late paleozoic mesozoic tectonics of the dinarides revisited implications from 40ar 39ar dating of detrital white micas detrital white mica has been dated by the single grain 40 ar 39 ar technique from three distinct stratigraphic levels and tectonic settings within the dinarides in order to monitor the geodynamic evolution of this segment of alpine orogen which is located near the transition of variscan to pan african continental crust detrital micas of a pennsylvanian foreland basin suggest erosion of medium to deep crustal levels of the variscan orogen the 40 ar 39 ar ages indicate almost no preservation of older pre variscan crust except for a low proportion of late pan african ages these data are in accordance with previous findings from the variscan belt that suggest that the whole upper level of variscan crust had been nearly entirely eroded prior to molasse deposition variscan micas also dominate in graywackes of the middle to late jurassic trench filling deposits exposed within the dinaric ophiolite belt indicating a nearby variscan continent no mica from a mesozoic metamorphic accretionary complex has been detected by contrast the upper cretaceous vardar flysch postdates the emplacement of the dinaric ophiolite belt as part of the dinaric carpathian metamorphic orogenic wedge and likely represents a collapse basin postdating early to early late cretaceous nappe stacking the studied micas comprise a dominant variscan group and a subordinate early cretaceous group from the eroding metamorphic orogenic wedge

dinoflagellate cyst assemblages as tracers of sea surface conditions in the northern north atlantic arctic and sub arctic seas the new n 677 data base and its application for quantitative palaeoceanographic reconstruction the distribution of dinoflagellate cyst dinocyst assemblages in surface sediment samples from 677 sites of the northern north atlantic arctic and sub arctic seas is discussed with emphasis on the relationships with sea surface parameters including sea ice cover salinity and temperature of the coldest and warmest months difficulties in developing a circum arctic data base include the morphological variation within taxa e g operculodinium centrocarpum islandinium cezare and polykrikos sp which probably relate to phenotypic adaptations to cold and or low salinity environments sparse hydrographical data together with large interannual variations of temperature and salinity in surface waters of arctic seas constitute additional limitations nevertheless the use of the best analogue technique with this new dinocyst data base including 677 samples permits quantitative reconstruction of sea surface conditions at the scale of the northern north atlantic and the arctic domain the error of prediction calculated from modern assemblages is 1 3 ca nd 1 8 c for the temperature of february and august respectively 1 8 for the salinity and 1 5 months yr 1 for the sea ice cover application to late quaternary sequences from the western and eastern subpolar north atlantic labrador sea and barents sea provide reconstructions compatible with those obtained using the previous dinocyst data base n 371 which mainly included modern data from the northern north atlantic copyright 2001 john wiley sons ltd journal of quaternary science

eemian early weichselian n s temperature gradients north atlantic nw europe abstract based on benthic marine organisms and or vegetation development at coastal sites in the eastern atlantic region temperature profiles of the last interglacial stage 5e and the early weichselian interstadial odderade stage 5a have been constructed from 40 to 80 degrees north the shape of the eemian summer temperature profile is very similar to the present but at all sites the eemian temperatures are a few degrees c warmer than present the odderade temperature conditions are very similar to the present both in the north on svalbard and in the south the nederlands france however in norway denmark and nw germany the odderade climate is much cooler than today sea surface temperature sst estimates inferred from planktonic foraminifera from the norwegian sea and the north atlantic show the same temperature trends as those inferred from the coastal sections these observations confirm the close relationship between western european climate and north atlantic surface conditions based on comparison between these temperature trends and insolation data we suggest that the development to an interstadial or interglacial type of climate in w europe is controlled by orbital forcing furthermore these results stress that quaternary stratigraphers working at high and low latitudes should be especially careful when using climatic inferences as a basis for correlation to interglacials or interstadials

last interglacial eemian hydrographic conditions in the southeastern baltic sea ne europe based on dinoflagellate cysts abstract a rich organic walled dinoflagellate cyst and pollen record from the licze borehole in northern poland has been used to reconstruct the hydrographic history of the southeastern baltic sea during the last interglacial eemian stage late pleistocene warm saline waters ca 10 15 psu entered the site from the north sea within the first few hundred years of the eemian corresponding to the pinus betula e1 or pinus betula ulmus e2 regional pollen assemblage zones rpaz by about 300 years beginning of rpaz e3 dinoflagellate cyst assemblages were already indicating summer sea surface salinities in excess of about 15 psu and temperatures that perhaps exceeded 27 c warm and saline conditions of 15 20 psu or more at least twice present levels persisted throughout the early eemian a rise in sea level at licze appears to correlate with a similar event in eastern denmark as both coincide with the increase in corylus ca 750 years into the interglacial this sea level rise might therefore have a basinwide extent and appears to correspond to an opening of the danish belts there is little if any evidence of arctic waters throughout the sequence whereas dinoflagellate cysts reflect sustained high salinites within the upper water column a concomitant increase in abundance of the chlorococcalean alga pediastrum within the carpinus corylus alnus e5 rpaz indicates an escalating freshwater input presumably from the proto vistula whose mouth was nearby this suggests the development of a thin seasonal low salinity surface layer below which dinoflagellates lived in more saline waters increasing fluvial influence suggests shallowing through rpaz e5 this study is the first to document dinoflagellate cysts from the eemian of the southeastern baltic sea and reveals a flora with distinctive lusitanian mediterranean affinities

how many oceans meliata vardar and pindos oceans in mesozoic alpine paleogeography the timing of rifting and subduction in the meliata vardar and pindos zones of the hellenic dinaric carpathian region indicates that they cannot be considered remnants of a single ocean basin in contrast to several recently published mesozoic paleogeographies sea floor spreading in the meliata zone culminated in middle triassic ladinian time and ceased in the late triassic and subduction occurred from this time until late jurassic closure in contrast sea floor spreading in the vardar zone began in early jurassic time and culminated in the middle jurassic and subduction occurred from latest jurassic time in the pindos zone sea floor spreading was initiated in the early triassic with late jurassic and early tertiary subduction

late cretaceous structural control and alpine overprint of the high sulfidation cu au epithermal chelopech deposit srednogorie belt bulgaria the chelopech epithermal high sulfidation deposit is located in the panagyurishte ore district in bulgaria which is defined by a nnw alignment of upper cretaceous porphyry cu and cu au epithermal deposits and forms part of the eastern european banat srednogorie belt detailed structural mapping and drillcore descriptions have been used to define the structural evolution of the chelopech deposit from the late cretaceous to the present the chelopech deposit is characterized by three fault populations including n55 n110 and n155 trending faults which are also recognized in the entire panagyurishte district mapping and 3 d modeling show that hydrothermal alteration and orebody geometry at chelopech are controlled by the n55 trending and n110 trending faults moreover the n155 trending faults are parallel to the regional ore deposit alignment of the panagyurishte ore district it is concluded that the three fault populations are early features and late cretaceous in age and that they were active during high sulfidation ore formation at chelopech however the relative fault chronology cannot be deduced anymore due to late cretaceous and tertiary tectonic overprint structurally controlled ore formation was followed by senonian sandstone limestone and flysch deposition the entire late cretaceous magmatic and sedimentary rock succession underwent folding which produced wnw oriented folds throughout the panagyurishte district a subsequent tectonic stage resulted in overthrusting of older rock units along ne trending reverse faults on the upper cretaceous magmatic and sedimentary host rocks of the high sulfidation epithermal deposit at chelopech the three fault populations contemporaneous with ore formation i e the n55 n110 and n155 trending faults were reactivated as thrusts or reverse faults dextral strike slip faults and transfer faults respectively during this event previous studies indicate that the present day setting is characterized by dextral transtensional strike slip tectonics the ne trending overthrust affecting the chelopech deposit and the reactivation of the ore controlling faults are compatible with dextral strike slip tectonics but indicate local transpression thus revealing that the chelopech deposit might be sited at a transpressive offset within a generally transtensional strike slip system the early wnw trending folds require a roughly nne ssw shortening which is incompatible with the present day dextral strike slip tectonic setting and the ne trending thrust formed during the tectonic overprint of the chelopech deposit this reveals a rotation of the principal stress axes after late cretaceous high sulfidation ore formation and post ore deposition of sedimentary rocks the nature of the sedimentary rocks interlayered and immediately covering the upper cretaceous magmatic rocks hosting the chelopech deposit indicates sedimentation and associated volcanism in an extensional setting immediately before ore formation it is concluded that the chelopech deposit was formed when the tectonic setting changed from extensional during late cretaceous basin sedimentation and magmatism to compressional producing wnw trending folds under a roughly nne ssw compression possibly in a sinistral strike slip system thus like other world class high sulfidation epithermal deposits the chelopech deposit was formed at the end of an extensional period or during a transient period of stress relaxation which are particularly favorable tectonic settings for the formation of high sulfidation epithermal deposits the exceptional preservation of the upper cretaceous chelopech epithermal deposit is explained by the combined deposition of a thick senonian sedimentary sequence on top of the upper cretaceous magmatic host rocks of the deposit and the later overthrust of older rock units on top of the deposit our study at chelopech supports previous studies stating that post ore basin sedimentation and tectonic processes provide the favorable environment to preserve old epithermal deposits from erosion the tectonic evolution of the chelopech deposit is similar to that of the entire panagyurishte ore district this coherence of the magmatic hydrothermal and tectonic events from north to south suggests that the ore deposits of the entire panagyurishte ore district were formed in a similar tectonic environment

