stacked p to s and s to p receiver functions determination of crustal thickness vp and vs the h v stacking method h stacking is a routine method for determining crustal thickness h and vp vs using p to s ps receiver functions in this paper we show that s to p sp receiver functions may also be used to determine crustal parameters sp provides independent information complementary to ps we develop a method called h v crustal thickness velocity stacking where ps and sp receiver functions are stacked to jointly determine seismic crustal parameters h vp and vs beneath a given seismic station we demonstrate the utility of the h v stacking method using data from seismic station hyb hyderabad on the dharwar craton we estimate a crustal thickness of 34 5 km vp 6 55 km s and vs 3 85 km s beneath the station in good agreement with previous results the strength of the h v method is that it requires no assumptions about elastic parameters and or additional processing or methodology

geology and structure of the continental margin off northern israel and the adjacent part of the levantine basin abstract the continental margin off northern israel and southern lebanon is characterized by a narrow coastal plain in places it is absent a narrow shelf a narrow slope which is incised by numerous submarine canyons and by a complex topography of the adjacent deep sea levantine platform detailed seismic reflection surveys have revealed the development of the area since the late miocene during the messinian when the level of the mediterranean sea dropped the present continental slope area was exposed eroded and covered by thinly scattered sediments in the deep basin evaporite bearing series accumulated reaching 1 km in thickness about 60 km offshore during the pliocene quaternary the area was covered by a fine clastic sequence up to 1 5 km thick that forms the present continental margin basinward gravitational slumping of these sediments over the messinian evaporites which acted as a lubricant resulted in a complex topography and many shore parallel rootless growth faults along the base of the continental slope and the adjacent deep sea young faults which are exposed in northern israel and extend seaward comprise the most important structural feature of the study area these faults were active during the pliocene and quaternary possibly also during the miocene the major nw trending young yagur carmel fault and e w trending rosh hanniqra fault extend to the base of the continental slope where they converge enclosing the complex western galilee graben the relief of the base of the pliocene quaternary sequence was affected by motions of these faults and of smaller faults inside the graben farther seaward a horst like block is developed along the extension of the carmel fault still farther basinward there is a group of diapiric ridges trending nw to e w they were formed by flowage of messinian evaporites in some cases these ridges seem to be aligned along underlying faults this group of diapirs is unique in the area the diapir ridges are interpreted as expressions of deeply rooted faults

crustal structure due to collisional and escape tectonics in the eastern alps region based on profiles alp01 and alp02 from the alp 2002 seismic experiment 1 alp01 and alp02 are the longest profiles recorded during alp 2002 a large international seismic refraction and wide angle reflection experiment undertaken in the eastern alps in 2002 alp01 crosses the alpine orogen from north to south thus providing a cross section mainly affected by the collision between europe and the adriatic microplate alp02 extends from the eastern alps to the pannonian basin supplying evidence on the relation between alpine crustal structure and tectonic escape to the pannonian basin during this experiment 363 single channel recorders were deployed along these profiles with an average spacing of 3 2 km recordings from 20 inline shots were used in this study two dimensional forward modeling using interactive ray tracing techniques produced detailed p wave velocity models that contain many features of tectonic significance along alp01 the european moho dips generally to the south and reaches a maximum depth of 47 km below the transition from the eastern to the southern alps the adriatic moho continues further south at a significantly shallower depth moho topography and a prominent south dipping mantle reflector in the alpine area support the idea of southward subduction of the european lithosphere below the adriatic microplate the most prominent tectonic feature on the alp02 profile is a vertical step of the moho at the transition between the alpine and pannonian domains suggesting the existence of a separate pannonian plate fragment the development of the pannonian fragment is interpreted to be a consequence of crustal thinning due to tectonic escape from the alpine collision area to the pannonian basin

lithospheric thickness under the dinarides abstract the nature of the interaction between adriatic and euroasian lithospheric plates in the dinarides is important for understanding the complex tectonic history of the central mediterranean using the data from permanent and temporary seismic stations in the wider dinaric region we imaged the lithospheric and upper mantle structure under this area specifically we focused on mapping the lithosphere asthenosphere boundary lab using the s receiver functions in order to establish boundaries between different tectonic domains present in this region the lithospheric thickness in the investigated area varies between 50 and 160 km with high degree of variability between adjacent tectonic realms below northwestern dinarides the lab depth varies between 100 and 120 km thinning towards adriatic sea and pannonian basin to 90 and 70 km respectively in the central dinaric region lika region we find anomalously thin lithosphere with thickness varying between 50 and 70 km and weak velocity gradient defining the lab further south the signal from the lab is more pronounced with lithosphere getting thicker again with average depths around 90 km the intriguing observation of thinned lithosphere under central part of the dinarides coincides with the zone of lower seismicity and with the tomographic images showing the slab gap in this area

the messinian event on the margin of the mediterranean sea in the nice area southern france abstract seismic reflection profiles have been used to map the messinian erosion surface and associated basin margin deposits on the continental margin off nice a palaeovalley extends seaward from the incised var palaeovalley mapped on land the lower part of this valley is filled by an acoustically incoherent unit with a flat top and steep slope into the basin this unit is interpreted as a coarse grained deltaic deposit that accumulated synchronously with the upper messinian evaporites in a ponded lake basin two submersible dives on strategic outcrops supported the interpretation of the seismic profiles we examined and sampled outcrops of probably early tertiary sandstones underlying the messinian erosion surface and of a fining up predominantly conglomeratic sequence that fills messinian channels on the continental slope and probably overlies the deltaic deposits these conglomerates pass up into early pliocene marls and have turbidite sedimentary structures these are prodeltaic deposits formed during the transgression at the end of the messinian based on seismic facies mapping sampling and submersible observations a palaeogeographic reconstruction of the area is proposed a basal erosion surface including the var palaeovalley represents extreme dessication of the western mediterranean and was followed by accumulation of the main messinian salt following this a lake was ponded in the ligurian basin with accumulation of evaporites and shales a gilbert type delta prograded into the basin from the var palaeovalley relative sea lake level lowering is estimated to be about 1200 m at this time there has been little faulting on the margin since the early pliocene transgression but there is estimated to have been about 800 m of flexural subsidence due to both thermal subsidence and water loading

eocene to present subduction of southern adria mantle lithosphere beneath the dinarides we modeled global positioning system measurements of crustal velocity along a n13 e profile across the southern adria microplate and south central dinarides mountain belt using a one dimensional elastic dislocation model we assumed a n77 w fault strike orthogonal to the average azimuth of the measured velocities but we used a constrained random search algorithm minimizing misfit to the velocities to determine all other parameters of the model the model fault plane reaches the surface seaward of mapped sw verging thrusts of eocene and perhaps neogene age along the coastal areas of southern dalmatia consistent with sw migrating deformation in an active fold and thrust belt p wave tomography shows a ne dipping high velocity slab to 160 km depth which reaches the surface as adria dips gently beneath the foreland and becomes steep beneath the dinarides topographic high the thrust plane is located directly above the shallowly dipping part of the slab the pattern of precisely located seismicity is broadly consistent with both the tomography and geodesy deeper earthquakes down to 70 km correlate spatially with the slab and shallower earthquakes are broadly clustered around the geodetically inferred thrust plane the model fault geometry and loading rate ages of subaerially exposed thrusts in the fold and thrust belt and the length of subducted slab are all consistent with adria eurasia collision involving uninterrupted subduction of southern adria mantle lithosphere beneath eurasia since eocene time

continental crust composition constrained by measurements of crustal poisson s ratio deciphering the geological evolution of the earth s continental crust requires knowledge of its bulk composition and global variability the main uncertainties are associated with the composition of the lower crust seismic measurements probe the elastic properties of the crust at depth from which composition can be inferred of particular note is poisson s ratio this elastic parameter can be determined uniquely from the ratio of p to s wave seismic velocity and provides a better diagnostic of crustal composition than either p or s wave velocity alone1 previous attempts to measure have been limited by difficulties in obtaining coincident p and s wave data sampling the entire crust2 here we report 76 new estimates of crustal spanning all of the continents except antarctica we find that on average increases with the age of the crust our results strongly support the presence of a mafic lower crust beneath cratons and suggest either a uniformitarian craton formation process involving delamination of the lower crust during continental collisions followed by magmatic underplating or a model in which crust formation processes have changed since the precambrian era

controls on the basinwide architecture of late miocene messinian evaporites on the levant margin eastern mediterranean abstract interpretation of 2d and 3d seismic data from the levant margin eastern mediterranean has revealed the complex depositional and structural setting of the basinwide late miocene messinian evaporites the data set covers a total area of 20 000 km2 permitting a semi regional investigation of the thick up to 1 8 km evaporitic wedge the sequential analysis of time structure maps isochron maps and seismic cross sections highlighted the main morphological and structural features characterizing the pre syn and post evaporitic levant margin this approach provided insights on the impact of local vs regional factors in governing the distribution of the messinian salinity crisis in the region two regional features have been recognized as the most significant controlling factors for the architecture of the messinian evaporites firstly a series of anticlines of the syrian arc foldbelt acted as a structural barrier indirectly governing the overall landward extension of the evaporites secondly submarine canyons active in the area at least since the oligocene afiq el arish and ashdod canyons represented preferential sites of erosion and deposition of evaporites our results document therefore the importance of the deep seated structures and relict drainage for the architecture of the messinian evaporites on the levant margin the new insights provided can be additionally used to infer the original depositional geometry of the evaporites in the study area and as an analogue in other mediterranean areas where 3d seismic is not available yet and sub salt imaging is limited

