oxygen and carbon isotope signatures in late neogene horse teeth from spain and application as temperature and seasonality proxies abstract here we describe a data set of 249 stable o and c isotope compositions from fossil horse teeth from the upper neogene of central spain and discuss their potential as environmental proxies it has been shown before that horse tooth enamel 18 o is a good proxy for local meteoric water 18 o h2o which in turn bears a distinct relation to temperature during precipitation formation at mid to high latitudes we discuss the reconstructed 18 o h2o values and apply modern 18 o h2o temperature equations for the iberian peninsula to these values results for the early pliocene suggest mean annual temperatures up to 2 3 c higher than today fitting pollen based estimates fairly well temperatures 5 c higher than today are predicted for the early late miocene 11 9 ma these estimations are feasible given the local occurrence of crocodilians and the presence of fruit eating hominids in iberia at that time the estimated amount of cooling since then is similar to the estimated decrease in nw europe based on plants the stable carbon isotope record indicates the virtual absence of c4 plants pointing to an environment consisting of c3 plants under slightly water stressed conditions the long term 13 c trend follows the expected decrease in average global 13 c co2 predicted from planktonic foraminifers within tooth variability is supposed to reflect seasonal change but the amplitude is expected to have been significantly damped by internal time averaging effects related to the mixing with atmospheric o 2 reservoir dynamics enamel maturation and sampling procedure the exact degree of damping is difficult to estimate but theoretical considerations suggest values between 50 and 75 depending on temporal resolution and element used c o reconstructed seasonal temperature ranges for central spain are equal or slightly less than the modern range within tooth 13 c variation is more difficult to explain as it can be attributed to multiple factors such as intra annual changes in 13 c co2 micrometeorology plant response and diet the occurrence of both positive and negative intra tooth 18 o 13 c correlations may be related to orbitally forced variations in seasonality

synthesis of the quaternary in the almeria littoral neotectonic activity and its morphologic features western betics spain a sequence of marine and continental quaternary episodes is established as are their interrelationships the zone s tectonics have in most cases remained active to the present and control the factors all the tyrrhenian levels containing strombus bubonius are affected by the many faults that cross the lateral fringe and continue onto the shelf among these are the loma del viento fault n120 e a normal fault with certain leftward characteristics the el alquian faults n140 160 e which coincide according to several authors bousquet 1979 with the surface feature of a great dextral deep accident and the carboneras fault or the serrata fault n40 45 e left strike slip fault given the varying behaviour of the shoreline we have chosen to divide it into four sectors campo de dalias el alquian cabo de gata mojacar garrucha and campo de nijar serrata due to its geographical location no marine continental relationships exist in the latter a chart has been made in an attempt to synthesize the most significant stratigraphic genetic and tectonic characteristics of each sector lastly the influence of tectonics on the distribution and heights of the quaternary shorelines is clearly shown in a chart of the transgressive maxima of the tyrrhenian episodes

topography of the variscan orogen in europe failed not collapsed the variscan orogenic collage consists of three subduction collision systems rheno hercynian saxo thuringian and massif central moldanubian devonian to early carboniferous marine strata are widespread not only in the individual foreland fold and thrust belts but also in post tectonic basins within these foreland belts and on the cadomian crust of peri gondwanan microcontinental fragments which represent the upper plates of the subduction collision zones these marine basins preclude high elevations in the respective areas and also in their neighbourhood widespread late carboniferous intra montane basins with their coal bearing sequences are likewise incompatible with high and dry plateaus while narrow belts with high elevations remain possible along active margins within the orogen comparison of the variscides with the himalaya tibetan plateau is unfounded plausible reasons for the scarcity of high variscan relief include subduction of oceanic and even continental crust subduction erosion orogen parallel extension and most important lithospheric thinning accompanied by high heat flow and magmatism in many areas timing and areal array of magmatism and ht metamorphism are not compatible with a model of tectonic thickening and subsequent gravitational collapse it is suggested instead that lithospheric thinning and heating are due to mantle activities caused by the tethys rift the lower and middle crust were thermally softened and rendered unfit for stacking and isostatic uplift in terms of topography the variscides represent a failed orogen the ht regime also explains the abundance of granitoids and ht lp metamorphic rocks typical of the variscides melting in the ht regime extracted mafic components from variscan and cadomian crust as well as from cadomian metasomatized lithospheric mantle thus mimicking subduction related magmatism the onset of the ht regime at c 340 ma may also have triggered the final ascent of hp uhp felsic metamorphic rocks

