the obliquity controlled early pleistocene terrace sequence of the gediz river western turkey a revised correlation and chronology the buried early pleistocene river terrace record of the gediz river around kula western turkey has previously been considered to span the time interval equivalent to marine isotope stages mis 58 37 c 1 6 1 2 ma with the frequency of terrace formation mirroring obliquity driven climate change whereas progressive pleistocene incision of the gediz river is seen as a response to regional uplift the timing of fluvial incision leading to terrace formation and subsequent new floodplain development is believed to be climate controlled with incision deposition cycles resulting from varying sediment discharge conditions a direct consequence of changing climate and related vegetation change new outcrop observations downstream of the original field area alongside recently published geochronological data and improved understanding of the volcanic sequence all now suggest that the previously published interpretation is incorrect here we present a revised stratigraphy based upon terrace gradients of c 0 004 0 005 previously 0 001 in which 11 terraces are identified but only terraces gt11 the oldest to gt6 pre lava incursion predate volcanism the available geochronology suggests that terraces gt6 post first lava incursion to gt1 relate to the time interval mis38 28 c 1 26 1 ma however despite penecontemporaneous volcanism terrace formation continues to reflect sediment discharge changes predominantly controlled by regional climate change

large scale erosion rates from in situ produced cosmogenic nuclides in european river sediments abstract we have calculated long term erosion rates of 20 100 mm kyr from quartz contained 10be in the bedload of middle european rivers for catchments ranging from 102 to 105 km2 these rates average over 10 40 kyr and agree broadly with rock uplift incision and exhumation rates historic soil erosion rates and erosion rates calculated from the measured sediment loads of the same rivers moreover our new erosion rate estimates correlate well with lithology and relief however in the regen neckar loire and meuse catchments cosmogenic nuclide derived erosion rates are consistently 1 5 4 times greater than the equivalent rates derived from measured river loads this may be due to the systematic under representation of high magnitude low frequency transport events in the gauging records which cover less than a century alternatively the discrepancy may derive from spatially non uniform erosion and preferential tapping of deeper sections of the irradiation profile a third explanation relates the high cosmogenic nuclide derived erosion rates to inheritance of an elevated pleistocene erosion signal uncertainties associated with the cosmogenic nuclide derived erosion rate estimates are not greater than the potential errors in conventional estimates therefore the cosmogenic nuclide approach is an effective tool for rapid catchment wide assessment of time integrated rates of bedrock weathering and erosion and we anticipate its fruitful application to the quaternary sedimentary record

modelled atmospheric temperatures and global sea levels over the past million years the climate has passed through a series of glacials and interglacials over the past million years but the nature of this cyclicity in terms of temperature ice volume and sea level and the underlying causes are not well known bintanja et al use a new method to deduce a one million year time series of these variables the reconstructed records are much longer than other methods have provided for any of these variables individually the most intense glacial stages were 17 c colder than today and most of the continental ice was present in north america strong cooling in the beginning of glacials was found to precede ice sheet build up these findings may shed light on the causes of ice age cycles marine records of sediment oxygen isotope compositions show that the earth s climate has gone through a succession of glacial and interglacial periods during the past million years but the interpretation of the oxygen isotope records is complicated because both isotope storage in ice sheets and deep water temperature affect the recorded isotopic composition1 2 3 4 5 separating these two effects would require long records of either sea level or deep ocean temperature which are currently not available here we use a coupled model of the northern hemisphere ice sheets6 and ocean temperatures forced to match an oxygen isotope record for the past million years compiled from 57 globally distributed sediment cores to quantify both contributions simultaneously we find that the ice sheet contribution to the variability in oxygen isotope composition varied from ten per cent in the beginning of glacial periods to sixty per cent at glacial maxima suggesting that strong ocean cooling preceded slow ice sheet build up the model yields mutually consistent time series of continental mean surface temperatures between 40 and 80 n ice volume and global sea level we find that during extreme glacial stages air temperatures were 17 1 8 c lower than present with a 120 10 m sea level equivalent of continental ice present

a 3 d model of quaternary terrace development simulations of terrace stratigraphy and valley asymmetry a case study for the allier terraces limagne france the combined effects of climate and tectonism on general terrace stratigraphy and valley asymmetry during the last half million years in the allier system france are simulated by a 3 d conceptual model limter this model allows the formulation and evaluation of long term terrace formation scenarios for the allier system simulation results suggest that terrace stratigraphy in the study area is mainly the result of internal dynamics and climatic change local tectonism contributed to the development of unpaired terraces while the general regional uplift played a dominant role in determining terrace formation and preservation in general

