experimental analysis of debris motion due the obstruction from fixed obstacles in tsunami like flow conditions abstract experimental research was conducted focusing on debris motion over a horizontal apron featuring vertical obstacles in the path of the debris propagation the apron was designed as a typical representation of a harbor threatened by an inundating tsunami the experimental setup idealized often complex harbor settings the debris was a scaled down 20 foot shipping container modelled at a 1 in 40 froude length scale offand onshore regions were separated by a vertical quay wall which allowed the incoming elongated solitary wave used to represent the first part of a tsunami to steepen break and propagate over the initially dry surface as a tsunami like bore in the path of propagation a varying number of debris were entrained within the inundating bore over the horizontal apron the entrained debris interacted with regularly spaced vertical obstacles representing infrastructure and houses within the propagation path varying debris and obstacle arrangements were tested to evaluate the effects the obstacles would have on the debris maximum longitudinal displacement and the spreading angle the main conclusion is that the spreading angle of the debris is not as significantly altered by the presence of obstacles on the harbor apron whereas the maximum longitudinal displacement of the debris was significantly affected

seismically generated hydroplastic deformation structures in the late miocene lacustrine deposits of the malatya basin eastern turkey abstract the late miocene succession of continental deposits in the malatya basin eastern anatolia comprises alluvial fan lacustrine and fluvial facies associations this fault bounded basin formed in a tectonically active region notorious for strong earthquakes still today the lacustrine deposits in the northern part of the basin show several isolated horizons of soft sediment deformation including such structures as slump folds load and flame features sand dikes and small scale synsedimentary reverse faults with associated folds there is no direct evidence supporting instabilities due to unequal loading or overloading wave induced cyclical and or impulsive stresses sudden changes in groundwater level or bioturbation capable of producing these deformation structures the soft sediment deformation structures described in the lacustrine deposits are interpreted as having developed as a result of seismic activity taking place along the malatya fault zone based on the tectonic setting of the basin the lateral extent of the soft sediment deformation structures over hundreds of metres their confinement by undeformed layers the presence of complex structures and similarities with structures interpreted as being seismically induced in other areas and those obtained experimentally

origin of limestone conglomerates in the choson supergroup cambro ordovician mid east korea abstract the choson supergroup cambro ordovician of mid east korea consists mainly of shallow marine carbonates and contains a variety of limestone conglomerates these conglomerates are largely comprised of oligomictic rounded lime mudstone clasts of various size and shape equant oval discoidal tabular and irregular and dolomitic shale matrices most clasts are characterized by jigsaw fit mosaic disorganized or edgewise fabric and autoclastic lithology each conglomerate layer is commonly interbedded with limestone dolomitic shale couplets and occasionally underlain by fractured limestone layer capped by calcareous shale limestone conglomerates in the choson supergroup consist of 1 disorganized polymictic conglomerate cd 2 horizontally stratified conglomerate cs 3 mosaic conglomerate cm and 4 disorganized edgewise oligomictic conglomerate cd e these conglomerates are either depositional cd and cs or diagenetic cm and cd e in origin diagenetic conglomerates formed under the conditions of 1 alternating deposition and preservation of carbonate rich and carbonate poor layers and 2 early differential cementation of carbonate rich layers in situ fragmentation may result from brittle fracturing and ductile deformation due to compaction and dewatering enhanced by dissolution processes fluidization is promoted by the overlying impermeable calcareous shale beds and has probably reinforced in situ fragmentation of the underlying limestone beds in situ fragmentation and rounding process is important whereby earlier semiconsolidated portions of limestone are incorporated into the still fluid portion which can be termed autoconglomeration process a synthesis of 145 beds of limestone conglomerates in the choson supergroup suggests that less than about 7 of the conglomerate layers 10 145 are depositional whereas the rest more than 93 135 145 are identified as diagenetic conglomerates the common occurrence of diagenetic conglomerates warrants further study on limestone conglomerates elsewhere in the world

soft sediment deformation structures induced by strong earthquakes in southern siberia and their paleoseismic significance abstract liquefaction induced soft sediment deformation structures ssds formed by earthquakes in southern siberia that were historically mentioned or monitored by instruments are described and analyzed clastic dikes are the most common among all ssds in the epicentral areas of the investigated seismic events they are also the most reliable paleoseismic indicators in regions where cryogenic processes are intense we suggest seven criteria that may be useful to distinguish the seismogenic clastic dikes from non seismogenic ssds in a single outcrop 1 pushed up sedimentary blocks within the dike body 2 regular distorted contacts of a dike with host sediments reflecting cyclic loading during propagation of seismic waves 3 turned up layers of host deposits on contacts with a dike 4 displacement along dike contacts usually in the form of a normal fault caused by subsidence that compensates for the removed sediment 5 a dike structure similar to a diapir 6 filling of a clasic dike with coarser materials than the host sediments and 7 a sediment layer extruded on the surface or between strata similar in composition to the dike in the extruded sandy gravel pebble layer rock fragments show normal grading from large to small clasts in addition to these indicators fractures may indirectly indicate the seismogenic genesis of liquefaction induced ssds due to the close spatial relationship of dikes with the fault structures of the investigated areas they can be used to identify seismogenic fault and the characteristics of dikes lateral gradual changes in the frequency size and type of the deformations can help to determine the epicenter magnitude and the local intensity of the associated earthquakes

diastasis cracks mechanically generated synaeresis like cracks in upper cambrian shallow water oolite and ribbon carbonates upper cambrian limestones and dolostones of western newfoundland canada display conspicuous synsedimentary mud cracks cracks occur in carbonate mudstone interbedded with ooid and peloid grainstone unwashed oolite and ribbon rock lithofacies the traditional interpretation is that these are desiccation cracks the weight of evidence supports an alternative e explanation cracks resulted from the differential mechanical behaviour under stress of stiff mud interlayered with loose ooid peloid sand the processes envisaged to cause such diastasis cracks may be applicabl e to a wide variety of both carbonate and terrigenous clastic deposits composed of interlayered sediments of contrasting material properties and may be a viable alternative to synaeresis

experimental studies of the fluidization of layered sediments and the formation of fluid escape structures experiments demonstrate that fluid escape structures can be produced as a result of unstable fluidization behaviour where a lower base layer of granular material is inhibited from fluidizing by the presence of an overlying non fluidizing top layer before the base layer can fluidize the weight of the overlying material must be balanced and this is accomplished by base layer material pressing against the bottom surface of the confining top layer forming a static layer this static layer allows the top layer to lift away from the base layer which is then free to fluidize a water filled crack forms below the static layer and as this grows instability causes the static layer and top layer to bend and conical voids to form below the antiformal sections rupture occurs at the apex of the water void allowing the underlying water and fluidizing material to burst out through the top layer the fluidized base layer material then flows through the rupture until all of this material except that in the static layer is deposited above the previously overlying layer and a stable fluidization system results the top layer material is bent upwards around the rupture and the resulting pillar type escape structure is preserved if flow then ceases the vigour of the burst out is greatest when the base layer material has a grain size 15 of the top layer material if the base layer grain size is less than 8 of the top layer then base layer material will pass through the top layer pore spaces without forming an escape structure if cohesive material is present escape structures form when a layer of fine grained cohesive material overlies a layer of cohesionless material at low flow rates small pipes with scattered angular bends pierce the top layer and base layer material passes through them the base layer material is ejected on to the top layer and builds up around the mouth of each pipe to form constructional structures sand volcanoes this is in contrast to the cohesionless experiments where the weight of material being deposited on the top layer caused an ejecta filled depression to form around the rupture if flow then ceases both the pipes and the sand volcanoes are preserved at high flow rates where the base layer fluidizes the top cohesive layer becomes fragmented small fragments circulate within the fluidizing base layer and are preserved as floating clasts large fragments sink to the bottom of the fluidizing base layer erosion of the bottom surface of these larger fragments causes this surface to become convex downward the experimentally derived structures are similar to pillar type structures observed in the field and the processes described can be used to investigate the development of these structures fluidization experiments also demonstrate the genesis of dish structures and the cohesive behaviour can be applied to the deformation of these structures after initial formation

soft sediment deformation structures induced by cyclic stress of storm waves in tempestites miocene guadalquivir basin spain the identification of triggering agents for soft sedimentation structures is an enigmatic geological problem mainly seismic induced soft sediment structures have been recognized in ancient sediments rather than those resulting from storm waves we analyse soft sediment deformation structures in upper miocene calcarenitic tempestites of the guadalquivir basin southern spain the most common structures are load casts which vary in height and width from 10 centimetres to several metres the structures are always restricted to a small part of the stratigraphic sections in exclusive association with tempestites the analysed soft deformation structures are interpreted to be the result of liquidization processes chiefly from their inferred depositional environment and subordinately from the deformation style we have devised basic criteria to identify the trigger mechanism in these soft sediment deformation structures the liquefaction was triggered by pore pressure changes induced by cyclic and residual stress of storm waves

