spirit mars rover mission to the columbia hills gusev crater mission overview and selected results from the cumberland ridge to home plate this paper summarizes the spirit rover operations in the columbia hills of gusev crater from sols 513 to 1476 and provides an overview of selected findings that focus on synergistic use of the athena payload and comparisons to orbital data results include discovery of outcrops voltaire on husband hill that are interpreted to be altered impact melt deposits that incorporated local materials during emplacement evidence for extensive volcanic activity and aqueous alteration in the inner basin is also detailed including discovery and characterization of accretionary lapilli and formation of sulfate silica and hematite rich deposits use of spirit s data to understand the range of spectral signatures observed over the columbia hills by the mars reconnaissance orbiter s compact reconnaissance imaging spectrometer crism hyperspectral imager 0 4 4 m is summarized we show that crism spectra are controlled by the proportion of ferric rich dust to ferrous bearing igneous minerals exposed in ripples and other wind blown deposits the evidence for aqueous alteration derived from spirit s data is associated with outcrops that are too small to be detected from orbital observations or with materials exposed from the shallow subsurface during rover activities although orbital observations show many other locations on mars with evidence for minerals formed or altered in an aqueous environment spirit s data imply that the older crust of mars has been altered even more extensively than evident from orbital data this result greatly increases the potential that the surface or shallow subsurface was once a habitable regime

glacier recession and water resources in peru s cordillera blanca the tropical glaciers of the cordillera blanca peru are rapidly retreating resulting in complex impacts on the hydrology of the upper rio santa watershed the effect of this retreat on water resources is evaluated by analyzing historical and recent time series of daily discharge at nine measurement points using the mann kendall nonparametric statistical test the significance of trends in three hydrograph parameters was studied results are interpreted using synthetic time series generated from a hydrologic model that calculates hydrographs based on glacier retreat sequences the results suggest that seven of the nine study watersheds have probably crossed a critical transition point and now exhibit decreasing dry season discharge our results suggest also that once the glaciers completely melt annual discharge will be lower than present by 2 30 depending on the watershed the retreat influence on discharge will be more pronounced during the dry season than at other periods of the year at la balsa which measures discharge from the upper rio santa the glacier retreat could lead to a decrease in dry season average discharge of 30

the impact of glaciers on the runoff and the reconstruction of mass balance history from hydrological data in the tropical cordillera blanca peru a 41 years series of runoff and precipitation data from the peruvian cordillera blanca demonstrates the high hygric seasonality in this tropical high mountain range in this area glaciers have a crucial impact on runoff which is of essential importance for the highly populated and cultivated valley of the callejon de huaylas particularly during the dry season whereas the mid latitudes glacier runoff amplifies the seasonal variation of runoff the effect of glaciers in the low latitudes is a smoothing one it decreases clearly with the decreasing degree of glaciation in addition particular circumstances of this tropical environment allow the reconstruction of a glacier mass balance history from the hydrological data for the second half of the 20th century it shows a high synchronicity with the global trend of periods with glacier mass loss and gain comparison with length variations of three individual glaciers indicate a rather fast reaction of these glaciers to changes in mass balance although the mass balance variations show some differences among the individual catchment basins the over all trend is uniform a general positive correlation of mass balance variations with soi is obvious but not regular

mass balance model parameter transferability on a tropical glacier we explore the small scale spatial and temporal transferability of model parameters between two points in the ablation zone of tropical glaciar shallap cordillera blanca peru 9 s 77 w 4800 m a s l in order to provide a robust assessment of the performance of a process based glacier mass balance model relative surface height change is calculated at hourly time steps and cumulative values are compared to surface height measurements made at irregular intervals 14 64 days over the course of two continuous hydrological years august 2006 august 2008 best performing parameter combinations were determined for each point from the outcome of 1000 model simulations for which parameters were varied randomly within a defined range with these parameter combinations measurements for a specific location and time span are well reproduced transferring the parameter combination as optimized for one location to the other location in the ablation zone increases the errors of modeled cumulative mass balance by 5 1326 mm ice eq a 1 transferring the parameter combinations as optimized for one year to the other year increases the modeled errors in cumulative mass balance by 18 3179 mm ice eq a 1 model errors generally increase during periods with frequent snowfall and snow cover this could reflect either the inherent difficulty of modeling complex snow processes or the inability of the model to correctly capture the pattern of albedo evolution at this site the magnitude of errors associated with parameter transfer in space and time highlights the need for improving model performance for robust climatological and or hydrological analyses on tropical glaciers