predicting reach specific properties of fluvial terraces to guide future fieldwork a case study for the late quaternary river allier france with the fluver2 model numerical models have not yet systematically been used to predict properties of fluvial terrace records in order to guide fieldwork and sampling this paper explores the potential of the longitudinal profile model fluver2 to predict testable field properties of the relatively well studied late quaternary allier system in france for the allier terraces an overlapping 14c and u series chronology as well as a record of 10be erosion rates exist the fluver2 modelling exercise is focused on the last 50 ka of the upper allier reach because for this location and period the constraints of the available dating techniques are tightest a systematic calibration based on terrace occurrence and thicknesses was done using three internal parameters related to 1 the sediment erodibility 2 the sediment transport distance and 3 the sediment supply derived from the surrounding landscape as external model inputs the best available reconstructed tectonic climatic and base level data were used calibrated model outputs demonstrate a plausible match with the existing fluvial record validation of model output was done by comparing the modelled and measured timing of aggradation and incision phases for the three locations the modelled range of landscape erosion rates showed a reasonably good match with existing erosion rate estimates derived from 10be measurements of fluvial sands the quasi validated model simulation was subsequently used to make new testable predictions about the timing and location of aggradation and erosion phases for three locations along the allier river the validated simulations predict that along the allier reach specific dynamics of incision and aggradation related to the variations in sediment supply by major tributaries cause relevant differences in the local fluvial terrace stratigraphy numerical models have not yet systematically been used to predict properties of fluvial terrace records in order to guide fieldwork and sampling this paper explores the potential of the longitudinal profile model fluver2 to predict testable field properties of the relatively well studied late quaternary allier system in france for the allier terraces an overlapping 14 c and u series chronology as well as a record of 10 be erosion rates exist the fluver2 modelling exercise is focused on the last 50 ka of the upper allier reach because for this location and period the constraints of the available dating techniques are tightest a systematic calibration based on terrace occurrence and thicknesses was done using three internal parameters related to 1 the sediment erodibility 2 the sediment transport distance and 3 the sediment supply derived from the surrounding landscape as external model inputs the best available reconstructed tectonic climatic and base level data were used calibrated model outputs demonstrate a plausible match with the existing fluvial record validation of model output was done by comparing the modelled and measured timing of aggradation and incision phases for the three locations the modelled range of landscape erosion rates showed a reasonably good match with existing erosion rate estimates derived from 10 be measurements of fluvial sands the quasi validated model simulation was subsequently used to make new testable predictions about the timing and location of aggradation and erosion phases for three locations along the allier river the validated simulations predict that along the allier reach specific dynamics of incision and aggradation related to the variations in sediment supply by major tributaries cause relevant differences in the local fluvial terrace stratigraphy copyright 2016 john wiley sons ltd

evaluating choices in multi process landscape evolution models the interest in landscape evolution models lems that simulate multiple landscape processes is growing however modelling multiple processes constitutes a new starting point for which some aspects of the set up of lems must be re evaluated the objective of this paper is to demonstrate the practical significance of and possibilities for such re evaluation we first discuss which simplifications must be made to set up lems then simplifications of particular interest to the modelling of multiple processes are identified finally case studies from new zealand belgium and croatia explore the performance of different model versions under several common choices for model and data simplifications in these case studies we illustrate methods to make the choices typically by i comparing the results of different model versions ii assessing model validity or iii indicating the sensitivity of models for different simplifications the results indicate that lem performance is strongly dependent on multi process related choices and that performance indicators can be used for ex post testing of the influence of these choices in particular we demonstrate the significance of simplifications regarding the number of processes presence of sinks and temporal resolution

modelling landscape evolution geomorphology is currently in a period of resurgence as we seek to explain the diversity origins and dynamics of terrain on the earth and other planets in an era of increased environmental awareness yet there is a great deal we still do not know about the physics and chemistry of the processes that weaken rock and transport mass across a planet s surface discovering and refining the relevant geomorphic transport functions requires a combination of careful field measurements lab experiments and use of longer term natural experiments to test current theory and develop new understandings landscape evolution models have an important role to play in sharpening our thinking guiding us toward the right observables and mapping out the logical consequences of transport laws both alone and in combination with other salient processes improved quantitative characterization of terrain and process and an ever improving theory that describes the continual modification of topography by the many and varied processes that shape it together with improved observation and qualitative and quantitative modelling of geology vegetation and erosion processes will provide insights into the mechanisms that control catchment form and function this paper reviews landscape theory in the form of numerical models of drainage basin evolution and the current knowledge gaps and future computing challenges that exist copyright 2010 john wiley sons ltd

