the resilience of a badland area to climate change in an arid environment badlands have long been considered as model landscapes due to their perceived close relationship between form and process the often intense features of erosion have also attracted many geomorphologists because the associated high rates of erosion appeared to offer the opportunity for studying surface processes and the resulting forms recently the perceived simplicity of badlands has been questioned because the expected relationships between driving forces for erosion and the resulting sediment yield could not be observed further a high variability in erosion and sediment yield has been observed across scales finally denudation based on currently observed erosion rates would have lead to the destruction of most badlands a long time ago while the perceived simplicity of badlands has sparked a disproportional compared to the land surface they cover amount of research our increasing amount of information has not necessarily increased our understanding of badlands in equal terms overall badlands appear to be more complex than initially assumed in this paper we review 40 years of research in the zin valley badlands in israel to reconcile some of the conflicting results observed there and develop a perspective on the function of badlands as model landscapes while the data collected in the zin valley clearly confirm that spatial and temporal patterns of geomorphic processes and their interaction with topography and surface properties have to be understood we still conclude that the process of realizing complexity in the simple badlands has a model function both for our understanding as well as perspective on all landscape systems

direct and indirect evaluation of denudation rates in central italy abstract this paper presents the main results of a series of geomorphological studies aimed to the quantitative direct and indirect evaluation of denudation processes in central italy these studies which started in some sample areas since long ago were further deepened and extended to a wider number of drainage basins representative of a variety of morphostructural conditions the complex cause effect relationships among factors influencing both the morphogenesis and the plano altimetric configurations of drainage basins resulted in a large variability in the values of the denudation index tu which ranged from 200 to 2500 t km2 year very high values tu 10 000 t km2 year were obtained for small catchments belonging to the wider basins of ombrone river and tevere river where fast morphological modifications occur due to the action of surface running waters and gravity in the drainage basins affected by the most powerful denudation processes direct measurements of denudation were performed several monitoring stations were equipped with iron stakes and disks to record the local modifications of the topographic surface with time whereas some of these stations have been working continuously since 1993 some others have been running only periodically direct measurements pertinent to periods longer than a decade indicated that mean annual values of denudation range between 1 and 2 5 cm year for slopes affected by sharp edged and or rounded edged badlands higher denudation rates 3 4 cm year were obtained for shorter observation periods still higher rates were recorded for short periods at the gully bottom or in coincidence with mass movements before bench marks were turned up or damaged denudation processes are likely to occur discontinuously they show a step like trend with time and are triggered by rainfall events distributed over a number of consecutive days though not greatly intense particularly their amount should overcome the threshold of 60 mm per 5 consecutive days below this threshold the surface runoff does not seem to reach the power necessary to induce significant modifications of the topographic surface in the study area

quantitative assessment of the piping erosion susceptibility of loess derived soil horizons using the pinhole test abstract the pinhole test is an empirical test based on the qualitative evaluation of the dispersivity colloidal erodibility of compacted fined grained soils this paper evaluates the pinhole test device for the quantitative assessment of the susceptibility of soil horizons to piping assesses the effects of hydraulic head water quality antecedent soil moisture content and soil disturbance on the hydrological and erosion response during pipeflow and formulates recommendations for the application of the pinhole test to study piping erosion processes in total 255 pinhole test experiments were conducted the results obtained from disturbed soil samples ap horizon indicate i a significant positive linear increase in pipeflow discharge qw and sediment discharge qs with increasing hydraulic head ii no relationship between qw and antecedent soil moisture content asm but significant and negative relationship between qs and asm and iii significantly higher qs for distilled water than for tap water the use of disturbed soil samples resulted in significantly more rapid flow responses and lower sediment discharges than for undisturbed soil samples the pinhole test experiments performed on different loess derived soil horizons show that the plowed topsoil ap and the underlying clay enriched horizon bt are at least two times less susceptible to piping than the decalcified c1 and the calcareous horizons c2 this confirms field observations indicating that loess derived soil horizons are very susceptible for piping erosion especially when the c horizon crops out this study demonstrates that the pinhole test is suitable for assessing the susceptibility of soil horizons to piping in a quantitative way i e qw qs the time to outflow and the cross section of the pipe after the test we recommend the use of i two different hydraulic heads i e 180 and 1020 mm ii distilled water iii contrasting antecedent soil moisture contents of the soil samples to be tested and iv different soil sampling methods to investigate the effect of soil disturbance and particularly to obtain a better understanding of the sediment response during pipeflow

identification of calanco a badland landform in the northern apennines italy calanco plural calanchi is a term widely used in the northern apennines italy to define a type of badland formed in clayey bedrock however no precise geomorphological definition of calanco has been established and a variety of map symbols are used to indicate the presence of calanco landforms with the aim of developing an improved approach to identifying calanchi a group of experienced surveyors identified 24 catchments with calanco characteristics among 67 catchments located between bologna and faenza in the northern apennines the morphology of each catchment was classified using traditional quantitative geomorphic approaches including fieldwork map interpretation hypsometric curve construction and computation of the annual sediment yield consideration of the parameters produced by these approaches indicated that none was capable of representing the presence of calanchi unequivocally and the basins were grouped into five classes on the basis of number and type of calanco criteria that they met a characteristic of calanchi that is evident on topographic maps is crenulation of the contour lines and in this study a new topographic parameter was developed to represent the degree of contour crenulation this parameter lo lf is defined as the ratio of the actual length of a contour line lo to the length of the same line smoothed by an algorithm based on a moving average lf calculated values of lo lf ranged from 1 05 to 1 38 to test whether high values of the contour crenulation parameter were associated with calanchi lo lf values were added to other criteria for the five classes of catchment class 1 catchments consisting of 14 of the 24 calanchi catchments identified in the field displayed all of the criteria defining calanchi and were characterized by the highest values of lo lf mean value 1 27 0 15 it is proposed therefore that the contour crenulation ratio lo lf may be useful in identifying the calanco landform copyright 2000 john wiley sons ltd

high rates of erosion and rapid weathering in a plio pleistocene mudstone badland taiwan abstract the badlands of southwest taiwan are characterized by sharp ridges and are located in a tropical monsoon area that experiences contrasting rainy and dry seasons surface erosion predominates and subsurface erosion by piping is rather limited to accumulation of mud in valley bottoms erosion rates on plio pleistocene mudstone slopes measured using erosion pins over a period of 4 years averaged up to 9 cm y which is considerably faster than the rates of a few cm y typical in arid or semi arid areas mudstone sample cores recovered from the slopes in the dry season april and in the early rainy season july prior to the extensive erosion that occurs later in the rainy season suggested the following mechanism for weathering and erosion near surface layers

factors underlying piping in the basilicata region southern italy abstract piping tunnelling erosion is a widely spread process in the plio pleistocene marine clays of the basilicata region in southern italy the pipes are often closely concentrated along the surface drainage networks at different depths with a tunnel length and a diameter varying from just a few centimetres to some metres the formation and evolution of pipes in the badlands can be explained through 1 geo structural characteristics of the clay 2 material properties such as a high exchangeable sodium percentage 3 favourable climatic conditions and 4 hydraulic gradient along the path controlled by the gully or ravine bottom that is acting as a local drain the exposure and the extension of joints at the surface and in the bedrock along the slope are the main factors required for development of the pipes the absence of the piping erosion on the slopes where a reasonably thick layer of the soil material covers the open joints shows that although certain material properties and climatic conditions play an important role they are not sufficient to develop extensive piping erosion in the area

morphological analysis and erosion rate evaluation in badlands of radicofani area southern tuscany italy abstract since 1988 geomorphologic research based on field surveys and photo geological analysis has been conducted in southern tuscany italy in areas characterised by very rapid morphological evolution in the area outcrop pliocene marine claystones uplifted during the quaternary up to 750 m above sea level now undergoing intense erosion processes leading to considerable badlands formation morphodynamic analysis conduced by direct and indirect measurements in a sample area were taken in order to quantify the erosion rate in badland areas the torrente piantrafolla sample area was chosen as representative of the study area it was most recently monitored during the period nov 2000 feb 2004 at this time morphographic and morphometric analyses carried out in selected measurement stations located on slopes identified gravity as the main morphogenetic process responsible for slope shaping the calanchi badland areas are characterised by constant and rapid shrinking of their edges resulting from landslides which occur in autumn and winter as a consequence of intense rainstorms selected measurement stations indicate an erosion rate value range from 5 to 7 5 cm y the comparison between 1976 and 1994 digital elevation models dem obtained from photogrammetric restitution indicated a mean erosion rate of about 5 cm y in a nineteen year period this value considerably higher than the values measured in other italian basins indicate a very rapid evolution of the slopes due mainly to small earth flows inside calanchi badlands

gully and tunnel erosion in the hilly loess plateau region china article i nfo article history although gully development is frequently observed to be associated with piping and tunnel erosion in many parts of the world there is a lack of detailed studies on their spatial interactions such studies not only con tribute to developing geomorphic theories on the evolution of both hillslopes and drainage networks but also are useful to design effective control measures of erosion the present study aims to examine the interactions between gully development and tunnel erosion in the hilly loess plateau region of northern china firstly gullies tunnel inlets and mass movements in the 9 1 km 2 wangjiagou watershed were mapped through ae rial photo interpretation and reconnaissance surveys secondly detailed field studies were carried out to in vestigate the interactions between gully development and tunnel formation processes in the selected gullies thirdly the physiographic variables of gullies derived from gis and field measurements were analyzed to identify differences between tunneled and untunneled gullies a total of 704 channels 967 tunnel inlets and 547 mass movements were identified in the study watershed on the basis of their location and morphology all the channels were classified into four types headwater gullies hillside gullies valleyside gullies and ephemeral river channels tunnels are associated with 79 of headwater gullies 48 of hillside gullies 3 of valleyside gullies and none of ephemeral river channels mass movements are dominated by falls in headwater gullies falls and slides in hillside gullies and soil creeps in ephemeral stream channels statistical tests indicate that there are significant differences in phys iographic variables between tunneled and untunneled gullies tunnel formation in gullies is intricately affect ed by topographic conditions land uses knickpoint distribution soil materials and mass movements published by elsevier b v

structural controls on the orientation of erosion gullies in mid western new south wales australia abstract the role of geology in determining the drainage network of gullying has been evaluated by quantitative methods of analysis at gully erosion sites in new south wales field evidence suggests that soil cracks are sites of preferential flow and erosion at both the surface and subsurface soil fabric and rock structure and weathering studies were undertaken to establish the inheritance of soil cracks from the underlying parent material gully orientation was correlated with the strike of joints and bedding planes in a range of rock materials including sedimentary intrusive and extrusive igneous and thermal and regional metamorphic rocks these units vary not only in terms of mineralogy but also in degree of weathering however all are steeply dipping structures usually exceeding 60 correlations exist between gully orientation and joints in the underlying material but the strength of the relationship varies according to the parent material in the ordovician hornfels where no correlation between joints and gully orientation occurred the evidence showed that gullying was controlled by faulting along the hornfels granite boundary these relationships support the view that throughflow processes are dominant in the development of gullies since convergence of runoff would not be expected to align with subsurface soil discontinuities

