lovehovden fault and billefjorden rift basin segmentation and development spitsbergen norway the carboniferous billefjorden rift basin is a well known example of a suite of carboniferous basins on the barents shelf and ne greenland the basin has a clastic carbonate and evaporite fill with complex and disputed stratigraphic relationships especially regarding the ebbadalen and minkinfjellet formations geometrically the basin is considered a simple half graben a n s trending fault and monocline structure within the northern portion of the basin the lovehovden fault has lithological and thickness differences across it within the minkinfjellet and possibly ebbadalen formations the fault shows w side down movement defining a sub basin within the larger half graben significant along strike changes occur down throw to the west is at least 150 metres and possibly 400 metres as shown by across fault thickness differences of ebbadalen and or minkinfjellet formations to the east of the fault the contact between the ebbadalen and minkinfjellet formations is a disconformity with significant local relief and is interpreted to represent exposure from footwall uplift and associated near or at surface solution producing basal stratiform breccias a similar contact is not exposed west of the fault monoclinal deformation and thickening of the younger wordiekammen formation above and across the monocline constrain a later movement component kinematic data and the structural style clearly indicate the lovehovden fault is a normal fault with associated tri shear zone development consistent with the regional carboniferous rift setting earlier interpretations describe the lovehovden fault and monocline as tertiary contractional features in contrast our work advocates that they are an important architectural basin element defining a sub basin within the billeforden trough during minkinfjellet formation deposition with insignificant if any tertiary reactivation the lovehovden fault is aligned with and represents the southern termination of the lemstromfjellet fault to the north thus the billefjorden basin changes from a narrow graben to a broader half graben to the south these along strike changes have important implications for the stratigraphic architecture of the basin and for palaeogeographic reconstructions these results and application of 3 d models for extension related tri shear zones may help inform interpretation of other carboniferous basins on the barents shelf

development of incisions on a periodically emergent carbonate platform natih formation late cretaceous oman abstract subaerial exposure of carbonate platforms is generally recorded by karstification and pedogenesis whereas erosion features such as incisions along emersion surfaces have seldom been observed and studied however the recognition of incisions and the characterization of their fill may facilitate definition and hierarchy of sequence boundaries especially along exposure surfaces that do not otherwise present clear petrographic evidence for emersion in the natih formation late albian early turonian oman two successive incision surfaces are present in the upper part of the first third order depositional sequence seismic interpretation of regional subsurface data has allowed the quantification of progradational geometries within the natih sequence i carbonate platform and the correlation of incision surfaces with forced regressive prograding wedges on the margins of the intrashelf basin detailed geological sections and correlations have been made from three outcrop localities allowing a precise description of geometries and facies of incision fills morphology orientation and extent of these incisions have been assessed from detailed seismic interpretation coupled with forward seismic modeling the integration of outcrop and seismic data sets at the regional and local scales allows the interpretation and discussion of the origin and factors controlling the development of these incisions and a refinement of the stratigraphic model these two incisions record rapid sea level variations 500 ky with a magnitude of approximately 20 and 30 m that occurred during the early cenomanian this is probably not a unique case since for the same time interval incisions have been observed in siliciclastic systems in western canada and india and in carbonate systems on the arabian plate

localisation of normal faults in multilayer sequences abstract existing conceptual growth models for faults in layered sequences suggest that faults first localise in strong and brittle layers and are later linked in weak and ductile layers we use the discrete element method for modelling the growth of a normal fault in a brittle ductile multilayer sequence the modelling reveals that faults in brittle ductile sequences at low confining pressure and high strength contrast localise first as mode i fractures in the brittle layers low amplitude monoclinal folding prior to failure is accommodated by ductile flow in the weak layers the initially vertically segmented fault arrays are later linked via shallow dipping faults in the weak layers faults localise therefore as geometrically and kinematically coherent arrays of fault segments in which abandoned fault tips or splays are a product of the strain localisation process and do not necessarily indicate linkage of initially isolated faults the modelling suggests that fault tip lines in layered sequences are more advanced in the strong layers compared with weak layers where the difference in propagation distance is most likely related to strength and or ductility contrast layer dependent variations in fault localisation rates generate fringed rather than smooth fault tip lines in multilayers

