composition and structure of the central aleutian island arc from arc parallel wide angle seismic data new results from wide angle seismic data collected parallel to the central aleutian island arc require an intermediate to mafic composition for the middle crust and a mafic to ultramafic composition for the lower crust and yield lateral velocity variations that correspond to arc segmentation and trends in major element geochemistry the 3 d ray tracing 2 5 d inversion of this sparse wide angle data set which incorporates independent phase interpretations and new constraints on shallow velocity structure produces a faster and smoother result than a previously published velocity model middle crustal velocities of 6 5 7 3 km s over depths of 10 20 km indicate an andesitic to basaltic composition high lower crustal velocities of 7 3 7 7 km s over depths of 20 35 km are interpreted as ultramafic mafic cumulates and or garnet granulites the total crustal thickness is 35 37 km this result indicates that the aleutian island arc has higher velocities and thus more mafic compositions than average continental crust implying that significant modifications would be required for this arc to be a suitable building block for continental crust lateral variations in average crustal velocity below 10 km roughly correspond to trends in major element geochemistry of primitive mg 0 6 lavas the highest lower crustal velocities and presumably most mafic material are detected in the center of an arc segment between unmak and unalaska islands implying that arc segmentation exerts control over crustal composition

sedimentary architecture of a prograding oolitic siliciclastic wedge response to changes in wave base oscillation kimmeridgian iberian basin abstract a detailed facies and sequential architectural analysis has been carried out along the wedge shaped shallow marine cross bedded oolitic siliciclastic ricla member kimmeridgian northern iberian basin the obtained results are based on fieldwork along the 4 1 km continuous outcrops with the use of high resolution photomosaics and drone made videos which have led to a precise and extensive facies reconstruction three main facies that are laterally related a to b to c in down dip direction have been differentiated which correspond to the topset foreset and bottomset parts of a sloping depositional surface sedimentation was controlled by sweeping drift and downwelling storm induced currents causing avalanching processes with the deep action of oscillatory currents the sedimentary architecture consists in 5 successive units composed by several sub units arranged according to different stacking patterns which reflect the sedimentary response to wave base oscillations superimposed to the regressive part of a third order transgressive regressive cycle the sedimentological features indicate that this unit which has been previously interpreted as a dune complex fit with an infralittoral prograding wedge model as it is observed in geographically close and stratigraphically similar units the ricla member is therefore regarded as an example of a well exposed grain supported unit with broad potential application to other prograding grain dominated lithosomes that do not conform to the traditional sand shoal model

human driven coastline changes in the adra river deltaic system southeast spain abstract the recent evolution of the adra river delta in southeastern spain has been reconstructed from historical maps aerial photographs and submarine multibeam bathymetric data we have distinguished three main evolutionary stages whose development took place as a direct response to the main anthropic and natural influences on the river system the first stage 4000 bc to 1872 ad represents the natural behavior of the deltaic system with negligible anthropic influence this long stage is characterized by coastline advance with the formation of a small asymmetric triangular delta in the natural river mouth and a typical prodeltaic deposit in contrast the second and third stages are characterized by anthropic interventions in the catchment and the river mouth which heavily modified the natural dynamics of the deltaic system the second stage 1872 ad to 1972 ad coincided with damming of the natural river channel very close to its mouth and the construction of two successive artificial channels to deviate the river flow the coastal dynamics changed during this second stage with erosion of the original delta and the formation of a new asymmetrical delta at the mouth of the artificial channels this younger eastern delta comprises two infralittoral wedges in the submarine realm which recorded changes of lateral redistribution processes and enhanced influence of energetic events and can only be explained if the sediment supply from the river source was reduced during this period the third stage 1972 ad to present day started with the damming of the trunk river in the central sector of the catchment thus drastically reducing sediment flow to the coastal realm and triggering general erosion and coastline retreat

clinoforms and clinoform systems review and dynamic classification scheme for shorelines subaqueous deltas shelf edges and continental margins abstract clinoforms are inclined and normally basinward dipping horizons developed over a range of spatial and temporal scales in both siliciclastic and carbonatic systems the study of clinoform successions underpins sequence stratigraphy and all efforts to reconstruct the relative partitioning of reservoir seal and source rocks along shoreline to basin floor profiles here we review clinoform research and propose a more systematic description and classification of clinoforms this is a crucial step to improve predictions of facies and lithology distribution within shoreline to continental shelf and abyssal plain successions together with the genesis drivers and dynamics of their constituent sedimentary units four basic clinoform types are here distinguished in delta shorelines lacustrine and marine environments on the basis of their overall spatial and temporal scale morphology outbuilding dynamic and geodynamic and depositional setting 1 2 delta scale clinoforms which in turns are sub divided into shoreline and delta scale subaqueous clinoforms 3 shelf edge clinoforms and 4 continental margin clinoforms delta scale clinoform sets are tens of metres high and typically represent 1 103 kyr with progradation rates ranging from 1 000 100 000 m kyr for shorelines and subaerial deltas to 100 20 000 m kyr for subaqueous deltas shelf edge clinoform sets are hundreds of metres high and are nucleated and accreted in 0 1 20 myr usual progradation rates of 1 100 m kyr by successive cross shelf transits of delta scale clinoforms continental margin clinoform sets are thousands of metres high hallmark key geodynamic crustal boundaries e g continent ocean transition and slowly prograde basinwards in ca 5 100 myr with typical rates of 0 1 10 m kyr as a consequence of the very different progradation rates and of the difficulty of large scale clinothems to backstep during transgressions shorelines are the most dynamic clinoforms with regards to position continental margins the least and shelf edges are intermediate shortly after a transgression therefore the four clinoform types may prograde synchronously along shoreline to abyssal plain transects forming compound clinoform systems during the subsequent regressive cycle however due to the dissimilarity in progradation rates different clinoform types will normally merge progressively with each other giving rise to hybrid clinoforms e g shelf edge deltas and fewer depositional breaks in slope are distinguished along a single shoreline to abyssal plain transect overall all clinoform systems are the result of the dynamic evolution of compound and hybrid clinoforms along a temporal and spatial continuum regulated by the cyclical backstepping of the smaller scale system within natural progradational retrogradational cycles of larger scale clinothem outbuilding all clinothem types may show either an accretionary active or draping passive style depending on the proximity to the sediment source draping clinothems are nearly always composed of condensed fine grained sediments while actively accreting clinothems can be composed of predominantly coarse grained i e reservoir forming or predominantly fine grained i e non reservoir lithotypes a novel hierarchical classification scheme for both recent and ancient clinoforms is here proposed consisting of 12 classes the four basic clinoform types delta scale shoreline delta scale subaqueous shelf edge and continental margin are sub divided into eight accretionary active and draping passive sub types 8 division each accretionary sub type is then sub divided into a sandstone prone and mudstone prone variant 12 division which can be at least tentatively predicted on the basis of the clinoform morphology even in the absence of direct stratigraphic logs