in situ weathering rind erosion abstract the use of cosmogenic nuclide dating methods place in doubt the long term future of weathering rinds wrs as a chronometric tool why estimate ages when radiometric control is possible this paper presents evidence that wrs can provide invaluable clues about what particular sample would provide the most accurate cosmogenic age by avoiding inheritance of cosmogenic nuclides and by avoiding boulders undergoing spalling the key to this new use requires testing the occurrence and nature of wr erosion back scattered electron microscopy reveals that ignimbrite andesite basalt and granitic clasts experience wr erosion in all subsurface and surface contexts thus far studied in arizona california hawaii oregon and washington to understand the magnitude of wr erosion we measured wr thicknesses all while controlling the cosmogenic and surface stability ages of clasts by chlorine 36 and rock varnish microlamination dating methods our data reveal that traditional methodologies of sampling cobbles remove two thirds of the true thickness of weathering rinds calling into question many beliefs including the notion that clay minerals are not produced during weathering rind formation comparisons of optical and electron microscope measurements support concerns that measurement of wrs by color changes while useful as a pedagogical tool creates serious biases in underestimating the true dynamics of wrs in the end we found that concordance of wr and rock coating age trends indicates the ideal boulder for cosmogenic nuclide dating offsets reveal either ongoing boulder erosion invalidating zero erosion model ages or a potential problem with inheritance of cosmogenic nuclides

the climate of the altiplano observed current conditions and mechanisms of past changes abstract the large scale controls on the climate of the south american altiplano are investigated using local observations reanalysis data and general circulation model experiments the objective is to gain understanding of causes of climate variability and climate change by relating mechanisms that operate on timescales ranging from the intraseasonal to the glacial interglacial our results suggest that on all timescales the climatic conditions on the altiplano are closely related to the upper air circulation with an easterly zonal flow aloft favoring wet conditions and westerly flow causing dry conditions different factors influence the upper air circulation on the different timescales intraseasonal variability is a reflection of the position and intensity of the bolivian high which is modulated by rossby waves emanating from the midlatitude south pacific the annual cycle of dry winter and wet summer conditions is caused by the seasonal expansion of the equatorial easterlies in the upper troposphere rather than direct insolation forcing over the altiplano or moisture changes in the source area interannual variability is primarily related to changes in the mean zonal flow over the altiplano reflecting changes in meridional baroclinicity between tropical and subtropical latitudes which in turn is a response to sea surface temperature changes in the tropical pacific orbitally forced changes in the land sea contrast drive continental scale circulation changes which significantly alter the zonal flow over the altiplano on glacial interglacial timescales the contrast in heating between northern and southern hemispheres during the glacial leads to upper air easterly anomalies throughout the tropics on modern timescales the marked submonthly seasonal and interannual changes of moisture over the altiplano cannot be accounted for by moisture changes in the humid tropical lowlands however the model experiments suggest that cooler conditions during a glacial reduce moisture availability from the tropical lowlands which counteracts the effect of the upper level circulation resulting in little overall change in precipitation this observational and modeling analysis provides a physical framework for relating the mechanisms of both internal and forced climate change on the altiplano on a wide range of timescales

