how do geomorphic effects of rainfall vary with storm type and spatial scale in a post fire landscape abstract in post fire landscapes increased runoff and soil erosion can cause rapid geomorphic change we examined how different types of rainfall events in 2013 affected hillslope scale erosion and watershed scale channel change in two 14 16 km 2 watersheds within the 2012 high park fire burn area in northern colorado usa the first set of rainfall events was a sequence of 12 short spatially variable summer convective rain storms and the second was a 200 mm week long storm in september we compared rainfall characteristics hillslope sediment yields stream stage and channel geometry changes from the summer storms to those from the september storm the summer storms had a wide range of rainfall intensities and each storm produced erosion primarily in one study watershed the september storm rainfall had less spatial variability covered both watersheds and its total rainfall depth was 1 5 to 2 5 times greater than the total summer rainfall because rainfall intensities were highest during some summer storms average hillslope sediment yields were higher for summer storms 6 mg ha 1 than for the september storm 3 mg ha 1 maximum storm rainfall intensities were good predictors of hillslope sediment yield but sediment yield correlated most strongly with total depths of rainfall exceeding 10 30 mm h 1 intensity thresholds the combined summer storms produced relatively small changes in mean channel bed elevation and cross section area with no clear pattern of incision or aggradation in contrast the sustained rain across the entire study area during the september storm led to extensive upstream incision and downstream aggradation because of different spatial coverage of storms summer storms produced more total hillslope erosion whereas the september storm produced the greatest total channel changes at both scales high intensity rainfall above a threshold was responsible for inducing most of the geomorphic change

eclogite blueschist relationships as evidenced by mineral equilibria in the high pressure metabasic rocks of sifnos cycladic islands greece

model for the evolution of the linear fold belt in the continents example of the urals abstract the following events of the well known wilson cycle are refined and amplified by results obtained mainly for the urals the uplift and diaschysis tectono magmatic activity protoorogenesis of the earth s crust were caused by upwelling of low density material in the upper mantle the diaschysis occurred long before or was occasionally partly contemporaneous with rifting accompanied by depression it is characterized by alkaline magmatites pseudostratified gabbro ultrabasite plutons and carbonatites features of recurrent diaschysis and rifting were recorded in mobile belts during several hundred millions of years they are occasionally terminated by complete lithospheric break up and formation of oceanic crust in other cases which were probably characteristic of the proterozoic the spreading and formation of oceanic crust did not take place due to rheological lithospheric stratification a brittle fracture of the upper ten kilometers of the earth s crust occurs simultaneously along two or more parallel fissures the subsequent separation of newly formed blocks and interblock basaltic magmatism lead to the production of microcontinents i e future median massifs of mobile belts the break up and separation of segments of continental lithospheric plates are followed by plastic extension at lower middle levels within the earth s crust this causes formation of different temperature blastomylonites and schists at about the same time there occur intrusions of granitoids into the extension zone and low moderate pressure zonal metamorphism until recently these phenomena were wrongly considered as indications of post geosynclinal orogenic regimes of inferred earlier geosynclinal cycles it might be suggested that the crust of the silurian ural ocean was almost completely subducted along the zavaritsky benioff zone dipping to the east in paleozoic back arc seas as well as in modern seas secondary spreading zones were present with abundant subvolcanic tholeiite volcanism the products of volcanism have suffered greenstone metamorphism as long ago as in pre orogenic oceanic island arc stage during formation of a mountain structure attended by development of granitoid magmatism there appeared to occur contrasting metamorphisms of sodic plagiogneiss schist complexes of a disthene series and a zone of glaucophane blastomylonites and subsequently potassic gneiss schist complexes of an andalusite series and disthene kalifeldspar blastomylonites geochemical backgrounds this metamorphism probably caused inner differentiation of crustal material repeated impulses of extension and outbursts of rifting occurred during the closure of oceanic structures and later in preorogenic and post orogenic stages