nucleation linkage and active propagation of a segmented quaternary normal dextral fault the loma del viento fault campo de dalias eastern betic cordillera se spain active faults from the campo de dalias se betic cordillera allow us to constrain the deformation styles involved in the development of segmented oblique slip faults this sector constitutes the widest outcrop of plio quaternary sediments in the northern boundary of the alboran sea it has emerged since the late pliocene and therefore provides recent deformation markers that are not disturbed by erosive processes the faults started to grow during the pleistocene reactivating previous hybrid joints with a normal dextral slip we present a detailed map of the largest fault in the area the loma del viento fault comprising six onshore segments based on field work and aerial photography the distributions of the contiguous joints have been mapped and the joints reactivated as faults are identified some of these fault segments are hard linked and fault slip enhances toward the linkage sectors between them with associated sedimentary depocenters an electrical tomography profile reveals the wedge geometry of a unit of pleistocene conglomerates and red silts that were coevally deposited during the fault movement long term slip rate in the central part of the fault is estimated at 0 07 0 03 mm y in addition a seismic crisis nucleated close to the loma del viento fault during november 2010 was recorded moment tensor analysis of the two mainshocks mw 3 5 and 4 2 provides a focal solution indicating a n120 e striking right lateral strike slip fault the corrugated morphology of the loma del viento fault may have influenced its seismic behavior some of the fault segments are oblique to the general motion of the fault these oblique segments would provide higher resistance against the general fault motion and could lock the fault leading to accumulate elastic energy

land sea correlation between late holocene coastal and infralittoral deposits in the se iberian peninsula western mediterranean the well exposed systems of prograding beach ridges on the carchuna calahonda granada and campo de dalias roquetas almeria coastal plains continue offshore as infralittoral prograding wedges ipw the holocene ipw is a narrow morpho sedimentary unit up to 2 5 km wide which develops seaward from the lower edge of the shoreface to 15 20 m depth extending to a well defined break of slope at water depths of 35 40 m these ipws have been recognized and studied using very high resolution seismic profiles topas and multibeam data em 3000d in detail they are complex morpho sedimentary units in which internal structures are closely linked to the pattern of progradation of the adjacent coastal plains when longshore currents produce significant littoral drift the ipws are composed of several minor units arranged in offlap which accrete parallel or oblique to the main shoreline therefore it is possible to correlate progradational units in the coastal plain h units sensu goy j l zazo c dabrio c j 2003 a beach ridge progradation complex reflecting periodical sea level and climate variability during the holocene gulf of almeria western mediterranean geomorphology 50 251 268 and subunits in the ipw but special care is required depending on the local arrangement of morpho sedimentary units besides it is not realistic to draw conclusions regarding the age of the subunits inside a given ipw without adequate dating as the number of subunits will greatly vary from place to place depending on local factors magnitude of sea level oscillations and sediment supply

integrated seismic studies of the baltic shield using data in the gulf of bothnia region in the autumn of 1989 a co operative experiment involving 12 research institutions in northwestern europe collected 2268 km of deep seismic reflection profiles in the gulf of bothnia and the baltic

characterization of non elastic ground behavior of a large underground power house cavern by back analysis abstract this paper presents results of a characterization procedure based on back analysis of a nonlinear deformation behavior of a discontinuous rock mass during excavation of a large underground power house cavern the objective is to introduce the concept of isolating effects of nonlinear joint deformation to be back analyzed from measured displacements and to demonstrate the effectiveness of this method for identifying strain distribution and deformational mechanism within a jointed rock mass

pattern and rate of post 20 ka vertical tectonic motion around the capo vaticano promontory w calabria italy based on offshore geomorphological indicators abstract the magnitude and rate of late pleistocene holocene vertical tectonic movements offshore of the capo vaticano promontory western calabria southern italy have been measured on the basis of the present day depth variations of the edges of submerged depositional terraces and associated abrasion platforms that formed below the storm wave base during the sea level stillstand of the last glacial maximum lgm these depositional features represented by submerged prograding wedges and an associated terrace shaped upper boundary have been identified in high resolution seismic reflection profiles acquired along the continental shelf and the upper slope of the promontory and are referred to in this study as lowstand infralittoral prograding wedges lipws our new data and methods provide evidence that lipws can be used as geomorphological indicators of vertical movements in offshore settings with well controlled uncertainty removal of the non tectonic component of vertical changes using an ice volume equivalent eustatic sea level compilation indicates 11 3 2 m of uplift and 25 3 2 m of subsidence from southwest to northeast along the promontory over a distance of 22 km during the post lgm the resulting uplift and subsidence rates including both regional and local components for the last 20 350 1 35 years are 0 54 0 2 mm y and 1 23 0 25 mm y respectively these results are consistent with longer term estimates based on uplifted 215 82 ka old coastal terraces and late holocene shorelines this integration of offshore and coastal markers indicates a pattern of vertical movements characterized by a marked asymmetry associated with a northeast down tilt of the capo vaticano promontory the calculated tilt rate increases by one order of magnitude during the post lgm in respect to the time interval from 215 to 82 bp displacement associated with the nw se striking normal fault that bound the capo vaticano promontory to the gioia tauro basin ended in the pleistocene and thus does not contribute to the tilt of the promontory at least during the last 215 ka

depositional model for a prograding oolitic wedge upper jurassic iberian basin abstract facies architecture and bedding patterns of the kimmeridgian pozuel formation iberian basin evidence that this 50 70 m thick oolitic grainstone unit conforms to the infralittoral prograding wedge ilpw model instead of the classic models used for interpreting oolitic grainstones sandbodies on carbonate ramps or platforms i e bank margin shoal complexes beaches and beach ridges ten lithofacies have been distinguished in the pozuel formation 5 10 dipping clinobedded oolitic grainstone foresets passing to tabular oolitic packstones grainstones which interfinger the muddy basinal bottomsets landwards the clinobeds pass into subhorizontal topsets composed of trough cross bedded to structureless oolitic grainstones oolitic skeletal grainstones with stromatoporoids and coral stromatoporoid microbial mounds siliciclastic lithofacies and oncolitic peloidal packstones occur at the innermost position these lithofacies stack in strike elongated 5 20 m thick 0 5 2 km dip oriented wide aggradational progradational packages with complex sigmoid oblique geometries lithofacies depositional geometries and stacking pattern permit to summarize the main characteristic of such upper jurassic oolitic infralittoral prograding wedge potentially to be applied in other oolitic sandbodies both in outcrops and subsurface 1 sediment production within the wave action zone 2 grainstone dominated textures 3 prograding basinward onto basinal muds 4 laterally strike extensive paralleling the shoreline 5 variable thickness commonly of few tens of meters 6 broadly sigmoidal to oblique internal architecture with topsets foresets and bottomsets 7 dip of foresets close to the angle of repose 8 topsets deposited in shallow water extending through the shoreface from the shoreline down to the wave base 9 mounds either microbial or skeletal may occur in the topsets the coated grains factory was along the high energy wave dominated outer platform topset beds from where the mud was winnowed and the grains transported both landward to the platform interior and seaward to the platform edge from were the grains cascaded down the slopes as grain flows and mass flows forming clinobeds this genetic model can be applied to other grain dominated lithosomes some of them forming hydrocarbon reservoirs e g the jurassic hanifa formation and some arab d e g qatif field in arabia the smackover formation in northern louisiana and south arkansas the aptian shuaiba formation e g bu hasa field and the cenomanian mishrif formation e g umm adalkh field of the arabian gulf

