the inversion wind pattern over west antarctica abstract the surface windfield over the gently sloping interior ice fields of antarctica is characterized by a high degree of persistence in terms of both direction and speed the forcing of the surface wind is due primarily to the radiational cooling of the air adjacent to the sloping terrain the representativeness of a simple diagnostic equation system in inferring the surface winds from a knowledge of terrain slope and temperature inversion structure is examined results suggest at least qualitatively accurate surface drainage patterns over the antarctic continent are possible using this technique a wintertime surface wind simulation for west antarctica has been generated based on an accurate ice topography map close agreement is seen between the simulated surface windfield with field observations and sastrugi orientations implications of the simulation are discussed

subaqueous paleoproterozoic metarhyolite dome flow cone complex flin flon greenstone belt manitoba canada abstract two sparsely plagioclase phyric rhyolite domes 50 100 m thick and 125 250 m long as observed in 2 dimensional vertically dipping exposures are partly mantled by a rhyolite volcaniclastic complex that on the south side of the domes also forms a half cone like mound at least 60 m thick and 500 m long the domes and mantling volcaniclastic complex are overlain by three aphyric to sparsely phyric rhyolite flows that are 70 120 m thick and 550 1200 m long domes and flows have a lower columnar jointed highly fractured locally brecciated subfacies that grades upward into 40 95 crackled and disaggregated breccia crackled breccia is a highly fractured subfacies in which clast like areas are bounded by closely spaced joints and minor matrix but there is only limited rotation of clasts crackled breccia was produced by quench fracturing combined with hydraulic action of water converted to steam or supercritical fluid within the fractures overlying disaggregated breccia comprises rotated particles and 25 50 matrix it is most abundant near flow margins and is a crumble breccia produced by flow advance or expansion the volcaniclastic mound comprises lenticular interlayered facies of 1 resedimented phreatomagmatically generated heterolithic rhyolitic tuff and lapilli tuff 2 isolated to close packed rhyolite lobes that are 0 5 5 m thick and 0 5 50 m long the lobes are at least in part pillows and 3 units comprising small

a case study of a ross ice shelf airstream event a new perspective abstract a case study illustrating cloud processes and other features associated with the ross ice shelf airstream ras in antarctica is presented the ras is a semipermanent low level wind regime primarily over the western ross ice shelf linked to the midlatitude circulation and formed from terrain induced and large scale forcing effects an integrated approach utilizes moderate resolution imaging spectroradiometer modis satellite imagery automatic weather station aws data and antarctic mesoscale prediction system amps forecast output to study the synoptic scale and mesoscale phenomena involved in cloud formation over the ross ice shelf during a ras event a synoptic scale cyclone offshore of marie byrd land draws moisture across west antarctica to the southern base of the ross ice shelf vertical lifting associated with flow around the queen maud mountains leads to cloud formation that extends across the ross ice shelf to the north the low level cloud has a warm signature in thermal infrare

origin of ree mineralization in the bastnas type fe ree cu mo bi au deposits bergslagen sweden the bastnas type deposits with mineral assemblages of fe oxides ca mg silicates rare earth element ree silicates ree fluorocarbonates and cu fe mo bi sulfides are associated with marble horizons in a strongly na k and or mg altered metavolcanic succession over a distance of at least 80 km in a sw ne trending zone in western bergslagen two subtypes occur 1 enriched relative to the other type in light ree lree and fe exemplified by the bastnas and rodbergsgruvan deposits and 2 enriched in heavy ree hree y mg ca and f represented by deposits in the norberg district bastnasite hosts primary fluid h2o co2 inclusions with salinities of 6 29 eq wt cacl2 and with total homogenization temperatures th tot of ca 300 400 c subtype 2 has late stage fluorite with fluid inclusions that show 1 16 eq wt nacl and th tot of ca 90 150 c molybdenite re os ages obtained from three deposits are 1 904 6 1 863 4 and 1 842 4 ma nd isotopic data from five different ree minerals yielded no defined isochron but a range in end 1 88 ga of 0 2 to 1 6 the oxygen isotope values 18osmow of dolomite and calcite from the associated ree mineralized skarn and recrystallized carbonate assemblages lie in the range 6 1 8 6 overlapping with those of the host marbles carbon isotope values 13cpdb show typical magmatic signatures of 6 7 to 4 4 while the host marbles group around ca 2 4 the sulfur isotope 34scdt values of associated sulfides range between 10 8 and 0 2 the combined evidence suggests ree mineralization beginning at 1 9 ga from mainly svecofennian juvenile magmatic 400 c fluids carrying si f cl s co2 and the ree in addition to other metals mineralization occurred through reactions with dolomitic layers in the supracrustal units coevally with regional metasomatic alteration associated with fluid circulation through an extensive active volcano plutonic complex