can the snowline be used as an indicator of the equilibrium line and mass balance for glaciers in the outer tropics because the glacier snowline is easy to identify on optical satellite images and because in certain conditions it can be used as an indicator of the equilibrium line it may be a relevant parameter for the study of the relationships between climate and glaciers although several studies have shown that the snowline altitude sla at the end of the hydrological year is a good indicator of the equilibrium line altitude ela for mid latitude glaciers such a relationship remains conjectural for tropical glaciers indeed unlike in mid latitudes tropical climate conditions result in a distinct seasonality of accumulation ablation processes we examine this relationship using direct field ela and mass balance measurements made on glaciar zongo bolivia 168 s and glaciar artesonraju peru 98 s and the sla retrieved from satellite images acquired in the past two decades we show that on glaciers in the outer tropics 1 ablation is reduced during the dry season in austral winter may august the sla does not change much and satellite images acquired between may and august could be used to compute the sla and 2 the highest sla detected on a number of satellite images acquired during the dry season provides a good estimate of the annual ela however as snowfall events can occur during the dry season the sla detected on satellite images tends to underestimate the ela thus we recommend validating the sla computed from satellite images with field data collected on a benchmark glacier before measuring the sla on other glaciers in the same mountain range for which no field data are available this study is a major step towards extending the measurement of glacier parameters ela and mass balance at the scale of a whole mountain range in the outer tropics to better document the relationships between climate and glaciers

basalt weathering in an arctic mars analog site abstract the martian surface has undergone chemical and physical weathering in the past and these processes may continue intermittently today to explore whether martian rocks are likely to retain features indicative of weathering we investigated how basaltic material weathers on earth specifically we investigated weathering of a quaternary aged basaltic flow at the sverrefjell volcano in svalbard above the arctic circle this flow weathered since deglaciation under cold dry

glacier climate interaction at low latitudes in the low latitudes there is an absence of major thermal seasonality yet there are three different climate regimes related to global circulation patterns and their seasonal oscillation the humid inner tropics the dry subtropics and intermediate between these two the outer tropics for the respective glacier regimes the vertical profiles of specific mass balance vbps are modeled considering vertical gradients of accumulation air temperature and albedo the duration of the ablation period and a factor for the ratio between melting and sublimation the model is first calibrated with data from hintereisferner austrian alps and is then applied to tropical conditions the simulated vbp matches well the measured profiles from irian jaya and mount kenya due to lack of field evidence the subtropical vbp cannot be verified directly however application of the respective model versions separately to the humid and dry seasons of the outer tropical glaciar uruashraju cordillera blanca peru provides reasonable results glaciers in the humid inner tropics are considered to be most sensitive to variations in air temperature while dry subtropical glaciers are most sensitive to changes in air humidity the two seasons of the outer tropics have to be viewed from these different perspectives

the freezing level in the tropical andes peru an indicator for present and future glacier extents along with air temperatures the freezing level height flh has risen over the last decades the mass balance of tropical glaciers in peru is highly sensitive to a rise in the flh mainly due to a decrease in accumulation and increase of energy for ablation caused by reduced albedo knowledge of future changes in the flh is thus crucial to estimating changes in glacier extents since in situ data are scarce at altitudes where glaciers exist above 4800 m above sea level asl reliable flh estimates must be derived from multiple data types here we assessed the flhs and their spatiotemporal variability as well as the related snow rain transition in the two largest glacier covered regions in peru by combining data from two climate reanalysis products tropical rainfall measuring mission trmm precipitation radar bright band data micro rain radar data and meteorological ground station measurements the mean annual flh lies at 4900 and 5010 m asl for the cordillera blanca and vilcanota respectively during the wet season the flh in the cordillera vilcanota lies 150 m higher compared to the cordillera blanca which is in line with the higher glacier terminus elevations coupled model intercomparison project version 5 cmip5 climate model projections reveal that by the end of the 21st century the flh will rise by 230 m 190 m for representative concentration pathway rcp 2 6 and 850 m 390 m for rcp8 5 even under the most optimistic scenario glaciers may continue shrinking considerably assuming a close relation between flh and glacier extents under the most pessimistic scenario glaciers may only remain at the highest summits above approximately 5800 m asl

