on the structure of grain boundaries in tectonites abstract grain boundaries in several tectonites have been examined using high voltage and scanning transmission electron microscopy on a gross scale grain boundaries are observed to differ from the host crystal in exhibiting faster rates of preferential etching during ion beam thinning and faster rates of ionization damage during exposure to the electron beam grain boundary features can be grouped according to decreasing size as follows grain junction voids that can form linked networks of tubules arrays of isolated voids and inclusions along the grain boundary surface and a narrow grain boundary film of distorted crystal structure the presence of inclusions in voids and the propensity for electron damage along the boundary suggests that the former were initially fluid filled and that the latter may be hydrated initial microchemical analyses using stem indicate that no compositional difference exists between the grain boundaries and host crystals the overall complex grain boundary structure in tectonites suggests that the effective grain boundary width for intercrystalline diffusion is much greater than that proposed based on metals and that diffusion path lengths along grain boundaries are much less than the theoretical maximum the net effect is to greatly enhance deformation mechanisms dependent on intercrystalline mass transport

geochemistry and mineralogy of surface pyritic tailings impoundments at two mining sites of the iberian pyrite belt sw spain two pyritic tailings impoundments located in two mining areas of the iberian pyrite belt cueva de la mora and minas de riotinto zarandas were selected to asses their potential environmental impact mineralogical xrd diffraction study physico chemical characterization colour particle size ph acid base account total fe as cu pb and zn as well as a speciation study by means of a seven step sequential extraction procedure were performed in superficial 0 20 cm tailings samples arsenic and metal contents in soils around the tailings impoundments were also studied zarandas dam a reclaimed impoundment which has been limed partially topsoiled and planted has supported and allowed the growth of pine trees and other plants for many years the surface of this impoundment can be considered very acid but nonacid forming although total as and metal concentrations were relatively high it is not possible to conclude that the zarandas tailings have polluted the surrounding soils tailings in cueva de la mora showed high total and easily mobilizable concentration of toxic elements the net neutralization potential was strongly negative as a consequence of the acid generation caused by the sulphide oxidation the presence of secondary acid generating minerals and the absence of neutralizing materials coquimbite and rhomboclase efflorescences formed during the mediterranean dry summers on the surface of this impoundment contained very high levels of soluble as cu and zn that were easily dissolved and released to the running water in the first rains of autumn

microstructural and crystal fabric evolution during shear zone formation abstract the microstructures and crystal fabrics associated with the development of an amphibolite facies quartzo feldspathic mylonitic shear zone torridon nw scotland have been investigated using sem electron channelling our results illustrate a variety of microstructures and fabrics which attest to a complex shear zone deformation history microstructural variation is particularly pronounced at low shear strains significant intragranular deformation occurs via a domino faulting style process whilst mechanical incompatibilities between individual grains result in characteristic grain boundary deformation accommodation microstructures a sudden reduction in grain size defines the transition to medium shear strains but many of the boundaries inherited from the original and low shear strain regions can still be recognized and define distinctive bands oriented at low angles to the shear zone margin grains within these bands have somewhat steeper preferred dimensional orientations these domains persist into the high shear strain mylonitic region where they are oriented subparallel to the shear zone margin and consist of sub 20 m grains the microstructures suggest that the principal deformation mechanism was intracrystalline plasticity with contributions from grain size reduction via dynamic recrystallization grain boundary migration and grain boundary sliding crystal fabrics measured from the shear zone vary with position depending on the shear strain involved and are consistent with the operation of several crystal slip systems e g prism basal rhomb and acute rhomb planes in a consistent direction probably parallel to a and or m they also reveal the presence of dauphine twinning and suggest that this may be a significant process in quartz deformation a single crystal fabric evolution path linking the shear zone margin fabric with the mylonitic fabric was not observed rather the mylonitic fabric reflects the instantaneous fabric which developed at a particular location for a particular shear strain and original parental grain orientation the mature shear zone therefore consists of a series of deformed original grains stacked on top of each other in a manner which preserves original grain boundaries and intragranular features which develop during shear zone evolution the stability of some microstructures to higher shear strains the exploitation of others at lower shear strains and a continuously evolving crystal fabric mean that the strain gradient observed across many shear zones is unlikely to be equivalent to a time gradient

