holocene sea level changes in the indo pacific holocene sea level reconstructions exist from many locations in the indo pacific region despite being a large geographical region the nature of holocene sea level change is broadly similar in all locations differences do exist however in the timing and magnitude of the mid holocene high stand mhhs and the nature of late holocene sea level fall across the region when the indo pacific is subdivided into smaller regions these discrepancies do not disappear and in some cases the discrepancies are large within a single coastline it is clear from this analysis that the fundamental criteria to produce accurate local relative sea level curves are hardly ever met there are serious problems associated with the correct interpretation of sea level indicators and their relationship to mean sea level and with the quality of age determinations a consistent methodology throughout the indo pacific for the analysis of sea level data is lacking future sea level analysis from far field locations must involve the application of a consistent methodology in order to allow meaningful comparison between studies this should help to resolve the ongoing debate about the magnitude and timing of the mid holocene high stand and the nature of late holocene sea level fall across the region

tectonosedimentary evolution related to extreme crustal thinning ahead of a propagating ocean example of the western pyrenees 1 in this paper we describe the tectonosedimentary evolution and its subsequent inversion of a basin that underwent extreme crustal thinning in a transtensional setting ahead of a propagating ocean in the western pyrenees the labourd mauleon area situated in the western pyrenees at the termination of the v shaped bay of biscay is an ideal natural laboratory to study how such complex basins evolve in time and space because of a mild inversion of the basin during pyrenean compression the rift structures and their relations to basement rocks and sediments are exposed and can be directly studied in the field the basin shows a complex polyphase evolution that starts with left lateral dominated transtension in latest jurassic early aptian time this event is overprinted by a late aptian early albian extension that is related to the counterclockwise rotation of iberia away from europe leading to the opening of the bay of biscay during this stage the late triassic to jurassic carbonate platform was stretched salt migrated and detachment faults exhumed upper and lower crustal and mantle rocks to the seafloor the final structure of the basin resembles a sag basin floored by exhumed rocks overlain by extensional allochthons and compartmentalized by n40 to n60 transfer faults the sedimentary architecture is characterized by late aptian synrift sediments e g urgonian limestones that were deposited in fault bounded basins and are overlain by thick latest aptian to albo cenomanian sediments e g flysch noir that define a sag sequence the complex tectonosedimentary evolution of the basin is associated with salt tectonics and overprinted by a major magmatic thermal event that postdates mantle exhumation

the deep seismic reflection marconi 3 profile role of extensional mesozoic structure during the pyrenean contractional deformation at the eastern part of the bay of biscay abstract the new marconi 3 deep seismic profile allows recognition of the upper crustal structure of the eastern part of the bay of biscay and the main features of its alpine geodynamic evolution it denotes that the easternmost part of the bay of biscay consists of a thick wedge of uppermost cretaceous to cenozoic synorogenic sediments lying unconformably on the top of a thinned continental crust with the mesozoic parentis basin to the north and the coeval landes high to the south the parentis basin appears as a major half graben bounded southwards by a north dipping planar fault it is filled by a thick sequence of jurassic upper cretaceous carbonates affected by salt domes and squeezed diapirs made up of triassic evaporites and mudstones these salt tectonic structures also affect the overlying uppermost cretaceous to lower miocene synorogenic deposits which are folded upon these structures the landes high includes a thin pre upper cretaceous cover tilted to the south in the basque shelf it is deformed by a basement involving thrust wedge emplaced during the late eocene miocene that constitutes the north pyrenean contractional front geometric relationships and thickness variations depict that this overall structure results from the following mesozoic extensional stage which includes a late jurassic late aptian syn rift stage in which the parentis basin formed and an albian early late cretaceous post rift stage in which diapirs of triassic evaporites grew close to this major fault compressive deformational stage coeval to the pyrenean orogeny which led to 1 the development of a latest cretaceous up to middle miocene foreland basin and 2 from late eocene the formation of a basement involving thrust wedge in the innermost foreland basin the squeezing of the diapiric structures formed previously in the parentis basin and later middle miocene the partial inversion of some pre existent faults located in the southern parentis basin margin this geodynamic evolution together with the structure of the area evidences that the extensional structure resulting from the opening of the bay of biscay played an important role both in the location of the north pyrenean front and in the north pyrenean foreland contractional deformation features specially the lack of significant inversion structures in the parentis basin despite that it belongs to a severely thinned crustal area before the alpine compression denotes that the mesozoic landes high acted as an important buffer for the propagation of the pyrenean contractional deformation to the north this deformational buffer was active until early miocene and probably vanished afterwards during the last stages of pyrenean orogen development when some basement faults reactivated in the parentis basin