intensive agriculture wetlands quarries and water management a case study campo de dalias se spain the intensive agricultural activities that have developed over the last 50 years in the campo de dalias almeria region have required large quantities of gravel and clay as the basic materials for the substrate over which crops are raised with this motive numerous gravel pits have been opened that have extracted several million cubic metres of material in recent years similar quantities of clay have been extracted from the distal sectors of the alluvial fans that descend from the sierra de gador and from within a large endoreic basin in the latter quarries some wetlands have developed probably because of the rise in the water table level in the aquifer over which they lie the gravel pits are situated in the apical sectors of the alluvial fans overlying hydrogeological units that are widely overexploited for this reason the gravel pits could be used for artificial recharge in addition to increasing the availability of water in the aquifer the risk of catastrophic flooding would also be reduced

observed connection between stratospheric sudden warmings and the madden julian oscillation 1 the effect of the madden julian oscillation mjo on the northern hemisphere wintertime stratospheric polar vortex and major mid winter stratospheric sudden warmings ssws is evaluated using a meteorological reanalysis dataset the mjo influences the region in the tropospheric north pacific sector that is most strongly associated with a ssw consistent with this ssws in the reanalysis record have tended to follow certain mjo phases the magnitude of the influence of the mjo on the vortex is comparable to that associated with the quasi biennial oscillation and el nino the mjo could be used to improve intra seasonal projections of the northern hemisphere high latitude circulation and in particular of the tropospheric northern annular mode at lags exceeding one month

hydrological factors in the interpretation of stable isotopic proxy data present and past a european perspective in the context of this paper stable isotopic proxies are those preserving directly or via known or calculable fractionation factors a record of 18o 16o and or 2h 1h in the water which contributed to their growth suitable proxies include amongst others tree ring cellulose bone phosphate lake sediment minerals and speleothem fluid inclusions a principal aim of studying isotopic proxies is to gain more information about past climates through a knowledge of how rainfall isotope compositions have changed over time however converting back from proxy to rainfall is not necessarily straightforward because however well the isotopic fractionation due to proxy growth or formation is understood a variety of modifying processes may have intervened between this and the actual rainfall events three main reservoirs of environmental water may contribute to the isotopic compositions of terrestrial proxy indicators surface waters soil moisture and groundwater each of these can in principle be isotopically modified compared to rainfall in the locality this review examines these effects and how they may change under different european climate types at the present day it is concluded that while groundwater isotopic compositions typically represent closely the bulk composition of rainfall under a variety of climatic regimes soil and particularly lake waters require detailed study if their isotope systematics are to be adequately understood the review also finds that to a large extent the present is the key to the past in terms of recharge processes during the late pleistocene though glaciation may have had profound isotopic consequences in certain areas while a more general aridity led to the apparent absence of recharge in most areas for much of the late devensian

contribution of environmental isotopes to the understanding of complex hydrologic systems a case study sierra de gador se spain determining the content of 18o and deuterium in the groundwater at the southern edge of the sierra de gador between october 1991 and march 1993 has enabled identification of the flow system of the waters the recharge and mixing processes and the possible mechanisms of salinization analysis of the precipitation indicates the dominant source and direction of the air masses the local meteoric water line that is established indicates a primarily mediterranean origin for the precipitation recharging the aquifers the variation of 18o content with altitude 0 35 per mille per 100 m enables an estimation of the principal recharge area which corresponds to a zone between 1200 and 1800 m a s l 1997 john wiley sons ltd

water temperature and conductivity variability as indicators of groundwater behaviour in complex aquifer systems in the south east of spain groundwater temperature and electrical conductivity logs were applied in this study to gain an understanding of the hydrogeological behaviour of a complex system this system compartmentalized by a large number of fractures which may even cause geothermal anomalies is that of the campo de dalias in the south east of the iberian peninsula in addition to this complexity one must consider the different levels with aquifer properties and their varying lithologies which in some cases are in direct contact with the sea vertical sections based upon the various logs allow lateral correlation to be made between the anomalies detected and provide information on the existence of both ascending and descending vertical flows and the inflow of sea water into the system analysis of environmental isotopes 18o and d indicate the areas of recharge with the greatest flow velocity no seasonal variation in the isotopes was observed which suggests that the residence time of the groundwater in the aquifer is several years radiocarbon dating gave estimates of generally long residence times although in some sectors it is possible to detect the current recharge based on its tritium content from rainwater infiltration or seawater intrusion copyright 2002 john wiley sons ltd

simulations of dynamics and transport during the september 2002 antarctic major warming abstract a mechanistic model simulation initialized on 14 september 2002 forced by 100 hpa geopotential heights from met office analyses reproduced the dynamical features of the 2002 antarctic major warming the vortex split on 25 september recovery after the warming westward and equatorward tilting vortices and strong baroclinic zones in temperature associated with a dipole pattern of upward and downward vertical velocities were all captured in the simulation model results and analyses show a pattern of strong upward wave propagation throughout the warming with zonal wind deceleration throughout the stratosphere at high latitudes before the vortex split continuing in the middle and upper stratosphere and spreading to lower latitudes after the split three dimensional eliassen palm fluxes show the largest upward and poleward wave propagation in the 0 90 e sector prior to the vortex split coincident with the location of strongest cyclogenesis at the model s lower boundary with an additional re

