deep seated gravitational slope deformations related landslides and tectonics abstract deep seated gravitational slope deformations and their relationships with tectonic deformation of rocks is considered to examine the viewpoint of tectonics as a causative factor in slope deformation first a distinction is made between the different types of deep seated gravitational slope deformation then the geomorphological and structural effects of the different macrostructural deformations induced by tectonics on the scale of the whole deforming ridge is briefly discussed finally some case studies that represent either verified or possible cases of gravity deformation in response to tectonic activity are used as illustration

genesis of autochthonous and allochthonous apulian karst bauxites southern italy climate constraints abstract the apulian carbonate platform acp in southern italy has experienced several episodes of subaerial exposure which were in some cases associated with the formation of karst bauxite deposits the acp contains both autochthonous canyon like bauxite and allochthonous salento type bauxite with the latter having been derived from a weathered and eroded pristine bauxite deposit the remnants of this pristine bauxite are preserved as transported pebbles embedded in a clayey matrix the autochthonous bauxite and the pebbles of the allochthonous bauxite have the same texture of sub spheroidal components ooids dispersed in a fine grained matrix the fractal dimension of ooids from both deposits is very similar and corresponds to the growth of aggregates under a diffusion controlled process the ooids of the autochthonous bauxite have a different composition to those in the pebbles of the allochthonous bauxite because they formed under different climatic conditions during the turonian autochthonous bauxite ooids formed in alternating wet tropical conditions promoting al hematite formation and drier conditions favouring boehmite stability in the allochthonous pebbles ooids formed mainly in a dry climate promoting the formation of large boehmite cores the ooids matrix ratio and the geometrical features of the ooids reflect these climate differences the differences in composition and age post turonian of the salento type bauxite bedrock suggest that the pristine bauxite that produced the salento type pebbles was different in composition to and younger in age than the canyon like bauxite the latter probably formed during a middle campanian emersion event evidenced by large karstic cavities which is correlated with the subaerial exposure of karst recorded on the adriatic island of brac

effective electrode array in mapping karst hazards in electrical resistivity tomography when conducting environmental and engineering investigations in karst terranes engineers and geologists often supplement exploratory borehole results with data gathered from surface geophysics to reduce the site characterization cost and establish the most useful locations for borings or samples when conducting resistivity investigations a frequently occurring problem is the need to determine which of the many existing electrode configurations will respond best to the material changes in karst features each array has its advantages and disadvantages in terms of depth of investigation sensitivity to horizontal or vertical variations and signal strength in the application presented in this paper numerical forward modeling was conducted of dipole dipole schlumberger and wenner arrays and they produced markedly different anomaly shapes for a conceptual model of the development of a cover collapse sinkhole the resolution of the three above mentioned arrays was further evaluated along a section of i 70 near frederick maryland where a sinkhole had occurred in the median of the highway the image from the dipole dipole array appeared to be better than those from the wenner and schlumerger arrays in displaying the sinkhole collapse area however they are all less effective than a mixed array in which apparent resistivities from all the three arrays are combined and processed together in the model because the mixed array requires a significant increase in data collection the dipole dipole array appears to be the most effective and less costly configuration in mapping karst hazards areas this conclusion was then confirmed by two case studies

distribution of clay minerals along a weathered pyroclastic profile hong kong abstract the distribution of clay minerals along a weathered profile developed over crystal vitric tuffs are examined by x ray diffractometry xrd and scanning electron microscopy sem techniques chlorite and illite are the most abundant clay minerals in fresh and moderately decomposed rocks respectively chlorite is limited to fresh samples whereas illite and trace amounts of interstratified illite smectite are ubiquitous along the profile halloysite and kaolinite are the dominant clay minerals in highly to completely decomposed rocks halloysite clusters in moderately decomposed samples provide clear evidence of crystallization from solution whereas vermiform kaolinite books reveal evidence of transformation from illite in most samples in general as the intensity of weathering increases a kaolin to illite and kaolinite to halloysite ratios increase and b the morphology of halloysite varies from spheriodal clusters to tubular aggregates it is concluded that the nature type and abundance of clay minerals along the profile result from complex combinations of several different processes controlled mainly by three factors the pre weathering alteration history of parent rock the degree of weathering and microenvironmental conditions the relative role of each factor can vary significantly within the same profile as evidenced by mineralogical and petrographical characteristics the nature and type of clay minerals in fresh and moderately decomposed rocks can be attributed to pre weathering hydrothermal and or deuteric alterations on the other hand the degree of weathering regulates the nature type and abundance of clay minerals particularly kaolin group minerals in highly to completely decomposed rocks sesquioxides are sensitive to microenvironmetal conditions and can modify the distribution of clay minerals regardless of the degree of weathering of the rock

onset and timing of deep seated gravitational slope deformations in the eastern alps italy abstract a previously unrecognised complex of deep seated gravitational slope deformations dsgsd extends 20 km along upper venosta valley in the eastern alps italy mt watles exhibits spectacular features indicative of dsgsds including double ridges trenches and counterscarps the slope deformation occurs along a nappe boundary now corresponding to the schlinig normal fault is also conditioned by recent faults marked by shallow earthquakes and shows glacial paraglacial controls on slope evolution the mt watles dsgsd is a complex deep seated compound slide along a basal shear zone involving the schlinig fault gravitational reactivation of ne trending fractures formed gravitational scarps counterscarps and half grabens in the upper slope whereas the lower part of the slope partially collapsed although our work indicates the importance of the schlinig fault and recent fracturing on slope failure the trigger seems to be postglacial debuttressing of the valley walls radiocarbon dating of peat deposits within one of the major counterscarps indicates that slope deformation started during the lateglacial period and continued during the holocene in several slope sectors

tectonic controls on a large landslide complex williams fork mountains near dillon colorado abstract an extensive 25 km2 landslide complex covers a large area on the west side of the williams fork mountains in central colorado the complex is deeply weathered and incised and in most places geomorphic evidence of sliding breakaways hummocky topography transverse ridges and lobate distal zones are no longer visible indicating that the main mass of the slide has long been inactive however localized holocene reactivation of the landslide deposits is common above the timberline at about 3300 m and locally at lower elevations clasts within the complex as long as several tens of meters are entirely of crystalline basement proterozoic gneiss and granitic rocks from the hanging wall of the laramide late cretaceous to early tertiary west directed williams range thrust which forms the western structural boundary of the colorado front range late cretaceous shale and sandstone compose most footwall rocks the crystalline hanging wall rocks are pervasively fractured or shattered and alteration to clay minerals is locally well developed sackung structures trenches or small scale grabens and upslope facing scarps are common near the rounded crest of the range suggesting gravitational spreading of the fractured rocks and oversteepening of the mountain flanks late tertiary and quaternary incision of the blue river valley just west of the williams fork mountains contributed to the oversteepening major landslide movement is suspected during periods of deglaciation when abundant meltwater increased pore water pressure in bedrock fractures a fault flexure model for the development of the widespread fracturing and weakening of the proterozoic basement proposes that the surface of the williams range thrust contains a concave downward flexure the axis of which coincides approximately with the contact in the footwall between proterozoic basement and mostly cretaceous rocks movement of brittle hanging wall rocks through the flexure during laramide deformation pervasively fractured the hanging wall rocks

chemical processes affecting the mobility of major minor and trace elements during weathering of granitic rocks abstract the behaviour of 38 major and trace elements as well as changes in the mineralogy have been examined in 10 weathering profiles developing on some portuguese granitic rocks element mobilities are calculated from geochemical data normalized with respect to ti in the fresh parent rock chemical elements are divided into two groups immobile and mobile on the basis of their geochemical distribution during weathering elements that are immobile during weathering are zr hf fe al th nb sc and the ree very mobile are ca na p k sr ba rb mg and si mobile elements are derived mainly from leachable minerals such as feldspars micas and apatites whereas immobile elements are either concentrated in resistate phases or strongly adsorbed by secondary minerals the geochemical behaviour of mn cr v fe and ce is very dependent on redox conditions redox transformations of these elements can be used to set limits on the oxidation state of a weathering suite the ree are mobilized or fractionated during late stages of weathering but not during moderate stages of weathering this fractionation is caused by selective leaching of rocks composed of both stable and unstable minerals containing ree

lateritization and bauxitization events laterites and bauxites are produced in tropical soils by weathering which enriches iron of laterites and alu mina of bauxites as well as trace elements such as nickel gold phosphorus and niobium to ore grade la terites and bauxites can be redeposited into sedimentary sequences and remain as ores if not transported far and diluted with other materials the age of redeposited laterites and bauxites and of bauxitic and lateritic pa leosols can be established from the geologic age of overlying rocks an approach especially effective in pale osols within sequences of isotopically datable volcanic rocks lateritic profiles can also be dated by paleomag netic inclination in special cases in which land masses such as in australia and india drifted long distances northward during cenozoic time in addition cryptomelane and other k mn oxides can be dated by k ar and 40ar 39ar techniques to obtain multiple ages from different crystals in a single relict paleosol compilation of new and more accurate laterite and bauxite ages reveals unusually widespread and intense laterite and bauxite formation during events of less than 100 k y duration at 2 12 16 35 48 55 65 and 100 ma such events can also be inferred at times older than 100 ma from paleolatitudinal distribution of laterites and bauxites but these are poorly sampled laterite and bauxite peaks were coeval with times of global high warmth and pre cipitation elevated atmospheric carbon dioxide oceanic anoxia exceptional fossil preservation and mass ex tinction these co2 greenhouse events and attendant titration of carbonic acid with soils are interpreted as transient fluctuations in the atmosphere produced by meteorite impact flood basalt volcanism and methane outbursts concentration of bauxite and laterite resources in particular stratigraphic horizons formed during greenhouse crises suggests the usefulness of an event stratigraphic approach to exploration and exploitation of these and related ores

application of field geophysics in geomorphology advances and limitations exemplified by case studies abstract during the last decade the use of geophysical techniques has become popular in many geomorphological studies however the correct handling of geophysical instruments and the subsequent processing of the data they yield are difficult tasks furthermore the description and interpretation of geomorphological settings to which they apply can significantly influence the data gathering and subsequent modelling procedure e g achieving a maximum depth of 30 m requires a certain profile length and geophone spacing or a particular frequency of antenna for more than three decades geophysical techniques have been successfully applied for example in permafrost studies however in many cases complex or more heterogeneous subsurface structures could not be adequately interpreted due to limited computer facilities and time consuming calculations as a result of recent technical improvements geophysical techniques have been applied to a wider spectrum of geomorphological and geological settings this paper aims to present some examples of geomorphological studies that demonstrate the powerful integration of geophysical techniques and highlight some of the limitations of these techniques a focus has been given to the three most frequently used techniques in geomorphology to date namely ground penetrating radar seismic refraction and dc resistivity promising applications are reported for a broad range of landforms and environments such as talus slopes block fields landslides complex valley fill deposits karst and loess covered landforms a qualitative assessment highlights suitable landforms and environments the techniques can help to answer yet unsolved questions in geomorphological research regarding for example sediment thickness and internal structures however based on case studies it can be shown that the use of a single geophysical technique or a single interpretation tool is not recommended for many geomorphological surface and subsurface conditions as this may lead to significant errors in interpretation because of changing physical properties of the subsurface material e g sediment water content in many cases only a combination of two or sometimes even three geophysical methods gives sufficient insight to avoid serious misinterpretation a good practice guide has been framed that provides recommendations to enable the successful application of three important geophysical methods in geomorphology and to help users avoid making serious mistakes