last interglacial and early glacial circulation in the northern north atlantic ocean abstract studies of marine records from the northwestern european shelf and the northern north atlantic suggest that last interglacial environments were less stable in this area than in the mid latitude atlantic the influx of atlantic water masses to the northern north atlantic was generally higher and the meridional temperature gradient was steeper during the last interglaciation than during the holocene strong north south sea surface temperature gradients during the early weichselian indicate a generally low influx of atlantic water to the northern north atlantic even during interstades

post collisional rapid exhumation uplift and erosion during continental sedimentation indications from the late paleozoic salvan dorenaz basin western alps

post collisional rapid exhumation and erosion during continental sedimentation the example of the late variscan salvan dorenaz basin western alps the salvan dorenaz intramontane basin formed between ca 308 293 ma as an asymmetric graben along crustal scale transtensional fracture zones within the aiguilles rouges crystalline massif western alps and represents a feature of the post collisional evolution of the variscan orogens it contains 1 5 1 7 km of continental clastic deposits which were eroded from granitic volcanic and metamorphic rocks textural and compositional immaturity of the sandstones and the numerous lithic fragments with low chemical and physical stability suggest only short range transport 40ar 39ar analyses of detrital muscovite are interpreted to represent cooling of the crystalline basement below the respective closure temperatures ages from detrital muscovite range between ca 280 330 ma 40ar 39ar white mica plateau ages from granitic boulders range between 301 312 ma and suggest rapid cooling the very short time interval recorded between the 40ar 39ar cooling ages and the stratigraphic age of the host sediment suggests that considerable portions of the upper crust were removed prior to the formation of the basin late variscan granitic boulders document surface exposure and erosion of late carboniferous granites during early stages of the infilling of the basin therefore unroofing of basement units magmatic activity and formation of the fault bounded salvan dorenaz basin were acting concomitantly and are highly suggestive of extensional tectonics when compared with other orogens this situation seems specific to the variscan especially the exclusively young ages of detrital material however modern analogous may exist

spatial self organization in geomorphology from periodic bedforms and patterned ground to scale invariant topography a rich diversity of spatial order can be discerned in landforms and small scale features of landscapes with spatial order ranging in scale from 107 m to 10 2 m and in geometry from pronounced two dimensional periodicity to three dimensional scale invariance ripples of wind blown sand with their strikingly uniform spacing and mountainous topography with its fractal characteristics illustrate the range of geomorphic self organization patterns on the land surface are often very distinct easily observed and readily studied because of their accessibility and yet the systematic quantitative study of geomorphic self organization is only in its infancy it offers difficult challenges but also exceptional opportunities particularly for those versed in modern techniques used in studies of self organization in this overview diverse examples of spontaneous organization in geomorphic systems and recent pertinent studies are described starting with spatial structures that are generally most distinct and best understood they include 1 periodic structures that form on various substrates as water or air transports erodes and deposits sediments ripples and dunes meanders and bar pool topography of rivers and rhythmic shoreline features 2 polygonal patterns that result either from the growth cracks in such contrasting media as freezing lava and frozen ground or from freeze thaw alternations in soils 3 large scale periodic structures dictated by the deformation of magma or of the earth s crust linear arrays of evenly spaced volcanoes and sequences of alternating valleys and mountain ranges and 4 scale invariant structures revealed in drainage networks and topography

atlas of modern dinoflagellate cyst distributions in the black sea corridor from aegean to aral seas including marmara black azov and caspian seas abstract we present the first comprehensive taxonomic and environmental study of dinoflagellate cysts in 185 surface sediment samples from the black sea corridor bsc which is a series of marine basins extending from the aegean to the aral seas including marmara black azov and caspian seas for decades these low salinity semi enclosed or endorheic basins have experienced large scale changes because of intensive agriculture and industrialisation with consequent eutrophication and increased algal blooms the bsc atlas data provide a baseline for improved understanding of linkages between surface water conditions and dinoflagellate cyst dinocyst distribution diversity and morphological variations by cross reference to dinocyst occurrences in sediment cores with radiocarbon ages covering the past c 11 700 years the history of recent biodiversity changes can be evaluated the seabed cyst samples integrate seasonal and multi year data which are not usually captured by plankton samples and the cyst composition can point to presence of previously unrecorded motile dinoflagellate species in the bsc results show the presence of at least 71 dinocyst taxa of which 36 can be related to motile stages recorded in the plankton comparison with sediment core records shows that five new taxa appear to have entered or re entered the region over the past century statistical analysis of the atlas data reveals the presence of four ecological assemblages which are primarily correlated with seasonal and annual surface water salinity and temperature correlation with phosphate nitrate and silicate nutrients chlorophyll a and bottom water oxygen is less clear but may be important for some taxa biodiversity indices reveal strong west east biogeographical differences among the basins that reflect the different histories of mediterranean versus ponto caspian connections the atlas data provide a standardised taxonomy and regional database for interpreting downcore cyst variations in terms of quantitative oceanographic changes the atlas also provides a baseline for monitoring further changes in the bsc dinocysts that may accompany the accelerating development of the region

age and climate of the late saalian and early eemian in the type area amsterdam basin the netherlands abstract lake deposits of late saalian mis 6 and early eemian mis 5e age in glacially excavated basins in the central part of the netherlands provide a high resolution stable isotope and pollen record of the glacial interglacial transition late saalian warm conditions were interrupted by a cold dry interval at the saalian eemian boundary which we correlate to the kattegat stadial and heinrich event 11 this cold interval ties our continental climate record to that of the marine oxygen isotope based time scale oxygen isotope data from this sequence indicate that the subsequent early eemian saw a quick recovery to warm interglacial climatic conditions which was reached already during the pioneer phase of the vegetation the sea transgressed the lake 1 kyr after the start of the eemian and highstand was reached 2 kyr later precipitation increased just prior to transgression of the sea into the lake causing important changes in the vegetation transgression of the isostatically rebounding area once covered by the baltic ice sheet is of early eemian age and becomes younger from the former centre of the ice sheet along the baltic sea to its margin in the netherlands the highstand cannot precede the start of the eemian as the area was emerging assuming that the effect of the isostatic rebound is small along the margin of the former ice sheet and by using the australian u th ages of the eemian highstand coral reefs combined with the duration of the eemian pollen zones derived from the annually layered lake deposits of bispingen it is concluded that the eemian in the netherlands starts at 131 ka

scale matters a multi resolution study of the determinants of patterned ground activity in subarctic finland abstract numerical studies of earth surface processes in relation to their environment are one of the central topics in physical geography however collinearity between explanatory variables and spatial autocorrelation can hinder the detection of key environmental correlates underlying response explanatory variables relationships identified by traditional regression methods moreover conclusions about the potential importance of environmental variables have generally made on analysis conducted only at one spatial scale resolution in this study a variation partitioning method provided a framework to obtain new insights into the relative roles of different factors determining patterned ground activity at multiple spatial resolutions the variation in the distribution of the sorted and non sorted patterned ground was decomposed into independent and joint effects of relief soil and spatial variables geographical location based on a multi resolution system of 1 ha 25 ha and 100 ha cells covering in total 100 km 2 of a subarctic landscape in northern finland the independent effects of relief and soil variables captured the largest fraction of the variation in the non sorted patterned ground distribution while relief had a major contribution for sorted patterned ground activity the independent effect of spatial autocorrelation on sorted patterned ground was higher than that on non sorted patterned ground however a considerable amount of variation in the distribution of both patterned ground types was accounted for by the joint effects of explanatory variables and may thus be causally related to two or all three groups of variables our analyses produced often contradicting results at different resolutions consequently this has substantial implications for the study of geomorphological systems since the choice of resolution can have a major effect on the inferences of analyses our results draw attention to the roles of resolution and spatial autocorrelation in the study of geomorphological systems

paleoclimatic evidence for future ice sheet instability and rapid sea level rise sea level rise from melting of polar ice sheets is one of the largest potential threats of future climate change polar warming by the year 2100 may reach levels similar to those of 130 000 to 127 000 years ago that were associated with sea levels several meters above modern levels both the greenland ice sheet and portions of the antarctic ice sheet may be vulnerable the record of past ice sheet melting indicates that the rate of future melting and related sea level rise could be faster than widely thought

eemian interglacial record in the northwestern european part of the soviet union abstract in the territory under discussion the eemian period correlates with stage 5e of the deep sea record continental and marine beds of the interglacial have been identified at more than a hundred sites pollen stratigraphy at the sites includes seven assemblage zones of wide geographical extent the eemian climate was milder and more humid than today during the climate optimum the mean january temperature above the baltic was 4 8 c higher the author supports the theory on the connection between the eemian and white sea basins through the system of shallow sounds and the lakes of onega and ladoga the eemian deposits serve as an excellent key horizon for the study area furnishing a good basis for palaeoclimatic conclusions and speculations for the future