mesoscale cyclone activity over antarctica during 1991 2 near the antarctic peninsula a survey of mesoscale cyclogenesis near the antarctic peninsula has been carried out for 1991 based on digital satellite imagery collected at palmer station slightly higher cyclonic activity was found over the bellingshausen sea sector bss than in the weddell sea sector wss both sides were characterized by a pronounced formation maximum in summer and a minimum in winter comma clouds were the dominant vortex type and their average diameter was around 370 km trajectories show that many vortices in the bss move northeastward toward the drake passage with some of the most well developed moving north northeastward to the southern tip of south america bringing severe weather conditions to that area little systematic motion was noted over the wss the fraction of mesoscale cyclones with middle and or high cloud on the west side of the antarctic peninsula was much higher than on the east side these numerous and deep mesoscale cyclones are a consequence of the frequent outbreaks of cold air associated with synoptic scale cyclones that move cold air northward over the relatively warm bellingshausen sea with convective instability resulting this happens much less often in the wss where low level baroclinic instability and vortex stretching are the dominant formation mechanisms and air sea interaction is usually much less vigorous due to the stabilizing influence of the extended sea ice cover

the accretionary svecofennian orogen insight from the babel profiles abstract the babel profiles b c 1 7 form a 1200 km long nearly continuous cross section through the svecofennides the near vertical marine reflection profiles display a wide range of crustal structures that can be associated with both the accretionary svecofennian orogeny 1 96 1 75 ga and the following subjotnian and jotnian rift stages 1 65 1 11 ga the svecofennian accretionary orogeny took place when a number of micro plates with island arc affinities and surface expression of a large archipelago accreted to the continental karelian plate some of the accreting terranes seem to have had older cores that have acted as crustal indentors during the collision babel profiles 3 and 4 image a series of collisional terrane boundaries between karelian continental margin savo arc sa and central finland arc cfa in the north the karelian margin has been both over and underthrust by the savo arc cfa comprises a folded thrust package on top of a continental nucleus and the savo arc the associated subduction zone and accretionary prism are interpreted to lie to the south underneath the bothnian basin area where prominent ne dipping lower to middle crustal reflections are found along babel profiles 1 and 4 an oblique collision of the central finland arc and the continent resulted in the development of the strike slip fault on the young hot savo arc babel profiles 1 6 7 and c image the internal architecture of the southern and central finland arcs the unusually thick crust 55 60 km hosts unreflective high density mafic intrusions acting as a crustal indentor a highly reflective antiform structure developed on the southern side of it southern finland arc complex sfa is an imbrication structure comprising stacked slices of arc related crust on an older continental nucleus bergslagen nucleus prior to the collision the sfa suffered from gravitational collapse during which the crust was thinned profile b images the architecture of the central and southern swedish svecofennides the sormland terrane sob is interpreted as the accretionary prism of the southern finland arc squeezed between the svecofennian collage in the north and the advancing continent to the south the southern continent island arc is characterised by ne dipping crustal reflections and moho offsets as well as step wise increasing thickness of the crust after the final collision large volumes of mantle derived material intruded the crust as large mushroom shaped plutons they are interpreted as the heat source for the tib magmatism in southern and western scandinavia

