oligocene shallow water lacustrine deltas of the baxian sag of bohai bay basin eastern china depositional response during rift to thermal tectonic subsidence transition using cores well logs and other borehole data the results of this study show that the shallow water lacustrine delta has its own unique depositional characteristics of the third member of oligocene dongying formation ed3 in the baxian sag bohai bay basin eastern china during the ed3 stage the rift thermal basin subsidence transition stage the paleoslope was divided into multilevel slopes by faults along the wen an slope with slope angles from approximately 0 19 to 2 02 the paleogeographic conditions low discharge channel and low accommodation controlled the sedimentary characteristics the distributions of the shallow water delta system were controlled by multilevel flexure slopes the delta plain was distributed on the first and second level slope belts and the delta front was distributed on the third level slope belt the high sinuosity fluvial channel of the delta plain was the dominant facies in the whole shallow water delta most sand was deposited in these channels along the second level slope belt therefore not enough sand was present to be transported into the lake shallow water to form mouth bars in the delta front therefore mouth bars of the shallow water delta front were few and the sand beds were thin additionally no more sand was available to be supplied right along to deep lake the lacustrine basin was small and there was insufficient accommodation and sand to develop a subaqueous fan in the delta front

dual porosity mechanism for transient groundwater and gas anomalies induced by external forcing abstract the geochemical response of groundwater to external forcing is studied in a tunnel hosted in fractured gneiss near and above an artificial lake having large water level variations dripping waters have been monitored in two zones characterized by highly different flow rates representing different contributions of water from matrix porosity and fractures transient increases of sulfate and magnesium concentrations observed in both zones are not related to meteorology but associated with radon bursts into the tunnel air this indicates that transient enhancement of conductance with discharges of saline water and radon from the matrix porosity to the fractures is a mechanism able to produce both groundwater and gas anomalies in response to hydrogeological or mechanical processes such as increases in pore pressure or changes in crack geometry besides its applications to environmental issues the proposed discharge mechanism may be relevant for the understanding of geochemical precursors of earthquakes as an alternative to aquifer mixing

a conceptual model for glaciogenic reservoirs from landsystems to reservoir architecture abstract glaciogenic sediments are present in many hydrocarbon producing basins across the globe but their complex nature makes it difficult to characterise the reservoir quality sedimentary units despite this ordovician glacial deposits in north africa and carboniferous permian glaciogenic sequences in the middle east have been proven to host significant economical hydrocarbon accumulations additionally discoveries have been made in the shallow

pore properties as indicators of breakdown mechanisms in experimentally weathered limestones the results are reported of four experimental weathering tests freeze thaw wetting and drying slake durability and salt weathering on five different types of limestone effective porosity mercury intrusion porosimetry and scanning electron microscopy were used to evaluate changes in pore properties while weight loss and fracture density were used to assess deterioration severity a primary aim was to observe modifications in porosity due to weathering and to draw inferences about the internal rock deterioration mechanisms taking place it is concluded that the five limestones not only show a wide range of resistance to weathering in general but considerable difference in resistance to particular weathering processes consequently when assessing durability it is essential to consider rock properties in the context of the weathering process to which the rock is subject the type of deterioration indicator used is also important in interpretation of durability a variety of pore modification mechanisms operate including changes in pore connectivity pore infilling and the introduction of additional void space there are indications that changes to the internal pore structure of rocks due to weathering may be a precursor to more substantial macrodeterioration copyright 2001 john wiley sons ltd

salt weathering in dual porosity building dolostones abstract the influence of rock fabric on physical weathering due to the salt crystallization of selected brecciated dolostones is discussed these dual porosity dolostones are representative of heterogeneous and anisotropic building rocks and present highly complex and heterogeneous rock fabric features the pore structure of the matrix and clasts is described in terms of porosity and pore size distribution whereas the relative strength for each textural component is assessed using the knoop hardness test the whole characterisation process was carried out using the same samples as those used in the standard salt durability test en 12370 including connected porosity the water saturation coefficient fissure density compressional wave velocity and waveform energy results show the most important rock fabric elements to be considered are the matrix and clast properties and the nature of fissures firstly a relatively weak matrix was the focus of major granular disintegration as it presents high porosity low pore radius and reduced strength secondly narrow micro fissures appear to be important in the decay process due to the effectiveness of crystallization pressure generated by salt growth on the contrary macro fissures do not contribute greatly to rock decay since they act as sinks to consume the high supersaturations caused by growth of large crystals additionally an analysis of stress generated by crystallization was carried out based on the general situation of a lenticular crystal geometry finally the relationships between whole petrophysical properties and durability were established using a principal component analysis this analysis has clearly established that the durability of rocks affected by salt crystallization mechanisms diminishes in weaker and anisotropic rocks with high porosity and fissure density

facies analysis of a pliocene river dominated deltaic succession siena basin italy implications for the formation and infilling of terminal distributary channels the recent recognition and description of terminal distributary channels in ancient delta front deposits have led to important progress when it comes to understanding delta construction processes the plan view shapes of both modern and ancient river dominated deltas and sediment dispersal within deltas deltaic deposits fed by terminal distributary channels can be observed in the extensive outcrops approximately up to 300 m wide and 50 to 70 m thick in the central sector of the pliocene siena basin in tuscany italy stratigraphic constraints indicate that the deposition occurred in relatively shallow marine settings was not affected by tidal effects and was influenced only locally by wave action as a consequence these rock exposures provide an opportunity to investigate the facies assemblage of an ancient delta complex which was built up almost exclusively as the result of river related processes the studied deltaic succession is composed of vertically stacked parasequence like units which are invariably characterized by the lack of coarse grained distributary channel deposits at the top and an extensive network of terminal distributary channels that controlled the deltaic deposition these deposits were interpreted previously as deep water turbidites this study provides new elements for the correct distinction between hyperpycnal dominated delta fronts and basinal turbidite deposits the terminal distributary channel facies documented in this study are more complex than those investigated in previous research the channels are often passively filled during abandonment phases and not just due to the aggradation and lateral upstream migration of mouth bars as classically proposed moreover the frequent occurrence of mudstone beds just above the basal channel scours may be indicative of an abandonment phase after the channel incision and before its infilling with subsequent implications for the formational and infilling mechanisms of terminal distributary channels furthermore the channel fills are often the result of alternating depositional and erosional phases leading to a complex stratigraphic arrangement

bayhead deltas and shorelines insights from modern and ancient examples abstract bayhead deltas are important components of the rock record as well as modern estuaries hosting important hydrocarbon reservoirs and many coastal cities ports and large expanses of wetlands despite their significance few studies have summarized their occurrence and sedimentary characteristics in this paper we review the stratigraphic sedimentary and geomorphic characteristics of 68 modern and ancient bayhead deltas bayhead deltas are found in incised valleys structural basins fjords interdistributary bays of larger open ocean deltas and other backbarrier environments except for within fjords they generally prograde into shallower and more brackish waters than their open ocean equivalents as a result 80 of modern 68 of quaternary and 67 of ancient bayhead deltas have clinoform thicknesses of 10 m or less with 73 of modern bayhead deltas having clinoform thicknesses of 5 m or less additionally 89 of modern 81 of quaternary and 77 of ancient bayhead deltas examined are fluvial dominated we distinguish true bayhead deltas from their genetically similar bayhead shorelines which are not constructional features but sites of enhanced marsh or estuarine sedimentation near river mouths with inadequate rates of sediment delivery to form distributary channels and prograde into the estuary or lagoon we also distinguish confined bayhead deltas found in incised valleys structural basins and fjords from unconfined bayhead deltas found as incipient lobes of larger delta complexes and other back barrier lagoons the architecture of confined bayhead deltas is largely influenced by the limited accommodation brought about by the walls of the flooded valleys in which they are located as such confined bayhead delta ontogeny is controlled by many autogenic interactions within these valley walls both confined and unconfined bayhead deltas are sensitive to sea level rise climate controlled changes in sediment flux and tectonics their relatively small size connection with the terrestrial system and protected nature make them the ideal depositional system to record earth history including sea level and climate changes

upscaling of small scale heterogeneities to flow units for reservoir modelling the effect of small scale heterogeneities on fluid flow through a reservoir is determined using one of so called mathematical upscaling methods that as such are fairly well established less well established however are the operations that provide their input i e construction of reservoir model and acquisition of data we thereto propose systematic description of facies and bed and systematic data sampling we upscale the ensuing model and data through a two step flow simulation i e first on the flow cell and then on the flow unit scale this work provides for a straightforward and easily applicable upscaling method that incorporates the effects of all heterogeneities