quantitative estimation of holocene surface salinity variation in the black sea using dinoflagellate cyst process length reconstruction of salinity in the holocene black sea has been an ongoing debate over the past four decades here we calibrate summer surface water salinity in the black sea sea of azov and caspian sea with the process length of the dinoflagellate cyst lingulodinium machaerophorum we then apply this calibration to make a regional reconstruction of paleosalinity in the black sea calculated by averaging out process length variation observedatfourcore sites fromtheblack seawithhigh sedimentation rates anddatedbymultiple mollusk shell ages results show averygradual change of salinity from w14 0 91 psu around 9 9 cal ka bp to a minimum w12 3 0 91 psu around 8 5 cal ka bp reaching current salinities ofw17 1 0 91 psu around

nonequilibrium geomorphic processes and deterministic chaos abstract disequilibrium is a common if not dominant condition in geomorphology and other environmental sciences because disequilibrium in a system implies a time lag time steps and time delays in simple deterministic equations may reflect process and such equations have been shown to result in chaos after examining some models of hillslope and catchment development we present an oversimplified model of a hillslope in which we calculate the elevation of a point at time t 1 as a function we consider both linear and nonlinear terms of the difference in elevation between it and the next uphill and downhill points at time t we show how this simple hillslope model will not produce chaos under one set of limiting conditions that do not include nonlinearity but without proof we note that in most conditions the hillslope mode is so similar to other models in which chaos arises because of disequilibrium that chaotic behavior is a likely possibility a formulation wherein the time step is in a weathering and or erosion coefficient rather than the elevation is also proposed

simulating arctic climate warmth and icefield retreat in the last interglaciation in the future arctic warming and the melting of polar glaciers will be considerable but the magnitude of both is uncertain we used a global climate model a dynamic ice sheet model and paleoclimatic data to evaluate northern hemisphere high latitude warming and its impact on arctic icefields during the last interglaciation our simulated climate matches paleoclimatic observations of past warming and the combination of physically based climate and ice sheet modeling with ice core constraints indicate that the greenland ice sheet and other circum arctic ice fields likely contributed 2 2 to 3 4 meters of sea level rise during the last interglaciation

40 ar 39 ar ages of detrital white mica from upper austroalpine units in the eastern alps austria evidence for cadomian and contrasting variscan sources five detrital white mica concentrates from very low grade metaclastic sequences within pre variscan basement and post variscan cover units of the upper austroalpine nappe complex eastern alps have been dated with 40ar 39ar incremental heating techniques to constrain the age of tectonothermal events in their respective source areas two samples from early palaeozoic sandstone exposed within the same alpine nappe record slightly discordant age spectra the maximum age recorded in one is 562 2 0 7 ma whereas the other yielded a 40ar 39ar plateau age of 607 3 0 3 ma these results indicate a source area affected by cadomian tectonothermal activity three detrital muscovite concentrates from post variscan late carboniferous and permian cover sequences exposed within three different alpine nappes yielded 40ar 39ar plateau ages of 359 6 1 1 ma 310 5 1 2 ma and 303 3 0 2 ma the contrasting detrital white mica ages are interpreted to reflect different source areas detrital muscovite from a post variscan carboniferous molasse type sequence and from a permian verrucano type sequence record ages which indicate late variscan e g 330 300 ma metamorphic sources by contrast detrital white mica from another permian verrucano type sequence suggests a source area affected by early variscan e g 400 360 ma metamorphism these results help clarify palinspastic relationships and tectonic correlations between pre late carboniferous metamorphic basement sequences and carboniferous to permian cover sequences

convection in a catastrophic flood deposit as the mechanism for the giant polygons on mars a formational mechanism for the large scale polygons that are defined by intersecting fractures in the northern plains of mars is proposed in this work the presented model is based on rayleigh convection of interstitial water driven by an unstable density temperature gradient within a saturated porous medium catastrophic emplacement of water rich sediments into the martian northern plain basins could have provided a thick sedimentary layer in which rayleigh convection could have occurred convection within this active layer is proposed to have differentially thawed an underlying ice rich permafrost layer that had been at the planet s surface before being rapidly buried the resulting morphology of the permafrost subsurface is thought to have resembled the scalloped solid liquid interface morphology produced in terrestrial convective flow visualization studies the exact size and shape of the scallops on the frozen subsurface would have been controlled by the dimensions of the convection cells which are estimated to have had width to depth ratios of between 3 4 and 4 5 subsequent stresses e g gravity and bending stresses would have produced maximum tensile stresses in the overlying sediments preferentially above the subsurface topographic highs as described previously by mcgill and hills 1992 additional desiccation of the sediments would have required contraction of the sediment cover and would have produced large scale polygonal fractures along the preexisting weaknesses located above the raised subsurface topography thus the underlying subsurface geometric morphology would have been translated to the surface and would be represented by the large scale polygonal fractures visible in the viking orbiter and mars global surveyor images of the martian northern plains

paleozoic tectonostratigraphic units of the northwest and central dinarides and the adjoining south tisia in the central dinarides and south tisia different paleozoic complexes occur in four geotectonic zones 1 comparatively autochthonous units located in the cores of disrupted anticlines of the external dinarides 2 allochthonous disrupted units accompanied by more predominant triassic formations in the sava nappe which is thrust onto the northeastern margin of the external dinarides 3 allochthonous disrupted units also together with triassic formations in the pannonian and durmitor nappes of the internal dinarides and 4 polymetamorphic sequences in basement of the pannonian basin and south tisia respectively this paper presents basic geological features for the main paleozoic areas included in these four zones the tectonostratigraphic units of the first two zones were related to the gondwana passive continental margin those of the third zone to the paleotethyan oceanic realm and those of tisia to the active laurussia margin geodynamic evolution of all these paleozoic complexes was related to opening and closure of the rheic and paleotethys oceans rifting processes along north gondwana started in the silurian locally in the cambrian ordovician and were followed by the late silurian devonian opening of the paleotethys subduction processes were active by the end of the devonian and at the beginning of the carboniferous along the laurussia margin they were followed during the westphalian by main variscan deformation during collision of gondwana and laurussia associated metamorphism was very low grade in the paleozoic units of the sava nappe low grade to epidote amphibolite grade within the paleozoic complexes of the pannonian and durmitor nappes in the internal dinarides and poly metamorphic with migmatites and granitoids in south tisia these processes gave rise to a pangea stage with the variscan basement disconformably overlain by late carboniferous and permian sediments

pollen stratigraphy of late pleistocene marine sediments at norre lyngby and skagen north denmark abstract two cores from north denmark norre lyngby 2 and skagen 3 have been investigated palynologically the sediment examined is correlated with the eemian interglacial stage oxygen isotope substage 5e and part of the early weichselian the skagen 3 core includes only the latter part of the interglacial the pollen assemblages in both cores significantly differ from nearby terrestrial records reflecting the nature of the depositional environment taphonomic processes and current regime during a time of higher eustatic sea level the upper part of the norre lyngby 2 core contains an assemblage which is correlated with the early weichselian brorup interstadial the norre lyngby 2 sequence also includes a characteristic sub biozone not seen in the danish terrestrial sequence which represents a climatic deterioration similar to that observed in the foraminiferal assemblages from the same samples the pollen sequence appears to have been influenced by changes in source area and surface water circulation which supports the interpretation of the cooling events given by the foraminiferal record

an analysis of eemian climate in western and central europe on the basis of 31 pollen diagrams and additional data for botanical macrofossils an analysis is made of the last interglacial eemian climatic history in western and central europe the main tool for this analysis is the climatic indicator species method only selected woody species are used for the quantification of data partial climatic range diagrams are presented for abies alba acer monspessulanum acer tataricum buxus sempervirens tilia tomentosa the problem of time correlation and pollen zonation of the eemian is discussed the climatic analysis itself is based on an improved version of the indicator species method in this version not every site is analysed for its climatic values instead maps and tables on the migrational history of hedera ilex buxus abies and species of acer tilia and abies are the basis for climatic maps showing respectively january and july isotherms for the periods of the corylus zone e4a and the carpinus zone e5 it is concluded that mean january temperatures were as much as 3 c higher at amsterdam the netherlands than at present and mean temperatures in july were 2 c higher however the thermal maximum in winter was later zone e5 than the summer thermal maximum zone e4a winter temperatures changed parallel to rise and fall of global sea level precipitation changes are more difficult to estimate in the first part of the eemian precipitation must have been relatively low but from zone e4b onward it increased to higher values reaching 800 mm and probably substantially more in zones e5 and e6 hence the eemian climate was in its beginning relatively more contintental and later from e4b onward more oceanic however as compared with the holocene the eemian climate was generally speaking more oceanic

rapid interglacial climate fluctuations driven by north atlantic ocean circulation recent data from the grip ice core1 3 in greenland suggest that the climate of the last eemian interglacial period was much less stable than that of the present interglacial rapid transitions between warm and cold periods were found to occur on timescales of just a few decades the north atlantic climate during the eemian period was also shown to be characterized by three states respectively warmer than similar to and colder than today1 2 recent data from the nearby gisp2 ice core have revealed some discrepancies with these findings which remain to be resolved4 5 here we present simulations using an idealized global ocean model which suggest that the north atlantic ocean has three distinct circulation modes each of which corresponds to a distinct climate state we find that adding a simple random component to the mean freshwater flux which forces circulation can induce rapid transitions between these three modes we suggest that increased variability in the hydrological cycle associated with the warmer eemian climate could have caused transition between these distinct modes in the north atlantic circulation which may in turn account for the apparent rapid variability of the eemian climate