metallogeny of gold in the precambrian of northern europe fennoscandian gold deposits have been successfully explored in a wide range of precambrian geological environments in sweden and finland during the last two decades under explored areas still exist at other sites in the fennoscandian shield particularly in russia and norway and there is a high potential for future new discoveries of economic gold in northern europe careful geological documentation of a number of previously productive gold deposits such as haveri and saattopora finland boliden adelfors and enasen sweden and eidsvoll and bidjovagge norway is now available in the literature kutemajarvi pahtavaaraa and suurikuusikko finland and bjorkdal akerberg harnas and pahtohavare sweden represent a new generation of gold mines and recent research on these enables an improved base for formulating regional and local metallogenetic models younging trends from northeast to southwest characterize both the crust and ore forming regional patterns in the fennoscandian shield orogenic or mesothermal gold deposits are found in a wide range of host rocks and are closely linked to either the paleoproterozoic svecokarelian or the neoproterozoic sveconorwegian orogeny unlike these shear zone related deposits significant amounts of gold were concentrated in volcanogenic massive sulfide vms deposits by magmatic hydrothermal processes in conjunction with formation of paleoproterozoic svecofennian juvenile crust hundreds of gold deposits of a variety of ages and genetic styles are therefore now known in the precambrian of northern europe of which some are economic others subeconomic and still others only of scientific interest one hundred representative deposits in sweden norway finland and russia are discussed in this review literature references are provided for each of them and detailed maps show the location of each deposit or prospect listed data on tonnage and grades for the most recent exploration targets as well as the economically and historically most significant deposits show that they were formed during the entire precambrian yield of gold in the fennoscandian shield is so far confined to proterozoic deposits but the potential to find economically viable gold deposits in the russian parts of the archean greenstone belts should not be underestimated

the development of antarctic katabatic winds and implications for the coastal ocean the influence of katabatic winds on the antarctic coastal waters is examined by using simple models of the ocean and atmosphere a katabatic flow model incorporating coriolis dynamics is solved analytically and another with nonlinear friction is solved numerically to provide wind stress to a two layer coastal ocean model the resulting solutions are evidently the first to incorporate coriolis terms with a thermodynamic equation that includes compressional warming effects the emphasis in this paper is on delineating the parameters that control the relative adjustment of the katabatic wind into alongshore and offshore components by including nonlinear friction it is shown that steeper slopes and weaker stratification tend to direct the wind more toward the ocean it is further demonstrated that the katabatic forcing supports the strong polar easterlies winds from the east along the periphery of the continent and that the offshore extent should be dependent on the atmospheric rossby deformation radius the ocean model shows that significant downwelling occurs at the coast while upwelling is predicted at a distance of the order of the ocean rossby radius an alongshore coastal jet from the east is found in the model and is evidently the manifestation of the east wind drift the upwelling offshore may be a significant aspect of polynya formation and maintenance of the antarctic divergence zone and contribute to the biological productivity of the region

the origin of chlorite tremolite carbonate rocks associated with the thalanga volcanic hosted massive sulfide deposit north queensland australia the thalanga polymetallic massive sulfide deposit is hosted by felsic volcanics of the cambro ordovician mount windsor subprovince in north queensland the sheetlike sulfide deposit consists of several semiconnected lenses totaling 6 6 million metric tons mt which lie at a single stratigraphic level between underlying subaqueously emplaced rhyolite and overlying dacitic to andesitic lavas sills and volcaniclastic rocks the ores and host rocks have been deformed and metamorphosed to upper greenschist facies associated with the west thalanga orebody are strata bound lenses composed of chlorite tremolite dolomite and calcite that previously have been interpreted as exhalites they extend up to a few hundred meters along the mineralized horizon and locally also exist in the stratigraphic footwall around the fringes of the deposit rhyolitic volcanics beneath the deposit are extensively altered a pervasive sericite chlorite pyrite zone that extends greater than 200 m into the footwall envelops semistratiform proximal quartz pyrite chlorite stringer zones major and trace element geochemical data indicate that zr ti and al remained essentially immobile in the footwall rocks despite intense hydrothermal alteration involving significant mass transfers of mobile elements the chlorite tremolite carbonate assemblages associated with ore lenses have immobile element ratios identical to those of the altered rhyolites carbonate rich assemblages retain some relict spheroidal and rhombic textures in dolomite which suggest formation at an early hydrothermal stage in a matrix of chlorite or in open spaces the chlorite tremolite carbonate rocks probably represent metamorphic equivalents of hydrothermal chlorite quartz dolomite calcite or mg smectite quartz dolomite calcite assemblages the formation of tremolite by metamorphic reaction of quartz and dolomite is consistent with regional metamorphic conditions with allowance for metamorphic decarbonation carbon and oxygen isotope data from dolomite and calcite are consistent with precipitation of primary dolomite at 170 to 250 c from seawater dominated fluid the chlorite tremolite carbonate rocks at thalanga are consequently reinterpreted as altered rhyolitic volcaniclastics containing variable proportions of hydrothermal carbonate they probably formed in a zone of mixing of hydrothermal fluid and seawater in a permeable substrate close to the paleosea floor siliceous ironstones that are present in distal parts of some thalanga ore lenses have very low immobile element contents and are probably true exhalites