pull aparts shear fractures and pressure solution vein arrays are often composed of pull aparts which are linked by shear fractures good examples of which occur in the lower jurassic limestones of somerset southwestern england such pull apart arrays have displacement distance characteristics which are similar to fault zones with maximum displacement indicated by the largest pull apart widths near the centre of the array and with displacement decreasing towards the tips pull apart arrays usually die out into enechelon or pinnate veins evidence for pressure solution along the shear fractures which connect pull aparts include their dark and braided nature their obliquity to the displacement direction the high dihedral angles often 90 between conjugate shear fractures and the dissolution of earlier structures a range of geometries occurs with varying relative amounts of veins and pressure solution being related to varying amounts of transtension or transpression there is a general trend for an increase in the angle between vein segments and the shear fractures as contraction increases there is therefore a trend for increased pressure solution on the shear fractures in more contractional arrays the concentration of insoluble material along shear fractures has important implications for the mechanics and sealing of faults

uplift deformation and fluid involvement within an active normal fault zone in the gulf of corinth greece the active pisia fault zone is exposed close to the crest of a rotated carbonate fault block that forms part of the southern margin to the gulf of corinth half graben in central greece the crest of the fault block lies above sea level whilst in the hanging wall a marine basin exists as a result the diagenetic and structural characteristics of the fault zone record complex fluid involvement both early phreatic carbonate syn kinematic cements characterized by drusy fabrics baroque dolomites and crack seal textures and late vadose carbonate syn kinematic cements characterized by flowstones containing cave collapse debris exist in the uplifted footwall to the fault downward percolation of vadose meteoric waters and the upwelling of pore waters with elevated temperatures produced the diagenetic features observed within the fault zone the co existence of early phreatic and late vadose cements within the fault zone is related to footwall uplift across the water table and subsequent erosional unroofing the present day elevation of phreatic cements to c 650m above current sea level provides a minimum estimate of footwall uplift along the fault the wider implication is that temporal changes in deformation and fluid flow may typify fault block evolution

dynamic development of fault rocks in a crustal scale detachment an example from western norway 1 the nordfjord sogn detachment nsd zone of western norway juxtaposes eclogites and gneisses of lower crustal affinity with sedimentary deposits suggesting that the zone experienced substantial displacement during devonian extensional denudation of the caledonides renewed activation occurred in permian and jurassic cretaceous times the detachment zone consists of a succession of fault related rocks reflecting various crustal positions and deformation mechanisms during activation and unroofing in more detail the lower 1 2 km thick section of the nsd zone consists of mylonites with various protoliths showing a general upward decrease in metamorphic grade the mylonitic section is truncated by the nsd fault defining the boundary toward hanging wall nappe rocks that are topped by sedimentary basins in an attempt to provide precise descriptions of the observed fault rocks we classify these rocks into 1 noncohesive breccias 2 cemented and indurated breccias of secondary cohesion and 3 cataclasites phyllonites and mylonites formed with primary cohesion along and across strike sections of the fault reveal the spatial and temporal relationships of the nsd fault the fault zone consists of a lower section of phyllonites and cataclasites reaching a total thickness of 50 70 m significant volumes of pseudotachylyte were injected into these fault rocks and were later reworked reactivation of the fault is suggested by overprinting carbonate cemented breccias that are cut by a discrete fault itself associated with breccias and gouge by comparing the various fault rocks and their formation mechanisms some constraints can be applied to the unroofing history the nsd fault developed in the ductile brittle transition zone of the crust where it experienced an initial shift from mainly frictional to plastic flow caused by reaction softening before hardening caused a return to frictional flow at the same time repeated pulses of pseudotachylyte were generated possibly lubricating the fault zone and contributing to strain localization these pseudotachylyte pulses also show that the fault was affected by seismic slip events before returning to a creep regime within a wider section than that ruptured by earthquakes younger cemented breccias and noncohesive breccias and gouge reflect earthquake rupturing and frictional flow within the seismogenic crust

