the nature of the plate interface and driving force of interseismic deformation in the new zealand plate boundary zone revealed by the continuous gps velocity field 1 new zealand straddles the boundary between the australian and pacific plates cenozoic relative plate motion has resulted in a complex pattern of faulting and block rotation with displacements on individual faults up to hundreds of kilometers however over periods of several years gps measurements show a remarkably smooth pattern of velocities we show here using a new method of back slip analysis that almost the entire plate boundary continuous gps velocity field can be predicted within measurement error from a simple model of elastic distortion due to deep slip on a single plate interface megathrust in the hikurangi and putsegur subduction zones or fault through continental lithosphere beneath the southern alps at the relative plate motion rates this suggests that the main driving force of plate boundary deformation is slip on the deeper moving part of the plate interface without buried creep in localized shear zones beneath individual surface faults the depth at which this deep slip terminates locking point line determines the width of deformation along the hikurangi margin there is also clockwise rotation of 150 km long segment of the fore arc wairoa domain at 4 5 1 ma relative to the australian plate about a pole in western north island model residuals in the velocity field are mainly a result of incomplete averaging of the cycle of slow slip events on the plate interface downdip of the locking point

controls on pit lake water quality at sixteen open pit mines in nevada thirty five mines in nevada currently have or will likely have a pit lake the large bulk mineable deposits in nevada mined below the water table are of several types including carlin type au quartz adularia precious metal quartz alunite precious metal and porphyry cu mo deposits of the 16 past or existing pit lakes at 12 different nevada mines most had near neutral ph and low metal concentrations yet most had at least one constituent e g so4 which exceeded drinking water standards for at least one sampling event water quality data indicate that in general poor water quality will not develop in carlin type au deposits wall rocks in the geologic environment typical of these deposits and in the specific pits sampled contain substantial amounts of carbonate which buffers the ph at slightly basic conditions and thereby limits the solubility of most metals similarly the quartz adularia precious metal deposits generally have geologic conditions that buffer ph and naturally prevent the development of poor water quality in both of these deposit types certain elements such as as and se that are mobile in neutral to basic waters may accumulate to levels near or exceeding drinking water standards pit lakes forming in quartz alunite precious metal deposits hosted in volcanic rocks or in porphyry cu mo deposits in plutonic rocks are of greatest environmental concern in nevada as both deposit types have relatively high acid generating potential and low buffering capacity however the sampled nevada pits in these deposit types indicate that the water may not be of poor quality in addition water quality in some pits may actually improve with time due to the increased water rock ratio as the pit fills with water as suggested by pit waters at one mine in a carlin type deposit getchell that improved between 1968 and 1982 although water quality in pits in each deposit type is generally good local site specific conditions e g surface water inflow and variations e g evaporation rates result in some pit lakes e g boss in the quartz adularia deposit type being of substantially poorer water quality than other lakes e g tuscarora in the same deposit type despite underlying geologic controls based on deposit type site specific variations in hydrogeologic conditions and surface geologic features can result in differing water quality in pit lakes in the same deposit types and these factors may in some cases provide an overriding control on the geochemical evolution of specific pit lakes

the role of surface water and mine groundwater in the chemical stratification of an acidic pit lake iberian pyrite belt spain summary the hydraulic system of the concepcion mine is made up of an open pit and an underground mine which are currently flooded and hydraulically connected the concepcion pit lake has shown permanent chemical stratification meromictic lake where two layers with different density and chemical composition can be differentiated i a thick superficial layer of 11 2 m deep with a low concentration of dissolved solids mixolimnion and ii a thin bottom layer from 11 2 m to 16 m deep monimolimnion exhibiting vertical changes in its physico chemical parameters with decreasing redox potential and increasing t ph and dissolved solids content with depth the distribution of the concepcion pit lake layers depends on recharge processes and the loss of water from the system in winter rainfall and runoff result in a rapid increase of lake levels the lake regains its initial level whenever water is lost through an old mine adit since galleries and shafts act as preferential pathways for inflowing and outflowing water this network is connected to the bottom of the lake resulting in the progressive downward movement of the chemocline furthermore runoff generates a less dense superficial layer which triggers the development of an ephemeral chemocline in the mixolimnion in summer the mixolimnion loses water by evaporation which is partially compensated by groundwater inflowing from the lake bottom resulting in the upward movement of the permanent chemocline during this period the water level in the system is below the outlet level which therefore renders the outflow of water inactive during this stage the mixolimnion remains homogeneous and the shallow chemocline disappears taking into consideration the hydrochemical characteristics of this pit lake and the spatial distribution of the layers identified a model that explains its seasonal limnological evolution is presented