vertebrate footprints from the kem kem beds morocco a novel ichnological approach to faunal reconstruction the first survey of vertebrate fossil tracks and trackways from the well known kem kem beds of southern morocco is here presented the aims are to 1 discuss the diversity of vertebrate trackmakers represented in two trace yielding units at three localities and 2 apply the novel data to ongoing debates about vertebrate ecological associations within the kem kem the majority of the tracks we recorded from the kem kem are tridactyl theropod footprints other dinosaurian track records include those of possible ornithopod dinosaurs extremely rare as body fossils within kem kem collections traces of swimming turtles are reported alongside the first tracks of crocodyliforms and possible pterosaurs to be recorded from the moroccan cretaceous both unsurprising given their abundance as body fossil records in this region differences between the collected ichnological sample and faunal reconstructions made on the basis of skeletal evidence are discussed as trace fossils record the same environment in which the trackmaker lived i e not subject to post mortem transportation data of this type arguably provide a more precise palaeoecological sample than the heavily re worked and usually fragmentary body fossils from the kem kem

robust geochemical indices for redox and weathering on a granitic laterite landscape in central uganda abstract most geochemical studies of laterite formation have been based on detailed examinations of a small number of hopefully representative profiles due to spatial variability in bedrock composition and geomorphic processes that sort materials by size density and other properties experimental designs developed for the geochemical analysis of single soil profiles are of limited use in landscape investigations in this study of a laterite landscape on a granitic rock in uganda we used element concentrations from neutron activation analysis naa to develop a suite of robust geochemical indices for landscape scale analysis of weathering and oxidation reduction redox processes in laterite formation to capture k feldspar weathering the k hf ratio served as a good proxy for feldspar zircon mineral ratios while k na ratios indexed feldspar concentration to quartz using principal components analysis we derived an index of rare earth elements ree leaching relative to th and an index of heavy to light ree hree lree fractionation we used the fe sc ratio to ascertain the absolute redox vs relative weathering fe accumulation in laterite formation with absolute fe accumulation also associated with lower fe as ratios mn ce ba nodules and concretions were identified by characteristically high ce values with individual ce values as high as 5000 g g 1 the relatively large amounts of k feldspar k avg is 4000 g g 1 and low degree of hree lree fractionation suggest that this landscape is weathered less than generally assumed the fe and mn derived indices highlight the important role of oxidation reduction processes in iron accumulation overall our findings suggest that the current ferricrete mantled hilltops were formerly located on a lower poorly drained part of the landscape

a numerical comparison of 2d resistivity imaging with 10 electrode arrays numerical simulations are used to compare the resolution and efficiency of 2d resistivity imaging surveys for 10 electrode arrays the arrays analysed include polepole pp pole dipole pd half wenner hw wenner wn schlumberger sc dipole dipole dd wenner wb array gm multiple or moving gradient array gd and midpoint potential referred measurement mpr arrays five synthetic geological models simulating a buried channel a narrow conductive dike a narrow resistive dike dipping blocks and covered waste ponds were used to examine the surveying efficiency anomaly effects signal to noise ratios and the imaging capabilities of these arrays the responses to variations in the data density and noise sensitivities of these electrode configurations were also investigated using robust l1 norm inversion and smoothness constrained least squares l2 norm inversion for the five synthetic models the results show the following i gm and wn are less contaminated by noise than the other electrode arrays ii the relative anomaly effects for the different arrays vary with the geological models however the relatively high anomaly effects of pp gm and wb surveys do not always give a high resolution image pd dd and gd can yield better resolution images than gm pp wn and wb although they are more susceptible to noise contamination sc is also a strong candidate but is expected to give more edge effects iii the imaging quality of these arrays is relatively robust with respect to reductions in the data density of a multi electrode layout within the tested ranges iv the robust inversion generally gives better imaging results than the l2 norm inversion especially with noisy data except for the dipping block structure presented here v gd and mpr are well suited to multichannel surveying and gd may produce images that are comparable to those obtained with dd and pd accordingly the gd pd dd and sc arrays are strongly recommended for 2d resistivity imaging where the final choice will be determined by the expected geology the purpose of the survey and logistical considerations

global warming and the end permian extinction event proxy and modeling perspectives abstract the mass extinction event that occurred at the close of the permian period 252 million years ago represents the most severe biodiversity loss in the ocean of the phanerozoic the links between the global carbon cycle climate change and mass extinction are complex and involve a whole range of often inter related geochemical biological ecologic and climatic factors it has become widely accepted that the end permian mass extinction was associated with a global warming event because the age of the siberian trap eruption a potentially massive source of carbon dioxide coincides within error with the extinction event however geologic data that are in support of this global warming event are relatively sparse the chain of events and the causal relationship between the eruption of siberian traps and mass extinction is not well established global warming in particular has only been reported from limited proxy data and climate models for which the pco2 in the atmosphere just before and during the end permian extinction event is poorly known this study critically assesses both the proxy climate data and the existing paleoclimate simulations with the goals of assessing our current understanding of the link between mass extinction and climate change and providing some guidance for future studies proxies indicate that prior to the end permian extinction event tropical sea surface temperatures ranged from 22 to 25 c and possible pco2 values ranged from 500 to 4000 ppm before the extinction event during the peak extinction tropical temperatures rose up to 30 c while pco2 perhaps increased up to 8000 ppm climate models that use different pre event pco2 values show similar amount of co2 doubling to replicate the observed carbon isotope excursions we find that the temperature anomaly during the end permian extinction is consistent with 1 5 doublings of atmospheric pco2 and that the implied climate sensitivity is 5 6 c within the upper range of values produced by climate models

uphill facing antislope scarps in the coast mountains southwest british columbia uphill facing scarps are examined at affliction creek a glacierized area within the meager creek volcanic complex of southwest british columbia scarps occur directly downslope of tension cracks and are considered to have developed from a combination of 1 antithetic movement between partly toppled slices of rock defined by a master joint set dipping into the slope and 2 erosion of the upslope face of each tension crack leaving the downslope face prominent as an antislope scarp a kinematic test for toppling failure is described glacial erosion and rapid glacial downwasting are probable causes of toppling lichenometric data indicate significant scarp development since affliction glacier attained its maximum neoglacial dimensions about 140 yr ago dilatancy is cited as a possible mechanism for scarp stabilization

discovery of the ree minerals and its geological significance in the quyang bauxite deposit west guangxi china most of the karstic bauxite deposits in china are enriched in ree and the ree has commonly been considered to be adsorbed on the surface of clay or diaspore minerals as ion state however occurrence of ree minerals in the bauxite deposits has not been reported by far in the quyang bauxite deposit from guangxi province we find ree minerals the minerals are parisite and churchite parisite is widely distributed in the ooids and matrix inducing positive ce anomaly of the ores whereas churchite is rare and occurred in the core of ooid the compositions of the ree minerals show the eu anomaly can change gently during the weathering and the eu anomaly analyses suggest that the ree in the ores are mostly derived from the underlying carbonates the parisite is formed in an alkaline condition while churchite in an acidic situation the co existence of the two minerals in the ores suggests the permian environment for bauxite formation is complex with great change of ph value moreover parisite is inferred to be formed earlier than the churchite

object oriented identification of forested landslides with derivatives of single pulse lidar data in contrast to the many studies that use expert based analysis of lidar derivatives for landslide mapping in forested terrain only few studies have attempted to develop semi automatic methods for extracting landslides from lidar derivatives while all these studies are pixel based it has not yet been tested whether object oriented analysis ooa could be an alternative this study investigates the potential of ooa using only single pulse lidar derivatives such as slope gradient roughness and curvature to map landslides more specifically the focus is on both lidar data segmentation and classification of slow moving landslides in densely vegetated areas where spectral data do not allow accurate landslide identification a multistage procedure has been developed and tested in the flemish ardennes belgium the procedure consists of 1 image binarization and multiresolution segmentation 2 classification of landslide parts main scarps and landslide body segments and non landslide features i e earth banks and cropland fields with supervised support vector machines at the appropriate scale 3 delineation of landslide flanks 4 growing of a landslide body starting from its main scarp and 5 final cleaning of the inventory map the results obtained show that ooa using lidar derivatives allows recognition and characterization of profound morphologic properties of forested deep seated landslides on soil covered hillslopes because more than 90 of the main scarps and 70 of the landslide bodies of an expert based inventory were accurately identified with ooa for mountainous areas with bedrock on the other hand creation of a transferable model is expected to be more difficult

the late permian climate what can be inferred from climate modelling concerning pangea scenarios and hercynian range altitude abstract a major unsolved geodynamic problem is the permian pangea plate configuration at the end of paleozoic era around 255 ma while consensual geology indicates a plate arrangement close to that of the jurassic prior to the atlantic opening pangea a paleomagnetic data indicates a nearly 3000 km more eastward position of gondwana with respect to laurussia leading to major plate and relieves reorganisation during permo triassic times pangea b using an atmospheric general circulation model agcm we simulate the climatic response to both configurations we also test the fundamental role of paleo elevations through sensitivity experiments each simulated climate is then compared with the aim of constraining the best fit to a particular paleogeographic scenario main trends of simulated late permian climate in agreement with paleoclimatic indicators are 1 a warm temperate climate accompanied by a monsoon circulation over the eastern side of gondwana 2 a cold temperate climate marked by strong annual thermal amplitude at high latitudes in gondwana and in siberia 3 an arid belt in the subtropics over the western side of gondwana and laurussia and 4 strong climatic differences over both hemispheres respectively main variance is found over laurussia with a simulated tropical climate while an arid climate is suggested by paleodata simulating different paleo elevations of the appalachian and the variscan fold belts can solve this discrepancy the best model data fit is reached for a mean altitude of 4500 m in the appalachians and appears to be dependent of pangea configuration with a southern europe variscan range of some 3000 m in a pangea a configuration or only 2000 m in for pangea b taking into account the geodynamic context we argue that pangea b appears to be the more probable configuration

prediction of some weathering trends of plutonic and volcanic rocks based on thermodynamic and kinetic considerations abstract the exposed crust consists mainly of plagioclase 35 quartz 20 k feldspar 11 volcanic glass 12 biotite 8 and muscovite 5 quartz is a resistate thus feldspars and glass represent approximately 75 percent of the labile minerals the weathering characteristics of these constituents are summarized in the context of thermodynamic mass balance and kinetic considerations experimentally determined release rate constants were used to predict the proportions of ca na and k released by feldspars of plutonic rocks granites to gabbros to weathering solutions the chemical weathering trends of the weathered residues calculated from the kinetic data conform closely to the initial trends observed in some recent weathering profiles demonstrating the accuracy of the predictions since the weathering of feldspars is controlled by processes that should not change through geological time the relative release rates of ca na and k from the feldspars of granitic rocks can be calculated for future and past episodes of continental weathering experimentally determined release rate constants are not available for a wide range of volcanic glass compositions but the limited data indicate that compositional trends are predictable in weathering profiles developed on volcanic rocks the kinetic data available for rhyolitic glasses accurately predict the initial weathering trends observed in a recent rhyolite weathering profile