the influence of the quasi biennial oscillation on the troposphere in winter in a hierarchy of models part i simplified dry gcms abstracta dry primitive equation model is used to explain how the quasi biennial oscillation qbo of the tropical stratosphere can influence the troposphere even in the absence of tropical convection anomalies and a variable stratospheric polar vortex qbo momentum anomalies induce a meridional circulation to maintain thermal wind balance this circulation includes zonal wind anomalies that extend from the equatorial stratosphere into the subtropical troposphere in the presence of extratropical eddies the zonal wind anomalies are intensified and extend downward to the surface the tropospheric response differs qualitatively between integrations in which the subtropical jet is strong and integrations in which the subtropical jet is weak while fluctuation dissipation theory provides a guide to predicting the response in some cases significant nonlinearity in others particularly those designed to model the midwinter subtropical jet of the north pacific prevents its universal application when the ext

northern hemisphere mid winter vortex displacement and vortex split stratospheric sudden warmings influence of the madden julian oscillation and quasi biennial oscillation we investigate the connection between the equatorial madden julian oscillation mjo and different types of the northern hemisphere mid winter major stratospheric sudden warmings ssws i e vortex displacement and vortex split ssws the mjo ssw relationship for vortex split ssws is stronger than that for vortex displacement ssws as a result of the stronger and more coherent eastward propagating mjos before vortex split ssws than those before vortex displacement ssws composite analysis indicates that both the intensity and propagation features of mjo may influence the mjo related circulation pattern at high latitudes and the type of ssws a pronounced quasi biennial oscillation qbo dependence is found for vortex displacement and vortex split ssws with vortex displacement split ssws occurring preferentially in easterly westerly qbo phases the lagged composites suggest that the mjo related anomalies in the arctic are very likely initiated when the mjo related convection is active over the equatorial indian ocean around the mjo phase 3 further analysis suggests that the qbo may modulate the mjo related wave disturbances via its influence on the upper tropospheric subtropical jet as a result the mjo related circulation pattern in the arctic tends to be wave number one wave number two 25 30 days following phase 3 i e approximately phases 7 8 when the mjo related convection is active over the western pacific during easterly westerly qbo phases which resembles the circulation pattern associated with vortex displacement vortex split ssws

nature and timing of late mississippian to mid pennsylvanian glacio eustatic sea level changes of the pennine basin uk the pennine basin of northern england contains a comparatively complete serpukhovian moscovian succession characterized by high resolution ammonoid zonation and cyclic paralic sedimentation two new isotope dilution thermal ionization mass spectrometry zircon ages from a bentonite deposited during the arnsbergian mid serpukhovian regional substage and tonstein of earliest bolsovian early moscovian regional substage have been determined the weighted mean 206 pb 238 u ages of 328 34 0 55 and 314 37 0 53 ma total uncertainty respectively require modification of the time scale for the western europe regional chronostratigraphy the areal extent of acme ammonoid facies is used as a proxy for the magnitude of 47 discrete flooding events incised valleys major sequence boundaries are used as a proxy for the magnitude of sea level falls the frequency of these events in the light of the new radiometric dating indicates the following 1 there is temporal coincidence between major glaciations in gondwana and phases of increased frequency of sequence boundaries in the pennine basin 2 high amplitude flooding surfaces have an average frequency of c 400 ka 3 average cycle durations during the pendleian early arnsbergian and chokierian bolsovian of c 111 and c 150 ka respectively reflect short duration eccentricities 4 multiple flooding surfaces with the same ammonoid assemblages may equate with sub 100 ka precession or obliquity frequencies supplementary material u pb method description and data procedure for the calculation of the areal extent of marine bands and tables showing a full listing of biostratigraphical data used in the study are available at www geolsoc org uk sup18505