multiproxy climate reconstructions for the eemian and early weichselian palaeobotanical coleopteran and periglacial data from 106 sites across northwestern europe have been analysed in order to reconstruct palaeoclimatic conditions during the eemian and early weichselian three time slices in the eemian and four in the early weichselian have been considered in the pinus quercetum mixtum corylus phase of the eemian summer temperatures were probably at their highest and the botanic evidence suggests a southeast to northwest gradient for both the warmest and coldest month coleoptera indicate that the summers in southern england were several degrees warmer than those of present day the climate during thecarpinus picea phase was uniform and oceanic without obvious gradients in the final time slice of the eemian the pinus picea abies phase temperatures of the warmest month seem to drop slightly with some indication of a shift towards a more boreal and suboceanic climate the reconstruction of the palaeoclimate in the herning stadial and rederstall stadial is hampered by the limited number of sites but botanical evidence suggests a gradient in temperature of the coldest month from east to west coleoptera from the herning stadial in central england and eastern germany suggest similarly cold and continental climates during the brorup interstadial and the odderade interstadial the botanical evidence suggests that the minimum mean july temperatures rose to 15 16 c but during the coldest month these temperatures show a gradient between 13 c in the east and 5 c in the west 1998 john wiley sons ltd

evidence of variscan and alpine tectonics in the structural and thermochronological record of the central serbo macedonian massif south eastern serbia the serbo macedonian massif smm represents a composite crystalline belt within the eastern european alpine orogen outcropping from the pannonian basin in the north to the aegean sea in the south the central parts of this massif south eastern serbia consist of the medium to high grade lower complex and the low grade vlasina unit outcrop and micro scale ductile structures in this area document three major stages of ductile deformation the earliest stage d1 is related to isoclinal folding commonly preserved as up to decimetre scale quartz feldspar rootless fold hinges d2 is associated with general south eastward tectonic transport and refolding of earlier structures into recumbent metre to kilometre scale tight to isoclinal folds stages d1 and d2 could not be temporally separated and probably took place in close sequence the age of these two ductile deformation stages was constrained to the variscan orogeny based on indirect geological evidence i e ca 408 ca 328 during this period the smm was involved in a transpressional amalgamation of the western and eastern parts of the galatian super terrane and subsequent collision with laurussia outcrop scale evidence of the final stage d3 is limited to spaced and crenulation cleavage which are probably related to formation of large scale open upright folds as reported previously 40ar 39ar thermochronology was applied on hornblende muscovite and biotite samples in order to constrain the age of tectonothermal events and activity along major shear zones these 40ar 39ar data reveal three major cooling episodes affecting the central smm cooling below greenschist facies conditions in the western part of the vlasina unit took place in a post orogenic setting extensional or transtensional in the early permian 284 1 ma the age of activity along the top to the west shear zone formed within the orthogneiss in the bo ica area of the vlasina unit was constrained to middle triassic 246 1 ma this age coincides with widespread extension related to the opening of the mesozoic tethys the greenschist facies retrogression in the lower complex probably occurred in the early jurassic 195 1 ma and it was related to the thermal processes in the overriding plate above the subducting slab of the mesozoic tethys ocean

marine dinocysts acritarchs and less well known npp tintinnids ostracod and foraminiferal linings copepod and worm remains

last interglacial eemian hydrographic conditions in the southwestern baltic sea based on dinoflagellate cysts from ristinge klint denmark a dinoflagellate cyst record with strong mediterranean lusitanian affinities is described from marine deposits of eemian age last interglacial late pleistocene at ristinge klint denmark revealing new information about the hydrographic evolution of the southwestern baltic sea a revised correlation of the pollen record at ristinge klint with that of the annually laminated site at bispingen in northern germany provides temporal control approximately the first quarter of eemian time is represented a marine ingression into a lake took place during the quercus rise about 300years into the interglacial and is marked by low c 3 psu salinities at the base of the cyprina clay that increased progressively an abrupt and significant rise in the inflow of warm saline waters from the north sea occurred at about 750 years into the interglacial the corylus rise and at about 1900 years into the interglacial strongly stratified waters developed higher in the cyprina clay and continuing to its top at nearly 3000 years into the interglacial more open marine waters are indicated although fully marine conditions were not reached the dinoflagellate record throughout the cyprina clay at ristinge klint is therefore one of increasing marine influence summer sea surface temperatures approached and may have exceeded 26 28 c during early eemian time indicating temperatures at least 5 c warmer than at present these warm conditions persisted to the top of the record at ristinge klint no evidence exists at ristinge klint for the influence of arctic watermasses and the paucity of cold water species throughout the section reflects mild winter temperatures in the southwestern baltic sea the new species spiniferites ristingensis is formally described and the name operculodinium centrocarpum var cezare de vernal goyette rodrigues 1989 is validated

geodynamic evolution of the central dinarides abstract the central part of the dinarides unlike the northwestern and southeastern dinarides shows a consistent pattern in the distribution of the large tectonostratigraphic units from southwest apulia to northeast the following five main units originating in different parts of the mesozoic tethys can be distinguished 1 adriatic dinaridic carbonate platform formations 2 carbonate clastic units flysch bosniaque of the passive continental margin 3 ophiolite bearing formations of the dinaridic ophiolite zone also containing radiolarites greywackes and shales including melange formations and overstepped late jurassic to cretaceous cover sequences 4 active continental margin units represented by upper cretaceous palaeogene trench sediments with blueschists tectonized ophiolite melange alpine medium pressure metamorphic rocks originated from upper cretaceous palaeogene sediments and alpine synkinematic granitoids 5 a nappe consisting of allochthonous palaeozoic triassic formations which is thrust onto the ophiolites and genetically related sedimentary formations the frontal parts of this nappe directly overlie the northeastern margin of the adriatic dinaridic carbonate platform i e the external dinarides the evolution of the central dinarides was controlled by a sequence of tectonic events which took place within the alpine cycle 1 rifting processes lasting some 40 50 ma which started in the late permian and ended in the norian 2 opening of the oceanic dinaridic tethys commenced in the late triassic and persisted for some 70 80 ma until the end of the jurassic 3 subduction processes and emplacement of ophiolites started in late jurassic early cretaceous times during the closing phase of the dinaridic ocean or dinaridic tethys the palaeozoic triassic nappe was emplaced on the ophiolites the thrusting was accompanied by alpine metamorphism 120 100 ma 4 the main alpine deformational event and medium pressure metamorphism with synkinematic granite plutonism took place in late eocene early oligocene times when the ophiolite and palaeozoic triassic nappes were emplaced on the adriatic dinaridic carbonate platform which at the same time was deformed resulting in the development of the external dinarides fold and thrust belt

silver base metal epithermal vein and listwaenite types of deposit crnac rogozna mts kosovo part i ore mineral geochemistry and sulfur isotope study abstract pb zn ag vein and listwaenite types of mineralization in crnac deposit western vardar zone were deposited within several stages i the pre ore stage comprises pyrite arsenopyrite pyrrhotite quartz kaolinite and is followed by magnetite pyrite ii the syn ore stage is composed of galena sphalerite tetrahedrite and stefanite and iii the post ore stage is composed of carbonates pyrite arsenopyrite and minor galena the vein type mineralization is hosted by jurassic amphibolites and veins terminate within overlying serpentinites mineralized listwaenites are developed along the serpentinite amphibolite interface the reserves are estimated to 1 7 mt of ore containing in average 7 6 lead 2 9 zinc and 102 g t silver sulfides from the pre and syn mineralization assemblage of the vein and listwaenite types of mineralization from the crnac pb zn ag deposit have been analyzed using microprobe crush leachates and sulfur isotopes the pre ore assemblage precipitated under high sulfur fugacities f s 2 10 8 10 6 bar from temperatures ranging between 350 c and 380 c most likely water rock reactions boiling and or increase of ph caused an increase of 34 s of pyrite toward upper levels within the deposit the decomposition of pre ore pyrrhotite to a pyrite magnetite mixture occurred at a fugacity of sulfur from f s 2 8 7 10 10 to 9 6 10 9 bar and fugacity of oxygen from f o 2 2 4 10 30 to 3 1 10 28 bars indicating a contribution of an oxidizing fluid i e meteoric water during pre ore stages of hydrothermal activity the crystallization temperatures obtained by the sphalerite galena isotope geothermometer range from 230 to 310 c the 34 s values of pre and syn ore sulfides pyrite galena sphalerite 34 s 0 3 5 9 point to magmatic sulfur values of 34 s of galena and sphalerite are decreasing upwards due to precipitation of early formed sulfide minerals post ore assemblage precipitated at temperature below 190 c based on data presented above we assume two fluid sources i a magmatic source supported by sulfur isotopic compositions within pre and syn ore minerals and a high mol of fluorine found within pre and syn ore leachates and ii a meteoric source deduced by coincident pyrite magnetite intergrowth sulfur isotopic trends within syn ore minerals and decrease of crystallization temperatures from the pre ore stage 380 350 c towards the syn ore 310 215 c and post ore stages

