types of carbonate aquifers according to the fracturation and the karstification in a southern spanish area the analysis of the fractures in the marble forming sierras blanca and mijas southern spain with faults of markedly different sizes and joints measured at 21 stations demonstrate the presence of two principal directions of fractures nnw sse and nne ssw other major directions of fractures although less distinct are n100e n120e and n60e the form of the karstic cavities known in these sierras was influenced by fractures fundamentally nnw sse and to a lesser extent nne ssw as well as by the mineralogical composition of the marble all the cavities known are located in blue limestone marble and appear to have formed by the end of the miocene principally during the pliocene and the pleistocene

indian continental subduction and slab break off during tertiary collision high wavespeed seismic anomalies in the transition zone and uppermost lower mantle beneath the india asia collision zone imaged by body wave seismic tomography have been interpreted as subducted fragments of continental material in this study we focus on the prominent anomaly located beneath india between depths of about 450 and 900 km by combining the location of this anomaly with palaeogeographical positions of india we constrain the timing of the subduction event probably related to this anomaly we infer that a large portion of the north western margin of india initiated subduction at 35 5 ma along a 1500 km long wnw ese striking zone and ended with a progressive slab break off process this break off started most probably around 25 ma at the western end of the slab and propagated eastwards until complete break off around 15 ma this study helps to constrain better the amount of convergence between india and asia absorbed by continental subduction

evaluating the impact of quarrying on karst aquifers of salento southern italy this paper describes a case study in the salento karst apulia southern italy in a site that has been intensively used to quarry limestones in the last 30 years after quarrying activity had stopped the site was transformed into legal and illegal landfills where solid and liquid wastes have been repeatedly dumped with serious consequences for the groundwater resources in this paper through a geological petrographical and hydrogeological approach we attempt to assess the consequences of the anthropogenic activities on the local hydrogeology with particular regard to the surficial aquifer that is contained in the plio quaternary calcarenites cropping out in the area application of some well known methods to assess the vulnerability of aquifer systems to contamination by human activities drastic sintacs legrand and god highlights the limits of such an approach in karst environment and the necessity to include in the methods data strictly related to the peculiarity of karst this is further evidenced by application of the epik method specifically designed for karst areas the final part of the paper focuses on the need of a thorough understanding of the hydrogeological setting for a better management and policy action of karst environments owing to a number of geological morphological and hydrogeological features karst is one of the most susceptible environments to negative impacts from human activities nicod 1972 white 1988 ford williams 1989 parise pascali 2003 as regards groundwater protection the intimate connection between surface and underground drainage and the rapidity of the surficial water to enter and percolate through the carbonate rocks result in a high intrinsic vulnerability of the karst aquifers this may favour fast movement of contaminants towards the water table and the resulting deterioration in groundwater quality sometimes with unrecoverable effects memon prohic 1989 kacaroglu 1999 escolero et al 2002 environmental damage and pollution in karst often derives from anthropogenic activities such as uncontrolled quarrying langer 2001 accompanying the growth of urbanization during the 20th century an accelerated pace of limestone quarrying has been registered in several areas of the mediterranean basin including italy bondesan meneghel 1990 gams et al 1993 gunn 1993 the most direct consequence of quarrying activity is the deterioration of the original karst landscape accompanied by the partial or total destruction of surface dolines and subsurface caves karst landforms with loss of the geological palaeontological and archaeological evidence therein present gillieson 1996 gunn 2004 in addition the quarry sites may later be used most of the times illegally as landfills to dump wastes of different kinds laws and management procedures generally do not take into account the peculiarity of karst environments ekmecki gunay 1997 lamoreaux et al 1997 daly et al 2002 and this results in the absence of adequate policy and management tools as well as in the uncertainty of the water authority to face an emergency the extent and complexity often not fully understood of catchment basins in karst represent the main problems in defining the areas of protection and frequently causes conflict between the rural environment and urban consumers nicod salomon 1999 bonacci 2004 in southern italy the salento peninsula fig 1 mostly made of carbonate rocks is dissected by an extensive network of quarries land use transformation and degradation of the karst environment have produced heavy modification in the natural landscape leading in many cases to pollution or to deterioration and partial destruction of natural sites including several caves this paper through description of the human impact in a sample site of salento and an evaluation of the consequences derived from the quarrying activity emphasizes the need to correctly manage such environment in order to preserve the natural landscape and water quality in karst aquifers from parise m gunn j eds natural and anthropogenic hazards in karst areas recognition analysis and mitigation geological society london special publications 279 153 171 doi 10 1144 sp279 13 0305 8719 07 15 00 the geological society of london 2007