post variscan cooling history of the central western sudetes ne bohemian massif poland constrained by apatite fission track and zircon u th he thermochronology abstract apatite fission track aft and zircon u th he zhe dating techniques were combined to reveal post orogenic history of the rudawy janowickie mts in the west sudetes bohemian massif permian to jurassic zhe ages of 271 2 24 8 171 3 11 5 ma obtained for crystalline basement rocks indicate post orogenic cooling and progressive unroofing of the ne bohemian massif on the other hand cretaceous zhe ages of 130 5 8 8 99 7 6 7 ma prove that the rudawy janowickie mts region remained under 190 c during the mid cretaceous suggesting a deep burial zhe ages from the cretaceous sediments located to the east of the rudawy janowickie mts range between 298 8 16 8 and 181 8 11 9 ma documenting that the burial did not exceed 6 km in the axial part of the intra sudetic through aft ages range from 105 9 6 1 to 51 1 4 3 ma the eocene aft ages revealed by the granite basement and the cretaceous aft age revealed by the metamorphic cover suggest the existence of at least two different thermo tectonic blocks experiencing different post variscan cooling and exhumation aft results strongly support 3 3 3 5 km exhumation for the rudawy janowickie mts since the cenomanian which in combination with zhe results clearly contradicts some of the previously proposed evolutionary scenarios for the sudetes

contribution of time tracers mg2 toc δ13ctdic no3 to understand the role of the unsaturated zone a case study karst aquifers in the doubs valley eastern france 1 time tracers no 3 a toc d 13 c tdic mg 2 have been used to define the hydrodynamic behavior of a karst system high values in no 3 a and toc reflect rapid infiltration and consequently a short residence time within the aquifer whereas enriched d 13 c tdic and high mg 2 are expected for old water 9 springs and 5 boreholes have been sampled during three field campaigns in the doubs valley karst aquifer low water flood and recession periods a clear differentiation can be highlighted between boreholes characterized by a long residence time and springs that show a rapid infiltration considering only the springs values it appears that toc and d 13 c tdic contents can easily be correlated to the sampling period we show then the contribution of the unsaturated zone to the discharge during the low water period and the existence of reserves that seem badly connected to the drainage network and that contribute poorly to the minimal flow

high precision u pb zircon ca id tims dates from western european late visean bentonites three new u pb zircon chemical abrasion isotope dilution thermal ionization mass spectrometry dates obtained from late visean belgian bentonites are reported and are used to estimate the periodicity of early warnantian shallowing upwards carbonate parasequences that are interbedded with the dated bentonites early warnantian parasequences exhibit mean cycle periodicity values that are consistent with the c 100 ka milankovitch cycle which is the dominant milankovitch frequency recognized from recent pleistocene glacial records and thus strengthen the arguments for 1 these sedimentary cycles being of glacio eustatic origin and 2 the initiation of the main phase of late palaeozoic glaciation before the start of or during earliest warnantian times the new dates also provide additional high precision age constraints for the improved calibration of the mississippian time scale using the new dates the stratigraphical age of the clyde plateau volcanic formation midland valley of scotland is revised from holkerian to early asbian supplementary material u pb zircon ca id tims data tables and the method of the mean cycle periodicity calculations are available at www geolsoc org uk sup18747

a sims zircon age for a biostratigraphically dated upper visean asbian bentonite in the central european variscides bardo unit polish sudetes a lower carboniferous platform sedimentary sequence the paprotnia beds in the bardo unit of the central sudetes ne part of the bohemian massif sw poland is biostratigraphically well dated based on rich macro and micro fossil evidence as late visean late asbian crenistria go iii zone the beds contain several bentonite layers one of which was dated using the u pb shrimp method on volcanic zircons and yielded an age of 334 3 ma this date fits well to the recently established chronostratigraphic limits of the visean and is consistent with the newest isotopic age constraints of 336 5 332 ma for the asbian boundaries

barotropic wave propagation and instability and atmospheric teleconnection patterns abstract a global barotropic model linearized about the 300 mb climatological mean january flow is perturbed by applying a series of localized forcings distributed throughout the tropics and subtropics structures which resemble the observed pacific north american and east atlantic teleconnection patterns noted by wallace and gutzler 1981 tend to recur in the responses similar patterns are found to result from the dispersion of isolated initial perturbations placed at a variety of locations in the tropics and midlatitudes it is shown that these structures are related to the most rapidly growing mode associated with barotropic instability of the zonally varying climatological basic state in the absence of damping this mode has an e folding time of about a week and a period close to 50 days in localized regions the instantaneous growth rates can be competitive with those of baroclinic instability these episodes of rapid local barotropic growth are interspersed with intervals in which the local