magnetic characterisation of magnetite and hematite from the blotberget apatite iron oxide deposits bergslagen south central sweden rock magnetic measurements were carried out on drill core material and hand specimens from the blotberget apatite iron oxide deposit in the bergslagen ore province south central sweden to chara

case study of a barrier wind corner jet off the coast of the prince olav mountains antarctica abstractthe ross ice shelf airstream ras is a barrier parallel flow along the base of the transantarctic mountains previous research has hypothesized that a combination of katabatic flow barrier winds and mesoscale and synoptic scale cyclones drive the ras within the ras an area of maximum wind speed is located to the northwest of the protruding prince olav mountains in this region the sabrina automatic weather station aws observed a september 2009 high wind event with wind speeds in excess of 20 m s 1 for nearly 35 h the following case study uses in situ aws observations and output from the antarctic mesoscale prediction system to demonstrate that the strong wind speeds during this event were caused by a combination of various forcing mechanisms including katabatic winds barrier winds a surface mesocyclone over the ross ice shelf an upper level ridge over the southern tip of the ross ice shelf and topographic influences from the prince olav mountains these forcing mechanisms induced a b

mesoscale cyclone activity over antarctica during 1991 1 marie byrd land a 1 year statistical study of mesoscale cyclonic activity over southern marie byrd land west antarctica was conducted using high resolution satellite imagery collected insitu during 1991 at the u s mcmurdo and palmer stations results indicate that on average one or two mesoscale cyclones can be observed each week over the southernmost part of marie byrd land siple coast and adjacent areas where cold katabatic winds from the high plateau of east antarctica and relatively warm katabatic airflows from west antarctica interact forming a boundary layer baroclinic zone in the form of a stationary front the 1991 annual mesoscale cyclone behavior exhibits maximum activity in march and minimum in september analysis of the large scale pattern for these months suggests that the higher activity in march is associated with synoptic scale conditions that support the cold katabatic drainage from east antarctica and favor warm air advection into west antarctica a situation that can form and or enhance the boundary layer baroclinic zone more than half 70 of the mesoscale vortices observed near siple coast were of comma cloud type with an average diameter of about 250 km their satellite signature characteristics show that these cyclonic perturbations were stratiform low cloud features indicating that most of them developed within the lower troposphere more than likely below 700 hpa according to a cloud top temperature evaluation

characteristics of the ross ice shelf air stream as depicted in antarctic mesoscale prediction system simulations 1 streamlines of the mean annual near surface winds over the antarctic continent suggest a confluent channeling of the drainage flows off the ice sheets and onto the ross ice shelf a persistent cyclonic circulation to the north of the ice shelf supports a large scale pressure field that reinforces the continental drainage flows owing to these two processes an enhanced low level airflow is present along the southern and western sections of the ross ice shelf the resulting air stream known as the ross ice shelf air stream ras is one of the persistent and prominent low level wind features seen in the antarctic real time mesoscale simulations of the antarctic atmosphere and high southern latitudes using a modified version of the pennsylvania state university national center for atmospheric research mesoscale modeling system have been ongoing since the 1999 2000 austral field season model results from the 1 year period november 2001 to october 2002 have been analyzed to investigate the mean structure and modulation of the ross ice shelf air stream analyses of model results show the low level air stream over the western ross ice shelf has a wind speed maxima that is linked to the steep topography to the west individual cases of strong wind events appear to contain a significant barrier wind component that arises from cold air damming against the transantarctic mountains cyclones that frequently form in the ross sea are shown to establish conditions that promote barrier wind dynamics and thus significantly modulate the intensity of the ras

the role of eolian processes in forming surface features of the martian polar layered deposits abstract the major topographic features of the martian polar layered deposits include the conspicuous spiral troughs subtle undulations broad reentrants chasma steep arcuate scarps and dune fields a prominent role for eolian processes in the formation of all of these features is proposed strong katabatic winds occur on the north polar cap producing widespread frost streaks these cold drainage winds are analogous to those on the terrestrial antarctic cap in the chasmae convergent katabatic winds create yardangs and erode arcuate scarps in the layered deposits that are also the source for local dune fields migrating outward from the polar cap the chasmae are postulated to originate by long term erosion by katabatic wind wind plays a role in formation of the troughs and scarps primarily through removal of dust freed from exposed layered deposits by ablation of ice on defrosted equator facing slopes the undulations are created by interaction between surface erosion or deposition of perennial ice and standing waves in the shallow katabatic windflow the south polar layered deposits exhibit topographic features similar to those at the north polar cap but erosion and depositional processes creating these features may be inactive during the current epoch because of the lack of an extensive perennial ice cover and associated katabatic wind