long term behaviour of continental hydrothermal systems u series study of hydrothermal carbonates from the french massif central allier valley abstract u series dating of hydrothermal carbonates deposited by co2 rich thermo mineral waters of the french massif central provides new insights on the long term behaviour of a continental hydrothermal system dating of aragonite veins and travertines impregnating old terrace levels of the allier river allowed identification of the main episodes of surface deposition and thus factors likely to influence these circulations fifteen layers from three veins and four travertines from two separate areas were analysed sr isotope compositions were also measured on vein samples the results show that this region was subjected to at least 3 main episodes of surface or near surface hydrothermal deposition 253 to 208 ky 135 to 100 ky and less than 8 ky comparison of these ages with a global climatic curve indicates that preferential deposition of carbonates occurs during warm periods suggesting a strong influence of climatic conditions on the hydrothermal system it is suggested that this climatic influence does not necessarily imply the absence of carbonate deposition during cold and dry periods but rather that carbonate precipitation might occur at depth before the geothermal fluids reach the surface in addition the isotope compositions of fluids recorded by the 87sr 86sr and 234u 238u initial ratios in the aragonite veins from coudes remained remarkably constant over 250 ky ranging from 0 71360 to 0 71371 and from 3 10 to 3 39 respectively the two samples coming from saladis show a slightly higher 234u 238u initial ratio around 3 95 the constancy of these ratios over such a long period suggests a hydrothermal system in a near steady state with respect to water rock interaction we thus propose a possible model allowing a conservative steady state despite variations in the water recharge rates in response to the climatic variations the difference between 234u 238u initial ratios measured in the coudes and saladis systems suggests the existence of two separate reservoirs and constrains their lateral extension to a few km at most

reconstructing the interacting effects of base level climate and tectonic uplift in the lower mino river terrace record a gradient modelling evaluation the origin of the lower mino river terraces in the nw iberian peninsula has been a topic of debate since the 1940s various hypotheses about their main controlling factors have been put forward but general consensus is still lacking field studies of terrace distribution and the weathering of quartzite pebbles in the terrace deposits demonstrated that terrace longitudinal correlation is not parallel to the current river bed in addition the longitudinal profile model fluver2 was used to simulate the profile evolution of the mino river over the past 450 ka a reconstructed longitudinal profile and an offshore climate record were used as inputs several scenarios with variable uplift rates were investigated and evaluated against properties of four selected reaches along the river for a match with the number of terraces their relative altitude timing and sediment thickness an uplift scenario with a net constant vertical uplift rate of 0 08 m ka 1 yielded the best results the best fit scenarios indicate that base level changes from glacioeustatic changes in combination with tectonic uplift are the main driving forces of the observed terrace formation and valley incision contrary to most nw european fluvial systems the timing of upstream controlled sediment supply has a less dominant effect on terrace formation this can be explained by the close proximity to the narrow passive atlantic margin

modelling the long term fluvial erosion of the river somme during the last million years a process based model that simulates fluvial erosion in the river somme valley over the last million years is presented here the model takes into account lithology and climatic influences and allows the simulating of undercapacity and overcapacity sediment transport behaviour the model has been calibrated to a family of terraces within the river somme valley when matched to this field data simulation trials suggest that bedrock incision occurred principally from 120 to 60 40 kyr during the last climatic cycle and before the last glaciation the impact of a progressive tectonic uplift c 60 m over c 1 million years on the river somme has also been studied here extended over a longer period of time the simulations suggest that 1 million years ago the profile of the river somme had a lower slope gradient than today with little relief throughout the paris basin

evidence from the florida straits for younger dryas ocean circulation changes 1 the waters passing through the florida straits today reflect both the western portion of the wind driven subtropical gyre and the northward flow of the upper waters which cross the equator compensating north atlantic deep water export as part of the large scale atlantic meridional overturning circulation it has been postulated from various lines of evidence that the overturning circulation was weaker during the younger dryas cold event of the last deglaciation we show here that the contrast in the oxygen isotopic composition of benthic foraminiferal tests across the florida current is reduced during the younger dryas this most likely reflects a decrease in the density gradient across the channel and a decrease in the vertical shear of the florida current this reduced shear is consistent with the postulated reduction in the atlantic meridional overturning circulation we find that the onset of this change in density structure and flow at the start of the younger dryas is very abrupt occurring in less than 70 years