identification of future earthquake sources in the carpatho balkan orogenic belt using morphostructural criteria the carpatho balkan mountain belt the most seismic zone of the circum pannonian region is studied with a goal to identify sites where shallow earthquakes with m 6 5 may occur the study is based on the assumption that strong earthquakes associate with disjunctive nodes that are formed around the junctions of lineaments in the study region lineaments and disjunctive nodes were defined by a morphostructural zonation method the morphostructural map compiled at the scale of 1 1 000 000 shows a hierarchical system of homogeneous blocks the network of morphostructural lineaments and the loci of disjunctive nodes shallow earthquakes with m s 5 0 recorded in the region were found to be nucleated at the mapped nodes in the carpatho balkan mountain belt the nodes where earthquakes with m 6 5 may occur have been identified using morphostructural criteria of high seismicity previously derived from pattern recognition of potential seismic nodes in the pamirs tien shan region in total 64 of the 165 nodes mapped in the studied region have been defined to be prone to earthquakes of m 6 5 these 64 nodes include the seven where earthquakes of m s 6 0 already took place

submarine depositional terraces in the tyrrhenian sea as a proxy for paleo sea level reconstruction problems and perspective abstract in the last decade great effort was put in the study of relative sea level changes on mediterranean coastlines through the integration of geophysical modelling and proxy data of paleo shorelines in this paper we show potential and limitations of using additional marine geomorphic sedimentary markers for earlier and lower sea levels these markers are submarine depositional terraces sdts i e deposits formed by a set of small prograding sedimentary wedges having a terraced shape and found at variable shallow water depths mainly the first 150 m on continental and insular shelves in the tyrrhenian sea the shallowest terraces near shore have their edges at depths between 10 m and 30 m approximating the modern local storm wave base level their formation is thought to be associated with the modern sea level highstand and thus can be used as the modern analogue for deeper terraces formed in the past when the sea level was on the middle and outer shelf mid shelf terraces have their edges at variable depths between 40 m and 90 m and probably formed during the last sea level rise they show a patchy spatial distribution and a large variability in their internal structure so that they are not suitable for correlation on a regional scale shelf edge terraces have their edges at depths between 120 m and 170 m which is close or deeper than the last glacial maximum lgm sea level stand they show a remarkable lateral continuity and a prograding internal structure similar to those at shallower depth and thus represent a proxy for the sea level position at around 20 ka however the position of sdts edges is not a direct measure of paleo sea level positions because their depth depends on a complex interplay of several factors such as the base of the storm wave and its variation in response to coastal physiography as well as the occurrence of subsequent erosional or depositional processes depending on the geophysical and mapping methods used to determine their depth the associated error range can also differ based on the analysis of these complexities and a wide range of physiographic settings of the tyrrhenian sea we discuss these error ranges in order to assess potential and limitation of the sdt for analyses of vertical mobility of an area

holocene aeolian phases and human settlements along the atlantic coast of southern spain a combined geomorphological radiocarbon dating archaeological and historical approach permits a refining of the age of the coastal dune systems related to estuaries in the gulf of cadiz three dune systems are distinguished in this paper the oldest one d1 which accumulated under prevailing wsw winds during the first millennium bc overlays both the occupational horizons of late neolithic early copper age fourth millennium bc and the lithic workshop levels fourth to second millennia bc the middle dune system d2 containing both roman and medieval remains accumulated between the thirteenth or fourteenth centuries and the seventeenth century ad the youngest d3 system is associated with the time of building of watchtowers in the seventeenth century ad but extends to the present it is related to sw prevailing winds we explain the absence of aeolian deposits prior to 2700 cal bp as the result of trapping of a large part of the sediment supply in the estuaries which starved the neighbouring beaches and aeolian settings aeolian accumulation reached significant values when sedimentation in the coastal zone changed from being mainly aggradational in the estuaries 6500 2700 cal bp to mainly progradational in spit barriers and related dunes post 2700 cal bp the present analysis of aeolian systems suggests a non direct correlation at least in some cases between coastal progradation of spit barriers and aridity

the influence of shelf indenting canyons and infralittoral prograding wedges on coastal morphology the carchuna system in southern spain abstract submarine canyons and progradational sedimentary bodies are common features of continental margins worldwide few studies have analyzed the relationship between the coastal morphology and the morphology and sedimentary characteristics of the adjacent shelf in wave dominated coasts or the potential role played by shelf indenting canyons as inducers of sediment deposition in shallow waters this work presents a study that correlates the coastal morphology with the characteristics of the adjacent offshore shallow shelf in an area with a complex inner bathymetry the carchuna system spain the study area is characterized by large scale non rhythmic cuspate features in the coastline whereas the inner bathymetry exhibits a shallow water infralittoral prograding wedge ipw and a shelf indenting canyon that has tributaries located a short distance from the coastline using detailed bathymetric measurements observational data and wave propagation modeling the influence of the different bathymetric elements was quantified and a mechanism proposed for the generation of the carchuna ipw the wave propagation results show that the canyon is the main source of the alongshore modulation of nearshore waves and that it plays a major role in the generation of the large scale cuspate features in the shoreline additionally these results suggest that the long term coastal erosion associated with extreme storms yielded sufficient sediment which when subsequently transported eastward the dominant littoral drift direction formed the ipw once formed the ipw modified the wave propagation patterns and contributed to the development and reinforcement of the shoreline features

significance of bottom currents in deep sea morphodynamics an example from the alboran sea we present an interdisciplinary study of the geomorphology sedimentology and physical oceanography of the alboran sea south western mediterranean sea to evaluate the potential role of bottom currents in shaping the spanish and moroccan continental margins and adjacent basins bathymetric and seismic data have allowed the recognition of the contourite deposits including depositional plastered sheeted channel related mounded confined elongated and separated drifts erosive moats channels and furrows and mixed terraces and scarps features hydrographic data offer new insights into the distribution of the mediterranean water masses and reveal that bottom circulation of the western intermediate water wiw and the levantine intermediate water liw interact with the spanish slope and the western mediterranean deep water wmdw on the moroccan slope spanish base of slope and deep basins the integration of distinct datasets and approaches allows a proposal of a new sedimentary model for the alboran sea that details the significance of bottom current processes in shaping deep sea morphology this model considers the bottom circulation of water masses governs physiography that interface positions of water masses with contrasting densities sculpt terraces on a regional scale and that the morphologic obstacles play an essential role in the local control of processes and water mass distributions our findings demonstrate the pivotal role of bottom water circulation in seafloor shaping and sedimentary stacking patterns for continental margins establishing a new outlook for future studies of deep marine sedimentation

holocene highstand deposits in the gulf of cadiz sw iberian peninsula a high resolution record of hierarchical environmental changes a comparison of the internal structure of holocene highstand shallow marine deposits with emerged spit bar systems in the gulf of cadiz margin sw iberian peninsula is presented in order to increase the knowledge about the patterns of environmental fluctuations of sub milankovitch periodicity during the recent highstand period a high resolution seismic database of boomer profiles was interpreted focusing on shallow marine deposits of the gulf of cadiz shelf such as the guadalquivir river prodelta the guadiana river depositional system and the faro tavira infralittoral prograding wedge the results indicate that the internal architecture of recent highstand shelf deposits is complex as the recognition of three main types of seismic unit motifs suggests the existence of a hierarchical pattern of environmental fluctuations a major scale motifs the most significant feature observed in the seismic records is the pervasive occurrence of two major scale motifs lower and upper within the holocene highstand systems tract b intermediate scale motifs each major scale motif is composed of two intermediate scale motifs defining four intermediate scale motifs h1 to h4 c minor scale motifs the internal structure of major and intermediate scale motifs reveals a high degree of environmental variability during the recent highstand probably led by climatic cyclicities of submillenial scale the lower major scale motif is characterised by alternating progradational aggradational minor scale motifs whereas the upper major scale motif presents a more uniform internal structure dominated by progradational units the influence of two distinct trends or asymmetric cycles of sea level change seems to have been significant in the generation of the major scale architecture the transition between both major phases was probably related with a major sea level rise other factors such as changes in the magnitude and or direction of storm events and climatically induced changes of sediment supply are proposed to have controlled the generation of intermediate and minor scale architectures