the role of climate and aeolian dust input in calcrete formation in volcanic islands lanzarote and fuerteventura spain calcretes are widely described in non marine settings with carbonates in their catchment or vicinity areas but in volcanic islands without carbonates in their substrate calcretes are not very common in lanzarote and fuerteventura canary islands characterized by impressive volcanic landscapes the sedimentary carbonate rocks are rare except for some recent marine and aeolian deposits in these settings very well developed calcretes cover large areas of the present landscape the source of calcium required for the formation of these calcretes has not been discussed in much detail till now although its role is critical to an understanding of the climatic conditions in which calcium was transported and fixed and of the calcrete formation processes the petrological and geochemical studies 87sr 86sr ratios 13c 18o major trace and ree carried out in this paper do confirm the important role of aeolian dust input in the formation of these calcretes canarian calcretes were mainly generated by pedogenic processes and are composed of various irregular carbonate lamina interbedded with fine clastic deposits our study indicates that these interbeddings were the result of several stages in which during dry periods aeolian dust deposition alternated with leaching and calcite precipitation during wetter periods when plants insects and bacteria played an important role in carbonate precipitation the 18o 2 70 to 2 22 vpdb and 13c 8 21 to 0 24 vpdb values indicate that calcretes were formed by pedogenic processes comparison of calculated 18o values for the canary calcretes with continental mid latitude calcrete values reflects the more homogeneous temperature regimes of calcrete formation in island oceanic settings calcrete87sr 86sr ratios 0 706357 to 0 709208 show strong affinity with those obtained in aeolian carbonate dust and marine deposits and are relatively different from those obtained in basalts ree major and trace element concentrations show that ca bearing minerals from volcanic host rock contributed little to calcrete formation and most of the calcium was supplied by aeolian deposits such as the aeolian dust coming from the sahara and sahel or sand dunes

variation of the stable isotopes of water with altitude in the saint elias mountains of canada the stable isotopes of water measured in melt samples taken from snow pits and cores at locations between 1750 and 5930 m altitude on mount logan 5951 m and between 2900 and 4900 m on mount steele 5079 m in the saint elias mountains yukon show a distinctive altitudinal distribution several 18o and d versus altitude profiles indicate the general persistence of a nearly iso step or staircase structure separating a lower region of altitude dependent isotopic fractionation between 1750 and 3350 m from another apparent fractionation sequence appearing above about 5300 m both of these sequences but especially the lower one indicate orderly processes on the one hand postdepositional changes to isotope ratios in snow at different altitudes may cause distortions to an otherwise nearly monotonic isotope fractionation sequence but the main anomaly appears to be far too large to be explained in this way on the other hand an explanation linked to processes occurring in the lower and midtroposphere is based on established meteorological principles as well as on upper air data this hypothesis is proposed as the primary one to explain the gross features of the observed isotope profiles it is compatible with the concept of secondary source moisture arriving via the upper troposphere and it does not exclude the effects of postdepositional stratigraphic and stable isotope ratio changes over interannual time scales any vertical modulation of the observed isotope altitude structure from for example changes in wind regime would give rise to an additional signal in any ice core time series these findings identify a potential difficulty in the interpretation of stable isotope records obtained from high mountain ice core sites it is possible that the results may have application to atmospheric circulation modeling where the effects of extreme topography are being studied

development characteristics and dynamic structure of tropical intraseasonal convection anomalies abstract the development and dynamical structure of intraseasonal low frequency convection anomalies in the equatorial region are investigated using 10 years 1975 85 of outgoing longwave radiation olr and 7 years 1979 85 of 200 and 850 mb wind data the composite olr anomalies for 36 cases show a four stage development process initiation over equatorial africa rapid intensification when passing through the indian ocean mature evolution characterized by a weakening in the maritime continent and redevelopment over the western pacific and dissipation near the date line in moderate events or emanation from the equator toward north america and southeastern pacific in strong events a noticeable feature in vertical structure is that the 850 mb convergence leads convection and midtropospheric upward motion by about 30 degrees longitude in both developing and mature phases equatorial upper lower level easterly westerly anomalies and associated twin anomalous anticyclonic cyclonic circulation an

the influence of stratospheric vortex displacements and splits on surface climate abstracta strong link exists between stratospheric variability and anomalous weather patterns at the earth s surface specifically during extreme variability of the arctic polar vortex termed a weak vortex event anomalies can descend from the upper stratosphere to the surface on time scales of weeks subsequently the outbreak of cold air events have been noted in high northern latitudes as well as a quadrupole pattern in surface temperature over the atlantic and western european sectors but it is currently not understood why certain events descend to the surface while others do not this study compares a new classification technique of weak vortex events based on the distribution of potential vorticity with that of an existing technique and demonstrates that the subdivision of such events into vortex displacements and vortex splits has important implications for tropospheric weather patterns on weekly to monthly time scales using reanalysis data it is found that vortex splitting events are correl