space time variability of denudation rates at the catchment and hillslope scales on the tyrrhenian side of central italy studies on denudation rates can provide insight into the influence of climate change tectonics and human activities on landscape evolution research performed in central italy has shown considerable spatial variability of denudation rates in the major river basins these studies have focused mainly on the tyrrhenian side of the italian peninsula where plio pleistocene marine deposits filling nw se elongated sedimentary basins have been uplifted during the quaternary up to several hundreds of meters above present sea level small sub catchments developed on clays are affected by sharp and or rounded edged badlands i e calanchi and biancane representing denudation hot spots in the present day morphoclimatic framework in this paper we analyze the relationships between indirectly estimated denudation rates at the catchment scale and field monitoring data at the hillslope scale we attempt to better understand and quantify all hillslope processes that contribute to seasonal variability of denudation to help with predicting the net input from hot spots to the overall estimated sediment yield at the basin outlets at the hillslope scale we discuss in particular the variability of denudation rates at calanchi and biancane badlands as a function of their different morphoevolution

statistical analysis of the geological hydrogeological conditions within part of the eye dashwa pluton atikokan northwestern ontario the occurrence and distribution of fracture filling material within the eye dashwa granite indicate that the dominant fracture system formed shortly after emplacement and cooling of the pluton at 2678 f 67 ma subsequent reactivation of these ancient fractures was accompanied by sequentially younger and lower temperature filling materials these reopened ancient fractures are best developed in the upper 300 400 m of the rock mass and are commonly conduits for present day groundwater flow multiple linear regression analysis performed on the geological variables defined from boreholes atk 1 2 3 4 and 5 identified a highly significant correlation between a number of these variables and hydraulic conductivity values measured in 25 m test sections of the boreholes the correlation is expressed as where log kern is the log of hydraulic conductivity log depth is the log transformed depth to the lower end of the packer interval log clay is the log transformed frequency of clay filled fractures per 25 m interval log ve1n is the logtransformed frequency of veins per 25 m interval the equation has a multiple r value of 0 82 explains 67 of the variance of hydraulic conductivity and has a random exceedence probability q of 9 x 10 l2 i e it is highly significant the predictive capability of the regression design was tested with seven new test data and found to be a valid estimator of the hydrogeological conditions within these test intervals

msi morphometric slope index for analyzing activation and evolution of calanchi in italy article i nfo the calanchi singular calanco are a typical example of italian badlands widespread in areas with hills of clay rich sediments and rocks they appear as a very dense and rapidly evolving drainage system characterized by an alternating pattern of narrow furrows and sharp crests the calanchi can be considered as small hydrographical basins characterized by two possible drainage patterns parallel and dendritic the two patterns show both linear and areal erosion processes in this study calanchi with dendritic drainage patterns were analyzed in three different areas representative of the italian peninsular atri in the abruzzi region mount ascensione in the marche region and orcia valley in the tuscany region for each calanchi the pre erosion topographic surface was reconstructed and the value of msi morphometric slope index was calculated for the surface the volume of eroded material was estimated by comparing the pre calanchi and present surfaces we assumed that slope morphometry influences the type of erosion processes and the efficacy of these processes with respect to the amount of eroded material is a func tion of their duration we deduced that calanchi inception was contemporaneous because the duration of the processes was common to all landforms and probably due to a common climate input moreover the relations among msi eroded volume and erosion processes indicate that over a long period areally distributed surface processes contribute more to total sediment yields than channel flows

spatial variation of bed roughness in eroding rills and gullies when overland flow concentrates rill and gully channels can be formed if a series of thresholds are exceeded these thresholds are more or less explicitly linked to the erosion resistance of the topsoil moreover flow velocity and channel width depend on total flow discharge more recently also bed roughness in eroding channels has been attributed to the eroding effect of flow discharge while channel width was shown to be the result of the interplay between erosion resistance of the topsoil and flow discharge see channel junction approach torri et al 2006 which could be described by a modified leopold and maddock s relationship the objective of this paper is to investigate the spatial variability of channel bed roughness in rills and gullies using an approach based on these findings field data confirm the various aspects reported so far hence these were used to develop a new equation allowing one to predict bed roughness in eroding rill and gully channels each of the new aspects introduced into the channel width flow discharge equation by the channel junction approach is discussed and verified with new data the validity of this approach is tested against channel data from mars finally an equation predicting bed roughness and based on stream power is developed and compared with measured rill and gully bed roughness successfully confirming that 1 bed roughness if generated by concentrated flow increases with stream power 2 channel width local bed slope topsoil cohesion at saturation and grain size are all important factors controlling channel bed roughness and 3 these variables as well as soil characteristics all measurable in the field after a rill or gully forming event are sufficient to determine channel bed roughness therefore one may expect that bed roughness of an eroded channel and consequently hydraulic roughness or friction will generally increase with bed gradient erosion resistance of the soil and grain size following a logic which is best expressed by the final equations described in this paper

the role of the hillside in determining the morphometric characteristics of calanchi the example of adriatic central italy abstract a typical example of badlands in the italian peninsula is the calanchi plural of calanco which may be defined as rapidly evolving very dense and hierarchical drainage systems whose genesis is controlled by mineralogical characteristics the granulometric composition of local lithotypes structural conditions hillside gradient and climate in this work some of the morphometric characteristics of the hillside were compared on a statistical basis with those of the drainage network of the calanchi for two large sample areas in adriatic central italy it was possible to demonstrate how the hillside environment strongly affects the activation of the process and the characteristics of the calanchi depending on their morphometric morphometric characteristics in particular the length inclination ratio of the hillside conditions the hydrographic pattern of the calanco system

a typical calanchi landscape on the eastern apennine margin atri central italy geomorphological features and evolution abstract the surroundings of the town of atri abruzzo region central italy situated about 10 km from the adriatic shoreline can be considered as representative of most part of the italian seaward peninsular landscape the subject of this research the calanchi landscape often generally considered as badlands by non italian authors is in fact made up of many singular landforms each of which calanco corresponds to a more or less extended hydrographic unit the dynamics are mainly the result of the action of the particularly aggressive climatic factors such as the mediterranean rainfall regime on weak substrata clay silt and sand of the plio pleistocene marine cycles the morphogenetic activity is not only limited to channel erosion but it is also due to repeated superficial slides so that it should in fact be better to consider the calanco as the result of a combined erosion process sensu zachar d 1982 soil erosion elsevier amsterdam since the mechanism regulating this process remains unclear this work wants to offer a contribution to this research field multitemporal geomorphological analysis has helped us to distinguish the different areas in which the calanchi evolution has been more or less important in the past in such a way it has been possible to characterize the landscape evolution as a function of the parameters that influence soil loss especially in areas such as that of atri where calanchi like landforms are highly developed moreover this analysis coupled with the processing of 40 years rainfall data also taking into account the concurrent land use changes has clearly shown that the areas affected by calanchi erosion on the eastern apennine margin still tectonically active are progressively diminishing

the ages of fractures in the eye dashwa pluton atikokan canada ages of fractures in the eye dashwa granite pluton north of atikokan ontario are estimated from analyses of their filling materials pegmatite aplite hornblendeporphyry epidote chlorite gypsum diabase iron oxides carbonate and clays the analyses include radiometric age determinations of filling materials comparison of crystallization temperatures of filling materials with the expected temperature of the pluton through time and paragenetic relations derived from textures the major fractures primarily epidote and chlorite filled were produced by penetrative deformation during cooling immediately after intrusion of the pluton from 2 6 ga to 2 4 ga they transected the pluton and largely defined the present overall fracture network less severe penetrative deformation occurred about 1 1 ga when a few diabase dikes and small gypsum fractures developed a second source of fracturing appears to have existed through most of geological time and it reopened segments of old fractures within about 400 m of the present erosional surface it is unknown whether the near surface or supergene fractures formed more or less continuously through time or in distinct episodes such as during glacial periods open fractures which are most common in the near surface layer tend to transmit groundwater but fracture sealing due to the accumulation of filling materials seems to occur with time underground excavations such as nuclear fuel waste disposal vaults would be less susceptible to the incursion of groundwater if they were located below the near surface layer

effects of land use changes on badland erosion in clayey drainage basins radicofani central italy abstract hillslopes of the radicofani area in the upper valley of the orcia river southern tuscany region italy consist mainly of early pliocene clayey sediments and are widely affected by frequent badland erosion reforestation with frugal conifers has been carried out in the area over the last 50 years the goal of the present study is to evaluate the impact of reforestation and land use change on erosion rates in nine small drainage basins through a multidisciplinary approach geological geomorphological hydrological and land use characteristics were analyzed by a diachronic confrontation between pre reforestation 1954 and post reforestation 2007 situations aerial photo interpretation and processing in gis allowed us to quantify changes in areas affected by badland erosion land use and variations in erosion rates moreover dendrometric data were gathered from 18 circular sample plots in forest stands of 40 years old this allowed us to evaluate both the adaptability of different forest species to the clayey substrate and reforestation fragmentation the differences between the pre and post reforestation situations led to increases in arable land and forest areas and considerable decreases in erosion rates and badland areas however no significant correlation between the erosion rates and the forest area emerged due to the excessive fragmentation of reforestation cores and relatively small reforested surfaces land reclamation seems to have played a more important role in reducing erosion in the clayey substrate the integrated method presented here is an important tool useful to understand the morphological dynamics of badlands in relation to forest vegetation and for land planning and management

detachment and infiltration variations as consequence of regolith development in a pyrenean badland system the araguas experimental catchment has been monitored to study badland dynamics in the central pyrenees previous studies of weathering processes within the catchment reported strong regolith dynamics associated with seasonal variations in the temperature and moisture regimes a preliminary analysis of hydrological response and suspended sediment transport data recorded at a gauging station also demonstrated seasonal trends the main objective of the present study is to understand the effect of regolith dynamics on sediment detachment and infiltration processes based on field studies using simulated rainfall the experiment design was based on seasonal differences in the physical conditions of surface regolith and the general trends of hydro sedimentological responses rainfall simulations were conducted on small plots using a pressure nozzle similar experimental rainfall conditions were set for all plots rainfall intensity around 45 mm h 1 the results showed strong variations in the infiltration and detachment responses closely associated with the regolith conditions and crusting development infiltration showed seasonal differences in time lag and intensity average infiltration rates ranged from very low 2 05 mm h 1 to moderated high values 44 04 mm h 1 associated to regolith development conditions maximum sediment concentration as an indicator of particles produced by detachment also ranged from moderate 3 g l 1 to extreme values 145 g l 1 mean and minimum infiltration rates showed negative correlations with initial moisture content sediment concentration showed a positive correlation with time lag ponding and sealing time and a negative correlation with initial moisture in terms of seasonal trends infiltration and erosion responses were relatively stable during spring and autumn whereas wide variations were recorded in infiltration rates and sediment detachment during summer and winter as a general conclusion the obtained results indicate that seasonal differences in detachment and infiltration depend on the nature of regolith development copyright 2009 john wiley sons ltd