tomographic study of crustal velocity structure in southern finland abstract an inverse tomographic problem of the construction of a 3 d velocity structure has been solved for depths of 10 20 30 and 40 km using the p wave arrivals registered by the seismic array in southern finland and on the dss lines sveka 1981 and baltic 1982 the interpreted results verify and enlarge dss data obtained earlier for a high velocity structure of the crust and explain some small lateral velocity variations the concordant tomographic and dss data specify a 3 d model for a complex geological structure in the region

density inhomogeneities of the upper mantle of the central balkans summary a 3 d density model was created for the central balkans area down to a depth of 670 km on the basis of seismic both artificial sources and earthquakes and gravity data this model is based on density columns constructed for the main geological units of the study region the densities for these columns were obtained using the density variation method this method makes it possible to extrapolate the density distribution from the well studied uppermost layers to the deeper levels of the earth the constructed 3 d density model was interpreted in relation to the available data on the heat flow and the seismicity of the region the subdivision of the region by the maritza fault into two parts the southern part including the rhodope massif and the northern part including the structures of alpine activation of srednogorie and the balkanides was confirmed the upraised position of the 400 km boundary within the upper mantle which was established from the density modelling is assumed to be a sign of development of recent geodynamical processes over the srednogorie block from the viewpoint of seismicity prediction a finding of mantle inhomogeneities orthogonal to the maritza suture is of great importance

the moho depth distribution in fennoscandia and the regional tectonic evolution from archean to permian times abstract from a variety of seismic refraction and reflection profiling results a new detailed moho depth map for the fennoscandian part of the baltic shield has been compiled a complementary crystalline crustal thickness map was compiled for denmark the skagerrak sea offshore western norway and adjacent areas where sedimentary strata reach maximum thicknesses of 10 km and even more these maps are discussed in relation to tectonic evolution and crustal ages of fennoscandia seismic velocities bouguer gravity and seismicity areas deviating from the proposed age thickness relationships are the kola peninsula archean and the oslo rift permian the average crustal thickness in the former area is around 44 km while the latter area is associated with a moho elevation of 3 5 km maximum crustal thicknesses in excess of 50 km have been found in southwestern and central finland and correlate with a crust of proterozoic age the caledonides of western norway do not exhibit as elsewhere a crustal root sub moho p n and s n seismic velocities are relatively small in that area and bouguer gravity values are strongly negative intracrustal p velocity variations do not seem to reflect geological age or specific tectonic features although the seismicity is moderate in fennoscandia most of the earthquake activity and in particular the largest earthquakes are confined to areas where the crustal thinning is most pronounced

millennial submillennial scale sea level fluctuations in western mediterranean during the second highstand of mis 5e abstract thispaperinvestigatesaseriesofsmall scale short lived uctuationsofsealevelregisteredinaprogradingbarrierspit thatgrew during the mis 5e this interglacial includes threehighstands zazoet al 2003 andwe focus on the second highstand of assumed duration 10 2 ka given that ueth ages do not providemoreaccuratedata geometryand3darchitectureofbeachfacies andthin sectionpetrographywereusedto investigate eight exposed of apping subunits separated by seven conspicuous erosion surfaces allinterpreted as the result of repeated small scale uctuations of sea level each subunit records a relatively rapid rise of sea level that generated a gravelly shoreface with algalbioherms and a sandy uppermost shoreface and foreshore where most sand accumulated a secondrange of still smaller scaled oscillations of sea level has been deduced in this phase of sea level uctu ation from lateral and vertical shifts of the foreshore plunge step uppermost shoreface facies eventually progradation with gently falling sea level took place and foreshore deposits underwentsuccessive vadose cementation and subaerial dissolution owing to relatively prolonged exposure laterrecovery of sea level re established the highstand with sea level at approximately the same elevation and there began deposition of a new subunit the minimum sea level variation fall and subsequent rise required to generate the observed features is 4 m the time span available for the whole succession ofevents and comparison with the holocene prograding beach ridge complex in the nearby roquetas almeria were used to calculate the periodicity of events a millennial suborbital time scale is suggestedfor uctuations separating subunits and a decadal scale for the minor oscillations inside each subunit 2010 elsevier ltd all rights reserved

depths of modern coastal sand clinoforms abstract clinoforms are classical geological features examples in the rock record or in seismic reflection data that originally formed in shallow water can potentially help to locate paleo sea level but their precise links with sea level need to be established using modern examples before such inferences can be made accurately some near shore areas of high wave energy and steep coasts host sand bodies with upwards convex surfaces these clinoforms have been suggested to have been created from sand exported from the upper shoreface during stormy conditions and deposited at depths where wave action diminishes below the threshold of motion field and roy 1984 hernandez molina et al 2000 we have compiled the shapes of these bodies in a variety of wave environments in order to test this idea the interpreted depths at which the sand surface steepens i e the clinoform rollover vary from 21 m off southern california to deeper than 50 m off se australia to assess the link with wave action rollover depths were compared with adjacent deep water wave properties over the period 1992 2001 in the era 40 reanalysis dataset rollover bed shear stresses were computed from properties representing average wave conditions and from properties associated with upper percentile conditions stresses were found to reach 0 1 0 5 pa during upper 5 percentile wave conditions exceeding the sediment threshold of motion estimated from reported grain size data sediment to below the rollover is therefore mobile during extreme wave conditions

environmental conditions and geomorphologic changes during the middle upper paleolithic in the southern iberian peninsula article i nfo this study utilizes geomorphology marine sediment data environmental reconstructions and the gorham s cave occupational record during the middle to upper paleolithic transition to illustrate the impacts of climate changes on human population dynamics in the western mediterranean geomorphologic evolution has been dated and appears to be driven primarily by coastal dune systems sea level changes and seismo tectonic evolution continental and marine records are well correlated and used to interpret the gorham s cave sequence specific focus is given to the three hiatus sections found in gorham s cave during heinrich periods 4 3 and 2 these time intervals are compared with a wide range of regional geomorphologic climatic paleoseismic faunal and archeological records our data compilations indicate that climatic and local geo morphologic changes explain the homo sapiens spp occupational hiatuses during heinrich periods 4 and 3 the last hiatus corresponds to the replacement of homo neanderthalensis by h sapiens records of dated cave openings slope breccias and stalactite falls suggest that marked geomorphologic changes seismic activ ity and ecological perturbations occurred during the period when homo replacement took place

