large scale slope remodelling by landslides geomorphic diversity and geological controls kamienne mts central europe abstract the kamienne mts in the sudetes central europe bear widespread evidence of landsliding which mainly occurred at the boundary between carboniferous and permian clastic sedimentary rocks and overlying permian volcanic and sub volcanic rocks 47 individual landslides have been delimited using a combination of lidar derived dem analysis and field mapping they have been characterized through a range of geomorphometric parameters and cluster analysis reveals four major groups in terms of surface expression and consequently likely origin and history spatial analysis confirms distinct association of landslides with the steepest terrain and north to east aspect of slopes but distance from lithological contact emerges as the critical parameter 80 of the total landslide area is located within 200 m of a contact on either side of it joint measurements within head scarps at selected landslides indicate that displacements took place along steeply dipping joints in the volcanic cap but the existence of low angle detachment surfaces in the underlying sedimentary formations is inferred the spatial distribution of slope deformations coupled with apparently different although yet unspecified ages of individual landslides suggests that remodelling of the mountain range by landslides is an ongoing process geomorphic history of the area excludes glacial or fluvial erosion and resultant slope de buttressing as the cause of instability rather landslides are considered as mechanisms by which slopes which have become too high and steep due to long term differential erosion restore their strength equilibrium

reconstructing recent landslide activity in relation to rainfall in the llobregat river basin eastern pyrenees spain abstract a chronology of recent landslides in the upper basin of the llobregat river eastern pyrenees has been reconstructed from technical reports field reconnaissance and dendrogeomorphological analysis the precipitation conditions responsible for triggering and reactivating landslides have been deduced by analysis of rainfall records from two rain gauges located in the area two different rainfall patterns relate to landslide occurrence i without antecedent rainfall high intensity and short duration rains trigger mostly debris flows and shallow slides developed in colluvium and weathered rocks a rainfall threshold of around 190 mm in 24 h initiates failures whereas more than 300 mm in 24 48 h are needed to cause widespread shallow landsliding ii with antecedent rain moderate intensity precipitation of at least 40 mm in 24 h reactivates mudslides and both rotational and translational slides affecting clayey and silty clayey formations in this case several weeks and 200 mm of precipitation are needed to cause landslide reactivation dendrochronological analysis shows that landslide activity in the eastern pyrenees was relatively low between 1926 and 1959 but has since increased significantly with reactivation now occurring about every 3 years

the dating of bedrock landslide reactivations using dendrogeomorphic techniques the mazak landslide outer western carpathians czech republic landslides predisposed by the anisotropy of flysch bedrock are typical features of mass movements affecting the outer western carpathians a dendrogeomorphic investigation involving an extensive dendrometric n 1680 survey and tree ring analysis of 176 norway spruce trees picea abies l karst was used to reconstruct the spatial and temporal activity of the mazak landslide situated in the highest part of the czech outer western carpathians as revealed by geomorphic analysis and electrical resistivity tomography the landslide is a translational medium depth 30 m bedrock feature originating at the intersection of inclined bedding planes with diagonal nw nnw striking and longitudinal ne striking sets of joints and faults a tree ring analysis shows nine major landslide years 1929 1940 1949 1960 1972 1980 1985 1997 2000 accompanied by six additional years with minor reactivations 1933 1945 1955 1958 1977 1996 during the past hundred years 1912 2011

reconstruction of landslide movements by inversion of 4 d electrical resistivity tomography monitoring data reliable tomographic inversion of geoelectrical monitoring data from unstable slopes relies critically on knowing the electrode positions which may move over time we develop and present an innovative inverse method to recover movements in both surface directions from geoelectrical measurements made on a grid of monitoring electrodes for the first time we demonstrate this method using field data from an active landslide to recover sequences of movement over timescales of days to years comparison with gps measurements demonstrated an accuracy of within 10 of the electrode spacing sufficient to correct the majority of artefacts that would occur in subsequent image reconstructions if incorrect positions are used over short timescales where the corresponding subsurface resistivity changes were smaller the constraints could be relaxed and an order of magnitude better accuracy was achievable this enabled the onset and acceleration of landslide activity to be detected with a temporal resolution of a few days

gravitationally induced non karst caves tectonic and morphological constrains classification and dating polish flysch carpathians case study abstract analysis of non karst caves in the flysch carpathians confirms the connection between the tectonic evolution of this orogen and the initial phase of cave formation the compressional extensional regime during the tectonic stages of the evolution of the carpathians is the foundation of subsequent gravitational stresses within the slopes which brought about various deformations of rock massifs producing diverse types of subsurface cavities caves therefore most caves that occur in the carpathians represent forms of the opening and widening of joints and stress zones originated much earlier classification based on the chronology and mechanisms of these caves is proposed a chronological approach requires understanding the relationship of cave development to the stages of slope evolution and enables the construction of the morphogenetic classification whereas consideration of the processes affecting the rock massif structure allows geomechanic classification using the morphogenetic criterion three categories of caves can be distinguished initial caves developed during slope deformations preceding the principal slope failures landslides subsequent caves formed during the main slope failure and intermediate caves related to the main scarp formation on the basis of the geomechanic criterion the following types of caves can be distinguished dilational caves formed due to tensional fractures widening dilatancy caves formed due to the fissure macrodilatancy and boulder caves which represent chaotic cavities in order to illustrate this classification type localities of the various cave types are presented the radiocarbon dating of secondary formations speleothems occurring in the caves indicate that they initially formed in the weichselian upper plenivistulian late glacial and early holocene and underwent various transformations

geochemical modeling of the zoned footwall alteration pipe hellyer volcanic hosted massive sulfide deposit western tasmania australia the mineralogy of hydrothermal alteration assemblages siliceous core chlorite zone sericite zone in the footwall pipe of the hellyer volcanic hosted massive sulfide vhms deposit is controlled mainly by the temperature ph and redox state of the hydrothermal fluids based on the results of our numerical modeling the zoned alteration system could have formed by a combination of water rock interaction and cooling with a siliceous core predicted to form at the center of the conduit passing outward to a chlorite dominated zone a sericite rich zone and finally grading out to unaltered andesite these mineralogical changes relate to a gradual evolution of fluid chemistry water rock ratio ph and temperature from the core to the margin of the system initial temperatures were probably close to 350 degrees c and the hydrothermal fluids were reduced h2s dominated at low temperatures 200 degrees c a peripheral alteration zone consisting mostly of k feldspar chlorite sericite and hematite is predicted to form this low temperature zone has not been recognized at hellyer but elevated k2o contents and local k feldspar development have been noted at other vhms deposits suggesting that this zone might form at low temperatures and low water rock ratios in the footwall of vhms deposits if the existence of barren outer k feldspar alteration zones is confirmed the findings could have important implications for exploration specifically with regards to distinguishing ore related alteration zones from barren alteration systems