characterization of acid mine drainage sources in the iberian pyrite belt base methodology for quantifying affected areas and for environmental management the present work aims to propose a methodology for quantifying the sources of acid mine drainage amd and to characterize the magnitude of the affected areas in the iberian pyrite belt sw spain such an approach allows the creation of a support tool for managing land and natural resources valorization which may be easily applied in similar mining regions the motivation and usefulness of this work can be realized by focusing on two main emerging strategic issues 1 water resources management with the example of alcolea dam that will receive water from affected areas in the iberian pyrite belt and 2 mineral resources valorization especially regarding copper exploration due to increasing market prices the used methodology included the following general steps it started with an inventory of the mines in the iberian pyrite belt followed by field cartography campaigns and finally the quantification of affected areas and contaminant discharges the results of the present work serve to confirm and quantify the magnitude of the amd pollution in the pyrite belt a total affected area of about 4 847 ha was estimated taking into account this figure and combining it with the annual average precipitation 650 l m2 results in an estimation of 31 503 680 m3 year of discharging water affected by the presence of sulphides in this scenario a total annual contribution of 260 056 tonnes year was obtained for sulphates which means more than 712 tonnes a day in the case of arsenic a toxic element the total annual contribution is more than 20 tonnes or close to 55 kg day regarding copper this economically interesting metal translates into total contributions of 10 364 tonnes year in the generating medium this gave more than 28 tonnes day which today sits at 8 200 dollars tonne this result suggests that solutions aimed at recovering this resource should be searched it may represent a financial return at the same time that it would mean overcome environmental liabilities

stream water geochemistry from mine wastes in pena de hierro riotinto area sw spain a case of extreme acid mine drainage in this work we have studied the geochemistry of stream waters arising from waste dumps at the pena de hierro mine iberian pyrite belt sw spain and we have correlated them with the mineralogical and geochemical characteristics of the wastes to asses the source and factors affecting the release of trace elements the mineralogical composition and geochemistry of 58 borehole samples of waste dumps were studied in the 2 mm fraction twenty eight water samples collected in winter and summer from streams emerging from the waste dumps were analysed for ph eh conductivity temperature sulphates and major and trace elements the leachates from pyrite rich volcanic tuffs produced very acidic waters usually with phs below 2 and reaching values as low as 0 7 the partial dissolution of gossan which is mainly composed of fe oxy hydroxides and is rich in trace elements released high concentrations of fetot up to 33 g l as up to 72 mo up to 11 mg l on the other hand cd zn and pb reached up to 0 85 142 and 0 42 mg l respectively in the stream arising from roasted pyrite ashes and other pyritic wastes several elements such as al fe as co cu and mo were strongly correlated with the ph but cd and zn were not correlated under such acidic conditions the precipitation of jarosite seems to be an important factor in the retention of pb the mobility sequence of trace elements shows that co zn and cd were among the most mobile elements cu as and mo had intermediate mobility and pb was the most immobile this work shows that uncontrolled waste dumping increases the pollution potential and a selective management could reduce the release of trace elements into stream waters and mitigate the contamination

sem electron channelling analysis of dynamic recrystallization in a quartz grain abstract the sem electron channelling ec technique has been used to investigate the processes involved in the dynamic recrystallization of an individual quartz porphyroclast by using a combination of crystal axis polefigure diagrams and theoretical crystal axes dispersion paths for individual crystal slip systems it is possible to establish whether a relationship exists between recrystallized grains and parental grain it is then possible to distinguish between rotational and migrational dynamic recrystallization processes and to establish a dynamic recrystallization history for the porphyroclast dynamic recrystallization initiates as a subgrain rotation process initial rotation is accommodated by slip on individual systems leading to grain bending elongate polygonal subgrains and a systematic orientation relationship between subgrains and parent larger rotations and neoblast formation require more than one slip system but a systematic relationship between grains and parent can still be recognized rotational recrystallization produces an unstable microstructure which is stabilized by grainboundary migration