geological structure of the earth s crust above the moho discontinuity in yugoslavia summary the moho discontinuity was modelled on the basis of the 6 dss profiles across the yugoslav area by the use of regression analysis and expressed by fitting surfaces from the 1st up to the 4th degree their characteristics were correlated to the geological structure of the earth s crust with intention to point out their connection with the deformations of the moho discontinuity

gravity driven thin skinned extension above zechstein group evaporites in the western central north sea an application of computer aided section restoration techniques normal faulting and halokinesis have been important controls on the deposition and subsequent deformation of mesozoic and tertiary strata in the north sea in addition to the previously documented mechanisms of salt withdrawal dissolution and differential sedimentary loading it is recognized that gravity driven thin skinned extension above inclined salt layers has played an important part in north sea basin development commercial section restoration software has been used to facilitate depth conversion restoration and decompaction of seismic sections selected from an interpreted regional database in the western central north sea allowing validation of the interpretations and a graphical and highly quantitative description of salt assisted extension results of this work show that zechstein group evaporites were deposited in shallow sag basins during the permian triassic sedimentary pods were generated by localized deposition in synclinal basins and grabens above the evaporites bedded salt became folded while mobile salt flowed to fill anticline cores since the early jurassic regional tectonic tilting related to post rift subsidence and increasing sedimentary overburden have caused allochthonous mesozoic and tertiary strata to extend by gravity spreading above the mobile salt layer which detaches the allochthon from the underlying autochthonous late palaeozoic rocks concave up listric normal faults sole out in the salt layer propagate into the overlying cover sewuence and have been active at different geological times causing stratal thickening and folding within the allochthon antithetic and synthetic normal faults have developed producing complex upward branching fault systems in map view the listric faults form curvilinear en echelon arrays the faults linked by relay ramps fault blocks are typically 3 7 km wide 2 3 km thick and 7 10 km long salt movement during the jurassic tertiary has been driven by active extension of the cover causing salt to fill potential voids created by fault block rotation thus salt highs occur beneath sites of extension the listric faults generally dip in the same direction as the sub salt surface although there are also some major counter regional faults during extension regional dips have increased up to about 5 which is sufficient for gravity driven extension above a salt layer a total extension of about 6 has occurred the gravity driven thin skinned extension documented in the western central north sea is a phenomenon which can be recognized elsewhere in the north sea basin and can be readily compared with similar phenomena already documented in offshore angola brazil nova scotia and the gulf of mexico

tectonics and sequence stratigraphy in messinian basins sicily constraints on the initiation and termination of the mediterranean salinity crisis deposits within the caltanissetta basin of central sicily have been important for developing the desiccating deep basin model for the messinian salinity crisis in the mediterranean linked structural and stratigraphic studies show that the sicilian depocenters are synclines related to underlying thrust structures of the frontal part of the maghrebian chain prior to the salinity crisis these basins were hydrodynamically linked through the foredeep to the mediterranean the precursor sediments terravecchia formation formed a delta sourced from the north early messinian regression acted on a range of paleobathymetries shallow in the north and progressively deeper in the south locally complicated by active thrust structures initial draw down of mediterranean base level is marked across the thrust belt by first cycle carbonates and evaporites on the structural highs and lows respectively vast accumulations of halite and potassium salts up to 1200 m are restricted to growing thrust synclines the different evaporite signatures may be related to different water conditions reflecting various meteoric and marine circulations across various subbasins with cyclicity reflecting high frequency variations in sea level a sequence stratigraphic model is developed to explain fractionation of evaporite facies between different paleobathymetric settings and to predict the temporal evolution of the successions in different subbasins thrusting provides accommodation space for evaporites and also controls the water pathways into the desiccating basins the intra messinian unconformity separating first and second cycle evaporites is a type 1 sequence boundary related to the forced regression associated with the acme of mediterranean desiccation an interpretation supported by local ravinement and incised valley fills the overlying second cycle evaporites are a combination of detrital reworked first cycle material and primary gypsum formed under brackish water regional onlap relationships and bed continuity suggest that this water body was of regional extent with a systematically rising base level these interpretations have several implications for messinian correlations in the mediterranean the deep basin evaporites correlate with an intra messinian unconformity that separates the two cycles on sicily and postdate the first cycle deposits regional base level was largely restored before the end of the salinity crisis

tectonic and sedimentary conditions necessary for the deposition of the messinian evaporite successions in the eastern mediterranean a simple 2d model abstract the existing literature shows that the only saline water source for the eastern mediterranean during the messinian was the atlantic ocean and that the sicily sill created a physical barrier between the eastern and western mediterranean higher than the physical barrier at the gibraltar sill between the western mediterranean and the atlantic ocean the presence of distinctive messinian subunits in the eastern mediterranean similar to those observed in the western mediterranean suggests the existence of a similar set of depositional processes across the entire mediterranean during the messinian salinity crisis the above statements impose two critical conditions the eastern mediterranean massive salt deposits must be older than their counterparts in the western mediterranean and the sicily gateway must have remained within a goldilocks zone during the deposition of the massive eastern mediterranean evaporites predominantly halite while the sea level in the western mediterranean would remain at the level of the sicily sill a simple 2 d model is developed which satisfies these conditions the model suggests that the eastern and western basin margins experienced a nearly synchronized gypsum deposition associated with the initial drawdown of the mediterranean level followed by re sedimentation in the deep basins of the terrigenous and early evaporite deposits as the drawdown intensified the synchroneity of evaporite deposition across the eastern and western basins broke down as the sicily gateway became largely subaerial during a period when the calabrian arc area experienced uplift associated with slab break off the sicily sill must have remained within a goldilocks zone to allow the right amount of saline water inflow into the eastern mediterranean so that evaporites massive halite could be deposited during this time the sea level in the western mediterranean was at the breach level of the sicily sill and still open to atlantic water influx thus no evaporite deposition took place there the model suggests that further restriction of the inflow occurred across the gibraltar region which became largely subaerial associated with the uplift of the gibraltar arc caused again by lithospheric slab break off similar to the sicily gateway the gibraltar gateway also remained within the goldilocks zone to allow the right amount of saline water inflow into the western mediterranean so that massive halite could be deposited the re opening of the gibraltar gateway re flooded the western mediterranean first then the eastern mediterranean allowing the deposition of a mixed evaporite siliciclastic unit followed by the transgressive sediments with distinctive brackish water lago mare fauna

lateral extrusion in the eastern alps part 1 boundary conditions and experiments scaled for gravity lateral extrusion encompasses extensional collapse gravitational spreading away from a topographic high in an orogenic belt and tectonic escape plane strain horizontal motion of wedges driven by forces applied to their boundaries in the eastern alps it resulted from 1 an overall northerly compression apulia against eurasia 2 a strong foreland bohemian massif 3 lack of constraint along a lateral boundary carpathian region and 4 a previously thickened gravitationally unstable thermally weakened crust eastern alpine orogenic belt six indentation experiments reproduce lateral extrusion at lithospheric scale the models have two to four lithospheric layers with a mohr coulomb rheology for the upper and a viscous rheology for the lower crust the lithosphere rests upon a low viscosity asthenosphere a broad indenter a narrow deformable area and a weakly constrained eastern margin fullfill as closely as possible conditions in the eastern alps indentation produces both thickening in front of the indenter and escape of triangular wedges lateral variations in crustal thickness become attenuated by gravitational spreading the overall fault pattern includes domains of reverse strike slip oblique normal and pure normal faults strike slip faults in conjugate sets develop serially the narrow width of the deformable area and the strength of the foreland determine the angles between the sets gravitational spreading produces a rhombohedral pattern of oblique and pure normal faults along the unconstrained margin opposite the unconstrained margin the indenter front shows thrusts and folds intersecting with the conjugate strike slip sets a triangular indenter favors spreading high velocity of indentation favors escape high confinement limits lateral motion inhibits spreading and favors thickening lateral extrusion in the eastern alps is best modeled by 1 a weak lateral confinement 2 a broad and straight indenter 3 a narrow width of the deformable area and 4 a rigid foreland crustal thickening lateral escape and gravitational spreading all contribute to the overall deformation

geodynamic evolution of the northern dinarides and the southern part of the pannonian basin abstract most of the recent geodynamic interpretations of the pannonian basin focus on its relation to the formation of the carpathians and the alpine orogeny however also the dinarides were severely affected by neogene tectonics related to the formation of the pannonian basin especially in the northernmost dinarides neogene deformation played a very important role in the evolution of this mountain chain geological records clearly show evidence of two phases of plate convergence along the northern and eastern margins of the present day dinarides at the end of the jurassic the dinaridic parts of the tethys ophiolites were obducted onto the northeastern margins of the apulian microplate the second phase is documented in the central part of the northernmost dinarides it is genetically related to an ancient volcanic arc as indicated by late cretaceous palaeogene trench sediments with blueschist olistolithes which are interlayered by basalt rhyolites pyroclastics medium pressure metamorphosed trench sediments and associated synkinematic granitoids in the northern part of the dinarides subduction processes terminated with the eocene compressional event which caused the uplift of the dinarides numerous intramontane basins with shallow marine fluviatile and lacustrine deposits were generated during the oligocene penecontemporaneous andesites which are found along the drava and sava depressions of the south pannonian neogene basin can be correlated with the easternmost periadriatic tonalites however observations do not indicate strike slip faulting at that time in this area the neogene rift stage initiated the evolution of the pannonian basin it is marked by extruded submarine trachyandesites of karpathian age badenian basalts andesites dacites and rhyolites and pannonian alkali basalts which are interlayered by coeval sedimentary rocks main evidence for the large scale tectonic transport of large dinaridic blocks into the pannonian basin area are the periadriatic sava and zagreb zemplen fault systems and subparallel faults the late sarmatian global sea level drop which coincided with a compressional phase is regionally marked by an unconformity throughout the pannonian basin as reported by horvath horvath f 1995 phases of compression during the evolution of the pannonian basin and its bearing on hydrocarbon exploration mar pet geol 12 8 837 844 due to thermal subsidence during the pliocene more than 2000 m of lacustrine freshwater sediments were deposited in the south pannonian basin the pliocene compression phase can be observed in the transdanubian zone and also south of the mura and drava rivers by south and southwest dipping reverse fault systems

