the tectonic evolution of the zoumi sandstone western moroccan rif the zoumi sandstone is an oligo miocene syn tectonic flysch sequence deposited on the back of the mesorif thrust sheet whose sediment source was from the foreland to the south variations within the zoumi sandstone from thick to thin bedded turbidite lobes are explained as the result of deposition in small confined basins or larger more extensive basins respectively formation of small basins is related to contractional deformation in the underlying mesorif thrust sheet propagation of the zoumi thrust through the developed basin with areas of relative uplift and subsidence produced complex hanging wall cutoff geometry a complicated footwall geometry exists because deformation in the more external mesorif thrust sheet preceded the final displacement of the more internal intrarif thrust sheet the latter incorporated the zoumi sandstone into its leading edge and thrust it over the mesorif during the miocene this deformation sequence of two or more simultaneously active thrust sheets is described as synchronous thrusting

definitive evidence of hesperian basalt in acidalia and chryse planitiae 1 the surface materials of acidalia and chryse planitiae mars have been variably interpreted morphologically as basalt and compositionally as andesite or altered basalt a thorough survey using the compact reconnaissance imaging spectrometer for mars crism near infrared spectrometer reveals olivine and high calcium pyroxene signatures in the shallow subsurface exposed by impact craters these signatures indicate that the near surface of these regions are primarily basaltic in nature and are similar to other regions of hesperian volcanism across mars e g syrtis major previous spectroscopic studies using coarser resolution data sets have failed to identify these mafic signatures due to obscuration of the underlying material in addition to the relatively small scale exposures in impact craters the nature of the surficial obscuration material is likely multifaceted and includes the deposition of latitude dependent mantling material and the presence of alteration rinds this observation shows that the northern plains of mars are basaltic and must be factored into the thermal and surficial evolution of mars

stress regime strain release and geothermal implicationsregional stress field and rifting in western europe in situ stress determination is one possibility to determine stress magnitudes in the earth s crust most measurements especially in the northern alpine foreland have been carried out by using the doorstopper technique stress magnitudes are presented as excess stresses a number of sites where stresses have been determined gave sufficiently high values to statistically determine stress directions for the following tectonic blocks 1 1 western alps 2 2 their immediate foreland with the rhinegraben and 3 3 the rhenish shield bordering on the rift segment of the lower rhine embayment in discussing results of the statistical analyses of stress data it is suggested that stresses measured in the western alps have mainly a topographic origin in the alpine foreland to the north of the rhenish shield topographic stresses are superimposed on active tectonic stress considering the structural and lithological differences the foreland blocks show a different response to the same tectonic stress field which trends for 1 at about 146 this active stress field causes shear rifting in the upper rhinegraben but extensional rifting in the lower rhine embayment in the rhenish shield area only local step faults are observed in direction of 1 due to the ductile behaviour of its basement

rhinegraben horizontal stylolites indicating stress regimes of earlier stages of rifting abstract buchner f 1981 rhinegraben horizontal stylolites indicating stress regimes of earlier stages of rifting in j h illies editor mechanism of graben formation tectonophysics 73 113 118 tectonic stylolites horizontal columns and their statistical distribution in middle triassic and jurassic limestones on both flanks of the rhinegraben are described and their relation to the rhinegraben taphrogenesis is discussed a generation of pre middle miocene nne striking horizontal stylolites and a subsequent generation of post lower miocene nw striking horizontal stylolites have been recognized the first generation stylolites indicates a horizontal compression in the nne ssw direction while the second generation indicates a compression in the nw se direction average maxima of joints parallel to the two horizontal stylolite maxima were found joints and their corresponding horizontal stylolites were formed under the same stress regime

lateral and vertical changes of deformation style in the osen roa thrust sheet oslo region abstract changes in deformation style and amounts of shortening in the osen roa thrust sheet of the oslo region occur vertically and laterally approaching the thrust front in the south deformation in the cambromiddle ordovician sequence passes laterally from closely spaced imbricates in the north 50 60 shortening through triangle pop up and imbricate zones toward the south 20 37 shortening to widely spaced zones of deformation up to 20 shortening approaching the thrust front changes in deformation style are attributed to changing boundary conditions across the klekken thrust declining end of orogenic forces and an increase in thickness of competent units in the ordovician rocks to the south vertical changes in deformation style are attributed to the increasing percentage of competent units upward in the cambro silurian sedimentary rocks in the north the accompanying decrease in shortening upwards requires a structurally necessary upper detachment horizon to separate folded late middle ordovician silurian sediments from imbricated early cambro middle ordovician sediments below while southward in the oslo area the upper detachment needs to be placed between silurian and cambro ordovician units finally in eiker with less than 20 shortening the whole cambrosilurian sequence appears to have deformed as a single unit in the northern oslo region the upper detachment probably has a backthrust sense of motion above an imbricate stack passive roof duplex further south the upper detachment is probably directed toward the foreland

the neotectonics of the tibetan plateau part of the continuing northward convergence between india and eurasia is probably taken up by strike slip displacement with tibet as a whole moving eastward away from the collision zone and undergoing east west extension molnar and tapponnier 1975 ni and york 1978 on the basis of our interpretation of landsat images we propose that strike slip faulting occurs throughout the tibetan plateau such that its north south cross section is being shortened with little contemporary folding or thrusting

a balanced section across the pyrenean orogenic belt evolutionary models that have been proposed for the pyrenean orogenic belt involve gravitational gliding of major thrust sheets to both the north and south of an uplifted central axial zone it has been suggested by previous workers that uplift is a result of alpine compression or long lived strike slip movement on the north pyrenean fault we critically assess these models and propose a new model based on the generation of a thin skinned linked thrust system due to alpine collision of iberia and europe pyrenean alpine tectonics is dominated by southward thrusting on a major sole fault dipping north at approximately 6 within hercynian basement northerly directed thrusts of the north pyrenean zone and northern folded foreland are backthrusts from this sole fault a total orogenic shortening of 106 km in the central pyrenees was achieved between the palaeocene and oligocene at a time averaged rate of 0 62 cm yr 1 a thin skinned model requires that the north pyrenean fault is truncated by both northward and southward moving thrusts and occurs in the footwall of the sole fault some 60km north of its present surface trace

thrust fault mechanics and origin of a frontal ramp several features of thrust sheets in nonmetamorphic and relatively low grade metamorphic terrains indicate that the modes of faulting included both gradual and stick slip types of motion a first order quantitative analysis is made of the mechanics of this type of faulting in the analysis part of a wedge shaped thrust belt slips forward over a fault area of length l and unit width w producing a strain concentration in subhorizontal strata at the front of the growing thrust where a frontal ramp develops by shear fracturing equations for net slip x and the conditions for ramping are evaluated with limit equilibrium principles and coupled oscillator theory the quantitative analysis takes into account anisotropy resulting from contrasts in competency and facies changes a special case solution for maximum net slip associated with stick slip is lw ki 1 cos ot o 12 1 cos 1t where is the stress drop ki are spring constants of the strata 0 and 1 are natural frequencies of the system and t evaluated from another equation is the time for net slip the spring constants and natural frequencies can be evaluated from seismic and stratigraphic data a preliminary solution for piggy back thrusting indicates that ramp spacing can be systematic and that it depends upon the thickness of the deforming package the elastic parameters of the deforming package the slope of the topographic surface and the stresses along the trailing edge of the package

submillimeter scale topography of the lunar regolith we have applied computer stereophotogrammetry to apollo lunar surface closeup camera alscc pictures of the lunar surface to construct the first ever digital topographic relief maps of undisturbed lunar soil over spatial scales from 85 m to 8 5 cm using elevation histograms fractal analysis and hapke s photometric roughness model we show that apollo 14 fra mauro imbrium ejecta is rougher than average apollo 11 mare tranquilitatis and apollo 12 oceanus procellarum mare surfaces at submillimeter to decimeter size scales we confirm the early result of k lumme et al 1985 earth moon planets33 19 29 that the cumulative distribution of elevations for lunar soil is typically well described by gaussian statistics however cumulative distributions are insensitive to asymmetries in the shapes of elevation histograms of 11 discrete elevation histograms we measured about half exhibit significant deviations from gaussian behavior we also confirm lumme et al s finding that the roughnesses of all lunar surfaces increase with decreasing size scale we further show that the scale dependence of roughness is well represented by fractal statistics the rates of change of roughness with size scale represented by fractal dimension d are remarkably similar among terrians after correcting for the contribution of large scale roughness our average value of d 2 31 0 06 falls within the range 2 0 d 2 4 reported from lunar radar studies the amplitude of roughness which we characterize with the rms slope angle at 1 mm scale varies significantly among terrains for lunar mare the average rms slope angle is 16 4 3 and that for fra mauro regolith is 25 1 by comparison to radar data we suggest that the roughness of fra mauro imbrium ejecta regolith is similar to that of lunar highland terrains we find that the gaussian slope distribution assumed in b w hapke s model 1984 icarus59 41 59 adequately describes typical lunar regolith surfaces a revised form of hapke s equation that models realistic particle phase functions and the coherent backscatter opposition effect was fitted to disk resolved lunar photometric observations and yields estimates of 27 1 for highland and 24 1 for mare regolith these values of as well as the implied relative highland mare photometric roughness ratio are best matched in our elevation data by the cummulative contributions of surface topography covering all scales greater than 0 1 mm less than 5 of the photometrically detected roughness of lunar regolith is contributed by surface relief at scales larger than 8 cm this conclusion implies that values of derived from whole disk and disk resolved photometry respectively may be taken to represent the same physical quantity in addition particulate samples used in goniophotometric measurements should not be assumed to be photometrically smooth i e 0 as is often done in laboratory applications of hapke s photometric model the predicted photometric roughness at size scales of 0 1 mm and less significantly exceed photometric estimates and suggests that there exists a measurable size scale below which topographic relief either is not photometrically detectable or is not represented in the hapke model as macroscopic roughness