study on distribution characteristics of some water parameters properties of mine drainage in an oxidation pond hwangji yuchang coal mine south korea tracer test in situ distribution test and computational flow analysis at an oxidation pond consisting of passive treatment system treating coal mine drainage at the hwangji yuchang coal mine in south korea were performed to identify the distributed physicochemical and rheological characteristics of the acid mine drainage the influent mine water that flowed into the oxidation pond was at ph 6 79 and had 25 5 mg l of ferrous iron concentration and the flow rate was 59 3 m3 h as a result of the studies oxidation of fe2 in the oxidation pond was found to have mostly occurred near the inlet of the pond the distribution of the physical properties such as ph dissolved oxygen electric conductivity total dissolved solid turbidity ferrous concentration oxide reduction potential and water depth in the oxidizing pond was found to have been directly affected by the ferrous iron oxidation rate and rheological characteristics of the influent

geochemical study of different aged mining dump materials in the freiberg mining district germany historical mining dumps are useful archives for the investigation of weathering processes the objective of this study was to investigate the weathering behavior of waste rock material derived from the 800 year old silver ore mining in freiberg germany for identifying time dependent weathering indices dumped material of four dumps of different ages and corresponding rock was examined regarding the geochemical composition the dumped material is characterized by high contents of heavy metal containing sulfidic ores such as pyrite arsenopyrite sphalerite and galena acid mine drainage is produced by the oxidative weathering of the sulfide minerals and causes the increased dissolving of soluble metals with increasing age of dumps as a result of these weathering processes a clear depletion of chalcophile elements in the older dump material 800 years compared to the youngest dump 100 years was observed in the soil horizons downstream the dumps high quantities of heavy metals e g up to 12 000 ppm as 3 300 ppm pb 640 ppm zn mainly adsorbed on organic matter were determined and indicate a time dependent element transfer from the dumps into their surrounding soils

rio tinto estuary spain 5000 years of pollution mining of massive sulfide deposits in southwestern spain extending back to the copper and bronze ages has resulted in the pollution of the rio tinto fluvial estuarine complex the site of columbus departure for the new world in 1492 additional sources of potential pollution include the large industrial complex at huelva near the lower portion of the estuary extensive analysis of surface sediment samples and cores has established that there are no geographic trends in the distribution of the pollutants which include cu fe pb zn ti ba cr v and co these data have however demonstrated that tidal flux within the estuary carries phosphorus and perhaps other elements from the industrial complex at huelva to the tidal limit of the system several kilometers upstream from the discharge site radiometric analysis of short cores shows that sedimentation rates over at least the past couple of centuries have been about 0 3 cm year these data and that from a single deep core demonstrate that the estuary was polluted from mining activity long before the large scale operations began in the late nineteenth century

acid mine drainage in the iberian pyrite belt odiel river watershed huelva sw spain geochemistry mineralogy and environmental implications abstract this work reports the physical properties and water chemistry of 64 amd discharges from 25 different mines in the ipb draining to the odiel river watershed which have been investigated during the hydrologic year 2003 2004 these amd solutions vary largely in flow rate and chemical composition both spatially between the different mine sites suggesting a strong geologic control on amd chemistry and seasonally due to marked hydrologic variations and include cases with very low ph mostly in the range 1 4 4 and extreme sulphate up to 44 g l so 4 2 and metal content e g up to 7 7 g l fe 2 6 g l al or 1 4 g l zn different hydrogeochemical facies of amd namely fe ii anoxic fe iii suboxic and aluminous oxic are recognized in the field as a response to the continuous oxidation and hydrolysis of dissolved fe relevant geochemical aspects of these amd environments are discussed including i the redox chemistry of the fe ii fe iii couple ii the reaction rates for bacterially catalyzed oxidation of fe ii and hydrolysis of fe iii iii the role played by dissolved fe and al in the acidity and chemical buffering of the amd systems and iv the solubility and trace metal retention capacity of the fe oxyhydroxysulphate and hydrated sulphate minerals commonly associated with amd in addition the mineralogy and chemistry of the fe precipitates schwertmannite jarosite goethite ferrihydrite al phases e g basaluminite and mg fe al efflorescent so4 salts e g epsomite hexahydrite copiapite halotrichite rozenite coquimbite present in the amd generating mine sites have also been studied the mineralogy of the fe precipitates is well correlated with the water ph with jarosite at ph 2 schwertmannite at ph 2 4 basaluminite at ph 4 5 and ferrihydrite at ph 6 schwertmannite appears to be the most important mineral phase both in controlling the fe solubility at ph 2 4 and as sorbent of trace elements as cu zn which favours natural attenuation finally a basin scale environmental perspective is given in order to evaluate the impact of amd on the water quality including calculation of metal loadings transported by amd from the most important mine districts in the province

