evolutionary models for each basin geological characteristics of the basins however suggest that all these basins are of the same origin and that they followed a similar evolutionary model to one another basin development within the tauride anatolide platform took place in a post collisional environment following the northward subduction of the northern neotethys ocean beneath the pontides the closure of the northern neotethys ocean ended with collision of the tauride anatolide platform with the pontide volcanic arc and resulted in large bodies of oceanic remnants thrust over the tauride anatolide platform as ophiolite nappes formation of the sedimentary basins followed the emplacement of the ophiolite nappes as they formed as piggy back basins on top of the underlying thrust ophiolite basement

a review of calcareous nannofossil astrobiochronology encompassing the past 25 million years this paper presents a review of astrobiochronological calibration of recent to late oligocene calcareous nannofossil datum events biohorizons included in the paper are those of the widely used standard nannofossil zonations of martini e 1971 standard tertiary and quaternary calcareous nannoplankton zonation in farinacci a ed proceedings of the second international conference on planktonic microfossils roma rome ed tecnosci vol 2 pp 739 785 and okada h and bukry d 1980 supplementary modification and introduction of code numbers to the low latitude coccolith biostratigraphy zonation bukry 1973 1975 marine micropaleontology 51 321 325 as well as supplementary biohorizons proposed in the literature the biohorizons have been selected on the basis of the unambiguous taxonomy of the index taxa and their biostratigraphic usefulness we emphasise the application of rigorous methodology in nannofossil studies which permits an evaluation of biohorizons in terms of reliability and calibrates their potential correlatability astrochronological age estimates rely on the geologic timescale developed by the ics in 2004 with some new calibrations included we provide an overview of the relative position of biohorizons versus the astronomically calibrated ages of magnetic reversals and reference isotope stratigraphies surprisingly there are still few high resolution quantitative biostratigraphic studies of astrochronologically tuned sections in spite of the central role of such studies in addressing fundamental problems such as the tempo and mode of plankton evolution

orbitally driven mid burdigalian coastal sabkha cycles from the sivas basin sedimentological paleontological and geochemical data abstract the early to middle miocene period in the sivas basin is represented by a thick deposition of mud dominated marine sediments karacaoren formation in an overall bay like paleogeographic setting previous studies have suggested that halokinesis induced local tectonics and orbital climatic fluctuations have been the primary controls on depositional evolution in the present study we investigated a 60 m thick karaman gypsum member kgm located at the base of the karacaoren formation in terms of its sedimentological paleontological both palynology and nannofossil biostratigraphy and geochemical mineralogical aspects to better characterize climatic controls on its deposition nannofossil assemblages indicate that the studied member is confined within the sphenolithus belemnos zone nn3 18 92 17 97 ma and is mainly composed of rhythmic alternations of supratidal evaporites and lagoonal marine mudstones the palynological data demonstrate a minor yet consistent occurrence of megathermic taxa and numerous dinoflagellate cysts in mudstone intervals the high chemical proxy of alteration cpa values and occurrence of kaolinites in the same mudstone intervals further prove deposition under warm and humid subtropical conditions the perfect match between the environmental cyclicities in the kgm with a benthic 18o curve justifies a strong control of obliquity short eccentricity of a 40 100 kyr duration and hints at radical precipitation changes throughout the individual orbital cycles these precipitation changes are explained by extreme latitudinal precipitation gradients during relatively hot periods before the mid miocene climatic optimum

weichselian palynological records from southern europe correlation and chronology abstract the high resolution independently dated palynostratigraphic record from lago grande di monticchio spanning the last 101 530 calendar years provides a basis for re evaluating the correlations between palaeoenvironmental events in europe during the last glacial as well as a means to determine their chronology the interstadial events recorded from various localities throughout europe are combined into a single scheme of correlations and a chronological framework is suggested this provides a basis for assessing the evolution of the vegetation and environmental patterns across europe during the last glacial revealing a general tendency for the latitudinal climatic gradient to have been steeper than it has been during the holocene the vegetation has also generally been subject to greater moisture deficiency either because of prevailing climatic conditions or as a reflection of the lower atmospheric concentration of co 2 the scheme of correlations is shown to be capable of being extended beyond europe not only to marine and ice core records from the north atlantic region but also to a palynological record from north west north america

mineralogical and paramorphic textural changes generated in modern ooids by heat and compaction laboratory duplication of textures previously known only from naturally occurring ooids was accomplished for the first time on heated and experimentally compacted ooids 250 c 364 kg cm 2 crystals of neomorphic calcite developed replacing aragonitic ooids in places the original fabric survived preservation of concentric laminae in ooids during this process indicates absence of an intervening stage of void formation this polymorphic transformation is a wet process and temperature dependent

late holocene vegetation dynamics on an atlantic mediterranean mountain in nw iberia abstract detailed studies on the late holocene vegetation dynamics of the mountains of nw iberia are rare furthermore the impact of human activities and changes in fire activity on the natural vegetation are not well known over these areas in order to improve the knowledge on these topics pollen and charcoal analyses were conducted on two new sedimentary sequences from the teleno mountains between ca 4500 and 3200 cal yr bp pinus type sylvestris and betula dominated the forests that covered the uplands of the teleno mountains at this point this pine birch forest was replaced with heathlands and grasslands which persisted during all the iron age and the roman period until ca 1500 cal yr bp this abrupt deforestation process could be caused by fire grazing and or mining activities linked to the exploitation of the metal resources of these mountains around 1250 cal yr bp a betula forest established in the uplands of the teleno mountains probably following a decrease in human activities the gradual rise in regional population density since ca 300 200 cal yr may be linked to the increase in fire activity that triggered the replacement of birch forest with heathlands lastly the extent of the pinus pinaster dominated forests in the lowlands is an illustrative example of how the economic activities of the local human population have controlled the vegetation cover in this area as it is very clear in the pollen record the recovery of natural p pinaster forests since ca ad 1900 associated to the start of resin exploitation

neandertal extinction and the millennial scale climatic variability of ois 3 population models seeking climate as a triggering factor for the extinction of neandertals and the colonisation of europe by anatomically modern humans are contradictory due to uncertainties in the dating methods in the cultural attribution of archaeological layers and to the lack of terrestrial continuous and well dated palaeoclimatic sequences this is particularly the case for the iberian peninsula where neandertal populations seem to have survived later than in other regions of europe a review of the available palaeoclimatic evidence for ois3 of iberia reveals that this mainly consists of low resolution fragmentary ill dated and often ill interpreted records correlation between palaeoenvironmental sequences from two images pollen rich deep sea cores and archaeological data from western europe the electronic archive of the radiocarbon dates is available at qsr website http www elsevier nl locate quascirev indicates that aurignacian moderns colonised france and the north of iberia at the onset of the h4 event during this cold episode a probable contraction of neandertal populations is recorded in southern iberia where no aurignacian settlements are detected such a decline in population density is correlated with the particular desert steppe like environments made up of artemisia chenopodiaceae and ephedra characterising the h4 of this area while reducing the size of neandertal populations this inhospitable environment may have favoured their persistence in this region mainly exploiting herds of herbivores adapted to graminees rich grasslands the aurignacian moderns were probably not interested in colonising these arid mediterranean biotopes and did that only after the h4 event