origin of step like and lobate seafloor features along the continental shelf off rio de janeiro state santos basin brazil a combined analysis of seismic and morphological features identified in a set of high resolution seismic reflection and bathymetric data shows a systematic relationship between major modern seafloor morphological traces and the basinward migration of late pleistocene coastlines along the continental shelf of the santos basin rio de janeiro state se brazil observed fairly continuous and sinuous mid outer shelf escarpments are related to the sea level variations and shelf exposure during the last glacial cycle a bathymetric step at 110 m is an erosional remnant of offlapping detached forced regressive wedges that spread over 50 km in the shelf dip direction probably developed during periods of falling sea level between mis 3 and 2 a second major escarpment at 130 m was interpreted as the shoreline during the lgm at the time of most extensive subaerial exposure of the continental shelf however a distal escarpment at 150 m is expressed as a straight contour feature along the two main shelf edge embayments that characterize the shelf break this escarpment is coupled with a basal seaward inclined and highly eroded ramp and was interpreted as the erosional action of bottom currents during the last transgression due to the displacement of the southward flowing brazil current towards the present day outer shelf previously published articles have regarded the morphological features observed on the modern shelf as indicators of stillstands during the post lgm transgression we conclude that on the contrary most of these features are actually from earlier parts of the late pleistocene and were formed in a regressive scenario under oscillating and relative slow sea level fall

numerical methods in rock mechanics the purpose of this civilzone review paper is to present the techniques advances problems and likely future development directions in numerical modelling for rock mechanics and rock engineering

a beach ridge progradation complex reflecting periodical sea level and climate variability during the holocene gulf of almeria western mediterranean detailed mapping based on aerial photographs at various scales analysis of morpho sedimentary units and radiocarbon dating of the prograding beach ridge complex of campo de dalias almeria allow the differentiation of six prograding units these are called h1 7400 6000 cal bp h2 5400 4200 cal bp h3 4200 3000 cal bp h4 2700 1900 cal bp h5 1900 1100 cal bp and h6 500 cal bp present h units are deposited during periods of high relative sea level and increased sediment input to the coast they are bounded by large swales or erosional surfaces associated with lower sea levels and reduced input of sediment to the coast these correspond to short periods of increased aridity inside the general arid trend recorded in the western mediterranean since 5 4 ka changes in the flux of atlantic superficial waters into the mediterranean sea and relative strength of the w sw winds account for the recorded oscillations of relative sea level we deduce a decadal periodicity for the deposition of a beach ridge and the adjacent swale and suggest that it is related to fluctuations of the north atlantic oscillation nao index and to variations of solar activity the duration of h units shows a quasi millennial periodicity punctuated by short hundred years episodes of reduced progradation or erosion representing events of increased aridity likely to be related to bond s holocene cold events

architectural stacking patterns of the ebro delta controlled by holocene high frequency eustatic fluctuations delta lobe switching and subsidence processes abstract during the late pleistocene and holocene 125 ka b p to present a type 1 4th order depositional sequence comprising regressive lowstand transgressive and highstand system tracts formed worldwide the holocene 10 ka b p to present part of this contains the latest and present highstand systems tract hst within this and the underlying transgressive systems tract tst of the ebro delta in northeastern spain higher frequency 5th to 6th order sea level fluctuations are recognised these form retrogradational and progradational high frequency depositional sequence sets within the tst and hst respectively each high frequency sequence comprises 1 a basal highly reflective shell lag associated with an erosional transgressive surface 2 aggradational deposits which seawards consist of a wedge of marine clays with transparent seismic facies but inland are represented by thick peats 3 progradational deposits composed of sandy delta front facies displaying slope clinoforms these pass seawards into prodeltaic grey silts and landwards into red silts and pebbly sands of delta plain facies the progradational deposits downlap towards their bases the aggradational deposits formed in response to a period of rising sea level and a rapid increase in accommodation space progradation began when sediment supply to the delta exceeded accommodation space as a result of relative sea level fall the relative sea level curve for the delta has a stepped character caused by the punctuation of the 4th order sea level trend by higher frequency eustatic fluctuations as well as by high subsidence rates of about 1 75 mm per year the tst comprises retrogradational parasequences that onlap the underlying pleistocene gravels the maximum flooding surface separating the tst from the hst was formed about 6900 yrs b p on the basis of14c dating of peats the hst comprises progradational deltaic and aggradational units stacked as progradational high frequency parasequence sets the hst of the ebro delta is compared with other deltaic sequences around the world in particular with that of the mississippi delta a tentative chronology of the high frequency climatic and eustatic oscillations influencing deltaic sedimentation globally over the last 7000 years is presented

buried marine cut terraces and submerged marine built terraces the carchuna calahonda coastal area southeast iberian peninsula abstract the carchuna calahonda coastal area is located between the onshore betic cordillera and the alboran sea its onshore sector is formed by detrital sediments that cover a metamorphic basement mostly composed of marbles contiguous to an offshore shelf setting new onshore gravity data allow us to characterize the location of flat marine cut terraces carved into the metamorphic bedrock which are covered by detrital sediments in addition multibeam bathymetry data 3 5 khz and sparker reflection seismic profiles reveal offshore flat features linked to marine terraces that are related with the onshore buried marine cut terraces gravity data are newly used to detect marine cut terraces covered by sediments enhancing the integration of onshore and offshore data the marine terraces are distinguished based on the relative sea level trend regressive versus transgressive and on the dominant sedimentary regime erosional versus depositional these data help constrain the ages of the marine terraces younger than 150 ka using available late quaternary sea level curves although previous geodetic research suggests a rapid sinking of the carchuna calahonda coast the heights of the marine cut terraces and depositional terraces are mainly driven by sea level changes not tectonics

depositional history of estuarine infill during the last postglacial transgression gulf of cadiz southern spain abstract the late pleistocene and holocene evolution of the estuaries in the gulf of cadiz is interpreted for the first time using drill cores logs trenches and 38 new radiocarbon data and the results compared with the shelf the odiel tinto and guadalete rivers deposited conglomerates during a highstand that did not reach the present sea level dated at ca 25 30 ka isotopic stage is 3 corresponding to a relatively humid period in the area rivers incised these coarse grained deposits during the last main lowstand at ca 18 ka when sea level dropped to 120 m and the coastline lay 14 km seawards from the present the erosional surface is a sequence boundary and the flooding surface of the postglacial eustatic rise overlain by the valley fill deposits of the transgressive and highstand phases of the last fourth and fifth order depositional sequences recognised in the shelf the first marine influence in the estuaries during the transgression occurs at 25 30 m at ca 10 000 years bp according to fossil assemblages the transgressed basins changed from brackish to more open marine as the sea rose until ca 6500 years bp when it reached the maximum flooding and the sandy estuarine barriers ceased to retrograde toward the muddy central basins then the rate of eustatic rise decreased drastically and the estuarine filling followed a two fold pattern governed by the progressive change from vertical accretion to lateral centripetal progradation at ca 4000 years bp the fluvial input surpassed the already negligible rate of rise causing partial emergence of tidal flats and spit barriers in the largely filled estuarine basins prevalence of coastal progradation upon vertical accretion at ca 2400 years bp caused accelerated expansion of tidal flats and rapid growth of the sandy barriers further changes since the 16th century reflect widespread anthropic impacts

fractal analysis of seismic and geological data abstract continental lithosphere is a highly organised physical medium which can be investigated by seismic methods to obtain objective information the use of fractal representation offers new possibilities to determine quantitative parameters of the structural arrangement of the lithosphere and to compare tectonic structures composed of a similar set of participants i e structural complexes with a relatively homogeneous range of rocks fractals as a universal property of continental crust are shown to be an important tool for a comparative study of geological and seismic sections on a quantitative basis and also in reassessing many of the previous interpretations of seismic and geological structures