effect of acid mine drainage on a karst basin a case study on the high as coal mining area in guizhou province china acid mine drainage amd is a common pollution in mining areas due to the oxidation of pyrite and associated sulfide minerals at mines tailings and mine dumps elevated metals fe mn al and metalloids as hg in amd would deteriorate the local aquatic environment and influence the water supply a carbonate basin with deposits of high arsenic coal in xingren county southwestern china was chosen to study the behavior of as and other chemical constituents along a river receiving amd heavy metals fe mn and major ions such as ca2 mg2 cl so42 in surface water and as in sediment and surface water were analyzed it was found that high concentrations of so42 1 324 7 560 mg l and fe 369 1 472 mg l in surface water were mainly controlled by the interactions between water and rocks such as the oxidation of pyrite in the local coal seams precipitation and adsorption of iron minerals although ubiquitous carbonate minerals in the bedrock and the riverbeds low ph 3 water was maintained until 2 km downstream from the amd source due to the fe hydro oxide minerals coating on the surface of carbonate minerals to restrain the neutralization of acidic water moreover the formation of fe hydro oxide precipitations absorbed as was dominated the attenuation of as from water to sediment whereas the dilution also played an important role in decrease of as in river water

geochemical characteristics of heavy metal pollution in surface sediments of the tinto and odiel river estuary southwestern spain the study of the geochemical composition of 52 samples of surface sediments from the tinto and odiel river estuary shows high concentration rates of fe 11 21 cu 928 ppm zn 1 146 ppm pb 730 ppm and ba 660 ppm high concentrations of metals are caused by the river contribution of sediments from areas with a high mining activity and from the industrial activity carried out on the estuary banks estuary sediments are divided into four groups group 1 formed by low polluted siliciclastic gravel and sand group 2 of highly polluted muddy sediments of river origin group 3 formed by sandy muds of mixed origin with an average pollution rate and group 4 formed by muddy sediments from the system s inner zones with an intermediate high pollution rate in all the cases the coefficients of metallic enrichment are high superiors at 9 except for the fe indicating a high capacity of dispersion of the load metallic pollutant

grain boundary hierarchy development in a quartz mylonite abstract orientation contrast imaging using forescatter detectors and backscattered electron diffraction techniques in the scanning electron microscope have been used to investigate the boundary hierarchy characteristics of a quartz mylonite shear zone from torridon nw scotland the boundary hierarchy is defined as the relationship between the boundary misorientations their enclosed domain size and their frequency distribution by measuring the misorientation across every grain and subgrain boundary the characteristics of the boundary hierarchy can be found two microstructural domains were studied one partially recrystallized low strain domain with large relict grains and one fully recrystallized high strain mylonitic domain our results indicate that the processes of recovery subgrain rotation and grain boundary migration recrystallization each produce identifiable boundary hierarchy signatures in the relict quartz grains we have identified the processes of recovery and subgrain rotation in the recrystallized quartz a cyclic steady state exists between these and other processes coupling these data with traditional microstructural observations allows a more rigorous investigation into the development of a high strain fine grained mylonite from a coarse grained undeformed protolith we suggest that this type of detailed crystallographic microstructural analysis can greatly further our understanding of microstructural development in shear zones and may have implications for the effective use of sub grain size palaeopiezometers

the natural attenuation of two acidic effluents in tharsis and la zarza perrunal mines iberian pyrite belt huelva spain the geochemical evolution of two acid mine effluents in tharsis and la zarza perrunal mines iberian pyrite belt huelva spain has been investigated in origin these waters present a low ph 2 2 and 3 1 and high concentrations of dissolved sulphate and metals fe al mn cu zn as cd co cr ni however the natural evolution of these acidic waters which includes the bacterial oxidation of fe ii and the subsequent precipitation of fe iii minerals represents an efficient mechanism of attenuation this self mitigating process is evidenced by the formation of schwertmannite which retains most of the iron load and by sorption toxic trace elements like as the later mixing with pristine waters rises the ph and favours the total precipitation of fe iii at ph 3 5 and subsequently al compounds at ph 4 5 along with the sorption of trace metals mn zn cu cd co ni until chemical equilibrium at circumneutral conditions is achieved