late oligocene to early miocene geochronology and paleoceanography from the subantarctic south atlantic mi2 as well as several other distinctive isotope events our data suggest that the d 18 o maximum commonly associated with the oligocene miocene o m boundary falls within c6cn 2r 23 86 ma the d 13 c maximum coincides within the temporal resolution of our record with c6cn 2n r boundary and hence to the o m boundary comparison of the stable isotope record from site 1090 to the orbitally tuned stable isotope record from odp site 929 across the o m boundary shows that variability in the two records is very similar and can be correlated at and below the o m boundary site 1090 stable isotope records also provide the first deep southern ocean end member for reconstructions of circulation patterns and late oligocene to early miocene climate change comparison to previously published records suggests that basin to basin carbon isotope gradients were small or nonexistent and are inconclusive with respect to the direction of deep water flow oxygen isotope gradients between sites suggest that the deep southern ocean was cold in comparison to the north atlantic indian and the pacific oceans dominance of cold southern component deep water at site 1090 at least until 17 ma suggests that relatively cold circumpolar climatic conditions prevailed during the late oligocene and early miocene we believe that a relatively cold southern ocean reflects unrestricted circumpolar flow through the drake passage in agreement with bathymetric reconstructions index terms 4267 oceanography general paleoceanography 1035 geochemistry geochronology 4870 oceanography biological and chemical stable isotopes keywords paleoceanography 1035 geochronology stable isotopes

the response of nw iberian vegetation to north atlantic climate oscillations during the last 65 kyr pollen and oceanographic data from deep ocean core md95 2039 provide a centennial to millennial scale record of conditions offshore and of the vegetation of north west iberia for the period 10 65 ka the planktonic oxygen isotope record of this core reflecting predominantly sea surface temperature sst shows a pattern of millennial scale oscillations that is very similar to climatic changes recorded by the greenland ice core records over the same interval in turn tree populations show a pattern of rapid expansions and contractions that follow the pronounced and abrupt isotopic shifts recorded offshore through marine isotope stage mis 3 this millennial scale pattern of vegetation change alternating between steppe and open woodland is superimposed on a longer term pattern of shrinking ericaceous heathland and decreasing size of successive interstadial tree populations trees persisted during the last glacial maximum lgm at greater abundance than during many of the coldest episodes of mis 3 this agrees with the marine data which indicate that lgm sea surface temperatures here were significantly warmer than the minima recorded in mis 3 our combined marine terrestrial record together with data from nearby sequences provides a stepping stone between terrestrial sequences and the greenland ice core and north atlantic marine records this will permit a better understanding of the behaviour of vegetation across different regions at several scales of climatic forcing

sea level changes during the pleistocene holocene in the nw coastal zone of portugal research was undertaken to establish the present coastal dynamics of the area south of espinho portugal with special emphasis on the migration inland of beaches and the retreat of cliffs during at least the last century besides the holocene units the silvalde paramos tijuca formation 2310 80 yr bp to 500 80 yr bp and the cortegaca beach formation 6850 60 yr bp to 950 80 yr bp a pleistocene unit the maceda beach formation 29 600 690 yr bp to 14300 160 yr bp with trunks of pinus sylvestris was recognized the cortegaca beach formation comprises a truncated podzol profile the al horizon dating from 3490 60 yr bp to 950 80 yr bp the study and the dating of the pleistocene and the holocene formations suggest a model of evolution related to sea level fluctuations and neotectonics during the interval between 29 000 690 yr bp and the post xvth century little ice age the final purpose of the research is to apply the results to the prediction of the coastal zone evolution and particularly to influence policy with respect to coastal zone management this policy must take into account the inland migration of the beaches and the cliff retreat as a consequence of the natural dynamics of the earth that cannot be arrested or controlled by man

paleogene calcareous nannofossil magnetobiochronology results from south atlantic dsdp site 516 abstract the detailed study of an expanded paleogene section with abundant moderate to well preserved calcareous nannofossils from south atlantic dsdp site 516 has resulted in a precise correlation of most calcareous nannofossil markers with the magnetostratigraphy many nontraditional datums have also been documented and correlated to the magnetostratigraphy comparison of the results from site 516 with those of previous studies from other areas enables a critical evaluation of the accuracy synchroneity or diachroneity of the species events over geographically long distances of special significance is the correlation for the first time of the stratigraphic ranges of chiasmolithus gigas and rhabdosphaera gladius with the magnetostratigraphy other important results include the following first occurrence fo of cruciplacolithus primus 66 3 ma fo chiasmolithus danicus 65 6 66 0 ma fo prinsius martinii 65 5 66 0 ma fo heliolithus kleinpellii 59 8 61 6 ma probably diachronous last occurrence lo of tribrachiatus orthostylus 51 0 54 8 ma unreliable fo chiasmolithus gigas 47 4 ma fo reticulofenestra umbilica 44 6 ma lo chiasmolithus gigas 44 4 46 8 ma diachronous lo nannotetrina fulgens 44 2 ma lo chiasmolithus grandis 40 0 41 6 ma probably diachronous fo chiasmolithus oamaruensis 39 8 40 4 ma unreliable fo isthmolithus recurvus 39 5 ma lo reticulofenestra reticulata 37 6 ma lo discoaster saipanensis 36 4 ma end acme of ericsonia subdisticha diachronous fo and lo sphenolithus distentus unreliable and lo reticulofenestra bisecta 24 0 ma