coupled barrier island resort model 1 emergent instabilities induced by strong human landscape interactions 1 as humans increasingly occupy and modify marginal landscapes previously unobserved long timescale emergent behaviors related to interactions between natural processes and human agency are possible barrier islands which are low lying strips of sand separated from a coast by lagoons cut by inlets and topped by sand dunes have been significantly modified through the development of tourist resorts resorts and barrier islands are dynamically coupled through storm damage and beach erosion and measures taken to prevent or mitigate them in response to rising sea level a natural barrier island migrates steadily up the continental shelf in contrast we show that in a novel numerical model coupling barrier island processes with resort development storm damage and hazard mitigation policy decisions driven by market dynamics destabilize barrier island response to rising sea level giving rise to emergent episodic boom and bust cycles which alternate in phase alongshore and less frequent regionally extensive resort destruction events developed barrier islands are precariously maintained at lower elevations and further offshore than their natural counterparts a situation exacerbated by insurance which can lead to island inundation our results suggest that coastal areas that have recently instituted protection measures eventually will experience a widespread upsurge in damage if these practices are sustained even in the absence of climate change induced increased storminess

investigating feedbacks in human landscape systems lessons following a wildfire in colorado usa abstract as human interactions with earth systems continue to intensify understanding the complex relationships among human activity landscape change and societal responses to those changes becomes increasingly important interdisciplinary research centered on the theme of feedbacks in human landscape systems serves as a promising focus for unraveling these interactions this paper examines the specific case of the 2012 waldo canyon fire of colorado where human responses after the fire to perceived threats of hydro geomorphological hazards included construction of tall fences at the base of a burned watershed these actions prompted feedbacks that promoted further landscape change that ultimately increased those hazards rather than dampening the hydro geomorphological effects of fire geomorphic analysis showed that the fences trapped particles that would naturally move through the system by flows with recurrence intervals greater than 3 3 years with the particles blocked by the fences the channel downstream became erosive because it was devoid of large particles that produce substantial hydraulic resistance channel incision prompted a second human response to pave the eroding channel which led to further incision downstream this cycle of positive feedbacks between human decision making and landscape change eventually led to a complete channelization of the stream channel downstream of the fences the explanation for the transformation of the post fire landscape therefore lies in the interacting human impacts and feedbacks rather than the expected post fire hydro geomorphological adjustments an initial agent based model capable of integrating social and hydro geomorphological data simulates these interacting impacts and feedbacks further refinement with more complete data input especially pertaining to human decision making at individual or local levels is required to fully demonstrate the utility and promise of this tool for application to geomorphic analysis

high pressure metamorphism in metabasites from the betic cordilleras s e spain and its evolution during the alpine orogeny the nevado filabride complex is the lowest tectonic unit of the betic zone sensu stricto ss of the betic cordilleras s e spain the upper series of this complex consists of a metamorphosed sequence intruded by basic and ultrabasic igneous rocks high pressure metamorphism in the eclogite and blueschist facies is recorded in the metabasites but this was partially obliterated by further successive metamorphic stages in the almandine amphibolite and greenschist facies

geomorphic processes and risk related to a large landslide dam in a highly urbanized mediterranean catchment genova italy abstract we present our research on the prato casarile landslide dam in genoa city to illustrate the interactions between slope instability processes and structural stabilization interventions aimed to reduce the hazard in a densely populated area analysis of the degradation of structural interventions constructed after flood events in 1953 1970 and 2014 contributed to an improved mitigation strategy at the same time the slope instability processes intensively advanced and regressive erosion quickly proceeded to the landslide dam threshold the discontinuity in human interactions in a geomorphic system after the initial hazard reduction resulted in an increased threat that combined with a rise in vulnerability due to urbanization expansion the research findings underline the necessity of constantly assessing the geomorphic evolution and active processes involved in order to determine the specific actions and interventions required to ensure the stability of the landslide dam finally and more generally we illustrated that anthropogenic interaction in the geomorphic system specifically when finalized for hazard mitigation needs to be continuously performed through both the monitoring and maintenance operation phases of the artificial structures