the genesis of dedolomites a discusion based on reactive transport modeling abstract dedolomites are rocks formed by the replacement of dolomite with calcite which is driven by the infiltration of ca rich water this process has been described in the literature as either increasing preserving or decreasing porosity of the initial dolostone according to textures observed in prades ne spain dedolomitization took place due to two simultaneous processes non pseudomorphic replacement of dolomite with calcite at the wall rock of fractures and pseudomorphic replacement in the bulk rock a multicomponent reactive transport model is used to analyze the two dedolomitization processes observed diffusion of ions from the fractures was the driving force for non pseudomorphic replacement in the wall rock the dissolution of dolomite and precipitation of calcite took place in accord with a 1 2 stoichiometry as a consequence of the mineral molar volume the porosity was sealed and replacement limited to a rim on both sides of the fractures according to calculations the development of a rim took less than 500 years advection of ions from the top of the dolomite bed was the driving force for pseudomorphic replacement in the bulk rock due to the absence of empty volume for expansion replacement was governed by the condition of equal volumetric rate for dolomite dissolution and calcite precipitation according to calculations pseudomorphic replacement of 1 m of dolostone was completed after about 10 5 years for reasonable values of flow parameters as the infiltrating water was also undersaturated with respect to calcite one stage of calcite dissolution postdated dedolomitization this process was responsible for the widening of open fractures where the dissolution front followed the dedolomitization front into the dolomite matrix intensive calcite dissolution was also developed following the advective flux from the top of the bed downwards drusy calcite is observed to precipitate in the pore spaces which consist of intergrains fractures and dissolution cavities this process is not predicted in detail by reactive transport calculations although it may be due to calcite supersaturation of the solution resulting from pseudomorphic dedolomitization

sampling procedure for small scale heterogeneities crossbedding for reservoir modelling sampling permeability from individual laminae in crossbedded rocks is very well possible by making use of a so called probe permeameter the methodology and calculation of permeabilities from the output of this instrument are fairly well established however what is hardly established is a sampling strategy that guarantees adequate representation of permeability contrast between laminae especially so because finer foreset and bottomset are difficult to sample yet their permeabilities are critical to fluid flow through a crossbed therefore we propose to systematically sample laminae to this end we suggest a sampling strategy that is adapted to the heterogeneity under study namely to the thickness of the finer foreset

deterioration mechanisms of tuffs in midas monument slightly weathered white and pink tuffs of the midas monument have deterioration problems in this study depths and characteristics of the weathering zones developed within the tuffs are investigated through optical microscopy x ray diffractometry xrd chemical analyses scanning electron microscopy sem and some index parameters accelerated weathering tests including wetting drying freezing thawing and salt crystallization are performed and durability assessment methods are used to predict the durabilities of the tuffs the findings are compared with field observations by examining quantitative weathering indices and comparing them with thin section studies it is found that thin section analyses of the crystals loi and wpi are good indicators to quantify the depth of weathering for the tuffs however thin section studies have limited value for fine grained tuffaceous matrix the chemical weathering of the tuffs produces weathered zones that are 4 5 cm thick within the white tuff and 2 5 cm thick within the pink tuff physical weathering causes scaling of outer layers of the tuffs and fracturing of feldspars along their cleavage planes however variations of the index properties of the tuffs due to weathering are not so significant to quantify the weathering depths in the tuffs among the accelerated weathering tests salt crystallization is found to be the most destructive environmental condition pigeon droppings rich in no3 are found to be the main source of soluble salt at the midas monument the salt transported up by capillary rise due to surface water causes spalling of the tuffs in the capillary zone surface water and salt of any kind in the close vicinity of the monument should be totally eliminated for the purpose of conservation field observations and the durability equations reveal that the white tuff is less durable than the pink tuff wet to dry strength ratio yields a better stone durability assessment among various durability methods used in this study d 2002 elsevier science b v all rights reserved

syn tectonic sedimentation in a neogene strike slip basin containing a stacked gilbert type delta se spain abstract the pliocene sedimentation in the cerro blanco ei barranquete subbasin cbb subbasin that forms part of the larger almeria nijar carboneras basin anc basin is controlled by a releasing overstep and a restraining zone in the ne trending serrata strike slip fault zone the sedimentary development of this subbasin can be considered in three stages of a fault kinematic model during stage i a wave influenced shoaling zone was present in front of an emergent serrata cape to the ne with a basin to the sw and w uplift of the shoaling zone in a restraining n080e trending cerro blanco fault zone cb fault zone is evidenced by the following syn tectonic sedimentary phenomena a a rotational unconformity towards the nw b four deepening pulses in the shallow water zone c massflow deposits originating from a near coastal zone possibly triggered by tectonic pulses during stage ii the uplifted zone became increasingly shallow and finally emerged quartz pebbles in the sediments that indicate a land connection between the serrata cape and the metamorphic basement in the north differentiate this stage from the previous one prograding shoreline deposits marked the outbuilding of the serrata cape towards the sw an episodically subsiding zone due to a releasing overstep between the sinistral n040e trending nw serrata boundary fault nwsb fault and b fault during stage ila is indicated by a southwestward outbuilding fandelta during this stage there was only one depocentre during stage ilb the depocentre of the subsiding zone split up this shifting of depocentres is explained according to the releasing overstep model by an increase of the overlap between the nwsb fault and the b fault during stage iii the cbb subbasin became continental and was inverted as demonstrated by its present day relief the area was severely faulted by n040e trending r and y shears on a metre scale which led to an estimated cumulative sinistral displacement of 2 km since fandelta deposition the present day activity of the nwsb fault is shown by sinistrally deflected stream courses and pressure ridges

a sand gravel gilbert delta subject to base level change laboratory experiments were conducted on a sand gravel gilbert delta to gain insight on its dynamics under varying base level base level rise results in intensified aggradation over the topset as well as a decrease in topset slope and topset surface coarsening the signals of which migrate in an upstream direction preferential deposition of coarse sediment in the topset results in a finer load at the topset foreset break which creates a fine signature in the foreset deposit base level fall has the opposite effects entrainment of the topset mobile armor causes a coarsening of the load at the topset foreset break and so a coarse signature in the foreset deposit the entrainment of the topset substrate and fine top part of the foreset may follow which causes a fining of the load and a fine signature in the foreset deposit the fact that the upstream sediment supply requires a certain slope and bed surface texture to be transported downstream under quasi equilibrium conditions counteracts the effects of base level change this information travels in the downstream direction in nature base level change is likely so slow that the upstream sediment load maintains the topset slope and bed surface texture and so keeps the topset in a quasi equilibrium state base level change is therefore not expected to leave a clear signal in a mixed sediment gilbert delta other than a change in elevation of the topset foreset interface

morphology and sedimentology of deltas in fjord and fjord valley lakes abstract sediment supply depositional processes and the associated morphology and sedimentology of deltas in a fjord and several fjord lakes have been studied two deltas in lakes in eastern norway receive sediments from fluvial erosion of quaternary glacial deposits and are only to a slight extent influenced by modern glaciers the other deltas are situated in western norway in the drainage area of the jostedalsbreen ice cap the meltwater rivers draining this glacier are characterized by a high rate of sediment transport in a wide range of grain sizes the main modes of the grain size distribution curves occur in the silt sand and cobble fractions the sediment transport and the water discharge of the rivers have been measured during the same periods the sedimentation rate of different grain fractions and their downstream variation in the frontal area of the deltas were determined by sediment traps the morphology of the deltas have been investigated with echo sounding differences in downstream sedimentation rates of the various deltas are related to dynamic and geometrical properties of the systems the effect of different factors on delta morphology and sedimentology is discussed

morphological expression of bedforms formed by supercritical sediment density flows on four fjord lake deltas of the south eastern canadian shield eastern canada high resolution swath bathymetry data collected in fjord lakes pentecote walker and pasteur eastern quebec canada allowed imaging in great detail the deltas of four rivers in order to understand the factors controlling the formation and downslope evolution of bedforms present on their slopes the morphometry and morphology of 199 bedforms reflect the behaviour of sediment density flows the shape of the bedforms mostly crescentic and the relationships between their morphological properties indicate that they were formed by supercritical density flows and that they are cyclic steps the crescentic shape suggests an upslope migration while the aspect ratios and increasing wavelengths with distance from the shore and decreasing slopes are compatible with a cyclic step origin at the rollover point the acceleration of the density flows on steep slopes produces tightly spaced hydraulic jumps and favours short wavelength and symmetrical bedforms further downslope decreasing slopes and increasing specific discharge increase the wavelength and asymmetry of the bedforms the wavelength and asymmetry are increased because density flows require longer distances to become supercritical again on lower slopes after each successive hydraulic jump bedform morphometry and morphology are used to reconstruct density flow behaviour downslope froude numbers are high near the rollover point and gradually decrease downslope as the slope becomes gentler conversely the specific discharge and flow depth are low near the rollover point and gradually increase downslope as the flow either erodes sediments or becomes more dilute due to sediment deposition and water entrainment the supercritical density flows are believed to be triggered mainly by hyperpycnal flows but some evidence of delta front slope failures is also observed the differences in delta morphology and bedform development between the four deltas are linked to basin morphology and watershed hydrology but also mainly to the fjord heritage of the lakes that allowed the focusing of sediment at the delta front