resedimentation of basin centre sulphate deposits middle miocene badenian of carpathian foredeep southern poland abstract the middle badenian anhydrite sections in the central part of the carpathian foredeep consist mainly of interbedded laminated anhydrite and anhydrite breccia these facies display features characteristic of redeposited sediments such as distortions due to slumping erosional boundaries and graded bedded laminae lamination in laminated anhydrite is rarely regular and often accompanied by disruptions the predominance of clasts of laminated anhydrite combined with the observed brecciation of laminated anhydrite indicates that a short distance for transport and even in situ reworking were common a high degree of convolution indicates that some reworked sediments were unconsolidated when they moved but in many cases they were probably at least partly lithified this is evidenced by the anhydrite breccia consisting of clasts of laminated anhydrite as well as the brecciation in situ the resedimentation processes have not been related to regional bathymetrical differences as indicated by minor differences along seismic profiles a great deal of redeposition within the basin centre of the middle badenian evaporite basin combined with the in situ brecciation suggests that the triggering mechanism for redeposition could be earthquakes they generated mass flows and eventually turbidites so that earlier deposited grains could be redeposited this implies that in other evaporite basins the laminar facies might be at least partly related to redeposition and not necessarily to changes of surface brine concentration as usually supposed

sequence stratigraphy of miocene pliocene carbonate siliciclastic shelf deposits in the eastern mediterranean margin israel effects of eustasy and tectonics abstract mio pliocene marine sediments comprise a discontinuous succession of carbonates and mixed carbonate siliciclastics on the neogene shelf which coincides with the judean foothills area on the slope present mediterranean coastal plain the succession forms a wedge up to 1500 m thick of mostly fine grained siliciclastics the facies and architecture of the succession were influenced both by sea level fluctuation and by the geodynamic change from thermally subsiding passive margins of the arabo african plate to a complex pattern of vertical movements that were associated with the breakup of the plate along the red sea rift and dead sea transform and the convergence of the african arabian and eurasian plates the miocene eustatic succession is highly interrupted by vertical uplift tectonics while the pliocene eustatic succession is well represented despite the limited subsidence rates during most of the early and middle miocene the shelf was tectonically uplifted above sea level except for a short period of flooding in early middle miocene times n8 n9 when sea level rise outstripped the uplift trend and a carbonate platform formed the combination of tectonic uplift and sea level fall prior to late miocene times about 11 m y ago resulted in the incision of a deep beer sheva canyon about 280 m below the shelf plane late miocene sandy marlstones of the bet eshel cycle filled the beer sheva canyon and spilled over it they display a shallowing upward trend resulting in progradational clinoform stacking of the highstand systems tract and channelled debris flows of the forced regression systems tract the messinian desiccation event left the shelf emerged while depositing evaporites on the slope and in the basin the degree of erosion during the messinian was relatively minor because of arid conditions and limited runoff the pliocene shelf shows a very low subsidence rate and compared to the miocene succession is less affected by vertical uplifts the pliocene deposits are divided into six sequences their relative onlap curve largely corresponds to the sequence stratigraphic scheme in sicily and the gulf of mexico the two lowermost sequences i and ii are composed of two sandy units the lower forms an incised valley fill of shoreface deposits in the beer sheva area and offshore sand deposits in distal shelf areas besor although largely eroded sequences i and ii display maximum coastal onlap of all pliocene cycles in the beer sheva canyon area sequence iii consists of mixed carbonate siliciclastic grainstones of shoreface foreshore deposits in the proximal area and lower shoreface deposits in more distal areas sequences iv and v may be considered as a single 3rd order cycle where iv represents regressive lowstand shale and sand deposits and v represents prograding highstand sandy grainstone deposits sequence vi consists of marginal marine to coastal plain marlstones and sands deposits and is largely truncated by the ahuzam conglomerate representing a major uplift phase of latest pliocene to early pleistocene age and marking the permanent emergence of the shelf

towards a mechanical model for the formation of the pannonian basin abstract new maps showing crustal and lithospheric thickness variations in the pannonian basin and the surrounding east alpine carpathian and dinaric mountains have been prepared on the basis of recent seismic seismologic and electromagnetic data a map presenting miocene faults of regional significance has been also constructed for the same region by using a wealth of recently available national and or more local studies it is suggested that observed crustal and lithospheric structural contrasts have been controlled primarily by neogene kinematic history of the region kinematic history is characterized by the following main patterns 1 1 indentation by adria and large scale backthrusting in the southern alps 2 2 eastward escape and extension of the eastern alps 3 3 extensional collapse in the pannonian basin area 4 4 formation of broad wrench fault systems along strike in the dinarides and southern carpathians and the western carpathians with dextral and sinistral shear respectively 5 5 compression and accretion of the external thrust and fold belt in the eastern carpathians these kinematic patterns are thought to be interrelated and all are manifestations of the late stage evolution of an overthickened orogenic wedge in order to arrive at a better understanding of the mechanism of extension which formed the pannonian basin deep crustal seismic profiles hydrocarbon exploration reflection lines and borehole data have been analyzed in the little hungarian plain this plain represents the transition zone between the alps and the pannonian lowlands and the results are illustrated by eight interpreted cross sections one result of regional importance is the clear recognition that the transdanubian central range at the southeastern flank of the little hungarian plain is composed of alpine pre senonian thrust sheets this finding marks the end of a century of debate the allochthony of the substrata of the pannonian basin can be now considered proven another result of more general interest is that these cross sections document the mode of lithospheric extension preexisting compressional detachment planes reactivate as low angle normal faults and lead to tectonic unroofing of deeply buried metamorphic terranes characterized by ductile flow along subhorizontal lineation

sedimentary and tectonic evolution of the vena del gesso basin northern apennines italy implications for the onset of the messinian salinity crisis the integration of field and subsurface data permits a substantial revision of the sedimentary evolution of the vena del gesso basin a thrust top basin in the northern apennines where shallow water primary gypsum deposits related to the messinian salinity crisis were well developed and preserved as inferred from lateral and vertical facies changes within the underlying deep marine turbidites of the marnoso arenacea formation evaporite precipitation occurred in a basin bounded to the north and to the east by a thrust related anticline actively growing since the late tortonian both gypsum deposition and subsequent deformation were strongly controlled by evolving paleobathymetry driven by tectonics primary gypsum precipitated in a shallow silled basin while in the adjacent deeper and larger foredeep basin organic rich shales were deposited gypsum deposits underwent severe postdepositional deformation related to large scale gravitational collapse as a result of a regional uplift event also coincident with the end of the evaporitic phase along the inner shallower dipping limb of the anticline bounding the basin large scale poorly deformed gypsum slabs moved downslope along a detachment surface developed at the contact with the underlying euxinic shales forming both extensional and compressional features and showing an overall southwestern vergence the identification of a south southwest dipping paleoslope here pointed out for the first time suggests that the deformational features affecting the gypsum unit were probably driven by gravity and not by active thrusting as thought up to now the steeper frontal limb of the anticline promoted the transformation of gypsum slides into debris flows and turbidite currents that deposited their load in the adjacent deeper basin this gravitational deformation was sealed by postevaporitic upper messinian lagomare deposits the sedimentary history of the vena del gesso basin suggests that the messinian salinity crisis in the apennine foredeep as well as in the balearic tyrrhenian sicily and eastern mediterranean basins was tightly linked to tectonic processes the large scale postdepositional collapse of primary evaporitic deposits is a widespread feature in the mediterranean basins and it may have altered the original stratigraphic relationships in some places this finding has potentially important implications for a correct paleoenvironmental reconstruction of the onset of the messinian salinity crisis

p wave tomography of the mantle under the alpine mediterranean area 1 we study the upper mantle p wave velocity structure below the euro mediterranean area down to 1000 km depth by seismic travel time tomography we invert summary residuals constructed with both regional and teleseismic first arrival data reported by the international seismological centre isc 1964 1995 introducing some alternative strategies in the travel time tomographic approach and a new scheme to correct teleseismic data for global mantle structure our high resolution model pm0 5 is parameterized with three dimensional 3 d linear splines on a grid of nodes with 0 5 spacing in both horizontal directions and 50 km vertical spacing we obtain about 26 root mean square rms reduction of residuals by inversion in addition to roughly 31 reduction after summary rays formation and selection sensitivity analyses are performed through several test inversions to explore the resolution characteristics of the model at different spatial scales the distribution of large scale fast anomalies suggests that two different stages of a convection process presently coexist in very close regions the mantle dynamics of western central europe is dominated by blockage of subducted slabs at the 660 km discontinuity and ponding of seismically fast material in the transition zone contrarily in the eastern mediterranean fast velocity material sinks into the lower mantle suggesting that the flow of the cold downwelling here is not blocked by the 660 km discontinuity on a smaller scale the existence of tears in the subducted slab lithospheric detachment all along both margins of the adriatic plate as proposed by some authors is not supported by our tomographic images