spatial variation in carbonate carbon isotopes during the cambrian spice event across the eastern north china platform abstract the cambrian spice steptoean positive carbon isotope excursion event is widely reported from the late miaolingian to the early furongian but recent studies imply that the synchroneity and magnitude of the spice may be controversial in order to test the spatial variation of the spice here we present 367 carbonate 13c data from six outcrop sections across a 700 km transect along the eastern north china platform the spice is present in all the studied sections but showing different features regarding the duration and magnitude an abrupt increase in 13c from 1 5 to 3 5 occurs in three shandong sections with maximum value present only in a thin 0 5 1 2 m thick transgressive lag deposit crudely wave stratified bioclastic grainstone in contrast the 13c record of the baijiashan and shashan sections in the liaoning region displays a gradual increase 20 m thick from 1 5 to the maximum value of 4 7 both facies analysis and trilobite collections suggest that the spatial variation of the spice in the north china platform most likely resulted from missing of sedimentary record with high 13c values in the shandong sections as a result of erosion and non deposition during sea level lowstand a possible coeval hiatus prior to the sauk iii transgression in the laurentian basins further high resolution integrated studies of sedimentology biostratigraphy and sedimentary geochemistry on the spice event are required to better understand its nature

slump sheets as a record of regional tectonics and paleogeographic changes in south china abstract slumps of various scales are recognized in the late katian late ordovician mixed carbonate and siliciclastic slope successions in the changshan area western zhejiang province south china in order to understand their deformational processes triggering mechanisms paleo slope orientation and geological implications a detailed sedimentological study was carried out on four outcrop sections in the southern changshan the putangkou zhoutang and shikeng sections we recognized three slumping episodes ca 3 5 m 11 m and 73 m in thickness in stratigraphically ascending order and co occurred debris flows at the sanqushan section 11 5 km north of changshan thirteen slump units each being tens of cm to 6 m in thickness are recognized facies analyses and diagenetic characteristics of these slumps and their internal deformation structures suggest that they formed as a result of plastic and brittle deformation and liquefaction and fluidization during slumping the rip up blocks cracks and ruptured beds in the slumps of southern changshan indicate extensional features whereas recumbent and disharmonic folds in the slumps of northern changshan represent compressional features these spatially different features suggest that the slumps may have been generated on a paleo slope dipping generally to the north the case study of slumps and debris flows from the putangkou section indicates a significant mass flow transition from a slumped mass into debris flow deposits autogenic triggering mechanisms of these slumps e g rapid deposition storm wave loading and tidal shear are ruled out by the results of facies analysis instead the slumps might have been triggered by relative sea level changes or tectonically induced progressively steepening of the slope which is likely related to the contemporaneous kwangsian orogeny

abraded sand volcanoes as a tool for recognizing paleo earthquakes with examples from the cisuralian talchir formation near angul orissa eastern india abstract one of the bedding planes of a sandstone unit belonging to the cisuralian talchir formation is well exposed along the nandir jhor river in eastern india it shows a few dozens of circular structures commonly with diameters of a few decimetres a concentration is found in an area of some 50 m 2 where 12 well developed specimens occur the structures are interpreted as abraded sand volcanoes which interpretation is supported by the occurrence on the same bedding plane of a sand volcano with a diameter of over a meter the concentrated structures thus represent a sand volcano field a phenomenon that has not been recognized earlier in the pre holocene geological record but that in recent times seems always to be related to an earthquake the structures described here might therefore help to recognize earthquakes that occurred in the geological past

particle dynamics the continuum of bedrock to alluvial river segments abstract particle dynamics refers to production erosion transport and storage of particulate material including mineral sediment and organic matter particle dynamics differ significantly between the end members of bedrock and alluvial river segments and between alluvial river segments with different grain size distributions bedrock segments are supply limited and resistant to change with relatively slow linear adjustments and predominantly erosion and transport particle dynamics in alluvial segments in contrast are transport limited and dominated by storage of mineral sediment and production of organic matter alluvial segments are resilient to change with relatively rapid multidirectional adjustments and stronger internal influences because of feedbacks between particles and biota bedrock segments are the governors of erosion within a river network whereas alluvial segments are the biogeochemical reactors fundamental research questions for both types of river segments center on particle dynamics which limit network scale incision in response to base level fall bedrock segments and habitat biogeochemical reactions and biomass production alluvial segments these characterizations illuminate how the spatial arrangement of bedrock and alluvial segments within a river network influence network scale resistance and resilience to external changes in relative base level climate and human activities

distance of movement of coarse particles in gravel bed streams distributions of distance of bedload particle movement were examined in two gravel bed streams using several hundred magnetically tagged cobbles and pebbles the compound poisson model of einstein hubbell sayre and a simple gamma function model were compared with observed distributions of moved particles and of all particles both models fit the data reasonably well for small mean displacements but notable misfits occurred in an event with large mean displacement when mean particle travel distance approaches the scale of bar spacing trapping in the bars interrupts particle progress and the dispersion process the data remain very noisy so definitive discrimination of suitable models will require trials with more than 103 particles

nonintrusive spatiotemporal smart debris tracking in turbulent flows with application to debris laden tsunami inundation abstractflood disasters such as dam breaks and surges from extreme hurricanes or tsunamis entrain and transport substantial amounts of submerged or floating debris understanding of motion and spatiotemporal distribution of debris entrained by a flood is thus of great importance to hydraulic coastal and structural engineers the displacement of debris to a location where it may eventually impact critical infrastructure requires scientific attention at the laboratory scale first in this context the design and application of a novel smart debris system utilizing off the shelf components is presented and discussed the system tracks the spatial location and orientation of a multitude of debris specimens and it proposes an accurate tool to assess their individual trajectory velocity and momentum in a laboratory environment contrary to the traditional camera based approach of video tracking which often fails once objects are submerged the proposed smart debris system delivers six degree of freedom 6d

eemian interglacial reconstructed from a greenland folded ice core efforts to extract a greenland ice core with a complete record of the eemian interglacial 130 000 to 115 000 years ago have until now been unsuccessful the response of the greenland ice sheet to the warmer than present climate of the eemian has thus remained unclear here we present the new north greenland eemian ice drilling neem ice core and show only a modest ice sheet response to the strong warming in the early eemian we reconstructed the eemian record from folded ice using globally homogeneous parameters known from dated greenland and antarctic ice core records on the basis of water stable isotopes neem surface temperatures after the onset of the eemian 126 000 years ago peaked at 8 4 degrees celsius above the mean of the past millennium followed by a gradual cooling that was probably driven by the decreasing summer insolation between 128 000 and 122 000 years ago the thickness of the northwest greenland ice sheet decreased by 400 250 metres reaching surface elevations 122 000 years ago of 130 300 metres lower than the present extensive surface melt occurred at the neem site during the eemian a phenomenon witnessed when melt layers formed again at neem during the exceptional heat of july 2012 with additional warming surface melt might become more common in the future

soft sediment deformation structures in cambrian siliciclastic and carbonate storm deposits shandong province china differential liquefaction and fluidization triggered by storm wave loading abstract this paper focuses on soft sediment deformation structures ssds in both siliciclastic and carbonate storm deposits of the cambrian mantou and chaomidian formations shandong province china in order to understand their deformation mechanisms and possible triggers siliciclastic ssds e g sand volcanoes and pillows and carbonate ssds e g sedimentary dykes grainstone matrix breccias deformed cross beddings and marlstone matrix breccias occur exclusively in hummocky cross stratified fine sandstone and peloidal grainstone respectively the siliciclastic ssds formed in porous and permeable surface sediment whereas the carbonate ssds formed under shallow burial conditions when early marine cementation prevailed the various deformation structures resulted mainly from differences between siliciclastic and carbonate sediment conditions and resulting deformation mechanisms sand volcanoes formed by upward extrusion of over pressured fluidized sandy sediment whereas sand pillows resulted from upward injection of lower density muddy sediment into overlying liquefied sandy sediment sedimentary dykes and grainstone matrix limestone breccias formed as a result of differential liquefaction and fluidization of heterogeneously cemented carbonate sediment whereas deformed cross beddings and marlstone matrix limestone breccias developed by the thixotropic liquidization and injection of clayey sediment and further disruption of thin peloidal layers sedimentary facies analysis and analysis of the physical processes indicate that the ssds were most likely caused by cyclic loading of storm waves