three dimensional gravity and magnetic modeling of crustal indentation and wedging in the western pyrenees cantabrian mountains 1 the complex crustal structure of the boundary zone between the iberian and european plates from the western pyrenees to the cantabrian mountains is probed by three dimensional 3 d gravity and magnetic modeling constrained by deep seismic profiles the 3 d modeling results support the presence of a continuous iberian crustal root and suggest that the geometry of the orogenic belt that formed in latest cretaceous tertiary times along the northern margin of iberia was conditioned by oblique structures separating areas characterized by different tectonic styles in the western pyrenees and the basque cantabrian basin a thick mesozoic basin presently incorporated to the pyrenean cantabrian belt the relatively narrow thinning of the crust inherited from the mesozoic rifting stage conditioned a structural style in which portions of the southward indenting european lower crust are interpreted to be back thrusted toward the north and uplifted to shallow depths promoting the appearance of significant potential field anomalies in the basque cantabrian basin the strongest aeromagnetic anomaly of the whole iberian mainland is superimposed on the eastern part of a well defined positive gravity anomaly similar in amplitude and wavelength to those located along the north pyrenean zone these observations suggest that the eastern part of the dense lower crustal causative body is strongly magnetized and may correspond to a gabbroic cumulate originated in the axis of the ancient mesozoic rift to the west tertiary compression affected the north iberian cantabrian passive continental margin whose geometry and inherited structures conditioned the formation of a double crustal delamination and the uplift of the cantabrian mountains

integrated two dimensional lithospheric conductivity modelling in the pyrenees using field scale and laboratory measurements abstract recent magnetotelluric mt studies have shown that the lower crust in the pyrenees contains a high conductivity zone consistent with a subducting continental slab whose conductivity is 0 33 s m partial melting has been interpreted to be the most plausible explanation for this high conductivity here we report a two dimensional conductivity model of the lithosphere by integrating field scale and laboratory determinations of the conductivity of continental crustal and mantle rocks the laboratory data provide empirical formulas which allow us to determine the fluid saturated rock and melt conductivity when temperature pressure and lithology are known consequently we have also calculated the density lithostatic pressure and several alternative temperature profiles for use in the model from gravity seismic and thermal field data these can be used with a prescribed melt fraction to predict the electrical conductivity at depth which can be compared with the mt conductivity data alternatively the laboratory data can be combined with the mt conductivity data to predict the melt fraction at depth the primary outputs of the modelling are conductivity and melt fraction prediction profiles for six mixing models i waff s model hashin shtrikman hs upper bound ii hs lower bound iii parallel layers iv perpendicular layers v random melt areas and vi a modified archie s law that takes account of the presence of two conducting phases the modelling results indicate that a good match to the mt data can be obtained along the whole profile by the influence of pressure temperature and the fluid phase with the only exception being the subducted slab where a minimum of 4 7 melt fraction is necessary to explain the data

