photogeologic analysis of impact melt rich lithologies in kepler crater that could be sampled by future missions 1 kepler is a 31 km diameter copernican age complex impact crater located on the nearside maria of the moon we used lunar reconnaissance orbiter imagery and topographic data in combination with kaguya terrain camera and other image data sets to construct a new geomorphologic sketch map of the kepler crater with a focus on impact melt rich lithologies most of the interior melt rocks are preserved in smooth and hummocky floor materials smaller volumes of impact melt were deposited in rim veneer interior and exterior ponds and lobe like overlapping flows on the upper crater wall based on shadow lengths typical flows of melt rich material on crater walls and the western rim flank are 1 5 m thick and have yield strengths of 1 10 kpa the melt rock distribution is notably asymmetric with interior and exterior melt rich deposits concentrated north and west of the crater center this melt distribution and the similarly asymmetric ray distribution imply a slightly less than 45 impact trajectory from the southeast the exposed wall of kepler displays distinct layering with individual layers having typical thicknesses of 3 5 m these are interpreted as flows of procellarum mare basalts in the impact target from the point of view of exploration numerous fractures and pits in the melt rich floor materials not only enable detailed studies of melt related processes of impact crater formation but also provide potential shelters for longer duration manned lunar missions

delta progradation and neoglaciation laguna paron cordillera blanca peru the history of holocene glaciation serves as an important record of glacier mass balance and therefore of climatic change the moraine record of holocene glaciation in the tropical andes however is fragmentary and poorly dated in contrast increases in the rate of accumulation of inorganic sediment in glacier fed lakes have been linked to periods of neoglaciation in many mountain regions the interpretation of such a record of neoglaciation from sediment cores in glacier fed lakes in the tropical andes can provide the continuity and chronologic control that is lacking in the existing moraine record unusual exposures of glacial lacustrine sediment in the cordillera blanca peru provide a rare opportunity to assess the link between climatic change glaciation and lacustrine sedimentation intentional lowering of water levels in laguna paron 9 s 77 44 w 4200 m a s l in 1985 resulted in the incision and exposure of at least 20 m of deltaic deposits at the eastern end of the lake three deltaic units can be identified horizontal topset beds steeply dipping and deformed foreset beds and horizontally laminated fine grained sediment six radiocarbon ages ranging from 1800 210 to 465 95 14c yr bp on wood indicate that the average rate of delta progradation in the late holocene has been approximately 290 m per 1000 yr the lake formed during deglaciation at least 10 000 yr ago and if such a rate of progradation of the delta had prevailed over the entire holocene then the delta would be at least three times as extensive as it is today thus the rate of delta progradation has varied significantly over the holocene we suggest that the rate of delta progradation was at least three times greater when glaciers were in advanced positions these positions are clearly delimited by neoglacial moraines which are within 1 2 km of the exposures studied and within 1 km of modern ice limits the most recent increase in the rate of delta progradation is evidenced by an increase in sedimentation rate ca 575 90 14c yr bp coincident with the onset of the little ice age copyright 2005 john wiley sons ltd

decadal evolution of a very small heavily debris covered glacier in an alpine permafrost environment glacier response to climate forcing can be heterogeneous and complex depending on glacier system characteristics this article presents the decadal evolution of the tsarmine glacier swiss alps a very small and heavily debris covered cirque glacier located in the alpine periglacial belt archival aerial photogrammetry and autocorrelation of orthophotos were used to compute surface elevation volume and geodetic mass changes as well as horizontal displacement rates for several periods between 1967 and 2012 a gpr survey allowed us to investigate glacier thickness 15 m mean and volume 4 10 6 m 3 in 2015 and to anticipate its future evolution different dynamics occurred in recent decades because of the heterogeneous surface characteristics the climate sensitive upper debris free zone contrasts with the progressively stagnant heavily debris covered glacier tongue between 1967 and 2012 the glacier lost 1 3 of its initial volume 2 10 6 m 3 the average mass balance stabilised at 0 3 m w e a 1 since 1999 compared with other local glaciers the tsarmine glacier shows a particular decadal behaviour both in time divergence of mass balance since the 2000s and space inverted ablation pattern this might be explained by the combined influence of debris cover shadow snow redistribution and permafrost conditions on this very small glacier