sedimentology petrography and diagenesis of eocene oligocene evaporites the tuzhisar formation sw sivas basin turkey abstract the study area is situated in the southwestern part of the sivas basin sediments of the ortakoy formation middle upper eocene of flysch facies were deposited in a shallow marine environment and consist of interstratified sandstone shale and calcareous mudstone the karaziyaret basaltic dikes cut the ortakoy formation the ortakoy formation is comformably overlain by the evaporite dominated tuzhisar formation gradual transitions between these two stratigraphic units crop out between yenikoy and yenituzhisar villages the tuzhisar formation is composed mainly of secondary gypsum which originated from the hydration of precursor anhydrite rock the formation has been subdivided into three members yenikoy kullu and selimiye members yenikoy lower evaporite unit and kullu upper evaporite unit members contain gypsum sequences up to 70 m thick the selimiye member lower middle oligocene which consists mainly of red clastic units interrupt and gradationally overlies laterally and vertically these two members in the gypsum of the yenikoy member nodular nodular banded laminated banded lithofacies with enterolithic and chicken wire structures are distinguished these associations indicate a sabkha or shallow water setting of deposition such as a lagoon secondary gypsum in the tuzhisar formation generally displays alabastrine and porphyroblastic textures with corroded anhydrite relics associated minerals are dolomite calcite celestite and lutecite the kullu member is composed of irregular thick bedded massive locally brecciated secondary gypsum probably formed by multiple synsedimentary collapse after the dissolution of pre existing soluble minerals and or by paleoslumping related to synsedimentary tectonism however most of the evidence for the origin of the breccia has been destroyed by intense karstification

precipitation gradients during the miocene in western and central turkey as quantified from pollen data abstract in the present paper we have analyzed thirty five palynofloras covering the time span from the early miocene aquitanian to the late miocene middle tortonian in turkey the results obtained are presented in tables and maps showing temporal palaeoprecipitation values the mean annual precipitation map exceeds 1200 mm during the aquitanian and early middle serravallian it is suggested to have been between 1000 and 1300 mm in the latest serravallian earliest tortonian in western and central turkey in the early middle tortonian the lower boundary of map decreases to below 1000 mm in central and eastern turkey today maps are represented by lower values around 600 1000 mm in western and 400 600 mm in central turkey for the driest month lmp the rainfall was not distributed homogeneously in the aquitanian the calculations are between 36 and 48 mm with humid conditions in western and eastern turkey during the burdigalian and middle miocene the driest month precipitation varied with respect to locations however it is clear that there was a reduction in precipitation during the early middle tortonian with values around 26 27 mm in central and eastern turkey the same pattern is observed for the wettest month precipitation hmp with estimates higher than 200 mm during the aquitanian and earliest tortonian although some areas received low rainfall hmp was reduced between 130 and 140 mm in the early middle tortonian the warmest month precipitation wmp varied from 96 to 140 mm except for konya ilgin kirsehir hacibektas and manisa soma that received 88 mm during the early middle miocene in the early middle tortonian the amount of summer rainfall lay between 58 and 88 mm the reason of the decrease in all rainfall parameters during the early middle tortonian could be related to several factors such as climatic cooling altitude aridification palaeotopograhy or continentality however it is necessary to indicate that the tortonian cooling had previously been proposed by akgun et al 2007 as the explanation using a large number of palynological assemblages in turkey we also observe a decrease in precipitation parameters during the middle miocene this could be related to fact that either low species diversity can result in wide coexistence intervals or the monterey cooling event was related to a cooling during the langhian and serravallian

the wurm in nw iberia a pollen record from area longa galicia the pollen record at area longa is the westernmost sequence available for investigation of the last glaciation in continental europe it is located in a region nw iberia for which data from times earlier than the late glacial period are scarce it comprises a series of exposed limnetic levels that lie above an eemian oxygen isotope stage ois 5e beach and are separated by inorganic layers the oldest limnetic level level i attributed to the early glacial period ois 5a to ois 5d shows a dominance of woodland with high proportions of fagus pollen and is tentatively identified with st germain i the lower pleniglacial ois 4 level ii records a stadial landscape of grassland and shrub level iii from the pleniglacial interstade ois 3 reflects a complex period in which three warmer woodland phases alternated with periods of more open vegetation this cyclical behavior correlates with the ice core isotope record and with the general tendencies observed in other wurmian pollen records but the composition of our pollen profiles differs from those observed in these other records in nw iberia the dominant trees were deciduous taxa not conifers of particular note is the presence of lowland fagus woodlands during the pre wurm and the occurrence of carpinus considerably farther west than the boundary of its current distribution in the iberian peninsula

an integrated field and numerical modelling study of controls on late quaternary fluvial landscape development tabernas southeast spain the variability of quaternary landforms preserved in the tabernas basin of southeast se spain raises numerous questions concerning the roles of external forcing mechanisms e g tectonics and or climate and internal landscape properties e g lithological controls in the evolution of the basin wide fluvial system over late quaternary timescales in this study we apply the fluver2 numerical model to investigate the significance of these landscape controls upon patterns of landscape evolution we highlight the complications of generating realistic input datasets for use in the modelling of long term landscape evolution e g discharge and runoff datasets model outputs are compared to extensive field mapping of fluvial terraces their sedimentary architecture and optically stimulated luminescence dating results of the terraces the results demonstrate the significance of non linear rates of flexural tectonic uplift towards the west of the tabernas basin which have controlled base levels throughout the quaternary and promoted the formation of a series of diverging fluvial terraces our numerical model results further highlight the importance of climate cycles upon river terrace formation basin wide aggradation events were modelled during the transition from marine isotope stage mis 6 to 5 and the last glacial maximum lgm as supported by field evidence this aggradational pattern supports the regional hypothesis of terrace formation during global glacial cycles and cold to warm stage transitions and supports the use of sea surface temperature climate proxy data in the modelling exercise the availability of sediments derived from the surrounding hillslopes and adjacent alluvial fans explains the generation of substantial terrace aggradations copyright 2015 john wiley sons ltd

miocene precipitation in europe temporal trends and spatial gradients article i nfo it is known from present day climates that both temporal and spatial variations in precipitation can be more pronounced than those in temperature and thus influence ecosystems and human society in more substantial way however very little is known about such variations in the past here we present an analysis of 206 palaeoprecipitation data from two twelve million year long proxy records of precipitation for southwest calatayud teruel basin and central europe western and central paratethys spanning the late early and middle to late miocene 17 8 5 3 ma at a temporal resolution of about 80 kyr and 200 kyr respectively the estimates of precipitation are based on the ecophysiological structure of herpetological assemblages the results show that precipitation variations in both regions have large amplitudes during the miocene with comparable temporal trends at longer time scales with locally 300 mm up to more than 1000 mm more rainfall per year than present the early langhian and the tortonian were relatively wet periods whereas the late langhian and late serravallian were relatively dry with up to 300 to 500 mm less precipitation than present the most humid time intervals were the early and middle tortonian washhouse climate periods overall our data suggest that the latitudinal precipitation gradient in europe from the middle to late miocene were highly variable with a general tendency towards a reduced gradient relative to present day values the gradient decreases during cooling periods and increases during warming periods similar to results from simulations of future climate change interestingly the precipitation gradient was reversed during the second washhouse climate period and the early messinian which may have causes a negative hydrologic balance in the eastern paratethys during the latter time yet our reconstructed gradient curve shows no direct correlation with the global temperature signal from oxygen isotopes which implies a non linear regional response our results further suggest that major fluctuations in the precipitation gradient can be responsible for shifts in ecosystem distribution and particularly for faunal turnover in south western europe

