a study on the regulation of the concentrations of some trace metals rb sr zn pb cu v cr ni mn and mo in saanich inlet sediments british columbia canada abstract bulk metal concentrations were measured in the sediments of saanich inlet in an attempt to establish the occurrence of trace metal enrichment in the anoxic central basin ba ni v cr zn pb cu and mo were found to be enriched in the anoxic ooze over the possible contributions from lithogenic sources spatial and seasonal variations in the chemical composition of the settling particulates collected with interceptor traps gave further indications of the mode of incorporation of these metals biogenic ba and cr appeared to be associated with opaline silica although alternative explanations are also possible particularly for ba zinc seemed to be added to the sediment essentially in association with planktonic materials while cu required an additional source directly linked to the anoxic environment similarly ni v and mo were added to the anoxic sediments by reactions occurring at the sediment water interface in the nearshore environment studied here these metals particularly ni and mo were not associated to any significant extent with planktonic materials of all the elements analyzed mo showed the largest enrichment in the anoxic sediments of saanich inlet

spatial analysis of soil hydraulic conductivity in a tropical rain forest catchment the topography of first order catchments in a region of western amazonia was found to exhibit distinctive recurrent features a steep straight lower side slope a flat or nearly flat terrace at an intermediate elevation between valley floor and interfluve and an upper side slope connecting interfluve and intermediate terrace a detailed survey of soil saturated hydraulic conductivity ksat depth relationships involving 740 undisturbed soil cores was conducted in a 0 75 ha first order catchment the sampling approach was stratified with respect to the above slope units exploratory data analysis suggested fourth root transformation of batches from the 0 0 1 m depth interval log transformation of batches from the subsequent 0 1 m depth increments and the use of robust estimators of location and scale the ksat of the steep lower side slope decreased from 46 to 0 1 mm h over the overall sampling depth of 0 4 m the corresponding decrease was from 46 to 0 1 mm h on the intermediate terrace from 335 to 0 01 mm h on the upper side slope and from 550 to 0 015 mm h on the interfluve a depthwise comparison of these slope units led to the formulation of several hypotheses concerning the link between ksat and topography

hydrogeochemical processes in an arid region of europe almeria se spain abstract in the lower andarax river basin 3 aquifer units have been defined namely the carbonate aquifer the deep aquifer and the detrital aquifer which between them contain a wide variety of water types identification of hydrogeochemical processes has been performed by studying a series of ionic ratios comprising the principal constituents together with b and li cl vs so4 cl vs mg cl vs li b vs li among the processes detected the circulation of groundwaters with high concentrations of so4 was found to have significant effects moreover in the coastal region naturally occurring processes related to the flushing of saline waters from sediments of marine origin occur in conjunction with others clearly of human origin that are related to saltwater intrusion a further factor is the entry from overlying deposits of waters with a high saline content this salinity is related to the flushing of sediments of marine origin the use of b and li together enables waters in which salinity is related to seawater to be distinguished from others in which salinity is related to evaporitic layers or to thermal areas the concentration of li is directly related to water temperature while that of b is greater in the most saline sectors of gypsiferous and or seawater origin

soil pipe distribution and hydrological functioning within the humid tropics a synthesis some of the most responsive runoff systems in the world are found within the humid tropics these runoff responses are likely to be affected by the presence of natural pipes within the soil this study provides a synthesis of the hydrological aspects of these phenomena within the humid tropics of the studies reporting the presence of soil piping within the humid tropics most are associated with ultisol soils and locally most pipe outlets are observed on the lower sections of hillslopes while the drainage role of pipes has been observed providing faster and slower components of stream hydrographs the mechanism of their recharge remains less clear in part this is because their spatial extent is poorly mapped within the hillslopes of the humid tropics further studies quantifying the length and recharge of soil pipe networks within the humid tropics are needed