4 500 year old mining pollution in southwestern spain long term implications for modern mining pollution the tinto river drains the rio tinto mining district which comprises the world s largest known massive sulfide deposits these orebodies have been mined from the third millenium bc to the present the tinto river is strongly acidic ph 1 5 2 5 during flood events it transports a sandy material including abundant detrital pyrite grains a core drilled in the holocene sediments of the tinto estuary allows for investigation of recent and historical mining pollution two anomalous horizons have been recognized 0 1 3 m 3 4 m both are characterized by very high metal content 100 times over the background and by the presence of abundant clastic pyrite grains the metal association pb ba as cu zn sn tl cd ag hg au is typical of that of the rio tinto pyritic ore the upper horizon corresponds to the modern mining activity the lower horizon has been dated at 2530 bc 14c ams calibrated age we show here that active mining occurred early copper age in the rio tinto area resulting in a watershed scale metal contamination we also show that anthropogenic input of metals may be accumulated and immobilized during thousands of years in estuarine sediments

water chemistry and heavy metal distribution in an amd highly contaminated river environmental impacts of acid mine drainage amd from dexing copper mine the largest open pit copper mine in asia on le an river were well documented 10 years ago however ore production of the mine has increased fourfold and the contamination situation of the river now is unknown our studies indicated that heavy metal concentrations in riverwaters dissolved suspended solids ss and sediments all showed highly localized distribution patterns closely associated with two amd contaminated tributaries dawu river and ji river and are significantly different from the previous findings compared with the previous reports most of the sampling sites in le an river displayed lower contents of sediments of 2005 because several historical upstream and downstream heavy metal sources disappeared or became unimportant the surprised decrease of copper contents in sediments at the mixing location with dawu river was mainly due to dilution from the sufficient input of poor copper ore 0 3

mineralogical and geochemical spatial analyses of a waste rock dump at the libiola fe cu sulphide mine eastern liguria italy in this work we investigated a 3 ha sulphide bearing waste rock dump libiola mine italy using mineralogical geochemical and geostatistical analyses the dumped materials were highly heterogeneous in grain size and lithology and varied both laterally and vertically other than the host rock of the ore basalts and serpentinites the dumped materials contained high amounts of low grade chalcopyrite and pyrite rich mineralisations due to these characteristics and to the absence of minerals able to neutralise acidity this waste rock dump can be classified as an acid mine drainage amd producer the study confirms that amd is still active and in the best scenario can persist for up to 6 17 103 years the consequences of this process are of serious environmental concern as it involves strong acidification of the circulating waters the release of potentially toxic metals into the soil streams and rivers and the precipitation of huge quantities of secondary fe oxides and fe oxyhydroxides

monitoring study of the mine pond reclamation of mina concepcion iberian pyrite belt spain mining of massive cu pb and zn sulphide bodies in the iberian pyrite belt sw spain has generated a great number of abandoned waste deposits such as mine ponds these represent large accumulations of reactive minerals and subsequently emission sources of trace elements and formation of acid drainage even if they have been restored monitoring studies are required to evaluate the corrective effects and how they may change over time this work presents the results of a monitoring study carried out at mine concepcion mine pond based on mineralogical xrd geochemical inaa x ray fluorescence icp ms and geophysical electrical resistivity tomography techniques in it a series of relevant parameters have been well delimited such as the infilling thickness and its variation and the position geometry and absence of water leakages through the base of the mine pond additionally the existence of an internal remnant flow of acid waters that tends to come out through the pond dyke has been identified chemistry of these waters indicates that oxidation processes affecting the mina concepcion mine tailings are generating acid drainage waters which could potentially release substantial amounts of trace elements to the river odiel thus giving that not complete sealing is accomplished by the restoration capping and rainfall water infiltrates into the pond materials at least the sealing of the dyke through which leakages occur should be revised