tectonic and sedimentary evolution of the korean peninsula a review and new view abstract this review focuses on the tectonics and sedimentation of major sedimentary basins and orogenic belts late proterozoic neogene in the korean peninsula the korean peninsula is part of the amuria plate and represents an important link between continental blocks of north and south china and the island arcs of japan the basement rocks exposed in the kyonggi and yongnam massifs consist of 2 7 to 1 1 ga high grade gneiss and schist these massifs are separated by the okchon fold belt which comprises metasedimentary rocks and bimodal meta volcanic rocks the stratigraphy of the okchon group is unclear at present the okchon basin was probably initiated as an intraplate rift prior to the late proterozoic the hwanggangri formation clast bearing phyllite most likely represents deposition by subaqueous debris flows in slope environments of an enclosed basin the stratigraphic relationship between the okchon group and the choson supergroup cambro ordovician of the taebaeksan basin is poorly constrained the choson supergroup unconformably overlies the yongnam massif and consists mainly of carbonate sequence that formed mostly in shallow marine and tidal environments reflecting numerous sea level fluctuations the sequence is disconformably overlain by siliciclastic sequence of pyongan supergroup carboniferous triassic which formed most likely in shallow marine deltaic and fluvial environments the imjingang belt is an east trending fold and thrust zone and consists of metasedimentary rocks and volcaniclastics devonian carboniferous underlain unconformably by proterozoic basement rocks late proterozoic amphibolites of oceanic affinity were metamorphosed at about 8 13 kbar and 630 740 c during the late permian to the early triassic the south vergent contraction and top down to the north normal faulting are suggestive of a suture belt between the north china block sino korea craton and the south china block yangtze craton an extension of sulu belt across the yellow sea entire peninsula experienced strong deformation and metamorphism during the suturing event namely songrim orogeny during this orogenic event the kyonggi massif and the okchon basin accreted to the yongnam massif and taebaeksan basin along the south korean tectonic line running northeast southwest a series of northward trending thrust formed along the boundary zone to the east kaktong and kongsuwon thrusts and others piggyback basins locally developed along the thrust faults forming the taedong group the crustal deformation resumed in the early to late jurassic daebo event under contractional setting dextral ductile shearing associated with thrusting and folding continued in the mid southern part of the peninsula it was due to orthogonal northwestward subduction of the izanagi plate under the asian continent the yongnam massif experienced continuous dextral offset along the honam shear zone in the early cretaceous the izanagi plate began to subduct northward and caused formation of strike slip basins in retroarc setting i e kyongsang basin in the southeastern part and a number of small scale basins in the mid southwestern part of the peninsula small scale alluvial fans and fluvial channel networks formed in the basin margin and were transitional to ephemeral lacustrine systems under semiarid to arid conditions extensive intrusion of granitoids occurred from triassic to early tertiary with a gap between 160 and 100 ma representing continental magmatic arc in the tertiary the southeastern margin of the korean peninsula experienced back arc opening pull apart basins formed in the miocene bounded by the yangsan and hupo faults the yonil group sedimentary fill of the pohang basin comprises more than 1 km thick siliciclastic sequence which represents deposition in fan delta systems on the hanging wall of the yangsan fault thick more than 10 km thick sediments in the ulleung basin margin were deformed in the late miocene due to the northward movement of kyushu block quarternary volcanic events in cheju island represent intraplate hot spots

bedload entrainment travel lengths step lengths rest periods studied with passive iron magnetic and active radio tracer techniques this paper reports results from bedload transport investigations with active radio and passive iron magnetic tracers in the lainbach a step pool mountain river in bavaria southern germany the spatial distributions of the iron tracers after flood events can be best described by exponential or gamma distributions there is some indication of a tendency of size selective transport of the iron tracers but there is also a considerable amount of scatter in the correlations between weight size and travel length owing to the masking influence of other variables such as the shape of the particles and different positions in the river bed the experiments with artificial magnetic tracers showed that elongated pebbles rods had the longest mean transport distance platy ones discs remained relatively close to the starting points the particles from the pool showed the greatest transport lengths and a 100 per cent chance of being eroded the pebble transmitter system petsy consists of transmitters implanted into individual pebbles a computerized receiver a stationary antenna system with an antenna switchboard and a data logging system the particles do not move continuously but in a series of transport steps and non movement intervals a single value for a given size class is not adequate to describe the critical conditions of entrainment under natural circumstances a probability approach is much more suitable the critical unit discharges total discharge divided by active channel width along the measuring reach are dependent on river bed morphology in the steps bedload needs higher unit discharges to be entrained once entrained the transport of bedload is stochastic in nature and the single particle transport is controlled by the step lengths and the duration of rest periods the distributions of both parameters can be approximated by exponential functions applying the stochastic concept proposed by einstein the mean values of the random variables step length and duration of rest period measured with the petsy technique were used for the simulation of spatial distributions of bedload particles from point sources more field and laboratory data are needed to include varying flow and roughness conditions with tracers representing different particle characteristics

limestone pseudoconglomerates in the late cambrian gushan and chaomidian formations shandong province china soft sediment deformation induced by storm wave loading this paper focuses on the formative processes of limestone pseudoconglomerates in the gushan and chaomidian formations late cambrian of the north china platform shandong province china the gushan and chaomidian formations consist mainly of limestone and shale marlstone interlayers wackestone to packstone grainstone and microbialite as well as numerous limestone conglomerates seventy three beds of limestone pseudoconglomerate in the gushan and chaomidian formations were analysed based on clast and matrix compositions internal fabric sedimentary structures and bed geometry these pseudoconglomerates are characterized by oligomictic to polymictic limestone clasts of various shapes i e flat to undulatory disc blade and sheet marlstone and or grainstone matrix and various internal fabrics i e intact thrusted edgewise and disorganized as well as transitional boundaries limestone pseudoconglomerates formed as a result of soft sediment deformation of carbonate and argillaceous interlayers at a shallow burial depth differential early cementation of carbonate and argillaceous sediments provided the requisite conditions for the formation of pseudoconglomerates initial deformation i e burial fragmentation liquefaction and injection and subsequent mobilization and disruption of fragmented clasts are two important processes for the formation of pseudoconglomerates burial fragmentation resulted from mechanical rupture of cohesive carbonate mud whereas subsequent mobilization of fragmented clasts was due to the injection of fluid materials liquefied carbonate sand and water saturated argillaceous mud under increased stress storm wave loading was the most probable deformation mechanism as an external triggering force subsequent re orientation and rounding of clasts were probably prolonged under normal compactional stress eventually disrupted clasts along with matrix materials were transformed into pseudoconglomerates by progressive lithification soft sediment deformation is prevalent in alternate layers of limestone and mud marl stone and or grainstone regardless of their depositional environments

a reconciled estimate of ice sheet mass balance we combined an ensemble of satellite altimetry interferometry and gravimetry data sets using common geographical regions time intervals and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of earth s polar ice sheets we find that there is good agreement between different satellite methods especially in greenland and west antarctica and that combining satellite data sets leads to greater certainty between 1992 and 2011 the ice sheets of greenland east antarctica west antarctica and the antarctic peninsula changed in mass by 142 49 14 43 65 26 and 20 14 gigatonnes year 1 respectively since 1992 the polar ice sheets have contributed on average 0 59 0 20 millimeter year 1 to the rate of global sea level rise

geomorphic controls on contaminant distribution along an ephemeral stream sediment borne contamination in a watershed can be highly variable as a result of uvial processes operating over a range of time scales this study presents a detailed analysis of the distribution of one contaminant along an ephemeral stream after 55 years of sediment transport deposition and exchange by ash oods wastewater containing plutonium was discharged into the pueblo canyon watershed from 1945 until 1964 and plutonium concentrations in uvial deposits vary over ve orders of magnitude these variations can be attributed to three primary factors time since contaminant releases particle size sorting and mixing of sediment from different sources the highest concentrations occur in ne grained sediment deposits near the source that date to the period of ef uent releases and concentrations are lower in younger deposits in coarser grained deposits and in deposits farther downstream the spatial distribution of plutonium is strongly affected by longitudinal variations in the size of sediment deposits of different age a major aggradation degradation cycle in the lower canyon overlapped with the period of active ef uent releases and a signi cant portion of the total plutonium inventory is contained within large coarse grained deposits below ll terraces that post date 1945 the spatial pattern of contamination is thus determined by the speci c geomorphic history of the watershed in addition to processes of mixing and sorting during transport that occur in all uvial systems copyright 2004 john wiley sons ltd