plate tectonics and the evolution of the british isles this paper is an essay on the rationalism and difficulties of the geological corollaries of plate tectonics with illustrations particularly from the geological history of the british isles there is special emphasis on the mechanics of continental lithosphere in extension when basins are formed and in convergence whereby continental lithosphere thinned in extension is shortened and restacked to form orogenic belts an upper lithosphere stress concentrating elastic lid suffers extremely complex inhomogeneous deformations above a simpler viscoelastic lower lithosphere whose deformation drives strain and displacement in the elastic lid the very nature of plate tectonics as relative motion among a multi plate mosaic of plates provides a rational semi quantitative framework for large scale geological complexity in space and time the caledonian and hercynian history of the british isles may be explained semi quantitatively in terms of plate boundary evolution but it is not possible to define unequivocal solutions the rationalism of plate tectonics is exhibited on a smaller more direct field scale by many of the complexities of ophiolite complexes such as ballantrae scotland that can be explained as the effects of the evolution of ridge ridge transforms and by diachronous deformation and sedimentation in subduction accretion prisms such as the southern uplands deformational and sedimentary patterns in nw europe from triassic times to the present day resulted from a complex interaction of extensional events related to diachronous atlantic opening and compressional events related to sequential alpine shortening phases those widespread events are typical of intracontinental plate boundary systems and create great difficulties for the geologist wishing to decipher relative plate motion from geological sequences because huge areas much larger than the british isles must be analysed and synthesized before much sense can be extracted further difficulties arise from the palinspastic and preservation problems of convergent boundaries orogenic shortening telescopes and partially subducts facies belts most orogenic belts were assembled as a collage of displaced and rotated terrain elements that were subsequently flattened elongated and straightened to an apparent but deceiving simplicity therefore while plate tectonics provides a rational geological framework against which for example british basin evolution can be tested and explained we cannot yet use the geological effects of plate boundary evolution to reconstruct relative plate motion quantitatively

styles of positive inversion tectonics in the central apennines and in the adriatic foreland implications for the evolution of the apennine chain italy abstract integration of new field structural and geophysical data with existing information from the apennines chain in italy and its adjacent adriatic foreland indicates that the styles of positive inversion tectonics and the modes of interaction between the extensional and the subsequent compressive structures vary starting from the cretaceous the contractional deformation induced by the mainly north directed convergence of africa adria with respect to the european plate promoted the closure of various arms of the atlantic and the neo tethys oceans which opened in different times and with distinct orientations the mosaic of continental blocks carbonate platforms rift basins and oceanic domains with several geometries and orientations with respect to the axis of the subsequent compression and the resulting heterogeneities within the shallow sedimentary cover and the overall lithosphere strongly influenced both the structural evolution of the apennine orogenic belt and the intra continental deformation within the adriatic foreland field observations reveal that the steeply e and w dipping mesozoic cenozoic normal faults are systematically decapitated by sub horizontal or gently west dipping thrusts propagating with short cut trajectories pre thrusting normal faults were commonly deformed by later thrusts but little evidence seems to support their entire reactivation as high angle reverse faults this suggests that these shallow and steeply dipping discontinuities were not suitable to be reutilized by the superficial thin skinned thrust faults propagating within the sedimentary cover in contrast presumably late paleozoic and mesozoic w dipping normal faults appear moderately reactivated in the adriatic foreland and strong positive inversion tectonics affect the deeper and buried structural levels of the apennine chain within the latter the syn rift sediments in the hangingwall blocks of the fault bounded basins were totally extruded and generated the strong uplift of the thinned adria continental crust finally the contrasting styles of interactions of the pre existing normal faults with later thrusts i e passive truncation or positive reactivation strictly result from the different evolution of the apennine chain and the combined thin and thick skinned modes of deformation of the stretched lithosphere of the adria plate

continental extension of the pacific plate at the southern termination of the hikurangi subduction zone the north mernoo fault zone offshore new zealand a complex transition from subduction at the hikurangi margin to transpressive continental collision across the southern alps occurs in the ne south island region of new zealand offshore the southern limit of oceanic subduction is constrained by the chatham rise a submerged continental plateau on the pacific plate which is presumably too buoyant for normal subduction in the nw corner of the rise is the north mernoo fault zone nmfz a 100 by 300 km region of basement involved active normal faulting of late miocene circa 8 6 ma to recent age the nmfz evolved contemporaneously with the rotation and development of the adjacent plate boundary zone growth faulting is characteristic within the sedimentary cover which is generally less than 2 km thick but the distribution of faulting has varied temporally the amount of mid pliocene recent extension is estimated to be not more than a few percent the nmfz consists of an array of overlapping south dipping normal faults which are typically 2 5 km apart and which trend roughly e w at a high angle to the plate boundary zone late quaternary surface traces are widely distributed on the mid to upper continental slope but many surface scarps are poorly preserved due to extensive erosion of the seafloor the western end of the fault zone crosses submarine canyons at the southern end of the hikurangi trough and almost abuts two fold and thrust fault systems on the ne south island continental margin although few data constrain the kinematics of extension a single mw 6 1 earth quake at the western end of the nmfz suggests planar rotating faults with a component of left lateral oblique slip two possible models of regional extension are considered 1 lateral buckling of the upper crust in which faulted slivers of crust are peeled off as the chatham rise slides past the transpressive marlborough fault system toward the southern alps and 2 flexure of the edge of continental pacific plate as the chatham rise is bent downward into the southern end of the hikurangi subduction zone improved seismological data and deep crustal seismic reflection profiles may help to constrain the kinematics of deformation

intraplate deformation and basin formation during the tertiary within the northern iberian plate origin and evolution of the almazan basin the tertiary almazan basin was a topographic high during the mesozoic rifting at the northern part of the iberian plate it was bordered by two mesozoic basins 1 the castilian basin with a maximum thickness of more than 2000 m to the south and 2 the cameros basin with a maximum thickness of 9000 m to the north to the east the almazan basin is bordered by paleozoic rocks of the nw se trending aragonian range which underwent little subsidence during the mesozoic the two mesozoic basins show an e w direction during the tertiary nne ssw compression mainly late eocene early miocene both mesozoic basins were inverted and uplifted and the almazan basin with an overall synclinal geometry was filled with syn tectonic terrestrial sediments reaching a maximum thickness of 3500 m deformation during the tertiary was strongly controlled by preexisting structures both mesozoic extensional faults and reactivated variscan folds the depocenter of the tertiary basin migrated southward during the paleogene this migration is consistent with a piggyback transport of the whole basin northward due to the movement on the underlying crustal scale north verging cameros thrust the geometry and sedimentary evolution of the almazan thick skinned piggyback basin was controlled by the uplift associated with the main crustal scale thrust which was the main source area and was separated from the foreland basin since the early stages of filling late eocene this makes the main difference with thin skinned piggyback basins controlled by the foreland thrust belt and separated from the foreland basin only at their late stages

a late cenozoic regional mesofracture system in southern england and northern france the upper cretaceous and palaeogene rocks of s england and n france are cut by a nw trending system of fractures characterized by swarms of vertical extension joints accompanied by conjugate sets of hybrid and shear joints and normal mesofaults many major photolineaments exhibit the same nw trend as the fractures and are particularly conspicuous in n france where they are coincident with rectilinear drainage channels suggesting a relationship between fracture orientation and physiography in s england this relationship is absent possibly because of the influence of additional fracture systems related to major flexures trending obliquely to the nw se direction these major e w trending flexures and associated fracture systems were formed during the oligocene to early miocene 9helvetic9 phase of deformation and are cross cut obliquely by fractures in the nw trending system the nw trending fractures and lineaments are parallel to neotectonic normal faults in the lower rhine embayment and become less well developed to the west with increasing distance from these major structures the lower rhine faults were reactivated and propagated into the quaternary cover as a consequence of ne sw regional tension generated during the late neogene to recent 9jura9 phase of nw se alpine convergence the nw trending extensional structures in s england and n france are considered to be of about the same age and related to the same stress regime as the neotectonic normal faults of the lower rhine embayment however because fractures of the nw system cutting palaeogene sediments in se england are truncated by the erosion surface beneath the plio pleistocene red crag deposits it is possible that in england fracture initiation did not continue into quaternary times