rates of low ph biological fe ii oxidation in the appalachian bituminous coal basin and the iberian pyrite belt low ph fe ii oxidation can be exploited for the treatment of acid mine drainage amd however natural or engineered terraced iron formations tifs are underutilized for amd treatment because of uncertainties with respect to treatment performance to address this problem we measured the rates of fe ii oxidation multiple times at eight sites in the appalachian bituminous coal basin and at three sites in the iberian pyrite belt ipb longitudinal geochemical transects were measured downstream of emergent anoxic amd sources water velocities were measured at each sampling location and used to transform concentration versus distance profiles into concentration versus travel time for kinetic analysis of field data zero order fe ii oxidation rates ranged from 8 60 to 81 3 10 7 mol l

stable isotope geochemistry of acid mine drainage from the wiśniowka area south central poland abstract this paper presents the results of a current isotopic study of pyrite mineralization acid mine drainage amd and nearby rivers and farmer s wells located in the western part of the main range holy cross mountains south central poland the principal source of dissolved sulfates in acid lakes ponds and intermittent pools is the predominant microscopic grained and locally framboidal pyrite fes2 that tends to oxidize rapidly on exposed quarry walls and unvegetated historic and current tailings piles this process is expedited by the occurrence of arsenic in the pyrite crystal structure which greatly decreases its resistance to weathering the 34s signature of pyrite from the podwi niowka quarry mean of 24 0 3 1 was different from that of the wi niowka duza quarry mean of 17 4 7 2 these values fingerprinted two basic pyrite mineralization zones assigned to lowermost and middle upper cambrian rock series respectively the 34s fes2 differences also were reflected in dissolved sulfates that displayed distinctly different 34s values 15 3 1 0 podwi niowka and 10 0 1 7 wi niowka duza these negative 34s values stand in contrast to their positive equivalents of the cambrian main range as well as in the examined rivers and farmer s wells unaffected by amd processes the acid water bodies also displayed diverse seasonal variations of 34s so42 18o so42 and 18o h2o that were linked to surface area site topography exposition to radiation changing weather patterns especially temperature and a periodical influx of rainwater or meltwater the isotope data also suggest that evaporation occurred after pyrite oxidation without a direct contact with lake pond waters which is also evidenced by the occurrence of sulfate efflorescences on podwi niowka and wi niowka quarry faces the stable s o and h isotopes have been employed for fingerprinting different geochemical processes and for assessing a potential impact of amd waters on nearby rivers and local perched aquifers particularly in case of no visual indications the s isotope signatures of ponds and pools have also been used for determining the provenance of historic and recent mine waste material

the aqueous geochemistry of the berkeley pit butte montana u s a water levels in the berkeley pit butte montana are currently rising approximately 22m per year following the cessation of pumping in 1982 projections suggest that the pit may be filled to capacity at the 5520 ft 1682 m elevation by the year 2009 if remedial action is not implemented in addition as the water level in the pit continues to rise there is the potential for encroachment of contaminated water into the alluvial aquifer and subsequent transport of metals downgradient to silver bow creek geochemical measurements and aqueous samples collected during october 1987 indicate that water in the berkeley pit is moderately oxidizing eh 460mv below 30 m acidic ph 3 0 cafe sulfate solution the principal ions are al as ca cd cu fe k mg na so4 and zn which typically increase in concentration from the surface to the bottom of the pit arsenic occurs mainly as as v in total metal concentrations up to 1 mg l fe as fe iii in the top 3 m and as fe ii below this depth in concentrations up to 1000 mg l sulfate was measured in concentrations up to 6780 mg l from the deepest 130 m sample copper and zn were found in total metal concentrations of 202 and 512 mg l respectively at the 130 m sampling depth to verify the field eh measurements minteq was used to calculate a theoretical eh based on the fe ii fe iii couples the results suggest that the ratio fe ii fe iii is representative of the system eh when both species occur in measurable quantities 0 25mg l and when the minor species constitutes at least 5 of the total concentration data from this study were used in the geochemical computer code phreeqe to evaluate potential remediation of the water body through the addition of alkaline tailings fluid produced at the current milling operation on site five cases were evaluated two representative of conditions under ice cover pco2 not fixed and three open system simulations pco2 10 3 5 mineral controls included fe oh 3 gypsum caso4 2h2o jurbanite alohso4 and jarosite kfe3 so4 2 oh 6 the addition of three volumes of alkaline slurry to the existing volume of acidic fluid would raise the ph to 5 0 this option would take approximately 7 a at the current rate of production 11 6 million gallons per day 43 9 ml d at this time the fluid level would be approximately 20 m above the alluvial bedrock contact