the climate and landscape of the middle part of the weichselian glaciation in europe the stage 3 project abstract oxygen isotope stage 3 ois 3 was a mild interval between the two cold maxima of the last weichselian glaciation marked by climate changes oscillating on a 100 1000 yr time scale between near interglacial and peak glacial conditions during ois 3 modern humans entered europe and somewhat later their neanderthal predecessors became extinct our understanding of this momentous event depends on an answer to the question did the unstable environmental conditions of the time play a significant role in early human history the stage 3 project is an interdisciplinary study with two main goals 1 to describe with existing data and to simulate the climates and landscapes of typical warm and cold phases between 45 000 and 30 000 yr ago and 2 to compare the results with the spatial and temporal distribution of human beings in this context this paper introduces the stage 3 project and provides background to a set of papers on the climate and landscape aspects of the project that will appear in quaternary research and to studies of their relevance to the early upper paleolithic of europe to appear in journals yet to be determined

calcareous nannofossils in extreme environments the messinian salinity crisis polemi basin cyprus the rapidly changing and extreme environmental conditions of the early messinian salinity crisis are reflected in abrupt variations in nannofossil assemblages within the messinian units kalavasos formation from the polemi basin during the messinian sedimentary and microfossil data indicate that the polemi basin was a semi enclosed shallow water basin subject to repeated influxes of marine and freshwater this is supported by the absence of many open marine nannoplankton e g discoaster and by the presence of neritic littoral and freshwater diatoms whilst calcareous nannoplankton are known to occupy near shore habitats they are rarely preserved in such environments due to terrigenous and clastic influx the shallow and eutrophic environments of the messinian polemi basin therefore provide an unusual opportunity to investigate which extinct nannofossil taxa occupied marginal marine environments nannoplankton diversity 3 to 11 species is low in comparison to the open ocean and the assemblages are extremely uneven with high dominance one of five species reticulofenestra minuta reticulofenestra antarctica helicosphaera carteri umbilicosphaera jafari and sphenolithus abies was observed to dominate in all of the assemblages these were broadly distributed marine species but capable of opportunistic behaviour salinity and nutrient levels are thought to be the primary factors controlling the overall nature of the nannoplankton assemblages using the associated diatom and sedimentological evidence we infer the palaeoecology of key nannofossil taxa and speculate on the palaeoenvironments of the messinian polemi basin r antarctica is thought to have dominated in normal salinity mesotrophic shallow water environments h carteri in shallow brackish eutrophic environments u jafari in hypersaline conditions r minuta in eutrophic conditions with an abnormal salinity from brackish to hypersaline and s abies in mesotrophic deeper and normal salinity environments d 2005 elsevier b v all rights reserved

the biogeographical role of pinus forest on the northern spanish meseta a new holocene sequence abstract the aim of this paper is to reconstruct the variation in the vegetation during the holocene on the northern meseta through pollen analysis in order to determine the roles played by pinus and quercus in the vegetation dynamics a new pollen sequence camporredondo in the centre of the duero river basin northern meseta spain is presented it covers the period from ca 11 250 to 1630 cal yr bp the camporredondo sequence suggests that a forested landscape existed from the start of the holocene with values of approximately 90 of arboreal pollen mainly derived from pine forests in the surroundings shortly after 8600 cal yr bp pine forests continued to dominate but the landscape became more open while stands of deciduous and evergreen quercus developed around 4500 years ago coinciding with the start of a period of less rainfall the lacustrine areas in these territories began to silt up favouring hydrophytic taxa such as salix or cyperaceae a comparison with other holocene pollen sequences from the central eastern part of the northern meseta confirms the presence of pine forests in the whole region since the early holocene we discuss the variations of the general vegetation pattern in terms of the local or regional conditions at each site throughout the holocene pinus forests dominated at least in the eastern half of the duero river basin the typical holocene substitution of conifers by broadleaf species as recorded in other parts of the iberian peninsula and europe never takes place in the study area the results of the present study suggest that the current view of the potential vegetation in the spanish northern meseta should be reviewed

vegetation and environmental conditions in the donana natural park coastal area sw iberia at the beginning of the last glacial cycle detailed reconstructions of the vegetation of iberia during the last glacial inception are rare due to the limited number of terrestrial sites recording this period active retreat of el asperillo cliff located on the atlantic coast of southwestern iberia has exposed a fossil organic level dating back to one of the early stades of the last glacial cycle pollen and macrofossil analyses from this site show that the donana area was covered mainly by steppic vegetation temperate trees survived the coldest periods albeit in reduced numbers mediterranean taxa are extremely reduced in contrast with other dry areas of southern iberia over this time span this vegetation suggests cold and arid climatic conditions in accordance with paleoclimatic reconstructions based on several atlantic marine cores

deep burial diagenesis its implications for vertical movements of the crust uplift of the lithosphere and isostatic unroofing a review abstract various techniques of study of strata exposed at the surface in undeformed areas of the appalachian basin and ozark done imply that these strata have been heated to temperatures that suggest a former great depth of burial the data reveal that the strata have been much more deeply buried than previously thought if such former deep burial has taken place then subsequent uplift and erosion must also have taken place to bring these formerly deeply buried strata to the present land surface unexpectedly large amounts of uplift and erosion ranging from 4 3 to 7 km have re exposed these formerly deeply buried rocks this leads to the surprising conclusion that isostatic unroofing has stripped off thick sections of strata whose presence was previously unsuspected therefore the lithosphere in its isostatic unroofing of thick sequences of sedimentary strata has undergone much larger vertical motions than many geologists had previously estimated case histories in this review include strata of the silurian of the northern appalachian basin and of the ordovician of the ozark dome which reached interpreted maximum burial depths of 5 and 4 3 km respectively devonian strata in the catskill mountains of new york imply a former depth of burial of 6 5 km lower ordovician carbonate sequences of the northern appalachian basin imply a depth of burial in excess of 7 km middle ordovician strata from the same basin signify a depth of burial of approximately 5 km and devonian strata a paleodepth of 4 5 5 km such former great depths of burial of undeformed strata which are now exposed at the surface reflect large scale vertical movements of the crust and uplift of the lithosphere these drastic changes represent isostatic unroofing with widespread implications for paleogeography of a kind unrecognized at present