topographic lineament swarms clues to their origin from domain analysis of italy regional scale subparallel linear topographic features characterize almost all planetary surfaces this experiment concerns their tectonic meaning by focusing on map limits or domains through which individual swarms of these linear features are developed these domain limits are contrasted with map boundaries of better known structural features in a tectonically active region italy to seek clues to stress environments and times of origin of the lineaments the study uses regional raised relief maps to filter the lineament data to a very simple subset those strictly topographic features of a length and prominence capable of retaining detectability through generalizations required by relief map production a total of 5 372 lineaments were drawn using 4 differently lighted images of 1 1 000 000 scale relief maps of italy seven different tests were used for reliability and reproducibility of the data rose diagrams were prepared for 86 subareas by computer fitting of gaussians to azimuth frequency histograms individual azimuthal petals of these roses were then correlated to delimit the general area over which a given azimuthal swarm is developed the precise swarm boundaries were then located by computer contouring the population density of lines of each swarm on the original data set in this way 48 local swarms were mapped boundaries of these swarms correlate poorly with traditional litho tectonic provinces instead they seem to be associated with basin axes broad arches coastal flexures areas of normal fault swarms and projections of structural grain from adjacent sea floors the 48 domains may be grouped into 8 noncontiguous but azimuthally compatible super swarms covering much of italy the most prominent of the super swarms are greatly expanded versions of regional structural grains trend of the po basin axis of the upper adriatic basin zone of south alpine underthrusting and landward extensions of structural grain of the tyrrhenian sea from these relationships a model for lineament swarm origins is proposed involving very minor regional stretching of the thin brittle carapace of extremely large sometimes subtle structures deforming by ductile mechanisms at depth

geologic evolution of the pena flexure southwestern pyrenees mountain front spain abstract the sedimentary and tectonic evolution of oligocene continental growth strata of the pena flexure records the development of a thrust related anticlinorium and foreland dipping molasse along the southwestern pyrenees mountain front we exploit the coupling of uplift the production of accommodation space and resultant synorogenic sedimentation to explore the interplay of processes accompanying thrust faulting a new magnetic polarity strata through 3400 m of continuous pre and syn growth strata near the town of sos del rey catolico spain shows coordinated deposition and deformation the chrm data reside mostly in magnetite correlation to the geomagnetic polarity time scale suggests our measured stratigraphic section spans from 33 2 ma chron c12r in the middle campodarbe formation to 23 4 ma chron c6c at the top of the bernues formation shallowing in dip of the growth strata up section is related to coeval slip on a mountain front backthrust the onset of growth strata deposition and fault slip at this position along the pyrenees mountain front occurred at about 28 6 0 1 ma folding rates calculated from the growth strata at the resolution of the polarity chrons 0 15 1 12 myr varies from 03 myr to 35 myr

local topographic effects on photometry and reflectance spectra of planetary surfaces an example based on lunar photometry the photometric properties of the average lunar surface are characterized using hapkes equations and whole disk observations ranging from 0 36 to 1 06 m synthetic spectra across a crater topographic profile arecreated using the modeling results the synthetic spectra are examined for spectral variations created by changes in lighting conditions induced by the topography changes above the modeling uncertainties are seen in both spectral slope and band depths though the most pronounced change is in band depth the data have insufficient spectral resolution to determine if there are any changes in band center due to photometric effects no additional absorption features are introduced by the photometry these results have serious implications on the interpretation of spectral observations in terms of abundance estimates and alteration processes as a function of location and association with geologic features

field evidence for active normal faulting in tibet crustal thickening does not now occur in southern tibet field observations made during the chinese french expedition of 1980 support an earlier hypothesis based on a combined analysis of satellite images and fault plane solutions of earthquakes immediately north of the highest peaks of the himalayas the tectonic regime is dominated by east west extension we have mapped a large number of north south normal faults which sharply cut the glacial and post glacial morphology and followed several recent earthquake breaks along faults detected on satellite and aerial photographs microtectonic measurements in the quaternary suggest that the maximum principal stress is vertical

thrusting and gravel progradation in foreland basins a test of post thrusting gravel dispersal the use of gravels as syntectonic indicators of thrusting has recently been questioned by foreland basin models that assign gravels to a post thrusting interval of progradation except in very proximal areas on the basis of precise temporal control provided by magnetostratigraphically dated sections the history of gravel progradation after a major thrusting and uplift event in the northwestern himalaya is shown to be a virtually syntectonic phenomenon despite considerable crustal subsidence driven by a thick skinned thrust gravels prograded approximately 70 km during a 1 5 m y long thrusting event by 3 m y after the start of thrusting gravels extended more than 110 km into the basin although delayed gravel progradation appears appropriate for many rocky mountain foreland basins it is clearly not valid for the himalaya the authors attribute the difference in depositional response between these basins to difference in the quantity of sediment supplied to them sediment starved vs overfilled the availability of resistates in the source area and the size of the antecedent drainage

characteristic microseismicity during the development process of intermittent rockburst in a deep railway tunnel abstract during deep tunnel excavation more than one rockburst sometimes occur in a particular area which seriously threatens construction safety in this work the characteristic microseismicity occurring during the development process of intermittent rockburst more than one rockburst occurring in a particular area and single rockburst only one rockburst occurring in a particular area and the associated mechanism of formation are studied data was collected during the construction of a railway tunnel in southwestern china microseismicity was recorded and analyzed before and after each rockburst for both intermittent and single rockbursts the schmidt number declines heavily with time the cumulative apparent volume rises sharply with time and the seismic activity is high before the rockburst however this characteristic microseismicity can also be found with no rockburst occurrence between each rockburst in an intermittent rockburst the ms events mostly have low ms energy i e whose logarithm measured in joules is smaller than 3 5 and the energy stored in the rockmass of the rockburst zone is not adequately released therefore there is likely to be another rockburst after the blast when high in situ stress is present after the last rockburst of an intermittent rockburst and the single rockburst some ms events of high ms energy i e whose logarithm measured in joules is larger than 3 5 occur in the deep surrounding rockmass and the energy stored in the rockmass of the rockburst zone is gradually released to a certain degree the stress is transferred to the deep surrounding rockmass whose stability is relatively high as a result a subsequent rockburst is hardly likely to occur again

late cretaceous and early miocene andean type plutonic activity in northern makran and central iran two calc alkaline plutonic complexes bazman and natanz intruded through the south eastern active and south western ancient continental margins of central iran have been dated by the rb sr whole rock isochron method at 74 2 and 24 4 5 ma respectively detailed trace element studies together with low 87 sr 86 sr initial ratios 87 sr 86 sr ratios and the gabbros at least were intruded some 10 ma earlier

integrated analysis for constraining palaeoclimatic and volcanic influences on clay mineral assemblages in orogenic basins palaeogene andean foreland northwestern argentina abstract variations in clay mineral assemblages in ancient continental deposits are frequently used to reconstruct past climate changes in active settings volcanic events can supply highly labile volcaniclastic material which can easily be transformed into smectite via diagenesis which can produce a noticeable footprint in clay mineral assemblages southern central andean foreland deposits are appropriate case studies to ascertain whether the climatic signal was preserved in the clay assemblages of their fine grained sediments as tectonic uplift volcanism and sedimentation have been interacting since the cretaceous we have studied a 1400 m thick coarsening upward palaeogene succession of the tin tin basin northern calchaqui valley argentina applying x ray diffraction xrd electron microscopy and detailed sedimentary facies analysis with the aim of comparing tendencies in the vertical fluctuations of clay minerals with evidence from sedimentological facies illite muscovite plus smectite account for 78 to 100 of the clay minerals in the fine fraction with kaolinite and chlorite in subordinate amounts the vertical variation of sedimentary settings from an overbank lacustrine domain to fluvial braided plains and an aeolian dune field suggests a gradual increase in aridity upsection however smectite abundances do not show a gradual decreasing trend compatible with progressively lower hydrolyzing conditions their relative abundances vary widely throughout the section depicting pulse like abrupt fluctuations despite the absence of field evidence for volcanic influence several indications of volcanic and volcaniclastic material have been found under scanning electron microscopy sem in levels with high smectite abundances from the middle to the top of the succession they include quartz crystals showing embayments and skeletal forms with smectite filling the voids microcrystalline silica as well as heulandite crystals in close association with authigenic smectite the xrd analyses of these levels evidence well crystallized smectite which is characteristic of a volcaniclastic origin therefore the increase in smectite abundance in these beds reflects a significant volcaniclastic contribution which is also evidenced by a centimetre thick ash layer topward in the sequence the only smectite rich level near the base of the tin tin section also contains well crystallized smectite associated with heulandite thus probably evidencing volcaniclastic input we infer that most of the smectite in these sediments formed during early diagenesis probably through the dissolution of labile tuffaceous material textural and morphological analysis by sem is essential to determine whether clay mineral assemblages could be interpreted in terms of palaeoclimate

evaluation and application of controlling parameters for seismic events in hard rock mines a method is proposed for quantitative assessment and interpretation of the seismic hazard of planned excavation in a hard rock mine the quantitative assessment is derived from three dimensional elastic boundary element modelling of the host rock mass parameters obtained from the modelling are associated with historical observations of seismicity in the mine to generate probabilistic relations between seismic event occurrence and event strength the parameters used in the event spatial occurrence relations and the event strength estimates are the factor of safety against seismic failure for different types of seismic events which are inferred from back analysis of field observations and the modelled ground work the estimates of these parameters are related to the controlling quantities for a seismic event which are a local state of stress sufficient to cause rock mass failure and an unstable local concentration of strain energy i e energy in excess of that which can be dissipated non violently in rock mass failure application of the method is illustrated by reference to several case studies of mine seismicity