global time scale and regional stratigraphic reference scales of central and west europe east europe tethys south china and north america as used in the devonian carboniferous permian correlation chart 2003 dcp 2003 the boundaries of the devonian carboniferous and permian stages of the global stratigraphic reference scale abbreviated to global stratigraphic scale gss are described in relation to the biostratigraphic and or lithostratigraphic units of the regional stratigraphic reference scales abbreviated to regional stratigraphic scales rss of central and west europe east europe tethys south china eastern tethys and north america in their type regions the boundaries of gss units rarely coincide with those of homonymous rss units moreover the definitions of some rss units have changed several times over the last decades and subsequent misunderstanding of the stratigraphical significance of these changes has often introduced errors into proposed global correlation charts the stratigraphic framework proposed in our global devonian carboniferous permian correlation chart 2003 dcp 2003 devonian carboniferous permian correlation chart 2003 menning m schneider j w alekseev a s amon e o becker g von bitter p h boardman d r bogoslovskaya m braun a brocke r chernykh v chuvashov b i clayton g dusar m davydov v i dybova jachowicz s forke h c gibling m gilmour e h goretzki j grunt t a hance l heckel p h izokh n g jansen u jin y g jones p kading k ch kerp h kiersnowski h klets a klug ch korn d kossovaya o kotlyar g v kozur h w laveine j p martens th nemyrovska t l nigmadganov a l paech h j peryt t m rohn r roscher m rubidge b schiappa t a schindler e skompski s ueno k utting j vdovenko m v villa e voigt s wahlman g p wardlaw b r warrington g weddige k werneburg r weyer d wilde v winkler prins c f work d m 2004 abschlusskolloquium dfg schwerpunktprogramm 1054 evolution des systems erde wahrend des jungeren palaozoikums im spiegel der sedimentgeochemie abstracts univ erlangen germany 2004 p 43 herein abbreviated to dcp 2003 and cited as dcp 2003 in references is an attempt to reduce these errors the dcp 2003 is the stratigraphic base for project 1054 of the deutsche forschungsgemeinschaft dfg the evolution of the late palaeozoic in the light of sedimentary geochemistry this composite time scale has been carefully balanced as far as data allows to remove unnecessary artificial compression and expansion of time intervals biozonations and depositional events the ages selected in dcp 2003 are markedly different to those in the geologic time scale 1989 gts 1989 harland w b armstrong r l cox a v craig l e smith a g smith d g 1990 a geologic time scale 1989 cambridge univ press cambridge harland w b armstrong r l cox a v craig l e smith a g smith d g 1990 a geologic time scale 1989 cambridge univ press cambridge pp 1 263 and in gradstein and ogg gradstein f m ogg j 1996 a phanerozoic time scale episodes 19 1 2 3 4 insert whereas they are closer to those of the geologic time scale 2004 gts 2004 gradstein f m ogg j g smith a g 2004 a geologic time scale 2004 cambridge univ press cambridge pp 1 589 mostly the ages are rounded to the nearest 0 5 ma in order to avoid estimates of questionable accuracy whereas ages of 0 1 ma in the gts 2004 and their error bars of 0 4 ma to 2 8 ma for the devonian to permian stage boundaries suggest an improved accuracy in contrast in the dcp 2003 questionable ages and positions of stratigraphic boundaries are marked by arrows c 2006 elsevier b v all rights reserved

influence of rainfall quantity on the isotopic composition 18o and 2h of water in mountainous areas application for groundwater research in the yunquera nieves karst aquifers s spain abstract the isotopic composition 18 o and 2 h of rainwater and groundwater was determined in the yunquera nieves hydrogeological unit a karstic massif in s spain with complex orography and hydrogeology the aims were to identify 1 the source of the water 2 the main factors determining the isotopic content 3 the catchment area of the springs and 4 the aquifer behaviour the isotopic content of the sampled waters is of mixed atlantic mediterranean origin and is opposite to the quantity of rainwater distribution both in space and time spatially water is isotopically less depleted toward the eastern sector where rainwater quantity is lower which is locally affected by the orography thus it is possible to differentiate the catchment areas of the main springs aquifer recharge is produced by winter precipitation when rainfall water is isotopically more negative and evaporation is lower the decrease in rainfall quantity during the study period provoked an increase in 18 o and 2 h values both in rainwater and in groundwater the recorded variations of the isotopic content of the rainfall are rapidly evident in the spring waters which demonstrates a well developed karst network inside the carbonate aquifers and thus the existence of conduit flow systems

spatial distribution of rock fragments in dolines a case study in a semiarid mediterranean mountain range sierra de gador se spain abstract rock fragments rfs at the soil surface have great effects on the intensity of various hydrologic and geomorphic processes however little information is available on the spatial distribution of rock fragments rf in the dolines which may be of importance in understanding overland flow and subsequent recharge in limestone karst landscapes this study analysed spatial variability of rf cover and size in different topographic positions top upper middle and lower position in three dolines in sierra de gador almeria province south east spain the results indicated that cover percentage of small rfs 5 20 mm increased but large rf cover 250 600 mm and 600 mm decreased from the upper position to the lower position of the dolines small rfs were usually resting on the soil surface while most large rfs tended to be partly embedded in the soil surface total rf cover and d 50 median diameter of the surface rfs greater than 5 mm tended to increase with slope gradient