identification of a suspected quaternary fault in eastern korea proposal for a paleoseismic research procedure for the mapping of active faults in korea abstract in terms of seismic hazard in the korean peninsula the occurrence of destructive earthquakes has long been overlooked because of no serious modern instrumental seismicity and lack of historical earthquake records of large earthquakes in recent years although the importance and uses of paleoseismological studies has significantly increased in seismic hazard assessments of critical facilities there is still a huge lack of paleoseismological data to improve our knowledge for korean active tectonics and relevant seismic hazards in this study we identified and characterized a suspected quaternary fault in the eastern part of the korea peninsula based on lineament analyses field observations and trench surveys we focus on a prominent lineament around the northern part of the previously reported but not sufficiently studied maeup fault firstly a potential fault lineament is recognized by geomorphic expressions in a mountainous area from satellite and digital elevation model dem generated images then fault related geomorphic and hydrologic features such as disconnected drainages sag ponds and asymmetric water leaking out on an artificial ditch were observed along the lineament in the field studies finally the existence of the fault is confirmed by an exposure of a 2 5 m wide fault core in trench surveys the internal structures of the fault core i e slip surfaces slickenlines and s c fabrics indicate that the fault evolved via a series of slip events under a variety of tectonic settings probably leading up to the current stress regime sustained during quaternary thus our results suggest that the newly identified fault could be a quaternary fault and hence it is necessary to perform more paleoseismic investigations around the study region this case study emphasizes the importance of the careful interpretation of tectonic landforms and fault zone structures in the study of active faults and proposes a suitable research procedure for the identification of active faults in korea

natural fractures in tight oil sandstones a case study of the upper triassic yanchang formation in the southwestern ordos basin china natural fractures are important storage spaces and fluid flow channels in tight oil sandstones intraformational open fractures are the major channels for fluid flow in tight oil sandstones small faults may provide fluid flow channels across different layers according to analogous outcrops cores and borehole image logs small faults and intraformational open fractures are developed in the tight oil sandstones of the upper triassic yanchang formation in the southwestern ordos basin china among them high dip angle intraformational open fractures are the most abundant northeast southwest trending fractures are the principal fractures for fluid flow because that is the present day maximum horizontal compressive stress direction combined with production data horizontal wells striking normal to or at a large angle relative to the major flow pathways are beneficial for tight oil production improvement fractures with high dip angles are the main factor that influences initial oil production linkage and tip damage zones are more favorable for oil production improvement than wall damage zones this study provides an example of natural fracture characterization and unravels fracture contributions to reservoir physical properties and oil production of tight oil sandstones which could provide a geological basis for oil exploration and development in tight sandstones

a model for the structure and development of fault zones cross sections of fault zones commonly show two sub parallel slip surfaces which bound more or less deformed rock this characteristic geometry can be explained by a combination of 9tip line9 and 9asperity9 bifurcation processes fault tip line bifurcation is due to irregular tip line propagation resulting in leading edge segmentation fault overlap and eventual duplex formation asperity bifurcation removes a fault surface irregularity by the generation of a new slip surface which by passes the original slip surface repetitions of either or both bifurcation processes give rise to a fault zone with a complex and unpredictable internal geometry these processes are described mainly on the basis of observation of normal faults hut can be applied to other fault types fault zone thickening by bifurcation is intermittent rather than progressive and localised fault zone thinning may occur

hydraulic characterization of a fault zone from fracture distribution abstract a quantitative assessment of how faults control the migration of geofluids is critical in many areas of geosciences we integrated geological fieldwork quantitative analysis of the fractures distribution and numerical modeling to build a geometrical representation of a fault zone and to characterize its hydraulic properties our target is a fault located in the majella mountain italy we collected 21 scan lines across the fault profile in order to characterize its architecture the numerical modeling of the fracture network of the damage zones and their hydraulic parameters was performed using both commercial move and open source software dfnworks and pflotran move was used to build a representative model of the fault zone using fracture spacing as a proxy and to model the hydraulic parameters of the different fault domains dfnworks and pflotran were employed to infer the hydraulic parameters of the damage zones of the fault and then upscale these properties to an equivalent continuum domain suitable for fluid flow simulations through the whole fault zone our findings show how even in a relatively small area it is possible to describe changes in terms of hydraulic properties of a fault zone and to build models capable to represent these variations