geophysical evidence for gas hydrates in the deep water of the south caspian basin azerbaijan new 2 d seismic reflection data from the south caspian sea offshore azerbaijan document for the first time in the deep water up to 650 m of this area the presence of gas hydrates geophysical evidence for gas hydrates consists of a shallow 300 500 m below seafloor zone of pronounced high velocity 2 100 m s as compared with the surrounding sediments 1550 1600 m s this zone appears on the seismic data as a depth limited 200 m thick layer extending down the flank of an elongate structural high and displays seismic blanking effects on the sedimentary section a strong positive polarityorc 0 123u reflector marks the top of this velocity anomaly and is interpreted as the top of the gas hydrate layer similarly a high amplitudeorc 0 11u negative polarity reflector coincides with the base of the highvelocity layer and is interpreted as the base of the hydrate zone both the top and bottom of the hydrate layer approximately parallel the seafloor bathymetry and cut discordantly across the stratigraphic section suggesting that the two reflectors are thermobaric and not stratigraphic interfaces decreasing amplitude with offset at the base of the gas hydrate layer may indicate the accumulation of free gas beneath this interface these gas hydrates fall within the hydrate stability field predicted from thermobaric modeling for the south caspian basin but typically in thinner layers than would be expected from theoretical calculations the minimum predicted water depth that allows hydrate formation is 150 m and the maximum predicted thickness of the gas hydrate stability field is 1350 m q 2001 elsevier science ltd all rights reserved

halloysite as a kinetically controlled end product of arid zone basalt weathering abstract mineralogical and isotope results paired with field observations suggest that halloysite is the favored albeit metastable aluminosilicate end product of arid zone basalt weathering on kohala hawai i and that the formation of smectite has been inhibited by kinetic factors soils sampled on constructional lava flows having ages ranging from 4 to 350 ka provide a chronosequence that has had minimal physical disturbance thus allowing us to interpret chemical and mineralogical changes as the result of a time dependent process the halloysite content of the soil increases with increasing soil age its growth is at the expense of allophane which in turn forms at the expense of primary minerals these mineral relationships suggest that halloysite has been forming continuously throughout the lifetime of the soil smectite the thermodynamically stable phyllosilicate phase predicted by soil solution composition is not found in these arid soils we determined that our soil system is controlled by kinetic factors and that therefore thermodynamic predictions do not reflect reality the main factors favoring kinetic control of halloysite formation are intense but short wet periods followed by prolonged extremely dry seasons and microenvironmental conditions leading to immediate uptake of released al by the halloysite precursor mineral allophane the 18o relationship between present day soil water and halloysite formed over the last 170 ka was used as a tracer of past soil conditions results from a reconstruction of paleo climate and soil conditions combined with 18o data observed mineral relationships along the 350 ka chronosequence and field evidence for long term aridity rule out the possibility that the arid side of kohala was affected by prolonged periods of higher rainfall that could have produced more dilute soil waters and therefore altered mineralogical stabilities we conclude that pedogenic halloysite has been continually forming from the early stage of soil formation and that it has consistently formed under isotopic equilibrium conditions indicating that halloysite 18o compositions imply paleoclimatic conditions over the time of its formation that are similar to today s

hydrothermal origin for carbonate globules in martian meteorite alh84001 a terrestrial analogue from spitsbergen norway carbonate minerals in the ancient martian meteorite alh84001 are the only known solid phases that bear witness to the processing of volatile and biologically critical compounds co2 h2o on early mars similar carbonates have been found in xenoliths and their host basalts from quaternary volcanic centers in northern spitsbergen norway these carbonates were deposited by hot i e hydrothermal waters associated with the volcanic activity by analogy with the spitsbergen carbonates the alh84001 carbonates were probably also deposited by hot water hydrothermal activity was probably common and widespread on early mars which featured abundant basaltic rocks water as ice or liquid and heat from volcanos and asteroid impacts on earth descendants of the earliest life forms still prefer hydrothermal environments which are now shown to have been present on early mars