comment on dorr and zulauf elevator tectonics and orogenic collapse of a tibetan style plateau in the european variscides the role of the bohemian shear zone int j earth sci geol rundsch 2010 99 299 325 the present comment disproves the tectonic model of a late devonian early carboniferous tibetan style collisional plateau in the tepla barrandean tb part of the bohemian massif which later collapsed by thermal weakening of the underlying crust contrary to this model the tb neither reveals major crustal thickening nor uplift and erosion and eastern continuations of the tb were during the relevant time span areas of open marine sedimentation late devonian early carboniferous marine sediments widespread also in the armorican and central massifs of france testify to low topography in central parts of the variscan orogen notional traces of a permo carboniferous ice cap on the french massif central do not support the plateau model because they are questionable and much younger than the inferred plateau stage of the tb the relative uplift of high grade metamorphic rocks to the nw and the se of the tb is not due to sinking of an elevated tb but instead to the hydraulic and buoyant expulsion of hp material from the saxo thuringian and moldanubian subduction channels the rise of lower grade ht rocks along the southwestern margin of the bohemian massif was effected by late carboniferous transpression the high temperature and the resulting low viscosity of the rising materials were probably not caused by variscan mantle delamination but relate to lithospheric thinning and heating at the tip of the westward propagating tethys rift

using stable isotope analysis δd δ18o to characterise the regional hydrology of the sierra de gador south east spain water stress is rapidly increasing in many mediterranean coastal zones mainly due to expansion in agriculture and tourism in this paper we focus on the sierra de gador campo de dalias aquifer system southeastern spain in order to assess the capability of water stable isotope analysis deltad delta 18 o to refine the understanding on recharge of this karstic aquifer system different types of surface and groundwater were sampled along an altitudinal gradient from the recharge zone in the mountains to the coastal plain surface water is restricted to local runoff collected in closed reservoirs runoff amounts collected in three of these reservoirs were monitored together with the precipitation in their catchments meteorological maps were used to detect the origin of the precipitation generating the majority of the runoff the results were compared to literature data on local and regional precipitation the use of oxygen and hydrogen isotopic composition has proved to be a useful tool to explain the origin of groundwater in a mediterranean karstic system such studies are however not numerous and are often limited to local scale recharge for fast reacting systems this paper focuses on the delta 18 o deltad relationships of local precipitation to explain the isotopic variability of a large karstic aquifer system the isotopic compositions of groundwater sampled along an altitudinal gradient from the recharge zone to the coastal plain are well displayed in a deltad delta 18 o diagram on a mixing line connecting a pole of mediterranean waters to a pole of atlantic waters the atlantic signature predominates in the shallow groundwater of natural springs reflecting the rainfall which produced the local runoff sampled the mediterranean signature is mainly restricted to deep groundwater from boreholes in the coastal plain the existence of a degree of spatial separation of groundwater types demonstrates that groundwater flow in a complex karstic system is not always continuous the mediterranean signature of deep groundwater could be due to past extreme rainfall events during which connectivity between recharge and reservoir exists while at the same time the atlantic signature of recent winter rains dominates in shallow groundwater the assumption that an equilibrium in isotopic composition is established within a continuous aquifer and that therefore a slope lower than 8 in a deltad delta 18 o diagram indicates evaporation is not necessarily valid c 2002 elsevier science b v all rights reserved

origin and type of rainfall for recharge of a karstic aquifer in the western mediterranean a case study from the sierra de gador campo de dalias southeast spain isotope signatures in precipitation from the global network for isotopes in precipitation around the mediterranean basin and literature data are compared with isotopic data from a large karstic aquifer in southeast spain to explain the origin and type of the precipitation events dominating recharge analysis of the deuterium excess d at the scale of the mediterranean basin and at the regional scale allows us to understand the isotopic context of the study area campo de dalias and the sierra de gador almerfa province the origin of precipitation can be determined from its d value the d value changes as a function of the initial evaporation condition it depends on the relative humidity and temperature during the evaporation producing the water vapour of the clouds the water vapour which dominates the study area is generated in two areas the atlantic ocean d 10 parts per thousand and the western mediterranean basin d 15 parts per thousand with increasing precipitation volume the western mediterranean character dominates these heavier storms contribute mainly to recharge as illustrated by the d value of 13 6 parts per thousand in deep groundwater of the campo de dalias weighted d values increase with the volume of precipitation giving a significant relationship for the southern and eastern coasts of the iberian peninsula this selectivity of d to monthly precipitation was used to estimate the return period of precipitation leading to aquifer recharge at 0 9 4 9 years moderate rainfall which occurs more frequently still represents similar to 60 90 of the total precipitation one of the challenges to meet ever growing water demands is to increase recharge from moderate events yielding intermediate quantities per event but forming the bulk of the annual precipitation copyright c 2006 john wiley sons ltd