radio tracking gravel particles in a large braided river in new zealand a field test of the stochastic theory of bed load transport proposed by einstein hans a einstein initiated a probabilistic approach to modelling sediment transport in rivers his formulae were based on theory and were stimulated by laboratory investigations the theory assumes that bed load movement occurs in individual steps of rolling sliding or saltation and rest periods so far very few attempts have been made to measure stochastic elements in nature for the first time this paper presents results of radio tracing the travel path of individual particles in a large braided gravel bed river the waimakariri river of new zealand as proposed by einstein it was found that rest periods can be modelled by an exponential distribution but particle step lengths are better represented by a gamma distribution einstein assumed an average travel distance of 100 grain diameters for any bed load particle between consecutive points of deposition but larger values of 6 7 m or 150 grain diameters and 6 1 m or 120 grain diameters were measured for two test particle sizes together with other available large scale field data a dependence of the mean step length on particle diameter relative to the d50 of the bed surface was found during small floods the time used for movement represents only 2 7 of the total time from erosion to deposition the increase in percentage of time being used for transport means that it then has to be regarded in stochastic transport models tracing the flow path of bed load particles between erosion and deposition sites is a step towards explaining the interactions between sediment transport and river morphology copyright 2001 john wiley sons ltd

introduction to special section on stochastic transport and emergent scaling on earth s surface rethinking geomorphic transport stochastic theories broad scales of motion and nonlocality 1 in many geomorphic transport systems the time and length scales of motion vary widely particles can be trapped for both short and long periods of time and they can travel large or small distances in very short intervals of time to model such systems we need fresh conceptual and mathematical formalisms the goal of this collection of papers is to challenge existing thinking in geomorphic transport by putting forward new ideas and theories for environmental fluxes from particle transport in a single stream to landslide debris mobilization sediment and water transport on hillslopes dynamic transport on river networks and interpretation of sedimentary deposits over geologic time advanced stochastic theories of transport are proposed the notion of nonlocal flux is introduced and fractional advection diffusion equations are explored as possible models of geomorphic transport

calcite precipitation induced by bacillus cereus mrr2 cultured at different ca2 concentrations further insights into biotic and abiotic calcite abstract a key problem of how to distinguish between biotic and abiotic carbonate minerals in nature and or in the laboratory has confused researchers for some time although numerous studies have been performed to explore the formation mechanism and the unique characteristics of biotic minerals the issue needs to be studied further here biotic calcite precipitation was induced by the microorganism bacillus cereus mrr2 genbank ky810857 while organogenic and inorganogenic calcite was investigated in parallel the results indicate that carbonic anhydrase ca a common enzyme of bacteria promoted carbon dioxide hydration to release hco3 and co32 in the process of calcite precipitation the ph increased from 7 2 to 8 9 as a result of the combination effect of the released ammonia by b cereus mrr2 and the hco3 and co32 ions originating from the ca reaction glutamic acid is the most abundant amino acid in the extracellular polymeric substances of the bacteria and its free carboxyl ions with a large number of negative charges in the alkaline environment facilitated the adsorption of calcium ions the biotic calcite has a series of unique characteristics different from the organogenic and inorganogenic calcites such as particular morphologies p element composition and a variety of organic functional groups intracellular amorphous nanospheres without any crystal structure are also recorded stable carbon isotope analyses show that the biotic calcite 20 9 has more negative 13c values than the organogenic calcite 15 6 and inorganogenic calcite 11 7 indicating that microbial activity strongly affected the carbon isotope composition of biotic calcite more importantly the crystallinity and activation energy of the biotic calcite are clearly higher than those of organogenic calcite suggesting that the thermal stability of biotic calcite is much higher thus this study provides important insights into understanding the mechanisms of microbial biomineralization and the processes of biotic calcite formation especially the roles microbes played in mineral nucleation and growth as well as the unique characteristics of the resulting minerals this study may provide useful evidence for further recognizing biotic and abiotic calcite in the geological record

morphologically based model of bed load transport capacity in a headwater stream 1 field measurements of channel and bed material properties are used to develop a network based model of bed load transport capacity in halfmoon creek a high gradient stream in the rocky mountains of colorado the formerly glaciated watershed contains self formed reaches that are generally disconnected from hillslopes and major sediment perturbations strung together by a sequence of bedrock and cascade channels measurements of channel geometry slope and bed sediment texture surface and substrate were taken in 27 reaches with gradients ranging from 0 6 to 6 to examine interactions among key variables affecting bed load transport the analysis shows that the grain size distribution of the substrate is relatively uniform throughout the basin however the distinction between surface and substrate texture varies systematically with channel gradient and shear stress reaches with high shear stress are characterized by coarse surface layers with a high threshold for transport limiting the mobility of the sediment supplied in reaches with lower gradient and shear stress the difference between surface and substrate texture is less increasing both the frequency of transport and the mobility of the bed load while it might appear that the steeper reaches of halfmoon creek have a high capacity for carrying fine medium gravel the relative mobility of these sizes is affected by the presence of very coarse sediment on the bed surface as a result modeled estimates of bed load transport rate indicate that average annual bed load sediment yields increase downstream nearly linearly with discharge suggesting a simple scaling of bed load transport capacity with discharge and drainage area

grounding line retreat of the west antarctic ice sheet from inner pine island bay ice loss from the marine based potentially unstable west antarctic ice sheet wais contributes to current sea level rise and may raise sea level by 3 3 m or even 5 m in the future over the past few decades glaciers draining the wais into the amundsen sea embayment ase have shown accelerated ice flow rapid thinning and fast retreat of the grounding line gl however the long term context of this ice loss is poorly constrained limiting our ability to accurately predict future wais behavior here we present a new chronology for wais retreat from the inner continental shelf of the eastern ase based on radiocarbon dates from three marine sediment cores the ages document a retreat of the gl to within 100 km of its modern position before ca 10 000 calibrated cal yr b p this early deglaciation is consistent with ages for gl retreat from the western ase our new data demonstrate that in contrast to the ross sea wais retreat from the ase shelf was largely complete by the start of the holocene our results further suggest either slow gl retreat from the inner ase shelf throughout the holocene or that any episodes of fast gl retreat must have been short lived thus today s rapid retreat may be exceptional during the holocene and may originate in recent changes in regional climate ocean circulation or ice sheet dynamics

using passive integrated transponder pit tags to investigate sediment transport in gravel bed rivers abstract in gravel bed rivers measuring the displacement of individual grains by fluid flow is essential in order to understand sediment transport processes and to investigate changes in channel morphology we present preliminary results of a new technique that traces pebble movements by inserting 23 mm passive integrated transponders pit into individual clasts because each pit has its own signal identification this technique is ideal for tracking the individual movements of episodically transported particles in gravel bed rivers two hundred and four tagged particles were inserted into a 130 m long reach of a gravel bed river with a 2 slope and a bed material with a d50 of 70 mm the b axis size of the tagged particles ranged from 40 mm to 250 mm recovery percentages after two competent floods were 96 and 87 clearly demonstrating the effectiveness of this new technique buried particles can be recovered at a depth of 0 25 m pit tags are also suited for long term studies over several years

funnel shaped breccia filled clastic dykes in the late cambrian chaomidian formation shandong province china abstract some examples of a funnel shaped structure filled with both angular and rounded clasts occur in a peloidal grainstone bed of the chaomidian formation late cambrian in the jiulongshan area shandong province china the clasts consist of peloidal grainstone which is the same as that of the walls of the funnels the structures are interpreted as dykes formed by upward escape of pore water and or fluidized sediment through a narrow conduit which was gradually widened by the force of the intruding fluid sediment the erosional capacity of the pressurized fluid sediment mixture consequently diminished upwards which explains the gradual decrease in intensity of fragmentation from the adjoining walls in this direction

a field experiment on the development of sedimentary structures in a gravel bed river in gravel bed rivers bed sedimentary structures exert a significant influence on the stability of the bed particle motion and stream dynamics a detailed description of the development of sedimentary structures is essential to define the overall activity of sediment transport this paper aims to improve our understanding of the dynamics of sedimentary structures at the reach scale using a field approach the objectives of the study are 1 to describe the processes of sedimentary structures development from a manipulated bed surface and 2 to show the effect of keystones on the development of the sedimentary structures by monitoring the displacement of individual tagged particles we investigated the dynamics of sedimentary structures in three 15 m long reaches of a small gravel bed river characterized by moderate slope and high relative roughness the bed material is composed of a range of gravel sizes with sparse boulders that remain immobile during most flows we have disrupted the bed surface material of the first reach to create a disorganized bed surface two reaches where the bed material remained undisturbed were used as control sections detailed topographic maps and passive transponders were used to describe the formation processes of sedimentary structures the initial manipulations of the bed led to a more fragmented surface in the experimental section however sedimentary structures developed very quickly with an equilibrium bed surface developing after only two sediment transport events of low magnitude discharge this rapid adjustment of the bed is associated with the development of key sedimentary structures anchored by the large boulders at the reach scale these structures increased the probability of congested areas in the displacement of bed material in both control sections sedimentary structures were maintained during the experiment copyright 2007 john wiley sons ltd