genesis types and evolution of crevice type caves in the flysch belt of the western carpathians czech republic abstract crevice type caves are among the least investigated natural phenomena connected with the development of slope failures these caves present complex and peculiar underground systems with their own development and resulting landforms we investigated eight caves in the czech part of the outer western carpathians to determine their genesis types and evolution crevice formation is predisposed according to the lithological tectonic and morphological characteristics of the landslide body including the position and location of bedding planes joints and faults we performed several analyses including speleological mapping evaluation of high resolution topography above the caves geophysical ert measurements and structural investigations within cave passages in accordance with these analyses various mechanisms responsible for cave development were revealed an intra bed translation is responsible for the creation of regularly shaped passages with flat ceilings toppling as well as back and horizontal rotation of rock blocks determine the specific morphology and shapes of passages a relatively novel aspect of the current study is the identification of the subsidence of massive rock wedges due to the widening of cracks all of these mechanisms control the specific morphological characteristics within crevices e g typical shapes of passages cave level ordering and ceiling types some of these processes also influence topography above the caves finally the different phases of evolution of these caves were determined

crevice type caves as initial forms of rock landslide development in the flysch carpathians crevice type caves formed along joints are very common in the polish flysch carpathians more than 600 have been recorded the caves represent accessible parts of the widened cracks which are basic initial forms of development of deep seated rock landslides structural features of four selected caves situated in different parts of the carpathians were studied in order to determine relations between joint systems and landslide formation the studies prove that the main rock scarps often represent effects of earlier propagation of the cracks cutting surfaces due to loading and unloading shearing stress the cracks are structural forms developed along joints or faults the cutting surfaces represented by cracks caves develop a long time before the main gravitational mass movements whereas the sliding surfaces shearing zones are formed or significantly modified ad hoc during the gravitational transport of rock masses occurrence of the deep initial cracks causes modification of shape of the sliding surfaces which are noncircular the mountain slopes cut by many cracks are permanently developed thus the periodic increase of activity of external factors floods downpours earthquakes etc leads to common formation of the landslides earlier prepared by crack development this model of slope evolution enables us to interpret the occurrence of the landslide phases in the holocene during which increasing of frequency of the landslides is observed

structural constraints on deep seated slope deformation kinematics abstract a significant sackung type deep seated slope gravitational deformation dsgsd was recognised for the first time by the authors in the middle part of valfurva east of bormio rhaetian alps italy the reconstruction of its kinematics age and state of activity is presented through a detailed description of its morphological geomechanical and structural features an integrated multi disciplinary approach was performed to achieve a clear comprehension of the phenomenon field surveys and aero photo interpretation were carried out in order to clarify the structural geological and geomorphological setting in which the dsgsd developed a kinematic conceptual model of the slope deformation was developed through the analysis of morpho structures of their significance and relationships with lithological markers and quaternary deposits after a geomechanical characterisation of the rock mass involved in the slope deformation numerical modelling was performed to verify the hypotheses made on kinematics and driving factors of the phenomenon the sackung affects pre permian metapelites metabasites and marbles belonging to the upper austroalpine basement of the campo nappe as well as late pleistocene and holocene glacial and rock glacier deposits the deformation started after the late wurmian age 15 000 11 000 years b p and continued until few centuries ago not excluding a present day low rate activity deformation consists in a large oblique sagging along a deep confined sliding surface associated with gravitational reactivation of pre existing late alpine and recent tectonic brittle structures leading to the formation of n s and wnw ese trending gravitational morpho structures the evolution of the wnw ese trending system resulting in asymmetric trenches led to progressive failure of the lower part of the slope during the last 10 000 years as testified by large paleo landslide accumulations and it is still in progress numerical modelling indicates post glacial unloading as the main triggering factor of the slope deformation the importance of this deep seated slope deformation is enhanced by the occurrence of the 30 mm 3 active ruinon landslide in the lower part of the slope such landslide is subjected to rapid evolution and threatens the valley floor establishing an important risk factor connected to human lives and socio economic activities

geophysical investigation of a large landslide in glaciolacustrine clays in the trieves area french alps abstract slope movements in clay deposits are spread all over the world and result from complex deformation processes including internal strains in the landslide body and slipping along rupture surfaces such mass movements are likely to generate changes in the geophysical parameters characterizing the ground which can be used to map the landslide body in the last decade geophysical techniques have been increasingly used for landslide investigation purposes however the success of any geophysical technique is overall controlled by the existence of a geophysical contrast differentiating the body to be mapped for landslides affecting thick clay materials from soft clay to shale or marl electrical and seismic techniques have been mainly applied in the past in this study we attempt to physically characterize the deformation within a large slide avignonet affecting laminated clays which were deposited in a glacially dammed lake during the wurm period clay deposits which cover an area of 300 km2 south of grenoble french alps and have a maximum thickness of 200 m overlay compact alluvial layers and marly limestone of mesozoic age piezometric data at avignonet show that the water table is very shallow implying that the slide developed in saturated clay several seismic and electrical profiles were performed in order to tentatively correlate the variations of p wave vp velocity s wave velocity vs and electrical resistivity with geotechnical data and morphological observations in such saturated and fine material it turned out that only the s wave velocity exhibits significant variations with the displacement rates and the morphological features vs values at shallow depth were found to be inversely correlated with displacement rates measured by gps with a division by at least a factor of 2 between the zones unaffected and strongly deformed by the landslide these results suggest that vs mapping could provide valuable information on the deformation state of the clay material and that the evolution of vs with time could be used as an indicator for characterizing the landslide activity in the subsurface including the evolution into a flow

quantitative mineralogical characterization of karst bauxite deposits in the southern apennines italy the southern italian karst bauxite deposits occur at a late cretaceous hiatus on a bahamian type carbonate platform succession cropping out in the southern apennines and are mainly located in the abruzzi mountains in apulia gargano peninsula and murge area and in campania the bauxites of southern italy are presently uneconomic but can be considered as a model analogue for economic karst bauxite ores the texture of the bauxite deposits is mainly oolitic to pisolitic but can also be arenitic conglomeratic suggesting reworking of evolved lateritic soils the minerals boehmite and hematite are more abundant in the ooids whereas kaolinite is found at high levels in the groundmass and titanium oxides are also present furthermore small amounts of rare earth elements have been detected in most of the bauxite occurrences scanning electron microscopy with energy dispersive spectrometry sem eds and geochemical analyses on several of the deposits confirmed the diagenetic texture of the bauxite and provided an estimate of the mineralogy of the different components and their chemical composition the mineralogical and petrographic characteristics of bauxite are crucial for the bayer process and can influence its economic evaluation both the particle size distribution in the ore and the presence of reactive silica phases associated with ti and fe oxides can reduce the efficiency of processing quantitative analyses combining different methods x ray diffraction xrd rietveld quantitative phase analysis qpa and qemscan have been carried out on a limited number of samples from two of the bauxite districts of the campania region the matese mountains and the caserta province qemscan analysis allowed a more rapid quantification of mineralogy including trace detrital phases and assessment of the individual textural characteristics of the bauxite lithotypes showing a detailed image of the distribution of economic and noneconomic minerals and their intergrowths this methodology can augment or replace other time consuming quantitative phase analyses for mineralogical studies of bauxites provided that the species identification protocol sip database has been carefully validated by preliminary use of xrd and sem eds both xrd qpa and qemscan analytical techniques can be complementary for bauxite ore evaluation and a very powerful tool for exploitation and mineral processing

lacustrine carbonates and pedogenesis sedimentology and origin of palustrine deposits from the early cretaceous rupelo formation w cameros basin n spain the berriasian rupelo formation of the w cameros basin consists of a 2 200 m thickness of marginal and open lacustrine carbonate and associated deposits open lacustrine facies contain a non marine biota with abundant charophytes both stems and gyrogonites ostracods gastropods and rare vertebrates carbonate production was mainly biogenic the associated marginal lacustrine palustrine facies show strong indications of subaerial exposure and exhibit a wide variety of pedogenic fabrics silicified evaporites found near to the top of the sequence reflect a short hypersaline phase in the lake history the succession was laid down in a low gradient shallow lake complex characterized by wide fluctuations of the shoreline carbon and oxygen stable isotope analyses from the carbonates show non marine values with ranges of 13 from 7 to 11 and 18 from 3 to 7 5 differences in the isotopic composition of open lacustrine carbonates are consistent with sedimentary evidence of variation in organic productivity within the lake analyses from the entire sample suite plot on a linear trend isotopic compositions become lighter with increasing evidence of pedogenic modification this suggests progressive vadose zone diagenesis and influence of meteoric waters rich in soil derived co2 the stable isotope data thus support evidence from petrography and facies relations that palustrine limestones form through pedogenic modification of lake carbonates

cerium anomalies in lateritic profiles the ree geochemistry and mineralogy have been studied in four lateritic profiles one derived from a syenite akongo sw cameroon the others being developed on a gneissic basement and located along a soil toposequence goyoum e cameroon there is a fractionation between lree and hree in the lateritic samples during weathering the weathered residual products being enriched in lree from la to eu and depleted in hree from gd to lu sampled waters are enriched in hree in relation to the syenite host rock a positive ce anomaly has been found systematically at the top of the saprolite beneath a zone of iron oxide accumulation in the laterite up to 2000 ppm ce may be present in the akongo profile cerianite ceo2 is present as very fine coatings in non ferruginous clayey domains primary ree bearing accessory minerals are weathered at the bottom of the profile specifically allanite and apatite are transformed into florencite and rhabdophane but these phases have no ce anomaly all the data are interpreted as the result of the following processes 1 1 ree leaching in a reducing environment 2 2 oxidation of ce3 to ce4 in an oxidizing environment 3 3 deposition of cerium as cerianite whereas the other ree remain in solution

the fate of chromium during tropical weathering a laterite profile from central madagascar abstract we performed a mineral geochemical and cr sr pb isotope study on a laterite profile developed on ca 540 ma old tonalitic bedrock in madagascar with special emphasis on the behavior of chromium during tropical weathering the observed strong depletions of ca si and p and enrichment of fe and al in the soil relative to bedrock and underlying saprolite are the characteristic features pertinent to laterites the enrichment of fe in topsoil horizon can be correlated with enrichment of p and the redox sensitive elements mn and cr and indicates redistribution of these elements related to oxidation reduction processes the slight scatter of 87sr 86sr and 206 207 208pb 204pb values in the profile is one consequence of such redistribution processes our results are compatible with a two stage process during alteration 1 an incipient alteration stage characterized mainly by a pervasive effective and complete loss of sulfides accompanied by patchy alteration constrained along fissures and cracks and 2 a main stage of soil formation actual laterization with loss of na k ca and si and accumulation of fe and mn relative to the unaltered bedrock this two stage evolution is also depicted by cr concentrations and 53cr values along the studied profile where the first incipient alteration stage caused a pronounced depletion of cr particularly hosted by sulfides and where the second alteration laterization led to redistribution and a small increase in cr concentration in the uppermost portions of the soil profile relative to stage one altered saprolite this gain in cr is accompanied by decreasing 53cr values and can be explained by partial immobilization possibly by adsorption coprecipitation on with fe oxy hydroxides of mobile cr iii during upward transport in the weathering profile the negatively fractionated 53cr values measured in the weathering profile relative to the unaltered tonalitic bedrock characterized by a high temperature magmatic inventory cr isotope signature are consistent with loss of a positively fractionated cr vi pool formed during weathering the predicted existence of a former positively fractionated and mobile chromium pool has been experimentally constrained in circumneutral and basic leachates of powdered tonalite bedrock where 53cr of 0 21 to 0 48 was measured our results show that mobilization of chromium is effective under highly oxidative conditions which in well drained sulfide bearing parent bedrocks potentially lead to both acid dissolution of sulfide hosted cr and redox promoted mobilization of cr vi from silicates during later stages of weathering under basic ph conditions