isochronous fluvial systems in miocene deposits of northern pakistan a palacomagnetic isochron dated at about 8 1 myr bp and detailed lithostratigraph of a 40 m interval exposed along strike for 40 km establish the depositional patterns of two contemporaneous interfingering fluvial systems in the upper part of the meddle siwalik sequence the two systems referred to as the buff and blue grey differ in unit shape lithofacies bedding sequence palaeocurrent direction and sand composition interfingering occurs along the south west north east strike of the outcrops with the palaeodrainage directions of the two systems generally perpendicular to this line the axis of the blue grey system which deposited widespread sheet sands and silts lay toward the south west end of the study area the more complex axis of the buff system which deposited shoe string sand bodies and lage volumes of silt and clay lay toward the north east the source area for both systems was the rising himalyan belt to the north and noth east of the study area at maximum extent the blue grey system occupied a channel belt at least 25 km wide channel belt widths and depths for the buff system are 1 3 km and 3 7 m respectively current directions averge 94 for blue grey sands and 136 for buff sands blur grey sands contain 20 more rock fragments and are otherwise less mature than buff sands the buff system shows a verticla pattern of avulsion palaeosol formation and floodplain aggradation which we attribute to autocyclic processes of parallel rivers the blue grey system shows phases of erosion accompaniced laterally by plaeosol formation folowed by valley fill and overfowing of interfluve surfaces theis pattern may be caused by allocyclic presses affecting the source area we interpret the blue grey system as a major drainage from the interior himalayas perhaps the ancestral indus and the buff system as a complex of smaller drinages along the mountain front which were probably ributaries to the bluegrey syste vertebrate fossils including hominoid primates from the area are almost exclusively associated with lithofacies of the buff system and this probably refects both taphonomic and palaeoecological differences between the two systems

rockburst mechanism and prediction based on microseismic monitoring abstract in this study the rockburst definition is comprehensively described and several main rockburst theories the strength theory the energy theory the bursting liability theory the rigidity theory and the instability theory are analyzed the two body interaction theory based on the newton s law can explain the rockburst mechanism most reasonably the rockburst development process is a static process and the rockburst occurrence process is within the scope of dynamics in addition some precursors exist before rockburst occurrence reflected by the consistency between acoustic emissions and damage variables in rock mass which can be summarised as three seismogenic models according to the tempo spatial distribution by utilizing the 3s stress buildup stress shadow and stress transfer principle in seismology three rockburst criteria are proposed in this paper namely the stress tempo spatial evolution the magnitude energy and concentration degree of microseismic events sudden change of apparent volume finally by comparing the results obtained by microseismic monitoring and landsonar positioning it is shown that the root cause of rockburst occurrence is rock heterogeneity and the existence of joints and fractures the fracture intersection points are the locations for rockburst initiation it is proven that the two body interaction principle can perfectly explain the rockburst mechanism

the scattering properties of natural terrestrial snows versus icy satellite surfaces abstract a j verbiscer and j veverka 1990 icarus 88 418 428 demonstrated that the single scattering properties of terrestrial snows are highly forward scattering in contrast to the single scattering properties of icy satellite surfaces which all have a backscattering component to their single scattering functions as modeled with b hapke s equations 1981 j geophys res 86 3039 3054 1984 icarus 59 41 59 1986 icarus 67 264 280 this study demonstrates to first order that the differences between the scattering properties of icy satellite regoliths and their terrestrial counterparts are due to differences in particle structure and textures we find that the particles of the regoliths of the icy satellites are composed of a complex mixture of grain textures and structures

evolution of a turbiditic foreland basin and analogy with an accretionary prism example of the eocene south pyrenean basin the south pyrenean tertiary basin was an east west trending foreland trough which developed from early eocene to miocene times in a north south trending compressive regime a turbiditic series of lower and middle eocene age hecho group enables us to define the typical features of the tectono sedimentary evolution of the basin 1 slope and shelf derived carbonate turbidites and megaturbidites bear witness to the seismic activity of the basin borders 2 the southern basin border evidenced by the onlap of the turbidites onto slope and shelf deposits migrated progressively southwards in time and 3 the deformation pattern is characterized in the meso cenozoic sediments by a complex thrust fold system of thin skinned tectonics style its specific geometry and kinematics were influenced by the pre deformation geometry onlap this thrust fold system is related to south directed basement nappes and its front advanced progressively southwards in time from this data we infer an evolutionary model for this highly mobile basin it was a flexural basin linked to the northward bending of the lithosphere in the foreland of a south directed crustal accretionary prism as the nappes advanced the basin migrated progressively southwards in the foreland direction as for the actual basin evolution many analogies with accretionary prism trench systems of active margins exist

evolving alluvial stratigraphy and thrust front development in the west jaca piggyback basin spanish pyrenees in the southwestern pyrenees distinctive alluvial mega sequences correlate with the development of a shallow mountain front thrust structure the pena flexure the flexure evolved during the oligocene to early miocene and is interpreted as a duplex marking the limit of thrust front advance three main depositional facies preserved completely across the pena flexure are described a pre thrust emergence high sinuosity fluvial sequence the c 2300 m thick sheet sandstone facies of the campodarbe formation a syn thrust emergence conglomeratic alluvial fan sequence the c 1100 m thick conglomeratic facies of the bernues formation and a post thrust emergence low sinuosity fluvial sequence the 700 m thick ribbon sandstone facies of the uncastillo formation collectively their continuous exposure across the pena flexure provides a more or less complete record of the sedimentary evolution of a mountain front syn deformational features in the alluvial fan sequence of the bernues formation and marked contrasts in palaeochannel morphology sandstone body geometry and palaeocurrent patterns between the two fluvial sequences are best understood by invoking a strong tectonic control over their deposition an increased rate of vertical sediment accretion was a key process in determining fluvial style the onset of major thrusting led to more rapid basin floor subsidence thereby promoting a change from lateral to vertical accretion as channels responded to the rising base level

sandy high energy flood sedimentation some criteria for recognition with an example from the devonian of s w england abstract many modern sand deposits resulting from episodic floods in semi arid zones are dominated by parallel laminations but parallel laminated sands are not a major feature in perennial streams single flood events may deposit over 1 5 m of parallel laminated sand hence ancient parallel laminated sand dominated alluvial deposits may be the product of ephemeral flows the trentishoe formation hangman sandstone group middle devonian of north devon consists in part of laterally extensive beds of parallel laminated fine grained red sandstones that build multistorey sand bodies individual beds are little more than 1 m thick but may extend laterally for hundreds of metres a vertical sequence of erosion surface sparse silt clasts parallel laminations silt drape is often found suggesting high flow stage deposition of plane bedded sand followed by a very rapid waning of flow with silt fallout in the final stages of the flood this sequence bears marked similarity to certain modern ephemeral flow sands

the west european stress field new data and interpretation abstract the mapped stress field of western europe reflects the tectonic process active there a traverse of stress measurements from the alps and through their northern foreland to the southern border of the lower rhine embayment identifies three distinct stress sub provinces the western alps the blocks on both flanks of the rhinegraben and the rhenish shield the alps have high magnitude stresses up to 35 mpa in the direction of maximum compression here called 1 h the general direction of 1 h is about 140 the foreland has the same directional trend of 1 h with a magnitude reduced to about 2 0 mpa local anomalies in magnitude and direction occur along the course of the rhinegraben which is a site of active sinistral shear the rhenish shield shows an internal zonation of the stress field the magnitudes of the stresses are low usually negative along the axis connecting the northern end of the rhinegraben with the rifting of the lower rhine embayment the direction there is about 150 on the eastern and western flanks of the shield the stress directions are essentially the same as in the southern blocks these zones are distant from the belt of active strain release consequently stresses of up to 4 0 mpa have accumulated

thrust tectonics in the south central pyrenees abstract surface structural data and published stratigraphies are combined to construct two balanced and restored sections through the nogueras zone of the south central pyrenees the allochthonous nogueras zone units are interpreted as the foreland dipping margin of a major antiformal stack in the palaeozoic rocks of the pyrenean axial zone their structural evolution is summarized in a hangingwall sequence diagram this reinterpretation of the nogueras zone is incorporated into a new n s balanced and restored section from the centre of the pyrenean axial zone to the ebro basin a classical rocky mountains piggy back thrust model is employed and the resulting section is a significant departure from those previously published it is argued that gravity gliding has never been an important mechanism in the alpine pyrenees section restoration casts doubt on the correlation of the surface expression of the north pyrenean fault and the seismically detected moho step beneath it

the functioning of sediment routing systems using a mass balance approach example from the eocene of the southern pyrenees abstractsediment routing systems link source regions undergoing erosion with depositional sinks and involve a volumetric or mass budget understanding how these source to sink systems function is key to stratigraphic prediction but estimation of their surface sediment discharges and depositional fluxes on geological time scales is a challenging problem we recognize a paleosediment routing system from the geological record in the mid late eocene escanilla formation and time equivalents of the tectonically active wedge top region of the southern pyrenees by mapping the 200 km long fairway of the escanilla sediment routing system we obtain the sediment budget and grain size fractionation of three time intervals each of 2 5 2 6 m yr duration over the time period 41 6 33 9 ma four thousand cubic kilometers of sediment sourced principally from two feeder systems in the high pyrenees was deposited in a period of 7 7 m yr the positions of moving boundaries characterized by rapid reduction in the perc

passive roof duplex geometry in the frontal structures of the kirthar and sulaiman mountain belts pakistan abstract exploration for hydrocarbons over the past few years has greatly improved our understanding of the geometry of frontal mountain belt structures in this study we introduce and discuss the concept of the passive roof duplex using as the main example the kirthar and sulaiman ranges in the baluchistan province of pakistan structures similar to those described here have been recognized previously in other mountain belts and they appear to exist as a common feature in many more frontal regions of mountain belts our example of a passive roof duplex which we describe from pakistan is compared briefly with similar structures reported by others the passive roof duplex is here defined as a duplex whose roof thrust has backthrust sense passive roof thrust and whose roof sequence those rocks lying above the roof thrust remains relatively stationary during foreland directed piggy back style propagation of horses within the duplex