an overview and brief description of common marine organic walled dinoflagellate cyst taxa occurring in surface sediments of the northern hemisphere abstract organic walled resting cysts of planktonic dinoflagellates occur commonly in modern marine sediment where they represent with rare exceptions the only geologically preservable part of the life cycle although many species do not produce fossilizable resting cysts upper quaternary sediments contain a diverse cyst record that is used frequently for paleoenvironmental reconstruction and stratigraphic analysis reconstructions of past sea surface conditions rely on an understanding of the distributions of dinoflagellate cysts in modern sediments linked to their respective environmental parameters underpinned by sound taxonomy and standardized nomenclature stratigraphic studies additionally require knowledge of morphological details to distinguish extant from similar extinct taxa here 51 dinoflagellate cyst species and two informal cyst morphotypes that are commonly encountered during routine palynological analysis of upper quaternary marine sediments from the northern hemisphere are briefly described taxonomically and illustrated in addition their lowest stratigraphic occurrences are provided

exhumation of the central alps evidence from 40ar 39ar laserprobe dating of detrital white micas from the swiss molasse basin 40ar 39ar single grain laserprobe dating of detrital white micas from early oligocene to middle miocene 31 14 ma sedimentary rocks of the central swiss molasse basin reveals three distinct clusters of cooling ages for the hinterland two palaeozoic age clusters reflect cooling after the variscan orogeny with only limited reheating during the alpine orogeny the third tertiary age cluster reflecting late alpine cooling is restricted to sediments younger than 20 myr old micas with cooling ages 30 myr are interpreted to originate from the footwall of the simplon detachment fault thus representing formerly exposed upper levels of the present day lepontine metamorphic dome erosion of these levels is reflected by an increase of low grade metamorphic lithic grains in the sandstones this interpretation puts constraints on the timing of exhumation as well as on the evolution of the drainage pattern of the central alps

40ar 39ar ages of detrital white mica constrain the cenozoic development of the intracontinental qaidam basin china ar 39 ar dating of detrital white mica from cenozoic sediments from the nonmarine qaidam basin in western china yields several age groups these include 1 ca 350 450 ma 2 220 280 ma subordinate clusters with 3 122 140 ma and 4 a minor group ca 500 ma ages between 350 and 450 ma are the most common and dominating in the analyzed samples detrital mica in the western qaidam basin can be of a northern altyn mountains and or a southern qimantagh kunlun mountains provenance the main age group of 350 450 ma is well known from intrusions in the altyn mountains whereas the young ages 120 126 ma have been found within shear zones along the central kunlun and altyn tagh faults however hinterland sectors beyond the altyn tagh and central kunlun faults must be considered as potential source areas because the imbalance between the amount of basin fi ll to eroded basement material requires additional sources early paleozoic ages ca 500 ma have been documented so far only in the hongliugou suture zone north of the altyn tagh fault this suggests late or slow continuous uplift of the southern altyn range and because of sinistral slip along the altyn tagh fault further units of the same age are now exposed farther westward the age group of 220 280 ma has been documented only from the northern basin margin this age group may indicate recycling from triassic jurassic cover sequences of the altyn mountains or provenance from permian triassic granite bodies that possibly originated in the qilian mountains

evolution of late neoproterozoic to early paleozoic tectonic elements in central and southeast european alpine mountain belts review and synthesis abstract late neoproterozoic to early paleozoic cadomian tectonic elements are widespread in the southeastern alpine mediterranean mountain belts with discontinuous exposure extending from the alps to the menderes massif in turkey the sequences include voluminous plutonic island and continental arc successions some ophiolites of variable late neoproterozoic and cambrian to early ordovician ages high to medium grade metamorphic sequences and subordinate metasediments geological and geochronological data suggest that these cadomian elements partly experienced tectonothermal activity including metamorphism and magmatism between ca 650 and 600 ma followed by further i and s type plutonism in an andean type continental margin setting ca between 570 and 520 ma subsequently a major rift zone developed which resulted in continental stretching and subsequent formation of a back arc basin which is dated as late cambrian rifting is followed by oceanic spreading which commenced ca at the cambrian ordovician boundary possibly in a back arc setting this tectonic scenario suggests that alpine mediterranean cadomian tectonic elements were accreted to gondwana during early cadomian events ca 600 650 ma subsequently they were likely part of a long lasting outer subduction zone of gondwana at the margin of a panthalassa type ocean during late neoproterozoic iii and cambrian due to back arc spreading continental pieces started to split off from gondwana ca at the cambrian ordovician boundary

kinematics of foreland vergent crustal accretion inferences from the dinarides evolution one of the most common observation in mediterranean areas is the migration of contractional deformation and associated slabs through time towards external orogenic areas associated with lower plate crustal accretion the dinarides orogen of central europe is an optimal place to study such a sequence of contractional deformation compared with other areas contraction in the dinarides was less overprinted by subsequent extension while a remnant of the subducted slab is observed in a far external orogenic position understanding the deformational evolution of the dinarides is hampered by the reduced availability of kinematic studies therefore we have performed a surface kinematic study in the external parts of the dinarides by correlating with available geophysical and evolutionary constraints we constructed two large scale kinematically controlled regional transects the results demonstrate a long lived evolution of shortening that affected the dinarides lower orogenic plate while the late jurassic earliest cretaceous deformation was associated with an earlier obduction moment the latest cretaceous onset of continental collision has gradually focused deformation at inherited rheological weakness zones we show that shortening was interrupted by a period of miocene extension that affected all orogenic areas and created the dinarides lake system the extension was followed by renewed shortening that started during the latest miocene and remains presently active whose kinematics in the central and se part of the dinarides is revealed for the first time by our study these results indicate a lower plate crustal accretion mechanism that was spatially and temporally connected with gradual slab retreat in the dinarides

environmental change in the western iberia upwelling ecosystem since the preindustrial period revealed by dinoflagellate cyst records we present the first multi site study of dinoflagellate cyst records spanning ca ad 1860 2000 from the west iberian coast our aim was to reconstruct environmental changes in the western iberia upwelling ecosystem one of the most biologically productive areas in the world and an active fishery region a major shift in cyst assemblages was recorded off the northwestern shelf sector between 1920 and 1950 towards autotrophic dominance and consisted of a multi fold increase in total cyst concentrations and cysts of lingulodinium polyedrum accompanied by an increase in protoceratium reticulatum cysts the observed changes pre date the industrialization of agriculture in portugal and are concomitant with a shift in the north atlantic oscillation nao towards negative indices higher river input and increasing sea surface temperatures the southernmost record with reduced river and human influence showed only minor changes during the 20th century here an increase in protoperidinioid cysts after the

precise tracing of exhumation and provenance using 40ar 39ar geochronology of detrital white mica the example of the central alps

the last interglacial ocean the final effort of the climap project was a study of the last interglaciation a time of minimum ice volume some 122 000 yr ago coincident with the substage 5e oxygen isotopic minimum based on detailed oxygen isotope analyses and biotic census counts in 52 cores across the world ocean last interglacial sea surface temperatures sst were compared with those today there are small sst departures in the mid latitude north atlantic warmer and the gulf of mexico cooler the eastern boundary currents of the south atlantic and pacific oceans are marked by large sst anomalies in individual cores but their interpretations are precluded by no analog problems and by discordancies among estimates from different biotic groups in general the last interglacial ocean was not significantly different from the modern ocean the relative sequencing of ice decay versus oceanic warming on the stage 6 5 oxygen isotopic transition and of ice growth versus oceanic cooling on the stage 5e 5d transition was also studied in most of the southern hemisphere the oceanic response marked by the biotic census counts preceded led the global ice volume response marked by the oxygen isotope signal by several thousand years the reverse pattern is evident in the north atlantic ocean and the gulf of mexico where the oceanic response lagged that of global ice volume by several thousand years as a result the very warm temperatures associated with the last interglaciation were regionally diachronous by several thousand years these regional lead lag relationships agree with those observed on other transitions and in long term phase relationships they cannot be explained simply as artifacts of bioturbational translations of the original signals

climatic and anthropogenic impacts on the ria de vigo nw iberia over the last two centuries a high resolution dinoflagellate cyst sedimentary record abstract a high resolution dinoflagellate cyst record spanning the period of 1830 2012 ce from ria de vigo atlantic margin of nw iberia is presented changes in concentrations and percentages of dinoflagellate cysts and freshwater algal spores reflect climatic and anthropogenic influences on the ria i e coastal inlet formed by the partial submergence of a river valley statistical analyses pca and clustering were used to identify the main patterns of change in the cyst assemblages the cyst record was compared with reconstructed and measured instrumental environmental data nao temperatures mean sea level etc to support palaeo reconstructions four main phases were identified the first phase 1830 1855 ce of lower relative sea level rsl temperatures and precipitations represents the last stages of the lia little ice age the second phase 1855 1910 ce is interpreted as a transition between the colder lia and the wetter and warmer conditions that prevailed through the 20th century the third phase 1910 1975 ce is characterized by strong river inputs and water stratification in the ria and the fourth phase 1975 2012 ce reflects impacts of anthropogenic warming and pollution the anthropogenic signal consists of increases in heterotrophic cyst proportions and cysts diversity as well as of a marked decline of potentially toxic lingulodinium machaerophorum increasing organic matter content nutrients and industrial wastes have likely caused detrimental impacts on the autotrophic dinoflagellates by increasing turbidity and toxicity the b5 cyst record and its comparison with previously published data suggest that increased concentrations of l machaerophorum in the 20th century were mainly related to river flow variations that in turn were primarily driven by nao changes rather than cultural eutrophication we also report high abundances of peridinium ponticum in our record determining that this species is not exclusive to the black and marmara seas and has much wider natural distribution