the role of the bay of biscay mesozoic extensional structure in the configuration of the pyrenean orogen constraints from the marconi deep seismic reflection survey 1 seismic interpretation of the marconi deep seismic survey enables recognition of the upper crustal structure of the eastern part of the bay of biscay and the main features of its alpine geodynamic evolution the new data denotes that two domains with different pyrenean and north foreland structures exist in the bay of biscay in the eastern or basque parentis domain the north pyrenean front is located close to the spanish coast and the northern foreland of the pyrenees is constituted by a continental crust thinned by a north dipping fault that induced the formation of the early cretaceous parentis basin in the western or cantabrian domain the north pyrenean front is shifted to the north and deforms a narrower and deeper foreland basin which lies on the top of a transitional crust formed from the exhumation of lithospheric mantle along a south dipping extensional low angle fault during the early cretaceous the transition between these two domains corresponds to a soft transfer zone linking the shifted north pyrenean fronts and a north to wnw directed thrust that places the continental crust of the landes plateau over the transitional crust of the bay of biscay abyssal plain comparison between this structure and regional data enables characterization of the extensional rift system developed between iberia and eurasia during the late jurassic and cretaceous and recognizes that this rift system controlled not only the location and features of the pyrenean thrust sheets but also the overall structure of this orogen

seismic image of the cantabrian mountains in the western extension of the pyrenees from integrated escin reflection and refraction data abstract integrated analysis of normal incidence and large aperture seismic reflection data collected in 1992 and 1993 within the spanish escin and complementary projects provide a first complete n s crustal transect across the northern iberian peninsula and continental margin images of the crustal structure of the cantabrian mountains and their transition to the duero basin and to the cantabrian margin are obtained from a a 65 km long vertical reflection profile escin 2 on land b a 200 km long reversed refraction profile and c wide angle recordings of the marine escin 4 profile consistent results between reflectivity pattern and velocity depth distribution reveal important lateral variations in the deep structure the reflective crust imaged in the escin 2 profile changes its attitude from sub horizontal beneath the duero basin to north dipping beyond the mountain front basement thrusts are observed in the upper crust merging into a detachment at 6 s twt and may have triggered the alpine uplift of the range the moho is identified at the bottom of the reflective lower crust and deepens from 12 to 15 s at the northern end of the profile about 35 km inland modelling of the refraction data laterally extends the seismic image and provides evidence for variscan crustal features beneath the duero basin northwards the velocity in the lower crust decreases and the moho constrained by the wide angle data from profile escin 2 deepens to about 60 km ending abruptly at the shoreline the velocity depth model is constrained along the asturian platform up to the continental slope where the crust mantle boundary is located at 24 km depth this margin moho shows a progressive deepening southwards and extends to the coast where it is found at 30 km depth the present seismic data support an important alpine reworking and thickening of the crust under the cantabrian mountains the onshore offshore transition is marked by an imbrication of two crusts of very different thicknesses this signature offers a strong parallelism with the one previously observed further east across the pyrenees in the ecors seismic profile

joint inversion of marine magnetotelluric and gravity data incorporating seismic constraints preliminary results of sub basalt imaging off the faroe shelf breakup of the north atlantic during the early tertiary was accompanied by widespread and massive magmatism resulting in the coverage of large areas of the north atlantic with flood basalts these flood basalts hamper seismic investigations of underlying sequences and thus the understanding of the rifting subsidence and evolution of the margin which in turn increases the risk for hydrocarbon exploration in this paper we present a methodology for the simultaneous joint inversion of diverse geophysical datasets i e free air gravity and magnetotelluric soundings mt using seismic a priori constraints the attraction of the joint inversion approach is that different geophysical measurements are sensitive to different properties of the sub surface so through joint inversion we significantly reduce the null space and produce a single model that fits all datasets within a predefined tolerance using sensitivity analysis of synthetic data we show how each data set contains complementary important information of the supra and sub basalt structure while separate inversions of individual datasets fail to image through the basalt layer our joint inversion approach leads to a much improved sub basalt structure application of the joint inversion algorithm to satellite gravity data and mt data acquired on the flare10 seismic line south west of faroe islands supports the existence of a 1 km to 2 km thick low velocity region that might be indicative of the existence of a sedimentary basin underneath the basalt layer though in this paper we demonstrate the use of joint inversion on a sub basalt target we believe it has wider applicability to other areas where conventional seismic imaging fails