a diagram for interpreting orientation data for planar features in core abstract a new type of diagram depicts orientation data for planar structures found in drill core strike and dip of fractures intersected by a borehole are plotted independently side by side as a function of borehole length these companion plots show variations in distribution and orientation of fractures the diagram is used to establish boundaries between fracture domains and to interpret a sequence of fracturing based on the spatial relationship between domains comprising different fracture patterns

micropiping processes and biancana evolution in southeast tuscany italy abstract biancane badlands consisting of small domes dissected by rills and micropipes with rough disordered microrehef can be found along the apennines in italy the dominant processes forming biancane differ from those of badlands formed on smectite rich mudrocks as micropipes associated with pseudokarstic enlargement of pores and cracks predominate and form the main routes for evacuation of eroded material biancana evolution is controlled by water infiltration into intact bedrock producing an erodible weathering rind which is more porous than intact rock this rind is easily removed by rill or micropipe flow and erosion is therefore weathering controlled depending on rind production by infiltrating water infiltration is initially slow and stepped due to slow water movement through very small capillary pores in intact rock alternating with rapid filling of macropores and cracks this occurs due to rapid matrix pore enlargement by dispersion and or dissolution the infiltration pattern is accurately reproduced by a model built on progressive development of weathering layers by moisture penetration model results are consistent with weathering rind depths and erosion observed in the field and show that a pipe network can be generated on newly exposed rock by the rainfall of one year propagation of the pipe network diverts a progressively larger proportion of runoff into micropipes expanding weathering rind production within the biancana as well as on the surface internal weathering and flow progressively dominate with few unweathered corestones and the biancana gradually collapses into a penultimate souffle like form

impact of physico chemical soil properties on erosion features in the aliano area southern italy abstract this study has been carried out on three pairs of clayey silt slopes which are examples of typical badlands near aliano southern italy these show features of erosion which are common to se exposed clayey silt rocks outcropping in the same area after mineralogical geochemical and grain size analyses these slopes were compared with the se exposed adjacent ones having however a different erosive action and a partially vegetated covering was found pedological analyses show a clear development of soil horizons where the slope is rich in organic matter and this is wholly consistent with the presence of vegetation a comparison between the eroded substrates and non eroded substrates showed that the former have higher 16 m the grain size also distinguishes crusts from substrates the latter having higher fractions tds ph sar and ps are parameters which distinguish the eroded from the non eroded sides of the slopes on average the eroded substrates have ph sar and ps values higher than the non eroded ones the esp values of the eroded slopes are slightly higher than those of the non eroded ones up to now the relations between ph tds sar ps and esp have been considered as descriptors of dispersivity however an improvement can be made regarding the predictability of diagrams such as esp tds when taking mineralogical composition into consideration the crusts are less dispersive than the eroded substrates and the non eroded ones show the same feature as crusts this suggests that the most severely weathered part of a slope tends to reach a stable condition when a strong decrease in sar ps and esp occurs this study shows that the erosion mechanism involves morphological and geographic exposure climatic elements as well as grain size mineralogy chemistry and the exchange processes of soil

exploring the frequency size relationships of pipe collapses in different morphoclimatic regions abstract piping is an important land degradation process that occurs in almost all climatic zones this study analyses for the first time the frequency size distribution of different types of pipe collapses pcs sinkholes and compound depressions related to the coalescence of sinkholes compound sinkholes and elongated blind gullies exploring the frequency size relationships of pcs provides critical morphometric information about this hazardous erosion and ground stability process as well as its impact on hillslope denudation hillslope channel coupling and landscape development the analysis has been performed with field based inventories of pcs from five catchments located in two different morphoclimatic environments one in the semi arid ebro depression ne spain valpalmas catchment and four in the humid bieszczady mts se poland in total 724 pcs were mapped among which 335 pcs in valpalmas and 389 pcs in the bieszczady mts the morphometric analyses were based on the major axis the maximum length or width and area of the pcs despite differences between study areas from ne spain and se poland related to climate conditions rainfall regime soil water storage capacity spatial pattern of pipe networks vegetation cover and land use empirical cumulative frequency curves of pcs show similar patterns in all study sites indicating similar overall effects of piping erosion the size distribution of the inventoried pcs can be modelled satisfactorily with logarithmic functions with high goodness of fit values r2 0 93 for each type of pc and the combined set of pcs sinkholes and compound sinkholes blind gullies mapped in each area and in the five catchments together the pcs mapped in valpalmas are displaced towards larger dimensions attributable to local factors the applicability and limitations of frequency size relationships of pcs for geomorphological studies and hazard assessment are discussed

soil erodibility and processes of water erosion on hillslope abstract the importance of the inherent resistance of soil to erosional processes or soil erodibility is generally recognized in hillslope and fluvial geomorphology but the full implications of the dynamic soil properties that affect erodibility are seldom considered in canada a wide spectrum of soils and erosional processes has stimulated much research related to soil erodibility this paper aims to place this work in an international framework of research on water erosion processes and to identify critical emerging research questions it focuses particularly on experimental research on rill and interrill erosion using simulated rainfall and recently developed techniques that provide data at appropriate temporal and spatial scales essential for event based soil erosion prediction results show that many components of erosional response such as partitioning between rill and interrill or surface and subsurface processes threshold hydraulic conditions for rill incision rill network configuration and hillslope sediment delivery are strongly affected by spatially variable and temporally dynamic soil properties this agrees with other recent studies but contrasts markedly with long held concepts of soil credibility as an essentially constant property for any soil type properties that determine erodibility such as soil aggregation and shear strength are strongly affected by climatic factors such as rainfall distribution and frost action and show systematic seasonal variation they can also change significantly over much shorter time scales with subtle variations in soil water conditions organic composition microbiological activity age hardening and the structural effect of applied stresses property changes between and during rainstorms can dramatically affect the incidence and intensity of rill and interrill erosion and therefore both short and long term hillslope erosional response similar property changes linked to climatic conditions may also significantly influence the stability and resilience of plant species and vegetation systems full understanding of such changes is essential if current event based soil erosion models such as wepp and eurosem are to attain their full potential predictive precision the complexity of the interacting processes involved may however ultimately make stochastic modelling more effective than physically based modelling in predicting hillslope response to erodibility dynamics

pliocene quaternary transpressional evolution of the anzi calvello and northern s arcangelo basins basilicata southern apennines italy as a consequence of deep seated fault reactivation abstract in this paper we report the results of a study of the plio pleistocene anzi calvello basin and the northern sector of the s arcangelo basin southern apennines italy our work suggests that the evolution of the anzi calvello basin is related to the activity of a deep seated roughly nne trending dextral transpressional fault zone camastra transcurrent fault zone ctfz structural control of sedimentation by this structure is indicated by the geometry of the unconformity bounded stratigraphic units as well as by the deformation of the basin fill en echelon n s trending thrusts n to ne trending dextral transpressional faults and nw to nnw striking folds affecting the substratum constitute the surface response to lateral displacement along the ctfz the s arcangelo basin is bounded to the north by a deep seated roughly wnw nw trending sinistral transpressional structure valsinni lateral ramp vlr that terminates northwestward against the ctfz at the surface the vlr is dominated by back thrusts and by transpressional fault zones the vlr has been interpreted as the sinistral lateral ramp of the large scale valsinni thrust anticline and it is inferred to have strongly controlled local deposition within the s arcangelo basin the deep seated structures ctfz and vlr probably represent reactivated pre existing normal and transfer faults affecting the rigid apulian platform that were generated during passive margin evolution as well as during the flexural bending of the apulian lithosphere during the pliocene pleistocene these structures were reactivated as lateral ramps accommodating the thrusting within the apulian platform transpression along the lateral ramps in the apulian platform propagated upwards through the nappe pile giving rise to a complex surface structural pattern and the local development of flower like structures

biostratigraphy of the vendian cambrian sukharikha river section northwestern siberian platform the sukharikha river section contains more than 800 m of fossiliferous vendian and lower cambrian carbonate rock deposited in ramp shelf and slope environments a diverse fauna of small shelly fossils calcibionts brachiopods trilobites and archaeocyaths has allowed us to develop a multi taxa biostratigraphic framework for this section a dearth of distinctive fossils low in the sukharikha formation prevents us from determining the position of the vendian cambrian boundary abundant small shelly fossils and archaeocyaths in the uppermost sukharikha formation and low in the krasnoporog formation provide ample biostratigraphic control near the base of the tommotian stage but the nemakit daldynian tommotian boundary as defined at ulakhan sulugur on the aldan river is temporally ambiguous for this reason there is no precise definition of this boundary in the sukharikha river section we have provisionally placed the base of the tommotian stage at the first occurrence of nochoroicyathus sunnaginicus

geomorphic features of a badland biancane area central italy characterisation distribution and quantitative spatial analysis abstract the biancana landscapes rather common in several italian areas have a very complex morphology different geomorphic features often occur along the same hillslope from a morphological survey of an experimental site in southern tuscany the forms were classified and their distribution analysed spatial analysis of the biancane provided insights into the range of forces responsible for their formation and evolution the results confirm an evolutionary trend from an original gently sloping surface to a complex biancana landform emphasising a trend from the taller bean forms to the terminal souffle like and cone forms the presence of scarp and sliding forms in the most sloping areas and along the residual surfaces supports the hypothesis of a process influenced by base level acting initially by small mass movements spatial analysis did not reveal any systematic trend in the variability of the erosional features along the slopes variographic analysis showed that selected morphological attributes are spatially auto correlated over a short range suggesting that the erosive processes responsible for morphogenic evolution of biancane act mostly on a local scale the strong geometric anisotropy detected in directions parallel to the main jointing systems also indicated a broader scale tectonic control of biancane evolution probably in an early stage of their formation

carbon isotope stratigraphy and the problem of a pre tommotian stage in siberia carbon isotopic oscillations are useful to elucidate the stratigraphy and biogeochemical events around the precambrian cambrian transition new isotopic data from the manykaj and emyaksin formations of the eastern anabar uplift siberia help to correlate the lower cambrian and neoproterozoic cambrian transitional beds across the siberian platform the similarity of trends and amplitudes of the carbon isotopic curves together with biostratigraphic and sequence stratigraphic markers from the anabar uplift provide a precise correlation with the southern part of the siberian platform diagenesis of argillaceous limestones of the emyaksin formation has appar ently not affected the primary isotopic variations the resulting curve is nearly identical in sections about 100 km apart in the tommotian atdabanian portion of the formation relatively frequent and pronounced isotopic oscillations in the lower beds of the emyaksin formation fit between features i and ii of the southern siberian isotopic reference scale but are undetected therein owing to the deposi tional hiatus at the base of the tommotian stage in its type section this confirms the transgressive onlap from the north suggested by previous studies and makes the appearance of the cambrian skele tal fossils on the siberian platform less abrupt the hiatus in the south appears to embrace at least two biostratigraphic zones as recognized in the north the case is strengthened for a pre tommotian cambrian stage in siberia the biostratigraphic framework for which has been elaborated earlier