the interplay between subduction and lateral extrusion a case study for the european eastern alps based on analogue models a series of analogue experiments simulating intra continental subduction contemporaneous with lateral extrusion of the upper plate are performed to study the interference between these two processes at crustal levels and in the lithospheric mantle the models demonstrate that intra continental subduction and coeval lateral extrusion of the upper plate are compatible processes leading to similar deformation structures within the extruding region as compared to the classical setup lithosphere scale indentation strong coupling across the subduction boundary allows for the transfer of stresses to the upper plate where strain regimes are characterized by crustal thickening near a confined margin and dominated by lateral displacement of material near a weak lateral confinement the strain regimes propagate laterally during ongoing convergence creating an area of overlap characterized by transpression when subduction is oblique to the convergence direction the upper plate is less deformed and as a consequence the amount of lateral extrusion decreases in addition strain is partitioned along the oblique plate boundary resulting in less subduction in expense of right lateral displacement close to the weak lateral confinement both oblique and orthogonal subduction models have a strong resemblance to lateral extrusion tectonics of the eastern alps europe where subduction of the adjacent adriatic plate beneath the eastern alps is debated our results imply that subduction of adria is a valid mechanisms to induce extrusion type deformation within the eastern alps lithosphere furthermore our findings suggest that the oligocene to late miocene structural evolution of the eastern alps reflects a phase of oblique subduction followed by a later stage of orthogonal subduction conform a miocene shift in the plate motion of adria oblique subduction also provides a viable mechanism to explain the rapid decrease in slab length of the adriatic plate beneath the eastern alps towards the pannonian basin

reconstructing the alps carpathians dinarides as a key to understanding switches in subduction polarity slab gaps and surface motion palinspastic map reconstructions and plate motion studies reveal that switches in subduction polarity and the opening of slab gaps beneath the alps and dinarides were triggered by slab tearing and involved widespread intracrustal and crust mantle decoupling during adria europe collision in particular the switch from south directed european subduction to north directed wrong way adriatic subduction beneath the eastern alps was preconditioned by two slab tearing events that were continuous in cenozoic time 1 late eocene to early oligocene rupturing of the oppositely dipping european and adriatic slabs these ruptures nucleated along a trench trench transfer fault connecting the alps and dinarides 2 oligocene to miocene steepening and tearing of the remaining european slab under the eastern alps and western carpathians while subduction of european lithosphere continued beneath the western and central alps following the first event post late eocene nw motion of the adriatic plate with respect to europe opened a gap along the alps dinarides transfer fault which was filled with upwelling asthenosphere the resulting thermal erosion of the lithosphere led to the present slab gap beneath the northern dinarides this upwelling also weakened the upper plate of the easternmost part of the alpine orogen and induced widespread crust mantle decoupling thus facilitating pannonian extension and roll back subduction of the carpathian oceanic embayment the second slab tearing event triggered uplift and peneplainization in the eastern alps while opening a second slab gap still present between the eastern and central alps that was partly filled by northward counterclockwise subduction of previously unsubducted adriatic continental lithosphere in miocene time adriatic subduction thus jumped westward from the dinarides into the heart of the alpine orogen where northward indentation and wedging of adriatic crust led to rapid exhumation and orogen parallel escape of decoupled eastern alpine crust toward the pannonian basin the plate reconstructions presented here suggest that miocene subduction and indentation of adriatic lithosphere in the eastern alps were driven primarily by the northward push of the african plate and possibly enhanced by neutral buoyancy of the slab itself which included dense lower crust of the adriatic continental margin

crustal and uppermost mantle structure beneath the external dinarides croatia determined from teleseismic receiver functions summary broad band seismograms of teleseismic events recorded at the croatian seismological network were used to compute radial receiver functions rfs for eight locations in the external dinarides waveform modelling was performed by a multistep matching of the theoretical rfs computed for horizontally layered 1 d isotropic models with the averaged observed rfs constraints from existing deep seismic sounding profiles traveltime curves of regional crustal seismic phases and intuitive inferences gained from interactive forward modelling were used to construct initial 1 d models of the earth a non linear inversion was performed in two steps a grid search followed by the monte carlo search for the model parameters concurrently rfs from different azimuths were stacked to obtain trade off estimates of crustal thickness versus vp vs ratios the moho depths were found in the range from around 40 km for northern adriatic stations to over 55 km for stations in the central part of the external dinarides comparing our results with recent maps of the moho topography inferred from seismic and gravimetric data we find that for some stations the agreement between our results and the existing moho maps is very good for the others we find the mohorovicic discontinuity to be considerably deeper indicating some of the thickest crust in europe although it is plausible that such a deep moho could be a consequence of a complex tectonic setting of the region e g overlapping of two large tectonic units the adriatic microplate and the dinarides this result will have to be verified in the future studies using various other geophysical techniques

shallow and deep lithosphere slabs beneath the dinarides from teleseismic tomography as the result of the adriatic lithosphere downwelling abstract the study area covers the dinarides and southwestern part of the pannonian basin as the marginal zone between the adriatic microplate african plate and the pannonian tectonic segment eurasian plate we created a three dimensional seismic velocity model to 450 km depth using teleseismic tomography our travel time dataset was collected by means of 40 seismic stations from the orfeus database and croatian seismological survey database a set of 90 teleseismic earthquakes were selected in the time range 2014 2015 and relative p wave travel time residuals were calculated for the first time the seismic p wave velocity model of a relatively high resolution on the entire dinaridic mountain belt was obtained based on this model a more reliable insight in the relations of the lithosphere plates has been achieved we imaged a fast velocity anomaly extending underneath the entire dinaridic mountain belt which indicates cold rigid materials the anomaly is steeply sloping towards the northeast and directly indicates the sinking of the adriatic microplate underneath the pannonian tectonic segment in the northern dinarides the anomaly extends to the depth of 250 km whereas in the southern dinarides it covers greater depths up to 450 km the shallow adriatic slab extends along the external dinarides while the deep adriatic slab extends beneath the internal dinarides and ophiolite zones in the area of central and southern dinarides different slab depths are interpreted as the faster convergence of the plate in the southern dinarides than in the northern or the convergence of the plates had started in the southern part and systematically developed to the north

aragonian stratigraphy reconsidered and a re evaluation of the middle miocene mammal biochronology in europe abstract the recently collected fauna of armantes 1a in chron c5br of the armantes section necessitates reinterpretation of the previous bio and magnetostratigraphical correlations between the armantes and vargas sections calatayud daroca basin central spain w krijgsman m garces c g langereis r daams j van dam a j van der meulen j agusti l cabrera a new chronology for the middle to late miocene continental record in spain earth planet sci lett 142 1996 367 380 the long reversal in the vargas section is now correlated to c5br instead of to c5cr on the basis of the biostratigraphical correlation of armantes 1a to the faunas of fuente sierra 2 and 3 in the vargas section which are situated in the basal part of the middle aragonian mn5 this leads to the revised age of 16 0 ma for the early middle aragonian mn 4 5 boundary our age estimate of the mn5 6 boundary is maintained at ca 13 75 ma the vargas section is now considered to start in chron c5cn 2r and to end in c5bn 1n as a result of the revised correlation the duration of the time gap between the fossiliferous parts of vargas and the younger aragon section previously estimated as ca 1 5 myr is now reduced to less than 200 000 years the tie points of the european mammal units mn4 mn6 to the geomagnetic polarity time scale f f steininger w a berggren d v kent r l bernor s sen j agusti circum mediterranean neogene miocene and pliocene marine continental chronologic correlations of european mammal units in r l bernor v fahlbusch h w mittmann eds the evolution of western eurasian neogene mammal faunas columbia univ press new york 1996 pp 7 46 are evaluated our age estimates of the mn4 5 and mn5 6 boundaries are compatible with the new magnetostratigraphic calibration of middle miocene mammal zones in the swiss molasse basin o kempf t bolliger d kalin b engesser a matter new magnetostratigraphic calibration of early to middle miocene mammal biozones of the north alpine foreland basin in j p aguilar s legendre j michaux eds actes du congres biochrom 97 mem trav e p h e 21 1997 547 562

moho depth and poisson s ratio in the western central alps from receiver functions summary current knowledge about deep crustal structure of the alpine orogen has mainly been derived from p wave velocity models obtained from active and passive seismic experiments a complementary s wave model to provide lithological constraints necessary for unique structural interpretation has been missing to date in this paper we present important new information on s wave velocity model in the alps we applied the receiver function method using 6 yr of high quality data from 61 permanent and temporary stations sampling the western central alps we determined first order crustal features moho depth h and average vp vs ratio with the h stacking technique that uses timing of direct and multiple p to s converted phases from the moho interface synthetic tests reveal a dipping moho interface expected beneath an orogen causes a systematic bias of h and potentially leading to misinterpretation we thus applied corrections determined from synthetic data to remove the bias providing better fit of recovered moho depths with active seismic estimates for each site we also obtained independent h and estimates based on the timing of the strong ps phase our results show a gently south southeast dipping european moho at a depth of 24 30 km beneath the northern alpine foreland steepening rapidly towards the europe africa suture zone to reach a maximum depth of 55 km south of the suture the moho of the adriatic crust promontory of the african plate is at 35 45 km depth in the previously ill constrained western alps we found the european moho at 30 km depth beneath the more external units dipping east northeast to reach 50 55 km in the inner core of the alps the poisson s ratio clearly correlates with the tectonic units that comprise the alps average crustal values in the european alpine foreland are close to 0 25 in the alps we observe low values 0 22 in the highly deformed nappes of the mesozoic helvetic and southern alps indicating a thickening of felsic upper crustal material in contrast the poisson s ratio is significantly higher 0 26 in the penninic and austroalpine units near the suture zone this rapid and significant change marks a clear rupture between the alpine forelands and the suture domain we assign this high poisson s ratio to doubling of mafic lower crust consistent with results from previous active seismic experiments a continuation of the lower crustal wedge into the central part of the western alps however seems unlikely based on low observed poisson s ratios