modelling long term 300 ka upland catchment response to multiple lava damming events landscapes respond in complex ways to external drivers such as base level change due to damming events in this study landscape evolution modelling was used to understand and analyse long term catchment response to lava damming events palaeodem reconstruction of a small turkish catchment 45km 2 that endured multiple lava damming events in the past 300ka was used to derive long term net erosion rates these erosion rates were used for parameter calibration and led to a best fit parameter set this optimal parameter set was used to compare net erosion landscape time series of four scenarios i no uplift and no damming events ii no uplift and three damming events iii uplift and no damming events and iv uplift and three damming events spatial evolution of net erosion and sediment storage of scenario iii and iv were compared simulation results demonstrate net erosion differences after 250 000years between scenarios with and without dams initially trunk gullies show less net erosion in the scenario with damming events compared with the scenario without damming events this effect of dampened erosion migrates upstream to smaller gullies and local slopes finally an intrinsic incision pulse in the dam scenario results in a higher net erosion of trunk gullies while decoupled local slopes are still responding to the pre incision landscape conditions sediment storage differences also occur on a 100ka scale these differences behaved in a complex manner owing to different timings of the migration of erosion and sediment waves along the gullies for each scenario although the specific spatial and temporal sequence of erosion and deposition events is sensitive to local parameters this model study shows the manner in which past short lived events like lava dams have long lasting effects on catchment evolution copyright c 2014 john wiley sons ltd

a device for measuring gully headwall morphology this paper describes a low cost device for measuring the three dimensional morphology of a gully headwall the device was designed to operate in a gully system with the following characteristics overhanging banks caused by a thick dense root mat retreat of the underlying unconsolidated sediments through small slab failures leading to a considerable variation in retreat rate at each point on the headwall and changes in the orientation of the headwall owing to changes in sediment properties and the topographical and hydrological controls of gully growth the device is used to measure a series of closely spaced vertical profiles of the headwall and the collected data are combined to draw a contour map showing the distance from the plane of the instrument to the headwall comparing maps for sequential times enables retreat rates for the diffferent proportions of the headwall to be quantified

simulating internal and external controls on fluvial terrace stratigraphy a qualitative comparison with the maas record palaeohydrological studies indicate that the use of sedimentary palaeoclimatic indicators in fluvial sediments still requires rigorous calibration of the climatic controls on the formation of those indicators an explorative attempt is made using a simulation experiment with the fluver2 model the simulation illustrates that climate control on the erosion sedimentation behaviour of a large fluvial system differs along the fluvial system while in the uplifting hinterland only glacial extremes are recorded as sediments with a relatively limited preservation chance as terraces due to the uplift the more downstream reach towards the hinge zone displays a sensitive fluvial record registering even stadial interstadial dynamics well preserved in an extensive glacial interglacial terrace staircase downstream in a subsiding basin the most complete sedimentary record is preserved which still contains temporal gaps of approximately 20 related to the spatial delay effects of the external control of climate and related base level change a systematic comparison of simulated climate changes and resulting fluvial dynamics illustrates that due to the internal control of fluvial systems a one to one correlation between recorded fluvial dynamics and climate change becomes less the further one moves downstream along the longitudinal profile a qualitative comparison of the simulation results with the maas record reveals an interesting match suggesting that the simulated system dynamics may well apply the maas system

an integrated field and numerical modelling study of controls on late quaternary fluvial landscape development tabernas southeast spain the variability of quaternary landforms preserved in the tabernas basin of southeast se spain raises numerous questions concerning the roles of external forcing mechanisms e g tectonics and or climate and internal landscape properties e g lithological controls in the evolution of the basin wide fluvial system over late quaternary timescales in this study we apply the fluver2 numerical model to investigate the significance of these landscape controls upon patterns of landscape evolution we highlight the complications of generating realistic input datasets for use in the modelling of long term landscape evolution e g discharge and runoff datasets model outputs are compared to extensive field mapping of fluvial terraces their sedimentary architecture and optically stimulated luminescence dating results of the terraces the results demonstrate the significance of non linear rates of flexural tectonic uplift towards the west of the tabernas basin which have controlled base levels throughout the quaternary and promoted the formation of a series of diverging fluvial terraces our numerical model results further highlight the importance of climate cycles upon river terrace formation basin wide aggradation events were modelled during the transition from marine isotope stage mis 6 to 5 and the last glacial maximum lgm as supported by field evidence this aggradational pattern supports the regional hypothesis of terrace formation during global glacial cycles and cold to warm stage transitions and supports the use of sea surface temperature climate proxy data in the modelling exercise the availability of sediments derived from the surrounding hillslopes and adjacent alluvial fans explains the generation of substantial terrace aggradations copyright 2015 john wiley sons ltd