clastic dike swarms and the structural evolution of the foreland fold and thrust belt of the southern andes clastic dike swarms are intruded into a cenozoic foreland fold and thrust belt in southern chile the dike material consists of sandstone and conglomerate with clasts as much as 25 cm in diameter brecciated wall rocks are also found in the clastic matrix the dikes often exceed 50 cm in width and hundred of metres in length in outcrop and are oriented overwhelmingly transverse to fold axes and parallel to cross joints the dike swarms are concentrated near the toe of major thrusts where they are found injected into the hanging wall a regional axial planar spaced cleavage is developed in the clastic dikes and sills clearly postdating injection of clastic material dike injection postdates at least the initiation of extension fractures the cross joint set within the swarms the dike intrusions represent as much as 20 extension parallel to fold axes in addition to several percent extension represented regionally by the cross joints the structural features of the dike swarms and their geometric relationship to other structures suggest rapid single phase injection the arrival of the front edge of a thrust on an already highly overpressured sedimentary sequence would cause an instantaneous increase in the overburden pressure and therefore could result in injection of a dense slurry of wet coarse sediments along preexisting planes of weakness field relationships of mesoscopic structures suggest the following evolution cross joint development incipient cleavage development initiation of thrusting and buckling clastic dike injection regional spaced cleavage development and associated late stage tightening of folds

mineralogy of the lunar crust results from clementine received 1997 december 5 accepted in revised form 1998 september 15 abstract the central peaks of 109 impact craters across the moon are examined with clementine ultraviolet visible uvvis camera multispectral data the craters range in diameter from 40 to 180 km and are believed to have exhumed material from 5 30 km beneath the surface to form the peaks including both upper and lower crustal rocks depending on whether craters have impacted into highlands or basins representative five color spectra from spectrally and spatially distinct areas within the peaks are classified using spectral parameters including key ratio which is related to mafic mineral abundance and spectral curvature linked to absorption band shape which distinguishes between low and high ca pyroxene and olivine the spectral parameters are correlated to mineralogical abundances related in turn to highland plutonic rock compositions the derived rock compositions for the various central peaks are presented in a global map from these results it is evident that the lunar crust is compositionally diverse both globally and at local 100 m scales found within individual sets of central peaks although the central peaks compositions imply a crust that is generally consistent with previous models of crustal structure they also indicate a more anorthositic crust than generally assumed with a bulk plagioclase content of 8 1 evolving from pure anorthosite near the surface towards more mafic low ca pyroxene rich compositions with depth comparable to anorthositic norite evidence for mafic plutons occurs in both highlands and basins and represent all mafic highland rock types however the lower crust is more compositionally diverse than the highlands with both a greater range of rock types and more diversity within individual sets of central peaks

active tectonics of the alpine himalayan belt between western turkey and pakistan summary over 80 new fault plane solutions combined with satellite imagery as well as both modern and historical observations of earthquake faulting are used to investigate the active tectonics of the middle east between western turkey and pakistan the deformation of the western part of this region is dominated by the movement of continental material laterally away from the lake van region in eastern turkey this movement helps to avoid crustal thickening in the van region and allows some of the shortening between arabia and eurasia to be taken up by the thrusting of continental material over oceanic type basement in the southern caspian mediterranean makran and black sea thus central turkey bounded by the north and east anatolian strike slip faults is moving west from the van region and overrides the eastern mediterranean at two intermediate depth seismic zones one extending between antalya bay and southern cyprus and the other further west in the hellenic trench the motion of northern iran eastwards from the van region is achieved mainly by a conjugate system of strike slip faults and leads to the low angle thrusting of iran over the southern caspian sea the seismicity of the caucasus shows predominantly shortening perpendicular to the regional strike but there is also some minor elongation along the strike of the belt as the causcasus overrides the caspian and black seas the deformation of the eastern part of this region is dominated by the shortening of iran against the stable borders of turkmenistan and afghanistan the north east direction of compression seen in zagros is also seen in north east iran and the kopet dag where the shortening is taken up by a combination of strike slip and thrust faulting large structural as well as palaeomagnetic rotations are likely to have occurred in ne iran as a result of this style of deformation north south strike slip faults in southern iran allow some movement of material away from the collision zone in ne iran towards the makran subduction zone where genuinely intermediate depth seismicity is seen within this broad deforming belt large areas such as central turkey nw iran azerbaijan central iran and the southern caspian appear to be almost aseismic and therefore to behave as relatively rigid blocks surrounded by active belts 200 300 km wide the motion of these blocks can usefully be described by poles of rotation the poles presented in this paper predict motions consistent with those observed and also predict the opening of the gulf of iskenderun ne of cyprus the change within the zagros mountains from strike slip faulting in the nw to intense thrusting in the se and the relatively feeble seismicity in se iran baluchistan this description also explains why the north south structures along the iran afghanistan border do not cut the east west ranges of the makran within the active belts surrounding the relatively aseismic blocks a continuum approach is needed for a description of the deformation even though motions at the surface may be concentrated on faults the evolution of fault systems within the active zones is controlled by geometric constraints such as the requirement that simultaneously active faults do not in general intersect many of the active processes discussed in this paper particularly large scale rotations and lateral movement along the regional strike are likely to have caused substantial complexities in older mountain belts and should be accounted for in any reconstructions of them

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

braided stream and flood plain architecture the rio vero formation spanish pyrenees early to middle miocene fluvial sandstones of the rio vero formation were studied in an area around the town of barbastro south central pyrenees spain the outstanding quality of outcrops in this area allows a three dimensional study of architectural elements six architectural elements are recognised described in detail and interpreted from three key localities seven main lithofacies were identified and sub divided into gravelly sandy and fine grained lithofacies the architectural elements and lithofacies have been combined with a hierarchy of depositional bounding surfaces to fully interpret the evolution of the depositional system at the meso and macro scale not only the different architectural elements and lithofacies of the complete braided fluvial system but also the lateral variation of the architectural elements were emphasised in this study differential tectonic movements seasonal climate change and their effect on vertical and lateral evolution of the area were the main control on basin sedimentation channel interconnection palaeocurrent patterns and consequently the fluvial architecture the presence of lateral ramp anticlines caused the fluvial system to be laterally restricted with the main channel belts being located in the areas of highest subsidence and lowest topography intervening topographic highs acted as both flood plains and lateral barriers between the main channel systems the proposed depositional model comprises broad low sinuosity perennial but seasonal moderate energy streams the sandstone architecture is dominated by channel fill and sheet sands and associated simple and more complex bars adjacent to the main channel belts fine grained sandstones siltstones and immature paleosols occur the along strike relationship between major fluvial systems and their outlets into a foreland basin has important implications for the infill of the basin and the modelling of fluvial systems along mountain belt fronts

structural and stratigraphic evolution of the west jaca thrust top basin spanish pyrenees thrust top basins form and fill during their detachment from the foreland margin by active thrust sheets strike normal n s sections from the west jaca thrust top basin southwest pyrenees to the ebro basin show that the pena flexure the local expression of the thrust front can be interpreted as a passive roof duplex the duplex accommodated up to 7 km bulk shortening at the tip of the gavarnie thrust sheet unravelling the timing of uplift and sedimentation in the west jaca basin has revealed that development of the pena flexure represented the climactic phase of deformation lateral e w diachroneity of gross stratigraphy and thrust emergence throughout the southwest pyrenees suggests that the thrust front propagated both toward the foreland and westward parallel to the orogen axis

constraints on the age of movement of the montsech and cotiella thrusts south central pyrenees spain palaeocene to oligocene thrusting in the pyrenees was synchronous with the development of the south pyrenean foreland basin collectively the tremp graus ainsa and jaca basins sedimentological and stratigraphical evidence from the foreland basin is used to constrain the age of movement of the montsech cotiella and external sierras thrusts movement on the emergent imbricate fan at the montsech front began in the early eocene illerdian during an early phase of thrusting that detached in the triassic evaporites in that region this phase of thrusting defined the tremp graus basin as a thrust sheet top basin following the early thrusting cuisian age tectonics in the tremp graus and ainsa basins was dominated by minor normal fault movements during flexural subsidence associated with thrust sheet loading growth of the boltana anticline to the west of the ainsa basin indicates that the ainsa basin had become detached as a thrust sheet top basin in the lutetian movement on the pena montanesa thrust and by inference on the cotiella thrust began in post lutetian times during the propagation of lower thrusts that involved pre triassic variscan basement thrusting in the external sierras caused folding and faulting of oligocene sediments indicating the continued southward propagation of basement involved thrusts in the upper eocene and oligocene many faults in the southern pyrenees have evidence of early normal and later reverse senses of movement indicating reactivation of normal faults during thrusting

the tibetan side of the india eurasia collision results are reported from the 1980 joint french chinese field expedition in tibet the area covered was from the high himalaya in the south to the region of nagqu 250 km north of yangbajain ophiolites in the zangbo valley represent remnants of the crust of an ocean basin which lay adjacent to the gangdise granodiorite belt in the late mesozoic the ophiolites were thrust to the south onto the cretaceous melange and triassic flysch but the age of this event is unclear in the tertiary sediments of the indian margin and the xigaze basin were folded with steeply dipping cleavage which indicates some north south shortening of the crust however the tertiary volcanic sequence on the lhasa block and further north shows comparatively little folding and thrusting in the quaternary deformation of tibet was characterized by east west extension