possible evidence for underlying non linear dynamics in steep faced glaciodeltaic progradational successions steep faced glaciodeltaic progradational successions are often studied in order to reconstruct the behaviour of the glacial feeder system or changes in the sediment sink this paper analyses the magnitude and frequency of depositional events associated with steep faced glacier fed progradational successions recorded in scandinavia and ireland the successions exhibit depositional patterns that may be interpreted as a function of underlying non linear dynamics a number of the sequences display fractal scaling in the frequency and thickness of foreset units other successions demonstrate chaotic patterns and strong relationships between delta front angle and bed thicknesses suggesting that the progradation of such sequences is self organized and to an extent occurs independently of forcing by the feeder system that provides sediment to the delta front these patterns of sedimentation appear to be a function of the steepness of the delta front and or the textural characteristics of the sediment this paper provides further evidence for the simultaneous presence of order and chaos in earth surface processes and calls into question the extent to which palaeoenvironmental reconstructions may be made from steep faced progradational successions copyright 2000 john wiley sons ltd

anisotropic features of geometry and permeability in fractured rock masses abstract a geometric anisotropy factor a f of two dimensional natural fracture systems has been defined according to fracture spacing and orientation in a given direction geometric anisotropy of fracture systems has a major effect on the percolation threshold the critical fracture density of fracture systems below which the overall permeability is zero a two dimensional distinct element code udec has been used to calculate directional flow rates of fracture systems simulated and natural fracture patterns sampled on outcrops in the lake district england have been tested to examine the relation between geometric anisotropy and permeability anisotropy which is demonstrated to have a power law form also the differential anisotropy factor a f results in different universal exponents which govern the relation between fracture density and flow rates

constituent material properties and clast size distribution of volcanic breccia abstract volcanic breccia is a representative heterogeneous rock as a preliminary study for determining its mechanical properties in laboratory and field experiments its material properties and structural features were described three dimensional clast size distribution was also estimated for the study site using the theory of stereology with this distribution determined a numerical simulation was performed to investigate the relationship between the volumetric proportion of clasts in a sample and the areal proportion and maximum length of clasts on a lateral surface of the sample the following observations were made 1 coefficients of variation for volumetric proportion are dependent on the size of the sample and became large when the size of the sample is small 2 samples with a small coefficient of variation can be selected at any size if a restriction is placed on the ratio dmax d0 of the maximum length of clasts to the size of the sample and 3 the volumetric proportion of clasts in each sample can be estimated from the observed areal proportions within an error range that depends on the whole volumetric proportion

the influence of petrophysical properties on the salt weathering of porous building rocks the influence of pore structure water transport properties and rock strength on salt weathering is evaluated by means of a thorough rock characterisation and a statistical analysis the pore structure was described in terms of its porosity pore size distribution quantified by mean pore radius and specific surface area density and water transport was characterised by means of water permeability saturated flow and capillary imbibition unsaturated flow whilst the rock strength test was carried out using uniaxial compressive strength compressional and shear wave velocities dynamic elastic constants and waveform energy and attenuation were obtained from the digital analysis of the transmitted signal a principal component analysis and a stepwise multiple regression model was carried out in order to examine the direct relationships between salt weathering and petrophysical properties from the principal component analysis two main components were obtained and assigned a petrophysical meaning the first component is mostly linked to mechanical properties porosity and density whereas the second component is associated with the water transport and pore structure salt weathering quantified by the percentage of weight loss after salt crystallisation was included in both principal components showing its dependence on their petrophysical properties the stepwise multiple regression analysis found that rock strength has a predominant statistical weight in the prediction of salt weathering with a minor contribution of water transport and pore structure parameters

fan delta sedimentation in the silurian coralliferous formation of sw wales implications for the structure of the southern margin of the welsh basin the uppermost llandovery to lower wenlock coralliferous group in sw pembrokeshire is here redefined as a single formation with two members the coralliferous formation is approximately 150 m thick and comprises a basal unit of granule to pebble grade rudite beds the renney slip member overlain by interbedded mudstones and fine sandstones of the deadman s bay member the renney slip member lies unconformably above the skomer volcanic group and includes 12 4 m of coarse grained granule and pebble rich rudites with beds up to 0 94 m thick three lithofacies are recognized within this unit coarse granule rich rudite beds are interpreted as a variety of mass flow deposits some of which have been reworked in a marine environment thick sandstones with planar and ripple lamination are shoreface to offshore transition zone deposits silty mudstones interbedded with very fine grained sandstones represent marine offshore deposits formed largely below mean storm wave base these facies associations and abundant bioturbation indicate an environment with a strong marine influence and a proximal source of coarse grained sediment the renney slip member is reinterpreted in the context of a fan delta depositional model at least seven cycles of deposition are recognized each showing an upwards fining pattern representing deposition from fan delta shoreface transition zone to open marine environments these patterns of deposition are attributed to localized tectonic movements causing variations in relative sea level at the time the renney slip member was deposited the southern welsh basin margin is interpreted as a fault block extensional margin with the landmass of pretannia to the south though fan delta deposition took place southwards against the uplifted footwall of the wenall fault the basin margin lay to the south of the ritec fault

stratigraphic evolution of a late triassic to early jurassic intracontinental basin in southeastern south china a consequence of flat slab subduction abstract an intracontinental basin formed on a young orogen in south china during the late triassic to early jurassic t3 j1 a 2000 m thick siliciclastic sedimentary succession in the daxi section in northern guangdong province near the depocentre of the basin is correlated with the published zhuyuan section and three other sections the combined daxi zhuyuan sections record a marine influenced deltaic succession of carnian to early toarcian age spanning a period of 55 myr tectonic controls rather than eustasy and climate are interpreted to have played a primary role in the cyclic development of the basin fill four regional scale tectonostratigraphic stages are recognised stage 1 features a retrogradation progradation cycle characterised by increasing then slowly decreasing subsidence rates accompanied by slow to medium sedimentation rates stage 2 is broadly an aggradational cycle with multiple smaller scale retrogradational progradational cycles a complex interplay between moderate subsidence rates high sedimentation rates and eustasy is interpreted for this stage stage 3 represents a retrogradational aggradational progradational cycle during which the impact of global sea level was much reduced this period was characterised by mostly high sedimentation and high subsidence rates but a change to lower subsidence and sedimentation rates took place prior to the intracontinental uplift that inverted the basin stage 4 records continued uplift and the subsequent development of a late jurassic cretaceous basin and range province the temporal spatial evolution of the basin could be best explained by the gravitational pull of a subducted flat slab and its subsequent foundering

water absorption and p wave velocity changes during freeze thaw weathering process of crosscut travertine rocks the turkish travertine is widely used in the domestic and foreign construction industry as slabs and tiles in this study the travertine samples were obtained from four different quarries located in the part of southwestern turkey mineralogical and petrographic properties of the travertine rocks were studied using a polarizing optical microscope and sem the laboratory tests mechanical and physical properties capillary water absorption freeze thaw f t process p wave velocity were performed according to technical specification european standard ts en standards the pore size distribution was determined by means of high pressure mercury porosimetry mip the most of the pores 80 of tested travertine have a pore access diameter of 0 1 m some engineering properties of the rock are severely affected by f t cycles such as ultrasonic p wave velocities water absorption weight and strength the porosity of the travertine presents significantly higher values after the cycles of freeze thaw which also leads to the increase in the absorption by immersion the water absorption method showed that water absorption weight of the specimens varied from 0 32 to 0 88 after the 25 period the freeze and thaw effects of the samples which were tested after exposing to water were measured at a certain time the obtained dry saturated and frozen p wave velocities were examined by the changes of four travertine samples p wave velocity increase is in the range of 4 99 5 97 for tested travertine rocks these studies explain that the p wave velocity changes in freezing travertine exclusively due to changing velocities of pore infill i e water air and ice

standard flow cells to incorporate small scale heterogeneity crossbedding in a reservoir model small scale heterogeneities like crossbedding hamper fluid flow and cause oil to be capillary trapped at the intersections of coarser to finer lamina these effects are fairly well established but less well established is the method to construct an adequate flow cell model containing critical hydraulic properties like bed shape and size lamina shape angle and boundaries nor is it trivial how to obtain those features from well and core we therefore propose to systematically describe geometry and distribution of beds to this end we make use of standard flow cell models that a priori contain all elements and boundaries of beds for a number of bedding types