revision of the earthquake catalogue and seismicity of croatia 1908 1992 the paper presents the results of croatian earthquake catalogue revision for the period 1908 1992 the revised catalogue lists a total of 4853 events 4486 after 1908 of which 3700 are mainshocks all primary data sources available to us seismograms phase onset time readings macroseismic questionnaires were consulted in order to improve the quality and reliability of magnitude intensity and location along with the most important earthquake parameters the catalogue contains entries that enable assessment of the reliability of location and bibliographic references using the temporal analysis of the maximum likelihood estimate of the b value in the frequency magnitude relation the catalogue is estimated to be complete for events with m 4 0 throughout the investigated period the magnitude completeness threshold decreases to 3 8 after the middle of the century and to about 3 6 in the last three decades it is noted that the b value variation with time is closely tied to the seismic activity as well as that at present there seems to be a lack of seismic energy release corresponding to the m 6 0 6 5 earthquake

structure of the european upper mantle revealed by adjoint tomography the structure of the european crust and upper mantle is precisely known only in limited regions a new tomographic model for the entire european upper mantle identifies northeastward subduction of the adria plate beneath the dinarides mountains volcanism related to the upwelling eifel hotspot and mantle delamination beneath scandinavia

fault controlled evaporite deformation in the levant basin eastern mediterranean abstract during the messinian salinity crisis a multi layered salt giant of 1 5 km thickness was precipitated in the levant basin easternmost mediterranean sea incipient deformation of this geologically young salt layer was commonly explained by gravity driven processes only based on high quality depth migrated seismic data we show for the first time how sub salt extensional faults influence the internal deformation pattern of the messinian evaporites in the levant basin extensional faulting started in the middle miocene and lasted until late messinian times we suggest faulting to have caused the development of fault propagation folds within the evaporite unit subsequently folds may have accommodated tectonic shortening at the latakia ridge and evolved into the presently observed complex intra evaporite fold pattern while fault controlled evaporite deformation is evident in the northern part of the levant basin only evaporites are increasingly influenced by nile derived differential sediment loading towards the south locally zones of reduced amplitudes in the sub salt domain terminate into phase reversed bright spots within the lower part of the evaporites indicating active fluid migration and potentially evaporite dissolution finally we present a high resolution velocity model of the messinian evaporites based on model based processing and residual moveout analysis relatively high interval velocities of acoustically transparent evaporites 3850 4240 km s are consistent with halite whereas lower velocities of reflective layers 3650 4030 km s may point towards the presence of low velocity evaporite facies like gypsum

body wave velocities in the circum adriatic region abstract the paper presents body wave velocities in the crust and upper mantle of the circum adriatic region obtained by analyzing travel times of regional phases of 419 selected earthquakes with epicenters in the central part of the external dinarides the studied region was divided into five areas and two kinds of velocity models were determined for each of them the first kind inter area models gives average velocities that characterize the zone between and including the epicentral region and the area in question while the second kind intra area models presents velocities within the respective area the locations of hypocenters considerably improved when the new models were used instead of the standard one for the balkan region the large scale variation of average velocities obtained by inter area modeling was found to be relatively small both in the crust and in the upper mantle on the other hand the magnitude and distribution of station corrections and the resulting intra area velocities point to relatively pronounced lateral velocity variation within some of the studied regions the obtained velocities in most cases do not differ significantly when compared to the values reported in other studies the most important exceptions occur in the epicentral area central part of the external dinarides where the p wave velocity in the upper crust is much higher then elsewhere while the velocity in the upper mantle is found to be lower than that determined by dss experiments there is also an indication of pronounced variation of the poisson ratio in this area

messinian subaerial erosion of the proto nile delta abstract the evaporitic drawdown and subsequent dessication of the mediterranean basins during the messinian salinity crisis has been confirmed by detailed seismic mapping of the ensuing erosion surface in the nile delta region the basal messinian unconformity determined by seismic analysis and borehole correlation extends from almost sea level in the southern delta area to depths of at least 5 km in the nile cone the onlap of the contemporaneously deposited fluvio deltaic clastics of the qawasim formation occurs at between 2 5 to 4 km below present gradual initial drawdown of the mediterranean sea with occasional sudden sporadic falls is implied by the presence of entrenched meanders and impaired rejuvenation terraces in the nile canyon formed as the proto nile river cut down into the pre existing tortonian delta complex the former tortonian delta slope became an extensive linear erosional front with over 3 km of vertical relief the uppermost levels of which were protected by tabular oligocene basalt flows preserved as mesas and buttes the lower slopes were the site of coalescing piedmont fans fed by upper slope wadi systems the piedmonts merged into the qawasim fluvio deltaic deposits of the proto nile fluvial flood plain the subcrop beneath the basal messinian unconformity reveals a remarkable diversity of rock type each with its own distinctive control on the geomorphology and geometry of the ensuing messinian erosional surface fracture patterns within the oligocene basalts produced a trellis drainage network which became later captured by a dendritic system developed on less resistant prodelta shales of the former tortonian delta slope close study of seismic profiles clearly demonstrates that the basal messinian erosional disconformity can be traced northwards to depths of at least 2 5 3 0 km before becoming affected by later pliocene faulting this validates a deep dessication model for the evolution of the messinian evaporites

chronology causes and progression of the messinian salinity crisis the messinian salinity crisis is widely regarded as one of the most dramatic episodes of oceanic change of the past 20 or so million years 1 3 earliest explanations were that extremely thick evaporites were deposited in a deep and desiccated mediterranean basin that had been repeatedly isolated from the atlantic ocean1 2 but elucidation of the causes of the isolation whether driven largely by glacio eustatic or tectonic processes have been hampered by the absence of an accurate time frame here we present an astronomically calibrated chronology for the mediterranean messinian age based on an integrated high resolution stratigraphy and tuning of sedimentary cycle patterns to variations in the earth s orbital parameters we show that the onset of the messinian salinity crisis is synchronous over the entire mediterranean basin dated at 5 96 0 02 million years ago isolation from the atlantic ocean was established between 5 59 and 5 33 million years ago causing a large fall in mediterranean water level followed by erosion 5 59 5 50 million years ago and deposition 5 50 5 33 million years ago of non marine sediments in a large lago mare lake sea basin cyclic evaporite deposition is almost entirely related to circum mediterranean climate changes driven by changes in the earth s precession and not to obliquity induced glacio eustatic sea level changes we argue in favour of a dominantly tectonic origin for the messinian salinity crisis although its exact timing may well have been controlled by the 400 kyr component of the earth s eccentricity cycle

the mediterranean messinian salinity crisis an apennine foredeep perspective abstract owing to its expanded stratigraphic sections the apennine thrust belt offers the opportunity to better understand the evaporitic and post evaporitic messinian events a physical stratigraphic framework of messinian deposits based on facies analysis and basin wide correlation of key surfaces and sedimentary cycles is presented it is shown that the messinian apennine foredeep had marginal basins with shallow water primary evaporites and deeper basins where resedimented evaporites accumulated under relatively deep water conditions like many other mediterranean examples primary shallow water evaporites of apenninic marginal basins show evidence for subaerial exposure and erosion however the development of such an erosional surface does not correspond to the deposition of primary evaporites in the deepest part of the basin s here the unconformity can be traced towards the base of resedimented evaporites or to a level within them implying that the deeper basins of the apennine foredeep never underwent desiccation during the messinian salinity crisis but rather received the eroded marginal evaporites this fact usually overlooked raises important questions about the deep desiccation model of the mediterranean

3d seismic analysis of circular evaporite dissolution structures eastern mediterranean buried circular collapse structures above a tabular evaporitic body are recorded by recently acquired 3d seismic data on the levant basin and continental margin offshore israel eastern mediterranean the structures formed during the pliocene as buried messinian late miocene evaporites underwent extensive dissolution in a submarine deep water setting three dimensional seismic analysis is used to describe the detailed morphology of the structures and the associated overburden allowing the reconstruction of their origin and development it is proposed that evaporite dissolution led to the collapse of the weakly lithified overburden and this deformed with a series of concentric extensional faults from the structural analysis of the overburden the estimated maximum duration of the dissolution event is 0 75 1 ma the mechanism proposed for the creation of the circular collapse structures is subjacent dissolution of the more soluble evaporites in the messinian evaporites as a result of focused vertical fluid flow at the base of the evaporitic series rapid release of overpressured fluids as for example during an earthquake is thought to have initiated the focused fluid flow which impinged on the evaporitic seal to the point where dissolution occurred creating the localized circular collapse structures in the overburden