the acidic mine pit lakes of the iberian pyrite belt an approach to their physical limnology and hydrogeochemistry abstract this study examines some relevant limnological and hydrogeochemical characteristics of 22 mine pit lakes of the iberian pyrite belt ipb the studied pit lakes include some of the largest and historically most important mines of the ipb including corta atalaya and cerro colorado in riotinto filon norte filon centro and filon sur in tharsis aznalcollar or san telmo and many other of minor size as a whole these lakes constitute at present a large volume of highly acidic and metal polluted water some of these pit lakes are very recent e g corta atalaya 2 5 a los frailes 6 a and present a continuous hydrological and geochemical evolution although many others were abandoned decades ago and show nearly constant water volume depth profiles obtained in several pit lakes e g san telmo confesionarios cueva de la mora concepcion indicate that many of them have developed meromixis and show at present a permanent thermal and chemical stratification with a well defined chemocline separating an anoxic fe ii rich monimolimnion and a well mixed oxygenated and fe iii rich mixolimnion in the upper layer the bacterial oxidation of fe ii competes with photoreductive processes which take place in the surface water thus provoking diel cycles of fe ii concentration the observed water chemistry reflects the oxidation and dissolution of pyrite and other sulphides and gangue aluminosilicates from the country rock the pit lakes of the ipb cover a wide range of water compositions from circumneutral and relatively low metal e g los frailes ph 7 2 0 07 mg l fe 3 8 mg l mn 30 mg l zn to extremely acidic and metal loid rich e g corta atalaya ph 1 2 36 7 g l fe 6 7 g l zn 1 3 g l cu 159 mg l as most pit lakes however are comprised within the ph range of 2 2 3 6 and appear to be strongly buffered by the hydrolysis and precipitation of fe iii in the form of schwertmannite which forms colloids that can sorb trace elements from the aqueous phase

the properties of reservoir water in post mining excavations of cambrian and devonian quartzite sandstones holy cross mountains in the holy cross mountains southern poland there are numerous disused quarries some of these are filled with water and some despite their nearby location have extremely diverse physicochemical and chemical properties of their waters one such object is the wi niowka mala reservoir its waters contain large amounts of sulfates 700 mg l and iron 24 mg l which are weathering products of rocks containing metal sulfides mainly pyrite in the direct drainage zone as a consequence there is an increase in the electrolytic conductivity of the water supplying the reservoir resulting in very low ph values 4 this article presents the detailed limnological characteristics of this reservoir and explains the process that led to its water acidification a control reservoir barcza was also selected for the tests although it is also a post mining excavation it has a neutral ph and a low concentration of sulfates and iron the examined reservoirs differ in the hydrochemical type of waters the wi niowka mala reservoir represents a sulfate calcium double ion type so42 ca2 and the barcza reservoir a bicarbonate calcium type hco3 ca2 the concentrations of the main ions occurring here are shaped by the lithological features of the surrounding rocks respectively upper cambrian quartzite sandstones with pyrite mineralization zones lower devonian sandstones cut by mudstones and claystones with tuffite inserts

modulation of northern hemisphere wintertime stationary planetary wave activity east asian climate relationships by the quasi biennial oscillation 1 the modulation of the relationship between the tropospheric stationary planetary wave activity and the east asian winter climate by the tropical quasi biennial oscillation qbo wind in the stratosphere is investigated in the qbo easterly phase a significant warming appears in northeastern asia in the presence of high wave activities this corresponds to a weakened east asian trough at 500 hpa which determines the extent to which cold waves penetrate into east asia however in the qbo westerly phase both the surface warming and the weakening of the east asian trough become insignificant in response to high wave activities the possible mechanism for this qbo modulation on the tropospheric wave activities may be attributed to the indirect influence of the qbo induced polar and extratropical stratospheric circulation changes under the qbo easterly phase conditions the tropospheric wave activity flux divergence in the higher latitude region is enhanced due to enhanced upward eliassen palm ep flux into the stratosphere while the wave flux convergence in the subtropical troposphere is increased due to the decrease in the equatorward flux this leads to an enhanced wave activity difference and thus the associated east asian climate anomalies become larger and robust an opposite effect i e reduced wave activity difference appears in the qbo westerly phase further analyses reveal that the qbo significantly modulates both the zonal wave number 1 and 2 in the sea level pressure field but not for wave number 3 the combination of wave number 1 and 2 patterns leads to the strongest surface temperature anomalies in northern asia

geochemistry and stable isotope investigation of acid mine drainage associated with abandoned coal mines in central montana usa the great falls lewistown coal field gflcf in central montana contains over 400 abandoned underground coal mines many of which are discharging acidic water with serious environmental consequences areas of the mines that are completely submerged by groundwater have circum neutral ph and relatively low concentrations of metals whereas areas that are only partially flooded or freely draining have acidic ph 3 and high concentrations of metals the ph of the mine drains either decreases or increases after discharging to the surface depending on the initial ratio of acidity mainly al and fe2 to alkalinity mainly hco3 in acidic fe rich waters oxidation of fe2 after exposure to air is microbially catalyzed and follows zero order kinetics with computed rate constants falling in the range of 0 97 to 1 25 mmol l 1 h 1 in contrast fe2 oxidation in near neutral ph waters appears to be first order with respect to fe2 concentration although insufficient data were collected to constrain the rate law expression rates of fe2 oxidation in the field are dependent on temperature such that lower fe2 concentrations were measured in down gradient waters during the day and higher concentrations at night diel cycles in dissolved concentrations of zn and other trace metals mn ni were also noted for down gradient waters that were net alkaline but not in the acidic drains the coal seams of the gflcf and overlying cretaceous sandstones form a perched aquifer that lies 50 m above the regional water table situated in the underlying madison limestone the d and 18o values of flooded mine waters suggest local derivation from meteoric water that has been partially evaporated in agricultural soils overlying the coal mines the s and o isotopic composition of dissolved sulfate in the low ph mine drains is consistent with oxidation of biogenic pyrite in coal under aerated conditions a clear distinction exists between the isotopic composition of sulfate in the acid mine waters and sulfate in the adjacent sedimentary aquifers making it theoretically possible to determine if acid drainage from the coal mines has leaked into the underlying madison aquifer

