near surface deformation in the new madrid seismic zone as imaged by high resolution sh wave seismic methods over 1 5 kilometers of high resolution sh wave refraction and reflection profiles have been performed in the madrid bend area of northwestern tennessee approximately 8 km north of tiptonville tennessee to establish the existence of neo tectonic near surface deformation the specific area was chosen because of the access it provided to the tiptonville dome a holocene flexure and the trend of contemporary seismicity within the new madrid seismic zone nmsz we believed the highest likelihood of near surface deformation to be over these features partially reversed refraction reflection walk away tests and common depth point cdp seismic profiling using the non traditional sh wave method have traced antiformal flexure and numerous faults into the late eocene and holocene sediments of the tiptonville dome province of the lake county uplift lcu vertical displacements exhibited across the faults range from approximately 3 to 30 m these structures have been interpreted to be neo tectonic features associated with tensional stresses across the tiptonville dome

elevated lateral stress in unlithified sediment midcontinent united states geotechnical and geophysical indicators for a tectonic origin abstract indirect and direct geotechnical measurements revealed the presence of high lateral earth pressure ko in shallow unlithified sediment at a site in the northernmost mississippi embayment region of the central united states results from pile load and pressuremeter tests showed maximum ko values greater than 10 however the complex geologic environment of the midcontinent made defining an origin for the anomalous ko based solely on these measurements equivocal although in situ sediment characteristics indicated that indirect tectonic or nontectonic geologic mechanisms that include transient overburden loads e g fluvial deposition erosion glacial advance retreat and dynamic shear loads e g earthquakes were not the dominant cause they were unable to provide indicators for a direct tectonic generation localized stresses induced anthropogenically by the geotechnical field tests were also considered but ruled out as the primary origin a high resolution shear wave sh reflection image of geologic structure in the immediate vicinity of the test site revealed compression style neotectonism and suggested that the elevated stress was a tectonic manifestation post paleozoic reflectors exhibit a tertiary structural inversion as evidenced by post cretaceous fault displacement and pronounced positive folds in the hanging wall of the interpreted faults the latest stratigraphic extent of the stress effects i e all measurements were in the late cretaceous to tertiary mcnairy formation as well as the relationship of stress orientation with the orientation of local structure and regional stress remain unknown these are the subjects of ongoing studies

fluvial responses to tectonics and climate change during the late weichselian in the eastern part of the pannonian basin hungary abstract fine grained sandy silty channel belt and floodplain deposits of the berettyo koros rivers a main eastern transverse tributary system of the modern tisza river in the eastern part of the pannonian basin were deposited during the late pleistocene under net subsiding conditions the palaeo drainage network pattern of a 2500 km 2 large part of the alluvial plain was reconstructed based on interpretation of airborne photographs and analysis of 18th century topographic maps which show the natural river patterns that predate the introduction of river regulation schemes the investigation showed that a large meandering river system with two main channel belts surrounding a floodbasin entered the alluvial plain from the northeast and a braided river entered the alluvial plain from the southeast detailed sedimentary logs of seven continuous corings and several sand and clay pit sections were used to characterize different alluvial units optical luminescence dating osl of 25 quartz samples and four 14 c datings showed that the sediments are of late pleniglacial to late glacial age transport directions inferred from heavy mineral analyses combined with the osl ages strongly suggest that the large meandering system represents the palaeo tisza river which supposedly flowed along the northeast southwest striking ermellek depression during the late pleniglacial the braided river can be regarded as a precursor to the fekete and feher koros rivers which entered the alluvial plain from the southeast during the late glacial the interpretation of seismic profiles field measurements of neotectonic activity and variations in thickness of sediments along the studied profile revealed that river development was largely controlled by subsidence along the ermellek depression until 14 to 16 ky and by uplift of the southeastern part of the catchment area the studied fluvial successions also document the response of the palaeo tisza and koros system to the climate changes of the weichselian late pleniglacial late glacial period much of the sand from the meandering zones was deposited during the bolling allerod and sagvar lascaux interstadials whereas some dated sand units from the braided zone represent the older and younger dryas the error ranges of osl dates which often exceed the duration of weichselian substages and subdivisions prevented an unambiguous correlation of the studied sections with the millennial scale climate changes of the last 25 ky meandering and braided river activity coexisted under different climate conditions whereas locations of the main channel belts are related to subsidence anomalies the results of our study thus clearly indicate that tectonics was the primary control on river development

quaternary grabens in southernmost illinois deformation near an active intraplate seismic zone abstract narrow grabens displace quaternary sediments near the northern edge of the mississippi embayment in extreme southern illinois east central united states grabens are part of the fluorspar area fault complex fafc which has been recurrently active throughout phanerozoic time the fafc strikes directly toward the new madrid seismic zone nmsz scene of some of the largest intra plate earthquakes in history the nmsz and fafc share origin in a failed cambrian rift reelfoot rift every major fault zone of the fafc in illinois exhibits quaternary displacement the structures appear to be strike slip pull apart grabens but the magnitude and direction of horizontal slip and their relationship to the current stress field are unknown upper tertiary strata are vertically displaced more than 100 m illinoian and older pleistocene strata 10 to 30 m and wisconsinan deposits 1 m or less no holocene deformation has been observed average vertical slip rates are estimated at 0 01 to 0 03 mm year and recurrence intervals for earthquakes of magnitude 6 to 7 are on the order of 10 000s of years for any given fault previous authors remarked that the small amount of surface deformation in the new madrid area implies that the nmsz is a young feature our findings show that tectonic activity has shifted around throughout the quaternary in the central mississippi valley in addition to the nmsz and southern illinois the wabash valley illinois indiana benton hills missouri crowley s ridge arkansas missouri and possibly other sites have experienced quaternary tectonism the nmsz may be only the latest manifestation of seismicity in an intensely fractured intra plate region