regional joint sets in the arabian platform as indicators of intraplate processes the eastern part of the saudi arabian craton is a platform underlain by gently tilted and horizontal mesozoic cenozoic sedimentary rocks everywhere more than 250 km distant from the zagros deformation front despite its tectonic simplicity the platform contains several laterally extensive but subdued structures and lineaments belonging to more than one system of fault zones and flexures new microtectonic observations of dominant sets of extension and conjugate hybrid joints permit regionally significant extension directions to be inferred and the origin of the macrostructures to be assessed the central arabian arch the e w crest of which coincides with an axis of mesozoic subsidence developed during the late cretaceous to eocene when the basin inverted as a consequence of the emplacement of ophiolite bearing nappes on the zagros and oman margins during arching there was strike parallel elongation of beds at the same time as the arch amplified the central arabian graben system evolved as a result of the northward displacement of an east arabian block or sheet that became detached across an arcuate separation zone which in the south is coincident with the crest of the arch an important neogene response in the arabian platform to ne sw shortening in the zagros ranges was the formation of a swarm of ne striking master joints and lineaments these structures reflect the diffuse and peripheral expansion of the foreland beyond the zagros deformation front

intracontinental wedging and post orogenic collapse in the mesohellenic trough the mesohellenic trough is a 130 km long and about 30 km wide subsiding area which contains a thick sequence of well exposed late cenozoic post orogenic sediments this intermontane basin located at the contact between the apulian and pelagonian collided margins provides a good example of the characteristics needed to study the chronology of late orogenic intracontinental structures

the foreland deformation in the south western basque cantabrian belt spain abstract in the south western portion of the cenozoic basque cantabrian belt structural data collected in pre orogenic upper cretaceous limestones were combined with aerial images interpretation in flat lying areas observations about fracture strike type orientation and overprinting relationships both at the macro and mesoscales allow to constrain the pre thrusting and pre folding deformational sequence that affected the area when it was forming part of the foreland basin wnw ese striking extensional structures represent the oldest elements developed during the very late stages of the mesozoic rifting associated with the opening of the bay of biscay the onset of convergence is marked by the development of extensional structures striking roughly nnw sse and wsw ene which are associated with belt parallel stretching in the foredeep and outer arc extension in the peripheral bulge respectively and developed in a non fluid assisted environment these elements are postdated by a pre folding layer parallel shortening pattern which includes wsw ene striking pressure solution cleavages and reverse faults both of them frequently reactivating inherited early orogenic wsw ene striking extensional elements and right lateral reactivation of wnw ese striking pre orogenic extensional structures this stage was followed by a syn to post folding e w oriented belt parallel compression wnw ese striking left lateral faults being the most outstanding elements associated with this stage the presence of such elements in upper cretaceous sediments provides support to the idea that left lateral shear zones of the area related with a cenozoic intrabelt lateral extrusion tectonics our results indicate coherently with previously published works in the pyrenean orogen that most of the mesoscale deformation has been acquired before layer s tilting

stratigraphy and static connectivity of braided fluvial deposits of the lower escanilla formation south central pyrenees spain this study addressed the architecture and dimension distributions of fluvial deposits of the olson member of the escanilla formation through analysis of outcrops in the southern buil syncline ainsa basin south central pyrenees spain the olson member consists of wide multistory channels alternating with mud rich intervals composed of flood plain deposits and isolated individual channels field descriptions and a combination of terrestrial light detection and ranging data and digital orthophotographs were used to map and document the abundance distribution and dimensions of sandstone bodies these data show that channels are distributed according to the local stratigraphic framework and differential subsiding areas morphology width depth and sinuosity of the channels throughout the sequence evolve according to their stratigraphic position during low accommodation periods channels stacked laterally forming wide multistory channel belts under these conditions single channels have a mean width to thickness w t ratio of 49 during high accommodation periods single channels have a mean w t ratio of 29 moreover the tendency of narrower and thicker channels having developed during high accommodation periods is also clearly observable vertically from the base to the top of high accommodation intervals throughout the sequence this pattern of deposition results in increasing vertical connectivity even in mud rich high accommodation periods a geocellular three dimensional model has been performed using object based simulations a succession of stochastic simulations was performed from the simplest one random simulations to more elaborated simulations integrating successively outcrop observations these simulations serve to image sandstone bodies connectivity evolution according to outcrop observations and sedimentologic knowledge subsurface application of such vertical channel morphology evolutions and distribution could lead to more predictive flow unit definitions and extensions

multispectral photometry of the moon and absolute calibration of the clementine uv vis camera abstract we present a multispectral photometric study of the moon between solar phase angles of 0 and 85 using clementine images obtained between 0 4 and 1 0 m we produce a comprehensive study of the lunar surface containing the following results 1 empirical photometric functions for the spectral range and viewing and illumination geometries mentioned 2 photometric modeling that derives the physical properties of the upper regolith and includes a detailed study of the causes for the lunar opposition surge 3 an absolute calibration of the clementine uv vis camera the calibration procedure given on the clementine calibration web site produces reflectances relative to a halon standard and further appear significantly higher than those seen in groundbased observations by comparing clementine observations with prior groundbased observations of 15 sites on the moon we have determined a good absolute calibration of the clementine uv vis camera a correction factor of 0 532 has been determined to convert the web site www planetary brown edu clementine calibration html reflectances to absolute values from the calibrated data we calculate empirical phase functions useful for performing photometric corrections to observations of the moon between solar phase angles of 0 and 85 and in the spectral range 0 4 to 1 0 m finally the calibrated data is used to fit a version of hapke s photometric model modified to incorporate a new formulation developed in this paper of the lunar opposition surge which includes coherent backscatter recent studies of the lunar opposition effect have yielded contradictory results as to the mechanism responsible shadow hiding coherent backscatter or both we find that most of the surge can be explained by shadow hiding with a halfwidth of 8 however for the brightest regions the highlands at 0 75 1 0 m a small additional narrow component halfwidth of

sedimentary basins formed and carried piggyback on active thrust sheets small sedimentary basins that formed on the apennine southern margin of the po basin complex northern italy have been studied using borehole and seismic reflection information and their evolution can be dated using the largely marine biostratigraphy of the miocene to quaternary sediments these studies show that the basins formed and were filled while being carried on moving thrust sheets and they are therefore named piggyback basins each of these basins corresponds to the active phase of a different thrust front ramp on the pyrenean northern margin of the ebro basin complex northern spain similar piggyback basins formed between eocene and mid miocene time they have since been uplifted and eroded and may therefore be studied in outcrop in northern spain much of the basin fill sediment was deposited in nonmarine environments

the structure of mountain fronts commonly the part of a mountain front which is visible at the surface consists of foreland dipping thrust belt rocks elevated above their regional structural position and overlain more or less conformably by molasse several explanations for their geometry are possible 1 major detachments exist within or beneath the molasse resulting in transport of the foreland basin examples of this geometry come from the swiss molasse plain the southern pyrenees and the mackenzie mountains of canada 2 displacement is lost on major backthrusts beneath the frontal monocline examples cited here are the rockies of alberta the sulaiman ranges of pakistan the mackenzies and the andes in peru 3 thrust sheets travelled over an old land surface and syntectonic molasse contemporaneously offlaps the topographic high of the thrust front this phenomenon occurs along the alpine thrust front in haute provence 4 the frontal fold represents deformation above a large scale thrust tip no unequivocal example of tip line strain at this scale has been recorded although this type of deformation may occur in the brooks range of alaska in many areas mountain fronts show a combination of these idealized geometries

examining spectral variations in localized lunar dark mantle deposits the localized lunar dark mantle deposits dmds in alphonsus j herschel and oppenheimer craters were analyzed using visible near infrared spectroscopy data from the moon mineralogy mapper spectra of these localized dmds were analyzed for compositional and mineralogical variations within the deposits and were compared with nearby mare basalt units spectra of the three localized dmds exhibited mafic absorption features indicating iron rich compositions although the dmds were spectrally distinct from nearby mare basalts all of the dmds contained spectral signatures of glassy materials suggesting the presence of volcanic glass in varying concentrations across the individual deposits in addition the albedo and spectral signatures were variable within the alphonsus and oppenheimer crater dmds suggesting variable deposit thickness and or variations in the amount of mixing with the local substrate two previously unidentified localized dmds were discovered to the northeast of oppenheimer crater the identification of high concentrations of volcanic glass in multiple localized dmds in different locations suggests that the distribution of volcanic glass across the lunar surface is much more widespread than has been previously documented the presence of volcanic glass implies an explosive vulcanian eruption style for localized dmds as this allows volcanic glass to rapidly quench inhibiting crystallization compared to the larger hawaiian style eruptions typical of regional dmd emplacement where black beads indicate a higher degree of crystallization improved understanding of the local and global distributions of volcanic glass in lunar dmds will further constrain lunar degassing and compositional evolution throughout lunar volcanic history