field experiments in a fractured clay till 1 hydraulic conductivity and fracture aperture field values of horizontal hydraulic conductivity measured in the upper 1 5 5 5 m of a weathered and fractured clay rich till were strongly influenced by smearing around piezometer intakes which occurs during augering and by the physical scale of the measuring device values measured in conventional augered piezometers were typically 1 2 orders of magnitude lower than those measured in piezometers designed to reduce smearing measurements of hydraulic conductivity in small scale seepage collectors or piezometers which typically intersect fewer than 10 fractures vary over a much greater range 10 10 to 10 6 m s than large scale values based on infiltration into 5 5 m deep trenches which intersect thousands of fractures range 10 7 to 3 10 7 m s values of hydraulic fracture aperture 1 43 m and fracture porosity 3 10 5 to 2 10 3 were calculated using the cubic law with fracture orientation distribution measurements and the small scale hydraulic conductivity measurements this paper provides the first reliable determination of the magnitude and spatial distribution of hydraulically derived fracture parameters in a clay deposit the absence of such data has until now severely limited the application of quantitative groundwater flow and contaminant transport models in this type of deposit

hillslope hydrology in tropical rainforest steeplands in brunei many remaining areas of tropical rainforest in south east asia are located on landscapes dominated by deep valleys and very steep slopes now that logging activities are extending into these steeplands it is essential to understand how the natural rainforest system behaves if any kind of realistic assessment of the effects of such disturbance is to be made this paper examines the hydrological behaviour of an undisturbed rainforest system on steep topography in the temburong district of brunei north west borneo the physical and hydrological properties of the regolith material are generally typical of tropical residual soils the regolith has a clay texture and a low dry bulk density beneath a superficial litter organic horizon the infiltration capacity of the surface soil was several hundred mm h 1 that of the exposed mineral subsoil was an order of magnitude less similar to the saturated hydraulic conductivity ksat of around 180 mm h 1 at a depth of 150 cm there was no indication that ksat reduced with depth except very near the bedrock interface soil tensions were measured using a two dimensional array of tensiometers on a 30 slope during dry season conditions infiltrating rain water contributes to soil moisture and drying of the soil is dominated by transpiration losses during wet season conditions perched water tables quickly develop during heavy rainfall giving rise to the rapid production of return flow in ephemeral channels no infiltration excess or saturation overland flow was observed on hillslopes away from channel margins subsurface storm flow combined with return flow produce stream flow hydrographs with high peak discharges and very short lag times storm event runoff coefficients are estimated to be as high as 40 it is concluded that the most distinctive feature of the hydrology of this steepland rainforest is the extremely flashy nature of the catchment runoff regime produced by the combination of thin but very permeable regolith on steep slopes copyright 2000 john wiley sons ltd

hydrological effects and nutrient losses of forest plantation establishment on tropical rainforest land in sabah malaysia abstract new measurements of field saturated hydraulic conductivity soil moisture rain intensity surface runoff and erosion are presented with earlier published data on soil physical properties stream water quality and runoff and dissolved nutrient losses from a paired catchment experiment in sabah malaysia the catchment experiment compared crawler tractor extraction and burning normal practice catchment w5 versus manual extraction and no burning w4 another catchment where secondary vegetation after forest fire was cleared and burned before planting was also studied w1 2 two separate control catchments were also included one was for rainforest w6 and the other comprised secondary vegetation w3 although hydraulic conductivity was reduced in clay soils at 20 and 40 cm depths under tractor tracks the decrease was less drastic than for steady state infiltrability on both clay and sand topsoils since control topsoils 0 20 cm were well aggregated in contrast to more compact subsoils with higher clay content topsoils were close to saturation at all times also after treatments but control forest surface runoff in slopes excluding valley bottom comprised only 2 9 of rainfall in a wet year except for just after burning clear felling did not increase slope surface runoff on undisturbed clay topsoils and surface erosion was not increased except for the erosion of ash after burning on tractor tracks extensive surface runoff caused surface and gully erosion elevated concentrations of suspended sediment in stormflow in w5 were back to pretreatment levels within 2 years under manual extraction suspended particulate loss was approximately half most of which emanated from sediments activated by increasing stream runoff dissolved nutrient losses from catchment w5 in kilograms per hectare were 39 9 n 1 3 p 189 k 27 ca and 16 mg in the 33 months during and after treatments these amounts were equivalent to between 10 and 185 of the removal in the harvest for the minimum disturbance of w4 the increased nutrient loss was halved except for ca burning of residues in w1 2 and w5 increased dissolved losses dramatically over a short period the bulk of soil water was concluded to move quickly as troughflow in topsoil hence bypassing of retention possibilities in the largest pores with small specific surfaces led to large dissolved nutrient stream losses in this humid tropical environment even without soil disturbance and extensive surface runoff

