identification of permian palaeowind direction from wave dominated lacustrine sediments lodeve basin france lacustrine environments are an excellent indicator of continental palaeoclimate in particular the sedimentary record of waves in lakes may be used to constrain atmospheric palaeocirculation wave ripples have been identified in a permian lacustrine basin the salagou formation 260 250 ma lodeve basin located in the southern french massif central part of the western european hercynian mountain chain wave ripple patterns are interpreted with regards to hydrodynamics and water palaeodepth it is shown that in the case of the salagou formation wave ripple orientations were controlled by the direction of the prevailing palaeowind the late permian wind blew from between north and 20 east of north possibly over several millions of years and certainly throughout the period of deposition of about 2000 m of strata in the lodeve basin permian lacustrine sedimentation is widespread and well preserved on the earth s surface and so wave ripple data may help constrain numerical modelling of the earth s past climates especially with regards to permian times outside of desert regions

horizontal lamination and the sequence of bed phases and stratification under upper flow regime conditions two forms of horizontal laminae have been produced under upper flow regime conditions in a flume by deposition on a plane bed and on low in phase waves upper plane bed laminae consist of approximately equal numbers of fining upward fu and coarsening upward cu textural laminae heavy minerals when present are typically within or form cu laminae in horizontal laminae formed under low in phase waves fu laminae may predominate and are significantly thicker than cu laminae heavy minerals are associated with the tops of some fu laminae and are absent from cu laminae deposits aggraded on plane beds and low in phase waves both display low angle 13 14 upstream grain imbrication upper plane bed horizontal laminae are attributed to the effects of the burst sweep cycle on local bedload transport bursts form fu laminae and sweeps form cu laminae some fu laminae in in phase wave deposits are thought to form with downstream migration of bed waves on which sand size decreases from trough to crest heavy minerals are concentrated in the tops of these fu laminae due to their enrichment on the crests of the migrating bed waves other fu and cu laminae in in phase wave deposits probably formed by the action of bursts and sweeps as on upper plane beds a sequence of bed phases and stratification formed under upper flow regime conditions is described based on the observations here combined with descriptions from the literature with increasing flow strength the gradual sequence of bed phases is 1 plane bed 2 low relief downstream migrating inphase waves increasing in amplitude and wavelength with increasing flow strength 3 stationary in phase waves 4 upstream migrating including breaking wave antidunes the sequence of stratification formed under these bed phases is 1 upper plane bed horizontal lamination 2 in phase wave horizontal lamination to in phase wave foreset cross laminae 3 in phase wave drape laminae 4 antidune backset cross laminae

permian dune patterns in northwestern europe challenged abstract permian desert dunes in northwestern europe previously thought to exhibit a transverse pattern are herein reinterpreted as oblique evidence includes a a light cluster of foreset dip directions b cross bed dip angles of 15 to 28 c concave upward curvature of bed profiles d sweeping bundles of thin laminae generated by ripple migration with minor grainfall influence at the bottom and increasingly thicker laminae with a greater grainfall influence upflank straight crested alongslope trending ripples are commonly present e grain population better or equally sorted upflank in sharp contrast with slipface sands which are more symmetrically skewed and better sorted downslope the cases examined are from the isle of arran the english midlands the north sea and the german basins interpretation of the dunes as oblique rather than transverse implies that in most cases the prevailing winds were northerly and not northeasterly and easterly

interaction between aeolian fluvial and playa environments in the permian upper rotliegend group uk southern north sea the permian upper rotliegend group in offshore uk quadrants 42 43 47 and 48 comprises a sequence of mixed aeolian fluvial playa deposits these deposits are up to 300 m thick and contain a record of the interaction between desert fluvial systems and adjacent aeolian and playa environments the relative dominance of water vs wind transport and deposition in this stratigraphic package was a function of fluctuations in the discharge of ephemeral fluvial systems and changes in water table playa level driven by a combination of climatic change and syndepositional tectonics the rotliegend sedimentary record is punctuated by numerous surfaces recording erosion by wind and water the origin of these surfaces is mostly climatic with periods of increased runoff resulting in fluvial incision especially near active faults during periods of reduced runoff wind erosion of fluvial deposits occurred with fluvially derived sand being reworked into expanding aeolian dune fields wind erosion also occurred as a rising water table isolated dunes from their sediment supply resulting in deflation of dunes down to the water table these surfaces formed in a basin that was subsiding thus even in a background of overall increasing accommodation space climatically driven falls in the water table allowed for periods of erosion the occurrence of significant erosion especially near syndepositional fault zones resulted in a sedimentary record that shows pronounced lateral as well as vertical facies variations

shelf construction in a foreland basin storm beds shelf sandbodies and shelf slope depositional sequences in the upper cretaceous mesaverde group book cliffs utah the upper cretaceous campanian kenilworth member of the blackhawk formation mesaverde group is part of a series of strand plain sandstones that intertongue with and overstep the shelfal shales of the western interior basin of north america analysis of this section at a combination of small sedimentological and large stratigraphical scales reveals the dynamics of progradation of a shelf slope sequence into a subsiding foreland basin four major lithofacies are present in the upper mancos and kenilworth beds of the book cliffs a lag sandstone and channel fill shale lithofacies constitutes the thin basal transgressive sequence which rests on a marine erosion surface it was deposited in an outer shelf environment shale interbedded sandstone and shale and amalgamated sandstone lithofacies were deposited over the transgressive lag sandstone lithofacies as a wave dominated delta and its flanking strand plains prograded seaward analysis of grain size and primary structures in kenilworth beds indicates that there are four basic strata types which combine to build the observed lithofacies the fine to very fine grained graded strata of the interbedded facies are tempestites deposited out of suspension by alongshelf storm flows geostrophic flows there is no need to call on cross shelf turbidity currents density underflows to explain their presence very fine to fine grained hummocky strata are likewise suspension deposits created by waning storm flows but were deposited under conditions of more intense wave agitation on the middle shoreface cross strata sets in this region are bed load deposits that accumulated on the upper shore face in the surf zone lag strata are multi event bed load deposits that are the product of prolonged storm winnowing they occur on transgressive surfaces while the graded beds are tempestites in the strict sense all four classes of strata are storm deposits the distribution of strata types and their palaeocurrent orientations suggests a model of the kenilworth transport system driven by downwelling coastal storm flows and probably by a northeasterly alongshore pressure gradient the stratification patterns shift systematically from upper shoreface to lower shoreface and inner shelf lithofacies partly because of a reduction in fluid power expenditure with increasing water depth but also because of progressive sorting which resulted in a decrease in grain size in the sediment load delivered to successive downstream environments the kenilworth member and an isolated outlier the hatch mesa lentil constitute a delta prodelta shelf depositional system their rhythmically bedded lenticular sandstone and shale successions are a prodelta shelf facies and may be prodelta plume deposits major upper cretaceous sandstone tongues in the book cliffs are underlain by erosional surfaces like that beneath the blackhawk formation which extend for many tens of kilometres into the mancos shale these surfaces are the boundaries of upper cretaceous depositional sequences the sequences are large scale genetic stratigraphic units they result from the arranging of facies into depositional systems the depositional systems are in turn stacked in repeating arrays which constitute the depositional sequences the anatomy of these foreland basin sequences differs

