tectonic significance of mafic volcanic rocks in a mesozoic sequence of the menderes massif west turkey the mesozoic platform sequence of the menderes massif consists of thick succession of detrital and carbonate rocks in this sequence there are mafic metavolcanic rocks at two different levels the first level of mafic metavolcanic intercalations is in the late triassic detrital rich series located in the caltasi formation which is the lowermost unit of the mesozoic platform the second level of the mafic metavolcanic rocks is located in the late cretaceous paleocene selcuk formation laying on top of the platform sequence the caltasi formation which is composed of mica schists thinly bedded cherts calc schist and mafic volcanic intercalations unconformably overlie the bayindir formation which consists of mica schists phyllites and white quartzites of palaeozoic or probably older age the mafic volcanic rocks in the caltasi formation are alkaline basalts with within plate characteristics and are formed during an intraplate extension the caltasi formation is conformably overlain by the kayaalti formation represented by calc schists dolomitic marbles and rudist and emery bearing massive marbles in ascending order the selcuk formation overlies the kayaalti formation and consists of a mica schist matrix with allochthonous blocks of mafic volcanic rocks metaperidotites metagabbros and massive marbles the mafic volcanic rocks in the selcuk formation are tholeiitic basalts and are petrologically similar to mid oceanic basalts the geological and geochemical characteristics of the mafic metavolcanic rocks in the caltasi formation indicate that during the late triassic the menderes platform was segmented probably by the opening of a branch of the neotethyan ocean between the late triassic and the late cretaceous the menderes carbonate platform was built up during the latest cretaceous early paleocene a slab of oceanic crust obducted on this platform and provided slices of mafic metavolcanic rocks into the selcuk formation

laboratory study of hydraulic fracturing laboratory tests on teton dam soil were performed by increasing the water pressure in model bore holes and in simulated rock joints the water pressure required to cause hydraulic fracturing was found to depend on soil density water content confining stress and test duration on the basis of the test results it was hypothesized that 1 hydraulic fracturing is a weak link phenomenon in that fracturing will occur in the least resistant soil subjected to increased water pressure and 2 hydraulic fracturing can probably occur only in the presence of a discontinuity within which the water pressure can act to create a wedging mechanism thus creating tensile stresses in the soil

interaction mechanism between deep mixing column and surrounding clay during installation laboratory and field investigation has shown that the shear strength of the surrounding clay increased in the vicinity of a deep mixed dm column in the short period following installation field observations indicated that significant excess pore pressure which may be higher than the hydraulic fracture pressure was generated during installation the behaviour between a dm column interacting with the surrounding clay during installation can be simulated as the shearing expanding process of a cylindrical cavity a simple approach is proposed to calculate the excess pore pressure around a dm column during installation the proposed method of calculation considers the effect of a shearing force caused by rotating blades during mixing in the proposed approach the excess pore pressure is expressed in terms of undrained strength of clay shearing force injection pressure and a pore pressure parameter an approach is developed to analyze clay fracturing using a tensile failure mechanism analytical results

alpine high p low t metamorphism of the afyon zone and implications for the metamorphic evolution of western anatolia turkey abstract carpholite chloritoid pyrophyllite association occurs widely in the triassic metaclastic rocks of the afyon zone in west central turkey fe mg carpholite is associated with rare aragonite pseudomorphs and glaucophane in marbles and metabasites respectively the afyon zone consists stratigraphically of a pan african basement and an overlying mesozoic cover sequence the pan african basement which shows barrovian type amphibolite facies metamorphism comprises garnet mica schists intruded by sodic amphibole bearing metagabbros and leucocratic metagranites it is unconformably overlain by a continuous metasedimentary sequence extending from triassic to early palaeocene this cover sequence begins with metaconglomerates which pass upwards into phyllites fe mg carpholite occurs within this metaclastic sequence as rosette like crystals in metapelites and fibres in quartz segregations the metaclastic rocks are succeeded by metamorphosed platform carbonates grading into latest mesozoic metamorphosed pelagic limestones which in turn progress up to a late mesozoic early tertiary olistostrome this sequence is tectonically overlain by the blueschists of the tavsanli zone fe mg carpholite bearing assemblages imply temperatures of about 350 c and minimum pressures of 6 9 kbar corresponding to burial depths of about 30 km for the mesozoic passive continental margin sediments and the underlying pan african supracrustal metasediments and metaintrusives the metamorphic rocks of the afyon zone are unconformably overlain by upper palaeocene lower eocene sedimentary rocks indicating a paleocene age for the regional hp lt metamorphism this implies continuous younging of hp lt metamorphism in the anatolides related to northward subduction of the anatolide tauride platform beneath the sakarya zone from north to south this involved the tavsanli zone campanian 80 5 ma the afyon zone palaeocene the menderes massif middle eocene and the lycian nappes late cretaceous eocene all of which were probably derived from the frontal part of the anatolide tauride platform