long lasting intracontinental strike slip faulting new evidence from the karakorum shear zone in the himalayas terra nova 23 92 99 2011 abstract zircon crystallization ages for a syntectonic granite and an associated dyke along the tangtse strand of the karakorum fault are 18 5 0 2 and 18 6 0 2 ma respectively a dyke cross cutting the foliation in the karakorum shear zone ksz yielded an age of 16 0 0 6 ma these data show that the ksz was associated with significant granitic magmatism and was active before 16 ma since at least c 18 5 ma consideration of other data along the karakorum fault suggests that the fault has most likely been active since c 22 7 25 ma at a rate of 8 13 mm a 1 this study conducted in the frontal part of the himalayan orogen shows that large continental strike slip faults can be linked with magmatism and be stable for more than 20 ma even in the hottest part of the orogen where strain localization is supposed to be at a minimum

a new hydrogeologically based approach to determining protected areas in drinking water supply reservoirs a case study in the aglasun sub basin burdur turkey this study covers the hydrogeologically based works taking place in the drinking water reservoir drainage basin in the aglasun sub basin to ensure water quality the geological units in the aglasun sub basin are grouped under two units as allochthonous and autochthonous autochthonous units are composed of erenler limestone yazir formation inside reef limestone the aglasun formation seen as flysch and alluvium allochthonous units are composed of akdag limestone and ophiolitic complex autochthonous positioned limestones with their dissolution cavities are classified as karstic aquifers there is no hydraulic relationship between autochthonous positioned limestones and drinking water reservoir allochthonous positioned limestones are classified as karstic aquifers having large number of spring discharges in the studied basin a groundwater vulnerability map has been prepared which is an effective tool in determining the water resource protection areas the drastic method was used when preparing the groundwater vulnerability map the groundwater depth net recharge aquifer type soil media topography vadose zone effect and hydraulic conductivity parameters were used to form thematic maps and were evaluated with the help of arcgis technology the most sensitive areas to groundwater are distinctively the areas covered with alluvium and allochthonous limestone springs discharging from these sensitive areas recharge the stream that connects to the reservoir it is therefore understood that the traditional protection areas determined after the maximum water level are inadequate in protecting the water quality in a drinking water basin in addition to existing protection zones this study suggests hydrogeologically based new protection areas which also include streams flowing into the reservoir

intrinsic vulnerability assessment of saturnia thermal aquifer by means of three parametric methods sintacs gods and cop three different parametric methods for the evaluation of intrinsic vulnerability to pollution have been applied in a hydrothermal carbonate aquifer located in central northern italy and the results obtained were compared with each other the study area large approximately 152 km2 lies in an area of the northern apennines the investigated aquifer feeds the hot thermal springs of saturnia the vulnerability assessment methods used are sintacs gods and cop the vulnerability maps obtained were first individually examined and then they were compared with each other by means of spatial analysis these maps show similar results for the estimation of the vulnerability just in some areas sintacs yields areas potentially vulnerable to pollution along the albegna river and its major tributaries in the northern part of the study area the gods index map reflects the great importance that this method gives to the lithological characteristics of the unsaturated zone in the subdivision of areas with different vulnerability gods and cop methods agree in classifying low vulnerability in the most part of central southern study area where the aquifer is confined by the pliocene clay deposits based on the conceptual model of groundwater flow developed for the aquifer under investigation cop seems the most appropriate method among those applied in this work in particular with regard to the assessment of the vulnerability of the recharge area of thermal groundwater located in the northern part of the study area where karst carbonate formations of the tuscan nappe outcrop this recharge area is classified by the cop method as highly vulnerable to pollution