alpine evidence for atmospheric circulation patterns in europe during the last glacial maximum the configuration of alpine accumulation areas during the last glacial maximum lgm has been reconstructed using glacial geological mapping the results indicate that the lgm ice surface consisted of at least three major ice domes all located south of the principal weather divide of the alps this implies that the buildup of the main alpine ice cover during oxygen isotope stage ois 2 was related to precipitation by dominant southerly atmospheric circulation in contrast to today s prevalent westerly airflow such a reorganization of the atmospheric circulation is consistent with a southward displacement of the oceanic polar front in the north atlantic and of the associated storm track to the south of the alps these results combined with additional paleoclimate records from western and southern europe allow an interpretation of the asynchronous evolution of the different european ice caps during the last glaciation 18o stages ois 4 and 3 were characterized by location of the polar front north of 46 n gulf of biscay this affected prevailing westerly circulation and thus ice buildup in western scandinavia the pyrenees vosges and northern alps at the lgm however the polar front lay at 44 n causing dominating southerly circulation and reduced precipitation in central and northern europe

early miocene climate and biomes of turkey evidence from leaf fossils dispersed pollen and petrified wood abstract the early miocene was a period of major palaeogeographic reorganization in the eastern mediterranean region during which time the anatolian plateau became subaerial and several intracontinental basins intermittently became connected to the paratethys and mediterranean seas in this paper we analyse early miocene vegetation and climate using leaf records palynological assemblages and fossil wood at 36 localities from western and central turkey most of which have precise age control based on radiometric dating and mammal faunal ages using the leaf flora of guvem bes konak kesekoy climate leaf analysis multivariate program clamp analyses and koppen signatures were employed to infer a palaeoclimate typical of modern laurel forest regions based on the palynological records abundance of various pollen taxa was used as a measure of openness of vegetation and regional presence of major tree taxa most pollen floras are dominated by tree pollen ranging from 85 to 98 and indicated widespread afforestation in the pollen diagrams shifts in dominance from swamp forest elements taxodioideae to well drained forests pinaceae indicate changes in lake levels or phases of basin development such shifts may have been associated with the development of more xeric forest vegetation wood anatomical features such as false tree rings further may indicate seasonal climate pollen diagrams and macrofossils reflect zonal and azonal broadleaf and needleleaf forest and extrazonal open vegetation the latter occurred in areas with shallow soils on volcanic rocks or limestone e g cycads dracaena or coastal areas herb dominance taxonomic composition and biogeographic affinities suggest laurel forest as a major forest biome on well drained soils and ecotones between laurel forest and broadleaf deciduous forest biomes a comparison with younger floras shows that these are neither more diverse nor more warmth loving despite an increase in global temperature mid miocene climatic optimum suggesting bottlenecks during previous oligocene cooler times for warmth loving taxa

fluvial evaporitic and shallow marine facies architecture depositional evolution and cyclicity in the sivas basin lower to middle miocene central turkey abstract lower to middle miocene rocks in the karayun region of the sivas basin are represented by the agilkaya and egribucak formations forming a 4 km thick continuous section each formation is subdivided into three members representing similar lithofacies the lower members are made up of fluvial sheet sandstone and red mudstone that migrated laterally on a flood basin within a semi arid fan system the middle members are composed of bedded to massive gypsum and red green mudstone of a coastal and or continental sabkha environment they are intercalated with lagoonal dolomitic limestone and bituminous shale in the agilkaya formation and fluvial red pink sandstone red mudstone in the egribucak formation the upper members are made up of shallow marine fossiliferous mudstone and sandy limestone rapid vertical and horizontal facies changes in both formations reflect the locally subsiding nature of this molassic basin the overall section can be also subdivided into three orders of fining upward cycles type i cycles correspond to the agilkaya and egribucak formations each around 2 km thick and indicate two long term transgressive phases controlled by tectono eustatic factors type ii cycles 140 m thick on average are formed by alternations of fluvial sheet sandstone and red mudstone capped by up to 50 m thick red flood basin mudstone a 400 ka period milankovitch cyclicity related to astronomical climatic fluctuations is suggested as a governing mechanism although subsidence cannot be excluded the existence of laterally persistent fluvial sheet sandstone overlain by red mudstone that forms fining upward type iii cycles 10 m thick on average is attributed to changes in subsidence rate rhythmic alternations between gypsum beds and red green mudstone and or dolomitic limestone and bituminous shale observed in the middle members might be related to minor periodical climatic changes rather than to tectonics

high resolution palynological record off the iberian margin direct land sea correlation for the last interglacial complex abstract we present high resolution pollen dinocyst and isotopic data for the last interglacial complex from marine core md952042 southwestern margin of the iberian peninsula 37 48 n 10 10 w 3148 m direct land sea correlation from this core indicates that during this period north atlantic sea surface temperatures were in phase with iberian climate our palynological analysis suggests a younger dryas like event at the marine isotope stage mis 6 5 transition the analysis also indicates that the eemian spans from the lightest isotopic values of mis 5e ca 126 ky bp to the heavier isotopic values towards the mis 5e 5d transition therefore the eemian is not entirely equivalent to mis 5e pollen analysis identifies four climatic phases of low amplitude during the eemian a mediterranean climate in southwestern europe is gradually replaced by oceanic conditions the middle of the eemian is characterized by an increase in precipitation on the land and ocean associated with a slight cooling this seems to be the result of a displacement of the polar front as far south as southern europe during this period after the eemian three relatively short climatic phases on land melisey i st germain ia and montaigu cold event occurred contemporaneously with three shifts of sea surface temperatures the montaigu event first identified in terrestrial pollen sequences is therefore also recorded in core md952042 on the basis of pollen dinocyst and planktonic isotopic data our results also show that the warm periods of mis 5 are not characterized by similar climatic conditions on land