genesis of an esker like ridge over the southern fraser plateau british columbia implications for paleo ice sheet reconstruction based on geomorphic inversion abstract robust interpretations of meltwater systems operating during ice sheet decay are integral to reconstructing deglacial patterns and style yet over reliance on meltwater landform morphology with limited attention to morpho sedimentary relationships and basin scale geomorphic and stratigraphic context can lead to unreliable geomorphic inversion based paleo ice sheet reconstructions this problem is illustrated by the evolution of young lake esker like ridge yler formed in the young lake basin ylb on bc s southern fraser plateau during decay of the last cordilleran ice sheet cis we integrate data from digital elevation models aerial photographs sedimentary outcrops water wells and shallow geophysics ground penetrating radar electrical resistivity tomography previous interpretations of yler as both an esker and an ice contact poorly sorted stratified deposit emplaced by westerly flowing meltwater imply an eastward retreating ice margin geophysical data from a flat topped component of yler reveal slipface and planar bedded sand and gravel overlying lacustrine sediments characteristic of a hjulstrom delta eastward dipping foresets in a gilbert delta exist at the eastern terminus contextually our observations suggest despite esker like morphology yler was not deposited within a subglacial ice tunnel instead it formed through deposition of subaerial outwash between and or on dead ice in front of a regionally backwasting ice margin the complex deglacial evolution of ylb including a drainage reversal and formation of two glacial lakes supports northwestward backwasting of the cis and dead ice within ylb we conclude that accurate geomorphic inversion of meltwater landforms for deglacial paleo ice sheet reconstruction requires knowledge of landform scale morpho sedimentary relationships and basin scale geomorphic and stratigraphic context

physical deterioration of sedimentary rocks subjected to experimental freeze thaw weathering ten types of sedimentary rock were subjected to repeated cycles of freezing and thawing in addition to monitoring sample weight loss throughout testing a detailed graphic record was made of deterioration mode and its relationship to pre existing rock flaws results suggest that the presence or absence of rock flaws alone does not control deterioration mode but rather that it is the coupled relationship between these flaws and rock strength and textural properties which exerts greatest influence while some pre existing flaws such as syndepositional deformation structures do not appear to influence breakdown others such as incipient fractures cavities and minor lithological boundaries frequently coincide with concentrations of deterioration a characteristic mode of deterioration which is independent of pre existing flaws tends to develop in sandstones indicating the influence in this case of rock texture particularly strong rocks such as crystalline limestone and metasediment tend to fracture preferentially along distinct linear weaknesses such as mineral veins stylolites and incipient fractures particularly weak rocks such as low density chalk break down in a random fashion without regard to pre existing flaws in addition to providing some insight into the role of pre existing flaws in rock deterioration this work also has practical implications for i the study of landform development due to weathering and ii the selection of representative rock samples in durability testing for building stone copyright 2000 john wiley sons ltd

standard facies models to incorporate all heterogeneity levels in a reservoir model abstract the construction of reservoir models is frustrated by the fact that core and well cover only a fraction of the reservoir volume and it is therefore difficult to determine features like facies shape size and distribution inter and intra facies boundaries and lateral trends from them these features are however critical to fluid flow and they should necessarily be incorporated in the reservoir model and we therefore propose to systematically describe geometry and distribution of facies to this end we make use of standard facies models that a priori contain all elements and boundaries of facies for a number of typical depositional environments

river mouth processes in a fjord delta british columbia canada abstract the bella coola delta is a high energy coarse grained fjord delta situated in the coast mountains of british columbia river mouth processes are directly related to the large tidal range 3 9 m mean 5 9 m large which changes the location and nature of distributary mouths producing distinct high tide and low tide outlets frictional forces dominate at high tide as the effluent disperses through five dynamic zones producing a radial bar a friction model applies to this outlet during low tide frictional inertial and buoyant forces and an internal hydraulic jump control the development of six dynamic zones and a lunate middle ground bar a buoyant plane jet model qualitatively best approximates low tide outlet dynamics

the sediment budget and dynamics of a delta canyon lobe system over the anthropocene timescale the rhone river delta lake geneva switzerland france deltas are important coastal sediment accumulation zones in both marine and lacustrine settings however currents derived from tides waves or rivers can transfer that sediment into distal deep environments connecting terrestrial and deep marine depozones the sediment transfer system of the rhone river in lake geneva is composed of a sublacustrine delta a deeply incised canyon and a distal lobe which resembles at a smaller scale deep sea fan systems fed by high discharge rivers from the comparison of two bathymetric datasets collected in 1891 and 2014 a sediment budget was calculated for eastern lake geneva based on which sediment distribution patterns were defined during the past 125 years sediment deposition occurred mostly in three high sedimentation rate areas the proximal delta front the canyon levee system and the distal lobe mean sedimentation rates in these areas vary from 0 0246 m yr 1 distal lobe to 0 0737 m yr 1 delta front although the delta front levees distal lobe complex only comprises 17 0 of the analysed area it stored 74 9 of the total deposited sediment results show that 52 5 of the total sediment stored in this complex was transported toward distal locations through the sublacustrine canyon namely the canyon levee complex stored 15 9 of the total sediment while 36 6 was deposited in the distal lobe the results thus show that in deltaic systems where density currents can occur regularly a significant proportion of riverine sediment input may be transferred to the canyon lobe systems leading to important distal sediment accumulation zones

petrographic quantification of brecciated rocks by image analysis application to the interpretation of elastic wave velocities abstract this paper presents a new procedure to quantify the petrology of materials with complex and heterogenic rock fabric features the classical methodologies for petrographic quantification by image analysis are not appropriate for this kind of rock due to both the high chromatic complexity of these materials and the scale with which the samples are studied the proposed process is particularly interesting for materials with complex chromatic characteristics such as highly fractured rocks concrete etc two commercial varieties of highly fractured brecciated dolostones were selected for this study in order to test the designed methodology this new procedure is based on the analysis process of colour images obtained from mesoscopic sample scanning six petrographic parameters and diagrams have been designed in order to quantify the most influential aspects in compressional v p and shear v s ultrasonic wave propagation these petrographic parameters and diagrams are brecciation density brecciation density map clast size distribution fine grained matrix content shape preferred orientation and rose diagrams the results demonstrate that the proposed methodology is suitable for quantifying the petrography of these kinds of materials furthermore the variations measured in v p and v s are fully explained by the values measured for the following parameters brecciation density fine grained matrix content clast size distribution and preferred orientation of clasts

self organisation fractal scaling and cyclicity in late midlandian glacio deltaic sediments associated with glacial lake blessington co wicklow abstract this paper describes the statistical analysis of the characteristics of foreset beds in glaciodeltaic successions which formed at the margins of glacial lake blessington during the late midlandian glaciation analysis of the foreset bed successions suggests that there are strong statistical relationships between adjacent facies in a number of the successions analysed there is fractal scaling in the thickness and frequency of foreset beds which may indicate underlying non linear dynamics in the behaviour of the ice marginal depositional system while there is evidence that external forcing may be responsible for some aspects of the cyclicity in depositional events at some locations the results presented here suggest that the architecture and facies relationships exhibited by the foreset bed successions may occur as an inherent property of delta front processes independently of external climatic or glacial control

petrophysical properties composition and deterioration of the calatorao biogenic stone case of the sculptures masonry of the valley of the fallen madrid spain the huge sculptures placed outdoors in the valley of the fallen memorial park el escorial madrid made with blocks of black limestone from calatorao zaragoza spain blcz and disposed on a concrete core exhibit weathering traces flaking saline efflorescence and falling fragments currently represent a danger for visitors frost action is important in the valley of the fallen by the large number of freeze thaw cycles produced during sculptures live under a temperate mediterranean climate with severe seasonality the formation of fissures facilitates the water transport within the rock and the salt and ice induced deterioration temperate climates with frequent freezing and thawing cycles can be the most effective drivers of the visible physical weathering in order to propose a suitable weathering model collected black limestones from sculptures and calatorao quarries were analyzed by optical microscopy environmental scanning electron microscopy with energy dispersive spectrometry esem eds inductively coupled mass spectrometry icp ms and x ray diffraction mercury intrusion porosimetry mip nitrogen absorption and helium pycnometry techniques were used for pore analyses of the blcz micro blocks 10 10 10 cm described in terms of pore size distribution pore volume and specific surface area the appreciable amount of organic matter was isolated by solvent extraction acid treatment flotation and perborate degradation followed by gas chromatography mass spectrometry gc ms analytical pyrolysis py gc ms fourier transformed infrared spectroscopy and raman techniques both weathered and fresh blcz samples contained more than 90 calcite shells with circa 10 of pyrite fresh samples or iron hydroxides weathered samples quartz grains claystone and fossil organic matter consisting of a condensed matrix with polyalkyl chains and polycyclic methoxyl lacking aromatic structures the petrophysical analyses revealed volumes of pores sized 0 025 m obtained by n2 adsorption of 3 18 10 3 cm3 g 1 while the measured porosity by mip in the pore range from 0 005 to 200 m was 3 30 10 3 cm3 g 1 these data could be explained by the existence of clay minerals and organic matter in the pore system less than 50 nm of diameter concerning blcz deterioration it was found that the porous framework of blcz was filled with sulphates formed from artificial cement observed in the sculptures inside trough a testing hole and from its intrinsic pyrite the results suggested that although biological processes were not major agents in rock deterioration there was also weak compatibility between sculptures constituents limestone concrete and oxidized iron clamps which under continental mediterranean conditions were continuously releasing weathering compounds accelerating disruption of the cut stone sculptures