characterization of portuguese thermo mineral waters to be applied in peloids maturation portugal has an old tradition of using thermo mineral waters for thermal treatments near mineral water springs traditional applications are made using clays mixed with mineral waters gushing up in situ which are employed for the treatment of skin and musculoskeletal disorders our research team has found that some of the studied portuguese clays and similar formations have compositional and physico chemical properties that partially explain their therapeutic qualities in what concerns portuguese mineral waters only a few studies were made trying to characterize and better understand their beneficial effects on human health when mixed with clays in fact the therapeutic efficiency of the obtained thermal products depends on the geochemistry of the mixed clay mineral water peloid in this study a total of 28 thermo mineral water samples were collected from springs boreholes located at portuguese spas or traditional healing baths the aim of this study was the geochemical characterization of collected water samples in order to select the most suitable thermo mineral water samples reduce the lack of information about the trace hazardous elements and also contribute towards the revitalization of portuguese thermalism results show a large range of chemical characteristics and diverse water types temperature electrical conductivity and ph values are variable among samples different hydrochemical water types were obtained from hill piper diagrams in terms of potential application for maturation we selected three ca so4 t1 h1 and h2 and two na hco3 t14 and t15 water samples as best candidates to produce desirable therapeutic effects on peloids

sediment production from forest road surfaces erosion on roads is an important source of fine grained sediment in streams draining logged basins of the pacific northwest runoff rates and sediment concentrations from 10 road segments subject to a variety of traffic levels were monitored to produce sediment rating curves and unit hydrographs for different use levels and types of surfaces these relationships are combined with a continuous rainfall record to calculate mean annual sediment yields from road segments of each use level a heavily used road segment in the field area contributes 130 times as much sediment as an abandoned road a paved road segment along which cut slopes and ditches are the only sources of sediment yields less than 1 as much sediment as a heavily used road with a gravel surface

persistence of road runoff generation in a logged catchment in peninsular malaysia measurements of saturated hydraulic conductivity ks and diagnostic model simulations show that all types of logging road trail in the 14 4 ha bukit threk experimental catchment 3 btec3 generate substantial horton overland flow hof during most storms regardless of design and level of trafficking near surface ks 0 0 05 m on the main logging road skid trails and newly constructed logging terraces was less than 1 2 and 34 min h 1 respectively near surface ks on an abandoned skid trail in an adjacent basin was higher 62 mm h 1 owing to the development of a thin organic rich layer on the running surface over the past 40 years saturated hydraulic conductivity measured at 0 25 m below the surface of all roads was not different all 6 mm h 1 and corresponded to the ks of the adjacent hillslope subsoil as most roads were excavated into the regolith more than 0 5 1 m after 40 years only limited recovery in near surface ks occurred on the abandoned skid trail this road generated hof after the storage capacity of the upper near surface layer was exceeded during events larger than about 20 mm thus excavation into low ks substrate had a greater influence on the persistence of surface runoff production than did surface compaction by machinery during construction and subsequent use during logging operations overland flow on btec3 roads was also augmented by the interception of shallow subsurface flow traveling along the soil saprolite bedrock interface and return flow emerging from the cutbank through shallow biogenic pipes the most feasible strategy for reducing long term road related impacts in btec3 is limiting the depth of excavation and designing a more efficient road network including minimizing the length and connectivity of roads and skid trails copyright 2007 john wiley sons ltd