the influence of dikes on auriferous shear zone development within granitoid intrusions the bourlamaque pluton val d or district abitibi greenstone belt shear zone related gold quartz veins in granitoid intrusions are commonly intimately associated with mafic dikes which may have a profound influence on the localization orientation and kinematics of auriferous shear zones the bourlamaque pluton of the val d or district contains several economic auriferous shear zones most of which follow and overprint diorite dikes mineralization in all deposits consists of quartz tourmaline pyrite veins in reverse oblique orientation with a significant range of strike dip and slip direction the geometry and kinematics of shear zone and vein array within the pluton is more complex than the simple conjugate pattern predicted for a deforming homogeneous intrusion the stress tensor determined from the auriferous shear zones within the pluton indicates the same northerly directed compression recorded by similar shear zones outside the pluton this indicates that the complex shear zone and vein pattern within the pluton reflects the influence of diorite dikes which

postmineralization faults in the beaufor gold deposit abitibi greenstone belt canada geometry origin and tectonic implications for the val d or mining district the beaufor mine is a mesothermal vein type gold deposit hosted by the bourlamaque pluton a synvolcanic intrusion crosscutting archean volcanic rocks of the abitibi greenstone belt in the val d or mining district the auriferous system is related to south dipping reverse shear zones and consists of up to 2 m wide sheared and extensional sulfide rich quartz veins the auriferous veins system is crosscut by two generations of faults east west trending south dipping 60 brittle ductile reverse faults e g the dike 01 central fault system and subvertical to steeply north dipping brittle faults e g the beaufor fault system the dike 01 central fault system presents structural fabrics kinematic and hydrothermal characteristics similar to those of auriferous shear zones both are interpreted as master faults and secondary structures respectively with the dike 01 central fault system acting as a channelway for the updip draining of ore fluids that were mainly trapped in low angle synthetic shear zones incremental deformation and progressive decrease of bulk fluid pressure led to strain localization and faulting of auriferous quartz veins by the dike 01 central fault system the beaufor fault system crosscuts all structures of the beaufor deposit it consists of a series of oblique reverse dextral faults that lack evidence for pervasive hydrothermal alteration the main structure of that system is the east west trending north dipping beaufor fault which is associated with northeast southwest trending synthetic i e west shear faults and north south trending antithetic faults i e post ore faults fault zones of the beaufor mine are reminiscent of large scale tectonics in the val d or mining camp auriferous quartz tourmaline vein deposits are commonly associated with east west trending high angle reverse shear zones and hydrothermal events coeval with or slightly postdating peak metamorphism and regional deformation several fault zones of the val d or area preserve evidence for both reverse shearing and dextral strike slip faulting structures recorded in the beaufor mine suggest that reverse and dextral trancurrent faulting is genetically unrelated and probably resulted from sequential faulting rather than transpression

volcanology and sedimentology of the host succession to the hellyer and que river volcanic hosted massive sulfide deposits northwestern tasmania the hellyer and que river high grade polymetallic volcanic hosted massive sulfide deposits of western tasmania are hosted by a sequence of late middle cambrian subaqueous mafic to felsic volcanics and volcaniclastics known as the que hellyer volcanics these volcanics occur toward the top of a thicker sequence of mainly felsic volcanics also hosting mineralization known as the mount read volcanics the base of the footwall sequence within the que hellyer volcanics is marked by massive to pillowed basaltic lavas and volcaniclastics of variable thickness these are conformably overlain by a thick sequence of andesitic basaltic and minor dacitic lavas and associated volcaniclastics eruption of these footwall sequences was rapid with breaks in volcanism represented only by thin discontinuous epiclastic horizons a hiatus in volcanism followed the emplacement of the footwall sequences this hiatus is represented by the deposition of locally derived coarse grained mass flows the distribution and geometry of these epiclastics suggest that they accumulated in local syndepositional depressions sedimentation was also accompanied by syngenetic zn pb cu ag au rich mineralization in the central or axial area of these depressions rapid burial by further mass flows assisted in the preservation of mineralization shallow intrusive to extrusive dacitic lava flows and domes in the host horizon were emplaced during and immediately after mineralization autoelastic material from these dacitic domes was then resedimented and incorporated in the epiclastic horizons overlying the orebodies eruption of massive to pillowed basaltic and minor andesitic lavas of the hellyer basalt occurred soon after mineralization and was the final phase of volcanism in the que hellyer volcanics the basalts were emplaced as extrusions and as shallow intrusions into wet fine grained sediments which began to accumulate above the coarse grained epiclastic horizons these basalts buried the remaining parts of the sulfide mound not covered by epiclastics immediately after the cessation of volcanic activity in the area a 100 m thick sequence of black shales and minor sandstones known as the que river shale was deposited the general lack of products of explosive volcanism within the que hellyer volcanics is most likely a function of the composition of the lavas combined with their emplacement in deep water under high confining pressures although the absence of such products does not rule out the possibility of emplacement in shallow water depths the absence of abundant large scale tractional sedimentary structures the presence of the overlying black anoxic que river shale and the mass flow characteristics of elastic units favor a relatively deep water setting for mineralization in the que hellyer volcanics

the coulon deposit quantifying alteration in volcanogenic massive sulphide systems modified by amphibolite facies metamorphism the coulon deposit is a volcanogenic massive sulphide vms system in the james bay area superior craton quebec that was metamorphosed to amphibolite facies conditions the chemistry and mineralogy of the vms related alteration halo proximal to the mineralized sulphide lenses are investigated using samples collected in the field and 5583 chemical analyses provided by osisko ltd alteration is quantified using mass balance and normative calculations and the application and performance of these methods in an exploration context are investigated in vms systems altered rocks proximal to the ore zones are characterized by multi element metasomatism which is best quantified by mass balance methods that have been successfully applied in the study area however mass balance calculations necessitate the documentation of a precursor which is not always possible in an exploration context therefore an alternative method i e alteration indices was also evaluated in most vms systems proximal alteratio