sole marks in storm event beds in the permo carboniferous talchir formation raniganj basin india abstract sole marks in storm event beds are described for the first time from talchir formation permo carboniferous of raniganj basin india gutters and grooves trending subparallel to wave ripple crests were formed by shore parallel geostrophic flow at the initial phase of storms during intensification of storms oscillation dominated shore normal current produced gutters grooves and bipolar bimodal prod marks and bounce marks at nearly perpendicular or highly oblique to the axis of major wave ripple crests superposition of shore normal oscillatory flow on shore parallel geostrophic current during peak storms is evident from curvilinear crosscutting and turnabout groove marks hydrodynamic interpretation of these sole marks interrelationship between palaeogeographic constraints governing the overall sediment dispersal pattern and the stratification architecture in storm event beds signify complex interplay of mutually perpendicular shore parallel and shore normal components of storm current in shallow marine setting

depositional controls on reservoir properties in a braid delta sandstone tirrawarra oil field south australia the tirrawarra sandstone contains 146 million bbl of oil in tirrawarra field in the cooper basin of south australia we used core well logs and petrophysical data to construct a depositional facies based flow unit model of the reservoir which describes rock properties and hydrocarbon saturations in three dimensions using the model to calculate volumes and residency of original and remaining oil in place we identified an additional 36 million bbl of oil in place and improved understanding of past production patterns the tirrawarra sandstone reservoir was deposited in a carboniferous permian proglacial intracratonic setting and is composed of lacustrine and fluvial facies assemblages the stratigraphic framework of these nonmarine facies is defined by distinctive stacking patterns and erosional unconformities mudstone dominated zones that are analogous to marine maximum flooding surfaces bound the reservoir at its base a progradational lacustrine delta system composed of lenticular mud clast rich sandstones enclosed in mudstone is truncated by an unconformity sandstones in these lower deltaic facies lost most of their porosity by mechanical compaction of ductile grains above the unconformity a braid delta system dominated by aggradational bed load channel fill sandstones forms the core of he reservoir sediment reworking by channel migration and locally by shore zone processes created quartz rich multilateral sandstones which retained the highest porosity and permeability of all the reservoir facies and contained most of the original oil in place the braid delta is erosionally truncated and overlain by a more proximal braid plain system braided channel sandstones however are overlain by lenticular meandering channel sandstones which in turn grade upward into widespread mudstones and coals thus this uppermost part of the reservoir displays a retrogradational stacking pattern and upward decreasing reservoir quality on the basis of the systematic arrangement of facies within this stratigraphic framework as well as facies related differences in composition and texture we identified reservoir flow units that have characteristic petrophysical properties our results demonstrate that depositional variables are the primary controls on reservoir quality and productivity in the tirrawarra sandstone

shelf storm flow dynamics insight from the mesoproterozoic rampur shale central india abstract the intracratonic rift related mesoproterozoic rampur shale in kudri india formed in the marine mid and outer shelf domain it bears a dominant imprint of shore parallel storm driven flow as predicted by oceanographers for modern shelves and thus differs from other ancient storm deposits in the geological record in the rampur shale gutters are shore parallel while tool marks of various kinds are both shore parallel and shore normal and show bipolarity in both directions hydrodynamic analysis and inter relationships between the flow features suggest that the storm driven flow was shore parallel dominantly unidirectional and steady initially and that it became increasingly unsteady thereafter while also becoming dominantly shore normal during peak oscillation as storm conditions waned the gutters were filled by sediments under dominant wave influence these rampur data are consistent with observations made in modern seas and suggest that storm driven flows in general have evolved in the same way over time although their geological records may vary in details because of local constraints

oligocene storm induced lacustrine deposits in the yaxi area of the jiuxi basin northeastern margin of the tibetan plateau abstract storm induced deposits in the sedimentary record can now be easily identified on account of a better understanding of processes of unidirectional and oscillatory flow thin bedded sandstone siltstone and interlayered mudstone deposits of the oligocene jianquanzi member in the yaxi area of the jiuxi basin along the northeastern margin of the tibetan plateau were formed by shallow lacustrine storm generated flows petrologic analysis reveals that the sandstones exhibit moderate to high compositional maturity but are texturally sub mature to immature based on investigation of drill cores six storm deposit lithofacies are identified including massive or graded sandstone parallel and trough cross bedded sandstones hummocky cross stratified sandstone wave rippled sandstone and siltstone massive or horizontal bedded mudstone and structurally deformed sandstone and mudstone in a vertical succession these lithofacies occur as three fining upward lithofacies associations each of which represents different architectural elements and depositional processes of proximal to distal storm deposits the relatively coarse proximal architectural element is formed by strong density flows and unidirectional dominated combined flows the transitional architectural element is dominated by unidirectional and oscillatory dominated combined flows to pure oscillatory flows resembling tb e divisions of the classic bouma sequence the relatively fine distal architectural element is dominated by unidirectional dominated combined flows with a very weak oscillatory flow component the origin of storms responsible for these deposits is attributed to asian winter monsoons associated with the paleoclimatic and paleogeographic setting

some guidelines in reconstructing ancient sea conditions from wave ripplemarks abstract the collection of substantial field data on wave ripple mark spacing wavelength steepness grain size and symmetry index from the miocene burdigalian sandstones of western switzerland has allowed apparently close reconstruction of sea conditions results indicate however that ancient wave reconstructions must be restricted at present to data from relatively steep ripple marks vfi less than 7 5 i e vortex ripples data from the flatter ripple marks post vortex types formed at high oscillatory shear stresses do not provide reasonable estimates of wave conditions penecontemporaneous overwashing and or post depositional compaction ripple formation near the destruction condition rather than the threshold of sediment movement orbital diameters far exceeding ripple spacing and superimposed unidirectional currents are all factors which seriously affect wave reconstructions evaluation of ancient wave conditions provides insight into geologically important phenomena such as local water depth and basin size