a novel 3d geometrical reconstruction model for porous rocks abstract in this paper a novel geometrical reconstruction model is proposed for numerical simulation of pore structure in rocks the spatial configuration and geometrical information of the microstructure are firstly gathered from chongqing sandstone by x ray micro ct observations and experimental tests on chongqing sandstone are applied to obtain the mechanical parameters then on the basis of the gathered geometrical information the surface geometrical model is established by using the modified marching cubes algorithm next the established surface geometrical model is extended to 3d tetrahedral model by using delaunay refinement algorithm finally the 3d tetrahedral model is transformed into finite element fe numerical model moreover the relationship between the porosity fractal dimension of pore structure and mechanical properties of chongqing sandstone is also investigated the comparison of the numerical results and the experimental data shows a good consistency

experimental study on evolution of lacustrine shallow water delta abstract in the process of delta evolution the flow regime and sediment transport change with the development of topography flow is the dynamic factor of shaping topography while sediment scouring and silting is the direct cause of topography formation and they are constrained and influenced by topographic changes simultaneously in order to explore rules of water and sediment movement and topographic sedimentation of delta under microscale conditions we studied the phenomena rules and evolution mechanism of flow movement sediment transport particle sorting topographic sedimentation and flow path generation merger and recombination under microscale conditions from the perspective of physical experiment the influence of different external conditions on lacustrine shallow water delta evolution and the self organization of delta evolution are studied through comparative experiments under the condition of distinct sediment supplied rates or lake levels and repeatability experiments under the same conditions some rules of flow movement sediment transport and topographic sedimentation such as characteristics of each stage during the process of evolution of lacustrine shallow water delta the periodic change of flow regime and the prediction model the characteristics of sedimentary morphology under different conditions and the influence of stochastic factors on delta evolution are summarized the experiments suggest coupled linkage of interaction of water and sediment self organization of flow path evolution and the equilibrium tendency of delta structure under the action of coupling interaction of multiple factors of water sediment and topographic sedimentation

widespread nearshore and shallow marine deposition within the lower jurassic precipice sandstone and evergreen formation in the surat basin australia abstract in the surat basin of eastern australia the lower jurassic precipice sandstone and evergreen formation are a highly prospective reservoir seal pair for notional future carbon capture and storage however the succession remains poorly constrained from a paleodepositional standpoint and this has impacted the capacity to construct predictive reservoir models here we integrate sedimentological ichnological and palynological data from ten cores located across a large region of the northern and central basin to produce conceptual depositional models for the interval our analysis shows that the lower jurassic series consists of fifteen recurring sedimentary facies that are arranged into six facies associations braidplain lower delta plain subaqueous delta delta influenced shoreface tidally influenced shoreline and restricted marine shoals the facies associations occur in the context of large scale fluvio deltaic systems that occupied the basin these results are supported by ichnological indications of marine and brackish water a coastal suite of palynomorphs and marine palynomorphs including rare dinocysts acritarchs and copepod fragments the very low abundance of marine palynomorphs are confined to the upper portion of the evergreen formation and in combination with the sedimentology and ichnology suggest that marine influence increased through time as the basin was filled the elucidation of marine influenced deposition contravenes all but the most recent facies interpretations of the precipice sandstone and evergreen formation and suggests that the paleogeography of the mesozoic of eastern australia needs to be reconsidered importantly the nearshore and shallow marine depositional affinity has important implications for the size orientation and distribution of geobodies when building geologically realistic static reservoir models for dynamic flow simulation

outcrop analog for an oolitic carbonate ramp reservoir a scale dependent geologic modeling approach based on stratigraphic hierarchy considerable effort has been devoted to the development of simulation algorithms for facies modeling whereas a discussion of how to combine those techniques has not existed the integration of multiple geologic data into a three dimensional model which requires the combination of simulation techniques is yet a current challenge for reservoir modeling this article presents a thought process that guides the acquisition and modeling of geologic data at various scales our work is based on outcrop data collected from a jurassic carbonate ramp located in the high atlas mountain range of morocco the study window is 1 km 0 6 mi wide and 100 m 328 1 ft thick we describe and model the spatial and hierarchical arrangement of carbonate bodies spanning from largest to smallest 1 stacking pattern of high frequency depositional sequences 2 facies association and 3 lithofacies five sequence boundaries were modeled using differential global position system mapping and light detection and ranging data the surface based model shows a low angle profile with modest paleotopographic relief at the inner to middle ramp transition facies associations were populated using truncated gaussian simulation to preserve ordered trends between the inner middle and outer ramps at the lithofacies scale field observations and statistical analysis show a mosaiclike distribution that was simulated using a fully stochastic approach with sequential indicator simulation this study observes that the use of one single simulation technique is unlikely to correctly model the natural patterns and variability of carbonate rocks the selection and implementation of different techniques customized for each level of the stratigraphic hierarchy will provide the essential computing flexibility to model carbonate settings this study demonstrates that a scale dependent modeling approach should be a common procedure when building subsurface and outcrop models

capturing and modelling metre scale spatial facies heterogeneity in a jurassic ramp setting central high atlas morocco each simulation algorithm including truncated gaussian simulation sequential indicator simulation and indicator kriging is characterized by different operating modes which variably influence the facies proportion distribution and association of digital outcrop models as shown in clastic sediments a detailed study of carbonate heterogeneity is then crucial to understanding these differences and providing rules for carbonate modelling through a continuous exposure of bajocian carbonate strata a study window 320 m long 190 m wide and 30 m thick was investigated and metre scale lithofacies heterogeneity was captured and modelled using closely spaced sections ten lithofacies deposited in a shallow water carbonate dominated ramp were recognized and their dimensions and associations were documented field data including height sections were georeferenced and input into the model four models were built in the present study model a used all sections and truncated gaussian simulation during the stochastic simulation for the three other models model b was generated using truncated gaussian simulation as for model a model c was generated using sequential indicator simulation and model d was generated using indicator kriging these three additional models were built by removing two out of eight sections from data input the removal of sections allows direct insights on geological uncertainties at inter well spacings by comparing modelled and described sections other quantitative and qualitative comparisons were carried out between models to understand the advantages disadvantages of each algorithm model a is used as the base case indicator kriging model d simplifies the facies distribution by assigning continuous geological bodies of the most abundant lithofacies to each zone sequential indicator simulation model c is confident to conserve facies proportion when geological heterogeneity is complex the use of trend with truncated gaussian simulation is a powerful tool for modelling well defined spatial facies relationships however in shallow water carbonate facies can coexist and their association can change through time and space the present study shows that the scale of modelling depositional environment or lithofacies involves specific simulation constraints on shallow water carbonate modelling methods

shoal water deltas in high accommodation settings insights from the lacustrine valimi formation gulf of corinth greece the stratigraphic architecture of shoal water deltaic systems developed in low accommodation settings is relatively well known in contrast the features of shoal water deltas developed in high accommodation settings remain relatively poorly documented especially when compared with the available data sets for gilbert type deltaic systems developed in the same settings the lacustrine valimi formation gulf of corinth greece provides an opportunity to investigate the facies assemblage and architectural style of shoal water deltaic systems developed in high accommodation settings the studied interval accumulated during the pliocene and pleistocene and represents part of the early syn rift gulf of corinth succession six facies associations each described in terms of depositional processes and geometries have been identified and interpreted to represent a range of proximal to distal deltaic sub environments delta plain distributary channel mouth bar delta front prodelta and open lake the facies associations and their architectural elements reveal characteristics which are not common in traditionally described shoal water deltas of note different facies arrangements are observed in the distributary channels in different sectors of the delta passing from thick single storey channel fills embedded within delta plain fines in landward positions to thin amalgamated and multi storey channels closer to the river mouth this study proposes a new depositional model for shoal water deltas in high accommodation settings documenting for the first time that shoal water delta deposits can form a substantial part of stratigraphic successions that accumulate in these settings the proposed depositional model provides new criteria for the recognition and interpretation of these deposits the results of this study have applied significance for reservoir characterization