the climate in western europe during the last glacial interglacial cycle derived from pollen and insect remains using the pollen sequence of la grande pile xx france we review problems with the application of transfer functions in paleoclimatic reconstructions one of them is to find modern analogues for the herbaceous vegetation of the cold periods we propose a method to distinguish between steppes and tundra vegetations for which the moderns are only partial analogues of the glacial periods another method to solve these problems is based on constraining by insect remains the two methods provide coherent reconstructions the results are also compared with other paleodata there is a good correlation with the six cold heinrich events between 70 and 15 ka b p a cooling event during the eemian period marked by high percentages of taxas at about 125 ka b p needs still to be correlated with high resolution ocean and ice cores

tectonic and climatic controls on knickpoint retreat rates and landscape response times 1 the rate at which transient knickpoints propagate through a landscape fundamentally controls the rate of geomorphic response to tectonic and climatic perturbation here we present knickpoint retreat rates upstream of active faults for 19 bedrock catchments in turkey and 11 bedrock catchments in italy where we have very good constraints on both the magnitude and timing of the tectonic perturbation and where climate histories are well documented we show that the knickpoints have average retreat rates of between 0 2 and 2 mm yr for catchments with drainage areas between 6 and 65 km2 and we test whether differences in rock mass strength and catchment size are sufficient to explain this range in retreat rates our analysis suggests that even accounting for these two variables knickpoint propagation velocities differ markedly and we show that channels crossing faults with higher throw rates have knickpoints that are retreating faster the dependence of knickpoint retreat velocity on throw rate is at least as important as catchment drainage area these results indicate counterintuitively that landscapes forced by large amplitude tectonic perturbations will have shorter response times than those perturbed by smaller amplitude changes the link between the knickpoint propagation velocity and throw rate is largely but not completely explained by channel narrowing in areas of high uplift rate channel steepening upstream of the active faults may explain all of the residual dependency of knickpoint retreat rate on fault throw rate but only if the slope exponent n in the standard stream power model is greater than 1 3 however we cannot rule out a role for sediment supply in driving enhanced knickpoint retreat rate in addition to the well documented channel narrowing effect finally we find that mean knickpoints retreat rates in turkey are only half of those in italy for catchments of equivalent size crossing faults with similar throw rates this difference in fluvial response time is accounted for by long term differences in the ratio of precipitation to infiltration in the two areas over the last 1 my

modelling centennial sediment waves in an eroding landscape catchment complexity sediment flux dynamics in fluvial systems have often been related to changes in external drivers of topography climate or land cover it is well known that these dynamics are non linear recently model simulations of fluvial activity and landscape evolution have suggested that self organization in landscapes can also cause internal complexity in the sedimentary record in this contribution one particular case of self organization is explored in the sabinal field study area spain where several dynamic zones of sedimentation and incision are observed along the current river bed whether these zones can be caused by internal complexity was tested with landscape evolution model lem lapsus landscape process modelling at multi dimensions and scales during various 500 year simulations zones of sedimentation appear to move upstream and downstream in eroding river channels waves these waves are visualized and characterized for a range of model settings under constant external forcing and the self organizing process behind their occurrence is analysed results indicate that this process is not necessarily related to simplifications in the model and is more generic than the process of bed armouring that has recently been recognized as a cause for complexity in lem simulations we conclude that autogenic sediment waves are the result of the spatial propagation in time of feedbacks in local transport limited deposition and detachment limited erosion conditions

a 30 000 yr record of erosion rates from cosmogenic 10be in middle european river terraces abstract cosmogenic 10 be in river borne quartz sand records a time integrated erosion rate representative of an entire drainage basin when sequestered in a terrace of known age paleo erosion rates may be recovered from the nuclide content of the terrace material paleo erosion rates between 30 and 80 mm kyr are determined from terrace sediments 200 to 30 000 yr in age of the allier and dore rivers france and the meuse maas river the netherlands erosion rates determined from cosmogenic nuclides on terraces from the allier river are consistent with rates derived from the sedimentary fill of a lake in the allier catchment a strong decrease in cosmogenic nuclide derived erosion rates from terraces of the meuse river with late pleistocene to holocene age is observed the paleo erosion signal from cosmogenic nuclides records projection of the elevated late pleistocene erosion rate into the time integrated rates derived from middle european rivers