model study of the spatial distribution of the energy and mass balance of morteratschgletscher switzerland to investigate the spatial distribution of the energy and mass balance fluxes of a glacier a two dimensional mass balance model was developed and applied to morteratschgletscher switzerland the model is driven by meteorological input from four synoptic weather stations located in the vicinity of morteratschgletscher the model results were compared to observations made on the glacier the calculated mean specific mass balance is 0 47 m w e for 1999 and 0 23 m w e for 2000 net shortwave radiation shows a minimum at around 3350 m a s l due to the effects of shading slope aspect reflection from the slopes and obstruction of the sky ignoring these effects results in a 37 increase in the annual incoming shortwave radiation on the glacier causing 0 34 m w e more ablation a 1 c change in the air temperature results in a shift of 0 67 m w e in the mean specific mass balance while altering the precipitation by 10 causes a change of 0 17 m w e

70 years of lake evolution and glacial lake outburst floods in the cordillera blanca peru and implications for the future climate change glacier retreat and glacial lake outburst floods glofs are intertwined the cordillera blanca in peru has one of the world s longest glof records and here we assess the evolution of glacial lakes in the region between 1948 and 2017 and investigate the links to documented glofs we also model future lake evolution under two climate scenarios to provide an assessment of current and future glof triggering potential our analysis shows that the number of lakes as well as the total lake area has increased during the historical period the formation of new lakes is however not uniform among different lake types with bedrock dammed lakes exhibiting the largest increase in recent decades we argue that moraine dammed lakes have already formed at the majority of potential locations in the cordillera blanca and that the next generation of lakes which are expected to form in response to glacier retreat over topographically suitable areas will be predominantly bedrock dammed based on a regional glof inventory we show that the peak frequency of glofs occurred from the late 1930s to early 1950s while glofs originating from moraine dammed lakes dominated in this period recent glofs have originated from bedrock dammed lakes at the same time the majority of glofs originated from lakes in a proglacial phase i e in contact with glacier even though the share of proglacial lakes did not exceed 12 at any time step during the analysed period while many moraine dammed lakes evolved into the glacier detached evolutionary phase bedrock dammed lakes became a major lake dam type among proglacial lakes over the remainder of the 21st century a further increase in lake area of up to 10 is anticipated with up to 50 new bedrock dammed lakes likely to develop as glaciers retreat there is little difference in lake development and glof triggering potential under climate scenarios driven by rcp 2 6 and 8 5 based on topographic disposition recent and future lakes do not individually appear more or less susceptible to landslide impact than lakes that already developed earlier in the 20th century synthesizing these findings we forecast that bedrock dammed lakes will become the dominant source of glofs in the next decades because such dams are inherently more stable we expect overall lower glof magnitudes compared to documented glofs from moraine dammed lakes

evaluation of recent glacier recession in the cordillera blanca peru ad 1962 1999 spatial distribution of mass loss and climatic forcing we use a combination of aerial photogrammetry satellite imagery andd ifferential gps mapping to quantify the volume of ice lost between ad 1962 and 1999 from three glaciers on nevado queshque in the cordillera blanca peru 101s the largest averagedsurface lowering thinning occurredin the southwest aspect 22 m andthe least in the eastern aspect 5 m a heuristic sensitivity analysis indicates that 9 3 w m 2 was requiredto melt the total observedice loss andthis can be explainedby sensible heat transfer relatedto a temperature rise of 1 1c combinedwith a latent heat d ecrease relatedto a 0 14 g kg 1 increase in specific humidity a first difference analysis of temperature records from 29 stations in the cordillera blanca shows an average rising trend of 0 261c per decade over the 37 year interval more than adequate to supply the hypothesized sensible heat transfer a simple transmittivity model within a digital elevation model indicates solar radiation related to altered cloudiness was not a predominant climatic forcing the distribution of glacier area with altitude calculated with the digital terrain model explains the observed asymmetrical ice melt r 2005 elsevier ltd all rights reserved