geochemistry of sediments from the mangalore cochin shelf and upper slope off southwest india geological and environmental factors controlling dispersal of elements abstract the geochemical investigations on 136 surficial sediment samples of the mangalore cochin shelf and upper slope were undertaken to understand the distribution sources and processes by which various major and trace elements are incorporated into the sediments texturally the inner shelf 120 m water depth are dominantly composed of clayey sediments whereas the outer shelf 50 120 m water depth is carpeted by relict 10 000 yr in age sands the results show that sediment texture largely controls the distribution of elements the sandy relict sediments of the outer shelf 59 samples and of the upper slope restricted coverage have high contents of sio 2 caco 3 and sr amongst which sio 2 is present as terrigenous quartz sand while caco 3 and sr being well correlated with skeletal components are biogenous extremely good positive correlation between sr and caco 3 r 0 77 suggests presence of sr in the lattices of aragonite which is the main carbonate mineral the clay rich sediments of the inner shelf 52 samples and upper slope 25 samples are both very rich in organic carbon content and low in sio 2 content and very high in al 2 o 3 tio 2 fe 2 o 3 mgo na 2 o k 2 o p 2 o 5 mn cu ni zn and li contents as compared to the sandy sediments of the outer shelf except for organic carbon p 2 o 5 and tio 2 strong positive correlations of these components with al 2 o 3 r 0 41 0 90 suggest their association mainly with clay minerals within the clay minerals these are present in the crystal lattice either as essential constituent or incorporated by cation exchange or adsorbed onto clay platelets organic carbon p 2 o 5 and tio 2 also show positive correlation with al 2 o 3 mainly due to their physical association with fine grained clayey sediments phosphate in these sediments is mainly present in association with organic matter and to some extent it also occurs either as ferric phosphate or as authigenic apatite in general the geochemistry of these sediments clearly reflects their mineralogy formation of fe and mn hydroxides in the nearshore regions is responsible for scavenging of ni cu and zn and effectively incorporating them into the inner shelf sediments these trace elements also show significant correlation with organic carbon r 0 51 0 56 suggesting that a part of their content is biogenous

hydrogeochemical analysis of salinization processes in the coastal aquifer of oropesa castellon spain the coastal aquifer of oropesa is affected by salinization processes undoubtedly associated with intense groundwater exploitation for agriculture supply the aquifer corresponds geologically to a tectonic depression with plioquaternary fill hydrogeologically this aquifer is detrital with intergranular porosity which receives substantial recharge from adjacent mesozoic aquifers contact with the sea in addition to the presence of cultivated soil requiring extreme exploitation of groundwater frequently give rise to processes of seawater intrusion the present research is an attempt to understand the saltwater intrusion in this aquifer using hydrochemical analyses of the behavior of certain minor ions that could help in the characterization process in the case of the oropesa sector groundwater salinization does not appear to be attributable solely to the intrusion of seawater but there are also anomalies related largely to the geology of the sector and its surroundings the type of recharge the hydrodynamic conditions in the specific area etc

investigation of high pressure selective adsorption desorption behaviour of co2 and ch4 on coals an experimental study while an increasing amount of data is becoming available on the sorption capacity of natural coals for pure ch4 and co2 at different temperatures and pressure ranges only few measurements have been reported for mixtures of two or more gas components under the conditions of competitive sorption high pressure adsorption desorption experiments with co2 ch4 gas mixtures have been carried out on 10 coals of different rank and composition to investigate their selectivity with respect to the sorption of the two gases the sample set comprised two coals from the netherlands ranging in vitrinite reflectance from 1 19 to 1 56 vrr three coals from the silesian basin in poland vrr 0 68 to 0 78 and five coals from the argonne premium coal sample programme vrr 0 25 to 1 68 the experiments were performed in the dry and moisture equilibrated state in addition the effect of grain size on the competitive sorption was examined the results are reported as a guideline for predicting adequate coal properties with respect to co2 injection and co2 enhanced coal bed methane ecbm projects in the future the volumetric sorption experiments were performed with a sequential arrangement of calibrated reference and measuring cells and a sample loop for transfer of gas samples to an on line gas chromatograph the experiments were carried out at 45 c and pressures up to 23 mpa only few measurements showed preferential adsorption of co2 and preferential desorption of ch4 as commonly expected distinct variations were observed in the competitive adsorption and desorption behaviour of the different dry and moist samples ranging from preferential adsorption of ch4 in the low pressure range to preferential desorption of co2 over the entire pressure range the observed preferential sorption phenomena give rise to the assumption that co2 sequestration in coal seams with subsequent co2 enhanced cbm production might only be an option in specific coal basins