numerical modeling of fluvial strath terrace formation in response to oscillating climate many river systems in western north america retain a fluvial strath terrace rec ord of discontinuous downcutting into bedrock through the quaternary their importance lies in their use to interpret climatic events in the headwaters and to determine long term incision rates terrace formation has been ascribed to changes in sediment supply and or water discharge produced by late quaternary climatic fluctuations we use a one dimensional channel evolution model to explore whether temporal variations in sediment and water discharge can generate terrace sequences the model includes sediment transport vertical bedrock erosion limited by alluvial cover and lateral valley wall erosion we set limits on our modeling by using data collected from the terraced wind river basin two types of experiments were performed constant period sinusoidal input histories and variable period inputs scaled by the marine 18 o rec ord our simulations indicate that strath terrace formation requires input variability that produces a changing ratio of vertical to lateral erosion rates straths are cut when the channel floor is protected from erosion by sediment and are abandoned and terraces formed when incision can resume following sediment cover thinning high sediment supply promotes wide valley floors that are abandoned as sediment supply decreases in contrast wide valleys are promoted by low effective water discharge and are abandoned as discharge increases widening of the valley floors that become terraces occurs over many thousands of years the transition from valley widening to downcutting and terrace creation occurs in response to subtle input changes affecting local divergence of sediment transport capacity formation of terraces lags by several thousand years the input changes that cause their formation our results suggest that use of terrace ages to set limits on the timing of a specific event must be done with the knowledge that the system can take thousands of years to respond to a perturbation the incision rate calculated in the field from the lowest terrace in these systems will likely be higher than the rate calculated by using older terraces because the most recent fluvial response in the field is commonly downcutting associated with declining sediment input since the last glacial maximum this apparent increase in incision rates is observed in many river systems and should not necessarily be interpreted as a response to an increase in rock uplift rate

delayed delivery from the sediment factory modeling the impact of catchment response time to tectonics on sediment flux and fluvio deltaic stratigraphy the sediment flux from a catchment is driven by tectonics and climate but is moderated by the geomorphic response of the landscape system to changes in these two boundary conditions consequently catchment response time and the non linear behavior of landscapes in response to boundary condition change control the downstream propagation of climatic or tectonic perturbations from catchments to neighboring basins in order to investigate the impact of catchment response time on sediment flux we integrated a spatially lumped numerical model pacmod with new routines simulating the evolution of landscape morphology and erosion rates under tectonic and climatic forcing we subsequently applied the model to reconstruct the sediment flux from a tectonically perturbed catchment in central italy finally we coupled our model to deltasim a process response model simulating fluvio deltaic stratigraphy and investigated the impact of catchment response time on stratigraphy using both synthetic scenarios and a real world system fucino basin central italy our results demonstrate that the differential response of geomorphic elements to tectonic and climatic changes induces a complex sediment flux signal and produces characteristic stratigraphic architectures and shoreline trajectories copyright 2014 john wiley sons ltd

a cellular model of holocene upland river basin and alluvial fan evolution coulthard t j macklin m g kirkby m j 2002 a cellular model of holocene upland river basin and alluvial fan evolution earth surface processes and landforms 27 3 269 288

the construction of a palaeodischarge time series for use in a study of fluvial system development of the middle to late pleistocene upper thames recently many studies have attempted to model fluvial system development over a variety of geographical and temporal scales it is generally recognised that one of the main problems especially in studies over longer timescales 100 ka is the reconstruction of a robust palaeodischarge time series over such extended timescales discharge can only be reconstructed using proxy data i e either field based sediment palaeodischarge estimates or transformation of reconstructed palaeoclimate data series e g ice core data with only the latter method allowing the reconstruction of a continuous time series in this study of the upper thames catchment uk we have developed a new palaeodischarge time series a sea surface temperature record odp 980 from the north atlantic off the west coast of ireland is used as a proxy for precipitation across the upper thames catchment a vegetation filter based on pollen data is then applied to this precipitation record in order to create a runoff model finally this runoff model is transformed to a discharge model via the use of a climate change function which attempts to reflect probable changes in the frequency and magnitude of discharge events using our new palaeodischarge model we present output from the fluver2 model of longitudinal profile development for the middle to late pleistocene upper thames valley this model simulates the possible timing and magnitude of sediment aggradation degradation events on the floodplain as well as the timing of floodplain abandonment due to tectonic uplift resulting in terrace formation copyright 2010 john wiley sons ltd

