regional trends in active diapirism revealed by mountain range scale insar time series 1 we construct an orogen wide insar time series over the zagros mountains and eastern markan subduction zone in southern iran from 19 envisat tracks spanning 2003 2010 we observe active salt diapirism of the infra cambrian hormuz salt at 20 locations and identify several diapirs that are not moving all active diapirs reach the surface within the asmari limestone or older rock units while we do not observe any active diapirism occurring within younger exposures reflecting a complex vertical accumulation of the basal salt and reactivation of diapirs by erosion diapir reactivation of this sort may be a critical factor affecting the feasibility of sequestering nuclear waste and co2 in evaporite sequences over geologic time scales the distribution of active diapirism is indifferent to increases in mean elevation suggesting a relatively uniform thickness of the zagros fold belt above the basal salt with steps in topography driven by basement thickening we do not observe aseismic uplift of anticlines because rates are likely below the detection threshold of our time series this suggests that uplift is accommodated at small rates 2 3 mm yr over numerous structures instead of focused at the deformation front

salt tectonics driven by sediment progradation part ii radial spreading of sedimentary lobes prograding above salt experimental models indicate that sedimentary lobes deposited above mobile evaporites deform gravitationally by spreading outward radially radial spreading forms both concentric and radial families of thin skinned grabens that are then pierced diapirically by salt ridges the overburden blocks located between the ridges become subsiding depocenters later continued spreading after depletion of the salt layer forces salt ridges and diapirs to fall forming rapidly subsiding bathymetric lows that channel or trap younger sediments spreading causes large horizontal overburden movements whose distribution and orientation change when the locus of regional deposition shifts

rise closure and reactivation of the bicorb quesa evaporite diapir eastern prebetics spain the bicorb quesa diapir belongs to a complex system of evaporite diapirs located in the se iberian peninsula it was emplaced along the axis of a graben system flanked by two syn diapir growth basins filled by miocene sediments the miocene evolution of the diapir may be divided into three major phases an initial extensional phase during which the graben system formed and the diapir rose a second phase during which regional shortening closed the diapir and a third phase characterized by normal faulting during which diapirism was reactivated cutting the previously formed thrusts and folds this evolutionary trend demonstrates that diapirism was initiated and promoted by regional extension during the two extensional phases the diapir grew by reactive active and passive rise sedimentation during the reactive stage was characterized by strong basin subsidence sharp changes in sediment thicknesses and major coarse grained sediment input during the active stage the coeval basin fill sequence displays progressive angular unconformities gravitational deposits and subtle changes in thickness with the sediments unconformably overlying most of the earlier formed faults finally during the passive stage the sediments synchronous with diapir formation include abundant components from the extruding rocks and show gentler changes in thicknesses a progressive decrease in the input of coarse sediments and the deposition of mudstones and or lacustrine carbonates that clearly extend onto the faulted basin margins

evolution of salt diapir and karst morphology during the last glacial cycle effects of sea level oscillation diapir and regional uplift and erosion persian gulf iran abstract marine fluvial and cave sediments and karst phenomena were studied and dated by 14 c u series and osl methods to determine the evolution of the namakdan diapir and the world s longest salt cave 3n cave during the holocene and the last glacial sea level oscillations the uplift rate of the diapir and its surroundings and erosion are the main factors influencing the diapir morphology although the diapir uplift rate has been constant for the last 50 kyr 4 mm yr at a distance 600 m from the diapir edge the uplift rate decreases with the distance from the diapir center drag induced host rock deformation extends for 300 m from the outside edge of the diapir and host rocks in this zone have an uplift rate of 0 4 0 6 mm yr which is 2 3 times greater than the regional uplift rate based on known sea level oscillations radiometric dating and geological evidence the namakdan diapir was repeatedly flooded by sea water between 130 and 80 kyr bp submarine residuum composed mainly of gypsum and dolomite formed cap rock on the diapir after 80 kyr bp surficial drainage network and karst development started blind valleys and their corresponding cave systems evolved continuously for 20 30 kyr between 9 and 6 cal kyr bp the rate of sea level rise exceeded the namakdan diapir uplift rate by the factor of 3 as a consequence upward incision of cave streams paragenetic trend occurred and blind valleys near the seashore were filled with gravels cave passages now accessible on the namakdan and hormoz diapirs started to form 3 6 cal kyr bp when sea level stabilized and downward stream incision began older cave levels are still preserved but are filled with sediments and salt precipitates a comparison of the namakdan diapir evolution with data from the hormoz and larak diapirs shows that the evolution of diapir morphology is strongly affected by the differences in uplift rates and geological settings the general scheme of the evolution of the namakdan diapir is believed to be partly applicable to many other diapirs in coastal settings