physical weathering of marbles caused by anisotropic thermal expansion marbles as building stones as well as in their natural environments show complex weathering phenomena the most important damage scenario is based on the highly anisotropic thermal expansion coefficient of calcite i e extreme expansion parallel and contraction normal to the crystallographic c axis therefore the rock fabric and especially the lattice preferred orientation texture of calcite and or dolomite as the predominant mineral phases in marbles have a significant influence on the mechanical weathering the textures of marbles from five different locations vary from a more or less perfect prolate to moderate oblate shape of the 006 pole figure tensor accordingly the texture derived bulk thermal dilatation anisotropy covers a broad range from 0 048 to 0 680 the modelled thermal dilatations correlate with those obtained from experimental measurements the difference in magnitude is basically explained by the microcrack fabrics which was not considered in the computations all samples show a deterioration due to thermal treatment regardless of the strength of texture the directional dependence of a the total magnitude of the thermal dilatation coefficient and b of the residual strain is highest in marbles with a strong texture whereas the carrara marble with a weak texture exhibits a uniform crack formation the progressive loss of cohesion along grain boundaries due to dilatancy may serve as an example for the initial stage of physical weathering

forensic numerical analysis of gas venting in southwestern ontario abstract a forensic modeling study examines the potential causes of gas and water venting observed during the excavation of a landfill in a 40 m thick clayey till deposit in southwestern ontario canada the clayey till is known to be underlain by permeable natural gas bearing rock and gas has been diffusing through the clayey deposit over about the last 13 000 15 000 years attention is focused on 2d modeling of hydrofracturing as well as gassy soil behavior the model examines the predicted location of venting with and without the presence of gassy sand lenses and a discontinuous layer of basal till between the bedrock and the low permeability till the modeling shows that hydrofracturing alone can explain the occurrence and location of the observed venting in one of the sub cells in the other sub cell hydrofracturing explains the occurrence but not the location of the observed venting or the presence of the sand in the venting water at this location modeling of appropriately placed gassy sand lenses is shown to explain the occurrence and location of the observed venting as well as the presence of both waters with different geochemistry from the bedrock and the till in the venting waters

thermal and salt crystallization effects on marble deterioration examples from western anatolia turkey six commercially available and extensively used turkish marbles having different textural properties were subjected to ageing tests in order to assess their resistance against salt crystallization with thermal effect the change in physico mechanical properties of the marbles including weight dry unit weight effective porosity water absorption dry and saturated sonic velocities uniaxial compressive strength ucs indirect brazilian tensile strength flexural strength abrasion value and impact resistance has been determined for various stages of the ageing tests the results are evaluated in terms of the grain size grain boundary and grain size distribution of the marbles based on the test results the physico mechanical properties of the marbles are not uniformly affected from the ageing tests the water absorption effective porosity ucs sonic velocity and abrasion value of the marbles are found to be good parameters to assess the deterioration and quality of the marbles whereas the weight loss unit weight brazilian tensile strength and impact resistance of the marbles are not the marbles having small grain size dominant grain size distribution in a narrow range and irregular grain boundary are more resistant against the ageing tests than the ones with large grain size grain size distribution in a wide range and straight grain boundary

strain investigations on calcite marbles using neutron time of flight diffraction in order to describe and explain the effect of bowing of marble facade panels neutron time of flight diffraction was applied to determine residual macro and microstrain on the calcite mineral phase the measurements were combined with investigations of the crystallographic preferred orientation texture measurements by neutron diffraction macroscopic measuring of the bowing on marble building stones as well as microfabric analyses three samples were investigated to explain the bowing effect a fresh broken sample a good conditioned facade panel and a strongly deformed facade panel residual intracrystalline strain was detected in all investigated samples which differed in the degree of bowing for the first time the preferred orientation and the residual strain were found to be related the results show that different strain magnitudes are reflected by residual strains which differ significantly in magnitude and direction furthermore different bragg peak widths have been detected as an indication of microscopic strain the observed residual strain values in the samples are related with the grain shape and texture properties

insolation weathering and hygric dilatation two competitive factors in stone degradation in the natural environment temperature and moisture are very important parameters in stone degradation therefore on 28 samples from different lithologies magmatic metamorphic and sedimentary rocks thermal and hygric expansion measurements were performed in order to constrain their behaviour related to environmental changes it was shown that marbles even those that are dolomitic are sensitive to temperature impacts for rocks with clay minerals the effect of temperature may be responsible for shrinking finally the amount of residual strain i e the formation of microcracks due to temperature action controls the rate of stone degradation for most sedimentary rocks no residual strain after heating was observed in contrast to most magmatic and metamorphic low porosity rocks sedimentary rocks contain swelling minerals like smectite and even phyllosilicates which are very sensitive to hygric attacks the cycles of wetting and drying i e the natural environmental effects may significantly control the deterioration velocity caused by hygric expansion