three dimensionality of slab detachment due to ridge trench collision laterally simultaneous boudinage versus tear propagation the detachment of subducted tectonic plates is a process that has been increasingly associated with collisional scenarios and the end of subduction in various locations worldwide in particular the propagation of slab detachment tearing of a subducting plate has been described in conceptual models as a cause for spatially and temporally progressing surface effects such as slab gap volcanism and uplift however there is little understanding of the causes and dynamics associated with three dimensional 3 d slab tearing especially in the case of ridge trench collision here we show using fully dynamic 3 d numerical models that the process of detachment due to ridge trench collision depends on the geometry of the ridge segments approaching the trench for a finite laterally symmetric slab the 3 d detachment process occurs nearly simultaneously along strike by way of boudinage type necking and opening of holes central to the slab for a case involving the approach of two offset ridge segments to the trench slab tearing occurs in the form of 1 a vertical propagating separation along the age offset boundary within the slab that was previously weakened by a transform weak zone and 2 horizontal propagating detachment controlled by lateral transfer of slab pull to adjacent surface plate segments however lateral decoupling between offset adjacent plate segments and the propagating nature of the vertical and horizontal tearing are dependent upon fracture zones remaining weak through the subduction zone whether detachment occurs simultaneously along strike or propagates laterally the process is controlled by plastic yielding of the slab interior when young lithosphere entering the trench can no longer support slab pull

insights on the kinematics of the india eurasia collision from global geodynamic models the eocene india eurasia collision is a first order tectonic event whose nature and chronology remains controversial we test two end member collision scenarios using coupled global plate motion subduction models the first conventional model invokes a continental collision soon after 60 ma between a maximum extent greater india and an andean style eurasian margin the alternative scenario involves a collision between a minimum extent greater india and a neotethyan back arc at 60 ma that is subsequently subducted along southern lhasa at an andean style margin culminating with continent continent contact at 40 ma our numerical models suggest the conventional scenario does not adequately reproduce mantle structure related to tethyan convergence the alternative scenario better reproduces the discrete slab volumes and their lateral and vertical distribution in the mantle and is also supported by the distribution of ophiolites indicative of tethyan intraoceanic subduction magmatic gaps along southern lhasa and a two stage slowdown of india our models show a strong component of southward mantle return flow for the tethyan region suggesting that the common assumption of near vertical slab sinking is an oversimplification with significant consequences for interpretations of seismic tomography in the context of subduction reference frames

segmentation of the farallon slab abstract recent tomography images reveal a complex 3d mantle structure beneath western united states with feature morphology varying rapidly with depth by assimilating plate motion history paleo age of sea floor and paleo geography of plate boundaries in a 3 d numerical model we simulate the farallon juan de fuca subduction during the past 40 ma we find that the highly segmented upper mantle structure of western u s is a direct result of the farallon subduction we show that the tilted horseshoe shaped fast seismic anomaly beneath nevada and utah at 300 600 km depth range is in fact a segment of curled slab subducted since 15 ma and the shallower linear slab beneath the cascades is younger than 5 ma the distinct morphology between these two parts of the subduction system indicates the strong influence of the fast trench rollback since 20 ma the northward migrating jf pa na triple junction and the toroidal flow around slab edges the observed mantle structures are used to constrain the rheology of the upper mantle through matching the shape depth and location of modeled subducted slab segments the inferred viscosity for the asthenosphere is 5 10 19 pa s and those for the transition zone and lower mantle are 1 5 10 21 pa s and 2 10 22 pa s respectively the slab is found to be about 2 orders of magnitude stronger than the ambient mantle above 410 km depth but of similar order of magnitude viscosity in the transition zone

imaging the colliding indian and asian lithospheric plates beneath tibet 1 a high resolution image of the base of the lithosphere from s to p converted seismic waves revealed the collision architecture of the indian and asian continental plates beneath the tibetan plateau the base of the indian lithosphere dips northward from a depth of 160 km beneath the himalayas to a depth of 220 km just south of the bangong suture the base of the asian lithosphere is nearly horizontal at the depth of 160 180 km from central to northern tibet there is a vertical gap of about 50 km between indian and asian lithospheres our observation of a well defined thick lithosphere throughout the entire plateau is not consistent with models of wholesale convective instability of a thickened mantle lithosphere which would predict a very thin asian lithosphere the hypothesized sequential southward subduction of tibetan and asian continental lithospheres leading to the growth of the tibetan plateau if correct cannot be occurring below 180 km depth our results along with available geological and geophysical data strongly support that the plateau is predominantly formed by a relatively coherent north dipping subducted indian continental lithosphere in the south which presently can be traced to the middle of the plateau and a south dipping subducted asian lithosphere in the north at a shallower depth