classification and environmental models of cool freshwater tufas abstract tufa deposits are common in the quaternary record facies developments are dependent upon localised carbonate precipitation generally these take the form of phytoherm build ups together with associated detrital deposits derived from disagragation of the former phytoherm cements differ from speleothems and floe calcite accumulations in being biologically mediated or modified this paper recognises the following five types perched spring line cascade fluviatile paludal and lacustrine facies each type is composed of distinctive constructional and detrital sediment associations these unique sediment combinations are the product of an interplay between angle of slope water discharge rate standing water bodies phytal and microbial colonization and ambient temperature the proposed models will be of value in the interpretation of ancient and partially exposed tufas

cenozoic magmatism of the valencia trough western mediterranean relationship between structural evolution and volcanism abstract the cenozoic magmatism of the valencia trough is characterized by the existence of two volcanic cycles the first cycle early miocene middle miocene comprises calc alkaline rocks which have been recognized in the central to eastern offshore areas and in mallorca the second cycle middle miocene to recent is represented mainly by poorly differentiated alkaline rocks which are predominantly distributed along the iberian margin of the valencia trough in accordance with the inferred structural evolution of the valencia trough petrological and geochemical data as well as volcanological evidence we suggest that two different geodynamic environments existed during these magmatic cycles the early to middle miocene calc alkaline volcanism developed under compressive tectonic conditions and seems to be associated with the northwestern dipping subduction of the african plate in contrast the middle miocene to recent alkaline volcanism is associated with extensional tectonics and can be explained within the framework of a low volcanicity rift model three zones catalan valencian and columbretes each located at different parts of the rift structure can be distinguished in the middle miocene to recent volcanism this intraplate volcanism results from partial melting due to extension driven decompression with the largest degrees of melting in the centre of the valencia trough columbretes volcanic zone in the catalan volcanic zone a progressive increase in the extension rate from the first to the last volcanic episode has occurred favouring the interaction of two mantle sources

the influence of basement structure on the evolution of the bicorb quesa diapir eastern betics iberian peninsula contractive thin skinned deformation above a pre existing extensional basement fault on the basis of an analysis of structural surface data in addition to previously available and new magnetotelluric data it was possible to reconstruct the evolution of bicorb quesa diapir this was initiated as a reactive diapir in relation to a basement fault the reactive diapir was rejuvenated by a thin skinned compression during the paleogene and rose during an extensional early middle miocene phase later in the middle miocene the diapir was squeezed and then in the late miocene was extensionally reactivated the current reconstruction allows us to analyse a diapir affected by a thin skinned contractional deformation located on top of a pre existing basement fault our study highlights the role played by the geometric relationship between the propagation direction of the cover deformation and the basement fault

active salt tectonics in the needles district canyonlands utah as detected by interferometric synthetic aperture radar and point target analysis 1992 2002 1 the needles district in canyonlands national park utah is known for its well exposed array of extensional faults which are thought to be produced by gravity driven extension and downward flexure of a thin sandstone plate into the colorado river canyon in response to dissolution and flow of underlying evaporites halite and gypsum owing to a lack of precise geodetic data however it remains uncertain if and to what extent those extensional faults are currently deforming in this study we use synthetic aperture radar sar data to search for ongoing decadal ground displacements by applying both a stacking interferometric sar insar analysis and interferometric point target analysis ipta our results show that most of the needles district is indeed undergoing deformation now at a maximum rate of 2 3 mm year away from the satellite looking roughly westward with an incidence angle of about 20 also we identify a localized region along the riverbank that is uplifting at a rate of 2 3 mm year we estimate the measurement precision to be better than 0 8 mm year except along the riverbank where the errors are probably higher than this by analyzing residual signals and carrying out a signal recovery experiment using synthetic two dimensional correlated noise the deforming region is almost totally bounded by the colorado river canyon to the west and north a rapidly subsiding east west trending graben to the south and a relatively sharp to very diffuse deformation gradient to the east we observe deformation patterns that were previously undetected these include an area in the southwestern part of the deforming region that is deforming at higher rates than anywhere else in the needles but that has little surface extensional faulting rates of deformation are lower but still clearly significant further north in a region of spectacularly exposed fault blocks that have been previously studied in considerable detail