a study of rock alteration in the eye dashwa lakes pluton atikokan northwestern ontario canada abstract as a part of the research pertaining to evaluation of the suitability of crystalline rocks for the disposal of nuclear fuel waste a study of core samples from five boreholes in the eye dashwa lakes pluton reveals several types and degrees of alteration the different degrees of alteration are related to the intensity of pink coloration and the amounts of plagioclase and ferromagnesian minerals that are affected the alteration process has reconstituted plagioclase to pure albite in highly altered rocks whereas in unaltered and slightly altered rocks it occurs as oligoclase the alteration products chlorite and sericite are relatively fe rich in the highly altered rocks unaltered to slightly altered moderately altered and highly altered samples each occupy a distinct field in a cao mgo feo variation diagram a close association exists between alteration and fractures a model relating fractures alteration and fracture infillings is proposed distinct differences in chemical and some physical properties between altered and unaltered rocks indicate that significant changes have occurred the distinct physical and chemical characteristics of the alteration and its close association with faults and fractures suggest the need to consider alteration as an important parameter in evaluating crystalline rocks for nuclear fuel waste disposal

hydraulic conditions in experimental rill confluences and scour in erodible soils 1 few studies have examined processes active within rill networks or the effect of confluence geometry on rill sediment flux and it is not clear if observations from river confluences also apply at rill scale laboratory experiments were carried out in artificial rectangular rill channels with fixed and erodible beds to identify the effects of confluence geometry on hydraulic conditions and scour patterns symmetrical and asymmetrical confluences with angles from 19 to 90 were used hydraulic changes in the confluence zone in fixed bed experiments included decreased flow velocity increased shear velocity transition from supercritical to subcritical and from transitional to turbulent flow bed scour in the confluence zone resulted generally increasing with confluence angle but a more important influence was junction symmetry or asymmetry symmetrical confluences produced a symmetrical scour pattern mirroring the original channels but in asymmetrical confluences scour was more complex evolving to a symmetrical pattern with confluence angles higher than the original system results are consistent with channel evolution to an optimally branched system controlled by minimum power criteria but validation requires testing with more precise velocity measurement

tectonic forcing of evolution and holocene erosion rate of ravines in the marginal ganga plain india abstract understanding the processes of ravine formation and estimates of specific sediment yields ssy of these regions help in formulating mitigation policies significantly upto now in the ganga plain the work done on ravine formation erosion and ssy estimates has been speculative here utilizing i high resolution digital elevation models dems prepared from real time kinematic rtk survey and cartosat images of ravined zones and ii luminescence chronology we provide the first estimate of ssy from the ravines the results indicate that ssy in the marginal ganga plain mgp ravines may range between 600 100 t km 2 yr and 1600 200 t km 2 yr the correspondence between the orientations of fractures and that of first order ravine suggests that the ravine growth is genetically related to extensional stress regime of the peripheral forebulge further the clay sedimentology indicates that besides regional tectonics action of swelling clays may have accelerated development of the badlands the geomorphic relationship between the length of ravined catchments and incision in the trunk channels indicates that the river incision associated base level change is not playing an overarching role in the ravine formation in the mgp

soil pipe collapses in a loess pasture of goodwin creek watershed mississippi role of soil properties and past land use little is known about the association of soil pipe collapse features with soil properties or land use history three loess covered catchments in northern mississippi usa were characterized to investigate these relationships soil pipe collapses were characterized for their size type feature and spatial location along with soil properties across the three catchments although mapped as the same soil one of the catchments did not contain pipe collapse features while the other two had 29 4 and 15 4 pipe collapses per hectare these loess soils contained fragipan layers that are suspected of perching water thereby initiating the piping processes pipe collapses associated with subsurface flow paths were not always consistent with surface topography the surface layer tended to be non erodible while layers below even the upper fragipan layers were susceptible to erosion by pipeflow soil properties of the lowest fragipan layer were highly variable but tended to prevent further downward erosion of soil pipes and thus formed a lower boundary for gullies middle to lower landscape positions in one of the piped catchments contained anthropic soils that were highly erodible these anthropic soils were previously gullies that were filled in in the 1950s when forested areas assumed to have been established when land was previously converted from crop to forest land were converted to pasture three decades after this land use change from forest to pasture pipe collapses became evident in contrast the adjacent catchment that does not exhibit pipe collapse features experienced severe sheet and rill erosion prior to the 1930s while in cotton production the surface horizons above the lower fragipan layer were completely removed during this period thus the top soil layer that tends to form a bridge above soil pipes in the more erodible subsoil layers was removed this study showed that knowledge of soil characteristics or topography alone do not explain the distribution of soil pipe collapses as past land use can play a definitive role copyright 2015 john wiley sons ltd

quantitative study of piping processes in badland areas of the ebro basin ne spain abstract in the ebro basin piping is an ubiquitous erosion process in badland areas occurring in two main situations on slopes of exposed tertiary clays and in recently incised silty clay holocene valley fill sediments the quantitative importance of the main factors controlling piping processes in those conditions was obtained by statistical analysis based on multiple and stepwise regressions piping erosion is strongly related to a high sodium absorption ratio sar which favours clay dispersion however the statistical analysis indicates that the chemical characteristics and the physical chemical behaviour are a necessary condition but are not sufficient on their own to develop piping processes on the slopes piping is controlled by the physical and chemical properties of the material such as the dispersion index the granulometric fraction smaller than 4 m ph and crack density in the valley fill sediments piping is mainly controlled by the sulphate concentration in the water extract from saturated paste which is also associated with high sar values and the dispersion index in both geomorphic situations piping is always related to high crack density and high topographic gradient

investigation of relationships between measured field indicators and erosion processes on badland surfaces at petrer spain abstract indicators were obtained to measure and predict rill erosion and mass wasting in biancana and calanchi like badland areas rainfall simulation experiments were used to find a relationship between soil moisture change and sediment concentration behaviour this relationship appeared to be able to show in its role as indicator differences between materials affected by various degrees of rill erosion or mass wasting indicators explaining this relationship are surface characteristics runoff and infiltration characteristics and chemical and mineralogical soil properties from the experimental study it was concluded that the high infiltration capacity in materials affected by mass wasting resulted in an unstable soil and a high degree of erodibility the materials which were more affected by rill erosion or had a continuous crust at the surface were saturated earlier during the experiment than the other materials this saturation caused an increase in runoff the mechanism is explained as the system crossing a threshold after which flow hydraulics at the surface are more important for erosion processes than dynamic soil properties and infiltration characteristics

variations in soil dispersivity across a gully head displaying shallow sub surface pipes and the role of shallow pipes in rill initiation a small bifurcating gully head displaying shallow pipe development was surveyed to explore how far three dimensional patterns of geochemistry and sediment size can be related to hydraulic gradients in the local marl bedrock almeria se spain the crust sub crust and parent materials were sampled every 20 cm across a 2 m by 3 m grid and then analysed for dispersive and granulometric characteristics spatial patterns of sodium adsoption ratio sar for each layer were plotted separately in situ material at depths of 5 10 cm was only weakly dispersive and the thin 0 2 cm depth crust is also found to be mostly non dispersive paralleling ndings from other eld sites in almeria however the signature relating sar to electrical conductivity for each layer shows that in places the immediate sub crust layer 2 5 cm is highly dispersive the pattern is not random rather the sar of this sub crust layer follows inferred hydraulic gradients the dispersive hot spots being located in the most incised part of the small gully exacerbating the erodibility of that position patterns of sediment particle size and sorting do not correlate with inferred hydraulic gradients but surface material is slightly siltier than the sub crust clay fraction increased with depth and sar is shown to have a weak inverse relationship to particle size this association between sar and the increased clay fractions in the lower layers supports the inference that massive pipe enlargement in the messinian rich unit is suppressed by sub surface swelling since a reduction in in ltration capacity fc with depth can be inferred from these results in ltrating water must be de ected into the already vulnerable sub crust layer during rainfall events explaining the development of shallow pipe forms at preferential depths it is concluded that calcium replaces sodium in the crust during leaching leaving a calcic crust and a sub crust that is sodic and prone to subsequent pipe enlargement rill morphology in these materials also suggests that rills develop from these pipes when pipe roofs collapse i e rill discontinuity bridges steep headwalls and rills with excessively high depth to width ratios copyright 2004 john wiley sons ltd

structural evolution of the lucanian apennines southern italy abstract in this paper we present a study of an entire segment of the southern apennines of italy extending from the pollino mountain range to the south to the agri valley to the north in which all the units of the chain are represented combining regional information with detailed structural data obtained from the different tectonic units forming the orogenic belt the structure as well as the tectonic evolution of this portion of the orogenic belt are proposed the overall architecture of this segment of the southern apennines mountain chain represents the result of a complete orogenic cycle in which oceanic subduction syn collisional and post collisional events are well recorded structurally this segment of the orogenic belt exhibits two distinct structural levels separated by a major detachment surface the sole thrust of the accretionary wedge that occur at the surface in the allochthonous nappes and at depth in the adria continental margin the upper level is characterized by an imbricated fan system affecting the allochthonous terranes emplaced during oceanic subduction and the first stages of continent continent collision the lower level is represented by a duplex geometry that has developed in the post collisional stage during evolution of the foreland migrating thrust system involving the carbonate platform basin system of the adria block during the last stages of the mountain building process when the foreland thrust migration was locked by the thickening of the colliding continental crusts the southern apennines were thus affected by a severe strike slip tectonics that dissects the entire mountain belt deeply modifying the previous thrust geometry

fracture accommodated strain in the diamond joe stock arizona fractures filled with hydrothermal minerals form a dominantly radial pattern in the diamond joe stock these fractures record a portion of the deformation experienced by the pluton from the time that it was emplaced until it cooled to ambient conditions in individual outcrops fracture orientations are very consistant to within 10 where fractures cross k feldspar phenocrysts no shear offset is observed indicating that the fractures have opened by dilation we have measured the apertures of these veins and define a two dimensional deformation gradient matrix to characterize the uniaxial strain accommodated by each fracture we assume that each fracture represents one increment of strain and superimpose all increments in an individual outcrop to compute the fracture accommodated strain for that outcrop we calculate the orientation and magnitude of the principal strains for each outcrop as well as the area change accommodated by the fractures all of the outcrops have experienced a decrease in area that ranges from 5 a portion of this area change is interpreted as thermal contraction however in the central part of the pluton additional contraction is present in this portion of the pluton the amount of strain and area change correlates well with fracture abundance we interpret this additional contraction to result from volume changes associated with crystallization and or vapor exsolution during crystallization of the pluton