observations on the movement of coarse gravel using implanted motion sensing radio transmitters motion sensing radio transmitters were implanted in cobbles 72 92 mm diameter and placed in a stream in south west idaho for 43 days during a snowmelt period the radios transmit different pulse rates depending on whether the rocks are at rest or in motion every 30 s a datalogger samples the receiver and records the pulse rate of the transmitters such information can be used to assess numerous properties of particle transport that are beyond the capabilities of conventional tracking methods conclusions include i rocks are more likely to move on rising hydrograph limbs than on falling hydrograph limbs ii the average shields parameter is 0 046 iii rocks move only a fraction of the time between initial and final motion during an event iv the distributions of motion and rest periods are best modeled by gamma functions rather than exponential but the distributions approach exponential as the tails are trimmed copyright 2004 john wiley sons ltd

an extensive erosion surface of a strongly deformed limestone bed in the gushan and chaomidian formations late middle cambrian to furongian shandong province china sequence stratigraphic implications abstract in order to understand sequence development and sea level fluctuations during the late middle cambrian to early furongian on the north china epeiric platform the present study focuses on a unique subtle erosion surface of an extensive approx 100 km strongly deformed limestone bed in the uppermost part of the gushan formation shandong province china the gushan formation and the overlying chaomidian formation consist mainly of shales and a variety of carbonates that were deposited in subtidal environments e g deep subtidal shallow subtidal shoreface shoal subtidal microbial flat and restricted platform interior three third order depositional sequences s1 3 are identified each of which comprises a thin transgressive systems tract tst and a relatively thick highstand systems tract hst each sequence is bounded by a drowning unconformity sb1 a subaerial unconformity sb2 or a surface of submarine erosion sb3 the upper sequence boundary sb2 of sequence 1 s1 is represented by a subtle erosion surface of an extensive deformed limestone bed with a wide variety of soft sediment deformation structures e g lime mudstone breccias chaotic wacke packstone laminae and fragments homogenized oolites and clastic dykes and is overlain by small sporadic microbial buildups and an extensive bioclastic grainstone bed the deformed limestone was formed during early diagenesis by differential deformation processes brecciation liquefaction fluidization and injection which were most likely induced by pore water overpressure during the period of rapid sea level fall despite the lack of subaerial exposure features e g paleokarst paleosol etc the characteristics of the erosion surface cutting well lithified sediment below the missing of a significant geological record the prochuangia biozone and the worldwide correlatable positive carbon isotope excursion collectively indicate that the erosion surface developed under conditions of subaerial exposure after contemporaneous marine cementation of the deformed sediment the missing of the prochuangia biozone is most likely due to non deposition at a subaerial hiatal surface the erosion surface was submerged as a result of subsequent rise in sea level where sporadic microbial buildups formed under suitable conditions freshly deposited winnowed shell dominated transgressive lag deposits containing chuangia trilobite fragments brachiopod shells and abundant glauconite grains formed with continued rise in sea level which became in turn overlain by shale dominated facies the unique combination of the subtle erosion surface sensu stricto a subaerial unconformity and the underlying deformed limestone bed provides an important criterion for recognizing the subtle changes in relative sea level on shallow epeiric platforms

origin of the vertically orientated clasts in brecciated shallow marine limestones of the chaomidian formation furongian shandong province china numerous shallow marine limestone layers of the furongian late cambrian chaomidian formation in the jiulongshan section shandong province china are breccias some of these breccias show abundant vertical to subvertical clasts typically these clasts end abruptly at the contact plane with the overlying deposit either abutting the overlying sedimentary bed or via an erosional plane that truncates the clasts a few exposures show concentrations of clasts that must have been uplifted to the extent that they transgressed the then sedimentary surface or possibly penetrated the overlying sediment which in this case consists of muds or marls the clasts tend to show clusters with respect to the enclosing fabric all clasts are parallel to each other in a specific cluster while the various clusters may show different orientations of the clasts it is deduced that both the exceptional position and the exceptional orientation of the clasts must be ascribed to the upward movement of the clasts under the influence of pore water escaping under high pressure through fluidized sediment

transport trajectories of smart pebbles on an artificial coarse grained beach at marina di pisa italy implications for beach morphodynamics abstract in this paper transport pathways for coarse sediments were studied on an artificial pebble beach located at marina di pisa tuscany italy radio frequency identification rfid technology was used to trace the pebbles the rfid technique is an inexpensive and reliable methodology that is used to address sediment displacement along the coastline the use of low frequency radio signals 125 khz enabled the detection of the marked pebbles within a range of 40 cm on the underwater and subaerial portions of the beach about one hundred pebbles were sampled on the beach and paired with passive transponders the tracers were released along a series of cross shore transects march 2009 the pebbles were injected on the fair weather berm on the swash zone and on the step crest along each transect the recovery campaign was carried out in may 2009 fifty three pebbles were detected this number is rather high given the intensity of the three storms that hit the coast during the period of the experiment and the significant reworking that this beach is subjected to even under fair weather conditions the analysis of the tracer pathways highlighted twofold convergent longshore movement on the beach the trajectories indicated that the longshore movement dominated the cross shore movement but there was no prevailing transport direction to explore the morphology of the sea bottom fronting the beach a topographic survey was carried out using an echo sounder the survey showed the presence of two distinct shoals 20 m off the coastline that are responsible for the resulting coarse sediment transport these results confirm that even mild sea bottom irregularities may significantly affect sediment transport dynamics along a beach suggesting that accurate planning for defense schemes such as artificial coarse replenishment must begin with an in depth knowledge of the morphology of the sea floor such information may increase the durability and or the efficiency of the intervention

sequence sequence stratigraphy sea level changes and depositional systems in the cambro ordovician of the north china carbonate platform abstract the cambro ordovician strata in north china were deposited over a very extensive craton extending some 1500 km east west and 1000 km north south the dominantly shallow water carbonate succession reaches up to 2000 m in thickness and two megasequences transgressive regressive cycles can be distinguished lower cambrian through lower ordovician strata and middle through upper ordovician strata separated by a major palaeokarst the first megasequence consists of nine sequences which are generally 50 150 m in thickness the lower cambrian sediments consist of phosphorites and phosphatic sandstones deposited during the flooding of the craton carbonates mudrocks and evaporites were deposited in the early cambrian under an arid climate laying the foundation for the subsequent long period of shallow water carbonate deposition which lasted some 70 m y the middle and lower upper cambrian sequences consist predominantly of mudrocks and storm deposits tempestites in the lower part and oolitic grainstones and tidal flat lime mudstones in the upper part these represent outer mid and mid inner ramp depositional systems respectively of the transgressive and highstand systems tracts these sequences have strong similarities with the grand cycles in the cambro ordovician successions of north america in the upper cambrian there is a distinctive unit of glauconitic purple red mudstone several metres thick which is interpreted as the deposits of the maximum flooding of the first megasequence in the upper cambrian there was a phase of tilting of the north china carbonate platform to the north and storm deposits especially intraclastic conglomerates and hummocky cross stratified grainstones packstones were very common at this time also common in upper middle and lower upper cambrian strata are stromatolitic thrombolitic bioherms several metres in diameter the upper upper cambrian through lower ordovician strata are dominantly fine grained limestones and dolomites deposited in shallow subtidal and inter to supra tidal environments on a low energy epeiric sea platform this part of the succession is the regressive part of the first megasequence so that overall the platform shows an evolution from platform initiation to platform foundation to a ramp depositional system and then an extensive epeiric platform on a small scale the succession is composed of metre scale shallowing upward cycles parasequences arranged into cycle sets of 10 30 m thick the middle upper ordovician megasequence consists mostly of shallow water carbonates with several thick evaporite units minor palaeokarsts and palaeosoils separate the sequences which are composed of metre scale cycles regional uplift affected the north china platform in the ordovician and sedimentation did not resume until the carboniferous there is a good correlation of the two transgressive regressive megasequences described here with the global 2nd order relative sea level curve for the cambro ordovician

early cretaceous slumps and turbidites with peculiar soft sediment deformation structures on lingshan island qingdao china indicating a tensional tectonic regime abstract some sections on lingshan island in the yellow sea close to the city of qingdao show the early cretaceous lingshandao formation the exposed succession consists mainly of turbidites some of which show uncommon soft sediment deformation structures and contains well developed large scale slumps that consist of sets of turbidites the sediments were deposited as part of lobes of turbidites and hyperpycnites deposits of flood generated sediment laden bottom currents derived from an estuary in a deep sea environment that formed part of an inter arc basin with a tensional tectonic regime some of the slumps have dimensions of the order of metres to tens of metres they consist of the turbidites that build most of the succession the soft sediment deformation structures in the turbidites represent a wide variety of types most of which are common in subaqueous environments with a high accumulation rate the most interesting are however structures that indicate active tectonic tension these structures are boudins which are present with two subtypes the most common are pinch and swell structures sometimes leading to isolated parts of the affected sandy layer enveloped by shales of the under and overlying shale layers the second type consists of domino boudins which have as far as we are aware of not earlier been described from sediments that were still unlithified during their formation the presence of the boudins and associated structures which indicate synsedimentary stretching related to an extensional tectonic setting form an additional argument in the long lasting debate about the question of whether a compressional or an extensional tectonic regime dominated in the area during the early cretaceous