tropical glacier meltwater contribution to stream discharge a case study in the cordillera blanca peru original abstract discharge measurements climate observations and hydrochemical samples gathered monthly 1998 99 in the yanamarey and uruashraju glacier fed catchments of the cordillera blanca peru permit an analysis of the glacier meltwater contribution to stream flow these glacier catchments feed the rio santa which discharges into the pacific ocean based on a water balance computation glacier melt contributes an estimated 35 of the average discharge from the catchments for comparison a volumetric end member mixing model of oxygen isotopes shows glacier melt contributes 30 45 to the total annual discharge based on stream geochemistry discharge from the yanamarey glacier catchment provides 30 of the annual volume discharged from the querococha watershed which is 10 glacierized by analogy the larger rio santa watershed also 10 glacierized receives at least 12 of its annual discharge from melting glacier ice tributary watersheds to the rio santa with larger fractions of glacier cover have less variable runoff and enhanced discharge demonstrating that the glaciers effectively buffer stream discharge seasonally with continued glacier melting stream flow will likely become more variable and there will be less dry season runoff

quantification of the dry history of the martian soil inferred from in situ microscopy 1 the particle size distribution psd of a martian soil sample a useful indicator of the underlying soil formation processes has been determined using optical and atomic force microscopy data acquired by the phoenix mars lander in particular the presence and fraction of clay sized particles in the psd reflects the extent of aqueous interaction with the soil two size populations have been identified for the martian sample larger mostly rounded grains and small reddish fines notably with a very low mass proportion in the clay size range below 2 m these fines reflect the smallest scale formation processes and indicate a single method of production for the particles up to 11 m a much larger value than that expected for the aqueous interaction of clay formation this suggests the fines are predominantly the product of global aeolian weathering under very dry conditions the proportion of clay sized soils can be used to estimate that there has been much less than 5 000 years exposure to liquid water over the history of the soil from the perspective of the psd lunar regolith rather than terrestrial soil is the best analog to martian soil a globally homogenous soil with such a psd would be an unlikely habitat for the propagation of life on mars

clay minerals of four soils formed in eolian and tephra materials in iceland abstract clay minerals in a vitricryand and three haplocryands derived from eolian and tephra materials in different parts of iceland and in glacial till samples representative of underlying strata were studied by a combination of methods the soils are primarily used as rangelands and are highly susceptible to wind erosion allophanes imogolite and poorly crystalline ferrihydrite are abundant 700 g kg of the clay throughout the soils including a horizons this clay mineralogy would give rise to stable low density aggregates that influence the susceptibility of the soils to wind erosion it also affects chemical properties such as high phosphate retention of the soils even of the cryands with relatively low clay contents 160 275 g kg imogolite was found in some but not all horizons of all soils no particular relationship of imogolite to measured si al molar ratios of the oxalate oxalic acid soluble fractions of the clays 0 51 to 1 13 was evident layer silicate minerals and laminar opaline silicas are either not present or occur in small quantities plagioclase augite and or their weathering residues were found in the clay and silt separates dark colored glass is predominant in the fine sand throughout the soils and the tills one till sample had a clay mineral composition similar to the eolian andic soils while the other contained smectite and possibly a spherical halloysite smectite intermediate but not allophane and imogolite as major weathering products the clay mineral composition of these soils and tills was compared with those derived from basic tephras in other regions

diagnosing the imbalance of glaciar santa rosa cordillera raura peru for glaciar santa rosa in the cordillera raura peru the extent and volume are determined for 1980 and 1961 from topographic mapping and for two undated earlier stages lme and max from moraines the regime of the glacier in terms of ice flow and mass balance is evaluated for the 1977 83 period more than half of the water discharge from the glacier is not renewed by precipitation but supplied by the ice thinning the rate of surface lowering of 2 m a 1 liquid water equivalent corresponds to an energy amount for melting of 22 w m 2 sensitivity analyses of glaciar yanamarey in the nearby cordillera blanca show that such a decrease of energy available for melting could be produced by a cloudiness increase of one tenth an air temperature decrease of more than 2 c a decrease in specific humidity of 1 g kg 1 or some combination of heat budget processes such changes in the atmospheric environment would be required to stabilize the glacier at its recent volume as another indication of the recent imbalance the maximum volume flux is found about 100 m below the equilibrium line altitude under continuation of recent climatic conditions the glacier may disappear within a few decades these inferences corroborate a recent assessment for the neighboring cordillera blanca