behaviour of thermal waters through granite rocks based on residence time and inorganic pattern summary thermal waters are certainly a substantial asset of the galicia region of spain they can be regarded as worth developing because of their human health implications and if thermal tourism is promoted their importance to the local economy in this paper the chemistry of major and trace inorganic elements in about 45 thermal springs and wells discharging in the same hydrographical system are presented and discussed for handling the results of all measurements graphical representations of b li vs so 4 2 cl ratios hill piper diagram discriminant analysis da and principal component analysis pca were employed all this with the intention to classify based on their inorganic pattern both thermal springs and wells waters but also waters circulating through adamellite and granodiorite rocks the results of the hydrogeochemistry analysis showed three main water families sulphated chlorinated and bicarbonated waters the results show also the presence of saline materials with chloride influence in the deeper aquifer allowing its classification in deeper and younger shallow waters

sources of suspended sediment within a tropical catchment recovering from selective logging quantification of the source of suspended sediments generated by selective forestry activities is central to the development of sustainable forestry guidelines this assessment is hampered by a dearth of available studies particularly from the tropics this study involved the monitoring at 10 s intervals of surface discharge and turbidity from 15 contributory areas of a 44 ha catchment the catchment is located within lowland dipterocarp rain forest on borneo island in a region recovering from the first episode of selective timber removal that took place some 5 years previously both the within storm dynamics of the sediment flux and the time integrated sediment yields were analysed to link the source landforms to the catchment behaviour a 10 year rainfall event of 167 mm occurred during the monitoring period and triggered a debris slide and several log culvert collapses along the area s main timber haulage road the sampling design captured this event s dynamics and allowed lumped catchment response to be traced to the new landforms during the 1 day period of the 10 year event some 33 t of suspended sediment were transported from one debris slide comprising a significant proportion of the 105 t discharging from the whole catchment which itself constituted 40 of the annual yield of 592 t km 2 the contributory areas with only ephemeral waterflows including former haulage roads and tracks generated relatively little sediment during this 10 year event or in other storms this work suggests that though some sediment sources recover from the impacts of forest road construction and harvesting collapse of roadfill materials or more local log culvert failure persists for several years after harvesting sustainable forestry guidelines that do not focus on ameliorating these persistent instabilities may not significantly mitigate the geomorphic impacts of conventional selective harvesting copyright 2004 john wiley sons ltd

mineralogy of the carbonate sediments western continental shelf of india abstract an x ray diffraction study of forty six sediment samples and three oolitic limestone samples from the western continental shelf of india shows that aragonite is the dominant carbonate mineral 99 maximum followed by low magnesium calcite 77 maximum and high magnesium calcite 39 maximum mgco 3 in the high magnesium calcite ranges from 5 to 21 maximum in the limestone with the most prominent mode at 13 followed by lesser modes at 16 9 and 6 5 these modes are attributed to the presence of various organic constituents in the sediments and rocks the sediments and the limestones are similar in mineralogy thus we conclude that no diagenetic change has taken place in the limestones after their formation

inferring flow types from dye patterns in macroporous soils in this study we exploit dye patterns to identify flow types in macroporous soils as a step forward from using dye patterns simply as qualitative pictures that illustrate preferential flow dye tracer experiments at different irrigation rates and initial soil moisture conditions were carried out on three hillslope sites several vertical and horizontal soil sections were prepared after each experiment to analyze the patterns of the dye tracer brilliant blue fcf photographs of the soil sections were processed by image analysis to discriminate between stained and unstained areas and to classify stained areas into three classes of dye concentration the images of the vertical sections were first analyzed according to conventional approaches e g dye coverage then a new approach was developed using the extent and distribution of the stained objects to classify flow into five types two of these flow types occur only in the soil matrix and three of them are related to the degrees of water flow between macropores and soil matrix interaction from horizontal sections the macropore distribution was classified and in combination with the dye pattern the interaction quantified based on statistical description of the spatial relationship between macropores and stained areas categorized flow type profiles showed a logical sequence in each of our experiments and we think the concepts will have broad application in soil science and infiltration research to compare the infiltration regimes of soils