controls and evolution of fan delta systems in the miocene pohang basin se korea abstract the miocene pohang basin southeastern korea occurs in the eastern part of the ne sw trending yangsan fault which has experienced right lateral strike slip deformation since the eocene during the miocene however the strike slip movement was negligible and instead was under extensional regime large scale drainage systems were developed at the junction between the strike slip zone and the oblique transfer faults acting as major sources for coarse grained sediments high rate of sediment supply and rapid subsidence of the hanging wall resulted in the progradation of large scale gilbert type fan deltas doumsan duksung and gohyun systems which all show a radial distributional pattern along the steeply inclined footwall scarps created by ne sw trending faults the drainage systems were relatively small here low rate of sediment supply formed scree apron type malgol and yugye systems and steep faced slope type maesan system fan deltas based on variations in sedimentary facies and distribution architecture and overlapping patterns the fan delta systems in the pohang basin can be divided into four stages of evolution during the early stage early miocene alluvial fans prograded into shallow marine setting in the doumsan and duksung systems high rate of sediment supply and rapid rise of relative sea level resulted in the transformation of shoal water type to gilbert type foresets in the malgol and maesan systems rapid sea level rise accompanied with low rate of sediment supply caused transformation of alluvial fans to scree apron type and steep faced slope type fan deltas respectively in the second stage subsidence of the hanging wall formed large scale truncation surfaces in the doumsan and duksung fan deltas coarse grained sediments were continuously supplied in the doumsan system whereas only fine grained sediments were deposited in the duksung system in the malgol system sediment supply was almost terminated in this stage in the third stage middle miocene sediment supply rate of the doumsan fan delta decreased abruptly and the system was overlain by fine grained gilbert type deposits the duksung fan delta was overlain by the maesan and gohyun systems the maesan system prograded further basinward during the last stage late miocene sediment supply of the doumsan and maesan systems was also terminated and the entire basin was draped by fine grained biogenic materials mainly diatoms

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

first high resolution multi proxy palaeoenvironmental record of the late glacial to early holocene transition in the ria de arousa atlantic margin of nw iberia abstract a 322 cm long sedimentary sequence obtained in the shallow marine basin of the ria de arousa a submerged unglaciated river valley on the atlantic margin of northwestern iberia was analysed using a multi proxy approach to study how climatic and sea level changes affected the coastal ecosystems during the last glacial interglacial transition past sedimentation vegetation and marine productivities were inferred from palynological radiocarbon seismic and lithological data a substantial reduction in the pollen and dinoflagellate cyst accumulation rates is observed at 12 700 to 11 700 cal a bp suggesting lower marine and vegetation productivities likely as a response to the younger dryas cooling event overall the regional vegetation changed from cold tolerant open woodlands pinus sylvestris p nigra and betula dominating before 10 200 cal a bp to coastal wetlands and the regional spread of quercus dominated forests after 9800 cal a bp cluster analysis and principal component analysis allowed the identification of several small environmental oscillations such as the 11 4 ka and 10 5 ka cooling events after that a conspicuous heath expansion was likely favoured by the palaeotopography the increased precipitation and the relative sea level rise which might have caused a profound change in the coastal configuration concurrently both the dinoflagellate cyst and non pollen palynomorph records reveal variations in the marine productivity and coastal hydrodynamics that also agree with a period of marked marine transgression warming and increasing river flow new sedimentary data highlight the high sensitivity of the ria s ecosystems to environmental oscillations and show a close temporal correspondence between terrestrial and marine responses to climate change

a lower pleistocene to holocene terrestrial record from the eskisehir graben central anatolia paleoclimatic and morphotectonic implications abstract as one of the rare terrestrial archive with continuous sedimentation back to almost 1 ma in anatolia the eskisehir graben was investigated in outcrops and cores by multi proxy analysis regarding chronology and paleoclimatology the present study comprises significant implications for both the impact of climate changes on fluvial systems in the timescales of the milankovitch band and the controversial age and rate of the crustal extension in western anatolia our findings indicate that loi950 and 18ocarb which are indicators for the amount of soil carbonate and paleo temperature respectively are collectively capable of distinguishing between glacial and interglacial periods in the predominantly floodplain deposits of the graben infill secondarily loi550 and 13ccarb values further help this discrimination via primary production and composition of vegetation cover respectively pollen data albeit highly discontinuous due to poor preservation under subaerial conditions point out a steppe like vegetation cover where the forest components expand particularly in the wet interglacial periods in the other hand the chronological frame provided by astronomical calibration of certain proxy records strongly suggest that the eskisehir fault zone initiated as a boundary fault of a half graben some 900 ka the rate of vertical movement on its southern branch since the last 70 ka is unexpectedly high 2 3 mm a a phenomenon that requires urgent risk assessment analysis in the vicinity of the eskisehir city

european vegetation during marine oxygen isotope stage 3 european vegetation during representative warm and cold intervals of stage 3 was inferred from pollen analytical data the inferred vegetation differs in character and spatial pattern from that of both fully glacial and fully interglacial conditions and exhibits contrasts between warm and cold intervals consistent with other evidence for stage 3 palaeoenvironmental fluctuations european vegetation thus appears to have been an integral component of millennial environmental fluctuations during stage 3 vegetation responded to this scale of environmental change and through feedback mechanisms may have had effects upon the environment the pollen inferred vegetation was compared with vegetation simulated using the biome 3 5 vegetation model for climatic conditions simulated using a regional climate model regcm2 nested within a coupled global climate and vegetation model genesis biome despite some discrepancies in detail both approaches capture the principal features of the present vegetation of europe the simulated vegetation for stage 3 differs markedly from that inferred from pollen analytical data implying substantial discrepancy between the simulated climate and that actually prevailing sensitivity analyses indicate that the simulated climate is too warm and probably has too short a winter season these discrepancies may reflect incorrect specification of sea surface temperature or sea ice conditions and may be exacerbated by vegetation climate feedback in the coupled global model

redistribution and geochemical behaviour of redox sensitive elements around s1 the most recent eastern mediterranean sapropel the youngest eastern mediterranean sapropel s1 is generally believed to have formed 7 9 14c ky b p the distribution of redox sensitive elements above in and below the sharply defined organic rich unit reveal that s 1 has already suffered heavy diagenetic alteration its present thickness based on its dark colour is only a fraction of its original thickness in one core visual evidence of s1 with an inferred initial thickness of 6 cm has been destroyed and a similar thickness appears to have been lost from the tops of another two examples this is caused by oxidation of the upper reaches of s 1 by a progressive oxidation front which commenced 5 2 5 4 14c ky ago and still appears to be active in the three cores studied diagenetic relocation of many redox sensitive elements has occurred most elements expected to be enriched in sapropels or sulphide rich sediments already have maximum concentrations above or below rather than in the present s 1 layers similarities are observed in the geochemical behaviour of as fe and p of co cu mn ni and zn and of cd mo sb ti u and v the behaviour of ba is distinctive and its immobility as barite makes it an indicator for palaeoproductivity and the original high s1 corg content the elements se and i exhibit particularly large sharp concentration peaks and together are proposed as useful indicators of the present boundary between oxic and post oxic conditions