geochemistry of the rare earth elements and uranium in the acidic berkeley pit lake butte montana abstract filtered 0 45 m and nonfiltered concentrations of rare earth elements ree u zr th ba sc and y were measured as a function of depth in the berkeley pit lake a large acidic mining lake in butte mt the ree show very little variation with depth apart from a slight concentration near the surface presumably due to evaporation the ree profiles of the pit waters show a depletion in light ree when normalized against nasc and the host butte quartz monzonite bqm and a possible enrichment in middle ree vs heavy ree when normalized against bqm all of the ree partitioned weakly into secondary ferric precipitates formed by aging of deep berkeley pit water the measured distribution coefficients increased across the lanthanide series from la kd 7 7 to nd kd 10 3 and then decreased steadily to lu kd 1 4 under the conditions of the berkeley pit lake the aqueous speciation of ree and u is dominated by sulfate complexes because the stability constants of ree sulfate complexes show very little variation across the lanthanide series the observed trends in kd cannot be explained by aqueous complexation despite high concentrations of dissolved ree e g 1 1 mg l ce and u 0 85 mg l saturation indices for all solid phases were strongly negative due to the low ph of the berkeley pit lake 2 3 2 6 the mobility of ree and u is more likely constrained by adsorption or co precipitation with strengite jarosite schwertmannite or other secondary minerals forming in the lake

sulfur isotope studies to quantify sulfate components in water of flooded lignite open pits lake goitsche germany abstract a system of connected lignite mining pits part of the former goitsche mining complex germany was flooded with river water between 1999 and 2002 a considerable accumulation of acid associated with oxidized sulfides in sediments was seen as a critical point for the development of the lake water to characterize the components contributing to the supply of dissolved lake water so4 hydro chemical and isotope investigations with respect to groundwater pore water in the sulfide bearing sediments river water and lake water were performed 34s of pore water so4 that was dominated by oxidized pyrites ranges around 25 vcdt and differs strongly from river water so4 with about 4 4 thus interactions between lake water and sediments were particularly pronounced during the first phase of flooding for this period a more quantitative estimation of the so4 components in the lake water was difficult because of the heterogeneous so4 distributions between the different sub basins of the lake and according to the flooding process itself later a component separation was attempted following mixing of the whole lake which first occurred in spring 2002 a very heterogeneous groundwater environment with respect to highly variable so4 concentrations and 34s values and changing interaction with the forming lakes proved to be one of the most important limitations in the calculations of the mixing

geochemistry of highly acidic mine water following disposal into a natural lake with carbonate bedrock abstract acid mine drainage amd from the zn pb ag bi cu deposit of cerro de pasco central peru and waste water from a cu extraction plant has been discharged since 1981 into lake yanamate a natural lake with carbonate bedrock the lake has developed a highly acidic ph of 1 mean lake water chemistry was characterized by 16 775 mg l acidity as caco3 4330 mg l fe and 29 250 mg l so4 mean trace element concentrations were 86 8 mg l cu 493 mg l zn 2 9 mg l pb and 48 mg l as which did not differ greatly from the discharged amd most elements showed increasing concentrations from the surface to the lake bottom at a maximal depth of 41 m e g from 3581 to 5433 mg l fe and 25 609 to 35 959 mg l so4 the variations in the h and o isotope compositions and the element concentrations within the upper 10 m of the water column suggest mixing with recently discharged amd shallow groundwater and precipitation waters below 15 m a stagnant zone had developed gypsum saturation index si 0 25 and anglesite si 0 1 were in equilibrium with lake water jarosite was oversaturated si 1 7 in the upper part of the water column resulting in downward settling and re dissolution in the lower part of the water column si 0 7 accordingly jarosite was only found in sediments from less than 7 m water depth at the lake bottom a layer of gel like material 90 wt water of ph 1 with a total organic c content of up to 4 40 wet wt originated from the kerosene discharge of the cu extraction plant and had contaminant element concentrations similar to the lake water below the organic layer followed a layer of gypsum with ph 1 5 which overlaid the dissolving carbonate sediments of ph 5 3 7 in these two layers the contaminant elements were enriched compared to lake water in the sequence as