durability of carbonate rock as building stone with comments on its preservation carbonate rocks have been extensively used as building stones because of their availability workability and attractiveness unfortunately however some stones suffer from chemical attack or freeze thaw activity the environmental affects especially those due to pollution of the atmosphere are discussed in terms of weathering processes salt crystallization and acid deposition a review of some recent research in relation to deterioration of stone in urban environments is given and carbonate rocks are classified in relation to position within a building geographical location and degree of pollution some comments on stone preservation are provided especially in terms of the properties a preservative should possess

observations of hydraulic fracturing in soils through field testing and numerical simulations hydraulic fracturing is a potential cause of leakage of earth dams or loss of fluid in drilling and field permeability testing the effect of hydraulic fracturing on soil grouting is also a major c

astronomical dating of a tectonic rotation on sicily and consequences for the timing and extent of a middle pliocene deformation phase a detailed palaeomagnetic study of long and continuous middle pliocene sections from the caltanisetta basin on sicily reveals a differential clockwise rotation occurring around 3 21 ma the rotation appears to be a rapid event 80 000 100 000 years which suggests that the responsible tectonic processes also occur rapidly its timing corresponds closely to the transition from the trubi to the narbone formation at 3 19 ma this transition marks a major change in sedimentary environment on sicily and in calabria and it is coeval for instance with the onset of sapropel formation in the eastern mediterranean apparently it marks a synchronous and central eastern mediterranean wide event data from the oldest sediments overlying the tyrrhenian basement odp leg 107 suggest an acceleration in opening of the tyrrhenian sea during the middle pliocene we speculate that this acceleration is related to a transpressional event in the sicilian fold and thrust belt and extension which formed troughs in the foreland the strait of sicily thrust imbrication accompanying the transpressional event on sicily induced the middle pliocene clockwise rotation and resulted in shallowing of the caltanisetta basin causing the change in sedimentation regime characterised by the trubi narbone transition following this middle pliocene tectonic phase no rotation took place in the southern apennines calabria and sicily until the middle pleistocene 1 0 0 7 ma 1998 elsevier science b v all rights reserved

fracturing pressure in clay abstracthydraulic fracturing in clayey soils can be triggered by either tensile or shear failure in this paper the physical meanings of various equations to predict fracture initiation pressure proposed in the past are discussed using the cavity expansion theory in particular when fracturing pressure is plotted against initial confining pressure published laboratory test results as well as analytical models show a linear relationship when the slope is close to 2 fracture is initiated by tensile failure of the clay whereas when the slope is close to 1 it is initiated by shear failure of the clay in this study the analytical models validated only on laboratory test data to date were applied to unique data from field grouting work in which extensive soil fracturing was carried out to improve the mechanical characteristics of the soft silty clay underlying a bell tower in venice italy by a careful assessment of initial confining pressure in the field the variation in recorded injection pressur

impact of salt and frost weathering on the physical and durability properties of travertines and carbonate tufas used as building material this study was financed by the spanish ministry of education and science mec through the research project cgl2006 05027 bte and community of madrid s2023 mit 2914 a pre doctoral research fellowship was awarded to n cueto by the mec

effects of abutment slopes on the performance of high rockfill dams une methode par elements finis tridimensionnelle non lineaire a ete utilisee pour analyser le comportement general contrainte deformation de barrages en enrochements de grande hauteur dans des vallees etroites l influence de la pente des appuis sur l effet de voute qui prend place dans le sol des barrages est largement discutee de meme que le potentiel de fracturation hydraulique dans le noyau et la fissuration dans les zones de contact du noyau on a aussi analyse et compare le comportement de barrages de differentes hauteurs on suggere des ameliorations pour la preparation des fondations des noyaux et pour la protection vis a vis de la fissuration

fluid driven fractures in uncemented sediments underlying particle level processes article i nfo granular materials subjected to fluid flow may experience fracture formation and fluid flow localization current explanations for hydraulic fracture in soils fail to satisfy the inherent characteristics of granular materials effective stress dependent cohesionless frictional strength we apply complementary experi mental and numerical techniques to identify the underlying particle scale mechanisms first we show that the miscibility of the invading fluid with the host fluid leads to distinct localization processes that depend on the balance between particle level skeletal forces effective stress dependent capillary forces the invasion of the interfacial membrane when immiscible fluids are involved and seepage drag forces associated with fluid flow velocity then we identify the positive feedback mechanisms at surface defects and fracture tips that promote fracture initiation and sustain fracture propagation these include increased porosity at the tip due to strains preferentially normal to the fracture alignment either eased membrane invasion immiscible fluids or higher hydraulic conductivity miscible fluids and the emergence of particle level forces that promote opening mode particle displacement this effective stress compatible sequence of events helps identify the parameters that govern fluid driven fracture formation in uncemented sediments and explain experimental observations