airborne and ground based data sources for characterizing the morpho structure of a coastal landslide abstract landslide analysis is increasingly based on the combination of multiple information sources at different spatial and temporal resolutions spatial coverage accuracy and acquired using various airborne and terrestrial platforms and geomorphological geophysical and geotechnical methods morphological mapping and morpho structure characterization are preliminary steps to analyze the observed and future landslide distributions the objective of this work is to propose a morpho structural model of an active landslide complex on the normandy coast north west france by combining different data sources the methodology associates field investigation with interpretation of high resolution topographic and geophysical images the proposed morpho structural model highlights the division of the landslide into several morphological features this division may explain the spatial variability and temporal variability of the slope dynamics

thermal history of the southwestern meguma zone nova scotia from an 40ar 39ar and fission track dating study of intrusive rocks two geologically distinct regions within the meguma terrane have been studied in detail and are shown to have contrasting thermal histories this conclusion is based on 31 new 40ar 39ar age spectra on micas k feldspars and hornblendes from several of the plutons in southern nova scotia which are satellites to the much larger south mountain batholith smb in addition we report four k feldspar age spectra from a locality in the northeastern part of the smb and seven fission track ages from both the southern and northern areas the complex age spectrum of hornblende from a mafic phase associated with the bamngton passage pluton suggests a minimum intrusive age of 385 ma a result consistent with geologic evidence that this pluton represents an early less evolved magmatic pulse later intrusive activity appears to have been coeval with the intrusion of the smb at ca 370 ma ago in the southern region argon clocks in feldspars were completely reset and mica clocks variably reset by a later thermal event the cumulative geochronologic and geologic evidence constrains this event to 300 320 ma ago in the smb this alleghanianl hercynian thermal disturbance is much less pronounced and appears to be localized to small areas that are often associated with economic mineralization k feldspars from the southern plutons record an episode of argon loss 220 230 ma ago which is less evident in the smb to the north upper triassic dike injection in the southern region associated with the initial rifting phase of the canadian atlantic margin accompanied this milder thermal pulse apatites in the two regions record a mean fission track age of ca 180 ma which we attribute to the final cooling of the terrane below about 100 c the timing of this event coincides with regional uplift recorded in sedimentary sequences along much of the maritime continental shelf deux kgions gtologiques distinctes inttgkes au terrane de meguma ont ctt ctudites en dctai1 et leurs histoires thermales

the touquoy zone deposit an example of unusual orogenic gold mineralisation in the meguma terrane nova scotia canada the touquoy zone deposit is host to disseminated gold mineralisation in metasiltstones of lower palaeozoic age from the close correlation between ore grades and the intersection of favourable stratigraphy and bounding faults it is apparent that mineralisation is controlled by both structural and lithological influences within the ore zone disseminated gold arsenopyrite pyrite and rare base metal sulphides are associated with a network of widely spaced millimetre scale quartz carbonate veinlets quasi pervasive fluid flow and prolonged interaction with the host rocks resulted in a diffuse but pronounced halo of wall rock alteration that is characterized by the breakdown of detrital feldspar and metamorphic chlorite and the development of hydrothermal carbonate phases k mica and disseminated sulphides these mineralogical changes are accompanied by enrichment in co2 k au as and s and depletion in na across the ore zone vein formation occurred at between 250 and 350 c and pressures of less than 1 2 kbar 1 kbar 100 mpa corresponding to an estimated depth of between 2 8 and 6 km mineralisation resulted from the unmixing of an overpressured low salinity co2 rich fluid in response to decreasing pressure during its ascent and penetration into permeable host rocks geological and geochemical features of mineralisation in the touquoy zone deposit are seen as convincing evidence for a close genetic association between disseminated style and lode gold mineralisation in orogenic terrains with the resulting style of mineralisation largely controlled by the overall structural geometry of the mineralising site rheological properties permeability and chemical receptiveness of the host rock and structural level of emplacement

a fractal measure of mass transfer in fluid rock interaction abstract exploring the mechanism of mass transfer is critical for characterizing geochemical behaviour of elements in fluid rock interaction and is useful for understanding the sequence of hydrothermal alteration the focus of this study is on identifying the spatial relationship between the concentration variation of elements and the distance of samples to the source of the hydrothermal fluid a mobility index mi was applied to represent the mass changes a value of mi 1 indicates gain of elements x from alteration to the source of hydrothermal fluids is observed for the enriched and depleted elements the relation can be expressed as mi cx d and mi cx d respectively where c is a constant and d is the fractal dimension such relations indicate a power law decrease increase of mi with the decreasing degree of alteration the fractal dimension provides an objective measure of the mass gain or loss the larger the fractal dimension the larger the mass change the fractal dimension sequence quantitatively reveals the activity of ore forming elements and the degree of mass changes in the process of hydrothermal fluid rock interaction which can provide critical information on hydrothermal alteration

hydrological response of weathered clay shale slopes water infiltration monitoring with time lapse electrical resistivity tomography this work presents an attempt to monitor water infiltration and subsurface flow within a clay shale landslide using time lapse electrical resistivity tomography ert a rainfall experiment was carried out on a plot of 100 m2 at the laval landslide in the draix experimental catchments ore draix south french alps in order to characterize the spatial and temporal development of water circulation in the soil and to identify when steady state flow conditions are reached the experiment was conducted during 67 h with initial unsaturated conditions in the slope the apparent electrical resistivity values were inverted with a time lapse approach using several cross models the results indicate a significant decrease in resistivity 18 compared to the initial state in the rain plot downslope progression of negative resistivity anomalies is imaged suggesting that vertical and subsurface lateral flows have developed about 21 h after the start of the rain experiment a constant level of resistivity values is observed indicating that the hydrological system reached steady state flow conditions this observation is consistent with ground water level observations and chemical tracer analysis computed differences in time of steady state conditions highlight possible preferential flows near the landslide toe a hydrological concept of functioning of the slope is proposed and apparent saturated hydraulic conductivity ks of 1 7 10 4 m s 1 is computed from the steady state times this study demonstrates the potentiality of ert monitoring to monitor water infiltration in clay shale slopes and the high water transfer capacity of reworked clay shale material