soft sediment deformation structures in the mio pliocene misaki formation within alternating deep sea clays and volcanic ashes miura peninsula japan abstract the mio pliocene misaki formation of the miura group miura peninsula japan shows an extremely wide variety of soft sediment deformation structures the most common deformation structures are load casts and associated flame structures dish and pillar structures synsedimentary faults multilobated convolutions chaotic deformation structures sedimentary veins and dykes and large scale slides and slump scars the formation which accumulated in a deep sea environment 2000 3000 m is well exposed in and around jogashima it consists of relative thin commonly dm scale alternations of deep marine fine grained sediments and volcanic ejecta that are as a rule coarse grained since the formation represents fore arc deposits of the izu bonin and the honsu arc collision zone it might be expected that tectonic activity also played a role as a trigger of the soft sediment deformation structures that abound in these sediments this is indicated indeed by the abundance of soft sediment deformations over large lateral distances that occur in numerous beds that are sandwiched between undeformed beds on the basis of their characteristics and the geological context these layers can be explained satisfactorily only by assuming deformation triggered by seismicity which must be related to the izu bonin and honsu arc collision the layers thus form deep marine seismites

central west antarctica among the most rapidly warming regions on earth the west antarctic ice sheet is contributing to sea level rise but temperature trends in the region have remained uncertain a complete temperature record for byrd station in central west antarctica spanning from 1958 to 2010 establishes west antarctica as one of the fastest warming regions globally

frequency and magnitude of bedload transport in a mountain river magnitude and frequency of bedload transport was examined in the lainbach river bavaria using magnetically tagged particles during the study 18 small to moderate events and one major event occurred about 1 per cent of the flow period exceeded the entrainment threshold and at least once every year about 50 per cent of the tagged particles were mobile themajor event which occurred during the study period resulted in the deposition of a thick layer of sediment in parts of the channel and passive burial of most of the recovered particles the step pool pattern which characterized the study site prior to the large event was obliterated however the channel recovered quickly and has returned to a new step pool pattern the event changed the boundary conditions by increasing the availability of loose sediment and creating higher river bed slopes in reaches between breached check dams as a result movement of individual particles measured for events of both the same magnitude and duration occurring before and after the large event yielded different values for events which occurred after the large event the range and the mean distance of movement were about ten times higher

1923 gleno dam break case study and numerical modeling on the morning of december 1 1923 the gleno dam located in the central italian alps suddenly collapsed a few days after the first complete reservoir filling nearly 4 5 1 0 6 m 3 of water was released the consequent inundation caused significant destruction along the downstream valley and a death toll of at least 356 lives this failure is the only historical case of dam break caused by structural deficiencies that has occurred in italy as a result it has deeply influenced the evolution of italian regulations regarding dam design and hydraulic risk evaluation however in spite of its relevance this event has never been characterized from a hydraulic standpoint this paper reports the main information obtained from the analysis of a vast amount of historical documents regarding the gleno dam break to set up a case study useful for validating dam break models in mountain settings moreover it presents the main results of one dimensional 1d modeling of the dam break wave propagation accomplished with a first order finite volume numerical scheme recently proposed in the literature for field applications the overall effectiveness and reliability of the model are evaluated for this case characterized by very irregular topography finally the practical relevance of several choices that the numerical reconstruction of this kind of event demands is tested doi 10 1061 asce hy 1943 7900 0000327 2011 american society of civil engineers ce database subject headings dam failures shallow water numerical models hydraulic models case studies italy author keywords dam failure 1d dam break modeling shallow water finite volume numerical model hydraulic hazard case study

soft sediment deformation structures interpreted as seismites in middle late pleistocene aeolian deposits apulian foreland southern italy abstract soft sediment deformation structures in middle late pleistocene deposits of torre san gennaro brindisi southern italy have been analysed from a morphologic point of view the deformational structures are represented by deformed cross bedding and large injection structures they are restricted to aeolian sediments and the mechanism of deformation is related to liquefaction and or fluidization processes the liquefaction and or fluidization processes have been interpreted as seismic induced after consideration of all other possible trigger agents the discussion about the possible source areas of the palaeoseismic event was carried out through the analysis both of the general magnitude distance relations and the main structural features of the study zone in conclusion we consider the key criteria for trigger mechanism interpretation of soft sediment deformation structures in aeolian deposits and the actual feasibility of using aeolian sediments for the palaeoseismic studies

stochastic model for the long term transport of stored sediment in a river channel we develop a stochastic model for the transport of stored sediment down a river channel the model is based on probabilities of transition of particles among four different sediment storage reservoirs called active often mobilized semiactive inactive and stable hardly ever mobilized the probabilities are derived from computed sediment residence times two aspects of sediment storage are investigated flushing times of sediment out of a storage reservoir and changes in the quantity of sediment stored in different reservoirs due to seasonal sediment transport into and out of a reach we apply the model to redwood creek a gravel bed river in northern california although the redwood creek data set is incomplete the application serves as an example of the sorts of analyses that can be done with the method the application also provides insights into the sediment storage process sediment flushing times are highly dependent on the degree of interaction of the stable reservoir with the more mobile sediment reservoirs the most infrequent and highest intensity storm events which mobilize the stable reservoir are responsible for the long term shifts in sediment storage turnover times of channel sediment in all but the stable reservoir are on the order of 750 years suggesting this is all the time needed for thorough interchange between these sediment compartments and cycling of most sediment particles from the initial reservoir to the ocean finally the markov model has adequately characterized sediment storage changes in redwood creek for 1947 1982 especially for the active reservoir the model replicates field observation of the passage of a slug of sediment through the active reservoir of the middle reach of redwood creek in the 18 years following a major storm in 1964 that introduced large quantities of landslide debris to the channel

2004 indian ocean tsunami flow velocity measurements from survivor videos 1 the tsunami of 26th december 2004 severely affected banda aceh along the north tip of sumatra indonesia at a distance of 250 km from the epicenter of the magnitude 9 0 earthquake this tsunami flow velocity analysis focused on two survivor videos recorded within banda aceh more than 3 km from the open ocean the exact locations of the tsunami eyewitness video recordings were revisited by the survey team between february 22 and 25 2005 to record camera calibration ground control points the motion of the camera during the recordings was determined the individual video images were rectified with a direct linear transformation dlt assuming a planar water surface at the level finally a cross correlation based particle image velocimetry piv analysis was applied to the rectified video images to determine instantaneous tsunami flow velocity fields the measured tsunami flow velocities were within the range of 2 to 5 m s

surface based fractional transport rates mobilization thresholds and partial transport of a sand gravel sediment twenty eight coupled observations of flow transport and bed surface grain size distribution were made in a laboratory flume using a wide range of flows and a sediment with a very poorly sorted bimodal grain size distribution these observations permit the transport rates of individual size fractions to be scaled by the proportion of each size immediately available for transport on the bed surface the key to our observations is the use of a sediment in which each size fraction has been painted a different color which permits reliable repeatable and nondestructive measurement of the bed surface grain size distribution from photographs of the bed surface at a given flow the fractional transport rates may be divided into two parts a finer grained portion within which fractional transport rates are a function only of their proportion on the bed surface and total transport rate and a coarser grained portion for which fractional transport rates also depend on the proportion of individual grains within a fraction that remain essentially immobile throughout the experimental run we define the latter condition as one of partial transport and observe that the grain size separating partial and fully mobilized transport consistently increases with flow strength complete mobilization of a size fraction occurs at roughly twice the shear stress necessary for incipient motion of that fraction zones of partial and full mobility are quite distinct when fractional transport rates are scaled by the bed surface grain size distribution although a region of partial transport is evident when these data and other experimental and field observations are scaled by the bulk grain size distribution of the sediment bed critical shear stresses for the incipient motion of individual fractions in our experimental sediment vary over an order of magnitude a result strongly in contrast to many earlier observations but consistent with our observations of incipient motion in sediments with bimodal grain size distributions