tertiary and quaternary tectonic faulting in southernmost illinois abstract tertiary and or quaternary tectonic faulting is documented in three areas of southernmost illinois the fluorspar area fault complex fafc in pope and massac counties the ste genevieve fault zone sgfz in alexander and union counties and the commerce fault zone cfz in alexander county in the fafc faults that strike ne and nne displace mounds gravel late miocene to early pleistocene and locally the metropolis terrace gravel pleistocene pre woodfordian no woodfordian or younger deposits are deformed faults typically outline narrow linear grabens that formed under tension with a component of strike slip north south to nw trending vertical faults near the southeast end of the sgfz displace eocene sediments again faults outline narrow grabens and show indications of strike slip deformed quaternary sediments have not been observed the cfz which trends northeast displaces mounds gravel in illinois and units as young as peoria silt woodfordian in missouri quaternary movement has been interpreted as right lateral strike slip the cfz coincides with a subtle gravity and magnetic lineament and seems to reflect a major feature in the basement surface expression in illinois is subtle but mafic and ultramafic intrusions hydrothermal alteration and small faults align with the commerce geophysical lineament earthquake foci in missouri and illinois lie on or close to the cfz some focal mechanisms fit the fault trend among these structures only the cfz exhibits slip that conforms to the current stress field principal compressive stress axis e w to ene wsw possibly the stress field changed during neogene time alternatively high fluid pressures or local stress concentrations may have induced slip on less favorably oriented fractures tighter constraints are needed on timing magnitude and direction of neogene displacement

long term fluvial archives in hungary response of the danube and tisza rivers to tectonic movements and climatic changes during the quaternary a review and new synthesis abstract the paper discusses the quaternary evolution of the danube and tisza rivers and their main tributaries in the context of evolution of the entire pannonian basin which is europe s largest intramontane basin within the alp carpathian orogen the palaeo drainage reconstruction of the pannonian basin for the pre quaternary period is outlined in connection with the gradual regression of lake pannon since the late miocene deltas of rivers that entered the basin from the northwest and northeast were gradually transformed into extended alluvial plains thus the earliest possible ancestor of the danube coming southeastwards from the alps could be as old as late miocene by the pliocene the whole lake pannon was infilled the former extensional basin formation was replaced by a compresional stress field which resulted in an uplift of the marginal flanks and late stage subsidence anomalies the increasing relief led to the formation of the quaternary drainage pattern the actively subsiding young basins were filled by fluvial sediments transported by the danube and tisza river systems from the uplifting mountains between the subsiding regions of the little and great plains the danube has formed an antecedent valley with terrace staircases between the uplifting sections of the transdanubian range and the north midmountains the formation of the terraces is attributed to periodic climate changes during the pleistocene combined with differences in the uplift rate the paper gives a complex overview of the classical chronology of the six terraces based on various data sources mostly dating of loess paleosol sequences travertines aeolian sand and tephra strata overlying the fluvial sediments complemented by scattered vertebrate faunal data and archaeological evidence directly from the terrace sediments the quaternary drainage pattern evolution of the great plain with a strong tectonic control is discussed in detail rivers originating from the uplifting marginal areas were drawn towards the subsiding depressions which served as local base level changes in subsidence rates in space and time throughout the quaternary resulted in the evolution of a complex drainage pattern a special emphasis is placed on the late pleistocene holocene development of the middle tisza region and the koros basin where the berettyo koros rivers form an eastern tributary system of the tisza river a comparative evaluation of these two areas is especially relevant as they provide insights into large scale late pleistocene avulsion of the tisza river osl dating complemented with inferred transport directions determined from heavy mineral analysis of fluvial sediments in the koros basin has revealed an ancient large meandering river system that can be identified with the palaeo tisza which was flowing along a tectonically controlled depression during the late pleniglacial successions in the middle tisza region have allowed differentiation between the older channels of the palaeo bodrog river and the sajo hernad alluvial fan and the younger meander belts of the new course of the tisza in the tisza system changes in river style braided to various scales of meandering show correspondence to millennial scale climate changes of the last 25 ka while in the koros basin the effects of tectonics are overprinted onto the regional climatic signals

quatermalacological analyses for modeling of the upper weichselian palaeoenvironmental changes in the carpathian basin abstract the late pleistocene environmental history of the carpathian basin can be regarded as one of the missing links to our understanding of the last glacial development of europe changes in the radiocarbon dated mollusc faunas of the loess areas along with the palaeogeographic interpretations implied by them seem to underlie the latest results gained from radiocarbon dated pollen analysis of the region changes in the mollusc fauna refer to nine short lived 1000 3000 years cyclical palaeoclimatological alterations which repeatedly transformed the palaeoecological conditions and vegetation in the carpathian basin between 34 and 12 kyr on the basis of malacological data the presence of a major palaeoclimatic trend could be assumed for periods of both warming and cooling in the carpathian basin the mildest july palaeotemperatures were recorded in the sw parts and the coldest ones were recorded in the ne parts of the basin humidity and vegetation cover displayed a large scale mosaic type heterogeneity reflecting the modifying effect of local factors it seem that the upper weichselian environment was mosaic or mosaic like in the carpathian basin and the different plants and animals spread from different ecological spots during periods of climate change when the distribution of the forest grassland ecotone or tundra like habitats changed