digital photogrammetric analysis and electrical resistivity tomography for investigating the picerno landslide basilicata region southern italy abstract digital photogrammetric analysis and electrical resistivity tomography ert techniques were applied to evaluate the volume of material involved in a complex roto translational slide occurred in the territory of picerno basilicata region southern italy analytical and digital photogrammetric techniques facilitated a multi temporal analysis of aerial photos for the years 1997 2004 and 2006 in order to identify different geomorphologic features scarps terraces and trenches of the landslide and their development the analytical and digital photo interpretation was performed at the maximum scale of 1 5000 geological and geomorphological surveys were carried out to verify photo interpretation results digital elevation models dems for 1997 2004 and 2006 were produced by applying the grid adaptive method the differential dems 2006 1997 2006 2004 2004 1997 for the most dangerous part of the landslide allowed us to recognize the areas affected either by deposition or erosion and also estimate any altitudinal changes in each geomorphologic unit to detect the sliding surface and estimate the thickness of the sliding material several transversal and longitudinal ert profiles were obtained the electrical images of subsurface supported by stratigraphical data from boreholes were integrated with the information from the dems the altitudinal changes and the sizes of the source and accumulation areas allowed us to estimate the volume of material involved in the mass movement the fusion of data from different sensors allows us to gather indications on the surface and subsurface characteristics of the landslide providing useful information for landslide mitigation activities such an approach can help both to improve our knowledge and overcome the drawbacks of each methodology

a combined geomorphological and geophysical approach to characterising relict landslide hazard on the jurassic escarpments of great britain abstract the jurassic escarpment in the north york moors in northern britain has a high density of deep seated relict landslides but their regional hazard is poorly understood due to a lack of detailed case studies investigation of a typical relict landslide at great fryup dale suggests that the crop of the whitby mudstone formation is highly susceptible to landslide hazards the mudstone lithologies along the escarpment form large multiple rotational failures which break down at an accelerated rate during wetter climates and degrade into extensive frontal mudflows geomorphological mapping high resolution lidar imagery boreholes and geophysical ert surveys are deployed in a combined approach to delimit internal architecture of the landslide cross sections developed from these data indicate that the main movement displaced a bedrock volume of c 1 107 m3 with a maximum depth of rupture of c 50 m the mode of failure is strongly controlled by lithology bedding joint pattern and rate of lateral unloading dating of buried peats using the ams method suggests that the 10 m thick frontal mudflow complex was last active in the late holocene after c 2270 30 calendar years bp geomorphic mapping and dating work indicates that the landslide is dormant but slope stability modelling suggests that the slope is less stable than previously assumed implying that this and other similar landslides in britain may become more susceptible to reactivation or extension during future wetter climatic phases this study shows the value of a multi technique approach for landslide hazard assessment and to enhance national landslide inventories

electrical resistivity imaging for the characterization of the montaguto landslide southern italy abstract electrical resistivity tomography surveys were carried out for the characterization of the montaguto earth flow located in the southern apennines chain campania region southern italy the earth flow investigated is one of the largest and most complex landslides in europe with a length of 3 1 103 m a width ranging between 45 and 420 m and an area of about 6 6 105 m2 in the spring of 2010 a large reactivation of the earth flow heavily damaged some strategic infrastructures in order to mitigate the effects of the mass movement considerable efforts were carried out by the italian national civil protection department dpc to tackle the emergency the aim of the study was to contribute to a more accurate geometric reconstruction of the landslide body and to improve the knowledge of the geological setting due to the lithological characteristic of the outcropping lithotypes i e faeto flysch calcarenite clay and marl and villamaina unit sand and silty clay the electrical resistivity contrasts were not very pronounced however the high resolution of the electrical tomographies was the key to observe the presence of both lateral and vertical discontinuities that were associated with lithological boundaries structural features and sliding surfaces the results of the geoelectrical surveys could be considered for planning additional and more appropriate actions aimed at the stabilization of different portions of the montaguto landslide

australian volcanic hosted massive sulfide deposits features styles and genetic models the cambro ordovician period has yielded the major development of volcanic hosted massive sulfide vhms deposits in australia resulting in about 12 million metric tons of contained metal copper lead and zinc concentrated in the mount read volcanics tasmania and the mount windsor volcanics queensland the archean 4 million metric tons of metal and the silurian 3 5 million metric tons of metal constitute the next important episodes while the devonian and permian have produced isolated deposits the deposits range from cu type to zn cu type to zn pb cu type the zn cu type deposits are restricted to the archean and silurian whereas the cu type and zn pb cu type occur sporadically throughout the time span from early archean to permian in general terms the major vhms bearing districts are calc alkaline in character and display a thick basal pile of rhyolitic volcanics 1 3 km thick including lavas epiclastics and subvolcanic intrusions which is overlain by a polymodal sequence containing various proportions of rhyolite dacite andesite basalt and sediments the major deposits are commonly located at the top contact of the rhyolite pile or within the lower part of the overlying polymodal sequence there is a wide range in variability of styles of australian vhms deposits including mounds pipes sheets layered deposits stacked deposits stockwork and disseminated deposits distal reworked deposits and cyclic layered deposits although these various styles show a range of features there is a consistent theme across the spectrum of metal zonation alteration mineralogy alteration chemistry sulfur isotopes macrotextures microtextures and host volcanic relationships which strongly suggests that they all belong to the one genetic group of ore deposit the classic mound style deposits such as hellyer have a series of key features subsets of which are represented in the other deposit styles the mound deposits are considered to form from deposition of metal sulfides on the sea floor immediately around the hydrothermal vent growth of the mound occurs by upward replacement of sulfide assemblages stable at higher fluid temperatures leading to zone refining and lead zinc silver gold enrichment in the outer and upper parts of the mound departure from the classic mound style of deposit is related principally to three key factors the chemistry of the ore fluid salinity temperature f02 and ah2s the nature permeability and chemistry of the volcanic pile and the sea hoor environment sea hoor topography and seawater depth these factors control the aspect ratio of the deposit the extent of stringer zone development the degree of subsea floor replacement mineralization the nature and spatial development of footwall alteration and the development and style of related distal mineralization sulfur isotope studies of australian vhms deposits indicate that reduced seawater sulfate is a major source of sulfur in the deposit whereas lead and strontium isotope results are compatible with the metals being derived by seawater convection and leaching from the volcanic pile and basement rocks this conclusion is supported by the application of various leaching models which demonstrate the availability of an adequate source of both base and precious metals in the footwall volcanic sequences the input of metals directly from volcanic magma chambers is not precluded by the available data and one likely scenario involves the contribution of gold and copper from a magmatic vapor plume rising to mix with convective seawater fluids which contribute lead zinc silver and gold leached from the footwall volcanics and basement rocks the relative importance of the magmatic input compared with the seawater convective input may help to explain the spectrum of deposit styles arid their spatial relationship to volcanic centers or adjacent sedimentary basins