spatial variability of soil hydraulic conductivity along a tropical rainforest catena abstract we investigate the spatial variability of saturated hydraulic conductivity ksat along a tropical rainforest catena which consists of a typic kandiudult latossolo vermelho distrofico argissolico and plinthic hapludox latossolo amarelo distrofico tipico the former soil type extends from midslope to interfluve and has a high clay content throughout the profile whereas the latter soil type extends from the midslope to valley bottom and only has a high clay content at depths 90 cm we measured ksat along a transect at depths of 20 30 50 and 90 cm with a compact constant head permeameter ksat is not significantly different 0 10 between these soil types at any depth except for 90 cm ordinary and robust linear regression models with distance from the interfluve as in the independent variable showed no significant change in ksat as a function of topography loess regression showed some dependency of ksat on topography only at the 90 cm depth semivariograms showed no apparent spatial structure in ksat at distances 25 m for all depths we conclude that the strong topography dependence of soil types along this catena and hence primary soil attributes is not reflected in a similar dependence of ksat and tentatively attribute this lack of dependence to the overriding influence of bioturbation controlled macroporosity we outline a framework for detecting possible ksat topography relationships based on the distinction between bioturbation controlled nonstructural macroporosity and mineralogy controlled structural macroporosity

controls on methane sorption capacity of indian coals details of methane sorption properties of some indian coals ranging in rank from high volatile bituminous c 0 62 ro max to medium volatile bituminous coal 1 46 ro max were investigated to determine the major factors influencing gas adsorption capacity and desorption rate variables studied included moisture content mineral matter content rank and coal type maceral composition adsorption isotherm analysis of dry coals showed that adsorption capacity followed a second order polynomial trend with rank equilibrium moist samples showed a linear increase in adsorption capacity with rank and had a significantly reduced adsorption capacity compared to the dry coals with the reduction being related to the moisture content mineral matter acted as a simple diluent to the gas adsorption capacity of the coals and was found to be nonadsorbent adsorption capacity moist was reduced by 0 32 cm3 g 10 ft3 gas t for every 1 increase in the ash yield bright and dull coal lithotypes showed strong separation in their adsorption capacities on an as analyzed basis with the bright coals adsorbing greater quantities of gas on a dmmf basis however no relationship was observed between coal type and gas storage capacity comparison of maceral composition with adsorption capacity dry confirmed this observation effective diffusivity de of methane through the coal was seen to be affected by coal type and rank effective diffusivity de decreased as rank increased which is related to the increasing microporous nature of the coal bulk coals tested had 2 3 times larger effective diffusivities than bright coals and dull coals had intermediate rates the larger de values for the bulk coals may be related to the presence of collodetrinite coupled with mineral matter which acts as higher permeability pathways for the gas compared with the high ash dull coals dominated by inertinite macerals differences were noted with similar age permian australian coals where methane adsorption capacities were larger and coal type had a stronger influence on adsorption capacity begin page 202

effects of logging and fire on runoff and erosion on highly erodible granitic soils in tasmania a set of rainfall simulator experiments was carried out in a logged forest in tasmania australia to quantify the impact of logging and fire on runoff and soil loss a large portable rainfall simulator was developed for the experiments to help overcome problems associated with spatially varying hydraulic and erosion properties of the soil simulated rainfall events with intensities of approximately 35 75 and 150 mm h 1 were applied to four 300 m2 plots with different levels of surface disturbance severely burnt logged and burnt with high mechanical disturbance logged with low mechanical disturbance and undisturbed the experiments indicated that the amount of runoff and soil loss from the plots depended on the type and degree of disturbance to the natural biotic crust developed on this soil erodibility per unit runoff was greatest on the severely burnt plot but runoff on the mechanically disturbed site was so great that it produced the highest total sediment yield on an event basis runoff production was similar on the three plots where the natural biotic crust was largely intact and was low relative to the plot with high mechanical disturbance total sediment yield was typically higher on logged plots than on unlogged plots