spring water trace element geochemistry a tool for resource assessment and reconnaissance mineral exploration abstract geochemical data from 151 spring locations within the 37 000 km2 south nahanni river basin of the mackenzie mountains northwest territories were analysed as part of a reconnaissance assessment of mineral potential in this large and remote region statistical data analyses graphical methods and strategic grouping of springs according to geochemistry ph and temperature were used to identify regions with higher mineralization potential quickly and efficiently testing of internal consistency indicates that known world class deposits within the basin are readily detected but by different methods as different deposit types have different geochemical signatures a new 3 component approach was developed to analyze trace element data for signatures of mineralisation estimation of circulation depth and therefore maximum potential ore depth further refines the assessment of economic potential the depth of circulation of the spring waters ranged from 4 7 km to less than 200 m for the entire dataset in total 62 spring locations were identified as having anomalous trace metal content by one or more method approximately 40 of the dataset specifically 11 spring locations were classified as anomalous by all three methods and 17 by at least two methods and 34 by only one method

low frequency earthquakes below southern vancouver island 1 the nature and distribution of low frequency earthquakes lfes in subduction zones provide insight into plate boundary deformation downdip of the locked seismogenic zone we employ network autocorrelation detection to identify lfe families beneath southern vancouver island and environs an initial suite of 5775 lfes detected in 2004 and 2005 at a select set of 7 stations is grouped into 140 families using waveform cluster analysis these families are used as templates within an iterative network cross correlation scheme to detect lfes across different tremor episodes incorporate new stations and improve lfe template signal to noise ratio as in southwest japan representative lfe locations define a relatively tight dipping surface several km above the locus of intraslab seismicity within a prominent dipping low velocity zone lvz lfe polarizations for near vertical source receiver geometries possess a remarkably uniform dipolar signature indicative of point source double couple excitation focal mechanisms determined fromp wave first motions are characterized by a combination of strike slip and thrust faulting we suggest that lfes and regular intraslab seismicity occur in distinct structural and stress regimes the lvz inferred to represent weak overpressured porous and mylonitized metabasalts of oceanic crustal layer 2 separates lfes manifesting deformation within a plate boundary shear zone from intraslab earthquakes generated by tensional stresses and dehydration embrittlement within a more competent lower oceanic crustal layer 3 and underlying mantle

low frequency earthquakes reveal punctuated slow slip on the deep extent of the alpine fault new zealand we present the first evidence of low frequency earthquakes lfes associated with the deep extension of the transpressional alpine fault beneath the central southern alps of new zealand our database comprises a temporally continuous 36 month long catalog of 8760 lfes within 14 families to generate this catalog we first identify 14 primary template lfes within known periods of seismic tremor and use these templates to detect similar events in an iterative stacking and cross correlation routine the hypocentres of 12 of the 14 lfe families lie within 10 km of the inferred location of the alpine fault at depths of approximately 20 30 km in a zone of high p wave attenuation low p wave speeds and high seismic reflectivity the lfe catalog consists of persistent discrete events punctuated by swarm like bursts of activity associated with previously and newly identified tremor periods the magnitudes of the lfes range between ml 0 8 and ml 1 8 with an average of ml 0 5 we find that the frequency magnitude distribution of the lfe catalog both as a whole and within individual families is not consistent with a power law but that individual families frequency amplitude distributions approximate an exponential relationship suggestive of a characteristic length scale of failure we interpret this lfe activity to represent quasi continuous slip on the deep extent of the alpine fault with lfes highlighting asperities within an otherwise steadily creeping region of the fault

chemical and isotopic variations in the wiśniowka mala mine pit water holy cross mountains south central poland in 2005 and 2006 hydrogeochemical study was carried out in the bipartite wi niowka mala pit lake of the holy cross mountains south central poland this is the largest acidic water body in poland this report presents the element concentrations in the water and sediment stable sulfur and oxygen isotope ratios in the soluble sulfates and stable oxygen isotope ratio in the water the scope of the investigation also encompassed mineralogical examinations scanning electron microscope x ray diffraction of the sediment the results of this study show that there is a spatial and temporal variability in concentrations of most elements and sulfur isotope ratios in the examined pit lake the water of the western pond displayed a lower ph with a mean of 3 73 and higher conductivity 390 s cm 1 as well as higher concentrations of sulfates 156 mg l 1 and most of the cations and anions the concentrations of fe2 and fe3 averaged 0 8 and 0 4 mg l 1 in contrast the eastern pond water revealed a higher ph mean of 4 36 lower conductivity 293 s cm 1 and lower sulfate 90 mg l 1 and trace metal levels similar variations were recorded in the stable sulfur isotope ratios the 34sv cdt so42 values in the water of the western pit pond were in the range of 6 7 to 4 6 mean of 5 6 whereas that in the eastern pit pond ranged from 2 2 to 0 9 1 6 the alkalinity of the entire lake water was below 0 1 mg l 1 caco3 no distinct difference in the 18ov smow so42 was noted between the western and eastern pit ponds compared to the purple pond in the sudetes poland and similar sites throughout the world the examined pit lake is highlighted by distinctly low concentrations of sulfates iron and other trace metals based on this and other studies performed in the holy cross mountains a conclusion can be drawn that the so42 in the wi niowka mala pit lake water is a mixture of so42 derived from the following sources 1 pyrite oxidation especially in the western pond water 2 leaching of soluble sulfates from soils and waste material as well as 3 subordinate deposition of airborne sulfate precipitation