influence of large woody debris on channel morphology and dynamics in steep boulder rich mountain streams western cascades oregon this study used 20 year records of stream channel change and wood to test hypotheses about the long term influence of large woody debris lwd on channel morphology channel stability and sediment dynamics in a steep boulder rich mountain stream we compared two nearly adjacent reaches of third order mack creek over the period 1978 1997 after virtually all wood was removed from the channel of the lower reach in 1964 we assessed the long term legacy of wood removal using repeated crosssection surveys streamflow data lwd inventory data and detailed mapping and longitudinal profile surveys at each of 11 cross sections in the upper reach and 19 in the lower reach we calculated areas of scour and fill in response to the two largest floods in the record we used quasi likelihood logistic regression models to test the proportion of each reach that experienced change between consecutive surveys over the entire record 1978 1997 as a function of flood return periods the longitudinal profile of the site without lwd was more variable than the reach with lwd at the finest scale f1 m due to a greater frequency of boulder steps but the reach with lwd was more variable at the channel unit scale lwd created steps 1 to 2 5 m high in the wood rich reach accounted for nearly 30 of the total channel fall and created low gradient upstream channel segments one to three channel widths long as a result both reaches have the same average slope about 9 but nearly three times as much of the channel in the wood rich reach had a slope of v5 as in the reach without wood 20 4 of total channel length vs 7 5 of channel length the reach with abundant lwd was less responsive to moderate streamflow events return period f5 years but it responded similarly to peak flows with a return period of about 10 to 25 years although the average magnitude of crosssection changes was the same during the largest flood in the record 25 year return period the reach without lwd experienced scour and coarsening of the bed surface whereas the reach with lwd experienced aggradation upstream of lwd features mack creek may be representative of many steep mountain streams in which channel structure is strongly influenced by nonfluvial processes a legacy of large boulders from glacial or mass movement processes and a legacy of dead wood from ecological processes sediment limited mountain streams with large boulders when deprived of lwd appear to exhibit less morphological variation at the channel unit scale to store less sediment and to release it more readily than those with lwd d 2002 elsevier science b v all rights reserved

large woody debris and flow resistance in step pool channels cascade range washington abstract total flow resistance measured as darcy weisbach f in 20 step pool channels with large woody debris lwd in washington ranged from 5 to 380 during summer low flows step risers in the study streams consist of either 1 large and relatively immobile woody debris bedrock or roots that form fixed or forced steps or 2 smaller and relatively mobile wood or clasts or a mixture of both arranged across the channel by the stream flow resistance in step pool channels may be partitioned into grain form and spill resistance grain resistance is calculated as a function of particle size and form resistance is calculated as large woody debris drag combined grain and form resistance account for less than 10 of the total flow resistance we initially assumed that the substantial remaining portion is spill resistance attributable to steps however measured step characteristics could not explain between reach variations in flow resistance this suggests that other factors may be significant the coefficient of variation of the hydraulic radius explained 43 of the variation in friction factors between streams for example large woody debris generates form resistance on step treads and spill resistance at step risers because the form resistance of step pool channels is relatively minor compared to spill resistance and because wood in steps accentuates spill resistance by increasing step height we suggest that wood in step risers influences channel hydraulics more than wood elsewhere in the channel hence the distribution and function not just abundance of large woody debris is critical in steep step pool channels

urban transformation of river landscapes in a global context abstract over the past 50 years considerable progress has been made in understanding the impacts of urban development on river processes and forms such advances have occurred as urban population growth has accelerated around the world using a compilation of research results from more than 100 studies conducted in a range of areas 58 addressing morphological change this paper describes how urbanization has transformed river landscapes across earth s surface emphasizing the distribution of impacts in a global comparative context urban development induces an initial phase of sediment mobilization characterized by increased sediment production on the order of 2 10 times and deposition within channels followed by eventual decline that couples with erosion from increased runoff to enlarge channels data from humid and temperate environments around the world indicate that channels generally enlarge to 2 3 times and as much as 15 times the original size although research has emphasized temperate environments recent studies of tropical areas indicate a tendency for channel reduction resulting from strong sediment erosion and deposition responses because of intense precipitation and highly weathered soils embryonic research in arid environments further suggests variable river responses to urbanization that are characterized by rapid morphological change over short distances regardless of location the persistence of the sediment production phase varies from months to several years whereas several decades are likely needed for enlarging channels to stabilize and potentially reach a new equilibrium urbanizing streams pose particular challenges for management given an inherent changing nature successful management requires a clear understanding of the temporal and spatial variations in adjustment processes

blueschists and eclogites a possible plate tectonic mechanism for their emplacement from the upper mantle the most significant problem of blueschists and eclogite origin is explaining the mechanism by which they were transported from great depths to the surface three aspects of this problem are discussed 1 1 prograde and retrograde trajectories in blueschist and eclogite bearing belts and the preservation conditions for such minerals as aragonite lawsonite and coesite 2 2 the mechanism by which low density crustal rocks with coesite and diamond descend to a depth of 100 150 km and the high rate of return from these depths to the surface 3 3 the origin of a tectonic mixture of rocks from different depths in melange zones using estimations of p t conditions and constructed p t t trajectories four types of blueschist belt are proposed these include two of the ernst types the alpine and franciscan and two additional types the dora maira and sanbagawa types key examples of geologically and mineralogically well studied complexes in the soviet union are discussed the kokchetav massif maksutov complex syumkeu belt borus belt the various models for the origin of different types of high pressure metamorphic belts are considered 1 1 slow uplift or uplifting of the thickened crust after cessation of subduction 2 2 more rapid tectonic pushing out 3 3 the same as in case 2 but with an additional champagne cork effect 4 4 the most complicated process with repeated deformation and metamorphism