prediction of spatial patterns of collapsed pipes in loess derived soils in a temperate humid climate using logistic regression abstract soil piping tunnel erosion has been recognised as an important erosion process in collapsible loess derived soils of temperate humid climates which can cause collapse of the topsoil and formation of discontinuous gullies information about the spatial patterns of collapsed pipes and regional models describing these patterns is still limited therefore this study aims at better understanding the factors controlling the spatial distribution and predicting pipe collapse a dataset with parcels suffering from collapsed pipes n 560 and parcels without collapsed pipes was obtained through a regional survey in a 236 km study area in the flemish ardennes belgium logistic regression was applied to find the best model describing the relationship between the presence absence of a collapsed pipe and a set of independent explanatory variables i e slope gradient drainage area distance to thalweg curvature aspect soil type and lithology special attention was paid to the selection procedure of the grid cells without collapsed pipes apart from the first piping susceptibility map created by logistic regression modelling a second map was made based on topographical thresholds of slope gradient and upslope drainage area the logistic regression model allowed identification of the most important factors controlling pipe collapse pipes are much more likely to occur when a topographical threshold depending on both slope gradient and upslope area is exceeded in zones with a sufficient water supply due to topographical convergence and or the presence of a clay rich lithology on the other hand the use of slope area thresholds only results in reasonable predictions of piping susceptibility with minimum information

relationships between a new slope morphometric index and calanchi erosion in northern sicily italy the italian badlands or calanchi are common landforms in mediterranean areas including central and southern italy calanchi landforms may be compared to small hydrographic basins these landforms are characterised by dense hierarchical and rapidly evolving drainage systems carved into steep clayey slopes and by a sharply alternating pattern of furrows and narrow generally sharp crests this work presents a study of morphometric characteristics and a statistical analysis for two sites in northern sicily italy on outcrops of silty clay deposits affected by active erosion processes which give this area a typical calanchi landscape in particular factors closely linked to the characteristics of the hydrographic network and slope morphometry were considered and analysed the initial geometry of the slopes was reconstructed and statistically compared with that of the current calanchi slopes including the drainage network a new morphometric index morphometric slope index msi was defined to represent the initial slope geometry as a whole this index was found to be effective in defining the structure of hydrographic networks summarising the characteristics and type of slope evolution and quantifying the rate of soil erosion the rate was determined based on both linear gully erosion and areal landslides sheet and rill erosion morphogenetic processes and our analysis based on msi indicates the dominance of areal erosion msi could also be used for basins larger than calanchi to represent the characteristics of geomorphic processes

pleistocene strike slip tectonics in the lucanian apennine southern italy structural studies carried out in the lucanian apennines southern italy show that strike slip faulting was the principal mode of deformation of this area during middle upper pleistocene time w nw to e se trending left strike slip fault systems dissect the entire apennine mountain belt and affect the preexisting thrust geometry strike slip faults activated by a roughly e w shortening are characterized by different geometries representing the surface response to lateral motion occurring along deep seated structures the occurrence of different structural patterns which characterize different segments of strike slip system is related to 1 the depth of a major decoupling surface which separates the upper tectonic multilayered horizon apennines thrust belt system from the lower rigid horizon apulian belt in which strike slip structures have originated and 2 the geometric relationships between the strike slip faults and the thrust belt pattern which characterize the upper horizon the different segments of the strike slip system are interpreted as internal deformation developed within a crustal shear zone this zone which corresponds to the boundary between the apulian block and the apennine chain is characterized by sinistral movement as a response to the northwesterly convergent motion of the african plate with respect to europe

the role of some site geochemical processes in the development and stabilisation of three badland sites in almeria southern spain samples of both surface and subsurface soils were collected on various surfaces in three badland areas of differing ages tabernas vera and mocatan in almeria province southern spain data were explored with the aim of identifying any diagnostic geochemical relationships between site ec ph sediment size and sar which might constitute typical signatures for site materials with some success data for the three sites are further used to explore the hypothesis that changes in site geochemistry through time are involved in badland stabilisation it was found that 1 the physico chemical properties of the three sites can be differentiated by the functional relationship between ec and sar and this may represent a useful tool in characterising sites where piping predominates 2 there is some equivocal evidence that sediment size distribution may play an additional role in site diagnosis and evolution and 3 surfaces appear to lose sodium over time the suggestion being that sodium is either progressively buffered by calcium during leaching or exchanges with hydrogen on the cation exchange sites under a vegetation cover since other research suggests that smectite can also relocate down the profile on some marl sites reducing hydraulic conductivity and suppressing pipes we argue that the surface at tabernas may be capable of long term autostabilisation in which piping intensity progressively reduces however this possibility really applies only to fine grained densely structured materials and evidence from the silty triassic rich unit in the mocatan basin suggests that without a high clay content piping may be expected to increase through time from this standpoint contemporary badland morphology at mocatan does not represent an early stage of the forms seen in vera and tabernas

testing gis morphometric analysis of some sicilian badlands abstract calanchi badlands are erosion landforms characterized by areas with scarce or absent vegetation steep slopes knife edge divides and high erosion rates they are originated by a combination of morphogenetic processes partly similar to those shaping bigger fluvial landforms and therefore can be considered as field laboratories this paper presents the results of an investigation carried out in two badland sites located in sicily where the geometry of 25 calanchi has been characterized using digital elevation models having a mesh size equal to 2 m for each landform a power length volume relationship is established this relationship demonstrates that length of calanchi channels can be used as a reliable predictor of eroded volume as already verified for smaller linear erosion landforms such as rills ephemeral and permanent gullies moreover length volume width and depth of calanchi are combined into two dimensionless groups allowing to establish a morphological similarity between rills ephemeral permanent gullies and the studied badlands furthermore the hack s law which relates channel length to drainage basin area is applied to the 25 calanchi basins obtaining an exponent of this power law smaller than 0 5 this result indicates that basins do not become necessarily more elongate with increasing size finally the relationships between maximum length and width of the landforms are analyzed demonstrating that calanchi basins become wider and not longer and narrower when evolving and increasing their size

the recurring cycles of biancana badlands erosion vegetation and human impact abstract the biancana badlands a typical element of the southern tuscany landscape were in expansion for centuries until bulldozers began erasing them for land reclamation purposes over the last 10 15 years some of the scattered remnants of biancanas have been placed under protection in order to preserve their biodiversity and their particular cultural and geomorphological landscapes rural abandonment and the lack of appropriate management practices have contributed to vegetation encroaching on biancana badland slopes causing a loss of elements of high ecological and cultural values as well as eroded spots the aim of this paper is to explore the direction and rate of change in land use of the biancana badland landscapes over the last 50 years evaluating the erosion vegetation dynamics and examining the processes involved in two biancana badlands lucciola bella and crete di camposodo crete di leonina which are sites of community importance first we analysed the landscape changes that occurred in the biancana areas from 1954 to 2005 comparing old and recent land use maps twinspan classification was applied on selected plots of a plant dataset to distinguish vegetation types and identify the indicator species of each different type we then evaluated soil erodibility on the eroded biancana surfaces regosols and well developed vertisols which represent the coexisting extremes of the soil situation within the biancana badlands we empirically assessed the effects of a few roots on saturated soil shear strength to introduce direct links between plants and soil processes our results showed a decrease in bare or scarcely vegetated spots of 0 9 ha y 1 if the encroachment continues to progress at this rate in 35 40 years from now all the biancana domes will be completely re vegetated encroachment on the most eroded biancanas was mainly ascribed to generalist ruderal species such as avena fatua and dactylis glomerata we showed that rills and subsurface micropipes are characterized by the same erosion processes meaning that they can be contrasted and eventually halted by the same means and we observed a clear positive trend that will substantially suppress rilling at very low plant cover no more than 20 badlands were previously kept alive by limited but nonetheless devastating grazing activities if this picture is correct then mimicking traditional badland grazing practices seems to be a necessary step towards saving the landscape and biodiversity that the protected areas were established to preserve

long and short term evolution of several mediterranean denudation hot spots the role of rainfall variations and human impact abstract severe slope denudation is one of the most important environmental problems in the mediterranean region in particular badlands are widespread in central italy as a result of extensive clayey outcrops current climatic conditions and rapid quaternary uplift human activity may significantly affect the development and evolution of these denudation hot spots especially through changes in land use this work is focused on a badland site that has developed over the last 30 years on a gently sloping area of cropland in central italy the site named bargiano underwent cropland abandonment in 1980 and was selected to evaluate the effects of external forcing such as human impact and rainfall variations on the development of water erosion processes the remnants of the 1980 cropland surface and the present eroded surface were sampled using differential global positioning system techniques to perform a volumetric estimation of the eroded material and to calculate the average erosion rate for fairly large time spans the dgps survey was coupled with a 2 year monitoring with erosion pins in the region which permitted comparisons between long and short term average erosion rates in addition the analysis of the rainfall series recorded at the orvieto pluviometric station allowed us to assess and evaluate the role of critical rainfall events on denudation intensity finally a further comparison of the measured and estimated erosion rates from the bargiano site with the data recorded at other long lasting monitoring stations that are set up in certain key areas of central italy the tevere river and ombrone river basins revealed that the bargiano experimental hillslope experienced considerably higher erosion rates than were noted at the other sites our investigations demonstrated that cropland abandonment caused an increase in the erosion rate relative to what happened in natural areas characterized by similar physiographic conditions this finding is consistent with previously reported results for other badlands found in the mediterranean area moreover the results obtained suggest that after the abandonment of its cropland the bargiano site evolved in a cyclical manner that was driven by intrinsic thresholds to a greater extent than it was affected by external climatic changes

mapping badland areas using landsat tm etm satellite imagery and morphological data abstract soil erosion is the most influential component of land degradation for its strong impacts on both natural and agricultural environments in order to support effective intervention and recovery policies for eroded areas monitoring techniques should take into account the space time variability of the processes involved and make use of assessed mapping methodologies as baseline criteria for studying the dynamics of landform development when using multispectral data for mapping eroded areas low spectral separability is a significant limit in areas with complex features where soil materials are frequently remixed by surface runoff since multispectral satellite images are a valuable data source for multi temporal analyses of erosion processes at the medium scale we assessed how accurately a badland area can be identified from landsat tm and etm data a protocol for an optimal mapping was built up by testing the performance of different supervised algorithms and input layers spectral and morphological tests were carried out in a well known badland area of basilicata italy with an extension of 8000 ha results obtained from the use of spectral bands with and without thermal channel and principal components returned an overall accuracy ranging from 53 for classification on first three components to 72 for classification on all bands from tm with low values for the kappa coefficient 0 30 0 50 showing that the spectral information alone are insufficient to accurately identify badland areas in order to improve mapping we found that the integration of slopes and aspects derived from a digital elevation model dem can overcome problems inherent to the low separability of spectral signatures the use of morphological data was tested for different classification algorithms and integration approaches in discriminating badlands the better performing algorithm was mlc maximum likelihood classifier and the best results were obtained by integrating all seven bands including tir with slope and aspect maps as input within the classifier a 0 85 and k 0 75 for both the sensors we selected such parameters because they play an important role in characterising badlands of study area from a morphological perspective but the proposed approach is also conceptually simple and can be easily exported to other areas the obtained results support the hypothesis that the combined use of remote sensing imagery and auxiliary morphological data significantly improves the mapping of badlands over large areas with heterogeneous features thus providing a useful methodology for long term studies on soil erosion processes