influence of p t conditions on the style of normal fault initiation and growth in limestones from the se basin france abstract a conventional and cathodoluminescence microscopy stable isotope and fluid inclusion study was undertaken on normal fault zones exposed on vertical cliffs in tithonian limestones of the french se basin the aim was to determine the chronology of deformation and factors controlling normal fault nucleation and evolution in carbonate rocks two models are proposed for fault zone development depending on the depths at which deformation takes place at depths of 3 3 5 km incipient shear zones consist of en echelon veins filled by fibrous calcite and confined to limestone layers bounded by thin clayey interlayers as deformation increases and the layers rotate slip occurs along the clay rich interlayers a system of pull aparts forms allowing displacement to increase pull aparts are commonly filled by fibrous calcite crystals at depths of 1 5 2 km faults initiate as small slip surfaces early nucleating in some limestone layers their propagation is impeded by thin clayey interlayers which enhances fracturing and bending of the limestone layers as slip surfaces propagate they overlap and can connect with one another by means of dilational jogs that are filled by large euhedral calcite crystals in the first case pull aparts are coupled with the solution seams that reuse preexisting rotated clay rich interlayers as they formed they progressively filled and the fluid circulation remained local in the second case longer slip planes connect by dilation jogs that are not immediately filled which enhance the circulation of fluids which show chemical variations it appears that p t conditions strongly control the relative role of brittle processes and solution crystallization mechanisms and the style of the early stages of normal faulting in the same limestone rocks

the depth dependence of heat production in the continental lithosphere derived from seismic velocities an experimentally established relationship enables the conversion of compressional seismic velocity to heat production a the conversion performed for 47 characteristic seismic sections from various tectonic units in central and eastern europe yields a general decrease of a with depth z the pattern of decrease depends on geological age young tectonic units with high heat flow exhibit a more rapid decrease the depth dependence of a does not follow the simple exponential law a z a o exp z d the logarithmic decrement d has the dimension length in general d decreases with depth from 20 30 km at 10 km depth to less than 10 km at the moho in the uppermost 10 km of the crust a certain redistribution of the heat producing radioelements u and th can occur by deep groundwater migration through microcrack networks below the moho heat production attains values which represent only insignificant contributions to heat flow through or to temperature field changes in the lithosphere

petroleum geology and potential hydrocarbon plays in the gulf of suez rift basin egypt the gulf of suez in egypt has a north northwest south southeast orientation and is located at the junction of the african and arabian plates where it separates the northeast african continent from the sinai peninsula it has excellent hydrocarbon potential with the prospective sedimentary basin area measuring approximately 19 000 km 2 and it is considered as the most prolific oil province rift basin in africa and the middle east this basin contains more than 80 oil fields with reserves ranging from 1350 to less than 1 million bbl in reservoirs of precambrian to quaternary age the lithostratigraphic units in the gulf of suez can be subdivided into three megasequences a prerift succession pre miocene or paleozoic eocene a synrift succession oligocene miocene and a postrift succession post miocene or pliocene holocene these units vary in lithology thickness areal distribution depositional environment and hydrocarbon importance geological and geophysical data show that the northern and central gulf of suez consist of several narrow elongated depositional troughs whereas the southern part is dominated by a tilt block terrane containing numerous offset linear highs major prerift and synrift source rocks have potential to yield oil and or gas and are mature enough in the deep kitchens to generate hydrocarbons geochemical parameters sterane distribution and biomarker correlations are consistent with oils generated from marine source rocks oils in the gulf of suez were sourced from potential source rock intervals in the prerift succession that are typically oil prone type i and in places oil and gas prone type ii or are composites of more than one type multiple types i ii or iii for oil prone oil and gas prone or gas prone respectively the reservoirs can be classified into prerift reservoirs such as the precambrian granitic rocks paleozoic cretaceous nubian sandstones upper cretaceous nezzazat sandstones and the fractured eocene thebes limestone and synrift reservoirs such the miocene sandstones and carbonates of the nukhul rudeis kareem and belayim formations and the sandstones of south gharib zeit and

extensional faults in fine grained carbonates analysis of fault core lithology and thickness displacement relationships abstract a study of 103 extensional faults hosted by fine grained carbonates in western sinai svalbard and oman reveals that faults vary geometrically between simple cores and cores comprising fault splays lenses segment linkages and overlap structures fault core rocks are typically carbonate breccias carbonate and shale gouge shale smear secondary calcite cement and veins and host rock lenses there is a significant scatter in the core thickness for any given displacement but the overall pattern is that the thickness increases with displacement this increase best fits a power law function 0 29d 0 56 that describes a gradual decrease in the thickness displacement relationship for increasing slip along faults in more detail the general function can be seen as the sum of two power law trend lines the first representing thin localized fault cores with generally simple and planar geometry the second representing thicker fault cores with complex geometry of lenses and overlap structures and with fault rock membranes the studied faults show a significant change in composition and geometry from small 0 1 m to moderate 1 10 m and to large offset faults 10 400 m the overall pattern is that fault initiates as fractures filled with calcite veins and thin shear fractures that hosts gouge membranes with increased fault offset complexity increases with breakdown of veins more extensive fault rock membranes and a trend towards development of lenses when offset exceeds 100 m cores become complex with multiple slip zones cemented breccia and shale smear membranes and various types of lenses we envision that the fault development as reflected by offset is dominated by forces extension compression acting in the fault mechanical heterogeneity of wall rocks the core lithologies and their developing rheology and especially geometric effects arising from fault irregularities