evidence for early proterozoic plate tectonics from seismic reflection profiles in the baltic shield plate tectonics provides the linking framework for all tectonic and magmatic activity seen today but it is not known when plate tectonics first developed on earth new deep seismic reflection and

linking early diagenesis and sedimentary facies to sequence stratigraphy on a prograding oolitic wedge the bathonian of western france aquitaine basin to improve the understanding of the distribution of reservoir properties along carbonate platform margins the connection between facies sequence stratigraphy and early diagenesis of discontinuities along the bathonian prograding oolitic wedge of the northeastern aquitaine platform was investigated eight facies are distributed along a 50 km outcropping transect in 1 toe of slope 2 infralittoral prograding oolitic wedge 3 platform margin shoal 4 open marine platform interior 5 foreshore and 6 terrestrial settings the transition from shallow platform to toe of slope facies is marked in the field by clinoforms hundred of meters long carbonate production was confined to the shallow platform but carbonates were exported basinward toward the breakpoint where they cascaded down a 20 25 slope ooid to intraclast grainstones to rudstones pass into alternating marl limestone deposits at an estimated paleodepth of 40 75 m three sea level falls of about 10 m caused the formation of discontinuities corresponding to sequence boundaries along these discontinuities erosional marine hardgrounds formed in a high hydrodynamic environment at a water depth of less than 10 m displaying isopachous fibrous cements and meniscus type cements the cements pass landward into meniscus and microstalactitic forms along the same discontinuities which are characteristic of subaerial exposure during the deposition of transgressive systems tracts carbonate accumulation remained located mostly on the shallow platform energy level increased and carbonates were exported during the deposition of highstand systems tracts forming the infralittoral prograding oolitic wedge during the deposition of lowstand systems tracts carbonate production fell to near zero and intraclast strata derived from the erosion of hardgrounds on the shallow platform prograded basinward early diagenetic cements are related exclusively to discontinuities that are not found within the prograding wedge because of the continuous high sedimentation rate under lower hydrodynamic conditions this absence of early cementation within the infralittoral prograding oolitic wedge was conducive to porosity conservation making such features good targets for carbonate reservoir exploration this study proposes a novel sequence stratigraphy model for oolitic platform wedges including facies and early diagenesis features

crust and upper mantle inhomogeneities beneath the central part of the balkan region abstract crustal and upper mantle velocity inhomogeneities are studied by the interpretation of the p wave travel times from local explosions and teleseismic earthquakes recorded in 30 stations on the territory of bulgaria and some neighbouring regions different methods of the solution of inverse 2 d and 3 d kinematic problems are used the established velocity inhomogeneities are discussed in connection with the major characteristics of some geophysical and seismotectonic fields it is noted that the velocity patterns of the crust reflect the configuration of alpine tectonic structures the subcrustal inhomogeneities are discordant to the main features of the near surface structures however these inhomogeneities are concordant to some seismic lineaments inexplicable from the viewpoint of the first order tectonic structures the observed relationship between the seismicity and deep velocity structures show that these lineaments are controlled by the uppermost mantle heterogeneities it is also noted that the high velocity zone in the deeper upper mantle indicates deep seated inhomogeneities beneath the rhodopean massif these inhomogeneities most probably represent palaeo subduction of a lithosphere slab penetrating deeper than 250 km into the asthenosphere

modeling the rollovers of sandy clinoforms from the gravity effect on wave agitated sand abstract clinoforms on coasts exposed to ocean waves form from sand exported from the shoreface during extreme wave conditions and deposited where wave action diminishes elsewhere it is shown that during upper 5 percentile wave conditions wave induced shear stresses exceed the sediment threshold of motion to below the clinoform rollovers experiments and theory suggest that where bed sediments are agitated by waves the effect of gravity should move particles down slope with a flux proportional to the slope combined with considerations of continuity this implies a diffusion of the sediment topography a property that would explain the smooth seabed morphology found at sandy rollovers where recorded with multibeam sonar for situations where this gravity effect dominates a simple analytical expression developed here shows how the rollover curvature should relate to wave properties and to the offshore component of sediment flux more sharply curved rollovers are expected where waves have short periods or where the sediment flux is large relative sediment fluxes were calculated using the model from rollover curvature and wave properties for sites from california southeast australia and atlantic and mediterranean iberia the relative magnitudes of the fluxes are roughly as would be expected from local physiography and coastal erosion rates for sandy clinoforms developed under mainly wave influences the model could be useful for exploring variations within clinoform datasets e g how varied convexity in an area of uniform wave properties reflects varied sediment flux and for interpreting how varied curvatures of rollovers within seismic stratigraphy reflect how wave climate and flux have varied in the past

evaporite evidence of a mid holocene c 4550 4400 cal yr bp aridity crisis in southwestern europe and palaeoenvironmental consequences sedimentological evidence for an abrupt dry spell in south eastern spain during the middle holocene from c 4906 to 4384 cal yr bp is presented this phase was determined primarily from halite beds deposited between muddy slimes in a lagoon system of puerto de mazarron murcia province with a peak phase from c 4550 to 4400 cal yr bp a multi core multi proxy study of 20 geotechnical drills was made in the lagoon basin to identify the main sedimentary episodes and depositional environments the results suggest that this halite bed more than 80 cm thick was conditioned by climate change and was accompanied by a generalized drying out of the basin halite precipitation was linked with palaeoecological changes including forest and mesophyte depletions and increasing cover and diversity of xerophytic plant species archaeological evidence indicates a demise of the population at this period probably due to resource exhaustion an overall picture of the biostratigraphy and palaeoclimates of the region is given in a broader geographical context

spatial analysis of mineral deposit distribution a review of methods and implications for structural controls on iron oxide copper gold mineralization in carajas brazil abstract mineral deposits are formed by interaction of various geological processes and conditioned by controls that favor their formation and preservation the understanding of mineralization controls is critical for mineral exploration because it allows focusing exploration on regions where these controls are concentrated the analysis of the spatial distribution of mineral deposits particularly on a regional scale can provide information relevant to the understanding of regional scale processes involved during their formation here we present a review of fry and fractal methods for spatial analysis of mineral deposit distribution and an application using the iron oxide copper gold iocg deposits of the carajas mineral province brazil results show that different iocg mineralization structural controls acted in scales of 40 km the iocg deposits cluster at scales of

the crust as a heterogeneous optical medium or crocodiles in the mist abstract based on petrophysical data geologic maps and a well log we present statistical descriptions of likely upper middle and lower crustal rocks to characterize the fine scale heterogeneity observed in crustal exposures and inferred from deep crustal seismic data the statistical models developed for granitic and metamorphic upper crust and for an extended metamorphic lower crust are used to construct whole crustal models of seismic velocity heterogenity we present finite difference synthetic cmp data from several models which compare favorably with field data the statistical models also permit classification of the seismic reflection experiment and the crustal heterogeneity according to scattering regime the optical or scattering properties of importance for classification are the velocity fluctuation intensity the horizontal and vertical correlation lengths of the medium the correlation function of the medium and the velocity population function for the crustal properties we measured the bandwidth of a typical deep crustal experiment overlaps from the weak to the strong scattering regime with implications for crustal seismic data processing and imaging notably deep crustal signals are likely to have experienced multiple scattering making common seismic imaging techniques of questionable value moreover the details of the unmigrated cmp stacked section bears little resemblance to the underlying medium