soil loss rates due to piping erosion compared with surface soil erosion by water subsurface erosion piping is generally less studied and harder to quantify however wherever piping occurs it is often a significant or even the main sediment source in this study the significance of soil loss due to piping is demonstrated through an estimation of soil volume lost from pipes and pipe collapses n 560 in 137 parcels under pasture on loess derived soils in a temperate humid climate belgium assuming a period of 5 to 10 years for pipe collapse to occur mean soil loss rates of 2 3 and 4 6 t ha 1 yr 1 are obtained which are at least one order of magnitude higher than surface erosion rates 0 01 0 29 t ha 1 yr 1 by sheet and rill erosion under a similar land use the results obtained for the study area in the flemish ardennes correspond well to other measurements in temperate environments they are however considerably smaller than soil loss rates due to subsurface erosion in semi arid environments although local slope gradient and drainage area largely control the location of collapsed pipes in the study area these topographic parameters do not explain differences in eroded volumes by piping hence incorporation of subsurface erosion in erosion models is not straightforward copyright 2011 john wiley sons ltd

physical chemical and mineralogical properties of parent materials and their relationship with the morphology of badlands abstract badlands are present throughout the world but not everywhere do they have the same morphology the main objective of this study is to try to understand why these different morphologies occur by analysing the physical chemical and mineralogical characteristics of the parental material in which badlands have developed the study was carried out in three areas of the region of murcia south east spain abanilla mula and gebas several analyses were carried out i field analysis orientation slope length and shape of the slope presence and characteristics of the rills vegetation vegetation pedestals exposed roots stoniness physical and biological crusts saline efflorescence cracks popcorn piping processes sedimentation areas and mass movements ii physical chemical analysis of the soils colour texture aggregate stability bulk density organic matter ph electrical conductivity cations and cation exchange capacity total or equivalent calcium carbonate sodium absorption ratio and exchangeable sodium percentage and iii mineralogical analysis the results of the analyses reveal how the rounded shapes in the badlands that appear in abanilla have significant differences with respect to the angled shapes of mula and gebas which could explain the different morphologies in general abanilla has very small amount of sand higher bulk density small amount of organic matter lower cation exchange capacity and very high salinity as shown in the values of electrical conductivity sodio sar and esp on the other hand similarities were found between the badlands of the region of murcia with the calanchi angled shapes and biancane rounded shapes of italy

sulfur isotope geochemistry of fracture filling gypsum in an archean granite near atikokan ontario canada abstract gypsum occurs as fracture filling material in the eye dashwa lakes pluton near atikokan ontario sulfur isotope analyses and mode of occurrence indicate that the gypsum is probably of precambrian age even though associated calcite veins indicate a minimum age of 40 000 yr petrographic analysis suggests that the gypsum was formed by the interaction of porewater with epidote plagioclase and pyrite gypsum occurs in fractures at depths 500 m where it has remained in stable equilibrium since its formation the significance of its occurrence is examined with reference to implications for the disposal of nuclear fuel waste in crystalline rocks heat generated by nuclear fuel waste in a storage vault could cause dissolution of gypsum filling material and reopen the fractures however the impermeable nature of the gypsum filled fractures and their stable equilibrium at depths 500 m may provide a method of sealing open fractures

early fracture evolution within the eye dashwa lakes pluton atikokan ontario canada abstract the fracture history of part of the eye dashwa lakes pluton near atikokan ontario was investigated from drill core and surface fracture data the earliest fractures contain aplite and compose less than 5 of the population they developed during the initial stages of plutonic cooling and contraction in response to local magma related pressures internal pressures decreased as the pluton cooled subsequent fractures comprising more than 90 of the population formed soon afterwards under the influence of a regional subhorizontal nw se compression statistical analysis and field evidence indicate that subhorizontal and moderately dipping dip slip fractures are filled mainly with epidote these were followed by formation of steeply dipping to subvertical strike slip fractures that are filled mainly with chlorite the resulting fracture framework was well established by the end of the archaean minor stress changes since then have rejuvenated the old fracture zones rather than creating new zones

some physical and chemical properties of sediments exposed in a gully donga in northern kwazulu natal south africa and their relationship to the erodibility of the colluvial layers abstract gullies locally termed dongas are a characteristic feature of the landscape in central kwazulu natal and are highly associated with widespread stratified colluvial sediments and the buried palaeosols that have formed in this material research objectives were to find out which sediment property or properties contribute most to the vulnerability of the colluvium to gully erosion to study the erosion susceptibility of the sequence of buried stratigraphic layers and palaeosols and to improve understanding of the relationship between erosion susceptibility of the colluvial layers and palaeosols and their disposition in the landscape materials from several colluvial layers and palaeosols exposed in the donga sidewall of the dabekazi donga 13 km north of nqutu in central kwazulu natal were subjected to chemical and mineralogical analyses several dispersion and erodibility tests and were characterized physically exchangeable sodium percentages esp ranged from 0 to 23 and the dispersivity and erodibility tests revealed a range of dispersion potential and erodibility across the sequence of colluvial layers and palaeosols however a poor correlation was found between the results of different dispersion tests as well as between dispersion tests and dispersion related properties dispersion tests showed significant correlation with silt content an erodibility test using a flume showed very strong correlation with electrical conductivity ec and sodium adsorption ratio sar of the saturated paste extract and esp values the plasticity index ranged from 0 to 0 23 and estimated hydraulic conductivities ranged from 33 to 0 7 m day high correlation with esp and ec suggests that dispersion plays an important role in the erodibility of the materials under conditions of short duration turbulent water flow however colluvium in which deep gullying occurs is not necessarily strongly sodic also the degree of erodibility of the materials differs depending on the test used illustrating the complexity of the interactions that govern dispersion and erosion the erodibility of the colluvial layers and palaeosols from the dabekazi donga and properties with relevance to dispersion differ considerably down the profile indicating that geomorphic threshold conditions and position in the landscape with respect to surface runoff hydrology also codetermine donga erosion hydraulic conductivity estimates of the investigated materials are relatively high and do not differ sufficiently to enable lateral subsurface flow through and piping of these materials to be the main causes of donga formation

root tensile strength relationships and their slope stability implications of three shrub species in the northern apennines italy abstract the role of root strength is important in stabilising steep hillslopes which are seasonally affected by storm induced shallow landslides in the italian apennines steep 25 40 slopes underlain by mudstone are generally stable if they are covered by shrubs whose roots anchor into the soil mantle to quantify the mechanical reinforcement of roots to soil the root tensile breaking force and the root tensile strength of three autochthonous shrub species commonly growing on stiff clay soils of the northern italian apennines rosa canina l inula viscosa l and spartium junceum l were measured by means of field and laboratory tests for each test approximately 150 root specimens were used the tensile force increases with increasing root diameter following a second order polynomial regression curve the tensile strength decreases with increasing root diameter following a power law curve the field in situ tensile force required to break a root is always smaller than that obtained from laboratory tests for the same root diameter although their difference becomes negligible if the root diameter is smaller than 5 mm the influence of root tensile strength on soil shear strength was verified based on the infinite slope stability model the root reinforcement was calculated using the number and mean diameter of roots the factor of safety was calculated for three different soil thickness values 0 1 0 3 and 0 6 m and topographic slopes between 10 and 45 the factor of safety for the combination of 0 6 m soil thickness slopes smaller than 30 and vegetation of i viscosa l or s junceum l is always larger than 1 if a slope is steeper the factor of safety may be smaller than 1 for i viscosa l although it is still larger than 1 for s junceum l in the stiff clayey areas of the northern italian apennines i viscosa l mainly colonizes fan cone taluses and stabilises these zones up to a topographic gradient

large scale rainfall simulation to investigate infiltration processes in a small landslide under dry initial conditions the draix hillslope experiment few studies exist on infiltration processes in badlands although infiltration and subsurface lateral flows are known to contribute to soil erosion and to control slope instability our investigation was carried out in a 100 m plot located in a 0 5 ha landslide in black marls south east france an artificial sprinkling was performed with an intensity of 10 mm h 1 during 66 4 h interrupted with 8 4 h breaks kbr and kcl were used as tracers a pseudo steady state was reached after 25 35 h and 250 350 mm of rainfall the runoff coefficient was 40 ratio total runoff volume total sprinkling water amount pre event water pe contributed to the groundwater recharge at the very beginning of the experiment but pe contribution dropped steadily while the soil was saturating after around 200 mm of cumulative rainfall pe contribution started to rise steeply before reaching a nearly constant value this original mechanism implies an efficient transfer process of pe it was assumed from the description of the material structure and from hydrological evidences that pe was mainly drained from a structure porosity made of marl s flaked nature total pe contributions ranged from 25 to 79 pe contribution was over 50 in 2 3 of the observation wells over the recession phase release of pe occurred from the drainage of texture porosity the study showed that at the plot scale infiltration processes proved to be well organized despite the high heterogeneity and anisotropy of the material it was possible to propose a general conceptual model explaining the hydrological processes over time and area the peculiar structure of regolith originating from black marl is preserved over a large part of the weathering time so that the material structure type orientation of grains small large pores remains a first order control of water flow generation in black marl soils copyright 2012 john wiley sons ltd

quantitative analysis of tin and tungsten bearing sheeted vein systems several methods are investigated for the quantitative analysis of a range of sn w sheeted vein systems from southwest england and spain the methods are based on fractal concepts and include the measurement of vein thickness and spacing distributions and the development of a multifractal interval counting method equivalent to box counting in two dimensions the results indicate that sets of subparallel veins are generally distributed randomly or with only slight clustering and develop from fracture systems in which the spacing of veins is homogeneous the opening of the veins is much more heterogeneous suggesting localization of subsequent deformation and flow this is especially true in mineralized areas and together with power law distributions of vein thickness can be used to characterize mineralized systems new data presented in this paper suggest that fracture evolution may play a fundamental role in defining the location and style of sn w mineralization observed greisen dominated and disseminated sn w systems develop where the initial fracture system dominates the fluid flow regime whereas sheeted vein systems are best developed where stress induced critical behavior of flow in fracture networks controls the permeability and fluid flow of the system

the impact of the farming practice of remodelling hillslope topography on badland morphology and soil erosion processes abstract badland landforms created in plio pleistocene clay landscapes of the basilicata region of southern italy form marginal features in a semi arid landscape dominated by the widespread cultivation of subsidised cereals these badland features are high relative relief forms exhibiting a high drainage density and steep slopes with slope angles typically in excess of 35 economic incentives to increase agricultural productivity have resulted in the practice of remodelling these marginal areas using heavy earth moving equipment remodelling the badland features creates longer slopes at lower angles which can be cultivated using conventional farm machinery these changes in hillslope morphology have altered the degree to which soil erosion processes operating in these areas are spatially coupled in the badland areas erosion and deposition are strongly localised with minimal sediment delivery to ephemeral or perennial channel systems the economically driven change in land use from visually striking badland areas to newly remodelled fields for agricultural use results in an increase in the coupling of drainage networks and a net increase in soil erosion