palynostratigraphy of the last interglacial glacial cycle in germany abstract the last interglacial glacial cycle comprises the eemian and the weichselian in the area of the scandinavian glaciation respectively the riss wurm and the wurm in southern germany drastic changes of the vegetation have occurred several times during this period in europe the best known in germany is the development of the forests of the last interglacial stage and of the two succeeding early glacial interstadial phases the brorup and the odderade above the odderade sediments of two more middle weichselian interstadials the oerel and the glinde with a shrub tundra vegetation have been found at one site in northern germany in southern germany the palynological record ends somewhat earlier i e with the equivalent of the oerel interstadial which here in the south had a forest vegetation numerous single occurrences of interstadial sediments of different age and vegetation have been studied but unfortunately their stratigraphic position is most frequently unclear therefore a general survey can only rely on few but long sequences their comparison shows that vegetational gradients of different steepness existed at different times which mirror the changing climatic gradients of this period the main points of the vegetational zonation as far as it is known from germany for the cycle are summarized

evidence for general instability of past climate from a 250 kyr ice core record recent results1 2 from two ice cores drilled in central greenland have revealed large abrupt climate changes of at least regional extent during the late stages of the last glaciation suggesting that climate in the north atlantic region is able to reorganize itself rapidly perhaps even within a few decades here we present a detailed stable isotope record for the full length of the greenland ice core project summit ice core extending over the past 250 kyr according to a calculated timescale we find that climate instability was not confined to the last glaciation but appears also to have been marked during the last interglacial as explored more fully in a companion paper3 and during the previous saale holstein glacial cycle this is in contrast with the extreme stability of the holocene suggesting that recent climate stability may be the exception rather than the rule the last interglacial seems to have lasted longer than is implied by the deep sea specmap record4 in agreement with other land based observations5 6 we suggest that climate instability in the early part of the last interglacial may have delayed the melting of the saalean ice sheets in america and eurasia perhaps accounting for this discrepancy

holocene coastal carbonates and evaporites of the southern arabian gulf and their ancient analogues abstract the holocene sediments of the coast of the united arab emirates in the southeastern arabian gulf are frequently cited in the literature as type examples for analogous assemblages of carbonates evaporites and siliciclastics throughout the geologic record this paper is intended as a convenient single source for the description of sediments of this region providing information on how to reach the classic localities and some of the analogs the holocene sediments of the region accumulate over an area that is 500 km long and up to 60 km wide the sediments collecting offshore are predominantly pelecypod sands mixed with lime and argillaceous mud with these latter fine sediments increasing as the water deepens the pelecypod rich sediments also collect east of abu dhabi island both in the deeper tidal channels between the barrier island lagoons and in deeper portions of the protected lagoons west of abu dhabi island the shallow water margin is the site of coral reefs and coralgal sands whereas to the east oolites accumulate on the tidal deltas of channels located between barrier islands grapestones accumulate to the lee of the reefs and the oolite shoals where cementation becomes more common they are particularly common on the less protected shallow water margins of the lagoons west of abu dhabi island pelleted lime muds accumulate in the lagoons in the lee of the barrier islands of the eastern abu dhabi lining the inner shores of the protected lagoons of abu dhabi and on other islands to the west are cyano bacterial mats and mangrove swamps landward of these a prograding north facing shoreline is formed by supratidal salt flats sabkhas in which evaporite minerals are accumulating this paper describes the localities associated with 1 the mangrove swamps of the west side of the al dhabaiya peninsula 2 the indurated cemented carbonate crusts cyanobacterial flats and sabkha evaporites on the shore of the khor al bazam south of qanatir island 3 the reef and oolitic sand flats on the coast just east of jebel dhana and 4 the marine travertine and aragonite coats associated with the beach sediments in a small bay south of jebel dhana and 5 the sabkha mutti between jebel barakah and al sila similar sedimentological associations of carbonate and evaporites to those of the holocene of the united arab emirates are to be found in the tertiary and mesozoic sedimentary rocks of the immediate subsurface in the arabian gulf other analogs to this setting include the paleozoic carbonates of the western usa europe and asia mesozoic carbonates of the gulf of mexico europe and middle east and tertiary sedimentary rocks in the middle east

evidence for massive discharges of icebergs into the north atlantic ocean during the last glacial period sediments in the north atlantic ocean contain a series of layers that are rich in ice rafted debris and unusually poor in foraminifera1 here we present evidence that the most recent six of these heinrich layers deposited between 14 000 and 70 000 years ago record marked decreases in sea surface temperature and salinity decreases in the flux of planktonic foraminifera to the sediments and short lived massive discharges of icebergs originating in eastern canada the path of the icebergs clearly marked by the presence of ice rafted detrital carbonate can be traced for more than 3 000 km a remarkable distance attesting to extreme cooling of surface waters and enormous amounts of drifting ice the cause of these extreme events is puzzling they may reflect repeated rapid advances of the laurentide ice sheet perhaps associated with reductions in air temperatures yet temperature records from greenland ice cores appear to exhibit only a weak corresponding signal moreover the 5 10 000 yr intervals between the events are inconsistent with milankovitch orbital periodicities raising the question of what the ultimate cause of the postulated cooling may have been

characteristic features and structural evolution of a post collisional basin the sivas basin central anatolia turkey abstract the ene ssw trending sivas basin is located at the easternmost wedge like tip of the central anatolian block and exhibits characteristics of two other basins one in west central anatolia and the other in eastern anatolia the sivas basin started to form within a collisional mosaic during maastrichtian time with the pre maastrichtian basement the latter composed of continental metamorphic rocks jurassic lower cretaceous platform carbonates of the tauride belt and ophiolites and ophiolitic melange derived from closure of the northern branch of neo tethys similar tertiary basins were developed on comparable collisional mosaics in other parts of anatolia the sivas basin is asymmetrical in both the longitudinal and transversal directions its infill is dominated by a thick maastrichtian tertiary shallow marine continental succession resting unconformably on pre maastrichtian basement rocks and dissected into several subbasins this infill consists of post collisional deposits which overlie paleotectonic units unconformably and each subbasin is bounded by northeast southwest trending oblique slip faults exhibiting dominant strike slip the subbasins are characterized by contrasting stratigraphic successions although all are composed of interstratified continental and shallow marine facies both the northern and southern margins of the subbasins include upper eocene olistostromes containing mega blocks of varied origin the latter are sourced in paleotectonic units and were reworked in a shallow marine depositional setting the fill of the middle subbasins exhibits strong vertical and lateral facies changes characterized by local and regional unconformities and includes continental to shallow marine volcanic rocks this basin was deformed under north south directed compression during late pliocene quaternary times during the neotectonic phase of deformation this deformation divided the basin into new small scale mainly pull apart subbasins including those at imranli ishani altinyayla and arkisla from stratigraphic and structural correlations a post collisional intra continental basin model for the sivas basin is preferred