a tomographic crustal velocity model of the central fennoscandian shield summary in this paper local seismic tomographic method is used to find the terrane distribution within the central parts of the accretionary svecofennian orogen this study presents a crustal pwave velocity model and for the first time the s wave velocity and vp vs ratio model of svekalapko area that is 700 800 km 2 in southern and central finland the 3 d model is presented as p and s wave velocity as well as vp vs ratio depth slices and vertical sections the data set comprised of several subsets of crustal pg and sg wave traveltime data from local events recorded by the svekalapko seismic tomography array in 1998 1999 from older controlled source shots recorded at portable stations as well as at permanent stations and from non controlled chemical explosions recorded at permanent seismic stations from 300 local explosions a total of 10 404 pg wave and 9361 sg wave arrival times were inverted to create independent 3 d vp and vs tomographic models from which the vp vs ratio was calculated according to sensitivity tests the optimal horizontal resolution of recognizable velocity structures in the central study area is at least 60 km down to depths of 40 km in the final model the seismic velocities vary smoothly the lateral variations are larger for vp 5 9 6 6 km s 1 than for vs 3 5 3 8 km s 1 in the upper 20 km of the crust at depths of 20 40 km vp varies from 6 5 to 7 2 km s 1 and vs from 3 7 to 4 1 km s 1 the vp vs ratio varies spatially more distinct than p and s wave velocities usually from 1 70 to 1 74 in the upper crust and from 1 72 to 1 78 in the lower crust schist belts and their continuations at depth are associated with lower velocities and lower vp vs ratios vp 6 2 6 8 km s 1 vs 3 6 3 9 km s 1 vp vs 1 68 1 73 than the granitoid areas vp 6 3 7 4 km s 1 vs 3 6 4 2 km s 1 vp vs 1 72 1 78 the svecofennian orogen was accreted from crustal blocks ranging in size from 100 100 km 2 to 200 200 km 2 in cross sectional area the intervening sedimentary belts have ca 0 2 km s 1 lower p and s wave velocities and ca 0 04 lower vp vs ratios tomographic model supports the idea that the thick svecofennian crust was accreted from several crustal terranes some hidden and that the crust was later modified by intra and underplating

seismic stratigraphic analysis of the middle jurassic krossfjord and fensfjord formations troll oil and gas field northern north sea abstract the syn rift middle jurassic krossfjord and fensfjord formations troll field northern north sea contain a complex distribution of wave and tide dominated deltaic shoreline and shelf depositional environments of varying reservoir potential uncertainty exists in depositional models used to explain the spatial and temporal distribution of these depositional environments and the absence of coeval coastal plain deposits to date the proposed influence of growing rift related structures on stratigraphic architectures and sedimentation patterns in the units has been poorly defined in this study 3d seismic data are integrated with core biostratigraphic and wireline log data to produce a consistent geological interpretation for the formations seismic analysis has identified nine parasequences containing nne ssw striking delta scale clinoforms that prograded westwards over much of the field quantitative analysis highlights an increase in height and dip of clinoforms from proximal to distal locations coincident with an increase in grain size clinoform geometry is sigmoidal with well developed topsets that based on core data lack subaerial deposits these geometrical and sedimentological characteristics suggest that a subaqueous delta depositional system deposited the krossfjord and fensfjord formations in the troll field in the northeast of the field clinoforms exhibit highly variable strike and oblique cross sectional geometries which suggest that sediment was supplied from here and then redistributed through southward directed wave and longshore current activity rift related faulting is recognised to have occurred in the western part of the troll field only during deposition of the youngest fensfjord formation parasequence thus challenging the notion that these units are syn rift seismically imaged clinoforms in the under explored area south of the troll field prograded southward and are interpreted to represent coeval formation of a southward prograding spit that developed landward of the subaqueous delta platform present in the troll field the interpreted long lived subaqueous delta in the troll field constitutes a novel type of shallow marine reservoir

an unusual holocene fan shaped subaqueous prograding body at the back of the cies islands ridge ria de vigo nw spain geomorphology facies and stratigraphic architecture abstract the internal structure of a new subaqueous sedimentary body with a 3d morphology of a fan was studied using an interdisciplinary approach based on geophysical geomorphological sedimentological and radiocarbon data the genesis of the sedimentary body is controlled by two main factors 1 the presence of a basement ridge that constitutes the cies archipelago acting as a barrier that protects the ria from high energy marine events and 2 the w sw swell direction under stormy conditions which sweeps the sediment from the platform and introduces it into the ria through the narrow entrance between faro and san martino islands the sedimentary body that has grown inside the ria under low energy conditions progrades in a landward direction from the shelf to the ria sedimentological analysis indicates that the facies associations are coarse grained bioclastics in the proximal areas of this body changing laterally to mixed fine grained sediment in its distal parts the combination of geophysical and radiocarbon data leads us to establish the beginning of the progradation of the sedimentary body subsequent to the younger dryas cold event associated with the holocene sea level rise the seismic analysis of the high resolution seismic records allows us to recognize five main clinoform sets inside the subaqueous prograding sedimentary body which can be attributed to sea level changes during the holocene

the late cretaceous to holocene sequence stratigraphy of a sheared passive upper continental margin northern kwazulu natal south africa abstract high resolution single channel seismic data reveal seven seismic units a g from the narrow and steep upper portions of the sheared passive continental margin of northern kwazulu natal several characteristic internal geometries are evident onlapping sheet like unit c aggradational progradational unit a and facies d3 and progradational unit b facies d1 2 and facies g1 on the basis of internal geometry and bounding unconformities lowstand units b facies d3 and lowermost unit g possible transgressive unit c highstand upper unit g and falling stage facies d1 and d2 systems tracts are delineated units e and f are not reconcilable due to acoustic opacity overall five incompletely preserved sequences are observed sequence one comprises unit a of suspected middle maastrichtian age separated from the overlying sequence by a subaerial unconformity surface sb1 units b and c form sequence two and span the late cretaceous late maastrichtian to mid late palaeocene two major hiatuses ensued angus and jimmy until mid pliocene times when unit d was deposited during shelf margin advance linked to hinterland uplift these falling stage systems tract deposits are separated from latest pliocene early pleistocene lowstand shelf edge deltaic deposits by a subaerial unconformity marking the deposition of sequence four facies d3 the age of unit e is uncertain unit f represents a series of shorelines formed during oxygen isotope stage ois 5a to 2 on the regressive and transgressive limbs preceding and following the last glacial maximum lgm the final partial sequence preserved is comprised of unit g formed during the ois 2 transgression to present mean sea level and subsequent development of the contemporary highstand wedge in terms of stratigraphic architecture this study shows an evolution from a ramp style margin with a poorly defined shelf break to that of a shelf break profile with a narrow and steep shelf in this respect the narrowness of this shelf cannot be accounted for by the inheritance of shearing effects rather the stratigraphic architecture reflects a period of slow and protracted subsidence with strong sediment dispersal later punctuated by hinterland uplift this formed the late pliocene shelf margin clinoforms of unit d and established the shelf break position at the offlap break of this wedge the resulting narrow shelf may play a significant role in the preservation of later sequences particularly in light of the continued uplift of the margin causing off shelf sediment bypass where tst and hst sequences may not be preserved this is reflected in the isolated preservation of shoreline and shallow marine deposits of the pleistocene units e and f