the morphology of permian palaeodunes a reinterpretation of the bridgnorth sandstone around bridgnorth england in the light of modern dune studies abstract an examination of the permian bridgnorth sandstone formation around bridgnorth shropshire has indicated that it probably accumulated in a combination of transverse and barchanoid draas with superimposed oblique crescentic and linear dunes under the influence of a fluctuating wind regime three major recurrent facies associations were identifiable isolated transverse draa with superimposed oblique crescentic and linear dunes barchanoid draa with superimposed oblique crescentic and linear dunes and bimodal sand sheets with isolated dome dunes the overall long term wind direction was probably from the east and appears to have controlled draa orientation the orientations of the superimposed dunes however were probably related to medium term wind fluctuations from a more northerly quarter possibly modified by the draa bedforms short term wind reversals may have reworked slipfaces as shown by the presence of internal scour surfaces within dune and draa foresets

chronostratigraphy and paleoclimatology of the lodeve basin france evidence for a pan tropical aridification event across the carboniferous permian boundary abstract paleosols preserved within the carboniferous permian succession of the lodeve basin massif central france change stratigraphically from histosols to calcic vertisols and calcisols to gypsic vertisols and ultimately back to calcic vertisols and calcisols new high precision u pb zircon ages ca idtims for tuff beds within the lodeve and adjacent graissessac basins significantly revise the chronostratigraphy of these and correlated permian terrestrial basins of eastern euramerica under the newly revised chronostratigraphy presented here these stratigraphic changes in morphology indicate a substantial drying of paleoenvironments across the carboniferous permian boundary with a trend toward progressively more arid and seasonal climates through most of the early permian this newly realized chronology provides a paleoenvironmental and paleoclimatic timeline for eastern tropical pangea that is contemporaneous with similar records in western pangea and suggests pan tropical progressive climate change toward aridity and seasonality occurred from the late carboniferous through early permian

late orogenic extension in mountain belts insights from the basin and range and the late paleozoic variscan belt from two examples of orogenic domains some general mechanisms significant of late orogenic tectonic processes in mountain belts are characterized the basin and range province and the variscan belt in the french massif central have both suffered important compressional orogenic crustal thickening and the results of late orogenic processes can be observed in the field both areas are covered by deep seismic profiling providing constraints on the geometry of a crust which has been restored to a normal thickness late orogenic features from the two domains are compared at different scales and their tectonic significance for extension mechanisms is discussed at the scale of the orogenic domains the most prominent tectonic features are the metamorphic core complexes mcc which expose deformed rocks from the middle crust generally affected by high temperature low to medium pressure metamorphism partial melting and widespread granite emplacement in these mcc large scale extensional shear zones present an intense mylonitic deformation characterized by low dipping foliations and pervasive stretching lineations they show a complete evolution from early deep seated ductile deformation generally achieved under high temperature low to medium pressure metamorphism to a late shallow brittle stage characterized by cataclastic deformation the late detachment stage generally controls the development of asymmetrical extensional sedimentary basins filled by continental deposits two main geometries of mcc are defined that are characterized by differing geometry and kinematics of low angle shear zones in the first case two low angle shear zones with opposite vergence develop along the flanks of a roughly symmetrical mcc often one system is dominant over the other the second geometry characterizes asymmetrical mcc bounded by a single normal shear zone which is upwarped during uplift and doming of the core caused by tectonic denudation detailed strain analysis performed in several extensional shear zones shows that the deformation regime is heterogeneous and results from general noncoaxial flow deformation along the shear zones evolves progressively from slight homogeneous pure shear strain to intense heterogeneous noncoaxial shear strain strain distribution within the lower crust is less well constrained by field observation however analogies between cocorp and ecors deep seismic reflection profiles give important constraints on crustal structure wide zones of highly subhorizontally layered lower crust and a flat high amplitude reflection moho characterize both evolved orogenic domains suggesting that major deformations and flow occur within the lower crust during extension a kinematic model involving heterogeneous crustal deformation and regional scale flow fits relatively well with late orogenic structures observed in continental domains a weak hot upper mantle allows large scale flow of lower crust material from zones of deep ductile extension to uplifted domains of upper crustal denudation heterogeneous strain is accommodated by low angle extensional shear zones from localized zones of extension in the brittle crust to ductile lower crust combined pure and simple shear occurs along localized shear zones whereas at the scale of the whole lithosphere deformation nearly corresponds to a vertical pure shear such deformation processes which affect a thick and hot crust seem to be common in both compared domains suggesting that late orogenic extensional processes are slightly dependent of the type of contractional tectonics thus as much in the andean type west american cordilleran belt as in the collision type variscan belt late orogenic processes produced similar extensional features

the late permian climate what can be inferred from climate modelling concerning pangea scenarios and hercynian range altitude abstract a major unsolved geodynamic problem is the permian pangea plate configuration at the end of paleozoic era around 255 ma while consensual geology indicates a plate arrangement close to that of the jurassic prior to the atlantic opening pangea a paleomagnetic data indicates a nearly 3000 km more eastward position of gondwana with respect to laurussia leading to major plate and relieves reorganisation during permo triassic times pangea b using an atmospheric general circulation model agcm we simulate the climatic response to both configurations we also test the fundamental role of paleo elevations through sensitivity experiments each simulated climate is then compared with the aim of constraining the best fit to a particular paleogeographic scenario main trends of simulated late permian climate in agreement with paleoclimatic indicators are 1 a warm temperate climate accompanied by a monsoon circulation over the eastern side of gondwana 2 a cold temperate climate marked by strong annual thermal amplitude at high latitudes in gondwana and in siberia 3 an arid belt in the subtropics over the western side of gondwana and laurussia and 4 strong climatic differences over both hemispheres respectively main variance is found over laurussia with a simulated tropical climate while an arid climate is suggested by paleodata simulating different paleo elevations of the appalachian and the variscan fold belts can solve this discrepancy the best model data fit is reached for a mean altitude of 4500 m in the appalachians and appears to be dependent of pangea configuration with a southern europe variscan range of some 3000 m in a pangea a configuration or only 2000 m in for pangea b taking into account the geodynamic context we argue that pangea b appears to be the more probable configuration

ripple marks in quartz arenites of the hurwitz group northwest territories canada evidence for sedimentation in a vast early proterozoic shallow fresh water lake abstract supermature quartz arenites of the whiterock member deposited in the early proterozoic intracratonic hurwitz basin have a maximum thickness of 400 m and a minimum areal extent of 100 000 km2 the unit is unusual in that it is virtually devoid of other rock types and displays sedimentary structures that consist almost entirely of short spaced ripple marks and parallel stratification both formed by oscillatory flow the ripples have spacings that are consistently small average