fault and fluid interaction in a rifted margin integrated study of calcite sealed fault related structures southern corinth margin this work integrates microstructural petrologic microthermometric and geochemical analysis of calcite sealed fault related structures of the major faults of the southern margin of the corinth rift greece it draws attention to the main deformational processes and fault fluid inter action in fault zones along the whole margin data analysed come from the compact breccia located immediately adjacent to major fault planes samples were collected at different positions alongside different faults juxtaposing synrift continental deposits hanging wall against the prerift pindus limestones footwall this implies hectometric fault displacements and that the fault zones have recorded a relatively long evolution of deformation our study identifies four main defor mation features common to all studied faults calcite cemented breccia extensional veins shear veins and fault slip surfaces the integrated data analysis shows that deformation structures and fault rocks that coexist in the same outcrop formed at different depths and times during inferred upward fault propagation the style of deformation evolved from distributed brecciation to loca lized slip surfaces and from a closed system with fluid rock equilibrium during brecciation to a more open one with limited influx of meteoric water during extensional and shear fracturing this implies relative uplift of the footwall during fault propagation and fault interaction with different water aquifers as the fault propagates upwards the results demonstrate similar fault evolution and fault fluid interaction through the entire rifted margin and during the whole rifting period

textural elemental and isotopic characteristics of pleistocene phreatic cave deposits jabal madar oman abstract two main types of karst formation are commonly known the surficial meteoric one and the subsurface hypogenic karst which can be related to both carbonic h2co3 and sulfuric h2s acids this paper documents evidence for a third co2 regime related type of karst that is less commonly described petrographic and geochemical properties of exhumed pleistocene phreatic cave deposits from the diapiric jabal madar dome in northern oman are documented and discussed in a process oriented context these calcites form at the interface between two fundamentally different diagenetic and hydrogeological domains the deep seated hydrothermal and the near surficial meteoric vadose one four calcite phases are recognized i acicular ii blocky to stubby elongated iii proto palisade and iv macro columnar calcites the macro columnar calcites forming the last stage of precipitation are conspicuous due to their cyclical red zonation and they form the main geochemical focus of this study fluid inclusion data point to fluid temperatures of between 30 to 50 c monophase liquid inclusions and elevated salinities 1 6 to 7 3 wt nacl equivalent low carbon isotope data 8 to 9 are in agreement with the influx of soil zone co2 whereas decreasing 18o 15 values might point to mixing of saline hydrothermal and 18o depleted meteoric freshwater i e two fluid sources trace element and stable isotope data shift between the different cement phases and vary cyclically across the red zoning in macro columnar calcites with respect to the intra crystal variability these patterns are perhaps best explained in the context of redox potential two interpretations are presented the one favored here suggests that the cyclical red zoning in macro columnar calcites is controlled by pleistocene monsoonal climate patterns

reactivation history of the long lived billefjorden fault zone in north central spitsbergen svalbard new geological mapping has revealed further details of the tectonic and stratigraphic effects of devonian and later reactivations of the billefjorden fault zone one of a number of important north south trending lineaments in svalbard analysis of offsets along the many steeply dipping faults within the zone and effects on the subsidence and deformation of the adjacent crustal blocks is presented as a series of tectonic maps from the late devonian through to the tertiary late devonian sinistral transpression suggested previously cannot be ruled out and carboniferous reactivation was dominated by extension with possibly a slight dextral strike slip component after late carboniferous to early cretaceous platform subsidence during which the fault zone had little effect on sedimentation development of the tertiary west spitsbergen fold belt related to the opening of the arctic ocean involved compressive and transpressive reactivation of basement seated structures further east including the billefjorden fault zone in the billefjorden austfjorden area this produced a large monoclinal fold across the fault zone which was later cross cut by extensional structures to produce the present day billefjorden syncline this localized late extension is related to a slight variation in the trend of the billefjorden fault zone through this area