heat flow variations from bottom simulating reflectors on the cascadia margin abstract a bottom simulating reflector bsr representing the base of the gas hydrate stability field was observed over a closely spaced grid of seismic lines on the continental slope of the northern cascadia margin a simple conductive model was used to calculate heat flow from the depth of the bsr a regional trend was observed in which heat flow decreased landward across the margin from an average of 80 mw m2 at a distance of 15 km from the deformation front to 65 mw m2 at a distance of 40 km this trend reflects the processes of tectonic thickening of accretionary wedge sediments and subduction of the juan de fuca plate and contrasts with the near constant heat flow across the oregon margin where the dip of the subducting plate and thus the rate of sediment thickening are slightly smaller consistent local variations were also observed notably low heat flow values over prominent topographic highs and high heat flow values over the flanks of the topographic highs at some localities over a horizontal distance of 1 2 km heat flow increased by as much as 50 from typical values of 65 to 100 mw m2 much of this variation may be due to focusing and defocusing effects of the topography alone and indicates the importance of carrying out topographic corrections to heat flow in regions of significant relief such as the continental slope however a component of the local heat flow patterns may be due to dynamic effects including the displacement of isotherms by thrust faulting and the upward migration of warm fluids along permeability channels such as faults

the natural and human structuring of rivers and other geomorphological systems a tribute to william l graf this special issue honors the contributions of william l graf to geomorphology and river science a hallmark of will s work over the course of his career has been a focus on the natural and human structuring of river systems more broadly will has been an innovator and leader who has shaped the way in which geomorphologists conduct research through his work he has made fundamental contributions to basic fluvial theory to the understanding of human impacts on river systems and to policy relevant science he has demonstrated by example how to pursue policy relevant science and to participate in science based policy formulation his contributions to river science can be classified into several themes 1 the hydrology and geomorphology of suburban drainage systems 2 riparian vegetation and river systems 3 the spatial structure and dynamics of incised channels 4 the dynamics of dryland river systems 5 heavy metals in river systems 6 dams and dam removal and 7 water and public policy the papers in this special issue reflect many aspects of these themes and address topics related to 1 the understanding of rivers and other geomorphic systems in the midst of dynamic physical change 2 human influences on geomorphic processes 3 the intersection of geomorphology and public policy and 4 the fusion of geomorphic analysis and giscience

phase relationships and p t conditions of coexisting eclogite blueschists and their transformation to greenschist facies rocks in the nerkau complex northern urals abstract eclogites and blueschists coexist in the same lithologic sequence in the nerkau complex one of the metamorphic complexes in the northern urals russia two types of eclogites can be distinguished in this complex 1 glaucophane free eclogites consisting of garnet omphacite barroisite calcic amphibole albite epidote rutile titanite quartz in these rocks phase compatibilities indicate that barroisite was stable at eclogite conditions together with garnet and omphacite this assemblage was overprinted by another consisting of barroisite mg hornblende albite epidote which developed under albite bearing greenschist conditions 2 paragonite glaucophane bearing eclogites consist of omphacite garnet glaucophane barroisite actinolite paragonite albite epidote titanite rutile quartz textural and chemographic analyses indicate that two main metamorphic episodes took place as well represented by the assemblages omphacite garnet glaucophane and barroisite albite chlorite respectively the blueschists surrounding the eclogites consist of garnet glaucophane barroisite phengite paragonite chlorite albite quartz titanite rutile ilmenite phase relationships indicate that no reaction relates eclogites with blueschists and that both mineral assemblages can be stable at the same metamorphic conditions the occurrence of these assemblages side by side could thus be controlled by the bulk rock composition metamorphic conditions have been calculated for each lithology with different but complementary methods the two types of eclogites were stable between 450 and 490 c or 500 and 537 c depending on the thermometer used and minimum pressures of 10 to 11 kbar these values compare favourably with 530 20 c and 14 5 1 kbar obtained with a p t diagram calculation and a forward modelling approach in the case of blueschists coexisting glaucophane and garnet are stable at similar metamorphic conditions the final retrogressive transition to greenschist took place at p below 9 kbar and t around 480 c this results in an almost isothermal decompressional path