record of tide wave influence on the coal bearing permian barakar formation raniganj basin india abstract the coal bearing barakar formation early permian of the raniganj gondwana basin was previously interpreted as continental fluvial sediments with little evidence for tide wave influences the present contribution details the sedimentary attributes of marginal marine tidal and wave activities preserved within an overall braided meandering fluvial depositional setting from the barakar formation tide dominated sedimentary features include i tidal bundle sequences showing sandstone foresets with mud drapes ii periodic variation in foreset thickness iii lateral and vertical accretion of cross strata bundles with a downcurrent change to sigmoidal cross strata iv mutually opposite cross strata sets separated by sub horizontal plane laminated sandstone mudstone and v alternate sand and mud dominated rhythmites draping of the tidal stratifications by wavy laminated muddy siltstone suggests immediate invasion by low energy silt mud depositing waves that helped preserve the tidal features during subsequent reworking open marine storm wave activities are evident from hummocky cross stratification and various types of wave ripples preserved separately within coarse to fine grained sandstone in the middle upper part of the succession recognition of tide storm influenced marine sedimentation significantly changes the existing paleogeographic model to a fluvial estuarine depositional environment

exploratory flow duct experiments on combined flow bed configurations and some implications for interpreting storm event stratification abstract experiments were conducted to define equilibrium combined flow bed configurations developed under a wide range of oscillatory uo and unidirectional uu velocity components with a constant oscillation period of 8 5 sec and median grain size of 0 09 mm in the range of flows studied uo 0 0 80 m sec uu 0 0 25 m sec the bed phases are no movement small 2d ripples small 3d ripples large 3d ripples and plane bed small 2d ripples are stable at low uo and uu by increasing either velocity component the plan view bed configuration becomes progressively less regular as small 3d ripples develop small 3d ripples are stable at low to moderate uo and a wide r nge of uu under purely oscillatory flow as uo increases beyond about 0 40 m sec large scale hummocky bed forms become stable when a unidirectional component is applied these bed forms quickly develop a downstream asymmetry and generally move in the direction of uu the dip angles of the lee flanks increase with increasing uu although they remain less than the angle of repose at high oscillatory velocities uo 0 70 0 80 m sec plane bed is the stable bed phase when uu 0 05 m sec much hummocky cross stratification shows a preferred dip direction of the coset laminae our experiments support the idea that such cross stratification is produced by combined flow the large 3d ripples produced at high oscillatory velocities and small to moderate unidirectional velocities would presumably generate what might be called anisotropic hummocky cross stratification if we had been able to aggrade the bed during the runs this would be the case even in dominantly oscillatory flow the experiments show that even a weak unidirectional current of several centimeters per second superimposed upon a strong oscillatory flow results in bed forms that move predominantly in a single direction and that leave sets of laminae that dip predominantly in that direction in runs at large uo the purely oscillatory large scale bed forms were quickly planed off as uu was increased from zero but a series of almost stationary gentle undulations on the bed surface persisted for indefinitely long times where the original topographic highs were situated even at the highest unidirectional flow investigated 0 25 m sec this suggests a possible origin for the gentle undulation observed in cretaceous parallel laminated shallow marine sandstones described by arnott 1987 1988 with spacings up to a few meters and heights not much more than a centimeter

lacustrine environment during lower beaufort upper permian karoo deposition in northern malawi abstract this paper provides the first detailed sedimentological facies analyses of a lower beaufort upper permian gondwana sequence from mt chombe are in northern malawi approximately 300 m of undeformed non marine mudstones siltstones and sandstones are preserved in isolated grabens exposed along the mzuzu karonga highway where it crosses the lake malawi escarpment five lithofacies are distinguished a finely laminated paper shales and muddy siltstones deposited in lakes with anoxic bottom waters b massive muddy siltstones and siltstones deposited in oxic lake waters c thinly bedded horizontally stratified siltstones from episodic sheet flows into a lake d cross stratified and flaser bedded siltstones and sandstones of higher energy lake environments and e massive and cross bedded coarse grained sandstones with small channels and intraformational pebble layers interpreted as marginal lacustrine deposits new dates by pollen indicate an uppermost permian interval the whole sequence appears to have been deposited in a large shallow lake complex as none of the strata displays subaerial features such as desiccation cracks pedogenesis or rootlets all facies are reworked as is also suggested by the lack of in situ faunal or floral remains organic matter is mainly land derived although some algal dominated intervals occur clastic mineralogy is immature uniform and dominated by feldspar and quartz clay minerals include smectite kaolinite and illite carbonate contents greater than 5 and up to 40 are taken as an evidence of periods of authigenic precipitation in a freshwater lake setting the mt chombe sequence is lithologically similar but differs in significant sedimentology aspects from equivalent sequences in the adjacent luwanga and ruhuhu basins where sub aerial deposition has been reported although all three basins are part of a stable cratonic palaeoenvironment the absence of the lower permian upper coal measures from karoo sequences in northern malawi is taken as evidence of some syndepositional topographic relief in the region

combined flow generation of sole structures including recurved groove casts associated with lower carboniferous lacustrine storm deposits in nova scotia canada abstract sole structures are common on bases of sandstone beds in lacustrine shoreline deposits of the horton bluff formation lower carboniferous nova scotia the structures include recurved groove casts the first reported occurrence other curvilinear grooves and opposed prod casts gutter casts and sinusoid like chevron marks are associated with these sole marks but flute casts and other undisputed indicators of unidirectional flow were not noted sole structures and gutter casts are oriented normal to the strike of wave ripple crests and to the elongation direction of hummocky cross stratified lenses inclined strata within the lenses locally show a preferred migration direction parallel to the elongation direction the erosional structures are inferred to have been generated during torms in a shallow lake by oscillatory and or combined flow the latter possibly associated with longshore currents these storms also produced hummocky cross stratification wave formed sole structures may be common in the rock record and can be recognized by curvilinear shapes including rare recurved shapes and bimodal orientations care should be taken when interpreting sole structures from wave influenced settings because they may not indicate directions of net sediment transport or the orientation of unidirectional currents