geochemistry and stable isotope composition of the berkeley pit lake and surrounding mine waters butte montana abstract samples of mine water from butte montana were collected for paired geochemical and stable isotopic analysis the samples included two sets of depth profiles from the acidic berkeley pit lake deep groundwater from several mine shafts in the adjacent flooded underground mine workings and the acidic horseshoe bend spring beginning in july 2000 the spring was a major surface water input into the berkeley pit lake vertical trends in major ions and heavy metals in the pit lake show major changes across a chemocline at 10 20 m depth the chemocline most likely represents the boundary between pre 2000 and post 2000 lake water with lower salinity modified horseshoe bend spring water on top of higher salinity lake water below based on stable isotope results the deep pit lake has lost approximately 12 of its initial water to evaporation while the shallow lake is up to 25 evaporated the stable isotopic composition of so 4 in the pit lake is similar to that of horseshoe bend spring but differs markedly from so 4 in the surrounding flooded mine shafts the latter is heavier in both 34 s and 18 o which may be due to dissolution of hypogene so 4 minerals anhydrite gypsum barite in the ore deposit the isotopic and geochemical evidence suggests that much of the so 4 and dissolved heavy metals in the deep berkeley pit lake were generated in situ either by leaching of soluble salts from the weathered pit walls as the lake waters rose or by subaqueous oxidation of pyrite on the submerged mine walls by dissolved fe iii laboratory experiments were performed to contrast the isotopic composition of so 4 formed by aerobic leaching of weathered wallrock vs so 4 from anaerobic pyrite oxidation the results suggest that both processes were likely important in the evolution of the berkeley pit lake

assessing the impact of serwis mine tailings site on farmers wells using element and isotope signatures holy cross mountains south central poland this paper presents the results of a geochemical and isotopic study of technogenic soils and acid pool waters in the abandoned mine tailings pile and its potential impact on the adjacent farmers wells at the village of serwis south central poland the acid tailings pools showed strong trace element and ree signals these acid pools were featured by the predominance of medium rare earth elements mree with a strong positive gd anomaly the technogenic soils also revealed a mree roof shaped pattern but with distinct positive excursions in gd sm eu and ce the 34s so42 signatures of acid pool waters mean of 1 3 were close to those of soils and pyrite means of 2 3 and 3 2 respectively the waters of four farmers wells exhibited nearly the same 34s so42 values 0 7 4 0 as the nearby acid pool waters 0 3 3 1 the similar 34s isotope signatures combined with the highest contents of dissolved so42 181 577 mg l in these wells suggest that the tailings pile is a potential source of so42 derived from pyrite weathering this relationship may also be evidenced by a spatial site variable dendrogram that groups these four wells into one cluster at the linkage distance dlink dmax 100 53

geochemical processes in a highly acidic pit lake of the iberian pyrite belt sw spain abstract compared with pit lakes originated by coal mining little is known about in lake neutralization processes in pit lakes from sulfide ore mining in hard rock substrates which are typically very deep and acidic and receive low carbon c inputs and groundwater flows physicochemical processes in water and sediments from a pit lake san telmo 130 m deep in the iberian pyrite belt were investigated san telmo is a meromictic and highly acidic ph 2 8 pit lake due to ph buffering by precipitation of fe iii minerals schwertmannite and jarosite the sediments have a low abundance of c below 0 60 and iron minerals below 0 12 compared to most coal mining pit lakes in san telmo sediments iron reduction and sulfide oxidation may be thermodynamically favored due to low ph values in pore waters below 3 8 and the presence of reactive iron although schwertmannite is the main ferric mineral precipitating in the water column mineralogical analyses reveal a low abundance of schwertmannite in the sediment this may be due to the preferential use of this mineral in reduction reactions mediated by bacteria together with a low replenishment rate of the schwertmannite pool in the sediment the transformation of reactive iron schwertmannite and jarosite into goethite may limit sulfate reduction promoting acidic conditions in the sediment as long as the acid mine drainage continues to discharge into the lake the ph buffering exerted by ferric minerals in the sediments will limit the neutralization of the ph by sulfate reduction