volumetric budget and grain size fractionation of a geological sediment routing system eocene escanilla formation south central pyrenees the supply of sediment and its characteristic grain size mix are key controls on depositional facies and stratigraphic architectures in sedimentary basins consequently constraints on sediment caliber budgets and fl uxes are a prerequisite for effective stratigraphic prediction here we investigate a mid to late eocene 41 6 33 9 ma sediment routing system in the spanish pyrenees we derive a full volumetric sediment budget weighted for grain size fractions partitioned between terrestrial and marine depositional sectors and we quantify sediment fl uxes between depocenters the paleo sediment routing system was controlled by syndepositional thrust tectonics and consisted of two major feeder systems eroding the high pyre nees that supplied a river system draining parallel to the regional tectonic strike and that ultimately exported sediment to coastal shallow marine and deep marine depo centers we show signifi cant changes in both the volume and grain size distribution of sediment eroded from the pyrenean mountain belt during three different time intervals in the mid to late eocene which controlled the characteristics of stratigraphy preserved in a series of wedge top basins the time averaged sediment discharge from source areas increased from 250 km 3 m y to 700 km 3 m y over the 7 7 m y interval investigated this temporal increase in sediment supply caused major westward progradation of facies belts and led to substantial sediment bypass through the terrestrial routing system to the initially marine jaca basin the grain size mix measured as size fractions of gravel sand and fi ner than sand also changed over the three time intervals integration of volumetric and grain size information from source to sink provides an estimate of the long term grain size distribution of the sediment supply comprising 9 gravel 24 sand and 67 fi ner than sand the techniques and concepts used in the escanilla study can profi tably be applied to paleo sediment routing systems in other tectonic and climatic settings and to catchments with a range of bedrock lithology and vegetation this will promote a better generic understanding of the dynamics of source tosink systems and provide a powerful tool for forward stratigraphic modeling the sediment routing system approach has the potential to contribute strongly to new models of sequence stratigraphy

flexural unfolding of horizons using paleomagnetic vectors this paper introduces a new restoration method pmag3drest designed for complex folded structures non cylindrical non coaxial it combines paleomagnetic vectors and bedding markers setting up a reference system that allows deformed and undeformed surfaces to be related to one another we assume flexural conditions during the deformation consequently the stratigraphic horizons are considered to be globally developable surfaces with total area preservation except in specific deformation areas using paleomagnetism in the proposed restoration process pmag3drest helps to locate these areas with greater accuracy it is similar to other approaches based on triangulations but it forces the available paleomagnetic data to converge with the paleomagnetic reference vector during the restoration process our experiments use computer and analog models in which the deformed and undeformed surfaces are perfectly known this enables us to apply the restoration method to the deformed surface and compare the parameters of the restored surface with those of the initial undeformed surface to quantify the quality of the method paleomagnetic data anchor the surface leading to more accurate results

coal deposition in carbonate rich shallow lacustrine systems the calaf and mequinenza sequences oligocene eastern ebro basin ne spain two main coal bearing sequences developed during the oligocene in the tertiary ebro basin the calaf early oligocene and mequinenza late oligocene coal basins coal deposition took place in shallow marsh swamp lake complexes which sometimes became closed and evolved under warm climatic conditions with fluctuating humidity these shallow lacustrine systems are closely interrelated with the terminal parts of the distributive fluvial systems which spread from the tectonically active ebro basin margins laterally extensive lignite bearing sequences including rather thin lenticular autochthonous and or hypautochthonous coal seams with high ash and sulphur contents characterized coal deposition in the shallow lacustrine systems coal seam geometry which makes them nearly subeconomic resulted from the tectonic instability during basin margin evolution and the sometimes closed arid conditions under which the lacustrine systems evolved high ash and sulphur contents resulted from the inadequate isolation of peat forming environments from clastic influx and from the very low acidity and sometimes high sulphate contents of the lacustrine waters coal exploration in shallow lacustrine sequences similar to those described here must take into account that the spread of coal forming environments and maxima of coal deposition are usually coincident with lake expansions and retraction or shifting of the terminal fluvial zones interrelated with the lacustrine areas

detection of temperature dependent spectral variation on the asteroid eros and new evidence for the presence of an olivine rich silicate assemblage data obtained by the near infrared spectrometer carried by the near shoemaker spacecraft show that the spectral properties of the asteroid eros vary with temperature the manner in which they vary demonstrates that the mineral olivine is a major constituent of the surface the near ir temperature dependent spectral properties of eros in the northern hemisphere and for two individual regions on the surface show clear evidence of the presence of the mineral olivine and are a close match to the temperature spectral behavior of ll type ordinary chondrite meteorites while the presence of other olivine rich meteorites cannot be excluded h type ordinary chondrites are clearly too pyroxene rich to be permitted as a major surface component of eros the results of the thermal spectral analysis are consistent with results from analysis of conventional reflectance spectra of the asteroid and contribute unambiguous detection of olivine to the understanding of the surface composition of eros

a review of recent research in fluvial sedimentology this volume has been compiled to represent the current status of research into fluvial sedimentology as part of the proceedings for the 5th international conference on fluvial sedimentology 5icfs brisbane july 1993 the volume contains papers on a wide variety of topics representing the diversity of interests covered by the icfs this review serves to introduce these papers within the context of recent research post1988 in fluvial sedimentology icfs papers may be somewhat arbitrarily divided into those which report fundamental studies of sediment transport studies of modern alluvial and coastal systems studies of environmental management of fluvial systems facies analyses of ancient fluvial sequences studies of controls on alluvial stratigraphy and basin fill and applied sedimentological studies of fluvialhosted mineral resources it is interesting to compare the balance of papers in this volume with that of previous icfs volumes miall 1978 collinson and lewin 1983 ethridge et al 1987 marzo and puigdefabregas 1993 as a guide to changing emphasis in fluvial sedimentology figure 1 illustrates the distribution of papers over the five icfs meetings categorised as above among various trends two are worthy of comment the first being the marked peak in interest in controls on fluvial sequence and basin fill at the 4icfs and the second the influx of papers on environmental management in this volume although there has been a steady level of activity in fundamental aspects of sediment transport and bedform generation the rela

the lunar opposition surge observations by clementine abstract the clementine mission to the moon in 1994 provided the first multispectral observations of the lunar opposition surge below a few degrees the brightness of the moon increases more than 40 between solar phase angles of 4 and 0 the opposition effect exhibits a small wavelength dependence the surge is 3 4 larger at 0 41 m than at 1 00 m this result suggests that the principal cause of the lunar opposition surge is shadow hiding while coherent backscatter if present makes only a minor contribution the amplitude of the effect depends significantly on terrain the surge is about 10 greater in the lunar highlands this difference is attributed to textural variations between the two terrains the clementine measurements provide a new basis for deriving spectral geometric albedos phase integrals and bond albedos a value of 0 11 0 01 was found for the lunar bolometric bond albedo this value is at the low end of the historical published values but not as low as the recent result of 0 080 0 002

stress pattern and strain release in the alpine foreland abstract illies j h baumann h and hoffers b 1981 stress pattern and strain release in the alpine foreland in p vyskocil r green and h malzer editors recent crustal movements 1979 tectonophysics 71 157 172 the tectonism of central europe is governed by a generally se nw 140 directed compressive stress flux from the alps towards their northern foreland since alpine folding had relaxed in the late miocene to early pliocene times only to be replaced by high rates of post orogenic uplift these stresses are understood to be of mainly topographic origin the strain release in the foreland is predominantly restricted to pre existing block boundaries shear or extensional movements could come about along those boundaries under the active regional stress regime the rhinegraben which was an extensional rift valley during the eocene to lower miocene has been subjected to a sinistral strike slip motion with shear controlled en echelon faulting on the present surface hydrothermal convection is observed along deep seated fissure systems held open by continuous shear strain since the central segment of the rift caused by its deviatory trend is under compressive shear strike slip motion will be slowed down in the near geological future a parallel shear belt about 100 km e of the rhinegraben became active by changing its function of primary normal faulting this belt characterized locally by high rates of pleistocene movements and some dense clusters of seismic epicenters swings around the impediment to shear which is situated in the central segment of the rhinegraben the shear motion of both belts converging towards the northernmost segment of the rhinegraben is blocked by the rhenish shield which interrupts the extension of the rift system transversally from here on a belt of seismic activity and slight pleistocene normal faulting traverses the shield in the northwesterly direction of maximum horizontal compression crustal rifting is lacking at this segment due to the tectonic incompetency of the prevailing slaty rocks of the hercynian basement to the north of this lithological unit the seismic belt extends to the rift segment of the lower rhine embayment which shows active crustal spreading along discrete dip slip faults

switches in subduction direction and the lateral termination of mountain belts pyrenees cantabrian transition spain the switch in subduction polarity at the transition from the pyrenees to the cantabrians implies an abrupt change in the gross direction of plate movement the pyrenees formed in response to the northward subduction of continental crust beneath europe during the palaeogene whereas the cantabrians developed during the southward subduction of biscay oceanic crust beneath spain as yet no attempt has been made to explain the mechanism and geometry of this apparent switch in plate kinematics the transition from northward to southward subduction occurs across a discrete lineament the pamplona fault oriented transversely with respect to the long axis of the adjacent mountain belts regional mapping reveals a 180 switch in the facing direction of thrusts and associated folds across the pamplona fault balanced structural cross sections constructed either side of the pamplona fault exhibit marked contrasts in bulk shortening depth to detachment gross structural geometry and the thickness and completeness of the pre orogenic mesozoic succession the pyrenean cantabrian transition zone is thus envisioned as a fundamental crustal lineament of pre orogenic origin a new model for the cenozoic tectonic evolution of north spain has the pamplona fault separating a series of transtensional basins in the pyrenees from a passive margin in the cantabrians subsequent plate collision between spain and europe reactivated the faults that controlled pre orogenic 9syn rift9 sedimentation in the present pyrenean area in the cantabrians however plate collision signalled a shift from a passive margin to an active margin consuming biscay oceanic crust beneath a northern spain subduction zone an implication of this model is that the foreland crust was affected variably by 9backarc9 heating during the early stages of spain europe collision this is expressed by the changing depth of the ebro basin the foreland basin that developed in response to pyrenean cantabrian orogenesis whose thickness of the tertiary succession varies laterally according to changes in flexural rigidity