river terrace systems in north west europe an archive of environmental change uplift and early human occupation abstract staircases of large scale aggradational river terraces are a notable feature of many valleys in the temperate lattitudes particularly in areas beyond the reach of the erosive activities of pleistocene ice sheets it is now recognized that the cyclic fluctuations of climate during the quaternary have driven the generation of terraces through the direct and indirect influence of both temperature and precipitation on fluviatile activity where fossiliferous deposits are preserved within terrace sequences it is often possible to date these and to correlate them with the oceanic record thus providing an important framework for the evidence of environmental change on land middle and late pleistocene terraces in different areas can commonly be seen to have formed in synchrony with glacial interglacial cycles or with longer periodicity megacycles climatic forcing alone is insufficient to cause terraces to form however uplift is also necessary so that terrace sequences can provide a useful record of crustal movement in northwest europe where some of the best known studies of river terrace sequences have been carried out the fluviatile deposits are also an important repository for palaeolithic artefacts from which a record of early human occupation can be reconstructed

tectonic history of the illinois basin the illinois basin began as a failed rift that developed during breakup of a supercontinent approximately 550 ma a rift basin in the southernmost part of the present illinois basin subsided rapidly and filled with about 3 000 m of probable early and middle cambrian sediments by the late cambrian the rift bounding faults became inactive and a broad relatively slowly subsiding embayment extending well beyond the rift and open to the iapetus ocean persisted through most of the paleozoic era widespread deformation swept through the proto illinois basin beginning in the latest mississippian continuing to the end of the paleozoic era uplift of basement fault blocks resulted in the formation of many major folds and faults the timing of deformation and location of these structures in the forelands of the ouachita and alleghanian orogenic belts suggest that much of the deformation resulted from continental collision between north america and gondwana the associated compressional stress reactivated the ancient rift bounding faults upthrusting the northern edge of a crustal block approximately 1 000 m within the rift concurrently dikes radiometrically dated as early permian sills and explosion breccias formed in or adjacent to the reactivated rift subsequent extensional stress probably associated with breakup of pangea causedmore the crustal block within the rift to sink back to near its original position high angle northeast to east west trending normal faults with as much as 1 000 m of displacement formed in the southern part of the basin these faults displace some of the northwest trending early permian dikes structural closure of the southern end of the illinois basin was caused by uplift of the pascola arch sometime between the late pennsylvanian and late cretaceous less

accelerated uplift resulting from anglian glacioisostatic rebound in the middle thames valley uk evidence from the river terrace record abstract a relatively simple analysis of the terraces of the middle thames valley reveals a complex sequence of responses to late anglian late middle pleistocene drainage disruption a decrease in the amounts of vertical incision separating the later post anglian terraces strongly suggests a major change in the rate of incision in the middle thames area in the post anglian a late anglian and early post anglian incision rate of 1 45 m ka 1 was quickly replaced by incision at a rate of 0 089 m ka 1 in the later post anglian period the lower incision rate of the later post anglian compares favourably with previous estimates of regional uplift two plausible explanations for the enhanced incision in the late anglian and early post anglian are recognized one related to ponding of the river by anglian ice and the other to glacio isostatic rebound in the latter case the mismatch between expected and actual heights of late anglian deposits would suggest glacio isostatic uplift of the order of 22 25 m

k o ocr relationships in soil the relationships between k o and ocr are investigated for primary loading unloading reloading conditions the study reviews laboratory data from over 170 different soils and presents an approach common to clays silts and sands simple empirical methods for predicting k o for normally consolidated and overconsolidated soils are evaluated the validity of the methods is supported by statistical analyses on the basis of the findings only the effective stress friction angle o and prior stress history ocr and ocrmax are needed to predict approximate values of k o

paleogeographic evolution of the late miocene lake pannon in central europe abstract the paleogeographic evolution of lake pannon within the pannonian basin is reconstructed with eight maps ranging from the middle miocene to the early pliocene the maps are based on the distribution of selected biozones and specific fossils and on complementary sedimentological and seismic information our reconstruction shows that the history of lake pannon can be divided into three distinct intervals an initial stage with low water level which resulted in isolation from the sea at about 12 ma and might have led to temporary fragmentation of the lake an interval of gradual transgression lasting until ca 9 5 ma and a long late interval of shrinkage and infilling of sediments that persisted into the early pliocene the deep subbasins of the lake formed during the transgressive interval in more basinward locations than the deep basins of the preceding sarmatian age the southern shoreline running parallel with the sava and danube rivers along the northern foot of the dinarides changed very little during the lifetime of the lake while the northern shoreline underwent profound changes

climate related river activity at the weichselian holocene transition a comparative study of the warta and maas rivers huvial systems from the dutch and polish lowlands are compared for their evolution during the weichselian deglaciation period in both regions the pleniglacial braided river pattern changed to a meandering pattern in the beginning of the lateglacial several transitional stages between braided and high sinuosity meandering systems have been recognized a difference in fluvial activity is found during the younger dryas when the maas transformed to a braided pattern while the warta maintained its meandering pattern phases of erosion and aggradation are more or less synchronous in the different river basins but their intensity may differ greatly the major characteristics of the fluvial systems are obviously a response to the general climatic evolution and related to changes in vegetation the regional differences are of minor importance and can be explained by site specific factors threshold values within the latter factors define the changes in river dynamics