constraining the timing of brittle deformation and faulting in the toki granite central japan abstract constraining of the timing of fault zone formation is of fundamental geotectonic importance to understand structural evolution and brittle fault processes here we present authigenic illite k ar age data from brittle fault zones comprising two gouges within the toki granite central japan the gouge samples were collected at depths of 252 9 and 403 7 m from a shaft at the mizunami underground research laboratory and were separated into five grain size fractions

fault deformation mechanisms and fault rocks in micritic limestones examples from corinth rift normal faults abstract a multidisciplinary study investigates the influence of different parameters on fault rock architecture development along normal faults affecting non porous carbonates of the corinth rift southern margin here some fault systems cut the same carbonate unit pindus and the gradual and fast uplift since the initiation of the rift led to the exhumation of deep parts of the older faults this exceptional context allows superficial active fault zones and old exhumed fault zones to be compared our approach includes field studies micro structural optical microscope and cathodoluminescence geochemical analyses 13 c 18 o trace elements and fluid inclusions microthermometry of calcite sin kinematic cements our main results in a depth window ranging from 0 m to about 2500 m are i all cements precipitated from meteoric fluids in a close or open circulation system depending on depth ii depth in terms of p t condition determines the development of some structures and their sealing iii lithology marly levels influences the type of structures and its cohesive non cohesive nature iv early distributed rather than final total displacement along the main fault plane is the responsible for the fault zone architecture v petrophysical properties of each fault zone depend on the variable combination of these factors

evolution of fracture and fault controlled fluid pathways in carbonates of the albanides fold thrust belt the process of fracture and fault formation in carbonates of the albanides fold thrust belt has been systematically documented using hierarchical development of structural elements from hand sample outcrop and geologic map scales the function of fractures and faults in fluid migration was elucidated using calcite cement and bitumen in these structures as a paleoflow indicator two prefolding pressure solution and vein assemblages were identified an overburden assemblage and a remote tectonic stress assemblage sheared layer parallel pressure solution surfaces of the overburden assemblage define mechanical layers shearing of mechanical layers associated with folding resulted in the formation of a series of folding assemblage fractures at different orientations depending on the slip direction of individual mechanical layers prefolding and folding related fracture assemblages together formed fragmentation zones in mechanical layers and are the sites of incipient fault localization further deformation along these sites was accommodated by rotation and translation of fragmented rock which formed breccia and facilitated fault offset across multiple mechanical layers strike slip faults formed by this process are organized in two sets in an apparent conjugate pattern calcite cement and bitumen that accumulated along fractures and faults are evidence of localized fluid flow along fault zones by systematic identification of fractures and faults their evolution and their fluid and bitumen contents along with subsurface core and well log data we identify northeast southwest trending strike slip faults and the associated structures as dominant fluid pathways in the albanides fold thrust belt

extensional fault cores in micritic carbonate case studies from the gulf of corinth greece abstract the major pisia and doumena faults of the corinth rift greece are both hosted by micritic carbonate rock their common fault elements are principal slip surfaces layers of fault rocks fault rock and host rock lenses corrugations and smaller shear and tension fractures along planar fault segments a corrugated slip surface with an associated thin fault rock layer is formed well developed down dip corrugations indicate movement along the same surface over many fault increments bends jogs in the faults are sites of complex structural relations hosting frequent lenses more porous fault rocks and dense networks of fractures major jogs in the slip surfaces have both strike and dip oriented undulating curvature that are associated with higher order fracture networks as well as frequent lenses fault core lens shapes of the doumena fault show relationship of length vs width of 3 2 similarly principal slip surfaces of the two faults show undulations with aspect ratios of amplitude vs wavelength 1 19 and 1 14 in strike direction despite a prominent difference in down dip geometry the intrinsic deformation in fault cores of micritic carbonate supports a model in which fluids entered the core by damage zone fractures that are linked to the principal slip surface flow along the fault core was controlled by the fracture system of lenses and thereby lens connectivity but may have been hampered by flow retarding fault rocks the flow potential is especially well developed in fault bends and breached relays due to frequent lenses and well developed fracture networks