discontinuous drainage systems formed by highland precipitation and ground water outflow in the navua valles and southwest hadriacus mons regions mars abstract the navua valles are systems of paleodrainages located north of dao vallis which empty into hellas planitia the largest impact basin on mars in this study we mapped and characterized the navua valles region s individual drainage systems including drainages along the southwestern flank of hadriacus mons and one valley network from the same source as navua valles but flowing in the opposite direction the major drainage systems share morphological characteristics common to both outflow channels and valley networks the slopes in this region are dissected by two major navua drainage systems here navua a and b and several shorter sub parallel valleys formed on the highest gradient approximately 20 m km 1 15 slopes at the lowest part of hellas basin s rim the two major drainage systems originate in the highlands and empty into the basin our mapping suggests that water in navua valles reached the basin floor in a complicated descent and included several episodes of surface ponding surface runoff infiltration subsurface flow and subsequent outflow the most prominent channel system navua a forms a repetitive sequence of deep incision into bedrock followed by a transition into broad channels in erodible materials and then into unconfined deposits this successive erosion transport deposition sequence continues to repeat along the valley s entire length forming a discontinuous pattern that is consistent with classical fluvial process models the channels cut into volcanic plains likely emplaced from the formation of tyrrhenus and hadriacus montes the dendritic source valleys of navua a originate from the rim of a highland crater while the rest of this subsystem consists of a single discontinuous channel which is consistent with a single water source zone that likely supplied water for all channels downslope these drainages may have formed as discontinuous channels revealing the potential existence of subsurface drainage pathways located within an approximately 1 5 10 5 km 2 area water transported underground emerged in segments that are either isolated or aligned downslope from each other we have identified several causes of discontinuities located the zones of potential ground water discharge and recharge and a site of localized precipitation at the headwaters of navua a

fracture pattern analysis as a tool for constraining the interaction between regional and diapir related stress fields poza de la sal diapir basque pyrenees spain during diapir evolution the local stress field results from the interaction between diapirrelated and remote regional stress fields the fracture pattern hosted in the overburden can register this evolving interaction providing significant insights for the unravelling of the diapir kinematics in this work we present the example of the poza de la sal diapir which is a salt diapir that pierces the synorogenic deposits of the basque pyrenees the integrated analysis of mesostructural data which includes field collected faults joints and fracture traces digitalized on high resolution orthophotos allowed us to establish an evolutionary model for the stress field around diapirs the presented data support the idea that during diapir evolution stress fields evolve from mostly regional related to mostly diapir related contrasting with other geological data seismic data geological map and cross section we observe that different methods provide complementary information coherent with the proposed evolutionary model of the poza de la sal diapir the study of fracture development associated with the growth of salt diapirs is of interest for both academic and industrial purposes in fact fractures play an important role in fluid flow and its accumulation in salt diapir related reservoirs johnson bredeson 1971 koestler ehrmann 1987 davison et al 2000a b on the other hand the analysis of fracture patterns is useful to constrain the host structure evolution thorbjornsen dunne 1997 tavani et al 2008 and accordingly can provide useful information for understanding diapir kinematics alsop 1996 stewart 2006 yin groshong 2007 yin et al 2009 the fracture pattern associated with salt diapirs and in general with doming structures is characterized by two classes of elements radial and concentric fig 1a b e g parker mcdowell 1955 withjack 1979 squyres et al 1992 branney 1995 malthe sorenssen et al 1999 rowan et al 1999 2003 davison et al 2000a b freed et al 2001 stewart 2006 this pattern is documented in simple structures where the remote stress field is negligible in relation to the diapir related stress fields when such a condition is not verified the interaction of these two stress fields leads to the development of more complex patterns ode 1957 withjack scheiner 1982 studies of interacting regional and punctual stress fields e g ode 1957 indicate that the influence of diapir induced stress progressively reduces away from the dome i e the punctual structure as a consequence far from the diapir the fracture pattern responds to the remote stress field and approaching the diapir the fracture pattern tends to be radial and concentric fig 1c although these patterns have been observed by several authors in different structures withjack scheiner 1982 mege masson 1996 ernst et al 2003 there are no detailed field studies focusing on this topic in this work we present a simple 2d theoretical stress field model where the stress tensor resulting from the interaction between remote and diapirrelated stress fields is assumed to be for a fixed distance from the diapir centre a 2 2 matrix provided by the sum of the horizontal components of the two stress tensors the eigenvectors associated with this matrix are assumed to be the principal axes of the local stress field the working hypothesis is that if the stress field changes the azimuth of fractures joints developed under these stress fields also change by understanding interactions between diapir related and regional stress fields we can predict the azimuth of the developed fractures to test the validity of this theoretical model we have applied it to a well exposed salt diapir located at the western pyrenees poza de la sal diapir this is a near circular diapir with a mainly carbonate overburden affected by a complex pattern of fractures results of this comparison indicate that despite its simplicity the provided stress model is a useful tool for understanding the kinematics of salt diapirs accordingly in this paper we provide from alsop g i archer s g hartley a j grant n t hodgkinson r eds 2012 salt tectonics sediments and prospectivity geological society london special publications 363 521 532 http dx doi org 10 1144 sp363 25 the geological society of london 2012 publishing disclaimer www geolsoc org uk pub ethics guidelines to obtain a fracture pattern using the theoretical model presented to complement other techniques of investigation such as field work or 3d seismic interpretations

the myth of the messinian dardanelles late miocene stratigraphy and palaeogeography of the ancient aegean black sea gateway abstract the dardanelles region has formed a key gateway connecting the eastern paratethys and the aegean mediterranean since the late miocene its sedimentary sequences contain crucial information about connectivity and tectonics but so far lack unambiguous age constraints only a few miocene marine episodes have been documented and fossil assemblages are predominantly composed of paratethyan fauna mollusks and ostracods here we apply an integrated stratigraphic approach and use the recently established chronostratigraphy for the eastern paratethys to re evaluate the faunal assemblages and palaeoenvironments of the seddulbahir and intepe sections that allegedly played a crucial role in the geodynamic evolution of the dardanelles during the messinian zanclean the paratethyan ostracods and mollusks however clearly indicate that these sections correspond to the middle tortonian 9 ma bessarabian khersonian in eastern paratethys terminology nannofossil assemblages are dominated by a mixing of reworked taxa from the late eocene and oligocene and no age diagnostic taxa have been observed dinoflagellate analyses are also hampered by reworking and mainly reveal non marine fresh to oligohaline aquatic conditions fossil mammal remains in the seddulbahir section and other localities in the region confirm the late miocene age strontium 87sr 86sr isotope ratios of the anomalohaline brackish ostracods are significantly below open ocean values and similar to values obtained from khersonian ostracods of bulgaria fresh water assemblages reveal much higher 87sr 86sr values which are interpreted to reflect the composition of local rivers we conclude that in late miocene times the dardanelles region was a fresh to anomalohaline embayment ephemerally connected to the eastern paratethys we found no evidence for a major messinian erosional surface nor for marine mediterranean fossils indicative of the early zanclean our results furthermore indicate that the proposed messinian age for the propagation of the north anatolian fault into the dardanelles region must be revised

rock fabric pore geometry and mineralogy effects on water transport in fractured dolostones abstract the combined influence of rock fabric pore geometry and mineralogy petrological parameters on transport properties in complex and heterogeneous naturally fractured rocks was studied experimentally as fissure geometry quantification has rarely been addressed in most theoretical studies of transport properties emphasis was placed on the effects of fissure geometry on both non saturated media capillary rise and saturated media permeability we proved that prediction of transport properties in complex rocks is not guaranteed by the estimation of the classic micro structural variables considered in the literature and that accurate prediction can only be attained when petrological parameters are first quantified in depth and then combined principal component analysis and the regression models proposed here clearly demonstrated on the one hand that a meaningful porous network in non saturated media must be modelled with a combination of different geometrical capillary tubes representing the matrix cylindrical and the fissure rectangular prism and on the other hand that in saturated media a well in deep fissure size quantification enabled a more accurate prediction of permeability to be made the experimental data confirm that transport properties and its anisotropy are closely dependent on fissure typology textural characteristics mineralogy and spatial distribution of the whole rock fabric elements enlarged fissures weakly exert capillary suction due to the retarding effect of gravitational forces but they are vital in controlling permeability cracklebreccias with small clasts high dolomite cement content and high inter clast fissure density exhibit strong capillary suction however high calcite cement produces abnormally low rates of capillary rise due to possible pore surface contamination together with a high contact angle effect good agreement between permeability and geometric factors provided a suitable basis for identifying preferred permeable directions additionally we found a critical fissure density which defined the isotropic matrix permeability we also present a new practical and simple linear model relating permeability to capillarity with meaningfully and easily estimated petrological parameters results obtained in the present study demonstrated the correct identification and use of more directly related petrological variables for modelling transport properties moreover the analysis of these results using multivariate analysis is considerably more demanding compared to the conventional approaches