river response to variations of periglacial climate in mid latitude europe abstract the last glaciation was characterised by considerable changes in climate many european river basins reacted to these changes by initial incision and subsequent pattern change earlier research explained this by the time lag of vegetation development after a climatic change which considerably affected the sediment load however since some river basins react differently or do not react at all this model needs to be refined this paper deals with the fluvial evolution of several rivers in northern and central europe during the last glaciation and two of them the weise elster river in the leipzig area and the spree river in the niederlausitz germany are discussed in more detail the vegetation cover on the floodplain in combination with the presence of frozen ground which affects the discharge characteristics largely determines the river type nevertheless when the sequences are compared not only synchronous changes in fluvial development may be observed but also distinct differences in fluvial development by analysing the different rivers in their varying geomorphological settings it appears that grain size basin configuration and catchment size are important parameters also which can determine whether a threshold is exceeded or not

pseudogleyed loess derivates the most common soil parent materials in the pannonian region of croatia abstract loess derived sediments represent the most widespread soil parent materials in the pannonian region of croatia pseudogley as the most common soil type in this region developed mainly on such parent materials pseudogleys largely correlate with the wrb reference soil group of stagnosols on the general soil map of croatia at scale 1 50 000 gsm of croatia the distinction is made between pleistocene loams pl and loess as pseudogley parent materials the initial purpose of this research was to investigate if the criteria for this distinction were clear and consistent and if the terms used for labeling these parent materials were adequate hence we investigated parent materials of 18 pseudogleys across 6 different locations three on loess and three on pl in the pannonian region of croatia we analyzed their morphology including micromorphology of three representative parent materials particle size distribution total porosity ph and mineral assemblages by modal analysis of three representative parent materials following these analyses no systematic differences between the loess parent materials and the pl parent materials were found additionally it was concluded that due to significant geogenetic and or pedogenetic alterations of all studied parent materials none of them should be labeled simply as loess hence parent material at one location was labeled as leached loess derivate and parent materials at all other locations were labeled as pseudogleyed loess derivates both types of parent materials were described in detail and defined in addition the terminology and the classification of loess derived parent materials in general was proposed the analyzed pseudogleyed loess derivates were not completely uniform across the investigated locations primarily this was due to the polygenesis of loess reflected by differences in particle size distributions and compositions of light and heavy mineral fractions secondarily it was due to the 600 1100 mm map gradient along the study region reflected by differences in ph values and properties of redoximorphic features although pedogenesis of the investigated parent materials might have started already during the late glacial and have continued throughout the holocene at varying and overall decreasing rates their morphology indicates that pseudogleization and lessivage are still active processes which occur simultaneously in the analyzed parent materials and agree with the present climate

the late quaternary environmental history of batorliget n e hungary abstract a sedimentary sequence extending back into the last glacial has been obtained from batorliget marsh in n e hungary reconstruction of the environmental history of the region using the techniques of pollen analysis molluscan analysis and geochemistry has revealed an important late quaternary refugium during the last glacial a refugium for temperate flora and fauna existed within a landscape dominated by coniferous forest predominantly made up of pinus and picea the lateglacial postglacial transition at 10 000 yr b p resulted in a dramatic shift from coniferous but also including betula woodland to deciduous woodland following the lateglacial postglacial transition a highly diverse woodland became established in the early postglacial accompanied by an equally diverse molluscan assemblage this diversity remained throughout the early postglacial although the types present within the woodland changed a number of times at c 7000 yr b p anthropogenic disturbance resulted in the destruction of the mixed forest and the development of agricultural land the importance of this region as a refugial area both in the lateglacial and early postglacial is discussed and the influence that it had on the postglacial development of the fauna and flora of northeastern hungary is reviewed

the effect of dynamic loading on lateral stress in sand this paper presents the results of a laboratory study on the lateral stress in a vibrated sand no 3 ottawa sand was tested on a snaking table providing vertical vibration and at rest lateral stress was measured using a modified oedometer ring the test results show that the lateral stress in normally consolidated sand increases with vibration time the magnitude of the increase in lateral stress is related to the density of sand and the intensity of vibration for overconsolidated sand with a high coefficient of earth pressure at rest the lateral stress decreases with vibration time stress paths of a tested specimen are also presented in this paper key words sand coefficient of earth pressure at rest lateral stress vibration overconsolidation ratio stress path

the full glacial forests of central and southeastern europe the presence of trees in central and southern europe during the last full glaciation has long been a matter of debate a low but persistent presence of fossil tree pollen in central and southern european full glacial paleoecological sequences has been interpreted either as representing long distance pollen transport from southerly refuges or as representing in situ refugial populations here we present macroscopic charcoal results from 31 sequences located throughout hungary that provide unequivocal evidence for the presence of at least seven different tree types between approximately 32 500 and 16 500 14c yr b p this evidence is presented in conjunction with molluscan and pollen analyses to indicate that during the last full glaciation trees grew as far north as hungary probably in microenvironmentally favorable sites these areas provided an important cold stage refugium for the european flora and fauna