large landslides and deep seated gravitational slope deformations in the czech flysch carpathians new lidar based inventory abstract moderate relief landscapes such as the czech flysch outer western carpathians cowc in comparison with alpine regions are rarely subject to extensive landslide inventory mapping an understanding of landslides in such a landscape is needed because densely populated hilly landscapes in temperate zones are usually of major socio economic importance in this study we performed the first lidar based landslide mapping for the entire cowc area 7539 km2 one of the most landslide prone regions in europe by calculating various landscape and landslide metrics we infer the distribution frequency area relationships kinematics and controls of mass movements with special attention on large landslides 0 1 km2 and deep seated gravitational slope deformations dsgsds we mapped a total of 13 611 landslides of which 1357 failures are large landslides and dsgsds whereas the lower and more subdued areas in the southern part of cowc are hotspots in terms of the total number of landslides the higher and more topographically pronounced areas in the northeast are affected predominantly by large landslides and dsgsds however landslides with 0 1 km2 are widespread throughout the whole territory of cowc a discrepancy also exists in the spatial distribution of different types of landslides rock slides and dsgsds are dominant in the north east while flow type landslides are dominant in the southern lower topographic relief with claystone dominated flysch we conclude that 1 distinct geological units nappes produce landslide populations with different frequency area distributions 2 stratigraphic composition alongside the tectonic style of flysch formations control the type of landslides 3 dsgsds affect mainly slopes formed by rigid rocks sitting atop soft formations and 4 geological conditions rather than topography control distribution of large landslides and dsgsds in cowc

from deep seated slope deformation to rock avalanche destabilization and transportation models of the sierre landslide switzerland abstract sackung is a widespread post glacial morphological feature affecting alpine mountains and creating characteristic geomorphological expression that can be detected from topography over long time evolution internal deformation can lead to the formation of rapidly moving phenomena such as a rock slide or rock avalanche in this study a detailed description of the sierre rock avalanche sw switzerland is presented this convex shaped postglacial instability is one of the larger rock avalanche in the alps involving more than 1 5 billion m3 with a run out distance of about 14 km and extremely low fahrboschung angle this study presents comprehensive analyses of the structural and geological characteristics leading to the development of the sierre rock avalanche in particular by combining field observations digital elevation model analyses and numerical modelling the strong influence of both ductile and brittle tectonic structures on the failure mechanism and on the failure surface geometry is highlighted the detection of pre failure deformation indicates that the development of the rock avalanche corresponds to the last evolutionary stage of a pre existing deep seated gravitational slope instability these analyses accompanied by the dating and the characterization of rock avalanche deposits allow the proposal of a destabilization model that clarifies the different phases leading to the development of the sierre rock avalanche

estimating depth of investigation in dc resistivity and ip surveys in this paper the term depth of investigation refers generically to the depth below which surface data are insensitive to the value of the physical property of the earth estimates of this depth for dc resistivity and induced polarization ip surveys are essential when interpreting models obtained from any inversion because structure beneath that depth should not be interpreted geologically we advocate carrying out a limited exploration of model space to generate a few models that have minimum structure and that differ substantially from the final model used for interpretation visual assessment of these models often provides answers about existence of deeper structures differences between the models can be quantified into a depth of investigation doi index that can be displayed with the model used for interpretation an explicit algorithm for evaluating the doi is presented the doi curves are somewhat dependent upon the parameters used to generate the different models but the results are robust

genesis of the guangou karstic bauxite deposit in western henan china abstract the guangou bauxite deposit in western henan china is located in the north china block and to the north of the north qinling orogenic belt the orebody is hosted within the lower member of the carboniferous benxi formation which overlies unconformably upon the ordovician majiagou formation in the lower member of the benxi formation the bauxite orebody with a diaspore illite anatase mineral assemblage is sandwiched between underlying ferric clay illite hematite goethite and overlying top clay kaolinite quartz goethite according to field observations and geochemical evidence including trace and rare earth element ree compositions especially zr hf ratios the ferric clays were weathered from the underlying argillaceous limestones in the majiagou formation during this weathering process trace elements s zn ni cr v sc f ba and be are depleted li rb and b are enriched and zr hf bi ta ga nb and th are relatively immobile rees exhibit evident differentiation with enrichment of la ce pr and nd and depletion of gd tb dy ho er tm yb and lu the bauxite formed in weak reducing slightly basic water conditions according to the geneses of coexisting diaspore and anatase and it was altered during the epigenetic and second exposure periods forming kaolinite and goethite respectively interelemental relationship analyses of the ores suggest that the elemental behaviors of trace elements and rees in the bauxitization process are mainly controlled by the mineral compositions in bauxite ore and chemical properties of the elements for instance zircon rutile and anatase contain zr hf nb ta w and u based on geochemical evidence together with age data and chemical compositions of the detrital minerals both distant igneous rocks in the plate margin and paleozoic carbonates and precambrian rocks inside north china block provide the miscellaneous material for the bauxite ore and the top clay

deep seated gravitational slope deformations in the highest parts of the czech flysch carpathians evolutionary model based on kinematic analysis electrical imaging and trenching deep seated gravitational slope deformations dsgsds played an important role during the quaternary evolution of mountain ridges formed by anisotropic flysch rocks of the outer western carpathians owc four dsgsd affected ridges in the highest part of the czech sector of the owc have been subjected to multidisciplinary investigation involving mapping structural and kinematic analysis geoelectrical imaging trenching and dating all the studied dsgsds are strongly predisposed by regional structural fabric given by the intersection of bedding planes joint sets and faults performed research suggests high diversity of mechanisms leading to the origin of individual dsgsds the area of a single dsgsd can be affected by various types of movements such as sackung lateral spreading toppling or incipient sliding electrical imaging and trenching revealed that besides these mechanisms anisotropic flysch massifs formed by thick bedded sandstones are strongly exposed to subsurface opening of air filled voids related to widened crevices such a process is driven by deep seated creep and translational sliding of sandstone beds upon plastic claystones whose strength has been reduced to residual values of the angle of internal friction performed radiocarbon and osl dating revealed that some of the studied dsgsds originated in the holocene period particularly in the atlantic and subboreal chronozones

development of deep seated gravitational slope deformation on a shale dip slope observations from high quality drill cores abstract we analyzed high quality drill cores with 100 recovery drilled into a gravitationally deformed dip slope of a shale dominated sequence of sediments in japan the slope had undulating surfaces but no well defined landslide scarps suggesting that parts of the slope had undergone gravitational deformation but had not completely separated from the surrounding bedrock the gravitational deformation of shale and sandstone is characterized by disintegration and brecciation of sediments and the formation of pulverized zones with poorly developed planar structures jigsaw like structures and fracture openings shear zones are distributed intermittently within the slope but have not merged discernably into a through going master sliding surface incipient landslide shear zones form openings within coherent rock by shearing along bedding with these shear zones potentially developing downward in a stepwise manner which may be related to stress redistribution induced by river incision

structural control and types of movements of rock mass in anisotropic rocks case studies in the polish flysch carpathians abstract types of gravitational movements in the flysch carpathians are related to tectonic and lithologic anisotropy of rock massifs this article presents the main types of mass movements in the highly anisotropic flysch massifs lateral spreading and rock flow topple translational rotational and compound sliding and complex type of mass movements which are illustrated by chosen forms described using structural analysis joints faults and other structural planes orientation topple is the typical mass movement for double ridges and top trenches e g gaworzyna in the beskid s decki mts translational landslides with flat structural sliding surfaces typical for shallow forms can develop along bedding planes e g duszatyn western bieszczady mts as well as along joints opuszna gorce mts and fault planes rzeki gorce mts currently used classification of the structural landslides is applied only to translational landslides shearing zones of deep seated landslides are composed of structural sections of joints faults bedding planes and shearing elements consequently most of the carpathian landslides have developed as compound type with non circular sliding zones representing complex movements combined with various types of displacement rotation translation and or topple purely rotational movements with circular failure typical for isotropic material have developed in the flysch where thick bedded hard sandstones are underlain by plastic shales e g mt kostrza in the beskid wyspowy mts the influence of anisotropy of these rocks on sliding surface is significantly reduced and plastic type rocks stimulate rock flow development which is usually later transformed into complex landslides with predominant rotational movement e g rotational landslide with topple and flow elements on mt muronka in the beskid l ski mts compound landsliding on mt lubon wielki beskid wyspowy mts represents an antithetic rotational slide with topple and rotational type movements

deep geophysical investigation of the large sechilienne landslide western alps france and calibration with geological data a geophysical imaging campaign including four 950 m electrical profiles and four 470 m long seismic profiles was performed on the large sechilienne landslide with the objective of constraining the depth and the volume of the affected zone compared to the undisturbed ground the moving area exhibits lower velocity and higher resistivity values comparison with existing geodetic geomorphic and geological data investigation gallery and borehole allowed showing that these geophysical parameter variations result from intense fracturing and the progressive development of air filled voids within the moving mass a maximum thickness of 150 m to 200 m was found in the most deconsolidated zones locally near vertical very low resistivity anomalies were evidenced related to cataclasis zones filled with clayey material applying the wyllie s experimental law rock mass porosity images were derived from seismic tomography profiles porosity between 30 and 4 was found from the top to the bottom of the deconsolidated zone explaining the deep water table considering a porosity threshold of 3 7 for the sound bedrock the total volume of the sechilienne landslide was estimated to about 60 10 106 m3 a more precise bracket than the previous estimations 20 106 to 100 106 m3

the vertebrate track record a renaissance in the study of fossil footprints has been driven by a multitude of discoveries and the realization that vertebrate ichnology makes important contributions to our understanding of terrestrial vertebrates more striking is the insight the track record gives us into bias and incompleteness in the vertebrate fossil record