modeling the response of the rhine meuse fluvial system to late pleistocene climate change abstract we use a landscape evolution model to infer the effect of late pleistocene climate change on the incision aggradation behaviour of the rhine meuse fluvial system we model the routing of runoff and sediment in the catchment in order to predict grainsize trends and the incision and aggradation behaviour in the downstream reach where we compare it to the sequence of events and grainsize characteristics inferred from borehole corings this sequence starts with an important incision taking place around the mis 3 to mis 2 climatic transition during the coldest part of mis 2 a coarse grained sedimentary unit is deposited that shows an upward increase in the sand gravel ratio the model experiments do not predict an incision at the mis 3 to mis 2 transition therefore the incision should be attributed to other causes most likely effects of glacio isostatic uplift however a relative upward increase in sand content of the sediments is predicted by the model this increase is the result of the difference in transport rates between sand and gravel starting from a homogeneous pre existing mis 3 deposit the gravel content in the active layer increases because the sand is removed quickly and transported further downstream whereas the gravel travels slowly and piles up with gravel originating from immediately upstream resulting in a net accumulation at a later stage sand originating from much further upstream progrades fan like over the gravelly deposits according to the record during the early late glacial warming part of mis 2 bolling allerod interstadial neither incision nor aggradation has taken place this is in accordance with modelling results which show that despite the reduction of sediment input due to re vegetation of hillslopes sufficient sediment remains available for fluvial transport in the channel network itself it takes several thousands of years before effects of sediment depletion in the catchment are noted downstream that is why we argue that the inferred incision at the late late glacial the start of the younger dryas in our downstream study area might reflect depletion effects related to the preceding early late glacial conditions in general our modelling results show that terraces along one large fluvial system are diachronic features in particular terrace surfaces are older upstream compared to downstream in addition complex responses to climate change are likely to occur in a large fluvial system like the rhine meuse and correlation of morphological features in the fluvial record to specific short term palaeo climatic events for example dansgaard oeschger events could be risky without consideration of catchment size characteristics and associated response times

fluvial responses to climate and sea level change a review and look forward summary fluvial landforms and deposits provide one of the most readily studied quaternary continental records and alluvial strata represent an important component in most ancient continental interior and continental margin successions moreover studies of the long term dynamics of fluvial systems and their responses to external or allogenic controls can play important roles in research concerning both global change and sequence stratigraphy as well as in studies of the dynamic interactions between tectonic activity and surface processes these themes were energized in the final decades of the twentieth century and may become increasingly important in the first decades of this millennium this review paper provides a historical perspective on the development of ideas in the fields of geomorphology quaternary geology vs sedimentary geology and then summarizes key processes that operate to produce alluvial stratigraphic records over time scales of 103 106 years of particular interest are changes in discharge regimes sediment supply and sediment storage en route from source terrains to sedimentary basins as well as changes in sea level and the concept of accommodation late quaternary stratigraphic records from the loire france mississippi usa colorado texas usa and rhine meuse the netherlands rivers are used to illustrate the influences of climate change on continental interior rivers as well as the influence of interacting climate and sea level change on continental margin systems the paper concludes with a look forward to a bright future for studies of fluvial response to climate and sea level change at present empirical field based research on fluvial response to climate and sea level change lags behind a the global change community s understanding of the magnitude and frequency of climate and sea level change b the sequence stratigraphic community s desire to interpret climate and especially sea level change as forcing mechanisms and c the modelling community s ability to generate numerical and physical models of surface processes and their stratigraphic results a major challenge for the future is to catch up which will require the development of more detailed and sophisticated quaternary stratigraphic sedimentological and geochronological frameworks in a variety of continental interior and continental margin settings there is a particular need for studies that seek to document fluvial responses to allogenic forcing over both shorter 102 103 years and longer 104 106 years time scales than has commonly been the case to date as well as in larger river systems from source to sink studies of quaternary systems in depositional basin settings are especially critical because they can provide realistic analogues for interpretation of the pre quaternary rock record

modelling the impact of regional uplift and local tectonics on fluvial terrace preservation abstract a terrace formation model terrace combined with a longitudinal river profile model fluver was used to simulate fluvial terrace formation and preservation in the northwest iberian lower mino river basin under the influence of three tectonic conditions namely regional vertical uplift local basin subsidence and localised differential uplift the simulation results were compared against mapped terrace altitudes and deposit thicknesses the best results were achieved by combining all three tectonic factors indicating that specific terrace formation is a complex interplay of regional and local tectonics the best fit regional uplift rate of 0 10 m ka 1 over the past 600 ka is higher than the 0 08 m ka 1 previously estimated for a section farther to the west which can be attributed to an increase in tectonic uplift from the nw iberian atlantic margin toward the east local relative subsidence causes sediment accumulation in the local basin and less sedimentation in the fluvial terraces on the surrounding uplifting blocks different uplift rates on both sides of the valley caused preservation of unpaired terraces which are fill terraces on one side of the valley and strath terraces on the other side usually the formation of fill or strath terraces is considered to be only climate dependent our results indicate that local tectonics can be important in the terrace formation and preservation this suggests that terrace correlations in other river systems based on deposit thicknesses only might be over simplified