the hydrogen and oxygen isotopic composition of precipitation evaporated mine water and river water in montana usa summary the isotopic composition of 42 samples of rain and snow collected in 2004 were used to construct a local meteoric water line lmwl for butte montana the derived equation d 7 31 18 o 7 5 r 2 0 987 represents one of the first published lmwls based on direct precipitation for any location in the northern rocky mountains samples of underground and surface mine waters in butte including the berkeley pit lake and a nearby tailings pond define a linear trend with a much lower slope and intercept than the lmwl d 5 00 18 o 49 5 r 2 0 991 consistent with non equilibrium evaporation at an average relative humidity of roughly 65 detailed evaporation calculations are presented which indicate that the shallow berkeley pit lake was approximately 25 evaporated in october 2003 whereas the surface of the tailings pond was at least 50 evaporated the intersection of the lmwl and mine water evaporation trend was used to calculate the average composition of recharge water to the flooded mine complex d 139 18 o 18 0 these values are considerably lighter than the weighted total of precipitation for the 2004 calendar year d 118 18 o 15 3 which is partly explained by the unusually low snowfall that montana experienced in 2004 based on this study the lmwl recently proposed by kendall and coplen 2001 kendall c coplen t b 2001 distribution of oxygen 18 and deuterium in river waters across the united states hydrological processes 15 1363 1393 from regression of isotopic data from a number of montana rivers is more accurately interpreted as an evaporation line isotopic trends based on river data should be treated with caution particularly in a semi arid region such as montana where rivers are often influenced by dams and irrigation withdrawals

precise tremor source locations and amplitude variations along the lower crustal central san andreas fault 1 we precisely locate 88 tremor families along the central san andreas fault using a 3d velocity model and numerous p and s wave arrival times estimated from seismogram stacks of up to 400 events per tremor family maximum tremor amplitudes vary along the fault by at least a factor of 7 with by far the strongest sources along a 25 km section of the fault southeast of parkfield we also identify many weaker tremor families which have largely escaped prior detection together these sources extend 150 km along the fault beneath creeping transitional and locked sections of the upper crustal fault depths are mostly between 18 and 28 km in the lower crust epicenters are concentrated within 3 km of the surface trace implying a nearly vertical fault a prominent gap in detectible activity is located directly beneath the region of maximum slip in the 2004 magnitude 6 0 parkfield earthquake

geochemistry water balance and stable isotopes of a clean pit lake at an abandoned tungsten mine montana usa abstract the calvert mine is a small tungsten rich scheelite skarn deposit in a remote mountainous region of southwest montana usa the open pit mine closed in the 1970s and subsequently flooded to form a pit lake that is roughly conical in shape 30 m deep and 120 m in diameter with no surface inlet or outlet the lake is holomictic with a groundwater flow through hydrology and an estimated residence time of 2 5 5 y water isotopes show that the lake is at an approximate steady state with respect to water balance and has experienced 30 evaporation the lake has a near neutral ph exceptional clarity and extremely low concentrations of nutrients sulfate and most metals including tungsten manganese concentrations are slightly elevated and increase with depth towards the sediment water interface despite seasonally anoxic conditions in the deep water dissolved fe concentrations are orders of magnitude lower than mn suggesting that insufficient organic carbon is present in the sediment of this oligotrophic lake to drive bacterial fe reduction based on stable isotope fingerprinting diffuse seepage that enters a nearby headwater stream at the base of a large waste rock pile can be directly linked to the partially evaporated pit lake however this seepage has neutral ph and low metal concentrations and poses no threats to the environment stable isotopes of dissolved inorganic carbon dic and dissolved oxygen do are used to track the relative importance of photosynthesis and respiration with depth in summer a zone of high productivity exists near the base of the chemocline releasing do that is isotopically light respiration exceeds photosynthesis below the secchi depth which causes do concentrations to approach zero towards the bottom of the lake in winter thick ice and snow cover prohibits photosynthesis however because of the low nutrient content most of the volume of the lake remains oxic through the winter overall the calvert lake is a good example of a pit lake formed from metal mining that has excellent water quality which is a result of its favorable geology paucity of sulfide minerals and hydrology flow through lake with short residence time in a temperate climate

investigating the characteristics of mine water in a subsea mine using groundwater geochemistry and stable isotopes investigation were conducted in the xinli subsea mine from 2006 to 2011 which is the largest subsea mine in china and threatened by the overlying quaternary aquifer and seawater hydrochemical and stable isotopic 2h and 18o analyses were used to study the relationships between various waters hydrochemical results indicated that the seepage water in the mine tunnels had higher ec tds and concentrations of most elements than the seawater and saline groundwater water analyses indicated the mine discharge was a mixture of the seawater brine and atmospheric precipitation the proportions of the three different sources were calculated based on hydrochemical and isotopic analyses the seepage water were more isotopically enriched than the seawater but less than the brine in addition the isotope mixing calculation indicated that the average proportions of mine water from seawater brine and atmospheric precipitation were about 38 5 46 and 15 5 respectively for the entire mine in 2006 however the concentrations of these analyses decreased and the proportion of the seawater increased 21 1 after 5 years of exploitation in 2011 these changes demonstrated that the surrounding rock mass underwent a certain extent of deformation and failure because of the mining disturbance which enhanced the permeability of the surrounding rock mass