comparison of sequences formed in marine sabkha subaerial and salina subaqueous settings modern and ancient marine evaporites occurring in modern subaqueous salina settings and subaerial sabkha settings are different subaqueous holocene evaporites occur as shoaling upward lacustrine sequences up to 10 m thick they are evaporite dominated and are composed primarily of bottom nucleated crystals that may be deposited as massive laminated or rippled units each coastal lake is dominated by laminated evaporites with subordinate carbonate sediments in plan view they show a well developed bull s eye pattern with a sulfate center and a carbonate rim in contrast subaerial sabkha evaporites occur as part of a laterally prograding shoaling upward peritidal sequence in which the supratidal unit is usually no more than 1 m thick sabkha sequences are matrix dominated not ev porite dominated with the bulk of the sulfate phase occurring as diagenetic nodules enteroliths or diapirlike structures these sulfates were formed during syndepositional diagenesis by replacement and displacement processes the various facies of the sequence tend to accumulate in belts parallel with the shoreline relative to the sea level or the brine level sabkhas tend to form over paleotopographic highs whereas salinas tend to occur in paleotopographic lows some of the characteristics that distinguish holocene subaerial and subaqueous evaporite sequences can be used to do the same for similar ancient facies even when gypsum has been converted to nodular anhydrite the distinction is important for it can be used by explorationists in the oil industry to define the paleotopography of the associated underlying porous and nonporous carbonates

paleomagnetic correlations between scandinavian ice sheet fluctuations and greenland dansgaard oeschger events 45 000 25 000 yr b p abstract two paleomagnetic excursions the skjong correlated with the laschamp about 41 000 gisp2 yr b p and the valderhaug correlated with the mono lake about 34 000 gisp2 yr b p have been identified in stratigraphic superposition in laminated clay deposited in ice dammed lakes in three large caves in western norway during both periods the margin of the scandinavian ice sheet advanced and reached the continental shelf beyond the outermost coastline the mild 4000 yr long alesund interstade when the coast and probably much of the hinterland were ice free separated the two glacial advances the two paleomagnetic excursions have also been indirectly identified as increased fluxes of 36cl and 10be in the grip ice core greenland this article presents a correlation between ice margin fluctuations of the scandinavian ice sheet and the stratigraphy of grip gisp cores using the paleomagnetic excursions and the 36cl and 10be peaks and thus circumventing the application of different dates or time scales some of the fluctuations of the scandinavian ice sheet were of the allerod younger dryas type in the sense that its margin retreated during mild interstades on greenland and readvanced during cold stades however some fluctuations were apparently not in phase with the greenland climate

detrital input productivity fluctuations and water mass circulation in the westernmost mediterranean sea since the last glacial maximum 1 by presenting sea surface temperatures planktonic oxygen isotope profiles and bulk geochemical composition of core sediments we offer a multiparameter reconstruction of western mediterranean oceanography from the last glacial maximum until the middle holocene 20 000 5000 cal years b p sediments from ocean drilling program site 975 in the algero balearic basin have been compared with three alboran basin cores ttr 300g ttr 302g and ttr 304g all of them investigated at high resolution this multiproxy approach has allowed two different modes of circulation to be recognized 1 during the lgm and from 8 0 cal ka b p onward no surface gradient in 18og bulloides is found associated with low productivity in close analogy to modern conditions 2 during the bolling allerod and early holocene significant surface isotopic gradients are found with periods probably indicating an unstable water column associated with enhanced productivity and low bottom oxygen conditions the close synchrony between the occurrence of the surface isotopic offset and organic rich layer formation implicates that the origin of these features is linked probably via shoaling of the regional thermohaline circulation paleo ssts derived from planktonic foraminifer assemblages indicate abrupt changes in surface conditions during the analyzed time interval fluctuations in marine productivity based on ba and total organic carbon are related to water column stability and atmospheric conditions a sharp warming and 18og bulloides excursion at the end of the younger dryas is probably linked to glacial meltwater influence the riverine input has been reconstructed using the mg al ratio and mg al peaks during arid periods greenland stadial 2a and younger dryas related to bypass margin processes

european climatic response to millennial scale changes in the atmosphere ocean system during the last glacial period abstract pollen foraminifer dinocyst and coarse lithic high resolution analyses and 18 o measurements have been carried out for the last glacial section of marine core md95 2042 located near the southwestern margin of the iberian peninsula the pollen data indicate a high frequency of vegetational changes on the adjacent continent during this period suggesting a climatic variability very similar to that of the dansgaard oeschger cycles recorded by the greenland ice cores the detailed direct correlation of the terrestrial and marine proxy data from core md95 2042 indicates a three phase pattern of heinrich events in land and ocean environments the first and last phases of the h5 and h4 events are characterized by a mild and humid climate in southwestern europe probably associated with the european origin of the ice rafted detritus the middle phase exhibits a cold and dry climate in iberia linked with the maximum input of ice rafted detritus this phase seems to correspond with the laurentide ice sheet surges between the heinrich events several cold and dry periods on land are correlated with stades of the dansgaard oeschger cycles the impact of the dansgaard oeschger stades in southwestern europe seems to be preferentially connected to the cold winter air masses reaching this mid latitude region

astronomic calibration of the late oligocene through early miocene geomagnetic polarity time scale at ocean drilling program odp site 1090 subantarctic south atlantic benthic foraminiferal stable isotope data from cibicidoides and oridorsalis span the late oligocene through early miocene f24 16 ma at a temporal resolution of f5 ky over the same interval a magnetic polarity stratigraphy can be unequivocally correlated to the geomagnetic polarity time scale gpts thereby providing direct correlation of the isotope record to the gpts in an initial age model we use the newly derived age of the oligocene miocene o m boundary of 23 0 ma of shackleton et al geology 28 2000 447 revised to the new astronomical calculation la2003 of laskar et al icarus in press to recalculate the spline ages of cande and kent j geophys res 100 1995 6093 we then tune the site 1090 y 18 o record to obliquity using la2003 in this manner we are able to refine the ages of polarity chrons c7n through c5cn 1n the new age model is consistent within one obliquity cycle with previously tuned ages for polarity chrons c7n through c6bn from shackleton et al geology 28 447 450 2000 when rescaled to la2003 the results from site 1090 provide independent evidence for the revised age of the oligocene miocene boundary of 23 0 ma for early miocene polarity chrons c6aar through c5cn our obliquity scale age model is the first to allow a direct calibration to the gpts the new ages are generally within one obliquity cycle of those obtained by rescaling the cande and kent j geophys res 100 1995 6093 interpolation using the new age of the o m boundary 23 0 ma and the