effect of velocity hiatuses in oscillatory flow on migration and geometry of ripples wave flume experiments a series of wave flume experiments was conducted to closely look at characteristics of geometry and migration of wave generated ripples with particular reference to the effect of velocity hiatuses during which the near bed flow velocity becomes much smaller than the threshold of sediment movement three types of wave patterns were generated two types for simulating waves with intervening velocity hiatuses and regular waves for comparison purposes in the former two types two different wavelengths of water waves were generated alternately in the course of a wave test the wave with a longer wavelength was set large enough to mobilize the bottom sediment whereas the wave with a shorter wavelength was set too small to mobilize the sediment the former two types were designed to be different in sequence of convexity and concavity of wave patterns the sequence with the convex concave longer wave and successive convex concave shorter wave was described as a zero up crossing wave pattern and the inverse sequence was described as a zero down crossing wave pattern the ripples developed under oscillatory flow with intervening hiatuses manifested the following characteristics in geometry and migration i the morphological characteristics of ripples namely wavelength height and the ripple steepness are unaffected by the intervening hiatuses of velocity ii the directions of ripple migration under the zero up crossing and zero down crossing wave patterns corresponded well with the directions of the flow immediately before onset of the hiatuses iii the observation of sand particle movement on the ripple surface indicated that under the zero up crossing waves the velocity hiatus prevents the entrained sediment cloud from being thrown onshore and thus the sediment grains thrown onshore are fewer than those thrown offshore as a result of the sediment movement over one wave cycle the net sediment transport is directed offshore under the zero up crossing wave pattern iv the velocity of ripple migration was highly correlated with acceleration skewness under most of the zero up crossing zero down crossing wave patterns flow acceleration skewed negative positive and ripples migrated offshore onshore

halite karst geohazards natural and man made in the united kingdom in the united kingdom permian and triassic halite rock salt deposits have been affected by natural and artificial dissolution producing karstic landforms and subsidence brine springs from the triassic salt have been exploited since roman times or possibly earlier indicating prolonged natural dissolution medieval salt extraction in england is indicated by the names of places ending in wich indicating brine spring exploitation at northwich middlewich nantwich and droitwich later victorian brine extraction in these areas accentuated salt karst development causing severe subsidence problems which remain a legacy the salt was also mined but the mines flooded and consequent brine extraction caused the workings to collapse resulting in catastrophic surface subsidence legislation was enacted to pay for the damage and a levy is still charged for salt extraction some salt mines are still collapsing and the re establishment of the post brine extraction hydrogeological regimes means that salt springs may again flow causing further dissolution and potential collapse

collapse of a hercynian tibetan plateau into a late palaeozoic european basin and range province the large width the importance of crustal shortening and the likelihood of thick crust in the late palaeozoic hercynian or variscan belt of southern europe suggest a tectonic evolution analogous to the evolution of the tibetan plateau and its neighbouring himalaya1 and of the altiplano and other high plateaux of the andes here we extend dewey and burke s analogy1 of the hercynian chain with tibet to include the subsequent stage of pervasive normal faulting and crustal extension and thinning which characterize the active tectonics of tibet parts of the high andes and the basin and range province of western north america it appears that normal faulting and rifting also characterize the late palaeozoic tectonic activity of the hercynian chain

sedimentary characteristics of thick layer lacustrine beach bars in the cenozoic banqiao sag of the bohai bay basin east china abstract lacustrine beach bar reservoirs have become important exploration targets in the bohai bay basin in china especially in the banqiao sag within the huanghua depression where some typical thick layer beach bar reservoirs have been discovered recently the average single layer thickness of the beach bar sand bodies in the second member of the paleogene shahejie formation within the sag is greater than 10 m and the cumulative thickness of these sands reach up to 100 m the second member of the shahejie formation in the banqiao sag consists of a third order sequence of three systems tracts a lowstand systems tract a transgressive systems tract and a highstand systems tract beach bar sand bodies were deposited widely in the sag in the lowstand systems tract but were less deposited in the other systems tracts the sedimentary characteristics distribution patterns and formation mechanisms of the beach bar sand bodies in the lowstand systems tract of the second member of the shahejie formation were systemically studied using cores wireline logs and 3d seismic data the beach bar was divided into five sedimentary microfacies namely sandy bar centre sandy bar flank interbar deposit coastal beach and infralittoral beach based on the integrated analysis of the paleostructure and sedimentary environment it was inferred that the thick layer beach bars in this area resulted from the combination and joint control of the sediment source system hydrodynamic environment lake level variations and contemporaneous fault activity firstly the sands in the braided river delta of the beidagang buried hill structural belt served as the provenance that provided the material basis for the beach bars in the banqiao sag secondly the wave effects in the gentle slope belt controlled the scale and distribution of the beach bars under the control of waves various sedimentary microfacies were regularly distributed in particular the continuous activity of the contemporaneous dazhangtuo fault contributed to the formation of the thick layer beach bars in the banqiao sag the contemporaneous fault controlled the allocation of the sediments providing abundant sands in the downthrown side of the fault in addition there was a constant high energy hydrodynamic environment near the fault plane where the sand bodies experienced long term reworking by waves and gradually formed beach bars with large thickness the activity of the contemporaneous fault increased the accommodation space in the lowstand systems tract of the second member of the shahejie formation which resulted in continuous sand deposition and provided the necessary conditions for forming the thick layer beach bars

is there evidence for geostrophic currents preserved in the sedimentary record of inner to middle shelf deposits abstract unidirectional oscillatory and combined flow paleocurrent data from many ancient wave dominated coastlines indicate that sediment transport was directed offshore at angles of 70 to 90 from the inferred local paleoshoreline solemarks and parting lineations from turbidite like storm beds and solemarks from hummocky beds indicate that flows transporting sediment offshore were orthogonal to the local shoreline the shore normal orientations of solemarks parting lineation and asymmetric ripples on hummocky cross stratification and their orthogonal relationship with respect to wave ripple crest orientation indicate that the dominant direction of wave approach at the sediment water interface was also orthogonal to the shoreline the formation of hummocky cross stratification by an al ng shore flow component superimposed on oscillatory wave motion is not supported by paleocurrent data rather much of the evidence from the ancient record suggests that hummocky cross stratification forms under high energy oscillatory flow with a weak shore normal combined flow component the orientation of wave ripple crests from the lower shoreface to offshore transitional zone of wave dominated coasts can be used to approximate the local paleoshoreline trend the paleocurrent data from the ancient examples suggest a strong predominance of offshore directed sediment transport as opposed to the nearly shore parallel orientation of currents observed in modern geostrophic flows