orbital identification of carbonate bearing rocks on mars geochemical models for mars predict carbonate formation during aqueous alteration carbonate bearing rocks had not previously been detected on mars surface but mars reconnaissance orbiter mapping reveals a regional rock layer with near infrared spectral characteristics that are consistent with the presence of magnesium carbonate in the nili fossae region the carbonate is closely associated with both phyllosilicate bearing and olivine rich rock units and probably formed during the noachian or early hesperian era from the alteration of olivine by either hydrothermal fluids or near surface water the presence of carbonate as well as accompanying clays suggests that waters were neutral to alkaline at the time of its formation and that acidic weathering proposed to be characteristic of hesperian mars did not destroy these carbonates and thus did not dominate all aqueous environments

basalt weathering and pedogenesis across an environmental gradient in the southern cascade range california usa abstract basalt rocks occupy substantial land area and play a significant role in global weathering patterns and biogeochemical cycling the objective of this research was to quantify climatic controls of weathering and pedogenic processes on basalt derived soils across an environmental gradient on the western slope of the casacade range of california usa we hypothesized that climate controls mineral neogenesis with cool moist conditions favoring formation of short range order sro materials and warm dry conditions favoring smectite crystalline fe oxyhydroxides and kaolins four pedons were sampled across an elevation gradient 250 2500 m having large variation in mean annual soil temperature 5 17 c and mean annual precipitation 750 1350 mm the soil mineral assemblage was characterized by x ray diffraction selective dissolution total elemental analysis and light microscopy the degree of weathering and mineral assemblage exhibited a clear threshold at the permanent winter snowline 1200 m maximum soil development was noted just below the snowline with soils dominated by kaolinite and dehydrated halloysite crystalline fe oxyhydroxides 48 kg m 2 extensive loss of cations chemical index of alteration cia 95 and clay accumulation 447 kg m 2 in contrast the high elevation snow dominated pedons displayed less intense weathering e g cia

silica in a mars analog environment ka u desert kilauea volcano hawaii airborne visible near infrared imaging spectrometer aviris data acquired over the ka u desert are atmospherically corrected to ground reflectance and used to identify the mineralogic components of relatively young basaltic materials including 250 700 and 200 400 year old lava flows 1971 and 1974 flows ash deposits and solfatara incrustations to provide context a geologic surface units map is constructed verified with field observations and supported by laboratory analyses aviris spectral end members are identified in the visible 0 4 to 1 2 m and short wave infrared 2 0 to 2 5 m wavelength ranges nearly all the spectral variability is controlled by the presence of ferrous and ferric iron in such minerals as pyroxene olivine hematite goethite and poorly crystalline iron oxides or glass a broad nearly ubiquitous absorption feature centered at 2 25 m is attributed to opaline amorphous hydrated silica and is found to correlate spatially with mapped geologic surface units laboratory analyses show the silica to be consistently present as a deposited phase including incrustations downwind from solfatara vents cementing agent for ash duricrusts and thin coatings on the youngest lava flow surfaces a second ti rich upper coating on young flows also influences spectral behavior this study demonstrates that secondary silica is mobile in the ka u desert on a variety of time scales and spatial domains the investigation from remote field and laboratory perspectives also mimics exploration of mars using orbital and landed missions with important implications for spectral characterization of coated basalts and formation of opaline silica in arid acidic alteration environments