process form relationships in southern italian badlands erosion rates and implications for landform evolution characteristic badlands are incised into plio pleistocene clays in basilicata southern italy creating steep scarp slopes with knife edge ridges calanchi and small dome shaped forms biancane erosion pin data for the period 1997 2003 give mean annual erosion rates for dome shaped biancane in the range 9 19 mm a 1 while rates for the calanchi scarps are lower at 7 10 mm a 1 the erosion pin data also show a non linear relationship with slope angle maximum erosion rates coincide with a slope angle of 35 within an envelope defined by combining the theoretical effects of both rainsplash and surface weathering monitoring of surface changes and erosion rates for two 0 5 m 2 cleared swathes on biancane forms reveals a complex relationship between weathering and erosion characteristic forms can develop from large blocks of intact clay bedrock over a time period of less than 30 a the implications of the measured erosion rates for the landform association of mountain front pediment domed inselberg are explored copyright 2005 john wiley sons ltd

badlands in marl lithologies a field guide to soil dispersion subsurface erosion and piping origin gullies abstract field scientists studying badland processes in mediterranean and semi arid climates require assurances that the material in which gullies are presented is not dispersive a dispersive context means first infiltration rates may be radically changing in very short periods due to swelling and deflocculation of clays second surface crusts could be the result of translocation of sodium into subsurface positions third rills may be formed or at least exacerbated by shallow subsurface erosion fourth large gullies with substantial up channel headcuts including so called bank gullies may have formed because subsurface pipes have collapsed and fifth that network connectivity and evolution may be principally internal being effected by subsurface pipe capture network integration and most importantly the bulk of the sediment moving around in the landscape is not being lost from the surface this paper presents a decision support tool to assist the effective diagnosis of a landscape s principal genetic process suite the soil s behaviour in response to its geochemistry in marls with high exchangeable sodium percentages esps is outlined in simple terms with minimum use of laboratory or field chemical investigations using examples the paper then presents a simple set of form indicators that can be used in the field to diagnose the possibility that subsurface process are dominating landscape erosion surface crust character ephemeral rills and large subsurface tunnel settings are explained and classified in a final section the geomorphological implications of piping in gullied landscapes are explored by reference to the literature on connectivity

control of climate and local topography on dynamic evolution of badland from southern italy calabria abstract this work deals with an integrated geomorphological and chemical physical study of calanchi landforms in site caulonia of se calabria southern italy developed on of late pliocene quaternary clay deposits the aim of this paper is to investigate how topography and rainfall quantity may affect runoff and slope processes in calanchi landforms by influencing the physical chemical and mineralogical properties of clayey sediments to this purpose a comparison has been made among the physical chemical and mineralogical features of calanchi materials sampled after a rainy period precipitation mean annual rainfall of 709 6 mm wet year with those sampled after relatively dry period mean annual rainfall of 431 4 mm dry year and in different topographic settings opposite flanks of a catchment exhibiting different steepness and lengths i e w to nw facing and e to ne facing slopes using a multivariate statistic approach which adopts the principal component analysis pca method to extract factors it has been possible to make a hypothesis of the main processes responsible for dynamic evolution of the study area the rainfall quantity coupled with topography has to be considered as the main control factor inducing changes in the physical chemical mineralogical parameters

the influence of groundwater on surface flow erosion processes during a rainstorm surface erosion rates on a disturbed natural soil in a 10 m indoor flume increased by an order of magnitude when a water table developed at a 10 cm depth during simulated rainstorms erosion rate increases did not correlate well with surface hydraulic flow conditions and all significant erosion increases began before the full soil depth was saturated before the water table reached the soil surface and before seepage was possible groundwater influenced erosion processes primarily by increasing unsaturated pore water pressures and decreasing soil shear strength in surface rainflow rather than through the direct entrainment of soil particles by seepage flow there was no unique morphologic expression of the influence of groundwater during a rainstorm subsurface processes influencing surface erosion were detected only by appropriate subsurface instrumentation which included micropiezometers tensiometers and time domain reflectometry erosion rate increases occurred all along the slope and were not concentrated at the base of slope due to a seepage zone soil depth was crucial to determining surface erosion increase it is likely that confusing trends in surface flow erosion rates in past studies have occurred due to unrecorded groundwater development or an emphasis on seepage effects groundwater must be monitored along hillslopes under all moisture and soil conditions in order to avoid misleading and inconsistent conclusions derived solely from surface flow or seepage data copyright 2002 john wiley sons ltd

piggyback basin development and thrust belt evolution structural and palaeostress analyses of plio quaternary basins in the southern apennines abstract in southern italy structural analysis of the intramontane pliocene quaternary terrigenous basins of sant arcangelo and ofanto shows that they are piggyback basins the recent uplift of the southern apennines provides good conditions for carrying out detailed studies of palaeostresses in relation to structure and sediment accumulation in such piggyback basins we demonstrate that in the pleistocene sant arcangelo marine basin a single n70 compression induced a complex pattern of folds and strike slip faults in contrast the older pliocene ofanto basin reveals a polyphase history characterized by successive tilts and palaeostresses according to different compressions in both basins compressional stresses are syn depositional the geometry of the sedimentary infill of these basins provides information on the thrusting activity in terms of location geometry and age we point out that in addition to sedimentary and structural studies including interpretation of seismic reflection data palaeostress analyses provide a valuable tool for deciphering development and evolution of compressional basins in a fold and thrust belt

how mudrock and soil physical properties influence badland formation at vallcebre pre pyrenees ne spain abstract soils regoliths and their parent materials were investigated in relation to the development of badlands in the pre pyrenees in ne spain on late cretaceous mudrocks under a mountain mediterranean climate whilst all the soils in the area which are developed on mudrocks show a good structure and support a dense plant cover the bare parent materials slake very rapidly giving rise to badlands characterized by high erosion rates several physical chemical mineralogical and micromorphological properties of soils regoliths and related parent materials were analyzed in order to explain their different susceptibility to erosion and to determine which of all these properties are better related to such erosive behaviour only micromorphological and porosity properties were able to explain the erosion susceptibility whilst mineralogical chemical and physico chemical specific surface area properties were not among the aggregate stability tests performed to estimate the relationships of soil components with the susceptibility to erosion the emerson test for macroaggregate evaluation was particularly well suited although no good correlation was found between the emerson test classes and organic matter content we observed that the degree of slaking in organic rich horizons was always lower than in subsurface horizons and regoliths consequently as far as organic rich aggregates are present in the soil surface the influence of water in producing slaking swelling and then erosion will be minimum however when regoliths and rocks are uncovered the influence of water in these particular materials through freeze drying and swell shrinking will give rise to mudrock desintegration leading to accelerated erosion

fractures and fracture infillings of the eye dashwa lakes pluton atikokan ontario fractures in the eye dashwa pluton near atikokan ontario can be subdivided on the basis of their filling materials these materials include aplite epidote chlorite and gypsum carbonate clay listed in order of decreasing age established from crosscutting relations textures indicate that infilling occurred during fracture growth continuous cooling of the pluton during fracturing is inferred from the expected crystallization temperatures of fillings fracturing began before the pluton was completely solidified 650 600 c and continued to temperatures below 100 c many fractures appear to have been sealed by the filling materials after initiation but were subsequently sheared and filled by lower temperature materials apparently the majority of fractures formed during or immediately after pluton solidification and new fractures became smaller and more restricted in location as cooling progressed fractures and filling materials are seen as important features in assessing the possibility of movement

soil erosion and hydrology of the western mediterranean badlands throughout rainfall simulation experiments a review abstract rainfall simulation experiments are widely used in geomorphological research in badland areas this technique contributed significantly to our understanding of badland geomorphology in the mediterranean belt due to the different types of simulated rainfall applied and the variable size of the plots a review of the state of the art is necessary this study confirmed that rainfall simulations are well suited to i analyse runoff infiltration processes and sediment detachment within badlands and ii to establish the factors determining the hydrological and erosion response at interrill scale in badland areas the hydrological response of badlands is characterized by rapid responses low to moderate infiltration rates ranging from close to 0 to 55 mm h 1 and high runoff coefficients i e 60 positive relationships are observed between antecedent soil moisture content and rainfall intensity on the one hand and runoff coefficients on the other sediment concentration and soil detachment rates are among the highest measured on the mediterranean region i e up to 84 8 g l 1 and 4722 4 g m 2 h 1 results show that rainfall intensity runoff coefficient and slope angle have a positive influence on sediment concentration and sediment detachment in the case of rock fragment cover its influence is variable according to the soil cover percentage rainfall simulations increase our understanding of the temporal and spatial variability of the soil erosion processes however rainfall simulation provides mostly qualitative rather than quantitative information because of the small plot size and the simulated rainfall characteristics due to facility for repeating experiments and recording a high quantity of data in short time however this method allows the comparison amongst different environments and soil conditions as the rainfall properties can be reproduced

the influence of physico chemical material properties on erosion processes in the badlands of basilicata southern italy piping tunnelling appears to be one of the more significant methods of erosion in the badlands in the plio pleistocene marine sourced clays of the basilicata area in southern italy a detailed field investigation of the pedological textural mineralogical and geochemical properties of the clay rich terrains widely outcropping in two selected badland field sites the fossa bradanica area and the bacino di sant arcangelo was undertaken to further elucidate process variability across the complex site paralleling findings from other piped badlands certain physico chemical properties of the clays were found to influence the different erosional processes in fundamental ways the very dispersive nature of the materials enhances pipe enlargement so that subsurface flow rapidly becomes the dominant process causing pipe enlargement by a process of positive feedback the paper speculates on the progressive role of surface and subsurface processes in the genesis of all evolutional badland forms calanchi calanchi mammellonari and biancane in an early stage the calanchi mammellonari are produced as slope mounds become increasingly separated by a dense network of small inclined pipes in the intermediate part of the slopes a site which is presumed to favour elevated subsurface flow when the overburden collapses many cones are isolated in these portions of the slope a second stage follows in which overland flow dominates with the water canalizing into small gullies generated by the collapsed crust at the base of many slopes this same mechanism produces biancane as residual cones because of the structural weakness of piped materials mass movements cannot be ruled out in a few locations landsliding may be involved especially in the formation of calanchi mammellonari in this case the intersection of the vertical pipes with the impermeable substratum focuses subsurface flow and collapse of the surface along this failure plane subsequent remodelling occurs by surface processes since the catchment volume for large pipes no longer exists this interpretation differs from that of others who have argued that in other locations the biancane formation is linked to the development of large vertical pipes along tectonic joints