last interglacial arctic warmth confirms polar amplification of climate change the warmest millennia of at least the past 250 000 years occurred during the last interglaciation when global ice volumes were similar to or smaller than today and systematic variations in earth s orbital parameters aligned to produce a strong positive summer insolation anomaly throughout the northern hemisphere the average insolation during the key summer months m j j was ca 11 above present across the northern hemisphere between 130 000 and 127 000 years ago with a slightly greater anomaly 13 over the arctic greater summer insolation early penultimate deglaciation and intensification of the north atlantic drift combined to reduce arctic ocean sea ice allow expansion of boreal forest to the arctic ocean shore across vast regions reduce permafrost and melt almost all glaciers in the northern hemisphere insolation amplified by key boundary condition feedbacks collectively produced last interglacial summer temperature anomalies 4 5 c above present over most arctic lands significantly above the average northern hemisphere anomaly the last interglaciation demonstrates the strength of positive feedbacks on arctic warming and provides a potentially conservative analogue for anticipated future greenhouse warming

development of miniature sorted patterned ground following soil erosion in east falkland south atlantic miniature sorted patterned ground features nets and stripes occur at an elevation of ca 35 m in the l antioja valley east falkland the features have developed following recent soil erosion and display many of the characteristics associated with the operation of frost related processes in regolith materials the patterns are currently active and indicate that in cool oceanic climates the distribution of frost sorted patterns is controlled by the presence of bare ground on suitable regolith rather than by altitude

the protomoesian microcontinent of the balkan peninsula a peri gondwanaland piece abstract based on differences in their pre palaeozoic and palaeozoic development the protomoesian microcontinent is divided into two terranes the balkan and the moesian a precambrian cambrian ophiolite island arc assemblage unconformably overlain by a palaeozoic sequence forms the first terrane the pre palaeozoic basement of the moesian terrane consists of proterozoic vendian metamorphics of continental origin the differences in the development of the palaeozoic rocks are also significant reason for dividing the balkan and the moesian terrane numerous features of the palaeozoic sediments palaeoclimatologic palaeobiogeographic palaeomagnetic from both terranes and the pan african affiliations of the ophiolite island arc assemblage identify the protomoesian microcontinent as a peri gondwanaland piece

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

differential frost heave model for patterned ground formation corroboration with observations along a north american arctic transect 1 frost boils in the arctic are a manifestation of patterned ground in the form of nonsorted circles active frost boils involve convection of water through the soil that can bring basic salts from depth to the surface as such active frost boils can mitigate acidification and thereby strongly influence the type of vegetation supported by arctic soils the presence or absence of active frost boils is thought to play a pivotal role in establishing the sharp demarcation between moist nonacidic tundra mnt and moist acidic tundra mat in the arctic the focus of this paper is to corroborate the predictions of a mathematical model that relates observable patterned ground features to ecosystem parameters with observations at the field sites along the north american arctic transect naat established by the biocomplexity of patterned ground ecosystems project model predictions indicate that recurrent one dimensional frost heave can become unstable and evolve into multidimensional differential frost heave dfh a laboratory frost heave simulation produced a 28 cm pattern in an active layer of 10 cm which agrees with linear stability theory predictions a finite element solution predicts three dimensional patterns with approximately 3 m spacing develop in a 1 0 m active layer with a surface n factor of 0 35 which agrees well with field observations from the naat the lack of significant frost boil activity in the mat is a result of suppression of dfh owing to denser surface vegetation characterized by low n factors prominent active frost boils are observed in the mnt at higher latitudes with more sparse vegetation characterized by higher n factors that promote dfh however at the northernmost field sites frost boils cannot be generated even though the n factors are relatively high owing to very rapid freezing conditions that mitigate dfh

overview of ophiolites and related units in the late palaeozoic early cenozoic magmatic and tectonic development of tethys in the northern part of the balkan region abstract the northern balkan peninsula including serbia montenegro bosnia croatia and the former yugoslavian republic of macedonia represents an excellent region for the study of tectonic processes related to mesozoic tethyan ophiolite genesis and emplacement we first summarise the main tectonic units of the northern balkan peninsula and then use this information to discuss tectonic processes including rifting sea floor spreading ophiolite genesis and emplacement melange accretion ocean basin closure and collision we then discuss alternative models of ophiolite genesis and emplacement for the region and suggest that multi ocean basin interpretations fit the data better than single ocean basin interpretations rifting of adria gondwana during the triassic created a rift in the south budva zone and opened a triassic oceanic basin further north dinaride ocean occurrences of inferred sub continental mantle lithosphere in the dinaride ophiolite belt e g zlatibor may record extensional exhumation within an ocean continent transition zone bordering the adria dinaride continent this was followed by emplacement together with ophiolites and melange during upper jurassic early cretaceous time upper triassic radiolarites and mid ocean ridge type basalts formed at a spreading ridge after continental break up the oceanic lithosphere of the dinaride ophiolite belt was partly generated above a subduction zone the metamorphic soles of the dinaride ophiolites formed during mid late jurassic mainly based on k ar dating widespread melange that is associated with the ophiolites represents a subduction complex controlled by tectonic accretion and sedimentary reworking in trench and fore arc basin settings a possible cause of jurassic dinaride ophiolite emplacement was collision of a subduction trench with a continental margin further north mesozoic oceanic lithosphere subducted northeastwards present coordinates opening a late jurassic marginal basin in the main vardar zone the dinaride ocean in the south closed during late jurassic early cretaceous time tithonian berriasian deformed oceanic crust melange and magmatic arc rocks further north main vardar zone were transgressed by mainly clastic sediments during the early cretaceous however part of the vardar ocean vardar zone western belt or sava zone remained partially open until latest cretaceous time generally northward subduction within this remnant ocean triggered further supra subduction zone ophiolite genesis during the late cretaceous the ocean closed by the maastrichtian followed by early cenozoic regional scale southward thrusting that locally intercalated older and younger mesozoic ophiolites and melanges future progress particularly depends on determining the crystallisation ages of the ophiolites obtaining better structural data on the direction of initial ophiolite emplacement and unravelling the palaeozoic tectonic development of the eurasian continental margin

a model for sorted patterned ground regularity sorted patterned ground refers to polygons nets or stripes defined by rocky borders which are the result of sorting in soil subjected to frost action this paper presents a model in which convection cells driven by unstable density stratification in the aqueous phase result in uneven melting of the underlying ice front during thawing the resulting undulatory ice front with regularly spaced peaks and troughs provides the pattern which results in the regularity observed for certain types of patterned ground in addition the model predicts the width to depth of sorting ratio for both polygons and stripes and explains the characteristic hexagonal shape of sorted polygons the transition from sorted polygons to sorted stripes on sloped terrain and the formation of sorted polygons under water the predicted ratio of width to depth of sorting of 3 81 for sorted polygons is compared with the ratio of width to depth of sorting of 3 57 found from a linear regression analysis of 18 field study data

a model for sorted circles as self organized patterns sorted circles emerge as self organized patterns from a laterally uniform active layer that becomes laterally sorted as frost heave deforms the interface between a stone layer and an underlying soil layer in a three dimensional cellular model of the active layer cyclic freezing and thawing drives transport of stone and soil particles by 1 addition of ice particles representing soil expansion by frost heave 2 removal of ice particles representing soil consolidation during thawing 3 addition of void particles a discrete abstraction of soil compressibility representing soil expansion by water absorption 4 removal of void particles representing compaction and desiccation of underlying soil by frost heave 5 relaxation of surface morphology by soil creep and stone avalanche and 6 vertical sorting of stones and soil by illuviation these transport processes give rise to sorted circles which are characterized by a mean spacing of 3 6 m a 2 4 m wide soil domain surrounded by a 1 0 m wide 0 3 m high annulus of stones and a 750 year period of circulation in the soil domain all consistent with measured characteristics of sorted circles in western spitsbergen in the model instabilities on the stonesoil interface grow upward as soil plugs by drawing in soil from the surrounding subsurface soil layer soil plugs develop into sorted circles as they contact the ground surface simultaneously elevating an encircling annulus of stones sorted circles are dynamically maintained by circulation within the stone and soil domains initiation of soil plugs is driven by a positive feedback in which frost heave near the stone soil interface pushes soil toward more compressible soil regions where the soil layer is thicker the lateral component of these frost heave induced displacements is not reversed during thaw because soil consolidation as ice rich soil melts and drains and soil expansion as desiccated and compacted soil hydrates displace soil vertically further development of soil plugs and sorted circles is determined by an interplay between this positive feedback and amplitude dependent negative feedbacks that result from decoupling of the freezing front from the stone soil interface parameters outside the range in which sorted circles form can result for example in stone islands and labyrinthine patterns the initial wavelength of perturbations on the stone soil interface is accurately predicted using a linear stability analysis but increase in this wavelength through time reflects the nonlinearities that control the spacing of soil plugs and sorted circles namely interactions and mergers between neighboring forms