consonorm_lg new normative minerals and alteration indexes for low grade metamorphic rocks the consonorm lg method provides a standardized solution for approximating metamorphic parageneses as well as indexes for estimating chemical and mineralogical changes caused by hydrothermal alteration consonorm lg is designed for rocks dominated by silicates fe ti oxides and or carbonates and it approximates the main parageneses of greenschist and lower amphibolite grade metamorphic rocks for three sets of temperature and pressure conditions 350 c and 2 5 kbars 450 c and 2 5 kbars 575 c and 2 kbars for each model the norm calculates the main paragenesis using an acfmnk tetrahedron a convenient way of representing a large number of silicate assemblages in addition to silicate minerals consonorm lg calculates fe ti oxides and other accessory minerals from minor elements as well as sulfides from analyzed s or from analyzed metals and carbonates from analyzed co2 or from normative co2 estimated from loss on ignition loi consonorm lg also calculates several alteration indexes to estimate fe mg e g chloritization ca e g propylitic alteration na and k acid alterations e g sericitization phyllic alterations and al gain e g argillization carbonatation indexes are also calculated using the amount of normative minerals formed by this type of alteration i e carbonates chlorite and muscovite the normative calculation is validated using published whole rock analyses and petrographic descriptions alteration indexes are validated using several natural samples of alteration halos around base metal and gold deposits

rapid least squares inversion of apparent resistivity pseudosections by a quasi newton method1 a fast inversion technique for the interpretation of data from resistivity tomography surveys has been developed for operation on a microcomputer this technique is based on the smoothness constrained least squares method and it produces a two dimensional subsurface model from the apparent resistivity pseudosection in the first iteration a homogeneous earth model is used as the starting model for which the apparent resistivity partial derivative values can be calculated analytically for subsequent iterations a quasi newton method is used to estimate the partial derivatives which reduces the computer time and memory space required by about eight and twelve times respectively compared to the conventional least squares method tests with a variety of computer models and data from field surveys show that this technique is insensitive to random noise and converges rapidly this technique takes about one minute to invert a single data set on an 80486dx microcomputer

new tectonic divisions of the grenville province southeast canadian shield on the basis of geological geophysical and geochronological data the grenville province has been divided into three first order longitudinal belts the parautochthonous belt pb allochthonous polycyclic belt apb and allochthonous monocyclic belt amb these are set apart by three first order tectonic boundaries the grenville front gf allochthon boundary thrust abt and monocyclic belt boundary zone mbbz the belts are subdivided into terranes based on internal lithological character the gf separates the archean to proterozoic foreland northwest of the orogen from reworked equivalents to the southeast continuous at the scale of the orogen its main characteristic is that of a crustal scale contraction fault the pb although less clearly identified along the length of the orogen in most places represents upgraded and tectonically reworked rocks of the adjacent foreland the boundary between the pb and the apb to the southeast the abt is most clearly delineated in the eastern half of the province it is the locus of major crustal delamination along which high grade mostly middle proterozoic polycyclic terranes were tectonically transported northwest toward and onto the pb the amb comprises two separate areas underlain by the wakeham supergroup and what is currently known as the grenville supergroup respectively its basal contact the mbbz is a decollement zone of variable kinematic significance between older polycyclic rocks and tectonically overlying monocyclic rocks this first order zonation implies a tectonic polarity to the grenville province superimposed on which are second order features evident from contrasting tectonic styles and radiometric ages these characteristics are consistent with a diachronous or oblique collisional model for the grenville orogen

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

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

jointly reconstructing ground motion and resistivity for ert based slope stability monitoring author s boyle a wilkinson pb chambers je meldrum pi uhlemann s adler a abstract the authors 2017 published by oxford university press on behalf of the royal astronomical society electrical resistivity tomography ert is increasingly being used to investigate unstable slopes and monitor the hydrogeological processes within but movement of electrodes or incorrect placement of electrodes with respect to an assumed model can introduce significant resistivity artefacts into the reconstruction in this work we demonstrate a joint resistivity and electrode movement reconstruction algorithm within an iterative gauss newton framework we apply this to ert monitoring data from an active slow moving landslide in the uk results show fewer resistivity artefacts and suggest that electrode movement and resistivity can be reconstructed at the same time under certain conditions a new 2 5 d formulation for the electrode position jacobian is developed and is shown to give accurate numerical solutions when compared to the adjoint method on 3 d models on large finite element meshes the calculation time of the newly developed approach was also proven to be orders of magnitude faster than the 3 d adjoint method and addressed modelling errors in the 2 d perturbation and adjoint electrode position jacobian