an analysis of low level jets in the greater ross ice shelf region based on numerical simulations abstract an analysis of the presence and location of low level jets lljs across the ross ice shelf region in antarctica is presented based on the analysis of archived output from the real time antarctic mesoscale prediction system amps the method of self organizing maps soms is used to objectively identify different patterns in column averaged wind speed over the approximately lowest 1200 m of the atmosphere as an identifier to the location of lljs the results indicate three primary lljs in the region the largest and most dominant llj is along the transantarctic mountains by the siple coast and the southern end of the ross ice shelf the second llj extends from the base of byrd glacier and curves to the north passing by the eastern extremes of ross island the third llj extends from the base of reeves glacier and curves to the north across the western ross sea a strong seasonality is observed in the frequency and intensity of the lljs with the highest values for wind speed and the size of the

climatic atmospheric outflow at the rim of the antarctic continent using gauss s divergence theorem we examine the role of the net radiative cooling and of the entrainment of potentially warm air from the free atmosphere into the surface layer in determining the intensity of the cold air outflow at the rim of the antarctic continent the result shows that a large amount of cold air significant at even a global climatological scale is exported through this process from high to low latitude regions the theory gives also the average intensity of the wind at the coast in the coastal regions of antarctica the wind exhibits a complex behavior observations show that katabatic winds in the near coastal region can be periodic or continuous or can stay a long time in a quiescent near critical state then burst in short and strong gusts we examine some aspects of these katabatic winds in terms of the mesoscale energy theory developed by dalu and green 1983 this complex behavior is described by a nonlinear system where the relevant parameter is the froude number of the inflow at a rossby radius distance from the coast the analytical theory developed agrees well with qualitative features observed

the influence of antarctica on the momentum budget of the southern extratropics the antarctic plateau acts as a strong heat sink for the global climate cooling the atmosphere and radiating energy to space a cold dense atmospheric boundary layer is formed strong surface winds are formed as the boundary layer drains off the plateau these drainage winds and the eddy fluxes necessary to maintain them are analysed in a general circulation model gcm the drainage flow is well represented in the gcm the associated mean meridional circulation is analysed in isentropic coordinates the momentum budget over antarctica reveals a balance between the eliassen palm flux convergence and the coriolis torque exerted by the mean meridional mass flux both vertical and horizontal components of the eliassen palm flux contribute the vertical component being the greater