lithospheric characterization of the central pyrenees based on new magnetotelluric data terra nova 23 213 219 2011 abstract the pyrenees resulted from the continent continent collision between the iberian and european plates during the alpine orogeny although the subduction of the iberian lower crust is currently accepted the physical processes that occur at the boundary between the plates are still a topic of open discussion today as illustrated by the debate about the presence or absence of partial melting in the iberian subducted lower crust long period magnetotelluric data acquired for the first time in the central pyrenees constrain the low electrical resistivity structure in the iberian subducted lower crust better than previous studies plotting their upper limit 9 km deeper this new upper limit reinforces the hypothesis of partial melting additionally long period magnetotelluric data constrain the lithosphere asthenosphere boundary at 90 and 130 km deep below the iberian and european plates respectively and are compatible with electrical resistivity values between 10 and 18 ohm m for the asthenosphere

the anso transect of the southern pyrenees basement and cover thrust geometries a balanced geological section through the western central pyrenees allows the alpine geometry of hercynian basement to be determined this shows marked differences with other transects of the southern part of the chain basement involved thrust sheets do not form an antiformal stack but are imbricated and define steps separated by frontal culmination limbs basement thrusts propagate upwards and have formed distinct thrust systems in the cover in this transect the north pyrenean zone is bounded to the south by gently dipping thrusts of large displacement and the axial zone massif at its western termination area is a flat topped culmination caused by a single thrust fault the gavarnie thrust this thrust emerges to the south in the interior of the syntectonic jaca basin the geometry of which is also controlled by underlying basement thrusts various generations of structures can be correlated with distinct episodes of syntectonic sedimentation a sequential restoration of the section illustrates how successive foreland sedimentary wedges were generated and progressively involved in deformation tectonic shortening is 48 km almost half of that estimated further to the east for the southern pyrenees the structure deduced at the ecors pyrenees seismic section cannot be translated to this transect

new geoelectrical characterisation of a continental collision zone in the west central pyrenees constraints from long period and broadband magnetotellurics abstract continental collision dominates the development of a large number of mountain ranges on earth although the geological evolution of these regions is highly studied lithospheric scale physical processes are less well characterised and their interpretations frequently differ a new magnetotelluric profile crossing the west central pyrenees with broadband and long period magnetotelluric data constrains the geoelectrical features of this continental collision zone confining the geological and physical processes that take place at a lithospheric scale three geoelectrical structures associated with partial melting and its melt migration are imaged for the first time in the west central pyrenees suggesting an iberian subducted lower crust reaching the depth of 70 km this result supported by an analysis of the thermal evolution of the iberian subducted lower crust reinforces the hypothesis of partial melting in this region from the long period magnetotelluric data the asthenosphere has been imaged as a geoelectrical structure with electrical resistivity values between 20 m and 70 m the lithosphere asthenosphere boundary close to the collision zone has been constrained between 90 km and 110 km depth below the iberian plate and between 120 km and 160 km depth below the transition zone between plates and the european plate in agreement with the previous geophysical data additionally other geoelectrical anomalies imaged have been associated with an unexpected major variscan boundary located below the ebro basin silurian sediments and free fluids in the gavarnie thrust and with a thick sequence of jurassic and early cretaceous sediments situated below the north pyrenean thrust sheet