predicting water permeability in sedimentary rocks from capillary imbibition and pore structure this study was financed by the spanish ministry of science and innovation cgl2011 25162 a pre doctoral research fellowship was awarded to c pla for this project

fan deltas and braid deltas varieties of coarse grained deltas two types of coarse grained deltas are recognized fan deltas and braid deltas fan deltas are gravel rich deltas formed where an alluvial fan is deposited directly into a standing body of water from an adjacent highland they occupy a space between the highland usually a fault bounded margin and the standing body of water in contrast braid deltas here introduced are gravel rich deltas that form where a braided fluvial system progrades into a standing body of water braid deltas have no necessary relationship with alluvial fans as exemplified by fluvioglacial braid deltas braid deltas have previously been classified as fan deltas even though the geomorphic and sedimentologic settings of the two systems can be vastly different braid deltas are a common present day geomorphic feature and are abundant in the geological record fan deltas and braid deltas can be distinguished in the rock record by distinctive subaerial components of these depositional systems the shoreline and subaqueous components of both are similar fan delta sequences have a subaerial component that is an alluvial fan facies comprising interbedded sheetflood debris flow and braided channel deposits fan deltas produce small a few tens of square kilometres wedge shaped bodies of sediment commonly displaying high variability in paleocurrent patterns and abrupt changes in facies the deposits are generally very coarse grained with large out sized clasts very poorly sorted matrix rich polymictic heterolithic partially cemented by penecontemporaneous carbonate and have low porosity and permeability braid deltas in contrast have a subaerial component consisting entirely of braided river or braidplain facies their deposits display better sorting roundness and clast orientation than do fan delta sediments they lack a muddy matrix they display size grading and bar migration they commonly have a sheet geometry with high lateral continuity tens to hundreds of square kilometres and they exhibit moderate to high porosity and permeability valuable paleogeographic and tectonic information concerning the proximity of highlands and major fault zones may be misinterpreted or lost if these two coarse grained deltaic systems are not differentiated

flume tank study of surface morphology and stratigraphy of a fan delta the morphodynamics of a river flood on a fan delta and its resultant stratigraphic and sedimentary signatures have been studied by means of a flume experiment under controlled boundary conditions the experiment revealed that deposition was dominant in flood periods when the channels were highly loaded with sediments in contrast erosion was dominant in periods of low flow mouth bars were formed when a subaqueous channel began to backfill the development of a mouth bar began with progradation in the down dip direction and proceeded by aggradation then retrogradation and finally transverse growth a channel bifurcated in multiple stages by sequentially forming mouth bars or by simultaneously forming arrays of mouth bars during the bifurcation the diffluent point moved upstream which resulted in channel migration and the development of a delta lobe flood events triggered fan delta front slide slump deposits

middle pleistocene lacustrine deposits in eastern essex england and their palaeogeographical implications investigations in quarry exposures in the asheldham gravel and related deposits of southeast essex are described section logging mapping and borehole investigations are supported by clast lithological heavy and clay mineralogical determinations the sediments are derived from reworking of local thames basin materials fine sediment being predominantly from the london clay the sequence is shown to represent an aggradation that began as the fluvial infilling of the river medway valley the river thames diverted into this valley by glaciation further west overwhelmed the medway reworking the deposits the valley was subsequently drowned and fine laminated lake sediment was initially deposited this was during a period when the valley was drowned by the glacial lake ponded in the southern north sea basin by the anglian elsterian ice sheet progradation by a braid delta complex advanced along the valley and subsequently fluvial deposition returned valley widening and straightening accompanied the delta progradation the deposits were dissected by deep fluvial valleys infilled by hoxnian interglacial sediments the asheldham gravel is therefore placed in the anglian elsterian stage

cryogenic powderization of triassic dolostones in the buda hills hungary disintegration of dolostones to dolomite powder powderization was a widespread phenomenon in triassic dolostones of the buda hills where the areal extent of powdered dolostones is large compared to similar occurrences elsewhere in the world in the buda hills dolostone disintegration proceeded in four stages that correspond to a gradual decrease in particle size that is from the parent dolostone to 1 crackle breccia via 2 mosaic breccia diameter 2 cm via 3 mosaic breccia blocks floating in dolomite powder to 4 dolomite powder diameter 100 300 m stable isotope ratios and trace element compositions of dolomite remained constant throughout these stages and there are no indications of dissolution in most locations suggesting that disintegration was predominantly a mechanical process combining these findings with the geological history of the region and supported by a simple freezing thawing experiment and pertinent experimental studies on weathering of building stones it appears that powderization in the buda hills was caused by repeated freeze thaw cycles during and or after the pleistocene glaciations subaerial exposure under cold climate conditions involves multiple freeze thaw cycles that create mechanical stresses in the rock framework related to the opposing thermal expansion of rock and water that freezes and of ice that liquefies this process is herewith called cryogenic powderization our data further suggest that the synergy of four factors promoted dolostone powderization in the buda hills 1 tectonics which created a pervasive fracture network 2 intercrystalline porosity of the dolostone 3 relatively high water saturation and 4 subaerial exposure under cold climate conditions

sedimentary facies and depositional architecture of ice contact glaciomarine systems abstract the characteristics of ice contact glaciomarine systems are reviewed based on a range of weichselian and holocene examples from the fjordal basins in norway and svalbard these depositional systems occur as large morphological ridges end moraines including push moraines which are coarse grained and show large scale foreset bedding the paper addresses some of the major problems with regard to the recognition classification and stratigraphic analysis of these systems the ice proximal glaciomarine systems are classified here into three categories 1 ice contact submarine fans 2 ice contact deltas and 3 glaciofluvial deltas this classification integrates morphological and sedimentological criteria and renders these glaciomarine systems not only easier to recognize in the stratigraphic record but also possible to compare with common non glacial deltaic systems the emphasis is on the criteria for the recognition of the ice contact glaciomarine systems i e ice contact fans and ice contact deltas and their discrimination from common gilbert type deltas and fan deltas the review further focuses on ice contact glaciomarine systems as highly sensitive recorders of glacier dynamics and climatic fluctuations it is shown that both the periods of ice front stability and changes in the ice front position as well as the magnitude and rate of those changes are all recorded in the ice contact depositional system the sedimentary record further reflects glacio isostatic sea level changes and local palaeogeography a new conceptual model is suggested which places these ice contact glaciomarine systems in a dynamic stratigraphic context the model integrates sedimentary facies and their depositional architecture in an allostratigraphic framework and is meant to be a guide for the analysis of the sedimentary record of ice contact systems

interrelations of the petrophysical sedimentological and microstructural properties of the oolithe blanche formation bathonian saline aquifer of the paris basin abstract the paris basin seems a suitable location for co2 capture and storage given both the amount of co2 produced and the availability of depleted fields and deep saline aquifers this study investigates the petrophysical properties in relation to the sedimentary and diagenetic environment of the oolithe blanche formation middle jurassic a deep saline aquifer considered a potential candidate for co2 storage because of the scarcity of core data in the paris basin our investigation was based on the study of field analogues in the south east part of the paris basin the oolithe blanche formation bathonian is 70 80 m thick eighteen oriented blocks were collected from three outcrops selected for the different sedimentological facies identified in the formation their petrophysical properties were measured porosity pore size distribution derived from mercury injection tests permeability and capillary imbibition parameters the sedimentary and diagenetic facies were defined by using optical microscopy coupled with image analysis on thin sections and sem the oolithe blanche formation is composed of oolitic and bioclastic limestones deposited in a shallow marine setting three main sedimentological facies were defined the oolitic shoal facies the tide dominated facies and the prograding oolitic facies they exhibit subtle variations in composition and in the distribution of carbonate textures porosity measured using the water saturation triple weight method ranges from 6 to 34 permeability values are low between 0 1 md and 9 md the data from mercury intrusion porosimetry show that the distribution of the pore throat diameter is either unimodal microporosity only or bimodal macro and microporosity microporosity is intraparticle intraooid and macroporosity is interparticle and is related to dolo dedolomitization variations of petrophysical parameters can be explained by the microstructure now these latter results calibrated by studying field analogues must be extended to borehole data and core data to optimize our knowledge of the deep saline aquifer of the oolithe blanche formation without such investigations it will be impossible to estimate the suitability of this deep saline aquifer for co2 storage