metamorphism and phase relations in carbonate rocks from the nevado filabride complex cordilleras beticas spain application of the ttn rt cal qtz gr buffer phase relations and metamorphic conditions have been studied in metacarbonate rocks from the nevado filabride complex cordilleras beticas through forward modeling in many rock samples the assemblage titanite rutile calcite quartz graphite buffered the composition of the c o h fluid present during metamorphism over a wide range of p t conditions fluid compositions computed for this buffer are essentially binary h2o co2 mixtures this buffer also constrains the chemical potentials of tio2 cao and sio2 consequently it is possible to make a thermodynamic projection through these components to predict the stable phase relations consistent with the buffer using this method phase relations have been analyzed in a rock containing the buffer assemblage and paragonite albite phengite epidote and chlorite the equilibrium p t conditions for this assemblage are constrained by minimization of the differences between predicted and observed mineral compositions to be 560 15 c and 9 5 1 kbar conditions obtained compare well with those estimated from other studies in different lithologic units the inferred metamorphic fluid composition is h2o rich

the long term control of vegetation and woody debris on channel and flood plain evolution insights from a paired catchment study in southeastern australia abstract numerous case studies have demonstrated that alluvial and semi alluvial rivers in se australia have undergone dramatic metamorphosis in historical times however very few studies place these changes within a long term evolutionary context as a consequence the magnitude of and ultimate controls on the changes to river form and processes are not fully appreciated in this study a paired catchment analysis is undertaken between two moderate sized sand bed rivers in east gippsland australia from the thurra river direct insight is gained into the predisturbance control exerted by riparian vegetation and wood in a lowland alluvial river this river is effectively in the same condition today as it was at the time of the arrival of europeans in australia in contrast the adjacent cann river which has been settled by europeans for 150 years but was previously very similar to the thurra river exhibits stark differences today channel morphodynamics observed within the thurra river when coupled with historical and geomorphic evidence for the former condition of the cann river provide a detailed reference by which the recent changes to the cann river are measured chronostratigraphic evidence from both flood plains places recent channel behavior within an evolutionary context extending well into the pleistocene since european settlement the study reach of the cann river has experienced a 360 increase in channel depth a 240 increase in channel slope a 700 increase in channel capacity and up to a 150 fold increase in the rate of lateral channel migration the contemporary condition of the cann river channel differs profoundly to that which has prevailed over at least the previous 27 ka the first order control on the historical channel metamorphosis is the removal of riparian vegetation and woody debris wd numerous thresholds have been crossed as a result of historical channel changes particularly the relationship between average length of woody debris pieces and channel width consequently channel recovery will not simply be achieved by reintroducing the pre existing riparian vegetation and woody debris load devising sound management strategies and realistic management targets for the cann river or any similarly altered river requires an understanding of the long term channel and flood plain evolutionary history as well as the underlying controls on historical changes

the morphologic structure of step pools in mountain streams abstract step pool sequences in streams in the santa monica mountains of southern california impart a characteristic morphologic structure that varies with slope but despite the strong association with slope that suggests a direct process control analysis of 464 step pools in 13 study reaches reveals the relationship to reflect correlation but not necessarily causality the direct control on step height is particle size whereas discharge is the probable causal process determining step wavelength because both particle size and discharge generally change with channel slope downstream a slope variation with step wavelength and height is the apparent indirect geometric result a conceptual model of process form linkages is proposed based on these results whereby the step pool morphology is produced by positive relationships between wavelength and discharge and between height and particle size the model offers new insights for explaining the step pool morphology and it is potentially useful in channeling future efforts toward the appropriate scales and variables