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

geophysical survey to estimate the 3d sliding surface and the 4d evolution of the water pressure on part of a deep seated landslide geophysical surveys were conducted on the very unstable front part of the la clapiere landslide in the french alps alpes maritimes the electrical resistivity survey was carried out to obtain for the first time on this deep seated landslide 3d information on the slipping surface and the vertical drained faults moreover we planned to follow within time 6 months the evolution of the saturated zones presence of gravitational water and their percolation into the shearing zones our 4d results showed the importance of the complex water channelization within the slope and relation to geological discontinuities

hydrothermal alteration zoning and gold concentration at the kerr addison archean lode gold deposit kirkland lake ontario kerr addison a major archcan lode gold deposit of the abitibi belt with a production of approximately 10 x 10 6 oz au approximately 320 metric tons up to 1983 is localized in a zone of talc carbonate and chlorite carbonate rocks immediately south of a regional structural break the kirkland lake larder lake fault zone relict volcanic textures taken in conjunction with the ratios of diag nostic relatively less mobile elements collectively indicate that most of the wall rocks of the mine were originally mafic and ultramafic rocks along with their clastic derivatives regional greenschist facies metamorphism is locally superposed by a distinct zonation of gold associated hydrothermal alteration characterized by massive introduction of co 2 coupled with variable enrichments of alkali metals and calcium which produced systematic trends of alteration mineral assemblages alteration types of the initial stage contain chlorite which is replaced by muscovite or albite in the advanced stage of alteration with a concomitant increase in the proportion of carbonate minerals numerous generations of crosscutting veins are enveloped by alteration borders in which the sequence of the al bearing minerals namely albite mus covite and chlorite develop from the vein to the wall rocks always in a systematic sequence the same sequence is observed at a larger scale from the ore zone to the periphery of the mine area the intensity of alteration can be monitored by saturation indices co 2 ca fe mg for carbonates and 3k na al 3k al and na al for muscovite albite muscovite and albite respectively molar ratios plots of the moving averages of these indices across the 3 850 ft level of the mine reveal a remarkable correspondence to variations of gold abundance suggesting a genetic relationship of gold enrichment to hydrothermal alteration on a broad scale gold is concentrated to the south of the kirkland lake larder lake fault zone and at a more detailed scale in the transition zone between carbonate muscovite and carbonate albite alteration types during advanced alteration fluid x sub co 2 was approximately 0 1 and na k asymp 10 volcanics of the kinojevis and larder lake groups are 18 o enriched relative to pristine tholeiites and possess distinct mineral delta 18 o values probably due to different conditions of marine water alteration during or shortly after extrusion in domains of advanced alteration these are all shifted down to a common narrow bracket here 18 o 16 o and d h data indicate fairly constant temperatures 270 degrees 300 degrees c and a common isotopic composition of hydro thermal fluids delta 18 o 5ppm delta d 30 to 50ppm across the alteration zoning these results are in common with many other archcan lode gold deposits fe dolomite has a uniform delta 13 c value of 2 8 or 0 42 per mil 1sigma throughout the footwall and ore zones but it is enriched by approximately 1 per mil in the graphite free hanging wall rocks fluid delta 13 c value was 4 or 1 per mil reflecting either a magmatic carbon reservoir or mixtures of marine carbonate carbonaceous and magmatic sources the enrichment of gold at one side of the kirkland lake fault zone is interpreted to be the result of development of a metasomatic zoning induced by gradients in oxidation state the precious metal being concentrated in the reducing side zonation of alteration types south of the kirkland lake larder lake fault zone represents various steps of a continuous process of incremental changes of the rocks to adapt to the composition of an externally generated fluid successive generations of fracture arrays and veins have the same alteration patterns and thus the composition of the incoming hydrothermal fluid seems to have remained essentially unchanged through time gold mineralization at the kerr addison mine and its contiguous alteration halo are interpreted to be the result of repeated cycles of hydraulic fracturing fluid penetration and local reaction with rocks fluid rock interaction produced lateral variations of fluid composition which led to gold concentration probably due to gradients in ph preferentially at the interface between the carbonate muscovite and carbonate albite alteration types which is also the site of pyrite concentration the alteration assemblages and specific site of gold pyrite concentration at kerr addison are common to several other described archcan lode gold deposits

kinematic behaviour of a large earthflow defined by surface displacement monitoring dem differencing and ert imaging abstract large earthflow type landslides are destructive mass movement phenomena with highly unpredictable behaviour knowledge of earthflow kinematics is essential for understanding the mechanisms that control its movements the present paper characterises the kinematic behaviour of a large earthflow near the village of ubietova in central slovakia over a period of 35 years following its most recent reactivation in 1977 for this purpose multi temporal spatial data acquired by point based in situ monitoring and optical remote sensing methods have been used quantitative data analyses including strain modelling and dem differencing techniques have enabled us to i calculate the annual landslide movement rates ii detect the trend of surface displacements iii characterise spatial variability of movement rates iv measure changes in the surface topography on a decadal scale and v define areas with distinct kinematic behaviour the results also integrate the qualitative characteristics of surface topography in particular the distribution of surface structures as defined by a high resolution dem and the landslide subsurface structure as revealed by 2d resistivity imaging then the ground surface kinematics of the landslide is evaluated with respect to the specific conditions encountered in the study area including slope morphology landslide subsurface structure and local geological and hydrometeorological conditions finally the broader implications of the presented research are discussed with particular focus on the role that strain related structures play in landslide kinematic behaviour

formation on the sea floor of the hellyer volcanogenic massive sulfide deposit new fluid inclusion data from the stockwork veins beneath the hellyer orebody a relatively undeformed late cambrian polymetallic volcanogenic massive sulfide deposit allow semiquantitative modeling of the behavior of the ore fluids on the sea floor and the manner of growth of the massive sulfide the earliest cool fluids may have been denser than seawater and ponded in a basin identified by sedimentological and structural studies subsequent vent fluids buoyant with respect to the brine pool and subsequently at higher temperature with respect to seawater mixed with the cooler brine during and after filling the basin to the level of its lowest outlet density inhomogeneities within the brine pool were reduced by double diffusive convection across the brine seawater interface and internal boundaries and mixing by currents within the brine pool estimates of likely temperatures and salinities in the brine pool for the first main mineralization stage avg 200 c 11 wt salinity assuming a steady or quasisteady state had been established and using volume fluxes similar to those observed in modern oceans indicate temperatures 100 c sulfides mostly pyrite sphalerite and galena precipitated from the vent fluids after mixing with cooler basin fluid settled from the gravity current to the basin floor a pattern that would have continued whether or not a true steady state was reached if the early fluids were buoyant in seawater they ponded after mixing forming a hybrid brine pool that would have required longer periods to homogenize at the peak temperature 300 c and volume flux the salinity of the vent fluids fell to 7 5 wt percent but the flow paths would have been maintained unless the brine pool had been drained at this time that part of the massive sulfide body over the vent the cu core grew by dilatational veining together with leaching cavity infilling replacement and recrystallization chalcopyrite was deposited both in the cu core and probably at the same time in a layer over the flanking massive sulfide in the final stage as temperature fell and salinity rose avg 250 c 11 wt salinity the fluid oxidation potential increased so that barite precipitation dominated resulting in a formation of a discontinuous barite rich cap over the massive sulfide the brine pool model explains several features of the hellyer ore that differ from those of the ores of the hokuroko basin namely the large metal content high zn cu ratio low aspect ratio absence of chimney fragments presence of mineral banding and high barite sulfur isotope values features seen in many other massive sulfide orebodies