decadal changes in glacier parameters in the cordillera blanca peru derived from remote sensing we present spatial patterns of glacier fluctuations from the cordillera blanca peru glacier area terminus elevations median elevations and hypsography at decadal timescales derived from 1970 aerial photography 2003 spot5 satellite data geographic information systems gis and statistical analyses we derived new glacier outlines from the 2003 spot images and ingested them in the global land and ice measurements from space glims glacier database we examined changes in glacier area on the eastern and western side of the cordillera in relation to topographic and climate variables temperature and precipitation results include 1 an estimated glacierized area of 569 6 21 km 2 in 2003 2 an overall loss in glacierized area of 22 4 from 1970 to 2003 3 an average rise in glacier terminus elevations by 113 m and an average rise in the median elevation of glaciers by 66 m showing a shift of ice to higher elevations especially on the eastern side of the cordillera and 4 an increase in the number of glaciers which indicates disintegration of ice bodies annual air temperature showed a significant upward trend in the last 30 years with larger temperature increases at lower elevations there was a slight but not significant decrease in precipitation our results are consistent with glacier retreat and warming trends noted in the last three decades in the tropics

weathering sequence of soils from volcanic ash involving allophane and halloysite new zealand abstract the clay minerals in a series of soils from rhyolitic ash having the same stratigraphy but different leaching environments were estimated quantitatively by oxalate dissolution infrared spectroscopy differential thermal analysis electron microscopy and x ray diffraction three soils were studied in detail these were the kereone soil mean annual rainfall 1200 mm the ohaupo soil 1400 mm and the mairoa soil 2600 mm the kereone soil contained halloysite as the predominant clay mineral whereas the mairoa soil was mainly allophanic the ohaupo soil contained considerable amounts of both allophane and halloysite thus the allophane content of the soils increased as rainfall increased reflecting a sequence of increased l leaching the si concentration in soil solution decreased as rainfall increased also reflecting increasing leaching of the soils at mairoa si is rapidly removed and allophane al si 2 1 with monomeric silicate is formed whereas at kereone less leaching occurs si levels are higher and halloysite al si 1 1 with polymeric silicate is formed at intermediate sites either allophane or halloysite may form the often reported situation of younger allophanic beds overlying older 10 000 year halloysitic beds may not be due to allophane weathering to halloysite but may result from lower temperature and drier climate during the last glacial maximum between 10 000 and 26 000 years before present bp a new weathering scheme for volcanic ash in new zealand is presented

historically unprecedented global glacier decline in the early 21st century observations show that glaciers around the world are in retreat and losing mass internationally coordinated for over a century glacier monitoring activities provide an unprecedented dataset of glacier observations from ground air and space glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass balance data relating to the impact that glaciers exercise on global sea level fluctuations or on regional runoff in this study we provide an overview and analysis of the main observational datasets compiled by the world glacier monitoring service wgms the dataset on glacier front variations 42000 since 1600 delivers clear evidence that centennial glacier retreat is a global phenomenon intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the little ice age or holocene glaciological and geodetic observations 5200since 1850 show that the rates of early 21st century mass loss are without precedent on a global scale at least for the time period observed and probably also for recorded history as indicated also in reconstructions from written and illustrated documents this strong imbalance implies that glaciers in many regions will very likely suffer further ice loss even if climate remains stable

sensitivities of the equilibrium line altitude to temperature and precipitation changes along the andes abstract equilibrium line altitudes elas of alpine glaciers are sensitive indicators of climate change and have been commonly used to reconstruct paleoclimates at different temporal and spatial scales however accurate interpretations of ela fluctuations rely on a quantitative understanding of the sensitivity of elas to changes in climate we applied a full surface energy and mass balance model to quantify ela sensitivity to temperature and precipitation changes across the range of climate conditions found in the andes model results show that ela response has a strong spatial variability across the glaciated regions of south america this spatial variability correlates with the distribution of the present day mean climate conditions observed along the andes we find that elas respond linearly to changes in temperature with the magnitude of the response being prescribed by the local lapse rates ela sensitivities to precipitation changes are nearly linear and are inversely correlated with the emissivity of the atmosphere temperature sensitivities are greatest in the inner tropics precipitation becomes more important in the subtropics and northernmost mid latitudes these results can be considered an important step towards developing a framework for understanding past episodes of glacial fluctuations and ultimately for predicting glacier response to future climate changes