impacts of logging disturbance on hillslope saturated hydraulic conductivity in a tropical forest in peninsular malaysia using a constant head permeameter we found an abrupt natural decrease in saturated hydraulic conductivity ks within the upper 1 0 m soil profile of an orthoxic tropudult at the bukit tarek experimental catchments research area in tropical peninsular malaysia the depth at which low ks could cause a perched water table in response to high intensity rainfall however was too great to generate saturation overland flow on planar hillslopes in the study area the effects of logging activity on ks at five subsurface depths 0 1 0 25 0 5 0 75 and 1 0 m on the non roaded portion of the harvest area were examined at the three following sites which differed in the degree of disturbance and recovery since timber harvesting 1 selective logging conducted in the 1960s 2 mechanized selective tree removal conducted 4 years ago and 3 high impact clear cutting just prior to measurement this recent logging greatly disturbed the soil surface via compaction topsoil subsoil mixing burning and produced comparatively high variability in near surface ks changes in ks at or below 0 25 m however were not detected with certainty at any sites in terms of hillslope hydrologic response the connectivity of zones of low ks in the harvest area with dense networks of skid trails and terraces was identified as one of the most important consequences of timber harvesting although this phenomenon was not quantified we estimate the recovery time for near surface ks on the non roaded hillslope to be less than 40 years d 2006 elsevier b v all rights reserved

geological controls on coalbed methane reservoir capacity and gas content the influence of coal composition and rank on coalbed methane reservoir capacity gas content and gas saturation have been investigated for a series of australian canadian and united states coals globally there is no or little correlation between coal rank and methane adsorption capacity as commonly assumed although in particular basins there are general trends with rank and composition micropore1 capacity and surface area determined from low pressure carbon dioxide adsorption isotherms 0 c decrease and then increase with rank passing through a minimum in the high volatile bituminous coal rank there is no consistent variation in modal micropore size or size distribution with rank for suites of isorank coals there is a poor permian bulli and wongawilli seams australia to good positive correlation gates formation coal seams lower cretaceous canada between vitrinite content and methane adsorption capacity dry ash free and as received bases for each isorank coal suite there is a good correlation between micropore capacity and abundance of vitrinite and high pressure methane adsorption capacity comparison of coals of similar composition but from different isorank suites indicates however that the coals with the highest methane adsorption capacity do not necessarily have the highest micropore capacity such results are counterintuitive most pore volume available for methane adsorption is generally assumed to be microporosity it is suspected that moisture prevents methane from accessing some microporosity or competes with methane for adsorption space carbon dioxide micropore capacity which is performed on a dry basis may thus not reflect the microporosity available for gas adsorption in moisture equilibrated coals alternatively because of differing physical and chemical properties of carbon dioxide and methane apparent microporosity available to carbon dioxide due to greater energy of adsorption may not be available to methane total desorbed gas from canister analyses of sydney basin australian coals suggests that most coals are under saturated for a small data set the degree of saturation is negatively correlated with permeability r 0 78 suggesting preferential gas leakage from the higher permeability coals which are vitrite rich some degree of under saturation is probably the result of increased reservoir capacity as a consequence of uplift of the coal seams and thus lower temperatures following gas generation rates of desorption are correlated with total gas content r 0 79 but do not correlate with rank or any compositional parameter

processes controlling forms of phosphorus in surficial sediments from the eastern arabian sea impinged by varying bottom water oxygenation conditions abstract the surficial sediments from the upper continental slope of the eastern arabian sea impinged by the oxygen minimum zone omz 150 1200 m water depth show varying concentrations of the biogenic element phosphorus p 0 1 0 2 in the northern and southern areas even though total organic carbon concentrations are relatively constant toc 2 5 prakash babu et al 1999 to understand this discordance 17 surface sediment samples from shelf slope and deep sea of the eastern arabian sea were investigated using a five step sequential extraction scheme to delineate the process responsible for p enrichment in omz high fractions of organic phosphorus porg 10 26 biogenic phosphorus pbio 36 48 relatively low molar corg porg ratios 322 447 and corg preactive ratios close to redfield ratio in omz sediments of the se arabian sea suggest accumulation under high surface production and low residence time of labile forms of p due to high sedimentation rates despite higher productivity in surface waters low fractions of porg 8 13 less than deep sea sediments of the study area 12 13 pbio 25 33 relatively high molar corg porg ratios 341 508 and corg preactive ratios less than redfield ratio in omz sediments from the ne arabian sea may indicate a higher degree of regeneration and diagenetic transformation of labile forms of p to other phases authigenic phosphorus paut fraction varies by a factor of 2 8 in sediments from the omz when compared to well oxygenated deep sea sediments of the study area while the ptotal remains constant significant p transformation seems to occur in ne arabian sea which is suggested by high paut fraction 50 compared to low paut fraction 10 39 in the se arabian sea sediments supply rates of phosphorus variable rates of p dissolution under varying dissolved oxygen contents in the bottom waters and early diagenetic transformation of p within the sediments seem to influence p geochemistry in sediments overlain by the omz in the eastern arabian sea