stress induced late stage subsidence anomalies in the pannonian basin abstract subsidence sedimentation and tectonic quiescence of the pannonian basin was interrupted a few million years ago by tectonic reactivation this recent activity has manifested itself in uplift of the western and eastern flanks and continuing subsidence of the central part of the pannonian basin low to medium magnitude earthquakes of the carpathian pannonian region are generated mostly in the upper crust by reverse and wrench fault mechanisms there is no evidence for earthquakes of extensional origin 2 d model calculation of the subsidence history shows that a recent increase in magnitude of horizontal compressional intraplate stress can explain fairly well the observed quaternary uplift and subsidence pattern we propose that this stress increase is caused by the overall europe africa convergence in late pliocene consumption of subductible lithosphere at the eastern margin of the pannonian basin was completed and the lithosphere underlying the pannonian basin became locked in a stable continental frame consequently extensional basin formation has come to an end and compressional inversion of the pannonian basin is in progress

irregular glacial interstadials recorded in a new greenland ice core the greenland ice sheet offers the most favourable conditions in the northern hemisphere for obtaining high resolution continuous time series of climate related parameters profiles of 18o 16o ratio along three previous deep greenland ice cores1 3 seemed to reveal irregular but well defined episodes of relatively mild climate conditions interstadials during the mid and late parts of the last glaciation but there has been some doubt as to whether the shifts in oxygen isotope ratio were genuine representations of changes in climate rather than artefacts due to disturbed stratification here we present results from a new deep ice core drilled at the summit of the greenland ice sheet where the depositional environ ment and the flow pattern of the ice are close to ideal for core recovery and analysis the results reproduce the previous findings to such a degree that the existence of the interstadial episodes can no longer be in doubt according to a preliminary timescale based on stratigraphic studies the interstadials lasted from 500 to 2 000 years and their irregular occurrence suggests complexity in the behaviour of the north atlantic ocean circulation

flow resistance of rock chutes with protruding boulders steep and short rough channels such as rock chutes are used in river restoration as grade stabilization structures the stability of these channels can be increased using boulders placed over the base material the boulders can be placed with different configurations such as randomly or in rows in each case their presence affects the geometry of the channel and modifies the hydraulic resistance this paper shows the results of tests conducted on rough channels with or without the insertion of protruding boulders the parameters that influence the flow resistance such as slope relative submergence and blocks disposition were systematically investigated to describe the hydraulic behavior of the structure the aim is to define a relationship useful for practical design which relates the flow resistance in terms of both darcy weisbach friction factor and manning coefficient the results were combined with available data for loose rock riprap to determine new experimental relationships

seismic reflection images of shallow faulting northernmost mississippi embayment north of the new madrid seismic zone high resolution seismic reflection surveys document tectonic faults that displace pleistocene and older strata just beyond the northeast termination of the new madrid seismic zone at the northernmost extent of the mississippi embayment these faults which are part of the fluorspar area fault complex in southeastern illinois are directly in line with the northeast trending seismic zone the reflection data were acquired using an elastic weight drop source recorded to 500 msec by a 48 geophone array 24 fold with a 10 ft 3 0 m station interval recognizable reflections were recorded to about 200 msec 100 150 m the effects of multiple reflections numerous diffractions low apparent velocity i e steeply dipping noise and the relatively low frequency content of the recorded signal provided challenges for data processing and interpreting subtle fault offsets data processing steps that were critical to the detection of faults included residual statics post stack migration deconvolution and noise reduction filtering seismic migration was crucial for detecting and mitigating complex fault related diffraction patterns which produced an apparent folding of reflectors on unmigrated sections detected individual offsets of shallow reflectors range from 5 to 10 m for the top of paleozoic bedrock and younger strata the migrated sections generally indicate vertical to steeply dipping normal and reverse faults which in places outline small horsts and or grabens tilting or folding of stratal reflectors associated with faulting is also locally observed at one site the observed faulting is superimposed over a prominent antiformal structure which may itself be a product of the quaternary deformation that produced the steep normal and reverse faults our results suggest that faulting of the paleozoic bedrock and younger sediments of the northern mississippi embayment is more pervasive and less localized than previously thought

long term fluvial archives in nw france response of the seine and somme rivers to tectonic movements climatic variations and sea level changes the seine and the somme are the two main rivers flowing from northwestern france into the channel during the pleistocene cold stages both rivers were tributaries of the river manche which was exporting sediments into the central deeps of the channel the river seine has a very well developed terrace system recording incision that began at around 1 ma the same age is proposed for the beginning of the main incision in the somme valley on the basis of morphostratigraphy pedostratigraphy palaeontology palaeomagnetism and esr datings the uplift rate deduced from analysis of the seine and somme terrace systems is of 55 to 60 m ma since the end of the lower pleistocene the response of the two rivers to climatic variations uplift and sea level changes is complex and variable in the different parts of the river courses for example the evolution of the lower seine system is influenced by uplift and climate changes but dominated by sea level changes in the middle seine the system is beyond the impact of sea level variations and shows a very detailed response to climatic variations during the middle and upper pleistocene in a context of uplift the somme valley response appears to be more homogeneous especially in the middle valley where the terrace system shows a regular pattern in which incision occurs at the beginning of each glacial period against a general background of uplift nevertheless the lower somme valley and the palaeo somme in the channel area indicate some strong differences compared with the middle valley influence of sea level variations and probably differences in rates of tectonic uplift between the channel and the present continent the differences in the responses of the two river valleys during the pleistocene are related to differences in the size of the fluvial basins to the local tectonic characteristics to the geometry of the platform connected to the lower parts of the valleys and to the hydrodynamic characteristics of each river finally it is shown from these examples that the multidisciplinary study of pleistocene rivers is a very efficient tool for the investigation of neotectonic activity