upper mantle heterogeneities beneath eastern europe abstract p wave travel time residuals for seismograph stations in eastern europe as reported by isc for the years 1964 1977 were used for constructing a seismic image of upper mantle heterogeneities in the network region for the depth range 0 100 km dominant tectonic features like the pannonian basin and the aegean sea and western turkey correlate well with pronounced velocity lows which a ppear to extenddown to a 300 km depth the velocity anomaly patterns in the depth intervals 300 500 km and 500 600 km are broadly similar but quite different from those of shallower depths the observed seismic heterogeneities are briefly discussed in terms of large scale tectonic and geophysical heat flow characteristics of eastern europe

late pleistocene holocene sediments on the spanish continental shelves model for very high resolution sequence stratigraphy abstract sequence stratigraphy analysis of high resolution seismic profiles geopulse uniboom and 3 5 khz of late pleistocene holocene sediments has been carried out on five sectors of the spanish continental margin four types of depositional settings are distinguished in these sectors 1 low subsident ramps alboran margin cadiz gulf 2 high subsident 2m kyr ramps alicante valencia 3 ria type morphology on the atlantic passive margin ria de muros and 4 fault scarp morphology systems with subsidence balearic margin a type 1 sequence is interpreted in all these sectors being composed of lowstand systems tract transgressive systems tract and highstand systems tract this conforms to the basic concepts of sequence stratigraphy and each systems tract correlates with a particular part of the last eustatic hemicycle characteristic shelf features such as terraces terraces with beach deposits and progradational sediment wedges evidence a complex stacking of lesser sub sequences in all the systems tracts which must be related to very short period sea level stillstands and fall we propose a very high resolution sequence stratigraphy model in which the last sea level hemicycle is punctuated by p cycles 4500 years which give rise to the neo glacial events h cycles 2200 950 years and c cycles 500 50 years these cycles interact with each other thus establishing the placing of the high and low sea levels this attention to detail 1 explains sedimentary evolution on both the shelf and upper slope during late pleistocene holocene time 2 illustrates some departures from the classical sequence stratigraphy model and 3 also demonstrates that the late pleistocene holocene eustatic curve is not one simple transgression but is modulated by three differing period cycle groups below the milankovitch band our model is delimited by fluctuating sea level during pleistocene holocene times such features should be identifiable on any continental margin however localized features occur due to subsidence and continental shelf morphology which determ ine the location and depth of sedimentary bodies generated in each eustatic cycle

eurid a regionalized 3 d seismological model of europe abstract this paper presents a 3 d regionalized model of the european crust and mantle velocity structure down to depths of approximately 300 km the model is entirely based upon the existing geological and geophysical literature and it incorporates topographic and bathymetric features the resulting model which we call eurid european i data set consists of approximately 6400 1 d vertical structures having an average separation of about 100 km eurid is compared quantitatively with eur s91 a recent s wave velocity tomographic model obtained from body and surface wave waveform inversion zielhuis a nolet g 1994 shear wave velocity variations in the upper mantle beneath central europe geophys j int 117 695 715 it is found that the s wave velocities in eurid and in eur s91 zielhuis and nolet 1994 do not differ by more than about 4 over most of the area to validate eurid surface wave dispersion analysis is performed along some selected paths the fundamental mode group velocity curves obtained using 1 d average models derived from eurid are found in good agreement with those determined from observations broadband waveform synthetics are also calculated along the same paths and compared with the observed time series overall we believe that eurid is representative of our current knowledge of the crust upper mantle structure beneath europe and it can be used to model realistically ground motion for periods above 10 s within structurally homogeneous regions the first digital version of this structure database is available for public use

variations in the structure of the anticyclonic gyres found in the alboran sea historical satellite aircraft and in situ data have shown that two anticyclonic gyres the western and eastern alboran gyres are major ocean features of the alboran sea an examination of several years of satellite imagery indicates that large variations in the surface expression of these two gyres occur and that on occasion one or the other gyre disappears the disappearance of both gyres at the same time was not seen the initial disappearance of either gyre occurs on a time scale of a week to 2 weeks whereas the return may take from 3 weeks to 2 months various forcing mechanisms i e winds mass flux inflow through the straits of gibraltar and sicily and or density have been used in numerical ocean circulation models to study the dynamics of the western mediterranean sea various model results show relationships similar to those shown by the satellite imagery however no single forcing mechanism has been positively identified as the source of the disappearances and the events may be a result of a combination of forcing mechanisms

the fractal nature of structural controls on ore formation the case of the iron oxide copper gold deposits in the carajas mineral province brazilian amazon the formation of ore minerals in hydrothermal deposits is the result of a complex interplay between physical and chemical processes that are conditioned by the geologic environment in which they occur in the last decades research has increasingly indicated that many of these processes display different forms of scale invariance i e they show fractal geometry this suggests that behind the apparent disorder and irregularity of the geometry of mineral deposits at different scales an underlying regular pattern is present if properly understood this regular geometrical pattern could be useful in a variety of theoretical and applied fields a great portion of this scale invariance is given by the structural framework during mineralization because structures are a dominant factor controlling fluid flow here we assess the geometry of iron oxide copper gold iocg mineralization in the world renowned carajas mineral province focusing on one of the largest and most economically important orebodies the sossego deposit the geometry of mineralization is evaluated at the microscale ore minerals in thin sections local scale orebodies in mine maps and regional scale deposit distribution on regional maps we show that the spatial distribution and shape of ore minerals at the microscale is largely nonrandom presents fractal geometry and displays defined trends in spatial distribution and anisotropy additionally the geometric trends observed at the microscale mimic those of the local scale geometry of orebodies as well as the regional scale distribution of mineralization the main property controlling the observed scale invariance is permeability which is intrinsically associated with structures at multiple scales these results contribute to further understanding the fractal nature of processes controlling mineral deposit formation and revealing new multiscale approaches to investigate structural controls on ore deposition

sandy berm and beach ridge formation in relation to extreme sea levels a danish example in a micro tidal environment abstract the formation of berms and their transformation into beach ridges in a micro tidal environment is coupled to wave run up and overtopping during extreme sea levels a straight forward comparison between extreme sea levels due to storm surges and active berm levels is impossible in the semi enclosed bays along the baltic sea quite often the maximum water levels do not coincide with the maximum intensity of the wave driven processes because of seiches in the baltic in this paper we look into the joined distribution of extreme water levels and high energetic wave conditions at feddet a sandy prograding spit on the south eastern baltic shores of zealand denmark the modern sandy beach at this location consists of a beachface with a shallow incipient berm a mature berm and a dune covered beach ridge it borders a beach ridge plain to the west where more than 20 n s oriented beach ridges and swales are present measured water level data from 1991 to 2012 and topographical observations carried out during fair weather period and during a storm event provided the basis for a conceptual model exhibiting berm formation and transformation into the local beach ridge system the character of extreme sea level events is identified using thirty three well described extreme events throughout a period of 15 years analysis of the meteorological conditions during these events revealed that berm formation only occurred during 20 of all extreme events when onshore winds high energy wave action and elevated water coincided these berm forming events had a mean return period of once every three years the average age between successive beach ridges on the beach ridge plain was about 180 years which means that the transformation of a berm into a single beach ridge is the result of a large number of storm episodes with high energy waves and extreme water levels