role of epikarst in near surface hydrological processes in a soil mantled subtropical dolomite karst slope implications of field rainfall simulation experiments epikarst exerts a strong control on run off generation in karst regions but it is still unclear in karst regions our study aimed to demonstrate the effect of epikarst on near surface hydrological processes in a subtropical cockpit karst region of southwest china using plot scale rainfall simulation experiments with different rainfall intensities low and high and antecedent moisture conditions dry and wet a trench excavated to the epikarst lower boundary allowed identification of flow pathways in the entire soil epikarst architecture system thus facilitating the water balance calculations using a conceptual model with the assumption of a two stage hydrological evolution more than 70 of the total rainfall water moved vertically through the shallow soil layer and then was redistributed by the epikarst as subsurface flow occurring on the soil epikarst interface depression filling on epikarst surface water held by epikarst and deep percolation epikarst water regulation capacity defined as the sum of depression filling on epikarst surface water held by epikarst epikarst seepage flow and deep percolation was 58 mm wet antecedent condition and 223 mm dry antecedent condition total run off from the soil epikarst system was dominated by saturated subsurface flow showing a threshold process controlled by epikarst storage capacity storing as much as 181 mm of rainfall water under dry antecedent condition our study proved that despite the epikarst being relatively poorly developed and covered by a soil mantle it still exerted a strong influence on near surface hydrological processes and thus should be adequately considered in future modelling of water recharge and depletion dynamics in this integrated soil epikarst system copyright 2015 john wiley sons ltd

insar mapping and modelling of an active iranian salt extrusion abstract interferometric synthetic aperture radar insar imaging is a powerful technique that is increasingly used to extract detailed 3d information on earth surface structures including exposed diapiric surfaces we have used insar to map for the first time the cumulative surface deformation in a 6 km 6 km region surrounding an active salt diapir syahoo and its associated surface salt flow or namakier exposed in the zagros mountains of southern iran images provided by the european space agency were acquired in 12 increments ranging in length between 35 and 1248 days over a 14 year interval between july 1992 and may 2006 the deformation of the salt surface is non steady with extrapolated rates of displacement varying between surficial uplifts of 1 4 mm day 1 511 mm a 1 and subsidence of 2 2 mm day 1 803 mm a 1 growth of a central topographic dome occurs following short wet intervals to create a salt fountain morphology which then slowly decays during the intervening long dry periods salt associated with dynamic bulging9 of the central dome during wet intervals may flow laterally via gravity spreading into the surrounding salt sheet resulting in deflation and subsidence of the dome which is counteracted by growth and inflation of the adjacent namakiers salt bulges9 that migrate down the namakier resulting in local inflationary and deflationary cycles of the surface may be regarded as episodic pulses of gravity spreading areas of inflation and deflation are also observed to commonly reverse during dry to wet periods as the overall salt system effectively self regulates as it continually strives for dynamic equilibrium as long as the source of salt remains undepleted gravity spreading of the dome ultimately results in more buoyancy driven salt flowing up the diapiric neck to replenish and feed the extrusion and maintain the gross fountain morphology