deep seated gravitational slope deformations controlled by the structure of flysch nappe outliers insights from large scale electrical resistivity tomography survey and lidar mapping abstract the flysch nappe outliers represent a structural setting prone to the development of deep seated gravitational slope deformations dsgsds the study area of the palkovicke h rky hills represents an isolated outlier of the carpathians flysch nappes czech republic geomorphological mapping based on field surveys and interpretation of lidar data reveals the occurrence of various types of slope deformations including two dsgsds with the aim of detecting the main controlling factors of the dsgsds a multiapproach investigation combining surface and underground studies has been performed structural measurement points to a brachysynclinal structure composed of jointed and lithologically diverse strata with step like topography high resolution lidar data suggest strong tectonic disruption caused by conjugated transtensional and en echelon tectonic faults controlling the course of slope segments river valleys and landslide scarps four specific localities have been subjected to geophysical surveying kilometre scale electrical resistivity tomography ert profiles that have depths of penetration reaching the limits of the method 150 m were acquired across the gravitationally deformed nappe outlier the data show the overall structural conditions of the nappe outlier consisting of alternating lithological units affected by folds and fault zones a local subordinate anticline within the central part of the brachysynclinal structure has controlled the origin of the most morphologically pronounced dsgsds other large scale dsgsds related to the inherited fault system potentially affect the entire n nw segment of the studied elevation data integration indicate that structural conditions including lithological boundaries tectonic disruption and local folding to be the main controlling factors of the dsgsds evolution

tectonic strain changes affecting the development of deep seated gravitational slope deformations in the bohemian massif and outer western carpathians abstract this paper describes a pair of intensively studied deep seated gravitational slope deformations from the czech republic structural geological mapping and the interrogation of high resolution lidar dems have been used to reassess the extent of each slope deformation and to obtain new information about their surface morphologies electrical resistivity tomography has been used to image the subsurface structures while rod dilatometers and permanently installed mechanical extensometers have been used to define their kinematic behaviour dilatometric measurements from across a fissure the edge of the mu sk hill dsgsd show that the progressive trend has been interspersed by five periods of movement acceleration since monitoring began in 1990 while extensometric measurements from across a second fissure about 50 m from the edge of the plateau show that this discontinuity was affected by an significant period of extension from 2004 to 2006 and a significant period of compression from 2006 to 2008 these data demonstrate that the mu sk hill dsgsd is characterised by the lateral spreading of rigid sandstone blocks across a plastic marl formation at the edge of p ihrazy plateau extensometric measurements from the kn hyn mountain dsgsd show that a fault located at a depth of about 25 m below the surface is characterised by progressive dilation whereas a fault located at a depth of about 57 5 m below the surface is characterised by episodic vertical dip slip displacements both faults are affected by horizontal dextral strike slip displacements these data demonstrate that the kn hyn mountain dsgsd is characterised by translational rocksliding associated with the neotectonic uplift of the outer western carpathians the presented kinematic data have been compared to records of precipitation groundwater level earthquakes and strain changes measured by the fault displacement monitoring network eu tecnet strain changes induced by the widespread redistribution of stress through the crustal appear to represent an important and hitherto underappreciated geomorphological process affecting the development of the slope deformations at mu sk hill and kn hyn mountain future research will focus discovering whether this finding holds true for other deep seated gravitational slope deformations in different geomorphological and geological settings

reconstruction of landslide movements using digital elevation model and electrical resistivity tomography analysis in the polish outer carpathians abstract landslides are a major threat to the environment infrastructure and human activities especially in mountainous and hilly areas it is therefore important to accurately identify the mass movements triggering these mechanisms this paper presents the impacts of lithotectonic conditions on the formation of mass movements on the example of the landslide that is located in the northern part of the polish outer carpathians in the area of the research the ratio of the total area of landslides to the surface of the area reaches even 20 the interpretation of a high resolution digital elevation model dem electrical resistivity tomography ert and fieldwork results allowed for the reconstruction of the landslide movements and dividing them into two areas the western one dominated by rotational movement and the eastern one featuring rotational and translational movement it was found that the eastern part is more active now as it probably was also in the past which might have resulted from the lithotectonic conditioned or from the impact of the flowing waters of the dunajec river moreover in the eastern part of the landslides a small sized ridge 55 m 25 m was identified which shows greater stability in comparison with the colluvium that surrounds it in order to explain the lower rate of movement of this landform a morphometric analysis and research using ert were performed the geophysical measurements showed that the ridge comprised rock formations of greater resistivity than its surroundings it is most likely that the only preserved sandstone packet constituting the original secondary escarpment became separated from the bedrock due to rotational movement the presented studies indicate that the landslide was created due to geological and atmospheric conditions a clear revival of landslide movements took place after significant precipitation events that last occurred in the years 2010 and 2015 the bedrock substrate due to its lithology and tectonics facilitates these movements it was found that the landslide studied is a complex entity characteristic of the polish outer carpathians that has undergone multiple stages of development the landslide is active or periodically active and therefore must be excluded from the planned development as well as from other forms of human activity

the ciw index a new chemical index of weathering abstract a new chemical index of weathering that can be applied to modern soils and precambrian paleosis is proposed ciw al2o3 the value of this index increases as the degree of weathering increases and the difference between ciw index values of the silicate parent rock and soil or sediment reflects the amount of weathering experienced by the weathered material

regional mapping and characterisation of old landslides in hilly regions using lidar based imagery in southern flanders abstract analysis of lidar derived imagery led to the discovery of more than 330 pre holocene to recent landslides in southern flanders 4850 km 2 the morphology of three landslides including the 266 5 ha deep seated gravitational slope deformation in alden biesen was investigated in more detail the analysis of the morphological and topographical characteristics width length relation frequency area distribution and topographical threshold of the landslides revealed important differences compared to the characteristics reported in other landslide studies and helped understanding possible landslide triggering mechanisms especially the possibility of a seismic origin of the landslides was investigated finally a heuristic model for region wide landslide susceptibility mapping was successfully tested the susceptibility model and map allow prediction of future landslide locations and contribute to better understanding the role of individual causal factors on landslide location and spatial density the results suggest that landslides on low gradient soil mantled hills are a more important contributor to landscape evolution of hilly areas than was hitherto thought the morphology of all hilly regions of flanders is clearly marked by landslide processes and higher landslide densities often coincide with the presence of quaternary active faults this study further shows that high resolution topographical data such as lidar significantly contributes to a better detection of old previously unknown landslides

geochemistry and secular trends in the middle late permian karst bauxite deposits northwestern iran abstract this study focuses on the middle late permian bauxite deposits found within karstic depressions and sinkholes of carbonates of the ruteh and nessen formations northwestern iran data concerning five karst bauxite deposits each related to a different stratigraphic position within the bedrock were selected to address the chemical distribution and inter elemental relationships especially for critical elements factors that control bauxite formation and the parental affinity the analyzed samples mainly clayey bauxite and bauxitic clay are characterized by large compositional fluctuations involving both major and trace elements the major element composition is dominated by sio2 tio2 al2o3 and fe2o3 among the critical elements compositional fluctuations induce the occurrence of outliers for co nb ta lree and hree similar to other trace elements such as ba sr cr u and zr elemental mobility indicates that most of elements are generally depleted among the critical elements co is enriched only in several samples of the older deposits and ree are enriched in some samples of the younger deposits factor analysis suggests that due to the observed al ga covariance fairly acidic conditions were never attained during bauxitization and that detrital resistant minerals concentrated during a bauxitization stage promoting al ti accumulation furthermore the u co variance with low soluble elements nb ta and th suggests that u was mostly conservative during the formation of deposits cobalt co varies with cr and these elements accumulated during later bauxitization stages when the massive leaching of silica occurred the cia ciw and pia paleo weathering proxies indicate an upward weathering increase which suggests a trend toward more extreme weathering conditions in a wetter and warmer climate according to the permian global warming this is consistent with an upward increasing ba sr ratio and the inspection of the a cn k plot where the younger deposits fall close to the a k edge involving a clayey precursor requires a rainfall increase interestingly the upward trend toward a warmer and wetter climate was also coupled with paleo redox conditions promoting cerium oxidation as depicted by the ce ce values finally the eu anomaly and the sm nd ratio indicate that the studied bauxite deposits were mainly derived from a mafic protolith that formed in the middle late permian as a consequence of the volcanism that affected the entire iranian platform a cluster of karst bauxites however has eu eu values lower than the average standard deviation range of the mafic rocks suggesting a possible contribution of a more differentiated and less mafic protolith similarly the u th ratio at large supports the hypothesis of a mafic protolith for the middle late permian bauxite deposits although some samples show the u th values well above the average standard deviation range of the mafic rocks likely indicating that processes promoting the accumulation of resistant minerals with high u th ratios cannot be excluded this means that in this case the u th ratio does not necessarily reflect the protolith of karst bauxites and that more in general this proxy needs to be carefully interpreted when used to assess the parental affinity of residual rocks

influence of structural framework on mountain slope deformation in the maiella anticline central apennines italy abstract relationships between tectonic framework and gravity driven phenomena have been investigated in an area of the central apennines italy characterised by high relief the north south half dome shaped maiella anticline lies in the easternmost part of the apennine fold and thrust belt its backlimb is bordered by the caramanico fault a normal fault with a maximum downthrown of about 3 5 km that separates the western slope of the maiella massif from the caramanico valley the southwestern maiella area is affected by deep seated gravitational slope deformation indicated by major double crest lines down hill and up hill facing scarps a pattern of crossing trenches bulging at the base of slopes and the presence of different types of landslide and talus slope deposits the onset and development of deep seated gravitational slope deformations and the location of quaternary massive rockslope failures have been strongly influenced by the structural framework and tectonic pattern of the anticline deep seated gravitational slope deformation at mt macellaro mt amaro ridge has developed along the maiella western reverse slope in correspondence with the anticline axial culmination it is bordered at the rear by a nnw sse oriented dextral strike slip fault zone and has an e w direction of rock mass deformation closer to the southern plunging area of the anticline gravity driven phenomena show instead a n s and nw se direction influenced by bedding attitude 3d topographic models illustrate the relationship between deep seated gravitational slope deformation and massive rockslope failures the campo di giove rock avalanche a huge quaternary failure event was the result of an instantaneous collapse on a mountaine slope affected by a long term gravity driven deformation

geochemistry of the apulian karst bauxites southern italy chemical fractionation and parental affinities article i nfo this study focuses on a late cretaceous karst bauxite deposit in the murge area of the apulia district southern italy the first analysis of the vertical distributions of a wide range of elements including rees and selected trace elements throughout the deposit was shown in order to identify the processes determining element frac tionation during the evolution of the bauxite the studied karst bauxite deposit exhibits an ooidal texture is mineralogically homogeneous and contains higher abundances of boehmite than of hematite kaolinite and anatase the major element composition of the bauxite is dominated by elevated concentrations of sio2 t io2 a l2o3 a nd fe2o3 and analyses of element mo bility within the bauxite indicate that all elements except for nb and ni and to a lesser extent cr are depleted relative to the immobile element ti r mode factor analysis revealed a number of key findings i some low solubility elements e g zr th ti v ga were concentrated in detrital zircon and monazite zr th in anatase ti v and possibly in boehmite and hematite ga during the later stages of bauxitisation ii fe and cr were concentrated during wet conditions whereas al and co accumulated during dry conditions iii distributions of the light rees lrees and the heavy rees hrees are controlled by the same processes suggesting that little lree hree fractionation occurred during bauxite formation and iv the behaviour of cerium is different from that of the other rees and highly variable cerium anomalies are observed across the deposit with three characteristic ce ce maxima with values ofn2 parisite was the only authigenic cerium mineral detected during this study thus we propose a three step model to explain the distribution of ce cerianite is dissolved by cerium reduction is transported by downward moving meteoric water per descensum and finally parisite is precipi tated this cycle was repeated several times in the apulian karst bauxite in response to eh decreases under alka line conditions promoted by fluctuations in the groundwater level finally we used the value of the eu anomaly todiscuss theparental affinity or protolith of thebauxite the value of the eu anomaly min eu eu 0 76 max eu eu 0 89 indicates that the bauxite was not derived from carbonates but rather that the majority of the bauxite was influenced by intermediate to mafic magmatic sources eu eu vs sm nd diagram suggests that the parental material for the bauxite was derived from a combination of a distant magmatic source and clastic material derived from a continental margin northern africa to the south