a new tomographic image of the pyrenean lithosphere from teleseismic data abstract a new tomographic model of the pyrenean lithosphere is determined down to 200 km depth from teleseismic p and pkp travel times with a lateral resolution of 0 25 compared to previous models two important improvements are 1 a larger number of stations with a more even distribution in particular to the west of the range and 2 the introduction before inversion of crustal corrections inferred from previous refraction and reflection experiments this last point is crucial because a strong moho jump up to 20 km is present at the north pyrenean fault the former boundary between eurasian and iberian plates the comparison of the models obtained with and without crustal corrections reveals the strong contamination of the models by the crust down to 100 km depth in the uncorrected model a large strip with negative p velocity anomalies previously interpreted as subduction of lower crust is observed it disappears in the corrected model moreover the introduction of crustal corrections allows us to reveal short wavelength heterogeneities which were hidden by the crustal signal an attempt is made to relate the heterogeneities revealed by the tomographic model with the tectonic history of the pyrenees in particular with the alpine orogeny the alpine phase includes an extensive episode with generation of the thin continental crust and possibly the opening of an oceanic sea floor and then a compressive stage in our model no signature of an oceanic subducted slab could be detected all along the range a result which rules out the opening of a large oceanic floor before the compressive stage a subduction of continental crust is possible but due to the transformation of lower crust into eclogite at depth it can not be detected by seismological methods whereas it was observed from electrical and gravity data to the east of the range large heterogeneities with low velocities are ascribable to the neogene extension related to the rotation of the corso sardo block and the opening of the gulf of lion a prominent high velocity anomaly extending down to 200 km in eastern central pyrenees could possibly be interpreted as a detached piece of the tethys slab in north of iberia outside the range deep down to 200 km low velocity structures oriented n130 e are probably related to hercynian orogeny

electromagnetic imaging of variscan crustal structures in sw iberia the role of interconnected graphite abstract the western part of the iberian peninsula iberian massif is the best exposed fragment of the variscan orogen in europe its southern half was generated by an oblique collision between three continental terranes belonging to the margins of laurassia avalonia the south portuguese zone spz and gondwana the ossa morena zone omz and the central iberian zone ciz the boundaries between them are considered to be suture zones a 200 km long magnetotelluric profile across the three variscan terranes was done in a nne direction approximately perpendicular to the main tectonic features the results of two dimensional inversion of the mt dataset reveal high conductivity zones coinciding with the transitions spz omz and omz ciz these conductive bodies related to the sutures at depth were interpreted as graphite enrichments along shear planes formed due to the overall transpressive regime a high conductivity layer extending along the whole omz was found at a depth of 15 25 km the top of which spatially correlates with a broad reflector detected by a recently acquired deep seismic reflection profile the high conductivity was interpreted as caused by the precambrian serie negra graphite rich rocks carbon and oxygen x ray mapping with electron microprobe on polished sections of serie negra samples from omz revealed the presence of interconnected graphite which supports the hypothesis that graphite is determinant for the high conductivity two graphite types which help to record the geological evolution were identified graphite accumulations in the schistosity surfaces produced by folding and metamorphism and metallic films of graphite developed along late faults the conductive layer shows blobs of higher conductivity suggesting macro anisotropy additional mylonitisation and shearing produced by thrusting at depth can be the origin of these zones of enhanced conductivity given that the detachment level is located within the serie negra several high resistivity features were found in the upper crust related to devonian and carboniferous successions and probably to some unexposed plutons in the spz and the palaeozoic series of omz plus some granitic intrusions in the ciz a high resistivity zone extending to the whole crust is correlated with extensive late variscan granite intrusions

seismic activity at the western pyrenean edge abstract the present day seismicity at the westernmost part of the pyrenean domain reported from permanent networks is of low to moderate magnitude however it is poorly constrained due to the scarce station coverage of the area we present new seismic data collected from a temporary network deployed there for 17 months that provides an enhanced image of the seismic activity and its tectonic implications our results delineate the westward continuity of the e w pyrenean band of seismicity through the variscan basque massifs along the leiza fault ending up at the hendaya fault this seismicity belt is distributed on a crustal scale dipping northward to almost 30 km depth other relevant seismic events located in the area can be related to the central segment of the pamplona fault and to different e w thrust structures

magnetotelluric signature of the western cantabrian mountains the magnetotelluric signature of the alpine part of the cantabrian mountains was investigated in a n s magnetotelluric profile from the duero basin to the cantabrian shoreline a two dimensional conductivity model was obtained from the joint inversion of tm te modes and the geomagnetic transfer functions a shallow conductor associated with the sediments of the duero basin and three north dipping conductors in the upper and middle crust were detected of the latter one is interpreted as the sole detachment of the cantabrian mountains whereas the others correlate with the cabuerniga and san vicente de la barquera faults this geometry suggests that the cantabrian mountains comprise uplifted variscan basement a comparison with a seismic reflection profile shows a good correlation between these conductors and seismic features the lower crust is characterised by high conductivities