maximum impact force of woody debris on floodplain structures we collided woody debris i e logs with structures using flume and test basin laboratory facilities to investigate the maximum impact force that floodplain structures are exposed to from floating woody debris the tests also investigated the influence of collision geometry determined by the debris orientation on impact on the maximum impact forces we reviewed the three approaches that represent the existing guidance for estimating maximum impact forces each approach estimates the maximum impact force based on the debris velocity and mass we show that all the existing approaches can be derived from a single degree of freedom model of the collision and can be considered to be equivalent the laboratory data show that the maximum impact force was associated with a log striking a rigid structure with its end oblique and eccentric collisions reduced the maximum impact load in a predictable and consistent manner the approach we refer to as contact stiffness a linear one degree of freedom model with no damping was able to reproduce the laboratory results over the entire range of data with an effective contact stiffness of 2 4 mn m

soft sediment deformation structures in nw germany caused by late pleistocene seismicity new data on seismically triggered soft sediment deformation structures in pleniglacial to late glacial alluvial fan and aeolian sand sheet deposits of the upper senne area link this soft sediment deformation directly to earthquakes generated along the osning thrust which is one of the major fault systems in central europe soft sediment deformation structures include a complex fault and fold pattern clastic dikes sand volcanoes sills irregular intrusive sedimentary bodies flame structures and ball and pillow structures the style of soft sediment deformation will be discussed with respect to brittle failure liquefaction and fluidization processes and was controlled by 1 the magnitude of the earthquake and 2 the permeability tensile strength and flexural resistance of the alluvial and aeolian sediments it is the first time in northern germany that fluidization and liquefaction features can be directly related to a fault the occurrence of seismicity in the late pleistocene and in the seventeenth century indicates ongoing crustal movements along the osning thrust and sheds new light on the seismic activity of northern germany the late pleistocene earthquake probably occurred between 15 9 1 6 and 13 1 1 5 ka the association of soft sediment deformation structures implies that it had a magnitude of at least 5 5

estimates of large magnitude late cambrian earthquakes from seismogenic soft sediment deformation structures central rocky mountains a variety of unusual early post depositional deformation structures exist in grainstone and flat pebble conglomerate beds of upper cambrian strata western colorado including slide scarps thrusted beds irregular blocks and internally deformed beds thrusted beds up to tens of centimetres thick record thrust movement of a part of a bed onto itself along a moderate to steeply inclined 15 to 40 ramp locally producing hanging wall lenses with fault bend geometries thrust plane orientations are widely distributed and in some cases nearly oppositely oriented in close proximity indicating that they did not form as failures acted upon by gravity forces irregular bedded to internally deformed blocks are isolated on generally flat upper bedding surfaces these features represent parts of beds that detached moved up onto and some distances across the laterally adjacent undisturbed bed surfaces deformation of thin intervals of mud on the ocean floor by moving blocks rules out the possibility of storm induced deformation because the mud was not eroded by high shear stresses that would accompany the extremely large forces required to produce and move the blocks finally internally deformed beds are characterized by large blocks fitted fabrics of highly irregular fragments and contorted lamination which represent heterogeneous deformation such as brecciation and liquefaction the deformation structures were produced by earthquakes linked to the reactivation of mesoproterozoic crustal scale shear zones in the central rockies during the late cambrian analysis of the deformation structures indicates very large body forces and calculated earthquake generated ground motion velocities of ca 1 6 m sec 1 these correspond to moment magnitudes of ca 7 0 or more and a mercalli intensity of x these are the only known magnitude estimates of phanerozoic other than quaternary large intensity earthquakes for the rocky mountain region and they are as large as or larger than previous estimates of proterozoic earthquakes along these major shear zones of the central rockies

stochastic theory of particle trajectories through alluvial valley floors abstract temporary storage of sediment within alluvial valley floors modulates the long term transport of sediment through landscapes the fate of weathering minerals or sediment bound constituents in fluvial environments depends on the relative time scales of constituent degradation and particle residence time within valleys particles follow a set of trajectories through valley floors some particles pass directly through the channel reaching the basin outlet rapidly after being introduced to the fluvial system others remain for long periods in deposits such as flood plains traditional sediment routing theory based on the principle of sediment mass conservation along reaches of channel does not account for exchanges of sediment with temporary sediment storage reservoirs outside the channel such as flood plains deltas and alluvial fans this article formalizes a theory that incorporates the role of such exchanges in the migration of sediment through river systems by computing the probabilistic s

soft sediment deformation structures in late albian to cenomanian deposits sao luis basin northern brazil evidence for palaeoseismicity soft sediment deformation structures from the alc ntara formation late albian to cenomanian sao luis basin northern brazil consist of 1 contorted structures which include convolute folds ball and pillow structures concave up paths with consolidation lamination recumbently folded cross stratification and irregular convolute stratification that grades into massive beds 2 intruded structures which include pillars dykes cusps and subsidence lobes and 3 brittle structures represented by fractures and faults displaying planes with a delicate ragged morphology and sharp peaks these structures result from a complex combination of processes mostly including reverse density gradients fluidization and liquefaction reverse density gradients promoted by differential liquefaction associated with different degrees of sediment compaction led to the genesis of convolute folds more intense deformation promoted the development of ball and pillow structures subsidence lobes and sand rolls which are attributed to denser and thus more compacted less liquefied portions that sank down into less dense more liquefied sediments irregular convolute stratification that grades into massive beds would have formed at periods of maximum deformation the subsidence of beds was accompanied by lateral current drag and fluid escape from water saturated sands in addition the fractures and faults record brittle deformation penecontemporaneous with sediment deposition all these mechanisms were triggered by a seismic agent as suggested by a combination of criteria including 1 the position of the study area at the edge of a major strike slip fault zone that was reactivated several times from the albian to the holocene 2 a relative increase in the degree of deformation in sites located closer to the fault zone 3 continuity of the deformed beds over large distances several kilometres 4 restriction of soft sediment deformation structures to single stratigraphic intervals bounded by entirely undeformed strata 5 recurrence through time and 6 similarities to many other earthquake induced deformational structures

how quiet was the epeiric sea when the middle cambrian zhangxia formation was deposited in sw beijing china abstract the middle cambrian zhangxia formation 65 km southwest of beijing city was deposited in an epeiric sea that extended over almost the entire north china palaeo plate including korea the depositional conditions under which the limestones were deposited are commonly considered to have been quiet although oolites indicating current and wave activity occur fairly frequently the presence of a large 6 m lens of breccia embedded in oolite raises the question however how quiet the depositional conditions actually were the lens is composed of a limestone breccia which occurs only rarely in the zhangxia formation but that is common in the late cambrian chaomidian formation it appears that the large lens was deposited as an entity this does not fit the commonly presumed quiet depositional conditions of its host rock therefore it may be concluded that the lens was put in place by a special event this event is interpreted to have been a form of mass movement more particularly sliding of a consolidated but not yet completely lithified breccia mass only once such a feature has been described before from an epeiric sea remarkably enough from the chaomidian formation at a distance of several hundreds of kilometres from the present study site although this feature thus seems to be extremely rare it is important as it indicates instable conditions such instable conditions in epeiric seas have not commonly been recognized thus far which implies that our idea of the conditions in this environment need to be re considered

explicit treatment of inheritance in dating depositional surfaces using in situ 10be and 26al we describe a new strategy for dating depositional landscape surfaces using in situ produced cosmogenic radionuclides crns that removes the complication of nuclide inheritance by clasts prior to depositon two amalgamated samples each consisting of 30 clasts one from the surface and one from a fixed depth in the subsurface constrain this crn inheritance and date the surface the inheritance may be used to estimate minimum exhumation rates and maximum transport times within the geomorphic system we test the technique using sup 10 be and sup 26 al to date the third fr3 of five terraces along the fremont river utah and the third wr3 of 15 along the wind river wyoming whereas effective ages based solely upon the surface samples yield 118 138 ka fr3 and 93 ka wr3 the subsurface samples reveal that inheritance accounts for 22 wr3 to 43 fr3 of the total crn concentration taking this into account yeilds terrace ages of nearly 61 81 ka for fr3 and nearly 67 76 ka for wr3 we explore the dependence of age estimates on the accumulation history of the terrace silt caps 22 refs 3 figs 1 tab