intra to post messinian deep water gas piping in the levant basin se mediterranean abstract this study presents evidences for fluid flow manifested as pipe structures in the post evaporitic overburden characterised from a 3d seismic data from the levant basin offshore central israel interestingly these pipes are genetically and spatially contextualized east and west of the study area all rooted in the messinian evaporite substratum pipes in the western group accounts for 83 of the pipe population are crudely cylindrical oval to elliptical in planform with diameter and height ranging 350 2000 m and 320 420 m respectively internal configurations within this group varies from chaotic to concave upward reflections diagnostic of fluid induced collapse pipes in the eastern group are seepage pipes appearing conical in shape with height of 350 510 m and diameter of 320 420 m the eastern group pipes are characterized by lack of internal reflectivity and or disrupted stratal reflections the western group indicates an episode of fluid flow till the mid pliocene compared to late pliocene in the eastern group a conceptual model for the pipes in the western group is proposed to have occurred from subjacent dissolution of the messinian evaporite under deep water marine conditions during the pliocene by vertically focused fluid flow from intra messinian realm dissolving the top evaporites and inducing systematic collapse in the overburden the onset of which may have been triggered by seismicity conversely pipes in the eastern group are proposed to have developed from breaching the top evaporite by pressurized fluids that developed from lateral pressure transfer due to differential loading of the overburden and salt tectonics these pipe structures may pose a potential risk to deep water exploration and development the fluid expulsion phenomena documented in this study has wider implications for the hydrodynamics of many basins where thick evaporite layers are widely developed

the s receiver functions synthetics and data example summary recently the s receiver function method has been successfully developed to identify upper mantle interfaces s receiver functions have the advantage of being free of s wave multiple reflections and can be more suitable than p receiver functions for studying mantle lithosphere however because of specific ray geometry and interference of diverse phases the s receiver function method has some technical difficulties and limitations we use synthetic seismograms to demonstrate the feasibility and limitations of s receiver functions for studying mantle structures full wavefield seismograms were calculated using the reflectivity method and processed to generate synthetic s receiver functions for s sks and scs waves results show that s receiver functions can be obtained from waveforms of s sks and scs waves the synthetic s receiver functions for these incident waves show s to p converted phases at all discontinuities in the crust and upper mantle useful ranges of epicentral distances for calculation of s receiver functions are 55 85 for s 85 for sks and 50 75 for scs waves we apply both the s and p receiver function methods to data recorded at broadband station ykw3 in northwest canada the study shows that there is significant agreement among different receiver function methods and demonstrates the usefulness of s receiver functions for imaging the mantle lithosphere

epcrust a reference crustal model for the european plate summary we present a new crustal model for the european plate derived from collection and critical integration of information selected from the literature the model covers the whole european plate from north africa to the north pole 20 n 90 n and from the mid atlantic ridge to the urals 40 w 70 e the chosen parametrization represents the crust in three layers sediments upper crust and lower crust and describes the 3 d geometry of the interfaces and seismologically relevant parameters isotropic p and s wave velocity plus density with a resolution of 0 5 0 5 on a geographical latitude longitude grid we selected global and local models derived from geological assumptions active seismic experiments surface wave studies noise correlation receiver functions model epcrust presents significant advantages with respect to previous models it covers the whole european plate it is a complete and internally consistent model with all the parameters provided also for the sedimentary layer it is reproducible it is easy to update in the future by adding new contributions and it is available in a convenient digital format epcrust could be used to account for crustal structure in seismic wave propagation modelling at continental scale or to compute linearized crustal corrections in continental scale seismic tomography gravity studies dynamic topography and other applications that require a reliable crustal structure because of its resolution our model is not suited for local scale studies such as the computation of earthquake scenarios where more detailed knowledge of the structure is required we plan to update the model as new data will become available and possibly improve its resolution for selected areas in the future

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

erosional processes and paleo environmental changes in the western gulf of lions sw france during the messinian salinity crisis abstract current interpretation of the messinian salinity crisis msc involves partial desiccation of the mediterranean sea coupled with the deposition of thick evaporites in the deep basins new sets of seismic reflection profiles in the western part of the gulf of lions confirm the basinward extension of the messinian erosion and enable the mapping of distinctive seismic markers indicating the messinian erosional surface or messinian unconformity the basin margin detrital deposits and the deep evaporite sequence the geometrical relationship between these three elements and their relationship to the paleogeography of the margin during the msc provide new information about the evolution of the study area during the messinian the messinian erosional surface mes commonly correlated with the desiccation phase and the deposition of deep evaporites during the apogee of the event is generally interpreted as a subaerial feature in the gulf of lions it is a complex diachronic polygenic erosional surface observed at the base of the prograding plio quaternary sequence beneath the shelf and slope it extends downslope beneath the deep basin upper evaporites and the salt and possibly correlates conformably with the base of the so called deep lower evaporites the whole morphology of the mes reflects a buried drainage pattern supporting the interpretation of fluvial erosion driven by a substantial drop in sea level our results also suggest that large submarine gravity flows occurred prior to any significant accumulation of salt in the basin and prior to the upper evaporites consequently interbedded clastic deposits may partly account for the parallel reflectors of the lower evaporites since river erosion persisted throughout the msc the salt and upper evaporite units may also contain a large amount of detrital sediments the good quality of the new seismic data clearly reveals fan shaped messinian deposits in the downstream part of the main messinian valleys i e the nile var and spanish rivers the depositional scenarios generally involve a substantial sea level fall coupled with deltaic prodeltaic accumulations a chaotic seismic unit unit d filling messinian lows and extending beneath the salt within the study area is interpreted as a messinian clastic unit we propose a polyphase scenario of detrital fan deposition involving pre syn and post salt deposition in subaqueous subaerial environments in the gulf of lions a late miocene tectonic phase that affected the western shelf also played an important role in controlling a the pattern of the messinian fluvial network b the location of maximum erosion on the shelf and c the location of the detrital fan depocentre downslope

crustal structure beneath china from receiver function analysis 1 we collected and processed a large amount of high quality broadband teleseismic waveform data recorded by the 48 chinese national digital seismic network stations to estimate large scale lateral variations of crustal thickness and vp vs ratio hence poisson s ratio beneath china a statistical method was used to select mutually coherent receiver functions at each station which yielded over 200 traces for most of the stations with the conventional h the crustal thickness and vp vs ratio approach there is a large trade off between h and consequently multiple maxima are frequently observed in the h domain we introduced a weight function that measures the coherence between the p to s conversion and the reverberation phases at each h grid to reduce the trade off a 4th root stacking method was further applied to reduce uncorrelated noise relative to the linear stack these modifications turned out to be very effective in reducing the h trade off and yielded reliable estimates of crustal thickness and vp vs ratio the crust beneath eastern china is as thin as 31 33 km and the underlying moho is relatively flat and sharp in the western part of china the crust is considerably thicker and shows large variations the moho is observed at about 51 km depth along the tian shan fold system and about 84 km deep beneath the central part of the tibetan plateau the transition occurs at the so called n s belt between about 100 and 110 e which is featured by unusually high seismicity and large gravity anomalies the average vp vs ratio over the mainland china crust is about 1 730 0 249 significantly lower than the global average 1 78 0 27 of the continental crust this lower vp vs ratio may suggest a general absence of mafic lowermost crustal layer beneath china

aridity and humidity two aspects of the late miocene climate of north africa and the mediterranean abstract the physiography of north africa is not greatly changed from that of the messinian with the drawdown of the mediterranean in the late messinian the then existing river systems were incised into the landscape and emptied into lake cyrenaica which occupied the substantially drained eastern mediterranean basin the record of incision provides a record of the magnitude of the messinian river systems an analysis of these river systems demonstrates that messinian rainfall a consequence of the zeit wet phase was greatest in east and south central north africa in keeping with the derivation of the water mainly from the indian ocean in central north africa the eosahabi river flowed from messinian lake chad eroding the east tibesti valley and cutting a channel which is especially well preserved near the coast of the gulf of sirt the penetrated sediments of lake cyrenaica and the marginal basins of the messinian transgression are known as the upper evaporites and are generally fine clastics gypsarenites and gypsum anhydrite they were rapidly deposited underlying them is the halite of the lower evaporites this sequence of upper and lower evaporites is much like the lower halite of the tortonian south gharib formation and the overlying clastics and anhydrite of the messinian zeit formation in the gulf of suez red sea area this type of sequence is termed an evaporitic couplet and as has been demonstrated for the gulf of suez red sea is a consequence of a transition from a dry to a more humid climate in a restricted or semirestricted basin this transition occurred at about 7 5 ma in the gulf of suez red sea and at about 5 8 ma in the mediterranean the zeit wet phase manifest in the above events developed in association with the initiation and development of the asian monsoon and the drying of the mediterranean it can be understood in terms of the development of an evolving monsoon desert system the asian monsoon was initiated 8 7 ma in association with the uplift of tibet at this time the north african desert zone was displaced northwards to be over the mediterranean and central and eastern north africa became seasonally humid a concept is advanced in which the early stage of the development of the asian monsoon is seen as having two phases alternating at the precessional ca 21 ka cycle one phase transferred moisture from the indian ocean mainly to southern asia the other phase transferred moisture mainly to north africa with the drawdown of the mediterranean at about 5 8 ma the zeit wet phase intensified a further northward movement of the humid and desert zones occurred at the time of drawdown with the messinian and early pliocene transgressions the wet phase ameliorated but a substantial river system still crossed central north africa at about 4 6 ma north africa became drier probably in response to the developing dominance of the features of the monsoon that transferred moisture mainly to southern asia features of the monsoon that are well recognised today

the poisson ratio of the australian crust geological and geophysical implications the poisson ratio which depends on the vp vs ratio provides much tighter constraints on the crustal composition than either the compressional or the shear velocity alone the crustal poisson ratio can be determined from the joint analysis of the travel times of waves converted at the moho and of crustal multiples reflected at the top of the moho we have analyzed the records of the permanent stations installed on the australian continent complemented by the data of the skippy experiment the results reveal substantial variations in the poisson ratio in the different tectonic units for the proterozoic crust an increase of the poisson ratio with increasing crustal thickness is systematically observed while for the phanerozoic crust the poisson ratio tends to decrease for increasing crustal thicknesses these observations are in remarkable agreement with the results of the deep seismic soundings that were performed in the former soviet union the variations observed in the proterozoic provinces can perhaps be explained by underplating of mafic materials at the base of the crust fl 2000 elsevier science b v all rights reserved