resistance equation for large scale roughness a theory of flow resistance for large scale roughness is developed the main points of which are supported by a flume study from which the outline of a process based resistance equation is determined rivers with large scale roughness have steep slopes and depths of the same order of magnitude as the bed material size flow resistance depends on the form drag of the roughness elements and their disposition in the channel theoretical considerations show resistance to be a function of reynolds number froude number roughness geometry and channel geometry these processes are examined using the results of flume experiments based on five different roughness beds and a wide range of flows semi empirical analysis supports the theory and allows the development of a theoretical power law resistance equation which accounts for most of the processes a summary of the data is presented for use in other research studies

an example of neotectonism in a continental interior thebes gap midcontinent united states abstract some of the most intense neotectonic activity known in the continental interior of north america has been recently discovered on a fault zone in the thebes gap area missouri and illinois this faulting almost assuredly was accompanied by large earthquakes the zone is located approximately 30 km north of the new madrid seismic zone and consists of complex north northeast to northeast striking steeply dipping faults that have had a long lived history of reactivation throughout most of the phanerozoic geophysical studies by others suggest that the faults are rooted in the deeply buried late proterozoic and early cambrian reelfoot rift system quaternary deposits are cut by at least four episodes of faulting two of which occurred during the holocene the overall style of neotectonic deformation is interpreted as right lateral strike slip faulting at many locations however near surface displacements have stepped from one fault strand to another and produced normal and oblique slip faults in areas of transtension and high angle reverse faults thrust faults and folds in areas of transpression there is evidence of reactivation of some near surface fault segments during the great 1811 1812 new madrid earthquakes quaternary faulting at thebes gap demonstrates that there are additional seismic source zones in the midcontinent u s other than new madrid and that even in the absence of plate margin orogenesis intense neotectonic activity does occur over long time periods along crustal weaknesses in continental interiors

late weichselian and holocene palaeogeography of the rhine meuse delta the netherlands abstract a large number of lithological borehole descriptions 14c dates archaeological artefacts and gradients of palaeochannels were used to reconstruct the holocene development of the rhine meuse delta data were stored in a geographical information system database that enables generation of palaeogeographical maps for any time during the holocene the time resolution of the palaeogeographic reconstruction is about 200 years during the holocene avulsion was an important process resulting in frequent shifts of areas of clastic sedimentation palaeogeographic evolution of the rhine meuse delta is mainly governed by complex interactions among several factors these are 1 location and shape of the late weichselian palaeovalley 2 sea level rise which resulted in back filling of the palaeovalley 3 peat formation which was most extensive in the western part of the back barrier area especially between 4000 and 3000 14c yr bp this more or less fixed the river pattern at that time and resulted in few avulsions 4 neotectonics differential tectonic movements of the peel horst and roer valley graben seem to have influenced river behaviour formation of an asymmetrical meander belt location of avulsion nodes especially from 4500 to 2800 14c yr bp when the rate of sea level rise had decreased after 2800 14c yr bp the sea level rise further decreased and the tectonic influence still may have influenced avulsions but from then on other factors became dominant 5 increased discharge sediment load and or within channel sedimentation after 2800 14c yr bp river meanders of rhine distributaries as well as the single channel of the meuse show remarkable increases in wavelength interpreted as a result of increased bankfull discharge and sediment load increased discharge may initially have been caused by a higher precipitation after 2000 14c yr bp both discharge and sediment load seem to have increased as a result of human influence alternatively decreasing gradients as a result of sea level rise may have caused an increased within channel sedimentation and channel widening which would also lead to increased meander wavelengths 6 composition of the river banks meandering river channels tend to adhere to the sandy margins of the late weichselian palaeovalley and a high channel sinuosity is found in areas where river banks consist of sand 7 marine ingressions e g the ad 1421 st elizabeth s flood caused large scale erosion in the southwestern part of the fluvial deltaic plain 8 human influence since about ad 1100 human influence dominated the palaeogeographic evolution rivers were embanked and dredged meanders were cut off and for the meuse a new distributary canal the bergsche maas was dug in ad 1904 discharge distribution over the various channels is strictly controlled nowadays an unusual feature of the delta is the prolonged existence of the oude rijn channel belt

an event stratigraphy for the last termination in the north atlantic region based on the greenland ice core record a proposal by the intimate group it is suggested that the grip greenland ice core should constitute the stratotype for the last termination based on the oxygen isotope signal in that core a new event stratigraphy spanning the time interval from ca 22 0 to 11 5 k grip yr bp ca 19 0 10 0 k 14 c yr bp is proposed for the north atlantic region this covers the period from the last glacial maximum through termination 1 of the deep ocean record to the pleistocene holocene boundary and encompasses the last glacial late glacial of the traditional northwest european stratigraphy the isotopic record for this period is divided into two stadial episodes greenland stadials 1 gs 1 and 2 gs 2 and two interstadial events greenland interstadials 1 gi 1 and 2 gi 2 in addition gi 1 and gs 2 are further subdivided into shorter episodes the event stratigraphy is equally applicable to ice core marine and terrestrial records and is considered to be a more appropriate classificatory scheme than the terrestrially based radiocarbon dated chronostratigraphy that has been used hitherto 1998 john wiley sons ltd