new evidence of xiphosurids from the middle jurassic of morocco palaeoenvironmental palaeoecological and palaeobiogeographical implications abstract horseshoe crabs chelicerata xiphosura from mesozoic deposits are extremely rare in the fossil record of the african continent here we report new evidence of the occurrence of xiphosurans in north africa these are horseshoe crab traces including the ichnogenera kouphichnium repichnia and selenichnites fodinichnia and or domichnia which have been discovered in middle jurassic strata of the imilchil area central high atlas morocco they are preserved on upper and lower bed surfaces of sandy limestones and marls in the upper parts of the tislit and imilchil formations late bajocian early bathonian the selenichnites traces measuring up to 30 cm in width co occur with theropod and birdlike tracks the reported kouphichnium is the first record from mesozoic deposits of morocco while selenichnites is the second occurrence in jurassic strata of africa these ichnogenera evidence different behaviour of horseshoe crabs i e selenichnites is the result of burrowing activity when searching for food in the sediment and kouphichnium is a regular locomotion trace left on the sediment surface occasionally leaving an impression of the telson the combination of sedimentological data and ichnological analysis indicates a shallow water subtidal depositional environment preceding the bathonian regression of the atlas domain palaeobiogeographically the discoveries indicate the presence of horseshoe crabs at the southern margin of the tethys furthermore they enhance our knowledge of their previously scarcely documented distribution in gondwana during the mesozoic

genetic relationship between the emeishan plume and the bauxite deposits in western guangxi china constraints from u pb and lu hf isotopes of the detrital zircons in bauxite ores abstract the formation processes and alumina sources of the large and super large bauxite deposits that have developed in west guangxi in the yangtze block have been debated for a long time shrimp zircon u pb dates combined with in situ hf isotopic data of the detrital zircons from permian bauxite ores in the western guangxi province china provide new constraints on the genesis of the bauxites in west guangxi u pb dating ages of the detrital zircons cluster around 256 ma and 261 ma this is consistent with the emplacement age of the emeishan plume thus it has been determined that the detrital zircons come from magmatic rocks related to the emeishan plume and that the emeishan plume has significant control on the formation of bauxites in addition this work presents new evidence for the evolution of the emeishan plume most of the e hf t values of the zircons around 256 ma and 261 ma are negative varying widely from 1 3 to 16 1 this data indicates the melting of yangtze block basement rocks and the mixing of magmas generated both from the mantle and from the crust occurred at the periphery of the plume in the main phase of emeishan lip magmatism this study verified that the plume induced uplift exposed carbonates as well as the mafic and felsic rocks generated by the emeishan plume to long periods of intense weathering under humid tropical conditions the weathering remnants of the high alumina magmatic rocks and carbonates were deposited on or transported to the paleokarst surface and converted to bauxites

electrical resistivity tomography technique for landslide investigation a review abstract in the context of in situ geophysical methods the electrical resistivity tomography ert is widely used for the near surface exploration of landslide areas characterized by a complex geological setting over the last decade the technological improvements in field data acquisition systems and the development of novel algorithms for tomographic inversion have made this technique more suitable for studying landslide areas with a particular attention to the rotational translational and earth flow slides this paper aims to present a review of the main results obtained by applying ert for the investigation of a wide spectrum of landslide phenomena which affected various geological formations and occurred in different geographic areas in particular significant and representative results obtained by applying 2d and 3d ert are analyzed highlighting the advantages and drawbacks of this geophysical technique finally recent applications of the time lapse ert tl ert for landslide investigation and the future scientific challenges to be faced are presented and discussed

deep seated gravitational slope deformations along the active bocono fault in the central portion of the merida andes western venezuela abstract two very large deep seated gravitational slope deformations in the highlands of the merida andes venezuela are herein described the mucubaji pass and cerro la camacha these slope movements have slid in post last glacial maximum times in addition both landslides are in very close association with the active bocono fault trace the cerro la camacha camacha range landslide is fault bounded along its northwest flank whereas the mucubaji pass mass movement is even cut by the active fault trace the almost 10 km long mucubaji slide mobilizes lgm moraine deposits along the unconformable basement contact la camacha slope movement is a sackung type landslide involving two huge masses that affect the entire northwestern slope of the la camacha range this sackung is at least 20 km long paralleling the active bocono fault trace combination of high relief energy gravitational forces and seismic shaking related to an on site active fault could be responsible for the destabilization of the slopes or massif in both cases although the seismically induced re activation of the la camacha landslide is very likely there is no proof for that yet conversely the mucubaji slide shows geomorphic geodetic and sedimentary evidence of episodic activity in recent times which could be ascribed to seismic triggering in the particular case of the la camacha sackung the combination of dextral slip along the bocono fault and a se dipping fault plane could additionally favor the destabilization of the nw slope of the la camacha range

new grounds for reassessing palaeoclimate of the sirius group antarctica fossil nothofagus leaves from the meyer desert formation of the sirius group in the central transantarctic mountains have been found with recycled marine diatoms indicating that they are no older than 4 1 3 1 ma they have been interpreted as evidence for pliocene warming and diminution of the east antarctic ice cap in contrast plio pleistocene ice cap stability and sustained polar palaeoclimate has been argued from landforms in victoria land and isotopic data from the southern ocean new evidence on this question comes from fossil soils in the meyer desert formation one of these the siesta palaeosol has a gypsic horizon at a depth of 85 cm as in soils of polar deserts with a mean annual precipitation map of 120 220 mm clastic dykes from a 60 80 cm thick permafrost active layer in the palaeosols are evidence of a mean annual temperature mat of 3 to 11 c this is warmer and wetter than the dominion range today map 36 mm mat 39 c but still a periglacial climate cooler and drier than southern chilean moorland and krummholz map 600 7500 mm mat 5 8 c or subantarctic tundra map 400 2500 mm mat 5 to 5 c a pliocene age for the nothofagus fossils and siesta palaeosol is compatible with soil development on surfaces that bracket their enclosing deposits the dominion range was significantly warmer and wetter than it is today during pliocene c 3 5 ma growth of nothofagus and formation of the siesta palaeosol but the beardmore glacier was still large at that time surface soils and palaeosols of the meyer desert formation are evidence of another warmer and wetter episode earlier during the pliocene c 5 ma both warm intervals were separated by intervening times of glacial expansion and frigid palaeoclimate

temporal behavior of deep seated gravitational slope deformations a review abstract deep seated gravitational slope deformations dsgsds are slow moving hillslope scale mass movements featuring characteristic landforms such as double crested ridges and upslope facing scarps that occur in diverse landscapes throughout the world although these deformations have been studied since the 1960s significant insights to the rates of dsgsds have only been gained within the last two decades owing to progress in geochronology remote sensing and instrumental monitoring absolute age and monitoring data indicate that dsgsd movements are observable over long term 102 years and short term future research directions include constraining the lifespan of dsgsds with absolute age dating and precise high resolution monitoring of spatio temporal displacement across dsgsd bodies it is of great importance to include absolute time scales in the numerical models of dsgsds furthermore combining remote sensing techniques such as synthetic aperture radar interferometry with high resolution lidar scanning and near surface geophysics offers a promising toolkit for collecting very detailed and accurate data on the short term deformation rates of dsgsds

large sackung along major tectonic features in the central italian alps deep seated gravitational slope deformation sackung is common in alpine mountain belts it is controlled by lithological geomorphological and structural features we describe and discuss five examples of dsgsd along the insubric line periadriatic fault in the central italian alps the five examples are different in morphology size state of activity and distribution and are located along both primary and secondary valleys we demonstrate relations between structural and gravitational features and discuss the possibility that structural has both passive and active roles in sackung development analysis of ps sar data shows that the studied examples are not active today numerical modelling demonstrates the importance of lithological and structural constraints postglacial debuttressing groundwater fluctuations and weathering on sackung triggering and development

geomorphology and geophysics based recognition of stages of deep seated slope deformation sudetes sw poland abstract slopes of the kamienne mountains sw poland have been affected by a variety of slope deformations from dsgsds through rock slope collapses rotational and translational landslides sensu stricto to valley confined earth flows variable geomorphic expression suggests that major slope deformation events are of different ages and some slope deformation may be ongoing in this paper we use the combination of landform mapping and electrical resistivity tomography profiling to characterize two settings considered to represent early stages of slope deformation and advanced stages of ridge collapse landform recognition involved field geomorphic mapping and interpretation of high resolution lidar dtm diagnostic features of early stages of deformation are open cracks minor and rather subdued scarps in the upper slope and lower slope bulging irregular hummocky topography ruiniform relief and closed depressions typify the late stages ert results are generally consistent landform interpretation and show weakening of bedrock evolving failure planes as well as subsidence of rigid caprock blocks into deformable sedimentary series for the late stage the combined geomorphological geophysical approach performed fairly satisfactorily and both methods can be used to cross check interpretations even in areas not subject to recent mass movement events poorly accessible due to dense forest cover and lacking clear morphological evidence

geophysical anatomy of counter slope scarps in sedimentary flysch rocks outer western carpathians abstract a multidisciplinary geophysical survey consisting of electrical resistivity tomography ert ground penetrating radar gpr shallow seismic refraction ssr and gravity survey gs was used to investigate the counter slope scarps one of the typical manifestations of the relaxed zones of rock massifs and the possible initial stages of deep seated landslides dsls two upper parts of the extensive dsls within the moravskoslezske beskydy mountains outer western carpathians owc built by the sedimentary flysch rock were chosen as the testing sites a combined geophysical survey on the flysch rocks was performed on both localities to enhance our present findings the survey revealed that the ert is able to reliably detect underground discontinuities which are manifested at the ground surface by one of the typical landforms tension cracks trenches pseudokarst sinkholes double crested ridges and counter slope scarps previous studies suggested that bedrock discontinuities should be depicted by high resistivity features within ert surveying according to ssr and gs expected zones of weakened rock massif were not confirmed directly underneath the superficial landforms but they were shifted based on the ssr and gs measurements the depicted high contrast transitions between high and low resistivity domains within the ert profiles were newly identified as possible manifestation of bedrock discontinuities the results of gpr measurements give only limited information on the sedimentary flysch rocks due to shallow penetrating depth and locally strong signal attenuation the combined results of multidisciplinary geophysical surveying confirmed an importance of employing more than one geophysical technique for integrated interpretations of measured data integrated interpretations of the measured geophysical data provided a new insight into massif disintegration and the geomorphic origin of the landforms related to the dsl