active fragmentation of adria the north african promontory central mediterranean orogen global positioning system gps velocities indicate that adria no longer behaves as a rigid tectonic indenter into southern europe and is divided into northwestern and southeastern velocity domains differential motions are recognized in a velocity field determined from the peri tyrrhenian geodetic array ptga and international gps service igs sites in the circum tyrrhenian region of the central mediterranean and published gps velocities from the eastern adriatic coast in a fixed eurasian reference frame ptga and igs site velocities in sicily and southern italy are as much as 10 mm yr in a northward direction similar to gps velocities along the eastern coast of the adriatic sea in contrast velocities in northern italy are small or statistically insignificant and similar to velocities in sardinia and corsica outboard of western adria the tectonic boundary dividing adria is seismically active and passes around the southern and eastern margins of the tyrrhenian basin crosses central italy extends into the adriatic sea and follows the western margin of the dinaride tectonic belt north to the gulf of venice the eastern margin of adria is approximately located and follows the axis of the central dinaric alps southeast to the hellenic arc southeastern adria has a velocity related to northward motion of africa whereas northwestern adria has negligible differential motion in the eurasian frame and now is part of the alpine collage of southern europe

the moho depth map of the european plate summary the european plate has a 4 5 gy long and complex tectonic history this is reflected in the present day large scale crustal structures a new digital moho depth map is compiled from more than 250 data sets of individual seismic profiles 3 d models obtained by body and surface waves receiver function results and maps of seismic and or gravity data compilations we have compiled the first digital high resolution map of the moho depth for the whole european plate extending from the mid atlantic ridge in the west to the ural mountains in the east and from the mediterranean sea in the south to the barents sea and spitsbergen in the arctic in the north in general three large domains within the european plate crust are visible the oldest archean and proterozoic crust has a thickness of 40 60 km the continental variscan and alpine crust has a thickness of 20 40 km and the youngest oceanic atlantic crust has a thickness of 10 20 km

the buried afiq canyon eastern mediterranean israel a case study of a tertiary submarine canyon exposed in late messinian times abstract the afiq submarine canyon was one of a series of canyons initially incised in a drowned shelf edge and slope of the eastern mediterranean margins in early oligocene times p19 zone during most of the early miocene submarine erosion or non deposition prevailed this was followed by deposition of pelagic marls and debris flows in early middle miocene n8 times large scale sliding in late middle miocene times n14 resulted in the collapse of the slope the removal of most of the middle miocene sequence and the formation of a box shaped scar back cutting incision ultimately resulted in the incision of the shelf in late miocene times a sea level fall ranging between 50 and 800 m below the canyon s rim resulted in the deposition of the messinian lower evaporites mavqiim formation within the canyon a subsequent rise of a similar extent led to the deposition of the upper evaporites be eri gypsum which are found on the canyon s southern shoulder the final messinian sea level drop below the canyon s floor resulted in a subaerial environment in the canyon the erosion of the upper evaporites and the subsequent deposition of fluvial and brackish sediments afiq formation the latter correspond to the lago mare sediments known throughout the mediterranean the rapidly rising sea level during the pliocene along with the high rate of nilotic clastic sedimentation resulted in the final burial of the afiq canyon and a pronounced seaward progradation 20 30 km of the shelf edge

hydrocarbon seepage during the messinian salinity crisis in the tertiary piedmont basin nw italy abstract seep carbonate deposits of messinian age have been recently found in the tertiary piedmont basin nw italy these carbonates are preserved as blocks within a chaotic unit emplaced during the messinian salinity crisis msc they show negative 13 c values from 27 to 15 vpdb that indicate the involvement of hydrocarbon rich fluids in their genesis three types of carbonates are recognised i vuggy carbonates ii lucina carbonates and iii tubeworm carbonates vuggy carbonates are characterised by carbonate pseudomorphs after gypsum and probably formed during the first stage of the msc they are the product of a complex diagenesis influenced by both hypersalinity and seepage of hydrocarbon rich fluids these rocks lack chemosymbiotic assemblages reflecting their formation under extreme environmental conditions inhospitable for most metazoans in contrast lucina and tubeworm carbonates are characterised by chemosymbiotic macrofauna represented respectively by lucina bivalves and putative vestimentiferan tubeworms the latter have not commonly been documented in ancient seep carbonates and have never been reported from the messinian sediments of the piedmont basin both lucina and tubeworm carbonates are interpreted as the product of hydrocarbon seepage during the second msc stage these two types of carbonates formed under less severe conditions than the vuggy carbonates allowing the survival of seep dwelling metazoans during the second msc stage the seafloor was probably characterised by an irregular topography and a thin bottom layer of dense anoxic brines produced by the dissolution of gypsum it is suggested that vestimentiferan worms were able to thrive on morphologic highs with the posterior part of tubes just below the oxic anoxic interface but the anterior part projecting into oxic water the infaunal lucina bivalves were only able to live at seeps with an overlying oxic water column the studied carbonate deposits show features reflecting the uncommon interaction of hydrocarbon rich seep fluids and sulphate enriched waters the latter resulting from both evaporation and dissolution of gypsum and allow to reconstruct the evolution of a seepage system during the msc

on the formation and evolution of the pannonian basin constraints derived from the structure of the junction area between the carpathians and dinarides 1 the large number and distribution of rollback systems in mediterranean orogens infer the possibility of interacting extensional back arc deformation driven by different slabs the formation of the pannonian back arc basin is generally related to the rapid miocene rollback of a slab attached to the european continent a key area of the entire system that is neglected by kinematic studies is the connection between the south carpathians and dinarides in order to derive an evolutionary model we interpreted regional seismic lines traversing the entire serbian part of the pannonian basin the observed deformation is dominantly expressed by the formation of miocene extensional detachments and half grabens the extensional geometries and associated synkinematic sedimentation that migrated in time and space allow the definition of a continuous and essentially asymmetric early to late miocene extensional evolution this evolution was followed by the formation of few uplifted areas during the subsequent latest miocene quaternary inversion the present day extensional geometry changing the strike across the basin is an effect of the clockwise rotation of the south carpathians and apuseni mountains in respect to the dinarides our study infers that the carpathian rollback is not the only mechanism responsible for the formation of the pannonian basin an additional middle miocene rollback of a dinaridic slab is required to explain the observed structures furthermore the study provides constraints for the pre neogene orogenic evolution of this junction zone including the affinity of major crustal blocks obducted ophiolitic sequences and the sava suture zone

active tectonics of the adriatic region from gps and earthquake slip vectors 1 to investigate the kinematics of the adriatic region we integrate continuous and episodic gps measurements with mw 4 5 earthquake slip vectors selected from the regional centroid moment tensor catalogue coherent motion of gps sites in the po valley in apulia and in the hyblean plateau allows us to estimate geodetically constrained angular velocities for these regions the predictions of the gps inferred angular velocities are compared with the earthquake slip vectors showing that the seismically expressed deformation at the microplate boundaries is consistent with the observed geodetic motion the remarkable consistency between geodetic seismological and geological evidence of active tectonics suggests that active deformation in the central adriatic is controlled by the relative motion between the adria and apulia microplates the microplates angular rotation rates are then compared with the rotation rates calculated with a simple block model supporting the hypotheses 1 that apulia forms a single microplate with the ionian sea and possibly with the hyblean region and 2 that adria and apulia rotate in such a way as to accommodate the eurasia nubia relative motion we suggest that the present day microplate configuration follows a recent fragmentation of the adriatic promontory that during the neogene rigidly transferred the africa motion to the orogenic belts that now surround the adriatic region

alternate interpretation of the messinian salinity crisis controversy resolved a high resolution chronology of the mediterranean messinian salinity crisis is proposed two types of evaporite deposition may be distinguished those in marginal areas vs those in basinal ones their diachroneity is deduced from the stratigraphic relationships linking these evaporites to a major messinian erosional surface a two step model is proposed for the evolution of the salinity crisis through time during the first phase from 5 75 to 5 60 ma the deposition of marginal evaporites took place in response to a modest sea level fall in the second interval from 5 60 to 5 32 ma the mediterranean basin became isolated during this later period the deposition of basinal evaporites and the cutting of the mediterranean canyons took place

late tertiary subsidence history of the southern levant margin eastern mediterranean sea and its implications to the understanding of the messinian event the late tertiary subsidence history of the southern levant continental margin situated in the southeastern mediterranean sea was quantitatively analyzed paleodepth reconstruction across the margin off ashdod suggests the existence of a deep basin in pre messinian time which resembles the present one this implies that the deposition of the evaporites in the study area during the messinian desiccation of the mediterranean sea occurred in a deep basin the path of the tectonic subsidence of the basement since early tertiary is generally smooth as expected from the nature of the thermal subsidence the unconformity beneath the messinian indicates erosion of 50 200 m at the coastal plain in the pliocene the tectonic subsidence in the coastal plain and shelf area diverts from the expected thermal path and increases from 250 m to 450 m respectively in the quaternary the rate of tectonic subsidence nearly resumed the predicted thermal subsidence sedimentation and subsidence rates decrease but are still higher than those of the pre messinian we suggest that the evolution of the southern levant margin is most probably influenced by three main causes 1 the messinian event in late miocene 2 the deposition of large volumes of nile derived sediments since the pliocene and 3 the flexural response of the lithosphere to the load from the nile delta and or from the uplift of the judea mountains the western shoulder of the dead sea transform we interpret the latter to be the cause of the anomalous subsidence of the southern levant margin during the pliocene