planetary scale circulations forced by intraseasonal variations of observed convection abstract interhemispheric differences of the madden julian oscillation mjo are investigated in a linearized primitive equation model heating is prescribed from the observed life cycle of the mjo in which anomalous convection is concentrated in the eastern hemisphere the dynamical response in the eastern hemisphere has the form of a forced disturbance that involves kelvin and rossby components these dynamical components propagate eastward along with the prescribed heating and have zonal wavenumber 2 structure in accord with observed behavior the behavior in the eastern hemisphere also resembles that emerging from frictional wave cisk in which heating follows autonomously from the circulation when the prescribed heating collapses near the date line the rossby component dissipates the kelvin component however continues to advance across the western hemisphere where it propagates at more than twice the speed of the disturbance in the eastern hemisphere the disturbance in the western hemisphere

characterising flow regime and interrelation between surface water and ground water in the fuente de piedra salt lake basin by means of stable isotopes hydrogeochemical and hydraulic data summary this research reports the characterisation of ground and surface water interaction in the fuente de piedra salt lake basin in southern spain by a combined approach using hydraulic hydrogeochemical and stable isotope data during three sampling campaigns february 2004 2005 and october 2005 ground and surface water samples were collected for stable isotope studies 18 o d and for major and minor ion analysis hydraulic measurements at multilevel piezometers were carried out at four different locations around the lake edge conductivity logs were performed at four piezometers located along a profile at the northern lake border and at two deeper piezometers in the miocene basin at a greater distance from the lake to describe processes that control the brine evolution different hydrogeochemical simulations were performed hydrogeochemical data show a variety of brines related to thickness variations of lacustrine evaporites around the lake salinity profiles in combination with stable isotope and hydraulic data indicate the existence of convection cells and recycled brines furthermore restricted ground water inflow into the lake was detected dedolomitisation processes were identified by hydrogeochemical simulations and different brine origins were reproduced by inverse modelling approaches

controls of infiltration runoff processes in mediterranean karst rangelands in se spain semiarid karst landscapes represent an important ecosystem surrounding the mediterranean basin for which little is known on runoff generation knowledge of the sources and patterns of variation in infiltration runoff processes and their controls is important for understanding and modelling the hydrological functions of such ecosystems the objectives of this paper are to determine the infiltration rates and their controls in a representative mountain karst area sierra de gador se spain at micro plots and to investigate the integrated response of rainfall on a typical hillslope rainfall simulations in micro plots and natural rainfall runoff monitoring on a hillslope were carried out complementarily we investigated the role of soil surface components vegetation rock outcrop fracture and soil crust topographic position antecedent soil moisture and rainfall characteristics in regulating infiltration runoff processes results of rainfall simulation revealed the importance of vegetation cover and the presence of rock fractures in promoting the infiltration in the limestone karst landscape while bare patches and rock outcrops acted as sources for runoff all plots with 50 vegetation cover had no runoff with up to 55mmh 1 of simulated rain in contrast nearly all bare plots had runoff under the same simulated rain with runoff coefficients ranging from 3 1 to 20 6 on dry soil surface conditions and from 2 0 to 65 4 on wet soil surfaces runoff coefficients amounted to 59 0 79 5 for rock outcrops without cracks but were drastically reduced by the presence of cracks the surfaces with rock fragments resting on the soil generally located in the middle of the slopes prevented more effectively the runoff generation than those surfaces where rock fragments were embedded in the top soil antecedent soil moisture had significant impact on runoff generation with wet soil having doubled runoff coefficient shortened time to runoff and increased runoff rate compared to the same but dry soil linear regressions indicated that the main controls for constant infiltration rate were the cover percentages of vegetation and litter plus rainfall intensity while the major controls for runoff coefficient were the bare soil and vegetation coverage plus rainfall intensity high infiltration rates measured at the micro plots agreed with low intra event runoff coefficients mostly below 1 observed under natural rainfalls at the hillslope runoff depth and coefficient at the hillslope was significantly correlated with rainfall depth maximum hourly rainfall intensity and antecedent precipitation over 20days ap20 during the 1 5 year monitoring period from sep 2003 to mar 2005 the overall infiltration was 41 of the total rainfall amount and the maximum infiltration rate was almost 94 of the largest single rainfall event the results from this study contribute to improved understanding of the magnitude and controls of the surface runoff in semiarid karst mountain areas 2011 elsevier b v