comparative application of two methods cop and paprika for groundwater vulnerability mapping in mediterranean karst aquifers france and spain a comparative test of two vulnerability mapping methods cop and paprika specifically dedicated to for karst aquifers was carried out on two mediterranean carbonate aquifers the vulnerability maps obtained for each aquifer present important differences to identify and determine the origin of these differences the results were statistically analyzed using sensitivity analysis coefficients of determination and scatter graphs in addition the global vulnerability gv parameter was used to measure the general vulnerability of the aquifer and to compare the results obtained this statistical analysis led us to conclude that the main cause of differences between these two methods used to assess aquifer vulnerability lie in the relative importance of the parameters employed in calculating the vulnerability index for the paprika method the variable related to infiltration slope and karst features has the most influence with less weight being assigned to the protective capacity of layers overlying the aquifer for the cop method the most influent variable is defined by the layers overlying the aquifer together with infiltration characteristics determined by the relative importance of different forms of infiltration in each aquifer the vulnerability mappings performed using the cop method present greater coherence with the known hydrogeological behavior of the study areas especially the spanish aquifers nevertheless further hydrogeological investigations are needed such as ones to validate the obtained vulnerability maps

influence of trench width on subduction hinge retreat rates in 3 d models of slab rollback subduction of tectonic plates limited in lateral extent and with a free trailing tail i e free subduction is modeled in a three dimensional 3 d geometry the models use a nonlinear viscoplastic rheology for the subducting plate and exhibit a wide range of behaviors depending on such plate characteristics as strength width and thickness we investigate the time evolution of this progressive rollback subduction measure the accompanying return flow in the upper mantle and quantify the plate kinematics due to the 3 d geometry flow is allowed to accompany slab rollback around the lateral edges of the slab the toroidal component as opposed to 2 d geometry where material is forced to flow underneath the slab tip the poloidal component a simple force balance is provided which relates the speed of backward trench migration to the resistive forces of generating flow and weakening the plate our results indicate most of the gravitational energy of the system i e the negative buoyancy of the subducting slab is converted into a toroidal flow 69 a much smaller amount goes into weakening the plate 18 and the remaining amount goes into driving flow parallel to displacement of the slab 13 for the trench widths w we investigate 1500 km a maximum trench retreat rate occurs for trenches 600 km wide which is attributed to the interaction between a plate of finite width and the induced flow which has a lengthscale in the horizontal direction these numerical results quantitatively agree with comparable 3 d laboratory experiments using analogue models with a purely viscous plate material schellart 2004a 2004b including correlations between increasing retreat rate with increasing plate thickness trench width for maximum retreat rate 500 km and estimated amount of slab buoyancy used to drive rollback induced flow 70 several implications for plate tectonics on earth result from these models such as rollback subduction providing a physical mechanism for ephemeral slab graveyards situated above the more viscous lower mantle and endothermic phase transition prior to a flushing event into the lower mantle mantle avalanche

the geological evolution of the tibetan plateau the geological evolution of the tibetan plateau is best viewed in a context broader than the india eurasia collision zone after collision about 50 million years ago crust was shortened in western and central tibet while large fragments of lithosphere moved from the collision zone toward areas of trench rollback in the western pacific and indonesia cessation of rapid pacific trench migration 15 to 20 million years ago coincided with a slowing of fragment extrusion beyond the plateau and probably contributed to the onset of rapid surface uplift and crustal thickening in eastern tibet the latter appear to result from rapid eastward flow of the deep crust probably within crustal channels imaged seismically beneath eastern tibet these events mark a transition to the modern structural system that currently accommodates deformation within tibet