crocodylomorph turtle and mammal tracks in dinosaur dominated middle upper jurassic and mid cretaceous ichnoassemblages of morocco abstract we report tetrapod traces from two stratigraphic intervals in morocco and discuss their palaeoecological implications in the first interval crocodylomorph footprints assigned to crocodylopodus meijidei are described from middle upper jurassic continental fluvial red beds of the isli formation in the imilchil region central high atlas morocco these traces are associated with a diverse dinosaur dominated ichnofauna including the footprints of theropods ornithischians sauropods and pterosaurs together with numerous invertebrate traces in the second interval we report crocodylomorph swim traces assigned to hatcherichnus isp turtle trackways assigned to emydhipus isp and isolated mammal footprints in the mid cretaceous midelt formation in the high moulouya region morocco these traces are also associated with a diverse dinosaur dominated ichnofauna including theropods and ornithopods as well as pterosaurs and abundant invertebrate traces together with plant remains conchostracans and fishes findings indicate a diverse community populating a fluvial brackish environment

argillite debris converted to bauxite during karst weathering evidence from immobile element geochemistry at the olmedo deposit sardinia the olmedo bauxite deposit occurs in the nurra district of northwest sardinia it forms a stratiform horizon in cretaceous limestone and marl uplift in mid cretaceous had exposed recently deposited limestone to karst weathering and a layer of argillaceous debris accumulated on its surface and was partly converted to bauxite intermediate products were desiccated marl bauxitic argillite and argillaceous bauxite subsidence followed and the bauxite was preserved by the deposition of late cretaceous limestone and other sediments uplift in oligocene miocene time with ensuing erosion exposed the bauxite horizon to its present configuration concentrations of normative minerals illustrate chemical processes and the build up of al in the bauxite horizon plots of chemical data and correlation coefficients show that al ti zr nb th cr and v were immobile during the bauxitization process mass changes point to large net removal of si mg and k from the system although some of this material and slightly mobile al were reprecipitated in the underlying argillite and altered marl immobile element ratios trace the source of the bauxite to the underlying argillaceous limestone al in the bauxite was accumulated from the degradation of 25 to 50 m of the argillaceous limestone

deep seated gravitational slope deformations in western sicily controlling factors triggering mechanisms and morphoevolutionary models abstract a study of deep seated gravitational slope deformation dsgsd phenomena affecting areas of various geological and geomorphological settings in western sicily is described western sicily is underlain by a thin skinned imbricate wedge of meso cenozoic carbonate and siliciclastic rocks that formed by the stacking of several thrust nappes over the iblean foreland locally the original thrust sheets are folded and cut by high angle faults large areas of western sicily now display high relief energy due to plio pleistocene block faulting and uplifting and the quaternary morphogenetic phases are characterised by incision thereby triggering widespread dsgsds to identify controlling factors and triggering causes and to develop reliable morphoevolutionary models for the dsgsds of western sicily a geomorphological study based on field surveys and aerial photography interpretations was performed previous geomorphological data relating to well known examples of dsgsds were reconsidered leading to remarkable revisions of the interpretative models in certain cases new data were subsequently collected enabling recognition of additional dsgsd phenomena the whole body of data involves a total of 27 dsgsds affecting areas in two specific geological settings 1 areas with flat thrust surfaces where differential settlements back tilting lateral spreads in competent rocks overlying marls and clays large topples and or block type slope movements may develop and 2 areas where deep rooted carbonate units come into lateral contact with clayey marly units along high angle faults where lateral spreads in brittle homogeneous rocks sinking and or rock flows may occur these dsgsd phenomena are associated with different evolutionary stages allowing a morphoevolutionary model to be defined for the two geological conditions for these two different morphoevolutionary models the following structural features play an important role in the development of dsgsds 1 where carbonate bodies overlie clayey marly rocks triggering of the dsgsds traces back to deformation of a ductile substratum that follows the exhumation of the flat thrust planes and the underlying clayey marly rocks due to block faulting and or stream incision and 2 where homogeneous carbonate rocks hundreds of metres thick crop out the dsgsds are triggered by very high relief energy and tensile stress that follow the combined actions of quaternary block faulting and stream deepening associated with differential erosion

climate simulations of the permian triassic boundary ocean acidification and the extinction event 1 the causes for the permian triassic boundary ptb extinction the largest mass extinction on record remain enigmatic the period is marked by large scale volcanic eruptions and evidence for widespread ocean anoxia which have led to suggestions that these events generated or played a part in the extinction furthermore hypercapnia and ocean acidification caused by volcanic emissions of co2 and ch4 have been put forward as potential kill mechanisms we present the first ptb climate simulations in which ocean acidity is evaluated directly with a coupled climate carbon cycle model the experiments also address the sensitivity of ocean circulation and oxygen levels to uncertainties in paleogeography and to different bottom topographies modeled temperature and precipitation evaporation are in good agreement with reconstructions and climate sensitive sediments there is also good agreement between modeled vegetation and reconstructed biomes the reduction in ocean ph brought about by the increase in atmospheric co2 is biologically significant aragonite saturation levels are low enough to make the whole ocean unsuitable to aragonitic species and large areas of the ocean become unsaturated in relationship to calcite no general bottom anoxia is reproduced modeled deep ocean o2 concentrations are not significantly impacted by changes in paleogeography and bathymetry an indication that in our model a change in ocean dynamics resulting from climate warming is not sufficient by itself to generate widespread anoxic conditions during the period

evolution stages of large deep seated landslides at the front of a subalpine meridional chain maritime alps france abstract studying long term evolution of gravitational slope evolution is a key to understanding deep seated landslide processes this paper deals with three large deep seated landslides dsls at a front of a subalpine meridional chain on the la marbriere slope near the town of grasse alpes maritimes france the geological framework controlling the stability and morphology of the dsls is associated with thick and tamped triassic layers of mudstone with gypsum overlain by highly faulted jurassic limestone gravitational deformation affects the entire slope involving a movement of about 1 1 10 8 m 3 of rock material it creates large disturbances in landscape morphology such as scarps counter slope scarps trenches and other typical gravitational morpho structures geomorphological mapping coupled with deep electrical resistivity tomography ert reveals a strong correlation between these morpho structures and inherited brittle tectonic features this observation relies on spatial and geometrical relations on the surface and at the depth of more than 150 m checked by ert between the most persistent fault and the gravitational morpho structures the specific distribution of the morpho structures on the basis of their morphological typologies and variations in the stage of evolution of three dsls provides an interpretation of their kinematics during the last 400 ka it appears that soft substratums combined with inherited persistent anisotropies are key factors in the development of the dsls indeed outflow of mudstone due to the lithostatic pressure imposed by individual limestone compartments has led to general slope subsidence then a progressive toppling of a rock mass may have led to the catastrophic rock collapse along bedding planes the evolution of the dsls can be divided into three distinct stages represented by three zones a young collapse stage zone 1 a pre collapse stage zone 2 and an old mature stage 400 ka zone 3 as the dsls occur on the same slope and in the same geological context this area offers interesting perspectives for understanding factors controlling the long term gravitational evolution of slopes

petrology geochemistry and geochronology of trondhjemites from the qori complex neyriz iran metamorphism magmatism and thrusting were the result of subduction of neotethys beneath the continental margin arc of the sanandaj sirjan shear zone sssz during the mesozoic the qori metamorphic complex is a part of the southern sssz leuco granitic trondhjemitic rocks crop out in the qori metamorphic complex and are rare rock types in the sssz these rocks have intruded into the marbles and garnet amphibolites the highest grade metamorphic rocks of the qori metamorphic complex and in some outcrops a transitional boundary between the amphibolites and the granitoids can be distinguished the granitoids are granular in texture and consist of plagioclase albite oligoclase quartz k feldspar muscovite and subordinate garnet spinel rutile and apatite which primarily occur as inclusions in the main phases the peraluminous trondhjemitic rocks are enriched in na2o and sio2 and depleted in feo mgo and cao similarities with some trondhjemitic liquids produced through partial melting of amphibolites or hydrous basalts i e low al2o3 content less than 15 wt low ba sr tio2 and eu content all with negative anomalies moderately enriched lrees and y and flat hree patterns suggest that the evolution of the parental magma was controlled by residual plagioclases during partial melting of a garnet amphibolite source concentrations of ferromagnesian elements mg fe and mn are low suggesting that the granitic rocks were not produced by high degrees of partial melting furthermore they display low amounts of ferromagnesian components from the protolith garnet amphibolite this is supported by consideration of compatible elements especially cr ni and ti and the less robust hree which respectively show very high and high bulk partition coefficients for relatively small degrees 20 of partial melting of the source the partial melting of the garnet amphibolites occurred at pressures and temperatures between 7 5 and 9 5 kbar at a depth of 25 to 32 km and 680 and 720 degrees c respectively based on the grt hbl and hbl pl thermometers and a grt hbl pl qtz barometer precise u th zircon shrimp ages of the trondhjemite show magmatic ages of 147 4 0 76 ma volgian late jurassic and suggest that neotethys began to subduct beneath the continental margin arc of the sssz as a result of this process an arc related metamorphism occurred leading to the development of the garnet amphibolites in the qori metamorphic complex c 2009 elsevier b v all rights reserved

polyonyx like tracks from middle upper jurassic red beds of morocco implications for sauropod communities on southern margins of tethys abstract a new dinosaur tracksite is reported from continental red beds of the jurassic late bathonian callovian isli formation along the northern flank of the ait ali ou ikkou syncline of the imilchil area central high atlas morocco the succession was deposited in a fluvio lacustrine environment and contains at least fourteen track bearing levels the diverse dinosaur dominated ichnofauna includes the footprints of crocodylomorphs pterosaurs theropods sauropods and ornithischians together with numerous invertebrate traces here we focus on a long sauropod trackway which comprises nine consecutive manus pes sets preserved as concave epireliefs the low heteropody and asymmetry of manus prints with a large digit i pollex impression oriented medially and a large triangular claw trace which is posteriorly oriented are characteristic of the ichnogenus polyonyx different from typical polyonyx is the narrow gauge pattern compared to the wide gauge observed in the type trackway from portugal additional material from morocco similar to polyonyx comprises the trackway of a very small juvenile individual found close to the main trackway as well as a short trackway from a different locality in the isli formation our data from the moroccan high atlas indicates the presence of basal eusauropods in the middle jurassic early cretaceous interval in the northwestern part of gondwana for the first time and suggests they inhabited a lacustrine paleoenvironment