forest roads and geomorphic process interactions cascade range oregon a major flood in february 1996 triggered more than 100 geomorphic features affecting forest roads in a 181 km 2 study area in the western cascade range oregon eight types of features including mass movements and fluvial features were mapped measured and analysed using geographic information systems and sediment budgets for the road network although roads functioned as both production and depositional sites for mass movements and fluvial processes the net effect of roads was an increase in basin wide sediment production debris slides from mobilized road fills were the dominant process of sediment production from roads road related sedimentation features were concentrated in a portion of the study area that experienced a rain on snow event during the storm and was characterized by the oldest roads and steep slopes underlain by unstable highly weathered bedrock the downslope increase in frequency of features and volumes of sediment produced combined with the downslope increase in relative frequency of fluvial over mass wasting processes suggests that during an extreme storm event a road network may have major impacts on stream channels far removed from initiation sites overall this study indicated that the nature of geomorphic processes influenced by roads is strongly conditioned by road location and construction practices basin geology and storm characteristics published in 2001 by john wiley sons ltd

a critical evaluation of depositional parameters controlling the variability of organic carbon in arabian sea sediments abstract organic carbon distribution in the surficial sediments of the arabian sea to some extent mirrors the surface productivity being both high in the peripheral portions and low in the central region suggesting that the productivity is a primary source of organic matter however a critical examination reveals that the organic enrichment on the slope of the indian margin is two to four higher max 16 71 than on the slope of the arabian peninsula max 7 54 while the productivity in the former region is three to four times lower than the latter this observation suggests that the influence of productivity on organic enrichment is of secondary importance high concentrations 4 of organic carbon exactly coincide with the oxygen minimum zone 150 1500 m water depth evidently reflecting the crucial role played by the anoxic bottom waters in the preservation of organic carbon incidently the organic rich band along the western indian slope is wide long and highly concentrated as compared to that of the slope of the arabian peninsula and no organic enrichment is found on other continental slopes of the arabian sea although an equally intense oxygen minima impinge on the floor of the slope such a variability of organic carbon on the slopes is attributed to various geological parameters such as texture of sediments rates of fine terrigenous sediment deposition shelf width slope gradient bottom currents and adsorption capacity of individual clay minerals all these observations suggest that the productivity is not an ultimate control for the organic enrichment of bottom sediments but it is the bottom water anoxia in conjunction with various depositional parameters which determine the degree of preservation

clay sediment accumulation rates on the monsoon dominated western continental shelf and slope region of india abstract clay accumulation rates shown in sediment cores from the nearshore to outer continental shelf and slope regions in water depths of 10 1246 m on the western continental margins of india were determined by the 210 pb dating technique the 210 pb excess concentration encountered in these regions is about 3 5 dpm g and is independent of water depth the range of clay accumulation rates is from 1 8 to 19 mm yr for the shelf region and decreases southward from the tapti and narbada river confluence in the gulf of cambay this pattern indicates sediment dispersal in the coastal region regulated by southwest monsoon dominated littoral currents the same trend is encountered all along the southwestern traverse this suggests that suspended matter transport across the shelf is minimal since clay accumulation rates on the outer shelf are only 1 8 2 5 mm yr the clay accumulation rate in the slope region is 3 8 mm yr the high accumulation rates encountered on the upper continental slope may be attributed to the terrigenous influx of indus river sediment