subduction and slab breakoff controls on asian indentation tectonics and himalayan western syntaxis formation 1 we test the link between large scale asian continent deformations and indian slab subduction and breakoff during convergence by means of three dimensional numerical models of the subducting upper plates system we find that the subduction of the buoyant continent results in the reduction of convergence velocity comparable to that observed in the indian motions yet the upper plate deformation remains accommodated in a narrow belt along a straight margin comparable rates are measured when the subducting slab breakoff is modeled although the convergent margin deforms and curves markedly with large underplating contiguous to ongoing subduction similar to what observed along the himalayan range the models support the interpretation of the himalayan western syntaxis evolution the progressive curvature of the indian margin and the underthrusting as a consequence of the indian slab breakoff the modeled slab detachment is followed by short lived large stresses in the upper plate interiors propagating at large distance from the margin with a trend similar to several major asian lithospheric faults such localized stress has likely provided the conditions for the formation of the central asian intracontinental faulting the bangong red river and the altyn tagh faults that followed successive indian slab breakoff episodes continent subduction and breakoff during india asia convergence offer an explanation for the different deformation mechanisms as the long lived understhrusting and the episodic lithospheric faulting in the asian continent and their link to deep processes

crustal and uppermost mantle velocity structure along a profile across the pamir and southern tien shan as derived from project tipage wide angle seismic data summary utilizing seismic refraction wide angle reflection data from 11 approximately in line earthquakes 2 d p and s velocity models and a poisson s ratio model of the crust and uppermost mantle beneath the southern tien shan and the pamir have been derived along the 400 km long main profile of the tipage tien shan pamir geodynamic program project these models show that the crustal thickness varies from about 65 5 km close to the southern end of the profile beneath the south pamir through about 73 6 km under lake karakul in the north pamir to about 57 7 km 50 km south of the northern end of the profile in the southern tien shan average crustal p velocities are low with respect to the global average varying from 6 26 to 6 30 km s 1 the average crustal s velocity varies from 3 54 to 3 70 km s 1 along the profile and thus average crustal poisson s ratio varies from 0 23 beneath the central pamir in the south central part of the profile to 0 265 towards the northern end of the profile beneath the southern tien shan the main layer of the upper crust extending from about 2 km below the earth s surface to 27 km depth below sea level b s l has average p velocities of about 6 05 6 1 km s 1 except beneath the south central part of the profile where they decrease to around 5 95 km s 1 this is in contrast to the s velocities which range from 3 4 to 3 6 km s 1 and exhibit the highest values of 3 55 3 6 km s 1 where the p velocity is lowest thus for the main layer of the upper crust is 0 26 beneath the profile except beneath the south central part of the profile where it decreases to 0 22 the low value of 0 22 for under the central pamir the along strike equivalent of the qiangtang terrane in tibet is similar to that within the corresponding layer beneath the northern lhasa and southern qiangtang terranes in central tibet and is indicative of felsic rocks rich in quartz in the state the lower crust below 27 km b s l has p velocities ranging from 6 1 km s 1 at the top to 7 1 km s 1 at the base further for this layer is 0 27 0 28 towards the northern end of the profile but is low at about 0 24 beneath the central and southern parts of the profile which is similar to the situation found in the northeast tibetan plateau the low values can be explained by felsic schists and gneisses in the upper part of the lower crust transitioning to granulite facies and possibly also eclogite facies metapelites in the lower part within the uppermost mantle the average p velocity is about 8 10 8 15 km s 1 and is about 0 26 assuming an isotropic situation then a relatively cool 700 800 c uppermost mantle beneath the profile is indicated this would in turn indicate an intact mantle lid beneath the profile an upper mantle reflector dipping from 104 km b s l 120 km from the southern end of the profile to 86 km b s l 155 km from the northern end of the profile has also been identified the preferred model presented here for the crustal and lithospheric mantle structure beneath the pamir calls for nearly horizontal underthrusting of relatively cool indian mantle lithosphere the leading edge of which is outlined by the pamir seismic zone this cool indian mantle lithosphere is overlain by significantly shortening warm asian crust the moho trough that is a feature seen beneath some other orogenic belts for example the alps and the urals beneath the northern pamir may mark the southern tip of the actively underthrusting tien shan crust along the main pamir thrust