hydrography and mollusc faunas of the baltic and the white sea north sea seaway in the eemian abstract palynologically dated mollusc and cirriped faunas from a region extending from the north sea through the baltic and karelia to the arkhangelsk region show that the hydrography of the baltic was very different from the holocene for 2 2 5 ka in the early eemian a seaway existed from the barents to the north sea through karelia until it was severed at the present continental watershed to the north of lake onega after this the ladoga onega trough remained an arm of the baltic for several millennia the benthic faunas are comparable to the holocene but their boundaries were displaced much further into the baltic notable differences from the holocene are the absence or rarity of the macoma balthica biocoenosis and the presence of cold portlandia dominated biocoenoses in karelia in the belt sea and western baltic winter sea surface temperatures and salinity were higher than now by ca 6 c and 15 and the distinctly brackish top layer was missing at the same time cold bottom water 2 5 c with a tendency to anoxia characterised the karelian arm of the baltic water exchange through this area was inhibited by the constriction to the north of lake onega and the basin and threshold bathymetry water transport through the white sea baltic seaway was too sparse to play an active role in the north atlantic surface circulation or climatic change in the region the high salinity and temperature in the belt sea and western baltic persisted throughout the eemian and are explained by wider and deeper passage from the north sea to kattegat wider straits through denmark higher salinity in the north sea higher evaporation as well as more dispersed fresh water supply the advection of oceanic water into the baltic culminated in the early eemian before the carpinus zone and probably resulted in an oceanic climate in the baltic region while at the same time cold winters produced cold bottom water in the karelian arm

salt fingering in subsea permafrost some stability and energy considerations salt fingering appears to be a viable mechanism for salt transport in the thawing layer talik above ice bonded permafrost near the seabed in the arctic shelves baker and osterkamp 1988 these saltwater infusions occur where concentrated brines overlie less concentrated or less dense brines at least two mechanisms exist which cause this condition near the seabed first salts rejected during sea ice growth result in the formation of a concentrated brine layer on the seabed and second salts rejected during sediment freezing near the seabed can result in a concentrated brine layer forming within the deeper and yet unfrozen sediments unstable salt fingering in a vertical tube containing a porous media is known to develop whenever the density gradient exceeds the critical value z 3 390 k gkb2 wooding 1959 this article presents a simple derivation and interpretation of this critical condition in terms of competing time scales a convective time scale represents the time required for formation of a vertical wedge shaped flow due to density differences and a diffusive time scale represents the time required to diffuse the density difference horizontally across the layer the critical density gradient is determined from a ratio of these time scales the stability criterion suggests downward salt fingering whenever the density gradient at prudhoe bay exceeds 6 2 10 5 g cm 4 in thawed subsea permafrost sediments maximum predicted velocity of the saltwater fingering is about 2 m d 1 and this is consistent with the direction and magnitude indicated by measurements of pressure gradients and numerical modeling in the thawing permafrost the energy dissipated by viscous forces in the thawed layer balances the potential energy added by the salt fingers caused by concentrated brines on the seabed

statistically assessing the correlation between salinity and morphology in cysts produced by the dinoflagellate protoceratium reticulatum from surface sediments of the north atlantic ocean mediterranean marmara black sea region and baltic kattegat skagerrak estuarine system abstract recent studies have correlated dinoflagellate resting cyst morphology to salinity and density variations in the water column suggesting that morphology can be used for paleoceanographic reconstructions however the univariate statistics used by these studies are appropriate only where morphology is related to a single variable density is a function of salinity and temperature so more advanced statistical methods are needed to understand which parameters affect morphology in this study based on surface coretop sediments a set of environmental variables sea surface salinity temperature nitrate and phosphate was simultaneously correlated to morphological variations seen in resting cysts produced by the dinoflagellate protoceratium reticulatum operculodinium centrocarpum sensu wall and dale approximately 3200 measurements were obtained from the north atlantic ocean and used to generate a working model based on the akaike information criterion hierarchical partitioning was then applied to establish the independent and joint effects for each predictor variable results from these analyses showed that while salinity constitutes the dominant variable affecting process length in the cysts of p reticulatum in the north atlantic it is not the sole explanatory variable and that multicollinearity exists temperature and nutrients also showed a significant relationship to the morphology requiring multiple regression to construct a representative model the applicability of the north atlantic working model was finally evaluated by comparing the results to data from the mediterranean marmara and black seas and baltic kattegat skagerrak estuarine system this comparison showed regional differences in morphological environmental correlation while salinity constitutes the most important explanatory factor in both the north atlantic and baltic skagerrak system this is not so for the mediterranean black sea region where temperature is the dominant variable it is concluded that a predictive salinity model based on p reticulatum cyst morphology has at best a regional application

differential frost heave and sorted patterned ground field measurements and a laboratory experiment abstract small scale sorted stripes and circles dominate over the alpine regions in the upper engadin swiss alps most of these features are spaced at less than 30 cm intervals by coarse margins shallower than 5 cm monitoring of sorted stripes indicates that shallow diurnal freezing often induces differences in amount and timing of frost heave by needle ice growth between fine and coarse stripes while deeper diurnal freezing and seasonal freezing rarely differentiate heave amounts of the two materials a laboratory simulation is designed to explore the contribution of differential frost heave to the sorting process at the monitoring site the device consists of a fine part loam and a coarse part a granule layer mounted on loam freeze thaw tests with a granule mantle of 0 5 2 5 and 5 cm thick demonstrate that the heave amount on the coarse part is greatly reduced by the 5 cm thick mantle and that the coarse part always heaves later but subsides earlier than the fine as a result of this time lag in frost heaving lateral soil movement towards the coarse part is generated within the surficial soil differential heave associated with diurnal freeze thaw cycles is capable of sorting of the top 5 cm of soil

contribution palynostratigraphique dinokystes pollen et spores a la connaissance de la mer de champlain coupe de saint cesaire quebec high resolution continental pollen and spores and marine dinoflagellate cysts microfloral records were obtained from a section consisting of about 0 5 m of glaciolacustrine and 2 5 m of champlain sea deposits at the saint cesaire site the pollen and spore assemblages indicate the existence of a regional open vegetation of shrub tundra to forest tundra fluctuations in the percentages of picea and shrub and herb taxa are related to regional afforestation and paleogeographical evolution of the basin the champlain sea sediments contain an abundant dinocyst flora dominated by operculodinium centrocarpum brigantedinium spp and algidasphaeridium minutum which indicate cold arctic conditions in surface waters fluctuations in concentration 102 104 cm 3 and relative abundance of dinocyst species are attributed to changes in dinoflagellate productivity and paleoceanographic conditions notably paleosalinity morphological variations of operculodinium centrocarpum and algidasphaeridium minutum led to

self organization of sorted patterned ground striking circular labyrinthine polygonal and striped patterns of stones and soil self organize in many polar and high alpine environments these forms emerge because freeze thaw cycles drive an interplay between two feedback mechanisms first formation of ice lenses in freezing soil sorts stones and soil by displacing soil toward soil rich domains and stones toward stone rich domains second stones are transported along the axis of elongate stone domains which are squeezed and confined as freezing soil domains expand in a numerical model implementing these feedbacks circles labyrinths and islands form when sorting dominates polygonal networks form when stone domain squeezing and confinement dominate and stripes form as hillslope gradient is increased

average process length variation of the marine dinoflagellate cyst operculodinium centrocarpum in the tropical and southern hemisphere oceans assessing its potential as a palaeosalinity proxy the study investigates the morphological variability of the dinoflagellate cyst operculodinium centrocarpum resting cyst of protoceratium reticulatum in core top samples distributed over the southern hemisphere and the tropics in relation to sea surface temperature sst and sea surface salinity sss at the corresponding sites the process lengths show a moderate inverse relationship to summer sst ssst r 0 44 and ssss ssst r 0 4 however lateral transport of cysts probably produced noise in the plots after excluding tropical and southern hemisphere sites considered to have been affected by long distance lateral transport the relationship between process length and density follows the equation sd 0 8422x 1016 9 r 0 55 with a root mean square error 0 63 kg m 3 while the negative correlation with ssst increases up to r 0 79 next to salinity this study thus highlights the importance of a second factor temperature affecting process length in the topics and the southern hemisphere oceans

problems of the duration of the eemian interglacial in europe north of the alps abstract suggestions that the duration of the eemian interglacial was about 11 000 yr based on annually laminated sediment sequences in germany have been challenged in favor of a much longer interval however biostratigraphic evidence demonstrates why the eemian sequences at grande pile and ribains cannot be reliably used for alignment with the marine sequence as applied by kukla et al 2002 this issue to estimate the duration of this interglacial the long chronology they propose would imply not just coniferous but for up to 5000 yr fully temperate forest in central france coexisting with treeless heath and steppe tundra conditions in northwestern europe an unlikely climatic and ecological scenario the proposal that the eemian interglacial in western europe lasted for 17 000 or even 23 000 yr is rejected a duration of no more than 13 000 yr is preferred at least for sites north of the alps and pyrenees the duration of temperate conditions in the mediterranean region is less certain

distribution of modern dinoflagellate cysts from inshore areas along the coast of southern norway surface sediment samples from inshore areas along the coast of norway from kragero in the south to kristiansund in mid norway were analysed for their dinoflagellate cyst content in order to establish a modern reference data base ultimately these data should furnish a firm foundation for dinoflagellate cyst research in the area in terms of both their spatial and their temporal records our aim is to build a data base containing reference samples from the various fjords and inshore areas along the entire norwegian coast dinoflagellate cysts have been recovered from all the samples studied and three main areas have been distinguished based upon their cyst assemblages the western part of skagerrak the southwestern coast of norway bordering the north sea and the west coast of norway bordering the norwegian sea the dinoflagellate cyst assemblages from these areas are most probably closely related to oceanographic parameters and reflect latitudinal or climatic trends along this stretch of the coast copyright 2001 john wiley sons ltd