the use of passive integrated transponder pit tags to trace cobble transport in a mixed sand and gravel beach on the high energy oregon coast usa abstract cobble transport is investigated on a mixed sand and gravel beach on the high energy oregon coast using radio frequency identification technology rfid to detect passive integrated transponder pit tags inserted in the gravels pit tags are glass encapsulated transponders that are activated when an antenna passes near them with each tag characterized by its own unique identification number the tags are sealed within the cobbles minimizing any effect on the hydrodynamic character of the particles the tags draw power from the antenna itself and have a potential lifespan of up to 50 years pit tags are simple to use and inexpensive permitting the release and tracking of large numbers of gravel particles as a result pit tags have tremendous potential for examining the complexities of particle movement and the parameters that control their distribution on the beach our experiments have been conducted at cape lookout state park on the northern oregon coast on a composite beach where a seasonally variable sand beach fronts a mixed sand and gravel beach with the latter impacted by waves only during the winter when the sand beach is cut back a total of 400 cobble tracers have been released at five different locations subsequent monitoring of the gravel tracers revealed that they can be detected up to 1 m below the surface of the beach using a 1 0 m diameter antenna and up to 0 5 m below the surface using a smaller 0 3 m diameter antenna while their positions were determined using a trimble 5700 5800 rtk dgps survey system gravel tracer recovery rates were found to vary significantly between the different release points from as high as 90 recovery after 8 months to a low of 18 after 17 months the lowest recovery rates are thought to be due to the extent of aggradation of the sandy beach during the summer partially covering the gravel berm and burying the tracer particles to depths where they could not be detected by the antennas used with our rfid system relocation of the gravel tracers has revealed a predominant northward migration of the cobbles and locally demonstrate a strong cross shore transport both upslope and downslope movements initial attempts to examine the relationship between the transport distances and particle sizes and shapes have thus far revealed that the larger gravels are tending to outrun the smaller particles this is despite the fact that both small and large particles were found to be capable of being transported both short and long distances in contrast our results revealed no relationships between particle shape and distance moved in time it is expected that the pit tag tracers may begin to yield more definitive patterns of sorting the results did highlight that the gravel movement occurs predominantly near the sand gravel beach junction on the profiles a region dominated by a higher incidence of wave breaking and strong swash activity finally our analyses revealed the potential for using pit tags to provide field assessments of the abrasion rates of gravel particles having already found measurable degrees of weight loss to abrasion in our experiments

sediment mobility in a forced riffle pool forced riffle pools occur in gravel bed rivers where a large nonalluvial element leads to local scour and deposition to manage rivers where this type of morphology is found and to specify restoration measures that mimic this process more field data on sediment mobility in forced riffle pools is needed the objectives of this study are to describe the spatial variability of sediment mobility and deposition in a developing forced riffle pool and to use high resolution flow velocity measurements to explain the observed dynamics the field site is a forced riffle pool in moras creek a 6 m wide gravel bed stream with a 1 2 bed slope in quebec canada topography and the movement of sediment particles equipped with passive integrated transponder pit tags are surveyed through a series of competent floods bed shear stress is estimated from near bed measurements of time averaged velocity and turbulent kinetic energy the sediment transport regime of the creek is characterized by partial mobility exponential distributions of path lengths and a negative relation between particle size and path length full mobility occurs in the center of the pool and over the exit slope where flow is accelerated from the constriction of flow during two events above the bankfull discharge partial mobility occurs during the same events over the entrance slope to the pool lateral gradients of deposition and mobility suggest that the majority of sediment in motion is routed over the side bar at the entrance to the pool high levels of turbulence intensity that occur as a result of flow deceleration may explain the removal of finer sediments from the head of the pool

variation in the reference shields stress for bed load transport in gravel bed streams and rivers 1 the present study examines variations in the reference shear stress for bed load transport r using coupled measurements of flow and bed load transport in 45 gravel bed streams and rivers the study streams encompass a wide range in bank full discharge 1 2600 m3 s average channel gradient 0 0003 0 05 and median surface grain size 0 027 0 21 m a bed load transport relation was formed for each site by plotting individual values of the dimensionless transport rate w versus the reach average dimensionless shear stress the reference dimensionless shear stress r was then estimated by selecting the value of corresponding to a reference transport rate of w 0 002 the results indicate that the discharge corresponding to r averages 67 of the bank full discharge with the variation independent of reach scale morphologic and sediment properties however values of r increase systematically with average channel gradient ranging from 0 025 0 035 at sites with slopes of 0 001 0 006 to values greater than 0 10 at sites with slopes greater than 0 02 a corresponding relation for the bank full dimensionless shear stress bf formulated with data from 159 sites in north america and england mirrors the relation between r and channel gradient suggesting that the bank full channel geometry of gravel and cobble bedded streams is adjusted to a relatively constant excess shear stress bf r across a wide range of slopes

measuring gravel transport and dispersion in a mountain river using passive radio tracers random walk models of fluvial sediment transport recognize that grains move intermittently with short duration steps separated by rests that are comparatively long these models are built upon the probability distributions of the step length and the resting time motivated by these models tracer experiments have attempted to measure directly the steps and rests of sediment grains in natural streams this paper describes results from a large tracer experiment designed to test stochastic transport models we used passive integrated transponder pit tags to label 893 coarse gravel clasts and placed them in halfmoon creek a small alpine stream near leadville colorado usa the pit tags allow us to locate and identify tracers without picking them up or digging them out of the streambed they also enable us to find a very high percentage of our rocks 98 after three years and 96 after the fourth year we use the annual tracer displacement to test two stochastic transport models the einstein hubbell sayre ehs model and the yang sayre gamma exponential model gem we find that the gem is a better fit to the observations particularly for slower moving tracers and suggest that the strength of the gem is that the gamma distribution of step lengths approximates a compound poisson distribution published in 2012 this article is a us government work and is in the public domain in the usa

pseudoconglomerate and a re examination of some paleoenvironmental controversies pseudoconglomerate an unusual fragmental rock that contains pebblelike clasts is described from the barberton greenstone belt south africa it occurs in concordant and discordant bodies that are closely associated with silicification carbonation and in situ brecciation and veining pseudoconglomerate is interpreted as a product of submarine exhalative activity in a hemipelagic environment it is thought to develop in subsurface breccia bodies that form by hydraulic disaggregation of the host rock breccia clasts are jostled during continued fluid flow and become rounded as the result of attrition between adjacent fragments the previous interpretation of this rock as a normal marine sediment at barberton and possibly in other archean and paleozoic sequences may have resulted in paleoenvironmental misinterpretation

tracer pebble movement along a concave river profile virtual velocity in relation to grain size and shear stress over 1400 tracer pebbles 16 256 mm in diameter were tracked for 2 years in six reaches of allt dubhaig scotland a small gravel bed river along which shear stress and bed surface grain size decrease toward a local base level pebble movement was size selective both within and between reaches within reaches the decrease in mean travel distance with increasing grain size is strongest in the coarse tail of the size distribution particle shape has a minor secondary effect a nondimensional grain velocity averaged over the duration of competent flow is used to compare different size classes and reaches over 90 of its variance is explained by relative grain size and reach shields stress the pattern of size selectivity is consistent with single event tracer results elsewhere bedload trap data from our distal reach and the concept of partial mobility it provides a mechanism for strong downstream fining by selective transport and deposition along rivers in which stress declines toward base level the nondimensional prediction equation for grain velocity may be of use in other rivers but requires testing

substantial contribution to sea level rise during the last interglacial from the greenland ice sheet during the last interglacial period the eemian global sea level was at least three metres and probably more than five metres higher than at present1 2 complete melting of either the west antarctic ice sheet or the greenland ice sheet would today raise sea levels by 6 7 metres but the high sea levels during the last interglacial period have been proposed to result mainly from disintegration of the west antarctic ice sheet3 with model studies attributing only 1 2 m of sea level rise to meltwater from greenland4 5 this result was considered consistent with ice core evidence4 although earlier work had suggested a much reduced greenland ice sheet during the last interglacial period6 here we reconsider the eemian evolution of the greenland ice sheet by combining numerical modelling with insights obtained from recent central greenland ice core analyses our results suggest that the greenland ice sheet was considerably smaller and steeper during the eemian and plausibly contributed 4 5 5 m to the sea level highstand during that period we conclude that the high sea level during the last interglacial period most probably included a large contribution from greenland meltwater and therefore should not be interpreted as evidence for a significant reduction of the west antarctic ice sheet

bedload a granular phenomenon bedload the transport of sediment remaining in contact with the stream bed has mainly been studied from the perspective of the correlation between fluid driving forces and the responding sediment flux yet grain grain interactions are important and bedload should also be considered as a granular phenomenon we review progress made recently in the study of granular flows especially on segregation and rheology that better illuminates the nature of bedload granular flows may exhibit gas like or fluid like flow or quasi solid deformation all three conditions might be duplicated in bedload understanding of intense bedload transport occurring continuously in a layer several grains deep typical of sand beds might greatly benefit from results in granular physics as illustrated by grain inspired bedload results however processes restricted to the surface of the bed when particles move intermittently and the bed becomes structured while characteristic in gravel bed channels are not well addressed in granular physics mutual study of these phenomena may benefit both physics and fluvial geomorphology we intend therefore to contribute to an enhanced dialogue between granular physics and bedload science communities copyright 2010 john wiley sons ltd