status of the crustal stress in egypt as inferred from earthquake focal mechanisms and borehole breakouts abstract the recent stress field has been investigated by the analysis of the directions of maximum horizontal stress h as derived from earthquake focal mechanisms and borehole breakouts in egypt the results indicate that in the southern part of the gulf of suez the shallow borehole breakouts stress directions are not consistent with the deep earthquakes focal mechanisms stress directions analysis of 30 borehole breakouts measurements indicate wnw ese alignment of the maximum horizontal stress with a vector mean of 110 14 p e however the earthquake studies including orientation of p axes reflect ene wsw alignment of h with a vector mean of 66 30 thus the stress directions are not constant throughout the crust along the gulf of aqaba the southern part of the dead sea fault the focal mechanism solutions indicate that the maximum horizontal stress is presently nw se oriented corresponding to strike slip mechanism in concert with the geological evidence in northern egypt the nine earthquake focal mechanisms for the nile delta cairo bitter lakes region scatter in orientation varying from ne sw to nw se for h about 45 from these mechanisms indicate nw se 22 wnw ese 22 ene wsw and 11 ne sw alignment of the maximum horizontal stress while in southern egypt it is relatively uniform and aligned to nearly e w direction with a vector mean of 95 3

ages of periods of sand movement in hungary determined through luminescence measurements abstract the late glacial and holocene climatic oscillations in hungary are manifested by changing fluvial and aeolian sand deposition as well as by intercalated soil formations the sand blown territories have special interest since the buried fossil soils provide detailed information about climate and environment changes during the past two decades the time of the sand moving periods was studied exclusively by radiocarbon age determination but by now thanks to the latest investigations these results have been controlled and completed by the thermoluminescence and infrared optically stimulated luminescence dating methods these techniques have been applied to provide a more detailed chronological framework for late pleistocene and holocene sand accumulation periods five aeolian sand accumulation periods can be recognized covering the late glacial and holocene time period at 14 0 2 3 12 0 1 9 9 2 1 7 6 0 0 5 and 0 6 0 07 ka the sand blown formations are intercalated by soil horizons the radiocarbon age estimates provide evidence for late glacial bolling allerod and lower atlantic soil forming periods

shear wave splitting in quaternary sediments neotectonic implications in the central new madrid seismic zone determining the extent and location of surface near surface structural deformation in the new madrid seismic zone nmsz is very important for evaluating earthquake hazards a shallow shear wave splitting experiment located near the crest of the lake county uplift lcu in the central nmsz shows the presence of near surface azimuthal anisotropy believed to be associated with neotectonic deformation a shallow four component data set recorded using a hammer and mass source displayed abundant shallow reflection energy on records made with orthogonal source receiver orientations an indicator of shear wave splitting following rotation of the data matrix by 40 the s1 and s2 sections principal components of the data matrix were aligned with the natural coordinate system at orientations of n35 w and n55 e respectively a dynamic mis tie of 8 ms at a two way traveltime of 375 ms produced an average azimuthal anisotropy of 2 between the target reflector top of quaternary gravel at a depth of 35 m an

sea level and deep water temperature changes derived from benthic foraminifera isotopic records we show that robust regressions can be established between relative sea level rsl data and benthic foraminifera oxygen isotopic ratios from the north atlantic and equatorial pacific ocean over the last climatic cycle we then apply these regressions to long benthic isotopic records retrieved at one north atlantic and one equatorial pacific site to build a composite rsl curve as well as the associated confidence interval over the last four climatic cycles our proposed reconstruction of rsl is in good agreement with the sparse rsl data available prior to the last climatic cycle we compute bottom water temperature changes at the two sites and at one southern indian ocean site taking into account potential variations in north atlantic local deep water 18o our results indicate that a last glacial maximum lgm enrichment of the ocean mean oxygen isotopic ratio of 0 95 is the lowest value compatible with unfrozen deep waters in the southern indian ocean if local deep water 18o did not increase during glacials with respect to present such a value of the lgm mean ocean isotopic enrichment would impose a maximum decrease in local bottom water 18o at the north atlantic site of 0 30 during glacials

on the mechanics of basin formation in the pannonian basin inferences from analogue and numerical modelling abstract we present the results of a thrust fault reactivation study that has been carried out using analogue sandbox and numerical modelling techniques the basement of the pannonian basin is built up of cretaceous nappe piles reactivation of these compressional structures and connected weakness zones is one of the prime agents governing miocene formation and quaternary deformation of the basin system however reactivation on thrust fault planes average dip of ca 30 in normal or transtensional stress regimes is a problematic process in terms of rock mechanics the aim of the investigation was to analyse how the different stress regimes extension or strike slip and the geometrical as well as the mechanical parameters dip and strike of the faults frictional coefficients effect the reactivation potential of pre existing faults results of analogue modelling predict that thrust fault reactivation under pure extension is possible for fault dip angle larger than 45 with normal friction value sand on sand of the fault plane by making the fault plane weaker reactivation is possible down to 35 dip angle these values are confirmed by the results of numerical modelling reactivation in transtensional manner can occur in a broad range of fault dip angle from 35 to 20 and strike angle from 30 to 5 with respect to the direction of compression when keeping the maximum horizontal stress magnitude approximately three times bigger than the vertical or the minimum horizontal stress values our research focussed on two selected study areas in the pannonian basin system the danube basin and the derecske trough in its western and eastern part respectively their miocene tectonic evolution and their fault reactivation pattern show considerable differences the dominance of pure extension in the danube basin vs strike slip faulting transtension in the derecske trough is interpreted as a consequence of their different geodynamic position in the evolving pannonian basin system in addition orientation of the pre existing thrust fault systems with respect to the early to middle miocene paleostress fields had a major influence on reactivation kinematics as part of the collapsing east alpine orogen the area of the danube basin was characterised by elevated topography and increased crustal thickness during the onset of rifting in the pannonian basin consequently an excess of gravitational potential energy resulted in extension v h during early miocene basin formation by the time topography and related crustal thickness variation relaxed middle miocene the stress field had rotated and the minimum horizontal stress axes h became perpendicular to the main strike of the thrusts the high topography and the rotation of h could induce nearly pure extension dip slip faulting along the pre existing low angle thrusts on the contrary the derecske trough was situated near the carpathian subduction belt with lower crustal thickness and no pronounced topography this resulted in much lower v value than in the danube basin moreover the proximity of the retreating subduction slab provided low values of h and the oblique orientation of the paleostress fields with respect to the master faults of the trough this led to the dominance of strike slip faulting in combination with extension and basin subsidence transtension