assessment of active landslides using field electrical measurements abstract landslide characterization and hazard assessments require multidisciplinary approaches that connect geologic processes with geotechnical parameters preexisting landslide activity geology and geomorphology soil strength and hydrologic conditions are complex factors that affect landslide behavior often the connections among these factors are not made for hazard assessments forecasting or slope stability modeling therefore geophysical and geotechnical techniques for landslide investigations are typically assessed independently this study aims to bring together different techniques to develop a methodology that connects electrical measurements and shear strength a framework has been developed for using electrical resistivity measurements that will support and facilitate the prediction of shear strength within a slope in situ volumetric water content soil water potential suction and electrical conductivity were measured from two shallow colluvial landslides in kentucky repeated surface electrical resistivity survey measurements were used to characterize the failure zone and lithology and to compare with the in situ hydrologic measurements the data show that subsurface moisture conditions over time can be reflected in the inversions of repeated er surveys thus allowing electrical measurements and geotechnical parameters to be correlated this study demonstrates that electrical resistivity can be used as a tool for landslide monitoring and to assess shear strength these parameters are pertinent to investigating the stability of landslides that are often triggered or reactivated by rainfall

geology and metamorphism of the montauban north gold zone a metamorphosed polymetallic exhalative deposit grenville province quebec the stratiform gold zones and massive sulfide zn pb cu au ag deposit at montauban quebec occur as part of a series of helikian supracrustal rocks metamorphosed to the upper amphibolite facies the mine sequence at the north gold zone consists of nodular sillimanite gneiss cordierite anthophyllite zincian staurolite kyanite gneiss and manganiferous garnet gahnite quartzitic gneiss porphyroblastic gahnite is present only in the gold bearing unit but finer grained gahnite was observed in the remainder of the sequence for up to 20 m on either side gahnite was formed mainly by desulfurization of sphalerite breakdown of zincian staurolite and breakdown of zn bearing biotite peak metamorphic conditions are estimated at t 650 degrees c p 6 kb f sub o 2 10 super 17 bars and f sub s 2 10 super 2 bars mn ranges up to 25 wt percent in garnet and zn up to 8 wt percent in staurolite zn ratios in staurolite correlate closely with those of gahnite r 0 85 and bulk rock r 0 72 zn cu zn pb bulk ratios increase symmetrically away from the ore zone the mine sequence is interpreted as a metamorphosed exhalative system consisting of a siliceous exhalite containing gold and sulfide mineralization and anomalous mn ba and b the other units were initially chlorite sericite quartz hydrothermal alteration assemblages

geochemical and mineralogical diagnosis on gold ores a case study from the cadillac larder lake fault zone abitibi canada abstract numerous orogenic gold deposits have been discovered within the archean abitibi greenstone belt of canada these include the francoeur wasamac astoria zulapa goldex lamaque lac herbin and beaufor deposits all of which are located within the cadillac larder lake fault zone cllfz these gold deposits are hosted by various lithologies and vary in terms of style of mineralization sulfide abundance and hydrothermal alteration these variations mean that exploration for new deposits has been difficult in this area using common exploration criteria this study presents the results of a principal component analysis pca based approach combining geochemical and mineralogical data to quickly identify different types of gold mineralization within the cllfz including assessing the use of this approach in mineral exploration the first principal components in both classification methods used during this study pce1 and pcm1 representing element geochemical and mineralogical classification respectively can efficiently discriminate between mineralization and barren altered rocks the second principal components pce2 and pcm2 can be used to constrain the host rocks altered vs barren and style of mineralization disseminated vs vein hosted respectively finally pce3 and pcm3 give more detailed information on the nature of the mineralization in an area possible reflecting variations in the composition of ore forming fluids all of the above indicates that the two pce and pcm classification methods are complementary which means that using approaches that combine these methods will provide a comprehensive understanding of the nature of studied samples and or deposits information extracted from the results of the pca undertaken during this study may be beneficial for mineral exploration in unknown districts such as glaciated areas where traditional geological fieldwork is challenging this study also defines element and mineral mineralization indices based on pce1 and pcm1 which enables evaluation of the extent and style of gold mineralization in an area this study indicates that pca based automated mineralogical and geochemical classification methods could be highly useful in exploration for gold deposits

impact of mass movements on geo and biodiversity in the polish outer flysch carpathians complex research was simultaneously done on the geological geomorphological and biocenotic features of landslide areas in the polish outer flysch carpathians the research allowed us to define the relations between the diversity of the landslide originating landforms and the biotopes occurring within them high geodiversity diversity of landforms soil and water of landslide areas allows for a mosaic network of extremely diversified natural habitats all of these natural habitats together are characterized by a specific biodiversity dependence between geo and biodiversity in landslide areas is connected with a specific co evolution which is related to the adaptation of the ecosystems to landforms comprehensive research of this relation to landslide areas would promote the necessity to protect the landslide areas unfortunately such research done in the carpathians is still sporadic the comprehensively documented landslide areas are especially valuable elements of the nature protection network within the carpathian euro region if made reasonably accessible they may be used for didactic purposes and in geotourism