combined flow model for vertical stratification sequences in shallow marine storm deposited beds abstract we develop a model to help explain the wide variety of vertical stratification sequences in shallow marine sandstones this model embodied in a set of vertical sequence cartoons predicts or accounts for vertical stratification sequences in beds of free sandstone deposited from a full range of decelerating combined flows as well as from purely unidirectional and oscillatory flows according to the model vertical stratification sequences in storm deposited sandstone beds are the outcome of the time history of the bed configuration as deposition proceeds the idealized sequences are based on the initial velocities and subsequent deceleration histories of the unidirectional and oscillatory flow components twenty qualitatively different sequences starting with plane bed are generated and an additional 26 sequences result from omitting one or more of the lowermost intervals in succession the model thus accounts for 46 distinct kinds of sequences five major simplifying assumptions are built into the model bidirectional flows linear deceleration of both unidirectional and oscillatory flow components time independent deposition rate time independent sediment size and equilibrium bed configurations owing to these assumptions the model is likely to be applicable to only a small subset of vertical stratification sequences observed in shallow marine sandstones as more information on combined flow bed configurations becomes available these assumptions could be relaxed to provide a more refined and complete representation of vertical stratification sequences since the model generates vertical sequences formed from any kind of decelerating flow the bouma sequence for deposits from purely unidirectional turbidity currents and also sequences resulting from decelerating purely oscillatory flows similar in appearance to many proposed generalized tempestite sequences are end member cases in the model the model is also extended slightly to explain the geometry of the uppermost bedding surfaces of storm generated sandstones by consideration of disequilibrium effects

late carboniferous and early permian drainage patterns in atlantic canada paleoflow data have been compiled for late carboniferous late westphalian a to early permian alluvial deposits over a large area of atlantic canada the data which include more than 36 000 measurements of large scale trough cross strata indicate a predominantly northeasterly paleoflow and suggest that a major source area lay to the southwest of the region throughout the 30 ma period represented uplands within the basin deflected paleoflow and probably formed important local drainage and sediment sources tectonostratigraphic analysis suggests that the drainage originated in the fold and thrust belt of the central appalachians and parts of the northern appalachians rivers probably followed northeast oriented structural lineaments through the older acadian mountains of the northern appalachians a considerable proportion of the rising orogen s drainage and probably detritus may have traversed basins along the strike of the mountain belt a situation analogous to that of the modern himalayas

paleomagnetic evidence for rotation during stephano permian extension in southern massif central france we present results of a preliminary paleomagnetic study devised as a test of a tectonic model proposed by van den driessche and brun 1 to interpret the main structural features of the montagne noire south massif central france this model suggests that crustal extension during stephanian to permian times is responsible for a major fiat lying detachment the inferred geometrical relationships between fault azimuth and extension direction is befieved to induce a counter clockwise rotation of the paleozoic cover during its northward motion in order to test this model we have sampled autunian lower permian grey and red sandstone beds within two basins opened during the extension the lod ve and the st affrique basins the paleomagnetic study of six sites three in each basin using thermal demagnetization procedures reveals the presence of 3 magnetization components a first one a which is unblocked below 400 o c is interpreted as a recent overprint due to weathering of the sandstones the b component is unblocked between 400 o and 575 o c this b component is assumed to be primary although the gentle dip of the beds does not allow a fold test it fits the lower permian field direction in the lod ve basin in situ d m 194 i m 6 o k 50 tilt corrected d m 194 i m 10 o k 53 in contrast it shows a systematic difference in declination in the st affrique basin in situ d m 173 i m 2 5 o k 101 tilt corrected d m 172 lm 6 o k 37 this is interpreted as a post autunian counter clockwise rotation of at least 20 o of the st affrique basin thus supporting one of the main implications of the tectonic model finally red sediments from two sites of the lod ve basin yield a third component c with unblocking temperatures up to 670 c and carried by hematite its direction is also consistent with the permian field direction showing that hematite crystallisation occurred early in the diagenesis history of the sediments

eolian sequence and erg dynamics the permian corrie sandstone scotland abstract a nearly 700 m thick sequence of permian erg deposits was preserved in a rapidly subsiding inland basin arran scotland the eolian sequence is composed of more than 30 superimposed erg units separated by erg order deflation super bounding surfaces each erg unit 6 to 72 m in thickness mean 22 m is initiated by flat bedded eolian sandstones 0 5 to 7 0 m in thickness mean 2 9 m of amalgamated interdraa or interdune origin and is topped by cross bedded draa or dune sandstones 3 to 70 m in thickness mean 18 m the eolian sequence represents alternating episodes of erg accumulation and erg deflation these alternating constructional and destructional phases are related to climatic oscillations determining sand supply to the erg system in the vertical dimension the erg units define six complete megacycles 62 to 184 m in thickness mean 110 m each of which is composed of four to six erg units basic cycles the origin of this composite cyclicity is viewed in the light of permian orbital climatic forcing and glacial cycles finally the dynamics of the corrie erg is compared to two permian coastal erg systems in north america

pot and gutter casts from the chapel island formation southeast newfoundland abstract member 2 of the chapel island formation of southeast newfoundland contains a diverse suite of erosional structures known as pot and gutter casts these are particularly abundant in a lithofacies deposited in a nearshore zone characterized by erosion and sediment bypass during storm emplacement of sands the steep to overhanging walls of both pot and gutter casts imply rapid filling during the same storm events that created these depressions erosion is thought to have taken place under strong offshore directed unidirectional flow storm surge or other relaxation flow as with many sandstone tempestites the initial stages of the storm events were dominated by strong and in this case highly erosive unidirectional flow and the latter stages by oscillatory flow as evidenced by wave diagnostic lamination in the sandy infills pot casts have geometries and soles indicating vortex flow similar to that which forms potholes in bedrock in glaciated regions gutter casts that lead into potholes do so at their edge a requirement for generating rotary currents within the depression pot casts are commonly tilted relative to paleohorizontal and their direction of plunge is either upcurrent or downcurrent variation in geometry of the erosional structures from the chapel island formation and from erosional structures in general can be accounted for by the following substrate type diagenetic history of substrate and flow parameters such as pattern of water motion velocity and intermittency of flow

the atlas east variscan elbe shear system and its role in the formation of the pull apart late palaeozoic basins the variscan orogeny occurred as a result of the late devonian to late carboniferous collision and accretion of gondwana derived microcontinents and continental masses with those of laurussia the irregular boundaries of the colliding continents caused isochronous transpressional and transtensional tectonics accompanied by a complex pattern of intracontinental shear zones at the scale of the southern european variscides these shear zones and their configuration controlled the subsequent evolution of permian to middle triassic paleogeography the geographic distribution from morocco to the eastern alps of the late carboniferous permian up to triassic basins most of which are considered as pull apart basins was related with the development of the late palaeozoic intracontinental shear network our analysis of the stratigraphic tectonic and volcanic features of the late carboniferous permian continental basins across the laurussia gondwana boundary reveals the role of the east variscan shear zone during this time as a precursory lineament for the development of the permian to triassic rifting of pangaea and the following opening of oceanic basins e g the neothetyan ocean