facies analysis of a 1 9 ga continental margin back arc felsic caldera province with diverse zn pb ag cu au sulfide and fe oxide deposits bergslagen region sweden the bergslagen mining district in south central sweden has been a major metal producer for more than 1 000 years in geologic terms bergslagen is the intensely mineralized part of a large early proterozoic mainly 1 90 1 87 ga felsic magmatic region of mainly medium to high metamorphic grade in the baltic shield the district contains a diverse range of ore deposit types including banded iron formation magnetitecalc silicate skarn manganiferous skarn and carbonate hosted iron ore apatite bearing iron ore stratiform and strata bound zn pb ag cu au sulfide ores and w skarn most ore deposits occur in hydrothermally altered metavolcanic rocks and associated metalimestones and skarns this study is a field oriented regional facies analysis based on recognition of primary volcanic and sedimentary features through the strong overprints of hydrothermal alteration deformation and metamorphism the region is interpreted as an extensional probably back arc active continental margin magmatic region it evolved through stages of intense magmatism thermal doming and crustal extension followed by waning extension waning volcanism thermal subsidence reversal from extension to compressional deformation regional metamorphism and structural inversion the volcanic successions comprise interfingering proximal near vent medial volcano flanks and distal volcano margin facies associations of rhyolitic pyroclastic caldera volcanoes and subordinate dacite rhyolite complexes nonwelded to poorly welded pyroclastic flow and fallout units and their rapidly resedimented subaerial and subaqueous equivalents are the most abundant volcanic facies subvolcanic porphyritic intrusions and cryptodomes are also abundant the pyroclastic debris was shed from mainly shallow water and subaerial proximal areas to shallow and moderately deep water above and below storm wave base distal areas most ore deposits formed during the regional waning volcanic stage and occur in medial to distal facies associations that comprise rhyolitic ash siltstone limestone and vitric crystal sandstone and breccia these mineralized facies associations were deposited in subaqueous environments mainly below the fair weather wave base but locally above the storm wave base water depths are interpreted to have been mainly 10 to 500 m with local deeper areas although the ore deposits occur in medial to distal facies associations many occur above or laterally adjacent to subsided volcanic vent complexes this suggests a spatial temporal and possible genetic relationship between several ore deposit types and the late magmatic stage of these volcanic centers except for the apatite bearing iron deposits it is uncertain if the ores are genetically related to specific magmatic hydrothermal events from specific volcanoes this is possible especially for the base metal sulfide deposits which have intense localized footwall alteration in felsic volcanic rocks however an important role of the volcanic centers may have been to provide strong positive pertubations or magmatic hydrothermal input to the regional convective geothermal system the main zn pb ag cu au ore deposits span a range between two end member types stratiform ash siltstone hosted sea floor deposits that have similarities to some stratiform sediment hosted zn pb ag deposits especially the broken hill type deposits and strata bound volcanic associated limestone skarn subsea floor replacement deposits that more closely resemble felsic volcanic associated massive sulfide deposits facies models are presented for both the banded iron formations are interpreted as chemical suspension deposits rhythmically interbedded with rhyolitic ash siltstone the skarn iron ores are strata bound in limestones and include metamorphosed sedimentary ores and metasomatic replacements apatite bearing iron ores differ in setting from the other ores in being formed within a dacitic intrusive complex that may be the root zone of a dacite rhyolite volcanic center

detection of leakage paths at the wanyao dam body in southwest china by hydrochemical analysis and tracer testing leakage at the wanyao dam body was studied using a combined approach of field exploration hydrochemical analysis and tracer testing the objective of study was to determine the location of the water leakage paths at the dam a hydraulic connection was observed between exploration boreholes of dam crest and drain holes at drainage gallery during the period of drilling this connection shows that there were some defects in the dam the hydrochemical compositions and characteristics of the water samples involved the main anions and cations total dissolved solids electrical conductivity ph and water temperature which were analyzed and evaluated by correlation and cluster analysis the results indicated that a close hydraulic connection existed between water from the dam body and reservoir water particularly reservoir water from sections iii and ix tracer testing results demonstrated further existence of leakage paths between reservoir water and sections iii and ix also there were multiple leakage paths in section ix compared with a single path of section iii furthermore the leakage location of upstream concrete faces in the vertical and horizontal directions was determined accurately with the measured electrical conductivity of receiving points the experimental data provide a strong foundation and basis for maintaining and reinforcing the dam

lineations on the white accumulation areas of the residual northern ice cap of mars their relation to the accublation and ice flow hypothesis abstract mars orbiter camera moc images of the whiter areas of the residual north polar cap p c thomas et al 2000 nature404 161 164 show a gentle hummocky pitted surface that has been popularly called cottage cheese terrain the pits are 1 or 2 m deep and tens of meters across they are typically joined in roughly linear strings or long depressions and these features are referred to here as lineations the lineations tend to have one or occasionally two preferred directions we have examined the moc imagery for the north cap and using high resolution images that have good wide angle context images were able to determine the lineation angles for 31 sites scattered over most of the ice cap we propose a process that will produce linear features in the white areas then relate the orientation of the lineations over much of the north cap to these processes and the inferred ice flow direction there is first order agreement between the measured sign of the lineation angles and those predicted assuming ice flow higher accumulations and velocities are predicted in the catchment for ice that flows into chasma boreale this comes from the indications that katabatic winds are concentrated in this catchment

meteorite concentrations in antarctica sites of katabatic wind ablation blue ice fields on antarctica have yielded over 10 000 fragments of extraterrestrial material yet the mechanism for these concentrations remains enigmatic focus has been placed on the role of glaciological processes i here propose that meteorological processes are also significant katabatic winds possess the necessary attributes to account for substantial sublimation of the ice in very localized zones recent studies indicate that these winds have distinct confluences along the coastal slopes of the antarctic plateau a tentative correlation of these with meteorite accumulations is suggested figure 1 though more year round surveillance of the local wind regimes is required before a working hypothesis can be proposed