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

2d electrical resistivity imaging of some complex landslides in lucanian apennine chain southern italy we use high resolution electrical resistivity imaging to delineate the geometry of complex landslides in the lucanian apennine chain of southern italy to identify the discontinuity between the landslide material and bedrock and to locate possible surfaces of reactivation the lucanian apennine chain is characterized by high hydrogeological hazard and shows a complete panorama of mass movements in this area all typologies of landslides markedly predisposed and tightly controlled by the geostructural characteristics are found rotational and translational slides rototranslational slides earth and mudflows as well as deep seated gravitational slope phenomena with a predominance of rototranslational slides evolving as earthflow slides three test sites characterized by complex geology and a high hydrogeologic hazard are studied the giarrossa and varco izzo earthflow slides are located to the west and east of the town of potenza whereas the latronico slide is located close to the town of latronico

hydrogeochemistry and reservoir model of fuzhou geothermal field china abstract fuzhou geothermal field is a low to intermediate temperature geothermal system consisting of meteoric water that circulates deeply along faults the area of the field is about 9 km2 but it is elongated in a nnw trending direction fluids in the field are controlled by a series of four nnw extensional faults in cretaceous granitic basement fuzhou fault zone these faults feed warm waters into overlying permeable quaternary sediments the hydrothermal system consists of north and south parts whose chemical compositions are subtly different in the northern part the system discharges sulfate chloride waters with relatively low chloride concentrations but in the south the system discharges chloride waters having relatively high chloride concentrations maximum wellhead temperatures are 97 c which agrees with the chalcedony geothermometer in many cases based on the solubility of quartz the deep reservoir temperature cannot exceed 123 to 131 c from heat and mass balance calculations we conclude that the present total extracted capacity of fluid from the reservoir 20 000 tons day could be doubled without noticeable drawdown we estimate the recoverable heat in the reservoir to be about 1 71 1011 mj

rainfall thresholds for possible landslide occurrence in italy abstract the large physiographic variability and the abundance of landslide and rainfall data make italy an ideal site to investigate variations in the rainfall conditions that can result in rainfall induced landslides we used landslide information obtained from multiple sources and rainfall data captured by 2228 rain gauges to build a catalogue of 2309 rainfall events with mostly shallow landslides in italy between january 1996 and february 2014 for each rainfall event with landslides we reconstructed the rainfall history that presumably caused the slope failure and we determined the corresponding rainfall duration d in hours and cumulated event rainfall e in mm adopting a power law threshold model we determined cumulated event rainfall rainfall duration ed thresholds at 5 exceedance probability and their uncertainty we defined a new national threshold for italy and 26 regional thresholds for environmental subdivisions based on topography lithology land use land cover climate and meteorology and we used the thresholds to study the variations of the rainfall conditions that can result in landslides in different environments in italy we found that the national and the environmental thresholds cover a small part of the possible de domain the finding supports the use of empirical rainfall thresholds for landslide forecasting in italy but poses an empirical limitation to the possibility of defining thresholds for small geographical areas we observed differences between some of the thresholds with increasing mean annual precipitation map the thresholds become higher and steeper indicating that more rainfall is needed to trigger landslides where the map is high than where it is low this suggests that the landscape adjusts to the regional meteorological conditions we also observed that the thresholds are higher for stronger rocks and that forested areas require more rainfall than agricultural areas to initiate landslides finally we observed that a 20 exceedance probability national threshold was capable of predicting all the rainfall induced landslides with casualties between 1996 and 2014 and we suggest that this threshold can be used to forecast fatal rainfall induced landslides in italy we expect the method proposed in this work to define and compare the thresholds to have an impact on the definition of new rainfall thresholds for possible landslide occurrence in italy and elsewhere

distribution and failure modes of the landslides in heitai terrace china abstract agricultural irrigation has increased the groundwater level in the heitai terrace part of the heifangtai terrace by 20 m over nearly five decades which causes 3 5 landslides each year at the edge of the terrace the heitai terrace is of great interest in the study of loess related landslides but there is no unanimous agreement on the types of either the landslides in this study site or the loess related slope failures in general on the basis of aerial images res 5 cm digital elevation model res 10 cm and field investigations we analyzed the distribution and failure mode of the landslides in heitai the geological structure and characteristics of 69 landslides vol 5 10 3 6 10 6 m 3 are studied the preliminary results of groundwater recharge in the terrace and formation of the apparent spring lines on the slope surface are analyzed to better understand the failure modes we divided the landslides in heitai into two groups based on the location of the failure surface i e loess landslide and loess bedrock landslide of which the development is governed by the angle between the principle direction of slope deformation and the dip of bedrock bedding we further analyzed the failure mode of each type observed in heitai defined as follows loess bedrock planar slide loess bedrock irregular slide loess flowslide loess slide and loess flow the proposed types of loess related landslide are to be incorporated in the varnes classification varnes 1978 in consideration of the engineering properties of loess and to provide backward compatibility for heitai and potentially other regions in the loess plateau of china

origin of quartzofeldspathic gneisses at montauban les mines quebec quartzofeldspathic gneisses near zinc lead gold mineral deposits at montauban les mines quebec have been examined geochemically to determine whether their protoliths were dominantly sedimentary or igneous the gneisses are generally similar in average compositions to both rhyolitic rocks and sandstones greywackes in particular the most useful methods of protolith discrimination were found to be 1 log sio2 al2o3 versus log cao na2o k2o 2 niggli si versus mg 3 normative quartz 4 shaw s discriminant function application of these criteria indicates that the montauban quartzo feldspathic gneisses were derived dominantly from quartzose sandstone or greywacke protoliths or both

sackung and enigmatic mass movement folds on a structurally controlled mountain ridge abstract the recently emerged concept of slope tectonics suggests that mass movement processes can produce structures similar in morphological expression to that of extensional strike slip and compressional tectonic deformations further there has long been debate about the tectonic or gravitational origin of lineaments found on hillslopes here we present cases of where geological structure and inherited tectonic structures have preconditioned the development of mass movements and creation of slope tectonic features on a monoclinal ridge smrk mt in the outer western carpathians czechia geomorphic mapping from lidar derived topography structural measurements electrical resistivity tomography and ground penetrating radar were used to map synthetic and antithetic scarps thrusts and folds and assess their relation to geological and tectonic structures the scarps are found to be strongly related to transverse nnw to nne trending inherited normal and strike slip faults and mainly cross cut the topography of the mountain ridge some of the folds are thought to have originated from buckling or compression in the distal parts of landslides in other places transpressional folds have developed oblique to major lateral shear surfaces interpreted to be sackung mass movement scarps that have been inherited from tectonic faults the transpressional folds developed due to localized contraction along bends in the lateral shear surface as mass movement proceeded ramp flat thrust folds developed in the compressional parts of landslides where the landslide intersects with slope parallel sackung and or inherited fault planes inclined to the slope altogether this study demonstrates a connection between kinematics of deep seated gravitational slope deformations dsgsds shallower landslides and the origin of transpressive ramp flat thrust and detachment structures in rock slopes