a highstand oolitic sequence and associated facies from a late triassic lake basin south west england high energy lake shoreline carbonate sequences are rarely documented in the geological record however one example occurs in the upper triassic mercia mudstone group mmg of southern britain the mmg is one of a number of thick non fossiliferous mudstone deposits associated with north atlantic mesozoic rift basins the origin of the mmg mudstones is the subject of current debate with marine playa lacustrine and alluvial aeolian models having been proposed shoreline features have been documented from the northern margin of the basin but the rarity of such features elsewhere in the mmg has led many workers to doubt a lacustrine origin for the mudstones wave dominated lake shoreline deposits have been recognized in several sections from the southern basin margin in the clevedon area of the bristol channel in south west england these deposits provide evidence for the development of a sizeable perennial to semi perennial hypersaline lake in which the mmg mudstones accumulated shoreline sediments overlie alluvial stream and sheet flood deposits and pass from transgressive gravel conglomerate beach units with bioclasts influenced by shore normal waves deposited under semi humid conditions to lower gradient highstand oolitic sands affected by more varied wave approach deposited under progressively more arid conditions which culminated in lowstand oolitic strand plain deposits overlain by a playa mudflat unit shoreline deposits record a simple shallowing upward transgressive highstand lowstand sequence however a change from a reflective transgressive to dissipative highstand shoreline is believed to represent a climatically induced change in prevailing wind direction shoreline features recognized in the mmg are similar to those of recent playa lacustrine basins of the western united states ooids display a variety of size fracture and dissolution features in addition to beachrock fabrics suggesting that they were originally composed of radial aragonite similar to modern ooids from the great salt lake utah

comment on chronostratigraphy and paleoclimatology of the lodeve basin france evidence for a pan tropical aridification event across the carboniferous permian boundary by michel l a tabor n j montanez i p schmitz m d davydov v i 2015 palaeogeography palaeoclimatology palaeoecology 430 118 131

pangaean climates megamonsoons of the megacontinent the climate for a highly idealized geographic representation of the megacontinent of pangaea corresponding to the period 250 200 m y ago is explored using a low resolution atmospheric general circulation model that is coupled to a static mixed layer ocean of constant depth with a provision for sea ice formation and decay soil moisture is included as a predicted variable on the continent because there are large uncertainties about key factors that might influence the pangaean climate sensitivity experiments are used to examine the climate for two different mean elevations 0 and 1000 m two different snowcover prescriptions and two different levels of implied greenhouse heating and solar luminosity modern co2 concentration and modern solar luminosity fivefold increase in modern co2 concentration and a 1 decrease in modern solar luminosity in all of the experiments the large bipolar land masses of laurasia and gondwanaland joined near the equator in the west and separated by the tethys sea in the east exhibit extreme continentality with hot summers cold winters and large scale summer and winter monsoon circulations year round or seasonal aridity is simulated for all but the eastern coastal regions the tropical western coast and the regions poleward of 40 latitude the simulated climate of the idealized pangaean continent has many features that correspond qualitatively with geologic evidence for tropical warmth and aridity in the late permian and triassic however the model results serve mainly to indicate the importance of various climate forming factors geography topography heating detailed comparisons will require new experiments with better models and more accurate geologic boundary conditions

sedimentation in large lakes processes associated with sedimentation in these lakes is in its infancy the large lakes of the world are precious resources that provide their nearby inhabitants with abundant fresh water food economical transpor tation and recreation they also provide additional benefits to the geologist unique paleoclimatic records and useful basins in which to test models of aquatic sedimentary processes this paper summarizes the global distribution oflarge lakes and focuses upon their geological attributes

reply to the comment on chronostratigraphy and paleoclimatology of the lodeve basin france evidence for a pan tropical aridification event across the carboniferous permian boundary by michel et al 2015 palaeogeography palaeoclimatology palaeoecology 430 118 131 abstract michel et al 2015 present new radioisotopic age estimates coupled with paleosol data from the lodeve basin france that indicate a pennsylvanian permian trend toward aridity that is similar to trends seen in other western equatorial basins across tropical pangaea in their comment pochat and van den driessche 2015 call into question these newly published u pb zircon chemical abrasion isotope dilution thermal ionization mass spectrometry ca idtims age estimates from volcanic ash layers preserved within the lodeve basin furthermore pochat and van den driessche 2015 reject our assertion that the rates of sediment accumulation for the carboniferous permian strata in the lodeve basin are in need of recalculation as a result of the new geochronological dates finally pochat and van den driessche 2015 suggest that the paleosol data presented in michel et al 2015 do not provide meaningful proxies of paleoclimate change and reassert the position presented in pochat and van den driessche 2011 that sedimentary strata are not strongly affected by paleoclimatic change compared with the influence of tectonic processes of the lodeve basin

time sequence observations of wave formed sand ripples on an ocean shoreface analysis of an 18 day time lapse film record of shoreface ripple development with concurrent measurements of near bottom flow and surface waves provides new insight on equilibrium bedform conditions adjustment of ripple planform to variable hydrodynamics and ripple migration behaviour the study was conducted in approximately 10 m water depth 1 km off martinique beach on the atlantic coast of nova scotia canada under low energy summer wave conditions significant wave height and peak period during the study averaged 0 7 m and 8 s respectively with extremes up to 1 7 m and 11 s during passage of three weak weather disturbances six mutually exclusive ripple types have been defined 1 short wavelength regular ripples 2 variable bifurcated ripples 3 variable terminated ripples 4 short crested ripples 5 long wavelength regular ripples and 6 chaotic ripples ripple wavelength ranged from 0 07 m to 0 24 m and displayed a strong reynolds number dependence together with other published field data the results suggest a lower limit of 0 06 m for the wavelength of wave ripples in ocean shoreface environments ripple orientation ranged through 38 and responded rapidly to changes in wave approach direction but did not conform to the orientation of the adjacent shoreline ripples were observed to migrate both on and off shore with and against the wave advance direction at rates up to 0 1 m h 1 associated with net flows other than wave induced onshore asymmetry and mass transport migration mainly of ripple types 1 and 2 occurred during the peak of storm events but showed no obvious correlation with measured near bottom flow magnitude or direction ripple behaviour demonstrates equilibrium with prevailing dynamic conditions when straight crested rippie types 1 and 5 are present disequilibrium in orientation or dimensions is expressed by increasing sinuosity bifurcation and crest termination in types 2 3 4 and 6