the link between tectonics and sedimentation in asymmetric extensional basins inferences from the study of the sarajevo zenica basin abstract the coupled tectonic and depositional history of extensional basins is usually described in terms of stratigraphic sequences linked with the activity of normal faults this depositional kinematic interplay is less understood in basins bounded by major extensional detachments or normal fault systems associated with significant exhumation of footwalls of particular interest is the link between tectonics and sedimentation during the migration of normal faulting in time and space across the basin one area where such coupled depositional kinematic history can be optimally studied is the late oligocene miocene sarajevo zenica basin located in the dinarides mountains of bosnia and herzegovina this intra montane basin recorded oligocene pliocene sedimentation in an endemic and isolated lake environment we use field kinematic and sedimentological mapping in outcrops correlated with existing local and regional studies to derive a high resolution evolutionary model of the basin the novel results demonstrate a close correlation between moments of normal faulting and high order sedimentological cycles while the overall extensional basin was filled by a largely uni directional sediment supply from the neighbouring mountain chain the migration in time and space of listric ne dipping normal faults was associated with a gradual shift of the sedimentological environment transgressive regressive cycles reflect sequential displacements on normal faults and their footwall exhumation defining a new sedimentological model for such basins this early middle miocene extension affected the central part of the dinarides and was associated with the larger opening of the neighbouring pannonian basin the extension was preceded and followed by two phases of contraction the oligocene early miocene thrusting took place during the final stages of the dinarides collision while the post middle miocene contraction is correlated with the regional indentation of the adriatic continental unit this latter phase inverted the extensional basin by reactivating the inherited basal listric detachment

capillary water absorption characteristics of some cappadocian ignimbrites and the role of capillarity on their deterioration cappadocia stands out as one of the most important regions in turkey for its natural historical and cultural heritages the region is under the influence of wetting and drying and freezing and thawing weathering processes which are largely controlled by the water content water migrates through rock pores via different processes such as capillary water absorption which is one of the most common ways observed in the cappadocia region in this study a research program consisting mainly of laboratory studies was carried out to investigate the capillary water absorption characteristics of ignimbrites which are the host rocks of many natural and historical heritage structures in cappadocia accordingly xrd analyses mercury porosimeter and capillary water absorption tests were performed the pore size distribution which is a function of welding degree controls the capillary water absorption process of ignimbrites particularly ignimbrites that have a uniform pore size distribution of around 5 10 m reveal higher capillary water absorption potential ignimbrites have a considerable and variable potential in terms of capillarity and the capillarity plays a major role on the deterioration and decomposition of many of the historical and natural heritage structures in the cappadocia region

experimental studies on ignimbrite and the effect of lichens and capillarity on the deterioration of seljuk gravestones abstract ignimbrites are used extensively in masonry and decorative cladding not only in historical structures but also in residential houses recently as well as monuments around ahlat bitlis turkey region because of their light weight softness and insulating properties the most famous architectural monument is the ahlat seljuk tombs in which ignimbrites were used for the structure these are thousand year old gravestones that have been subjected to significant degradation over time caused by many physical and chemical effects the aim of this study is revealing the mineralogical petrographical petrophysical and mechanical properties of fresh ignimbrites as well as determining the effect of lichens and capillarity on the deterioration of seljuk gravestones in accordance with laboratory studies and field observations a total of four different ignimbrite levels have been evaluated which are widespread in the region and named as n1 reddish brown n2 dark brown n3 yellowish gray and n4 black respectively among these ignimbrites the samples of n1 and n2 were employed in the construction of seljuk gravestones the lithic material content and welding degree are the main controlling factors of the engineering properties of ignimbrites laboratory test results indicate that high porosity of ignimbrites and transport of water mediated by capillarity accelerate the deterioration of ignimbrites furthermore lichens play a preventive role in the deterioration mechanism of ignimbrites rather than disintegrating the tombstones

outcrop architecture of a fluvio lacustrine succession upper triassic yanchang formation ordos basin china abstract although several studies have considered the sedimentary facies of the upper triassic yanchang formation in terms of their hydrocarbon potential in the petroliferous ordos basin such studies have mostly interpreted subsurface data and few have systematically examined the detailed outcrop based anatomy of this succession this study characterizes a series of well exposed outcrop sections along an 80 km long e w oriented series of road cuttings in the southeast ordos basin to reconstruct the sedimentary architecture of a fluvio lacustrine succession and determine the principal controls that governed the style of accumulation and preservation the yanchang formation is divided into 10 depositional units chang 10 base to chang 1 top that record the sedimentary evolution of a series of large scale fluvial systems that constructed delta front and pro delta bodies as they entered a large interior draining lake detailed analysis of the internal architectures of the delta front bodies records the mechanism of growth of a large scale shallow water delta succession lacustrine subaqueous distributary channels are composed of 3 15 m thick sandstone fills such channelized bodies are highly elongate and many can be traced several kilometres such bodies can be shown to be commonly associated with thin bedded mouth bar and subaqueous interdistributary bay deposition the progradational architecture of the delta front elements is difficult to recognize on outcrop scale deposits of the chang 10 to 1 units record 4 major lacustrine transgressive regressive cycles during the late triassic transgressive events are signified by the widespread occurrence of 10 20 m thick oil shale prone intervals regressive events are signified by the progradational stacking towards the basin centre of sandstone prone facies associations mainly accumulated in fluvial channel delta plain and upper delta front environments the uppermost chang 1 interval records late stage filling of the lacustrine basin the transgressive regressive cycles equate to sequences that can be correlated across the region development of which was controlled by a combination of changes in the rate of tectonic subsidence the rate of sediment delivery from the basin margin hinterland and climate factors that were themselves influenced by intracontinental growth of the neighbouring qinling orogen

basin sedimentation and the growth of prograding deltas a theoretical model is developed for the infilling of a basin by the progradation of a delta the model simulates four mechanisms for the transfer of sediment from the land to the sea 1 bed load dumping along the delta front 2 hemipelagic sedimentation under the seaward flowing river plume 3 proximal slope bypassing by turbidity currents and 4 the combined effects of both short term wave and tidal action and long term creep and small slides downslope diffusion of the accreting sediment mass the general model is of relatively low precision useful for predicting basin infilling on time scales greater than a few hundred years the river plume portion of the model can predict sedimentation on time scales of less than a year and is designed to reflect the dynamics of a free two dimensional buoyant jet that transports a composite size population of suspended particles the general model allows the prediction of lithologies changing with time and space the model has been used to simulate infilling processes for knight and bute inlets two grabenlike fjord basins along the coast of british columbia model simulations of delta progradation over the last 10 000 years favorably predicted the modern seafloor bathymetry and sediment accumulation rates to within a factor of 2 of measured 210pb 137cs and sediment trap rates

multi scale three dimensional distribution of fracture and igneous intrusion controlled hydrothermal dolomite from digital outcrop model latemar platform dolomites northern italy abstract in recent years fracture controlled hydrothermal dolomitization in association with igneous activity has gained interest in hydrocarbon exploration the geometry and distribution of dolomite bodies in this setting are of major importance for these new plays the latemar platform presents a spectacularly exposed outcrop analogue for carbonate reservoirs affected by igneous activity and dolomitization light detection and ranging lidar scanning and digital outcrop models doms of outcrops offer a great opportunity to derive geometrical information only a few analysis methods exist to quantitatively assess huge amounts of georeferenced three dimensional lithology data this study presents a novel quantitative approach to describe three dimensional spatial variation of lithology derived from doms this approach is applied to the latemar platform to determine dolomite body geometry and distribution in relation to crosscutting dikes a high resolution photorealistic dom of the latemar platform allows description of dolomite occurrences in three dimensions with high precision at platform scale this results in a unique lithology dataset of limestone dolomite and dike positions this dataset is analyzed by true three dimensional variography for the geospatial description of dolomite distribution in most studies three dimensional geostatistics is the combination of two dimensional horizontal and one dimensional vertical variation in this study the dolomite occurrences are extensive in three dimensions and cannot be reduced to a two dimensional one dimensional case therefore the concept of two dimensional variogram maps is expanded to a three dimensional description of lithology variation three dimensional anisotropy detection is used to derive principal directions in the occurrence of dolomite two small scale

coalesced delta front sheet like sandstone bodies from highly avulsive distributary channels the low accommodation mesa rica sandstone dakota group new mexico u s a