coexisting amphiboles in an eclogite from the western alps new constraints on the miscibility gap between sodic and calcic amphiboles crystal chemical relationships between coexisting sodic and calcic amphiboles have been studied in eclogitic metagabbros from the aosta valley western alps textural analysis gives evidence of three successive high pressure parageneses 1 pre kinematic high grade blueschist assemblages preserved as polymineralic inclusions in garnet cores and made of glaucophane and actinolite stage a 2 synkinematic eclogite assemblages composed of garnet omphacite glaucophane actinolite white mica clinozoisite quartz rutile stage b 3 post kinematic epitactic overgrowths of barroisitic amphibole on glaucophane and actinolite stage c p t conditions of the eclogitic metamorphism have been estimated at around 500 550 c 16 kbar glaucophane and actinolite coexist as discrete grains in stage a and b assemblages this texture and the chemistry of the amphiboles unambiguously denotes the existence of a miscibility gap between sodic and calcic amphiboles from nam4 0 80 in actinolite to nam4 1 70 in glaucophane at t 500 550 c a comparison with published analyses allows a new solvus along the glaucophane actinolite join to be drawn the later barroisitic amphibole stage c exhibits strong chemical zonation indicating disequilibrium growth this amphibole cannot either be used to define a miscibility gap with glaucophane or actinolite or be considered as an intermediate stage between these two end members

disturbance stream incision and channel evolution the roles of excess transport capacity and boundary materials in controlling channel response abstract channel incision is part of denudation drainage network development and landscape evolution rejuvenation of fluvial networks by channel incision often leads to further network development and an increase in drainage density as gullies migrate into previously non incised surfaces large anthropogenic disturbances similar to large or catastrophic natural events greatly compress time scales for incision and related processes by creating enormous imbalances between upstream sediment delivery and available transporting power field examples of channel responses to antrhopogenic and natural disturbances are presented for fluvial systems in the mid continent and pacific northwest usa and central italy responses to different types of disturbances are shown to result in similar spatial and temporal trends of incision for vastly different fluvial systems similar disturbances are shown to result in varying relative magnitudes of vertical and lateral widening processes and different channel morphologies as a function of the type of boundary sediments comprising the bed and banks this apparent contradiction is explained through an analysis of temporal adjustments to flow energy shear stress and stream power with time numerical simulations of sand bed channels of varying bank resistance and disturbed by reducing the upstream sediment supply by half show identical adjustments in flow energy and the rate of energy dissipation the processes that dominate adjustment and the ultimate stable geometries however are vastly different depending on the cohesion of the channel banks and the supply of hydraulically controlled sediment sand provided by bank erosion the non linear asymptotic nature of fluvial adjustment to incision caused by channelization or other causes is borne out in similar temporal trends of sediment loads from disturbed systems the sediments emanating from incised channels can represent a large proportion of the total sediment yield from a landscape with erosion from the channel banks generally the dominant source disturbances that effect available force stream power or flow energy or change erosional resistance such that an excess of flow energy occurs can result in incision channel incision therefore can be considered a quintessential feature of dis equilibrated fluvial systems

catchment scale cumulative impact of human activities on river channels in the late anthropocene implications limitations prospect abstract evidence for the proposed anthropocene epoch in fluvial geomorphology hinges on the influence of human activities relative to natural forcing however research on cause effect understanding in river channel evolution has rarely focused on the cumulative impact of multiple drivers for change limiting insights systematic review of 25 recent studies professing to explain reach scale channel responses to cumulative impacts of human activities and natural forcing over the recent past ca 1880 2005 reveals some consistencies in spatio temporal response across various catchment sizes median 3000 km2 in mostly industrialized nations common drivers for change include changing flood and flow regimes dam construction changing land uses and forest cover bank protection and instream aggregate mining recent channel evolution has predominantly involved narrowing incision and terrace development reduced bed sediment storage lower activity rates and simplified channel geometries rates of channel change frequently peaked 1955 1990 providing some support for the anthropocene great acceleration evidence here suggests that many river systems are now in morphologically novel configurations coinciding temporally with dramatic recent declines in global freshwater aquatic biodiversity sustainable approaches to freshwater management must acknowledge these configurations placing emphasis on process based approaches to river ecosystem health in which sediment cascades are reconceived to reflect altered longitudinal and lateral connectivity however the reviewed studies are driven largely by expert judgment depicting cause effect associations through summary conceptual models based on spatial proximity and temporal synchronicity providing insufficient scientific proof for the anthropocene based on the overwhelming impact of human factors more conclusive cause effect statements will require hypothetic deductive approaches explicit functional criteria and best practice environmental model building geomorphologists should now move beyond the phase of discovery and develop rigorous proofs for cause effect relationships of cumulative impact this may be enhanced by developing an avowedly anthropocene perspective in which rivers are viewed critically as socio biophysical systems co evolving with human activity