determining groundwater protection zones for the quaternary aquifer of northeastern nile delta using gis based vulnerability mapping the area of study lies at the northeastern part of nile delta global shoreline regression and sea level rise have their own bearing on the groundwater salinization due to seawater intrusion a new adopted approach for vulnerability mapping using the hydrochemical investigations geographic information system and a weighted multi criteria decision support system wmcdss was developed to determine the trend of groundwater contamination by seawater intrusion six thematic layers were digitally integrated and assigned different weights and rates these have been created to comprise the most decisive criteria used for the delineation of groundwater degradation due to seawater intrusion these criteria are represented by the total dissolved solids well discharge sodium adsorption ratio hydrochemical parameter cl hco3 hydraulic conductivity and water types the wmcdss modeling was tried where a groundwater vulnerability map with four classes ranging from very low to high vulnerability was gained the map pinpointed the promising localities for groundwater protection which are almost represented by the very low or low vulnerability areas 53 69 of the total study area the regions having high and moderate groundwater vulnerability occupy 46 31 of total study area which designate to a deteriorated territory of groundwater quality and needs special treatment and cropping pattern before use however the moderate groundwater vulnerability class occupies an area of about 28 77 of the total mapped area which highlighted the need for certain management practices to prevent the saltwater intrusion from expanding further to the south there was a good correlation of the constructed vulnerability map with the recently gathered water quality data and hydrochemical facies evolution the plotting of water quality data on piper trilinear diagram revealed the evolution of freshwater into the mixing and the saline zones as an impact of seawater intrusion which validates the model results

a comparative study of four schemes for groundwater vulnerability mapping in a diffuse flow carbonate aquifer under mediterranean climatic conditions this paper shows the results of a comparative study involving application of the vulnerability mapping methods known as avi god drastic and epik to a pilot carbonate massif in southern spain namely the torremolinos aquifer the main objectives of the study were to determine which methods are most suitable for diffuse flow carbonate aquifers such as in southern spain and to evaluate variations in the degree of vulnerability associated to the rainfall variations that normally occur in a mediterranean climate according to three of the above methods the aquifer is moderately vulnerable but the avi method evaluated it as highly vulnerable this however is improbable the vulnerability maps reflect the great importance of geology related parameters mainly those concerned with lithology and to a lesser degree that of the depth of the groundwater table which is related to the rainfall after this latter parameter it is possible to distinguish between humid and dry climatic situations thus vulnerability increases in a humid year especially according to the god and avi methods in conclusion the god method seems the most adequate of the methods applied in this work for vulnerability mapping of diffuse flow carbonate aquifers in the mediterranean domains

dynamics of slab detachment 1 we investigate the dynamics of slab detachment around the detachment zone and evaluate the amount of time necessary for slabs to detach the study combines results of two dimensional 2d state of the art thermomechanical numerical simulations and a 1d analytical solution for viscous necking under gravity we show that the dominant deformation mechanism during slab detachment is viscous necking independent of the depth of slab detachment when the slab dip is moderate 35 70 slab detachment is partly affected by localized simple shearing in the colder parts of the slab brittle fracturing breaking plays a minor role during slab detachment our 2d thermomechanical models indicate that the duration of slab detachment quantified from the onset of slab thinning until the actual detachment i e vanishing of slab pull force is relatively short 250 km can occur within a short time interval 1 ma which has implications for geodynamic interpretations using slab detachment as explanation for processes such as melting exhumation or surface uplift the thinning of the slab during detachment observed in 2d simulations agrees well with predictions from a 1d analytical solution indicating that the 1d solution captures the first order features of the detachment process we also evaluate the impact of shear heating on the duration of slab detachment the predictions of a simple semi analytical solution based on dimensionless parameters agree well with our and previously published results

application of geochemistry and radioactivity in the hydrogeological investigation of carbonate aquifers sierras blanca and mijas southern spain the chemical characteristics 3 h contents and radioactivity of groundwaters from the sierras blanca and mijas southern spain have been studied in relation to the chemical composition and radioactivity of the aquifer host rocks and the residence time of the water the sierras blanca and mijas are made up of calcitic and dolomitic marbles of triassic age the groundwaters that drain the calcitic marbles which outcrop principally in the western sierra blanca have less mineralization which descreases quickly with recharge as does the 3 h content and the gross alpha and beta activities are below detection limit this is due to the short residence time of water inside the aquifers which are conduit flow systems the waters of the dolomitic marbles eastern sierra blanca and sierra mijas have higher and less variable mineralization and contain greater concentrations of mg 2 sio2 and so 2 4 ions normally associated with slow flows the 3 h contents are more uniform with time indicating an older age and there is detectable natural radioactivity because the waters have a longer residence time in the aquifers which