the osmium isotopic composition of the continental crust osmium isotopic compositions and concentrations have been determined for deltaic and continental shelf sediments from three major rivers the amazon changjiang and mississippi and for two loesses from the upper mississippi river valley the loesses have heavy mineral and clay compositions characteristic of mississippi river and delta sediment concentrations range from 15 to 120 pg os g and 187os 186os ratios range from 8 2 to 10 9 sediments which are polluted surface sediment from the changjiang estuary or which have scavenged metals from seawater gulf of mexico slope surface sediment and distal amazon shelf sediment have high osmium concentrations and less radiogenic isotopic compositions purely terrigenous sediments have 15 90 pg os g and 187os 186os 10 0 10 9 north american loess and mississippi delta sediment osmium isotopic compositions are indistinguishable we believe that 187os 186os 10 11 is a good average for currently eroding upper continental crust these sediments have neodymium isotopic compositions close to the global mean for river sediment terrigenous 187os 186os is significantly more radiogenic than seawater 187os 186os 8 6 requiring a nonriverine source of osmium to seawater terrigenous osmium is also significantly more radiogenic than bulk pelagic clay osmium we use the improved estimate of terrigenous 187os 186os to recalculate the flux of extraterrestrial osmium to pacific marine sediment if the residence age of osmium in an upper crustal region is similar to the neodymium model age of a sediment derived from that region a model dependent upper crustal 187re 186os ratio can be calculated for the model ages of the sediments analyzed in this study tdm 1 5 1 7 ga model 187re 186os ratios are 340 360 and can be used to correct for bias resulting from the preferential erosion of young crust the 187os 186os ratio of 2 2 ga crust with 187re 186os 400 is 14 2 we have also used the data from this study to estimate upper crustal osmium and rhenium concentrations of 50 pg g and 390 pg g respectively

dissolved and particulate metals and arsenic species mobility along a stream affected by acid mine drainage in the iberian pyrite belt sw spain abstract intensive mining has taken place in the iberian pyrite belt since 3000 b c generating acid mine drainage amd and releasing high amounts of so 4 acidity metals and metalloids into surface water concentrations of elements in amd impacted waters are regulated by the precipitation of fe rich materials and particulate matter can influence the mobility and the bioavailability of metals in this paper a study on the dissolved as species concentration along a polluted stream has been performed two sampling campaigns were conducted during the dry and the rainy seasons concentrations of dissolved elements are higher during the dry season and increase progressively along the water course in both seasons concentrations up to 80 g l 1 of as 3 and 5 mg l 1 of as 5 were determined the concentration of as species increases and the as 3 as 5 ratio decreases downstream the fe 2 fe 3 and as 3 as 5 ratios show the same pattern with respect to ph for all the examined samples except those taken from au cyanidation wastes the particulate phase is mainly composed of fe as and pb with as being associated with the fe minerals while pb seems to be associated with the clay colloids

heavy metal mobility assessment in sediments from the odiel river iberian pyritic belt using sequential extraction the tessier sequential extraction scheme ses was applied to sediments from the odiel river catchment iberian pyritic belt sw of spain one of the most acid rivers on earth to assess the chemical association exchangeable carbonatic bound to manganese and iron oxides bound to organic matter and residual mineral of heavy metals zn cd pb cu cr mn ni fe and hg sediments are very heterogeneous in their textural characteristics showing different grain size twenty seven samples were studied from from areas along the odiel river from the source to the mouth with special interest in the odiel marshes natural park due to its ecological significance samples were classified as sandy especially at the river mouth with low iron oxide and organic matter content and clay silty in the middle of the river catchment with high iron oxide content the numerous sandy samples with low ph values explain the low levels of metals upstream although potential metals contributions arise from mining and ore however the presence of sulfate in the mining area and carbonate at the mouth may explain the high presence of lead and iron in these sandy zones some percentage of mobile ni cu and zn were detected in the mining area but the elevated relative percentage of exchangeable cd in the estuary is even more remarkable the percentage of zn bound to carbonate is considerable in the catchment but especially in the estuary however cu is only detected in the carbonate phase downstream in spite of the low concentration of carbonate which represents a drawback in the application of the tessier ses to these types of samples finally relatively high percentages of residual non mobile hg and pb were observed in the estuarine and mining areas respectively sand lime and clay fractions of representative samples from areas i ii and iii were used in a metal speciation study mainly the elements analyzed had accumulated in the non residual fractions in the mining area of the pyrite belt the elements analyzed are mainly bound to fe mn oxides fe mn cu cr pb mn zn and the organic matter sulfide fraction ni zn hg cd independent of sediment grain size in conclusion we show that the results of the study of chemical speciation in sediments from acid rivers are independent of the sediment grain size considered