impact induced thermal effects in the lunar and mercurian regoliths while the moon and mercury are similar objects in a geomorphologic sense they also possess important differences particularly in the context of small scale impact phenomena not only is the surface of mercury notably hotter than that of the moon but the impact flux is also more intense at mercury due to higher impact velocities and a greater spatial density of micrometeoroids by extrapolating the terrestrial micrometeoroid flux to the moon and mercury it is found that the impact rate at mercury is 5 5 times greater and the mean impact velocity more than 60 percent higher than at the moon a model of impact melting and vaporization applied to the lunar and mercurian environments indicates that almost 14 times more impact melt and over 20 times more vapor are generated per unit time in the mercurian regolith although the surface temperature plays a role in determining the melt and vapor volumes the difference in impact velocity appears to be markedly more important average craters formed by identical projectiles under the two velocity distributions on the two planets should be very similar in size because differences in the kinetic energy of the average impactors will be offset by the differences in gravitational acceleration as a result variations in regolith mixing should depend more on the actual impact rates than on disparities in excavated volumes each average impact on mercury however will produce more than twice as much impact melt as its lunar counterpart introducing more glass into the mercurian regolith although substantial quantities of impact vapor are produced on both planets mixing of the regolith should occur quickly enough in each case to spread the deposited vapor over large surface areas the resulting vapor coatings should be negligibly small for most purposes a much larger agglutinate population should exist on mercury and individual agglutinates should be similar to those of the lunar highlands reflectance spectra and visual albedos indicate that the mercurian crust possesses relatively small quantities of fe perhaps similar to those of apollo 16 light and dark matrix breccias laboratory studies have demonstrated that as the magnetic fractions which are correlated with agglutinate abundances of soils derived from these breccias increase the differences in 0 565 mm visible light reflectivity between the soils diminish should the regional variations in fe content of the mercurian crust be similar to those of these apollo 16 samples then the intense agglutination environment could account for the lack of optical contrast across the mercurian surface at the same time the very large fraction of impact glass in the regolith would imply that most pyroxenes have been fused and incorporated into these glasses seriously attenuating the fe2 crystal field absorption near 0 9 mm supporting this picture are the most recently published spectral observations of mercury which provide little or no evidence of such an absorption feature

effects of temperature on remotely sensed mineral absorption features laboratory spectral reflectance of mafic silicates has been measured over a temperature range characteristic of solar system objects to study the variation of diagnostic mineral absorption bands this information has become increasingly important with recent improvements in the quality of remotely sensed planetary data and the concurrent increase in sophistication of quantitative and qualitative spectrum analysis techniques in this study visible and near ir reflectance spectra 0 4 2 5 m of pyroxenes and olivine were obtained over a sample temperature range of 80 448 k these are the first published reflectance data for these minerals at temperatures significantly below ambient 300 k additionally thermal radiation emitted from the samples at elevated temperatures was effectively removed disclosing for the first time the high temperature reflectance behavior of pyroxenes in the diagnostic 2 m spectral region as expected from basic physical considerations fe2 crystal field absorptions in all samples become narrower with decreasing temperature the three components of the composite olivine band centered near 1 m become better resolved with decreased temperature and show changes in relative absorption strength there is not however any significant wavelength shift of the olivine reflectance minimum both orthopyroxene and clinopyroxene spectra show dramatic changes in band symmetry with temperature with the greatest change in the longer wavelength edge despite these significant changes in shape little if any change is observed in the wavelength position of reflectance minima of pyroxene absorptions near 1 m the 2 m pyroxene absorptions in contrast demonstrate major shifts of reflectance minima but in different directions in orthopyroxene spectra the band shifts to longer wavelengths with increased temperature while for the clinopyroxene spectra the band shifts to shorter wavelengths this behavior results in greatly improved spectral differentiation of orthopyroxene and clinopyroxene components in a mixture such as a basalt at reduced temperatures application of the results presented here to remote sensing mineral characterization techniques currently in use for determination of pyroxene composition can provide a moderate improvement to quantitative interpretations from 5 to 20 wt feo for orthopyroxenes and 5 wt cao for clinopyroxenes depending on planetary surface temperature

disk resolved photometric analysis of european terrains abstract using hapke s photometric model we examined the photometric textures of a representative subset of the geologic units on europa defined by lucchitta and soderblom 1982 satellites of jupiter pp 521 555 university of arizona press tucson the individual units studied possess the same small mean photometric slope angle as that found by domingue et al 1991 icarus 90 30 42 for the entire disk with one major exception the particles composing the surfaces of most of the units have similar scattering properties however the single particle scattering functions of the two bright plains regions examined are very different from each other and from the other units if the bright plains units are geologically younger than the other units an aging process that affects the single particle phase functions and albedos is inferred in our previous study we concluded that the disk integrated photometric properties of europa could not be explained adequately by ion bombardment however a new study on the effects of ion irradiation on the optical properties of materials sack et al 1991 j geophys res e 96 2 17535 17539 renders this conclusion invalid

regional stress field and rifting in western europe abstract baumann h 1981 regional stress field and rifting in western europe in j h illies editor mechanism of graben formation tectonophysics 73 105 111 in situ stress determination is one possibility to determine stress magnitudes in the earth s crust most measurements especially in the northern alpine foreland have been carried out by using the doorstopper technique stress magnitudes are presented as excess stresses a number of sites where stresses have been determined gave sufficiently high values to statistically determine stress directions for the following tectonic blocks 1 western alps 2 their immediate foreland with the rhinegraben and 3 the rhenish shield bordering on the rift segment of the lower rhine embayment in discussing results of the statistical analyses of stress data it is suggested that stresses measured in the western alps have mainly a topographic origin in the alpine foreland to the north of the rhenish shield topographic stresses are superimposed on active tectonic stress considering the structural and lithological differences the foreland blocks show a different response to the same tectonic stress field which trends for 1 at about 146 this active stress field causes shear rifting in the upper rhinegraben but extensional rifting in the lower rhine embayment in the rhenish shield area only local step faults are observed in direction of 1 due to the ductile behaviour of its basement

discussion on palaeostresses associated with thrust sheet emplacement and related folding in the southern central pyrenees huesca spain journal vol 152 1995 353 356 journal vol 152 1995 353 356 j p turner p l hancock write we congratulate martinez pena casas sainz and millan garrido 1995 on their palaeostress analysis of a complex suite of mesostructures contained in several south pyrenean thrust sheets we agree that in spite of the difficulty in interpreting the multi phase deformation of thrust belts analysis of structures from which palaeostress may be inferred yields useful information not apparent from a macro structural study like martinez pena et al 1995 we also found that the folded oligo miocene molassic sedimentary rocks of the jaca thrust top basin contain remarkably few faults indeed explaining how a near surface structural unit has travelled 30 km or more over such an irregular tectonic topography yet without being faulted is a challenging structural question however we are suprised that martinez pena et al 1995 found in their palaeostress results from the cretaceous and palaeocene carbonates to the north of the molasse basin that there are no great differences between stress tensors found in the hanging wall and the footwall of thrusts our experience turner hancock 1989 in that part of the jaca basin contiguous with and immediately to the west of their study area is that the assemblages of small scale brittle structures in the immediate within 1 3 km hanging walls and footwalls of thrusts are distinctively different recording locally contrasting stress regimes in particular our study showed that the immediate footwalls of thrusts experienced extension parallel to the strike of thrusts before they underwent extension normal to the strike of thrusts

a classification of thrust fronts variations in structural style at thrust fronts are examined to determine whether they represent different stages of typical thrust sheet development or unique events as orogenic stresses declined thrust fronts are classified as buried or emergent in which either the sole thrust died out in the subsurface or emerged to the synorogenic surface buried thrust fronts are subdivided into two types type 1 fronts end in broad zones of low strain type 2 fronts end in zones of high strain emergent thrust fronts may display significant horizontal displacement strongly emergent or limited displacements of about 1 km weakly emergent tip stick thrust fronts exhibit high strains and out of sequence thrusting different types of thrust fronts are linked by transitional tip li e anticlines and strike slip zones most thrust front types represent different stages of typical thrust sheet development but those in type 1 display atypical development unique to thrust fronts

a seismic refraction study of the western tuz golu basin central turkey summary in 1970 the turkish petroleum company carried out a seismic refraction experiment in the tuz golu salt lake basin of central turkey we present our interpretation using time term analysis and ray tracing of data from one of the two lines shot this confirms the presence of a thick sequence of sedimentary layers varying from about 3 km below the southwestern end of the profile to about 10 km at two points along the line a p wave velocity of 4 0 4 2 km s 1 found beneath the low velocity surface layer indicates that the principal sedimentary layer consists of evaporites the lowermost layer of the model has a p wave velocity of 6 15 km s 1 which is consistent with the sedimentary layers being underlain either by cretaceous metamorphic basement or by lavas of andesitic type the extensive coverage provided by this data set has enabled the construction of a detailed 2 d model which shows the complex topography of the subsurface layers we identify two major faults and one minor fault affecting both the basement and overlying layers the character of these features and the associated layer displacements leads us to speculate that these may be growth faults associated with the aksaray ereflikochisar and karapinar cihanbeyli haymana hinge structures which have controlled the development of the tuz golu basin