the influence of partial melting on the electrical behavior of crustal rocks laboratory examinations model calculations and geological interpretations abstract the complex electrical impedance of a granulite has been determined over the frequency range 10 1 to 105 hz at temperatures between 600 and 1200 c at normal pressure and different oxygen fugacities in the stability field of magnetite the impedance spectroscopic is measurements are compared with the results of melting experiments performed under the same experimental conditions and with the same rock sample as the is measurements a strong increase in the electrical conductivity of about one and a half orders of magnitude is observed during partial melting this increase is explained by the formation of an interconnected network of melt the wetting of the grain surfaces starts slightly above the solidus however complete interconnection of the network is detected at higher temperatures 1070 c and hence higher melt fractions 10 vol this is explained by deviations from the equilibrium fabric of the partially molten sample with a modified brick layer model mblm the electrical conductivity is calculated as a function of the observed melt portion this model is valid if the melt forms a complete interconnected network at the grain boundaries the electrical conductivity at different temperatures was modeled using the results of the melting experiments and the mblm melt 10 s m with ea melt 1 ev solid 0 01 s m with ea solid 1 4 ev the results of the laboratory examinations were applied to different crustal regions where partially molten rocks are assumed to exist the same mblm is used to estimate the melt fraction that is necessary to explain the high conducting zones hczs observed in the crust beneath the andean orogen the pyrenees and the tibetan plateau at least 14 4 and 4 vol of interconnected melt are necessary to produce the observed conductivity respectively the actual amount of melt should be higher due to perturbation problems and melt trapped in pockets

constraints on the crustal structure of the internal variscan belt in sw europe a magnetotelluric transect along the eastern part of central iberian zone iberian massif 1 the iberian massif is the best exposed segment of the european variscan belt it includes relatively well preserved terranes that were accreted by transpression along time and resulted in a number of geotectonic units that formed part of the late paleozoic assembly of the pangaea supercontinent in sw iberia these units are the central iberian zone ciz ossa morena zone omz and the south portuguese zone spz a 210 km long ne sw magnetotelluric profile was carried out through the ciz from the omz ciz boundary toward the north reaching the tagus cenozoic basin data dimensionality analysis resulted in a suitable 2 d electrical resistivity structure allowing a 2 d inversion of the data set complementary available geophysical data deep seismic gravity and aeromagnetic and a comparison with a detailed geological cross section led us to constrain the interpretation of the 2 d electrical resistivity structure of the ciz crust the results show for the upper crust the existence of diverse conductive resistive bodies that correlate well with known geological features sedimentary basins faults granitic plutons mineralized systems a mild but steady conductive band is located along the middle and lower crust that is interpreted as a mafic granulite basement the upper section of this band connects with several elongated shallow conductors providing further evidence for the existence in the central iberian zone of a complex decollement system where the major faults are rooted such a crustal architecture is viewed as the northward continuation of the variscan large scale structures previously recognized in the southern sectors omz and spz

gravity anomaly map of the pyrenean region and a comparison of the deep geological structure of the western and eastern pyrenees abstract a gravity anomaly map based on over 13 000 observations accurately delineates the major features of the pyrenean region an extensive gravity anomaly low in the south of the region appears to result from crustal thickening associated with the pyrenean mountain building episode several large positive gravity anomalies are apparent in the north pyrenean zone in the centre and west of the mountain chain but are absent in the east the interpretation of a series of gravity anomaly profiles along the pyrenees has been controlled by existing geophysical data the interpretations confirm the cause of the southern gravity anomaly low as thickened iberian crust and demonstrate as shown by previous seismic investigations that the transition to much thinner european crust is quite abrupt the sources of the positive anomalies in the north pyrenean zone are bodies in the upper crust with densities too high to be explained in terms of crustal materials these are interpreted as segments of upper mantle that originated in transtensional n s separation across the north pyrenean fault and were emplaced at shallow levels by thrusting during pyrenean orogenesis this is the first time that evidence has been presented for the presence of such mantle bodies in the pyrenees it is suggested that their absence in the east is caused by less extension between iberia and europe in this region during the transform motion between them prior to orogenesis allowing only limited ascent of deep material the greater extension in the west would have allowed the ascent of upper mantle into the space between iberia and europe which would have been further elevated during the thrusting associated with pyrenean orogenesis