satellite sar interferometry for the improved assessment of the state of activity of landslides a case study from the cordilleras of peru abstract in peru landslides have been causing damages and casualties annually due to the high mountain relief and distinct seasonal precipitation distribution satellite synthetic aperture radar sar interferometry represents one possibility for mapping surface deformation at fine spatial resolution over large areas in order to characterize aspects of terrain motion and potentially hazardous processes we present land surface motion maps derived from satellite sar interferometry insar for a part of the santa river basin between the cordilleras blanca and negra around the city of carhuaz in peru using both persistent scatterer interferometry psi and differential sar interferograms dinsar from alos 1 palsar 1 envisat asar alos 2 palsar 2 and sentinel 1 we mapped 42 landslides extending over 17 190 141 m2 within three classes of activity i e 0 2 cm a 2 10 cm a and 10 cm a a geomorphological inventory of landslides was prepared from optical satellite imagery and field experience and compared to the insar based slope instability inventory the two approaches provide slightly different information about landslide spatial and temporal activity patterns but altogether they can be combined for the assessment of the state of activity of landslides and possibly the development of hazard maps which are not systematically available in this region we conclude that alos palsar 1 and 2 and sentinel 1 data have a high potential to derive high quality surface deformation information of landslides in many mountainous regions worldwide due to their global and frequent acquisition strategies

the nature of crater rays the copernicus example crater rays are formed during a cratering event as target material is ballistically ejected to distances of many crater radii forming narrow generally high albedo approximately linear features extending outward from the crater the nature of crater rays was examined for the lunar crater copernicus using new information on the composition of surface material from near ir reflectance measurements surface roughness from radar backscatter measurements and photogeologic data from available images part of the data analysis included use of mixing models to quantify the mixing systematics observed between primary ejecta and local substrate of the ray on the basis of compositional parameters from reflectance spectra primary material from copernicus can be detected in the surface material of rays in decreasing amounts with increasing radial distance e g 20 25 primary ejecta at six crater radii for distances greater than three crater radii the proportion of local material to primary ejecta observed from these compositional reflectance data is approximately equal to that predicted by previous laboratory and ballistic studies of craters within three crater radii the compositional data indicate a higher proportion of primary ejecta than predicted for extended areas along the ray that do not contain large secondary craters the primary ejecta is intimately mixed on the granular scale with local material throughout the regolith the relatively high albedo of the rays of copernicus is due to the feldspathic composition highland of the primary ejecta in rays emplaced on a mare substrate immature local substrate is only observed in copernicus s ray at large unmantied secondary craters or other areas with sufficient topographic slope to prevent the accumulation of mature soils crater rays are filamentous generally high albedo features that emanate nearly radially from young impact structures rays are narrow in relation to the crater radius extend distally for many crater radii and constitute a distinctive albedo feature around some of the largest and freshest lunar craters visible from earth synoptic views of ray systems figure la give the strong impression that the rays comprise bright material that has been excavated from the crater cavity and been emplaced beyond the continuous ejecta deposit if this visual impression is correct then the process that forms crater rays represents a significant mechanism for the lateral transport of primary material to great distances from its point of origin and particularly for craters larger than a let tens of kilometers in diameter constitutes a fundamental process for the regional mixing of crustal materials earth based telescopic images of the moon allowed the first studies and descriptions of rays and ray systems shoemaker 1962 described the arcuate and loop shaped streaks of the copernicus ray systems and showed that these patterns could be locally resolved into individual en echelon feather shaped elements 15 20 km in length with their long axes oriented approximately radially to the crater he noted the presence of elongate depressions or gouges in the ray system ranking in diameter from 8 km down to the limits of resolution and generally located at the proximal ends of the individual ray elements shoemaker observed that some of the gouges were