milankovitch scale multi proxy records from fluvial sediments of the last 2 6 ma pannonian basin hungary abstract the continuous cores of two nearly 500 m deep boreholes cutting pleistocene fluvial sequences in the eastern part of the pannonian basin hungary have been studied magnetostratigraphy indicates that the sediment sequences span the last 2 6 ma without significant hiatuses comparison of systematic variations in magnetic susceptibility with changes in grain size distribution revealed milankovitch scale cyclicity in sedimentation of 40 and 100 kyr cyclicity which also shows a correspondence with the 18o variations of the odp 677 site comparison of pollen and gastropod paleoecological data with the magnetic susceptibility proxies suggests that climate was a major allogenic control on the cyclicity zones of high magnetic susceptibility correspond closely with sandy and coarse silty parts of the borehole successions which largely coincide with pollen and molluscs indicating a warm climate on the contrary zones with low magnetic susceptibility correspond to silts and clays and in most cases coincide with cold climate indicator pollen and molluscs heavy mineral and xrd studies revealed that magnetic susceptibility reflects the absolute amount of detrital fe oxide minerals mostly magnetite variations in the amount of magnetite are related to changes in heavy mineral content which arise primarily from changes in sediment supply to the basin by rivers the depositional model for the pleistocene fluvial sediments suggests that sediment flux increased towards the basin during interglacials due to the increased discharge and transport capacity of the rivers while a decreased sediment supply to the distal parts of the basin occurred during glacials a delay between erosion and storage of weathering products near to the source area and subsequent transportation and re deposition of sediments in the basin interior setting is an important cause of this effect

geochemistry and arsenic behaviour in groundwater resources of the pannonian basin hungary and romania abstract groundwater resources in the pannonian basin hungary romania croatia and serbia are known to contain elevated naturally occurring as published estimates suggest nearly 500 000 people are exposed to levels greater than the eu maximum admissible concentration of 10 g l in their drinking water making it the largest area so affected in europe in this study a variety of groundwaters were collected from romania and hungary to elucidate the general geochemistry and identify processes controlling as behaviour concentrations ranged from so 4 2 reduction containing low as levels so 4 2 ongoing so 4 2 reduction will release s2 removing as from solution either by the formation of as sulfides or from sorption onto fe sulfide phases in methanogenic waters as released by reductive dissolution is not removed from solution and can rise to the high levels observed levels of organic c are thought to be the ultimate control on the redox conditions in these 2 groups high levels of organic c as found in group 1 would quickly exhaust any so 4 2 present in the waters driving the system to methanogenesis and subsequent high levels of as group 2 has much lower concentrations of organic c and so so 4 2 is not exhausted therefore as levels in waters of the pannonian basin are controlled not by release but by retention mechanisms ultimately controlled by levels of toc and so 4 2 in the waters d and 18o analysis showed that groundwaters containing elevated as dated mostly from the last ice age and are sourced from late pliocene to quaternary aquifers the importance of toc and retention capabilities of so 4 2 reduction have only previously been suggested for recent holocene sediments and groundwater most notably those in se asia as these are the most likely to contain the right combination of factors to drive the system to a redox situation leading to high aqueous as concentrations in contrast it is shown here that a much older system containing as bearing fe oxides also has the potential to produce elevated levels of as if the toc is suitable for the microbial population to drive the system to the correct redox situation and so 4 2 is either absent or wholly consumed

reconstruction of a pleistocene meandering river in east hungary by vhr seismic images and its climatic implications abstract the upper 20 30 m of the pleistocene alluvial sequence on the tisza river hungary is investigated by 200 km of vhr single channel seismic sections frequent internal configurations such as 1 bundles of inclined reflections 2 trough shaped converging and 3 horizontal parallel reflections are interpreted respectively as lateral accretion of point bars abandoned channel fills and floodplain deposits the series of 5 8 m thick inclined strata sets occurring at the same depth throughout the area suggest the presence of a meandering river dated to about 43 47 ka in the late pleistocene according to osl data newly recorded quasi 3d seismic profiles reveal that each 1 3 km long inclined series correlates with an individual point bar continuously migrating in the same direction small deviations in the direction of migration are caused by natural wandering of the meander bend morphometric parameters of point bars are used to calculate ancient channel parameters width and depth of 200 500 m and 5 8 m respectively values imply a channel forming discharge of q 400 900 m 3 s these results imply a greater amount of runoff and supply in the basin during mis3 compared to the present day long lasting meandering indicates the role of local factors and a different fluvial environment compared to the commonly anastomosing systems in nw europe our data support the thesis of the three axis drainage system for the basin new evidence is provided for the antecedent existence of a temporally active third trunk river in addition to the ancestors of danube and tisza rivers contrary to the present day two axis drainage pattern