seismic evidence of alpine crustal thickening and wedging from the western pyrenees to the cantabrian mountains north iberia 1 the alpine collision between the iberian and european plates resulted in a complex crustal structure beneath the northern iberian peninsula as revealed from a new set of seismic refraction wide angle reflection profiles the study area is characterized by two major e w ranges the cantabrian mountains and the pyrenees which are relayed to the south by the iberian chain important variations in crustal thickness and velocity distribution are found in a 560 km long e w transect in contrast to the typical 30 to 32 km thick european variscan crust of the western end of the profile a continuous alpine crustal root is evidenced from the cantabrian mountains to the central pyrenees with a moho depth of 46 48 km locally rising to 40 km depth in between beneath the basque cantabrian basin another outstanding feature is the inferred presence of high velocities of 6 40 6 75 km s at midcrustal depths which can be associated with portions of a lower crustal wedge from the northern european domain indenting the southern iberian crust during the alpine stage of compression this indentation produces the delamination of the iberian crust with northward underthrusting of its lower half and the consequent crustal thickening the indenting wedge has a discontinuous presence along the longitudinal section as it was controlled and or affected by n s to ne sw structures further evidence of the northward subduction of the iberian plate is provided by another profile toward the aquitaine basin while a n s profile across the iberian chain reveals an alpine midcrustal thickening beneath this belt with moho depths of 42 km

hydrograph separation for karst watersheds using a two domain rainfall discharge model highly parameterized physically based models may be no more effective at simulating the relations between rainfall and outflow from karst watersheds than are simpler models here an antecedent rainfall and convolution model was used to separate a karst watershed hydrograph into two outflow components one originating from focused recharge in conduits and one originating from slow flow in a porous annex system in convolution parameters of a complex system are lumped together in the impulse response function irf which describes the response of the system to an impulse of effective precipitation two parametric functions in superposition approximate the two domain irf the outflow hydrograph can be separated into flow components by forward modeling with isolated irf components which provides an objective criterion for separation as an example the model was applied to a karst watershed in the madison aquifer south dakota usa simulation results indicate that this watershed is characterized by a flashy response to storms with a peak response time of 1 day but that 89 of the flow results from the slow flow domain with a peak response time of more than 1 year this long response time may be the result of perched areas that store water above the main water table simulation results indicated that some aspects of the system are stationary but that nonlinearities also exist

crustal structure and orogenic material budget in the west central pyrenees surface and subsurface data are combined to construct a crustal scale cross section of the western central pyrenees france and spain at the boundary between the european and iberian plates the position of moho reflections in the ecors arzacq reflection profile suggests a tectonic wedge of european crust and upper mantle had indented the iberian plate at lower crustal levels the european wedge is overlain by an upper iberian wedge thus constituting a double stacked wedge geometry the upper wedge was delaminated and deformed giving rise to the pyrenean orogenic prism manifested as a bivergent fan in upper crustal levels the underthrust lower iberian plate has been imaged to depths of 55 60 km but crustal budget considerations based on a palinspastic reconstruction require that this continental root subducted to depths up to 90 km total orogenic contraction calculated from surface structures is about 75 80 km which was accomplished between the latest cretaceous and the early miocene at an averaged rate of 1 2 mm yr consistent with these moderate values exhumation of the orogen is much less than in the more shortened eastern parts of the range paleozoic basement and preorogenic mesozoic rocks are little eroded and much of the exhumation involved cannibalization of early foreland basins which once covered the entire poorly emergent orogen at this transect this resulted in a continuous process of sediment recycling and coupled with a considerable lateral arrival of material a bulk negative erosion sedimentation budget