response of salt structures to ice sheet loading implications for ice marginal and subglacial processes abstract during the past decades the effect of glacioisostatic adjustment has received much attention however the response of salt structures to ice sheet loading and unloading is poorly understood our study aims to test conceptual models of the interaction between ice sheet loading and salt structures by finite element modelling the results are discussed with regard to their implications for ice marginal and subglacial processes our models consist of 2d plane strain cross sections which represent simplified geological cross sections from the central european basin system the model layers represent i sedimentary rocks of elastoplastic rheology ii a viscoelastic diapir and layer of salt and iii an elastoplastic basement on top of the model a temporarily variable pressure simulates the advance and retreat of an ice sheet the durations of the individual loading phases were defined to resemble the durations of the pleistocene ice advances in northern central europe the geometry and rheology of the model layers and the magnitude spatial distribution and timing of ice sheet loading were systematically varied to detect the controlling factors all simulations indicate that salt structures respond to ice sheet loading an ice advance towards the diapir causes salt flow from the source layer below the ice sheet towards the diapir resulting in an uplift of up to 4 m the diapir continues to rise as long as the load is applied to the source layer but not to the crest of the diapir when the diapir is transgressed by the ice sheet the diapir is pushed down up to 36 m as long as load is applied to the crest of the diapir during and after ice unloading large parts of the displacement are compensated by a reversal of the salt flow plastic deformation of the overburden is restricted to the area immediately above the salt diapir the displacements after unloading range between 3 1 and 2 7 m larger displacements are observed in models with deep rooted diapirs thicker ice sheets longer duration of the loading phase thicker salt source layers and lower viscosity of the salt the rise or fall of diapirs triggered or amplified by ice sheet loading are likely to affect glacigenic deformation erosion and deposition above the diapir and within the rim synclines ice load induced uplift in front of an ice sheet will provide favourable conditions for the formation of push moraines for example by creating a topographic obstacle and inclining potential detachments subglacial subsidence of salt structures will enhance erosion by providing a preferential drainage pathway and fracturing of the overburden of the salt structure and thereby contribute to the incision of tunnel valleys however the resulting displacements are probably too low to have a marked effect on the advance or retreat pattern of the ice sheets

geomorphic and stratigraphic evidence of quaternary diapiric activity enhanced by fluvial incision navarres salt wall and graben system se spain abstract the structural and stratigraphic geological features associated with salt structures have received extensive attention from geologists however there is limited work on the geomorphic and quaternary record of diapiric activity despite its practical implications e g salt and hydrocarbon extraction geostorage activities this work analyses the quaternary geomorphic and stratigraphic evidence of diapiric activity in the navarres salt wall se spain developed along the axis of a neogene graben this salt system is located in a region characterized by a peculiar network of orthogonal grabens that control the configuration and evolution of the drainage network the protruding salt walls are spatially associated with the erosionally unloaded and deeply entrenched graben sections situated close to the regional base level evidence of recent current activity in the navarres salt wall include 1 internally drained areas in a marginal withdrawal basin with long sustained aggradation 2 distorted drainage network defeated and deflected streams wind gaps knickpoints changes in fluvial style which changed from an initial axial longitudinal pattern to a longitudinal marginal distribution at the flanks of the salt wall 3 development of diapiric fault scarps at the edge of the salt wall 4 tilted fluvial terraces dipping away from the salt wall and with localized sediment thickening the available data indicate along strike variability in deformation style and long term vertical deformation rates these range from 0 09 mm yr to significantly higher values 0 2 0 4 mm yr in the section where the salt wall displays a more prominent relief and is affected by deep fluvial entrenchment the regional analysis and the characterization of the navarres salt wall suggest that quaternary diapirism in the region is enhanced by erosional unloading related to fluvial entrenchment which expands from the regional base level through the upstream propagation of an incision wave

u pb geochronologic constraints on the volcanic evolution of the mira avalon terrane southeastern cape breton island nova scotia new u pb ages for late precambrian volcanic and associated plutonic units in the mira avalon terrane of southeastern cape breton island indicate that volcanic suites were erupted over a span of a

plio quaternary extensional seismotectonics and drainage network development in the central sector of the iberian chain ne spain abstract westward propagation of postorogenic rifting in the central sector of the iberian chain generated the teruel and calatayud mio pliocene grabens and the jiloca daroca and munebrega plio quaternary half grabens partially superimposed on the western margins of the pre existing basins the progressive capture and transformation from endorheic aggradational to exorheic incisional drainage of the active grabens resulted in the development of a drainage network dominated by axial streams controlled by neotectonic activity and the distribution of basin fill lithofacies this paper reviews the geomorphic and stratigraphic evidence of plio quaternary extensional tectonics and provides new chronological data radiocarbon and osl dating on offset deposits and the associated paleoseismic record the daroca fault offsets mantled pediment deposits dated at 113 119 ka based on a radiocarbon age of the colluvial sequence 43 ka affected by the rubielos de la cerida fault a vertical slip rate of 0 05 0 07 mm yr has been estimated for this fault four paleoearthquakes subsequent to 72 ka have been inferred from the classic exposure of the concud fault indicating a recurrence interval of less than 18 ka a gravitational origin related to the dissolution of subjacent evaporites is attributed to two faults affecting an upper pleistocene terrace 15 ka in the alfambra valley close to the concud fault these structures have recently been interpreted as evidence of coseismic deformation on the concud fault although the faults have a low slip rate and a long seismic cycle their length