eemian sea level highstand in the eastern baltic sea linked to long duration white sea connection abstract revised diatom and new dinoflagellate cyst and benthic foraminiferal data from the eastern baltic sea have refined our understanding of eemian last interglacial 131 119 5 ka sea level change on the russian karelia a former seaway linking the baltic to the white sea results from peski eastern baltic show the initiation of marine conditions just before 131 ka in the latest saalian after the opening of a connection to the north sea following the onset of the eemian marine highstand and the opening of the white sea connection at around 130 25 ka near fully marine conditions persisted in the eastern baltic area for ca 6 kyr until ca 124 ka for most of the eemian a strong thermal stratification in the eastern baltic resulted from an arctic and possible north atlantic water component from the white sea merging with warmer waters from the north sea from ca 124 ka decreasing salinity indicates the end of the marine highstand and a simultaneous closure of the baltic sea white sea connection i e a duration of ca 6 kyr for this seaway the main influence of white sea inflow appears to be restricted to the eastern baltic area although a large submerged area in the russian karelia associated with temperate atlantic waters could have assisted in creating a more oceanic climate for central europe

the role of subduction accretion processes in the tectonic evolution of the mesozoic tethys in serbia abstract ophiolitic rocks and melange occur in two belts in serbia to the northeast the vardar zone and to the southwest the dinaride ophiolite belt of the drina ivanjica belt which is interpreted as being a microcontinent rifted from apulia the tethys in the vardar zone has a long and complex palaeozoic early tertiary history that is still poorly understood ophiolitic rocks are known to have formed at least in the early late jurassic some of the extrusives apparently formed in a supra subduction zone setting based on immobile element geochemical evidence the mesozoic tethys in the vardar zone closed at least partly by the latest jurassic evidence from the apulian margin in the southwest and from the drina ivanjica belt further to the northeast shows that a small red sea type oceanic basin rifted in the late permian early triassic followed by spreading in the mid late triassic to early jurassic evidence from immobile trace elements shows that these extrusives are of mid ocean ridge and within plate type during the early late jurassic this southerly oceanic strand began to close creating melange as a classic subduction accretion complex morb and seamount type lavas channelised micaceous turbidites rare calciturbidites and large limestone masses capped by condensed successions were incorporated in the melange through tectonic processes many of these units originated at or near the southwestern margin of the drina ivanjica inferred microcontinent less deformed debris flows olistostromes reflect gravity reworking and or diapirism with accumulation mainly in perched basins above the subduction zone large overriding harzburgitic ophiolite thrust sheets may have developed in response to incipient spreading above a subduction zone dipping to the southwest these ophiolites were emplaced northeastwards complete with metamorphic soles in response to collision of the trench with the drina ivanjica belt southwest directed sliding of sediments into the foredeep took place prior to suturing in the tithonian and later transgression by clastic sediments

crustal structure at the contact of the dinarides and pannonian basin based on 2 d seismic and gravity interpretation of the alp07 profile in the alp 2002 experiment summary the area of this study includes the contact between the dinarides and the pannonian basin as a relation between the adriatic microplate and pannonian segment our analysis was carried out on profile alp07 which is a part of the alp 2002 experiment alp 2002 was large international seismic experiment that focused on the lithospheric structure of the eastern alps and surrounding areas profile alp07 is one of several refraction and wide angle reflection profiles located in the transition from the adriatic microplate through the dinarides and into the pannonian basin this 300 km long profile extends from istra croatia to the drava river at hungarian croatian border in a wsw ene direction it is oriented approximately perpendicular to the dinarides the main faults in the adriatic region and the contact between the dinarides and pannonian basin 2 d seismic modelling was done using tomographic inversion and ray tracing techniques the moho depth is the greatest in the area of the dinarides reaching about 40 km and is shallowest 30 20 km in the pannonian basin area at the boundary between these provinces the depth changes rather suddenly in order to obtain additional constraints on the crustal structure 2 d gravity modelling was also performed the layer boundaries were retained from the seismic model as there was no need to change them during modelling since varying densities in the model produced a good fit to the data a geological model was constructed based on both geophysical models three types of the crust were found along profile the dinaridic and the pannonian crusts that are separated by a relatively narrow transition zone the dinaridic upper crust is characterized by low seismic velocities and densities but its lower crust has high velocities and densities the pannonian crust can be seen as unique layer characterized by both low seismic velocities and densities large lateral and vertical changes in densities and seismic velocities can be found in the transition zone troughs in the seismic model at the level of the mohorovicic discontinuity are interpreted as major faults in the lithosphere three main lithospheric faults were identified in northeastern part of the dinarides under the sava depression and under the drava depression the first one may be considered as a result of subduction of the adriatic microplate under the pannonian segment similar movements are also defined within the transition zone where the pannonian segment is gradually rising over on the adriatic microplate

eemian climate fluctuations observed in a european pollen record recent ice core data from greenland1 2 suggest that the climate during the last interglacial period the eemian was more unstable than that of the holocene about 10 000 years ago to the present being characterized in particular by a series of cold episodes each lasting about 70 to 750 years subsequent analysis of a second greenland ice core3 4 however failed to corroborate the details of these eemian climate fluctuations a result that may be attributable to the effects of ice flow4 to resolve this discrepancy it is imperative to seek alternative sources of information about the eemian climate here we present climate reconstructions from pollen data from the annually laminated eemian lake sediment record at bispingen5 and from the eemian and holocene peat records at la grande pile6 the former record indicates that an initially warm period of 2 900 yr was followed by cooling and a series of colder episodes one of which had winter temperatures comparable to those at the end of the preceding cold stage the latter records show greater climate instability during the eemian than the holocene these results are in broad agreement with those from the grip ice core but contrast both with the gisp2 core3 4 and with recent high resolution marine records from the north atlantic7 8

laser 40ar 39ar dating of single detrital muscovite grains from early foreland basin sedimentary deposits in india implications for early himalayan evolution in india the dagshai and overlying kasauli formations represent the oldest exposed continental foredeep sediments eroded from the himalayan orogen 40ar 39ar dating of individual detrital white micas from these sedimentary units has provided maximum depositional ages of 28 ma for the dagshai formation at one locality and 25 ma at a second locality whereas deposition of the kasauli formation occurred after 28 ma at two localities and after 22 ma at a third locality this timing suggests that in india the start of substantial exhumation and erosion from the rising himalayan orogen was delayed until 28 ma

a review of rare and less well known extant marine organic walled dinoflagellate cyst taxa of the orders gonyaulacales and suessiales from the northern hemisphere abstract dinoflagellate resting cysts with rare exception produce the only discrete link between the biology of extant dinoflagellate species and their fossil record the geological preservability of such cysts allows them to be used for quantitative paleoecological reconstructions especially in the quaternary and for biostratigraphy and the calibration of molecular clocks with the geological record this contribution reviews and updates the taxonomy of 27 uncommon dinoflagellate cyst species and morphotypes belonging to the orders gonyaulacales and suessiales with occurrences in upper quaternary marine sediments of the northern hemisphere comparative descriptions and illustrations are provided along with the biological affinity of each taxon where known and lowest stratigraphic occurrence

episodic rapid uplift in the himalaya revealed by 40ar 39ar analysis of detrital k feldspar and muscovite bengal fan detrital k feldspar and muscovite samples from ocean drilling program leg 116 cores have been dated by the sup 40 ar sup 39 ar technique and have depositional ages from 0 to 18 ma from 4 to 13 individual k feldspars and 1 to 12 individual muscovites have been dated from 7 stratigraphic levels in every level at least one k feldspar and one muscovite yielded a minimum age identical within uncertainty to the age of deposition these results indicate that a significant portion of the material in the bengal fan is first cycle detritus derived from the himalaya therefore the substantial amount of sediment deposited in the distal fan in early to middle miocene time can be ascribed to a significant pulse of uplift and erosion in the collision zone at this time moreover these data indicate that throughout the neogene some part of the himalayan orogen was undergoing rapid erosion 1 to 10 mm yr this erosion must have been less than or equal to uplift relative to sea level the lack of granulite facies rocks in the eastern himalaya and tibetan plateau suggests to us that very rapid uplift must have been distributed in brief pulses over different parts of the mountain belt these datamore are incompatible with tectonic models in which the himalaya and tibetan plateau are uplifted either uniformly over the past 40 m y or mostly within the past 2 to 5 m y less

episodic exhumation in the western alps oligocene to miocene clastic sediments of the tertiary piedmont basin northwest italy were derived from erosion of western alps source rocks detrital white micas from dif ferent stratigraphic units and from sands of three present day rivers draining the internal western alps have been analyzed by 40 ar 39 ar geochronology our data suggest a wide spread fast cooling and exhumation event prior to ca 38 ma followed by a 30 m y period of slower cooling and exhumation combined with erosion of crustal rocks with uniform 40 ar 39 ar signatures these processes have resulted in a pattern of regularly increasing lag time up section