late cenozoic landscape development and its tectonic implications for the guadalhorce valley near alora southern spain abstract landscape evolution is the result of a variety of geomorphological processes and their controls in time in southern spain tectonics climate and sea level fluctuations have been some of the main variables controlling long term late cenozoic landscape evolution in the guadalhorce valley malaga geomorphological reconstructions can be undertaken using sedimentary evidence from marine and fluvial deposits as well as erosional evidence such as terrain form and longitudinal profile analysis data are obtained and analysed from the upper miocene to present these allow reconstructions which add information and constraints to the uplift history and landscape development of the area main sedimentation phases are the late tortonian early pliocene and pleistocene important erosional hiatus are found for the middle miocene messinian and late pliocene to early pleistocene these phases of erosion and sedimentation resulted in a relative large and elongated tortonian marine valley filled with complex sedimentary structures next a prolonged stage of erosion of these deposits and incision of the major valley system took place during the messinian in the pliocene a short palaeo guadalhorce in a narrow and much smaller valley existed this valley was partly filled with marine sediments and prograding fan delta complexes during the pleistocene a wider and larger incising river system resulted in rearrangements of the drainage network evaluating the uplift history of the area we found that rates of tectonic activity were higher during the tortonian messinian and upper pleistocene while tectonic activity was lower during the pliocene relative uplift rates for the study area range for the messinian between 160 and 276 m ma 1 for the pliocene between 10 and 15 m ma 1 and for the pleistocene between 40 and 100 m ma 1

sediment yield during late glacial and holocene periods in the lac chambon watershed massif central france a sediment budget for the late glacial and holocene periods was calculated for the lac chambon watershed which is located in a formerly glaciated temperate crystalline mountain area it appears that over 15 500 years 1 69 per cent of eroded particles have been displaced by gravity processes and then stored within the watershed compared to 31 per cent that have been displaced by running water and evacuated outward 2 the mean mechanical erosion due to gravity processes on the slopes amounted to 16 1 6 m and only developed on a quarter of the watershed surface whereas the mean mechanical erosion due to running water amounted 1 24 0 37 m and involved the whole watershed surface the mean sediment yields due to gravity processes on slopes were 2300 1360 1770 960 and 380 100 m 3 km 3 a 1 respectively for basalts and basic and acidic trachyandesites values of sediment yield due to running water were 49 15 120 36 and 79 24 m 3 km 2 a 1 respectively during the bolling allerod the younger dryas and the pre boreal boreal periods they were 56 17 and 166 50 m 3 km 2 a 1 during the sub atlantic period before and after 1360 a bp respectively these values reflect variations in the natural environment and the impact of human induced deforestation 1997 by john wiley sons ltd

climatically controlled river terrace staircases a worldwide quaternary phenomenon a comparison of fluvial terrace sequences from around the world based on data collected as part of international geoscience programme igcp project no 449 has revealed significant patterns river terraces provide important records of uplift which is essential for their formation and of landscape evolution their cyclic formation however almost invariably seems to have been a response to climatic fluctuation sequences in the european core area of igcp 449 which has the longest and most extensive research history have been used as templates for worldwide comparison there is evidence for a global acceleration of uplift at the time of and perhaps in response to the mid pleistocene revolution when climatic fluctuation switched to 100 kyr milankovitch cycles terraces formed prior to this generally consist of wide aggradational sheets that probably each represent formation over several 41 kyr cycles subsequently river valleys became more steeply entrenched and terraces formed in response to the stronger 100 kyr climatic forcing in many cases at approximately one per cycle this paper uses the new data resource to explore differences between records in different climate zones between sequences with variable numbers of middle late pleistocene terraces and between systems in which the all important incision event has occurred in different parts of climatic cycles key records discussed include european examples from the rhine thames somme dniester dnieper don volga and aguas from asia the gediz turkey and orontes syria from north america the south platte and colorado from south africa the vaal and sundays from australia the shoalhaven and from south america the amazon paraguay and tributaries of the colorado and negro