analytical method for estimating palaeowave climate and water depth from wave ripple marks analytical expressions are developed for evaluating palaeodepth and palaeowave conditions from wave ripple marks palaeodepth and palaeowave climate estimates can be extremely powerful predictors in reconstructions of vertical movements related to basin subsidence local and regional ancient wave climate trends and the basin shape the analytical expressions developed herein are applied to wave ripple marks preserved in the lower marine molasse of switzerland western austria and southern germany the results suggest that in contrast to traditional concepts of an eustatic sea level change the lower marine molasse regression was a result of mainly depositional processes the subsidence rate greatly exceeded the rate of sea level fall over a wide geographical area furthermore the widening of the lower marine molasse basin to the ene is well documented by the increase of the ancient wave period and wave power calculated from wave ripple marks found in storm deposits

detrital cosmogenic 21ne records decoupling of source to sink signals by sediment storage and recycling in miocene to present rivers of the great plains nebraska usa the preservation of conglomerates far from mountainous sources is commonly interpreted in terms of tectonic or climatic forcing to relate a depositional signal to changing conditions in source areas the process and duration of sediment routing from source to sink need to be determined for the first time we quantified sediment transport histories using cosmogenic 21ne in quartzite pebbles from modern river gravels and neogene conglomerates from the modern and ancient north platte river of the great plains of nebraska united states we demonstrate that at 400 km distance from the front ranges of the rocky mountains the majority of pebbles were stored in older channel deposits for up to several millions of years before being recycled this was enabled by very slow to zero basin subsidence rates this implies that upstream tectonic or climatic controls on surface processes were decoupled from the downstream depositional record a result supported by the similarities in cosmogenic 21ne values among miocene pliocene and modern river channel pebbles despite known changes in tectonic and climatic forcing

hercynian high altitude phenomena in the french massif central tectonic implications abstract stratified slope deposits diamictite and sedimentary structures such as water escape craters ghosts of ice crystals and solifluction flowage in the stephanian autunian of the french massif central are related to high altitude periglacial effects the clay mineral assemblage dominated by the association illite chlorite irregular interlayed clays and the slight weathering of feldspathic clasts and granite gneiss pebbles favour the prevalence of a cold to temperate climate at this time rather than a hydrolyzing climate of humid equatorial or tropical type the flora and entomofauna also indicate a seasonally varying climate with cold winters favouring the development of periglacial phenomena at high altitude in view of the equatorial paleogeographic position of the hercynian belt this type of climate could exist only at altitudes higher than 4500 m the tectonic implications of these altitudes are examined through a comparison with the present day himalayas and tibetan plateau

aeolian stratification and facies association in desert sediments arran basin permian scotland abstract permian aeolian sediments on the island of arran are divisible into dune including draa and interdune deposits both types display a distinctive and unusually wide variation in grain size the dominant features of the dune deposits are grainfall lamination sandflow lamination and inverse graded lamination associated with ripple form lamination and normal graded lamination the flat lying aeolian interdune deposits are characterised by granule and sand ripples horizontal lamination in coarse sand and granules plane bed lamination and inverse graded lamination associated structures include ripple form lamination and deflation lags three types of trace fossil associated with completely bioturbated horizons occur in some low angle dune and interdune deposits the aeolian facies interfinger with alluvial fan deposits giving rise to three recognizable facies belts marginal aeolian deposits are associated with fluvial conglomerates and are dominated by interdune deposits and occasionally very thin barchan deposits set height 3 37 cm intermediate aeolian deposits are characterized by interbedded crescentic dune small draa dune set height 5 cm 4 5 m and interdune deposits and rare fluvial and lake sediments basinal aeolian deposits are dominated by draa deposits dune set height 0 2 28 m associated with rare interdune sediments transverse dunes and draas were moved by north eastern palaeowinds towards the foot of the alluvial fans the aeolian sediments were deposited in a fault bounded desert basin

contribution of late permian palaeogeography in maintaining a temperate climate in gondwana numerical simulations based on general circulation and energy balance models consistently indicate that the high latitudes of gondwana experienced seasonal extremes in climate during the late permian period1 3 but palaeogeographic maps based on the distribution of climate sensitive rocks4 palynological and palaeobotanical data5 6 and dicynodont fossil records7 all imply a temperate climate the reason for this discrepancy has not been clear recently it has emerged from studies of upper permian fluviolacustrine deposits throughout southern africa that the geography was dominated by a series of giant lakes perhaps interconnected within major fluvial frameworks8 here i review these data and their implications for a temperate climate i suggest that the discrepancy between the climate modelling results which indicate seasonal temperature extremes and the increasing body of geological information documenting a temperate climate may be explained by the fact that the palaeogeography used in the models does not take into account the existence of these lakes and rivers which would have had a major influence on the regional climate the results demonstrate the importance of incorporating accurate palaeogeographies into numerical modelling studies when attempting to reconstruct past climates

sedimentology and stratigraphy of cenozoic deposits in the kagizman tuzluca basin northeastern turkey the kagizman tuzluca basin is located in the northeastern anatolia to the east of the intersection point near karliova of the major north and east anatolian fault systems this intermontane basin displays a thick sequence over 2000 m of mostly terrestrial deposits represented by repetitive alternations of the lake and fluvial environments ranging from late eocene oligocene to middle late miocene a marine incursion only mappable in the southeastern margin of the basin deposited limestones and sandy limestones rich in marine mollusks and nummulites in particular n fichteli that constrain an early oligocene age for this marine unit kagan fm the terrestrial basin fill deposits show different thicknesses throughout the basin due to irregular bottom topography and tectonic configuration of the basin margins the thickest deposits were accumulated along the different margins of the basin which received high quantities of siliciclastics from meandering river alluvial and coastal fans fan delta gilbert type delta and wave worked fluvial delta climate changes have also driven the development of lake environments during distinct depositional periods siliciclastic dominated overfilled lakes halikislak and kizilkaya formations and chemical dominated underfilled lakes turabi and tuzluca formations were formed they have been also classified as newark type and fundy type lakes respectively fluvial systems evolved from high energy meandering rivers deposited under humid climate gungoren formation to low energy meandering rivers resulted from arid and semiarid climates cincavat formation the transitional intervals from ephemeral river dry mudflat cincavat formation to saline pan lake tuzluca formation indicate wadi sand flat playa fluvial systems the chronostratigraphic constrains of the entire sequence remain poor and so far solely based on vertebrate fossil assemblages the evaporitic tuzluca formation would be middle miocene in age due to its stratigraphic position over the cincavat formation