preliminary study of the erosion mechanisms in a biancana badland tuscany italy abstract italian badlands are present along the appennini mountains with an annual precipitation which ranges from 400 to 1200 mm the genesis of these badlands has often been studied whereas current processes and erosion rates have only rarely been examined and measured this paper describes a preliminary study on a badland developed in temperate mediterranean climate and located in sw tuscany italy the selected site is characterized by biancane dome shaped features a few meters in height generally having a vegetated nne aspect and severely eroded ssw slope with a sub horizontal basal pediment field rainfall and runoff experiments were carried out field results were substantiated by data collected in specially devised laboratory tests it was concluded that near surface pipes which develop at the point of contact between a surficial layer of weathered and severely fractured regolith and the less fractured and weathered regolith underneath are the main drainage channels while rills play a secondary role soil detachment is largely due to mechanical and chemical slaking of the regolith during infiltration the role of runoff is almost solely transport in particular it was found that the runoff detachment rate is limited by the rate at which the water front penetrates into the regolith

mineralogical and grain size composition of clays developing calanchi and biancane erosional landforms abstract clayey terrains outcropping in many parts of italy are frequently affected by accelerated erosion processes producing landforms known as calanchi and biancane the calanchi are intensely dissected landscapes presenting rill and gully landforms and a dense dendritic drainage network the biancane are landforms characterized by bare cones and hummocks separated by flatter areas of surface wash deposits the factors controlling the development of these two landforms are still poorly understood this study was undertaken to identify the material properties of calanchi and biancane the data suggest a biancane tend to develop in very fine sediments such as silty clays with a very high clay content 65 70 b calanchi tend to occur in relatively coarser sediments such as clayey silts and sandy clayey silts having a notable sand fraction 6 18 c both biancane and calanchi may develop in intermediate textures such as silty clays and clayey silts made up of approximately equal quantities of silt and clay d no strong trend in clay mineralogy can be correlated with the landforms the swelling phyllosilicate contents are roughly equivalent in the parent materials of biancane and calanchi e pore water chemistry seems to play a very important role in the development of these landforms the biancane have high concentrations of sodium relative to other cations essentially calcium and magnesium in pore water all the analysed calanchi pore waters have low concentrations of sodium relative to divalent cations

connectivity as a crucial determinant of badland morphology and evolution the way in which threshold behaviour landscape sensitivity and connectivity1 operate together at the meso and macro scale in badlands is initially considered from a theoretical energy utilisation perspective the argument is developed that intrinsic changes to process domain dominance can result in progressive shifts in process connectivity without the need to invoke external climatic or tectonic change from this premise a meso scale closed system model for the evolution of connected states in regionally isolated badlands is developed applicable to systems evolving towards a fixed base level within a less erosive host landscape the model shows how badlands disconnected from regional drainage can develop from a wide range of initial states into a convergent quasi equilibrium followed by a period of complex response as energy is dissipated across thresholds giving rise to a range of equifinal maximum entropy landscapes this classification is illustrated using a range of global badland examples longer term macro scale interruptions to this semi deterministic model of badland relief degradation are also considered from this longer term larger scale perspective it is argued that extrinsic changes to relative relief can be driven by base level changes tectonically isostatically or eustatically induced in which case the continuity and linkages of information within the system are modified by effects which move up through the system bottom up control macro scale climatic changes also alter connectivity by changing the power distribution of prevailing events and by causing long term changes in mean precipitation temperature and e p ratio which affect vegetation and therefore runoff resistance all across the landscape from this perspective longer term climatic change operates in a top down manner the interplay between these two larger scale controls will inevitably determine the pattern of connected states that the landscape experiences through time the top down and bottom up combinations that can lead to either rejuvenation and a return to the stages described for the closed system model or stabilisation enhanced phases of both morphological and geochemical stabilisation are discussed

geomorphological chemical and physical study of calanchi landforms in nw sicily southern italy abstract this work deals with an integrated geomorphological and chemical physical study of calanchi landforms in two sites ottosalme and catalfimo of nw sicily southern italy developed on dominant silty clay deposits the calanchi fronts are characterized by different morphological features and dominant geomorphic processes sharp knife edged ridges and concentrated water runoff dominate at ottosalme and smoother landforms affected by mass movements mud flows and translational slides prevail at catalfimo we focused on some geochemical and physical parameters such as ph total dissolved salts sodium adsorption ratio sar porosity plastic and liquid limits as possible causes of the above differences with special emphasis on their role in discriminating the behavior of peculiar microforms such as a weathered outer crust and the corresponding inner massive portion unweathered substrate our results show that the main chemical physical features of calanchi morphologies and microforms often display no clear correlations with respect to those reported in the existing literature pointing to a higher complexity of patterns and behaviors in particular all samples consist of dispersive material sar values 10 but a more plastic and liquid behavior at catalfimo can explain a higher occurrence of landslides and smoother morphology than at ottosalme higher sar values at ottosalme well explain the dominance of concentrated water erosion the chemical behavior of the studied microforms is better described by ph being alkaline with higher values in the inner substrate than the outer crust and appears to minimize the effects of all other parameters and their responses to other external controlling factors lower sar values in the crust suggest that clay dispersivity is not the prominent factor controlling its surface detachment and mobility downslope which is more likely promoted by its higher porosity and consequent water absorption than the inner portion with changes in the saturation state shear strength and water pressure

origin of biancane and calanchi in east aliano southern italy abstract areas underlain by plio pleistocene marine mudstone in south italy are severely affected by denudation processes and have been transformed into badlands with two well defined types of landform biancane and calanchi in this paper factors that contributed to the development of the aliano badlands and particularly to the geneses of biancane and calanchi have been studied based on aerospace data field observations on geomorphic processes and geological structure laboratory measurements of soil and bedrock samples and morphometric analysis several maps and spatial data were prepared to describe factors which are thought to be related with landform formations such as lineament distribution elevation slope and pipe distribution morphometric characteristics of biancane and calanchi steepness and slope length dominant active processes and the dip orientation of beddings joints and fault planes were investigated and 71 samples of soils and bedrock were taken to characterise their properties the results of the analyses of the soil bedrock samples show no significant differences in their properties between biancane and calanchi field observations do not support the idea that biancane are the final product of calanchi development but support the hypothesis that biancane and calanchi are formed under different terrain conditions related to structural patterns and denudation processes of highly erodible materials the origin of biancane is associated with highly dissected surfaces along a reticular system of small joints in contrast calanchi are formed on steep wall like slopes along larger lineaments where the rate of incision into the slopes surpasses the denudation of the densely vegetated back slope

alpine gullies system evolution erosion drivers and control factors two examples from the western italian alps abstract denudation processes affecting mountain slopes may vary according to different factors e g lithology and structural setting of bedrock climate relief features which may be very diverse at the local scale gully complex systems characterised by morphological features similar to those developing in other climate contexts i e pseudo badlands are also becoming common at higher altitudes and latitudes the selected study cases of gran gorgia susa valley and saint nicolas aosta valley in the western italian alps are sites of geomorphological interest as they are specifically relevant for their scientific features the aims of this work are i reconstructing the morphometric evolution of gully systems and vegetation colonisation time by means of multitemporal spatial analysis on surface morphological changes under water erosion ii reconstructing in detail through dendrogeomorphological analysis the progressive spatial surface denudation and changes in erosion rates by analysing trees and exposed roots and using different indicators i e compression wood traumatic resin ducts iii obtaining data on successive aggradation degradation episodes along slopes surrounding such hotspots through geopedological investigations and iv identifying which control factors exert a predominant role on denudation patterns in such contexts multidisciplinary analyses regarding the study sites allowed for detailing of erosional history of the studied slopes detecting the prevailing drivers of their evolution according to the results and considering the common climate and bedrock conditions the structural background seems to have more influence on slope evolution at the saint nicolas site while superficial geomorphic processes seem to be more relevant at the gran gorgia site because the sites have already been recognised as part of geoheritage by local authorities the data obtained in the present research on their genesis evolution and local drivers affecting the rates of denudation i e scientific relevance of the site suggests that description of the sites for dissemination purposes should include links to the entire slope history

badlands denudation hot spots the role of parent material properties on geomorphic processes in 20 years monitored sites of southern tuscany italy abstract some monitoring stations have been recording for 20 years the geomorphic processes acting on calanchi and biancane badlands located in the tyrrhenian side of central italy field monitoring was aimed at studying the dynamics of surface processes such as sheet rill and gully erosion shallow landsliding piping and tunneling considering their space time variability as a consequence of both natural factors and human pressure this paper shows the results of grain size geochemical and mineralogical composition of parent materials from upper orcia valley sites southern tuscany to further elucidate the role of their properties on processes acting on both bare and vegetated surfaces parent materials properties are discussed with respect to the initiation and development of different badlands processes in particular clay dispersivity at different depths in the sample sites is examined as a well known controlling factor of accelerated erosion thus providing some interesting clues for understanding the spatial variability of denudation rates in the considered badlands sites

a new empirical model for estimating calanchi erosion in sicily italy abstract calanchi plural of calanco are typical badland landforms of the italian landscape they consist of dense networks of v shaped valleys with a sparse or absent vegetation cover which frequently develop on unconsolidated or poorly consolidated clayey deposits in this paper the dimensional analysis and the incomplete self similarity theory were used to deduce a model relating the volume of sediments eroded from the calanchi area to a set of geometric attributes of their tributary areas the morphometric characteristics of 209 calanchi basins were used to calibrate and validate the model the predictive skill of the model was assessed by calculating the mean square error and the nash sutcliffe model efficiency coefficient the model was found to provide a reliable prediction of eroded volume from basins entirely covered by calanchi landforms as well as from basins only partially affected by badland erosion processes furthermore as the residuals between the calculated and the measured volume of the eroded material are normally distributed the deterministic model may be considered complete meaning that no other variables are necessary to explain the studied physical process in other words the model is able to predict erosion volume in calanchi landforms from a deterministic point of view

erosion processes in calanchi in the upper orcia valley southern tuscany italy based on multitemporal high resolution terrestrial lidar and uav surveys a 125 000 m2 calanchi badland in the province of siena tuscany was monitored with an unmanned aerial vehicle uav and terrestrial laser scanning over the period of one year tls terrestrial laser scanning was carried out on two sample slopes whereas the image acquisition of the uav covered the entire catchment in combination with ground control points the uav images were used to create orthophotos and 3d point clouds using the structure from motion sfm software photoscan the tls surface models indicate seasonal differences in erosion and deposition the surface change measured with sfm showed nearly 6 700 m3 of net material loss resulting from 8 700 m3 erosion and 2 000 m3 deposition these values reveal a mean annual surface lowering of 5 3 cm for the catchment additionally several geomorphological processes such as rill erosion slope wash and translational slides could be detected in the one year monitoring period a comparison of tls and sfm results showed differences in the calculated volumes of mobilised material these discrepancies resulted from shadowing effects and low point densities of the tls point clouds