deep tremor in new zealand triggered by the 2010 mw8 8 chile earthquake 1 deep non volcanic tremor nvt is usually associated with episodic slow slip events new zealand is one notable exception where numerous slow slip events have been identified yet nvt has remained undetected here we present the first known case of triggered nvt at new zealand s hikurangi subduction margin following the mw8 8 chilean earthquake of february 27 2010 we identify coherent high frequency tremor signals that are in phase with and modulated by the passing rayleigh waves this is consistent with the surface wave triggering potential for strike normal incidence on a low angle thrust fault after constraining the tremor depth on the plate interface we locate the tremor source within 20 km of the source area of episodic slow slip the tremor location is also near the edge of a region with high seismic attenuation that marks the boundary between dehydrated subducted slab and inferred hydrated underplated sediment we speculate that reduced interface friction and high fluid pressures provided by fluid rich underplated sediment facilitates the tremor generation

an experimental study of water rock interaction and acid rock drainage in the butte mining district montana this paper summarizes a laboratory study of water rock interaction and the generation of acidic mine drainage in the butte mining district montana the butte district includes two large open pit mines exploiting different portions of the same porphyry cu mo system 1 the well known berkeley pit which is abandoned and flooding with acidic mine water and 2 the nearby continental pit which is active the two pits are separated by a normal fault with several thousand feet of vertical displacement and consequently the styles of alteration and mineralization are quite different humidity cell and recirculating leachate experiments of crushed rock exposed on the walls of the berkeley pit produced effluent waters very similar in composition to the flooded berkeley pit lake in contrast the same experiments on crushed ore from the continental pit generated circum neutral leachates with low metal concentrations caused by the presence of calcite in the alteration assemblage because carbonate is being depleted at a faster rate than pyrite during weathering the quality of mine drainage in the continental pit could eventually degrade

geochemistry and stable sulfur and oxygen isotope ratios of the podwiśniowka pit pond water generated by acid mine drainage holy cross mountains south central poland abstract the paper presents the results of a geochemical and isotopic study of acidic pond water in the abandoned podwi niowka quarry poland the scope of investigations also encompassed mineralogical and isotopic studies of pyrite and related supergene minerals compared to similar sites throughout the world the pit pond water examined is characterized by a very low ph averaging 2 64 0 33 and simultaneously very low concentrations of so 4 2 geometric mean of 237 57 mg l 1 fe ii 4 8 3 4 mg l 1 fe iii 10 0 6 2 mg l 1 and other trace elements this acidity has been generated by complex processes of as rich pyrite oxidation combined primarily with hydrolysis precipitation and transformation of fe oxyhydroxysulfates and oxyhydroxides into goethite the specific mineralogy of ore and gangue minerals but especially the lack of acid buffering constituents has additionally contributed to the very low ph and element concentrations of the toxic elements the high content of as 1111 1879 mg kg 1 in the western part of pit pond sediment may be of great concern especially when using lime as a neutralizing agent of the acidic water the 34s of soluble so4 varied from 19 8 to 11 1 and was different from that of efflorescent sulfates 25 7 to 25 4 and host pyrite 25 4 2 5 the comparison of the 18o so 4 2 2 0 1 2 and 18o h2o 6 2 3 5 values indicated that the pyrite underwent bacterially catalyzed oxidation by two natural oxidants primarily by fe3 and to a lesser extent o2

geochemical modeling approach to predicting arsenic concentrations in a mine pit lake abstract between 1968 and 1983 the north pit at the getchell mine humboldt county nv filled with water to form a lake in 1983 water quality data were collected with the following results as concentrations of 0 29 to 0 59 mg l ph of 7 1 to 7 9 so 4 concentrations of 1490 to 1640 mg l and tds of 2394 to 2500 mg l using geochemical modeling techniques presented here pit lake waters have been theoretically allowed to react for 8 5 a the approximate time that the north pit had been completely full by 1983 modeling results predict ph of 7 9 to 8 2 so 4 concentrations of 1503 to 1644 mg l tds of 2054 to 2366 mg l and as concentrations ranging from 0 57 in the hypolimnion to 96 mg l in the epilimnion in the epilimnion model results do not match observed as concentrations suggesting that mechanisms such as precipitation of arsenate salts or adsorption to mineral surfaces may control as levels in an actual pit lake system adsorption to fe oxyhydroxide surfaces is questioned by the authors because of the low fe content in the getchell system but adsorption to al oh 3 gibbsite and clay mineral surfaces may be important in controlling natural as concentrations