hyperspectral remote sensing monitoring of pyrite mine wastes a record of climate variability pyrite belt spain monitoring of mine waste on sulphide deposits through hyperspectral remote sensing data contributes to predicting surface water quality quantitatively estimating acid drainage and metal contamination on a yearly basis the mineralogy of surface crusts loaded with highly soluble salts is a record of available humidity and temperature along the year a temporal monitoring of salt efflorescence on mine wastes at a mine site in the iberian pyrite belt spain has been mapped in this work using hyperspectral airborne hymap data climate change estimations are made based on oxidation stages derived from well known sequences of minerals tracing sulphides oxidation intensity using archive spectral libraries therefore mine waste weathering products of sulphide mapped from airborne hyperspectral remote sensing data can be used as a short term record of climate change providing a useful tool for assessing environmental geoindicators in semi arid areas

evidence for dominant grain boundary sliding deformation in greenschist and amphibolite grade polymineralic ultramylonites from the redbank deformed zone central australia abstract microstructural and textural investigations by scanning sem and transmission electron microscopy tem techniques have been performed on samples taken across two quartzo feldspathic mylonite zones from the redbank deformed zone central australia one has been deformed at greenschist facies gs the second at amphibolite facies am conditions with increasing strain the rock type changes from protomylonite to mylonite to ultramylonite the protomylonites and mylonites consist of alternating quartz and polymineralic quartz feldspar bands at the highest strains a homogeneous fine grained polymineralic ultramylonite occurs shear zone geometry and microscale structures indicate that these ultramylonites experienced higher strains and were weaker than the encapsulating protomylonites and mylonites tem and sem studies of the ultramylonites reveal a rectangular to square grain shape a continuous alignment of grain and interphase boundaries across several grain diameters a grain size gs 0 5 m am 5 11 m less than the equilibrium subgrain size and open and void containing grain and interphase boundaries analysis of local textures by electron back scatter diffraction ebsd in the sem showed a very weak crystallographic preferred orientation cpo for the quartz the grain misorientation relationships are not consistent with dislocation creep being the dominant deformation mechanism all structures are of the type expected if grain boundary sliding processes had contributed significantly to the deformation consequently the deformation of such quartzo feldspathic rocks and by implication the rheology of the redbank deformed zone must have been controlled by the mechanical properties of these fine grained polymineralic ultramylonites deforming by grain boundary sliding processes this is in contrast to the pure quartz bands which deformed by dislocation creep mechanisms and were less important in the rheology of the redbank deformed zone

synkinematic microscopy of transparent polycrystals abstract deformation of weak polycrystalline materials in thin section on the stage of a petrographic microscope offers insight into the origin of optical microstructures similar to microstructures in naturally deformed rocks sample materials used to date include several soft minerals ice carnallite bischofite nitratite and various organic plastic materials they can be simple sheared or pure sheared at temperatures to 300 c at a variety of strain rates using relatively simple and inexpensive apparatus the complete microstructural evolution can be recorded photographically along with the complete kinematic history research applications have focussed on dynamic recrystallization and progress has been made towards understanding how the average grain size is maintained constant in steady state recrystallization flow records have been obtained of the development of various crystal plastic microstructures and of lattice reorientation trajectories during flow teaching applications have begun to be developed and several videotapes are available future technical developments are expected to permit stress measurement or control during experiments and synkinematic recording of lattice reorientation numerous research areas invite attention these include investigation of the microstructural developments that precede faulting the behaviour of deforming crystal melt systems and the behaviour of dynamically reactive multi phase systems