quaternary gravitational morpho genesis of central apennines italy insights from the mt genzana case history abstract this paper focuses on a study aimed at defining the role of geological structural setting and quaternary morpho structural evolution on the onset and development of a deep seated gravitational slope deformation which affects the western slope of mt genzana ridge central apennines italy this case history is particularly significant as it comprises several aspects of such gravitational processes both in general terms and with particular reference to the apennines in fact i the morpho structural setting is representative of widespread conditions in central apennines ii the deforming slope partially evolved in a large rockslide avalanche iii the deformational process provides evidence of an ongoing state of activity iv the rockslide avalanche debris formed a stable natural dam thus implying significant variations in the morphologic hydraulic and hydrogeological setting v the gravitational deformation as well as the rockslide avalanche reveal a strong structural control the main study activities were addressed to define a detailed geological model of the gravity driven process by means of geological structural geomorphological and geomechanical surveys as a result a robust hypothesis about the kinematics of the process was possible with particular reference to the identification of geological structural constraints the process in fact involves a specific section of the slope exactly where a dextral transtensional structure is present thus implying local structural conditions that favor sliding processes the rock mass is intensively jointed by high angle discontinuity sets and the bedding attitude is quite parallel to the slope angle within this frame the gravitational process can be classified as a structurally constrained translational slide locally evolved into a rockslide avalanche the activation of such a deformation can be in its turn related to the quaternary morphological evolution of the area which was affected by a significant topographic stress increase testified by stratigraphic and morphologic evidence

defining the morphological quality of fossil footprints problems and principles of preservation in tetrapod ichnology with examples from the palaeozoic to the present abstract the morphology of fossil footprints is the basis of vertebrate footprint ichnology however the processes acting during and after trace fossil registration which are responsible for the final morphology have never been precisely defined resulting in a dearth of nomenclature therefore we discuss the concepts of ichnotaphonomy ichnostratinomy taphonomy biostratinomy registration and diagenesis and describe the processes acting on footprint morphology in order to evaluate the morphological quality of tetrapod footprints we introduce the concept of morphological preservation which is related to the morphological quality of footprints m preservation acronym mp and distinguish it from physical preservation p preservation acronym pp which characterizes whether or not a track is eliminated by taphonomic and diagenetic processes m preservation includes all the morphological features produced during and after track registration prior to its study and may be divided into substages ichnostratinomic registrational taphonomic stratinomic diagenetic moreover we propose an updated numerical preservation scale for m preservation it ranges from 0 0 worst preservation to 3 0 best preservation intermediate values may be used and specific features may be indicated by letters in vertebrate footprint ichnotaxonomy we regard the anatomy consistent morphology and to a lesser extent the trackway pattern as the only acceptable ichnotaxobases only footprints showing a good morphological preservation grade 2 0 3 0 are useful in ichnotaxonomy whereas ichnotaxa based on poor morphological preservation grade 0 0 1 5 are considered ichnotaphotaxa nomina dubia characterized by extramorphologies we applied the preservation scale on examples from the palaeozoic to the present time including three ichnotaphotaxa and 18 anatomy consistent ichnotaxa morphotypes attributed to several vertebrate footprint producers results indicate the utility feasibility and suitability of this method for the entire vertebrate footprint record in any lithofacies strongly recommending its use in future ichnotaxonomic studies

geophysical and geotechnical studies of geology and sediment properties at a quick clay landslide site at esp trondheim norway abstract increased urbanisation and development in previous marginal areas have led to the need to protect the population the environment and infrastructure from hazards such as quick clay landslides in this paper the opportunity which was presented following the gathering of a large amount of data in the area of the quick clay landslide at esp trondheim norway in 2012 is explored the data is of particular interest given the availability of frequency domain helicopter borne electromagnetic data fhem and extensive lidar imaging as well as a full range of in situ geophysical and geotechnical soundings and samples the ground conditions in the area are shown to be complex and it is clear that a multi disciplinary type approach combining geophysical geomorphological and geotechnical investigations is necessary in order to understand the hazards posed by potential quick clay landslides the investigation shows that very good overview mapping of the area can be obtained from fhem and that the data obtained from local electrical resistivity tomography ert and resistivity cone rcptu are consistent with each other and with the fhem data use of ert immediately after the landslide was particularly useful in delineating further risk areas and as an aid for assessment of evacuation of the local population lidar data is particularly useful in understanding the landslide trigger mechanisms the depth of the landslide the form of the run out and the nature of the material in the run out geotechnical data collected in the area is characteristic of that of soft sensitive norwegian marine clays and the various geotechnical and geophysical parameters correlate well with one another and also follow well established patterns the data shows that no single investigative method is available to accurately define quick clay layers but that a number of complimentary in situ and laboratory techniques are necessary for that purpose

integrated sr isotope variations and global environmental changes through the late permian to early late triassic new 87sr 86sr data based on 127 well preserved and well dated conodont samples from south china were measured using a new technique la mc icpms based on single conodont albid crown analysis these reveal a spectacular climb in seawater 87sr 86sr ratios during the early triassic that was the most rapid of the phanerozoic the rapid increase began in bed 25 of the meishan section gssp of the permian triassic boundary ptb and coincided closely with the latest permian extinction modeling results indicate that the accelerated rise of 87sr 86sr ratios can be ascribed to a rapid increase 2 8 of riverine flux of sr caused by intensified weathering this phenomenon could in turn be related to an intensification of warming driven runoff and vegetation die off continued rise of 87sr 86sr ratios in the early triassic indicates that continental weathering rates were enhanced 1 9 times compared to those of the late permian continental weathering rates began to decline in the middle late spathian which may have played a role in the decrease of oceanic anoxia and recovery of marine benthos the 87sr 86sr values decline gradually into the middle triassic to an equilibrium values around 1 2 times those of the late permian level suggesting that vegetation coverage did not attain pre extinction levels thereby allowing higher runoff

early permian pangea b to late permian pangea a the pre drift wegenerian model of pangea is almost universally accepted but debate exists on its pre jurassic configuration since tedirving introd ucedpangea b by placing gond wana farther to the east by v3000 km with respect to laurasia on the basis of paleomagnetic data new paleomagnetic data from radiometrically dated early permian volcanic rocks from parts of adria that are tectonically coherent with africa gondwana integrated with published coeval data from gondwana and laurasia again only from igneous rocks fully support a pangea b configuration in the early permian the use of paleomagnetic data strictly from igneous rocks excludes artifacts from sedimentary inclination error as a contributing explanation for pangea b the ultimate option to reject pangea b is to abandon the geocentric axial dipole hypothesis by introducing a significant non dipole zonal octupole component in the late paleozoic time averaged geomagnetic field we demonstrate however by using a dataset consisting entirely of paleomagnetic directions with low inclinations from sampling sites confined to one hemisphere from gondwana as well as laurasia that the effects of a zonal octupole field contribution would not explain away the paleomagnetic evidence for pangea b in the early permian we therefore regard the paleomagnetic evidence for an early permian pangea b as robust the transformation from pangea b to pangea a took place during the permian because late permian paleomagnetic data allow a pangea a configuration we therefore review geological evidence from the literature in support of an intra pangea dextral megashear system the transformation occurred after the cooling of the variscan mega suture andlasted v20 myr in this interval the neotethys ocean opened between india arabia and the cimmerian microcontinents in the east while widespread lithospheric wrenching and magmatism took place in the west around the adriatic promontory the general distribution of plate boundaries and resulting driving forces are qualitatively consistent with a right lateral shear couple between gondwana and laurasia during the permian transcurrent plate boundaries associated with the pangea transformation reactivated variscan shear zones andwere subsequently exploitedby the opening of western neotethyan seaways in the jurassic

tectonic vs gravitational morphostructures in the central eastern alps italy constraints on the recent evolution of the mountain range abstract deep seated gravitational slope deformations dsgsds influence landscape development in tectonically active mountain ranges nevertheless the relationships among tectonics dsgsds and topography are poorly known in this paper the distribution of dsgsds and their relationships with tectonic structures and active processes surface processes and topography were investigated at different scales over 100 dsgsds were mapped in a 5000 km2 sector of the central eastern alps between the valtellina engadine and venosta valleys detailed lineament mapping was carried out by photo interpretation in a smaller area about 750 km2 including the upper valtellina and val venosta fault populations were also analysed in the field and their mechanisms unravelled allowing to identify different structural stages the youngest being consistent with the regional pattern of the ongoing crustal deformation finally four dsgsd examples have been investigated in detail by geological and 2d geomechanical modelling dsgsds affect more than 10 of the study area and mainly cluster in areas where anisotropic fractured rock mass and high local relief occur their onset and development is subjected to a strong passive control by mesoscopic and major tectonic features including regional nappe boundaries as well as nw se n s and ne sw trending recent brittle structures the kinematic consistency between these structures and the pattern of seismicity suggests that active tectonics may force dsgsds although field evidence and numerical models indicate slope debuttressing related to deglaciation as a primary triggering mechanism

a large scale lateral spreading its genesis and quaternary evolution in the coastal sector between cogoleto and varazze liguria italy abstract the results of a study carried out on a coastal area of central western liguria northern italy where metamorphosed basic and ultrabasic rocks outcrop are presented the study indicates that a wide area 16 km 2 was involved in a large scale deep seated gravitational slope deformation dsgsd this movement has special features related to the lithology and structure of the involved rock mass to the plio quaternary uplifting and brittle tectonics affecting an area where a paleosurface was recognised and to the continental shelf dynamics the particular geometry of the dsgsd was recognised on the basis of detailed analyses of the above mentioned aspects due to its characteristics the deep seated deformation can be classified as a lateral spreading the current altitude of the pliocene marine clay outcrops and their deposition bathymetry allowed estimation of the uplift rate of the coastal area the altitudinal variations of an ancient marine terrace which was displaced by the dsgsd were used to reconstruct the chronology of the gravitational movement a final issue concerns the very large scale and the particular kind of phenomenon both of which are certainly new in liguria

last glacial to holocene vegetation succession recorded in polyphase slope failure deposits on the malenik ridge outer western carpathians abstract structural settings and palaeoenvironmental reconstruction of a polyphase late pleistocene deep seated landslide at the malenik ridge in the eastern part of the czech republic are presented the deep seated rotational landslide is about 480 m long and 1540 m wide and it is a part of much larger landslide complex the depositional record of two generations of former near scarp depressions revealed a multiple deep seated landslide activity during the last quaternary climatic cycle with the minimum age of 47704 2346 cal b2k the landslide belongs among the oldest dated landslides in the outer western carpathians and carpathian foredeep in the czech republic the younger reactivation started at 12662 73 cal b2k during younger dryas the palaeobotanical and depositional record from the landslide brought unique palaeoenvironmental data for two time intervals of the last quaternary climatic cycle the reconstructed mis 3 forest vegetation with the predominance of stone pine larch pinus cembra larix taiga with pinus sylvestris and betula pendula pubescens are the first evidences of the forest vegetation for the gs13 to gi12 transition in outer western carpathians similarly documented events of mis 3 landslide activity from outer western carpathians are rather rare the late glacial to holocene record from the younger near scarp depression revealed vegetation and landscape changes during the pleistocene holocene transition the evidenced oldest parts of the landslide at the malenik ridge had to originate during more humid interpleniglacial conditions the geomorphological evidence for landslide activity from this period has almost completely disappeared from the ground surface topography due to intensive periglacial processes operating later during the last glacial maximum and subsequent fluvial and anthropogenic processes of the holocene the cold and relatively dry period of the pleniglacial is considered as a time when deep seated mass movements use to be halted and overprinted by shallow solifluction of the active layer masking former deep seated landslide features