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

lithosphere structure at the contact of the adriatic microplate and the pannonian segment based on the gravity modelling abstract two dimensional gravity modelling is applied to the contact of the dinarides and the pannonian basin as a contribution to solving structural and tectonic relations in the area characterised by very complex relations an interpretation procedure which improves the resolution of gravity modelling by the use of seismic refraction data has been developed on the alp07 profile which is set up in the framework of the alp 2002 seismic experiment and stretches in croatia from istra over the dinarides to the drava river seismic modelling was performed in order to determine the structure of the lithosphere a 2 d gravity modelling was also carried out on the profile to obtain calibrated rock densities using interfaces from the seismic model calibrated densities were applied to other profiles set up in the study area for the purpose of determining the structural relations the structural units determined on the alp07 profile pannonian crust transition zone and dinaridic crust can be easily followed on all other profiles the transition zone which separates the pannonian and the dinaridic crusts is very wide and characterised by lateral and vertical changes in velocities and densities it corresponds with the ophiolite zones in more recent tectonic maps the tisia block can be compared with the pannonian crust whereas the dinaridic crust would relate to the structural unites of the adriatic however the ne boundary of the transition zone is located much further north than the boundary of the tisia block in published tectonic maps due to a marked 2 d structure the obtained results enabled the development of a 3 d structural map of the mohorovicic discontinuity the main fault in the upper mantle which was defined on the basis of geometrical relations indicates a subduction of the adriatic microplate beneath the pannonian segment in the ne wing of the dinarides

crustal structure beneath broad band seismic stations in the mediterranean region summary we have analysed receiver functions to derive simple models for crustal structure below 12 broad band seismological stations from the midsea project and 5 permanent broad band stations in the mediterranean region including northern africa to determine an accurate moho depth we have reduced the trade off between crustal velocities and discontinuity depth using a new grid search method which is an extension of recently published methods to determine crustal thickness in this method the best fitting synthetic receiver function containing both the direct conversion and the reverberated phases is identified on a model grid of varying moho depth and varying poisson s ratio the values we found for moho depth range from around 20 km for intra oceanic islands and extended continental margins to near 45 km in regions where the eurasian and african continents have collided more detailed waveform modelling shows that all receiver functions can be well fit using a 2 or 3 layer model containing a sedimentary layer and or a mid crustal discontinuity on comparing our results with moho maps inferred from interpolated reflection and refraction data we find that for some regions the agreement between our receiver function analysis and existing moho maps is very good while for other regions our observations deviate from the interpolated map values and extend beyond the geographic bounds of these maps

lithology and characteristics of the messinian evaporite sequence of the deep levant basin eastern mediterranean abstract as the lithological composition of the messinian salt sequence of the levant basin is still controversial and unconstrained we reveal for the first time the lithology of the entire evaporite sequence from deep basin depth migrated seismic and borehole data the data presented here shows that the seismic transparent layers are composed of pure and uniform halite while the reflective layers are bundles of thin clay layers interbedded in the halite background the thin clay layers inside the deep basin evaporites have a cumulative thickness of 25 40 m high amplitude fan structures are observed on the deepest internal reflector which may suggest clay transportation among all the internal reflectors the upper units are more deformed while the deeper units are more coherent and flat two sets of folds faults are shown on the shallower intra units folds with nne ssw trending axes and thrust faults strike nw se on a regional scale the top salt reflector is generally horizontal while the other internal reflectors dip toward the nw the shallowest intra unit is the only one that has a wedge shape thickening to the nw while the other intra units generally have uniform thicknesses

mediterranean messinian salinity crisis constraints from a coeval marginal basin sorbas southeastern spain abstract the extent timing and effects of late miocene desiccation and evaporite deposition in the mediterranean sea remain controversial marginal basins containing messinian 5 3 7 1 ma sequences now exposed onland supplement information from the deep mediterranean but have evaporites of a variety of ages some of these messinian evaporites pre date and others post date deep desiccation none appears to be exactly coeval with those of the deep mediterranean in the betic cordillera of southern spain basins e g granada basin far from the present day mediterranean lost connection with the mediterranean due to uplift 1 ma before the salinity crisis and have marine evaporites of early not late messinian age in contrast basins such as the sorbas basin in southeastern spain adjacent to the present day mediterranean record events directly reflecting the course of the salinity crisis the sorbas basin retained marine connection with the western mediterranean up until evaporative drawdown in the mid messinian and was rapidly reflooded immediately afterwards the sorbas messinian sequence is up to 320 m thick it is complete and normal marine except for an incised basinwide erosion surface overlain by a 130 m thick gypsum deposit we propose that this surface marks the interval of deep desiccation of the adjacent mediterranean basin erosion occurred shortly after 5 9 ma and the irregular unconformity has relief of at least 240 m confirming mediterranean drawdown significantly below the atlantic level sorbas gypsum deposits overlie the unconformity and are intercalated with marls estimated at 5 5 ma containing normal marine messinian biotas these gypsum deposits therefore post date deep desiccation and formed in a silled basin immediately following marine reflooding they mark the end of the salinity crisis and are overlain by 70 m of normal marine sediments containing unreworked foraminifers of latest messinian age this succession demonstrates that the salinity crisis occurred faster and was completed sooner than previously believed it took place within 0 4 ma time scale of berggren et al 1995b is 0 2 ma on the time scale of baksi 1993 and was completed before the end of the messinian this corrects previous views that the salinity crisis continued until the early pliocene there is no evidence in the sorbas basin for brackish lago mare conditions and the normal marine biotas that directly precede and follow drawdown rebut earlier suggestions of prolonged salinity effects

deep water clastic evaporites deposition in the messinian adriatic foredeep northern apennines italy did the mediterranean ever dry out a new genetic facies model for deep water clastic evaporites is presented based on work carried out on the messinian gessoso solfifera formation of the northern apennines during the last 15 years this model is derived from the most recent siliciclastic turbidite models and describes the downcurrent transformations of a parent flow mainly composed of gypsum clasts the model allows clearer comprehension of processes controlling the production and deposition of clastic evaporites representing the most common evaporite facies of the northern apennines and the definition of the genetic and stratigraphic relationship with primary shallow water evaporites formed and preserved in marginal settings due to the severe recrystallization processes usually affecting these deposits petrographic and geochemical analyses are needed for a more accurate interpretation of the large spectrum of recognized gravity driven deposits ranging from debrisflow to low density turbidites almost all the laminar balatino gypsum previously considered a deep water primary deposit is here reinterpreted as the fine grained product of high to low density gravity flows facies associations permit the framing of the distribution of clastic evaporites into the complex tectonically controlled depositional settings of the apennine foredeep basin the messinian salinity crisis occurred during an intense phase of geodynamic reorganization of the mediterranean area that also produced the fragmentation of the former miocene apennine foredeep basin in this area primary shallow water evaporites equivalent to the mediterranean lower evaporites apparently only formed in semi closed thrust top basins like the vena del gesso basin the subsequent uplift and subaerial exposure of such basins ended the evaporite precipitation and promoted a widespread phase of collapse leading to the resedimentation of the evaporites into deeper basins vertical facies sequences of clastic evaporites can be interpreted in terms of the complex interplay between the messinian tectonic evolution of the apennine thrust belt and related exhumation erosional processes the facies model here proposed could be helpful also for better comprehension of other different depositional and geodynamic contexts the importance of clastic evaporites deposits has been overlooked in the study of other mediterranean areas based on the apennine basins experience it is suggested here that evaporites diffused into the deeper portions of the mediterranean basin may consist mainly of deep water resedimented deposits rather than shallow water to supratidal primary evaporites indicative of a complete basin desiccation

p and s velocity anomalies in the upper mantle beneath europe from tomographic inversion of isc data we present a new tomographic model for p and s velocity anomalies beneath europe 30 n 55 n 5 w 40 e extending in depth up to 700 km and constrained by inversion of data from the international seismological center isc catalogue the algorithm uses the traveltimes from events located in the study area recorded by all available worldwide stations as well as times from teleseismic events recorded by european stations the events from the isc catalogue have been relocated and combined into composite events all the traveltimes were corrected for crustal structure using the reference model eucrust 07 the resulting velocity anomalies show similar large scale patterns as observed in previous studies but have a higher resolution which allows detection of some features in more detail for example it is now possible to assess the depth extension of the small slow velocity body beneath the eifel region and eger graben the p and the s model show a good consistency in the uppermost 200 km below most of the european area and in some parts even in the deeper layers e g beneath the apennines and the hellenic arc the new model provides clear images of some principal features which were previously detected in a limited number of studies while the comparison between p and s velocity anomalies provides novel constraints to address on their nature e g the gap in the adriatic plate subducted below the central southern apennines in this paper we pay special attention to testing the reliability of the results the random noise effect is evaluated using a test with independent inversion of two data subsets with odd even events the spatial resolution is estimated using different checkerboard tests furthermore we present a synthetic model with realistic patterns which reproduces after performing forward and inverse modelling the same shape and amplitudes of the anomalies as in the case of the real data inversion in this case the parameters of the model can be used to assess the amplitudes of p and s anomalies that is critical for evaluation of other petrophysical parameters temperature density composition etc in the upper mantle 2009 the authors journal compilation 2009 ras