active salt deformation and rapid transient incision along the colorado river near moab utah in certain settings erosion is driven by and balanced with tectonic uplift but the evolution of many landscapes is dominated by other factors such as geologic substrate drainage history and transient incision the colorado plateau is an example where these controls are debated and where salt deformation is hypothesized to be locally active and driven by differential unloading although this is unconfirmed and unquantified in most places we use luminescence dated colorado river terraces upstream of moab utah to quantify rates of salt driven subsidence and uplift at the local scale active deformation in the study area is also supported by patterns of concavity along tributary drainages crossing salt structures subsidence in professor valley at a time averaged rate of 500 m myr meters million years is superimposed upon rapid bedrock incision rates that increase from 600 to 900 m myr upstream through the study area such high rates are unexpected given the absence of sources of regional tectonic uplift here instead the incision rate pattern across the greater area is consistent with a transient signal perhaps still from ancient drainage integration through grand canyon far downstream and then amplified by unloading at both the broad regional scale and at the local canyon scale

late cenozoic stress field and fracturing in the iberian chain and ebro basin spain detailed study of mesoscopic faults and joints affecting neogene and pleistocene deposits in the iberian chain and the ebro basin involving statistical study of fracture directions and palaeostress analysis from striated fault planes together with analysis of macrostructures suggest a complex late cenozoic stress field in which both primary and secondary stress systems are superposed 1 regional n s compression was caused by convergence between the iberian and african plates 2 multidirectional extension was caused by crustal doming in the iberian chain 3 stress trajectories were deflected near major faults 4 small scale swapping of the horizontal tension axes 2 and 3 was caused by development of fractures at right angles to either the primary or the deflected 3 axis

natural and human induced dissolution and subsidence processes in the salt outcrop of the cardona diapir ne spain the cardona diapir in ne spain with a salt outcrop about 0 9 km2 in area has a well developed endokarstic system that used to discharge into the cardener river underground mining for potassium salt carried out from 1930 to 1990 caused significant changes in the topography and hydrology of the diapir the accumulation of two halite slag heaps totalling around 10 million tons locally dammed the surface drainage creating closed depressions and preferential zones of water recharge the waters that infiltrated in one of these depressions largely derived from uncontrolled sewage disposal led to the generation of a 335 m long human induced cave excavated in one of the slag heaps moreover the inflow of freshwater from the surrounding sandstone aquifer caused by the excavation of a ventilation gallery resulted in the generation of a 280 m long cave in march 1998 the interception of a phreatic conduit by a halite mine gallery 50 m deep caused dramatic changes in the hydrology and geomorphology of the diapir including a a sudden decline in the piezometric level of the karstic aquifer b the inflow of freshwater and debris from the cardener river into the endokarstic system and the mine galleries a tunnel had to be constructed to divert the river flow from the salt outcrop c massive dissolution of salt creating new cavities and enlarging the pre existing ones including both mine galleries or cave passages the 4 300 m long salt meanders cave was largely generated by the inrush of water from the cardener river into the mine galleries and d the generation of a large number of sinkholes in the vicinity of the cardener river an inventory of 178 sinkholes has allowed us to estimate minimum probability values of 4 7 and 8 sinkholes km2 year for time intervals previous and subsequent to the 1998 mine flood event respectively

the neogene structure of the eastern iberian margin structural constraints on the crustal evolution of the valencia trough western mediterranean abstract the presence of a thinned crust beneath the valencia trough has been recognized for a long time however to date no attempt to link this thinning inferred from geophysical data with the superficial structures has been made a quantification of the neogene extensional processes in the crustal evolution of the valencia trough is presented as a consequence of the complexity of the betic balearic domain the analysis has been done for the catalan valencian domain northwestern areas of the trough crustal and superficial data in this area show that neogene extension was accommodated by a listric normal fault system detached in a deep upper crustal level 13 15 km in the marginal zone of the domain quantitative analysis of the neogene structure shows the incoherence between the upper crustal thinning inferred from the geometric analysis of the superficial structures factor 1 4 1 5 and from geophysical data 1 8 although the latter value agrees with that deduced from the analysis of neogene subsidence this incoherence suggests that the present thinned crust would be partially inherited from the mesozoic extension in this way mesozoic subsidence analysts and the recognized mesozoic structure show that the mesozoic extension was almost as important as the neogene one