hummocky moraines in the namaras and susam valleys central taurids sw turkey abstract late quaternary glacial features have been found in the central taurid mountains in u shaped valleys located at an altitude of more than 2000 m and surrounded by mountain ranges reaching 2850 m no present day active glaciers exist in this area where the snowline elevation lies at about 3500 m the namaras valley and its tributary susam valley are characterized by coarse loose material forming chaotic knob and kettle topography mounds 1 10 m high and 10 30 m wide are separated by 5 30 m wide several meters deep irregular depressions the upper surfaces of the mounds are covered by angular to subangular limestone pebbles and blocks and internal sediments show a typical diamicton appearance with pebbles suspended in a muddy to sandy matrix these chaotic structures are interpreted as hummocky disintegration moraines from former active glaciers successive cross valley morainic ridges up to 200 m high and several hundreds of meters long limit the down valley extension of these hummocks and are interpreted as ice marginal moraines in the tributary susam valley part of the coarse loose material forms a 200 250 m long and 90 120 m wide tongue shaped structure with successive arcuate ridges and furrows at its down valley reach this structure which is connected upward to a talus slope and perched cirque ressembles the morphology of a periglacial rockglacier but is interpreted as the disintegration moraine controlled by small periodic retreat and readvance of the last active ice front in this region

major lunar crustal terranes surface expressions and crust mantle origins in light of global remotely sensed data the igneous crust of the moon can no longer be viewed as a simple globally stratified cumulus structure composed of a flotation upper crust of anorthosite underlain by progressively more mafic rocks and a residual melt kreep sandwich horizon near the base of the lower crust instead global geochemical information derived from clementine multispectral data and lunar prospector gamma ray data reveals at least three distinct provinces whose geochemistry and petrologic history make them geologically unique 1 the procellarum kreep terrane pkt 2 the feldspathic high lands terrane fht and 3 the south pole aitken terrane spat the pkt is a mafic province coincident with the largely resurfaced area in the procellarum imbrium region whose petrogenesis relates to the early differentiation of the moon here some 40 of the th in the moon s crust is concentrated into a region that constitutes only about 10 of the crustal volume this concentration of th average 5 ppm and by implication the other heat producing elements u and k led to a fundamentally different thermal and igneous evolution within this region compared to other parts of the lunar crust lower crustal materials within the pkt likely interacted with underlying mantle materials to produce hybrid magmatism leading to the magnesian suite of lunar rocks and possibly kreep basalt although rare in the apollo sample collection widespread mare volcanic rocks having substantial th enrichment are indicated by the remote data and may reflect further interaction between enriched crustal residues and mantle sources the fht is characterized by a central anorthositic region that constitutes the remnant of an anorthositic craton resulting from early lunar differentiation basin impacts into this region do not excavate significantly more mafic material suggesting a thickness of tens of kilometers of anorthositic crust the feldspathic lunar meteorites may represent samples from the anorthositic central region of the fht ejecta from deep penetrating basin impacts outside of the central anorthositic region however indicate an increasingly mafic composition with depth the spat a mafic anomaly of great magnitude may include material of the upper mantle as well as lower crust thus it is designated a separate terrane whether the spa basin impact simply uncovered lower crust such as we infer for the fht remains to be determined

from the imbrium basin to crater tycho the first regional spectral distribution map derived from sir 2 near infrared data abstract near infrared nir data obtained at the moon by the sir 2 instrument aboard chandrayan 1 have been analyzed and classified according to their spectral absorption characteristics this approach yielded a new nir map based on 10 spectral categories that we have identified which cover a substantial portion of the lunar nearside the inferred distribution of materials that share similar reflectance patterns resembles existing geologic maps where were drawn using a range of complementary methods but differs from these in respect of detailed structures in particular new features were found in the distributions of mare flows within the imbrium basin as well as across boundary regions and in circumbasin formations which lead to new geological interpretations a new map of crater tycho and its surroundings was in addition constructed based on eight spectral types differentiated between ejected materials and crater infill

chronological and geomorphological investigation of fossil debris covered glaciers in relation to deglaciation processes a case study in the sierra de la demanda northern spain abstract in this study fossil debris covered glaciers are investigated and dated in the sierra de la demanda northern spain they are located in glacial valleys of approximately 1 km in length where several moraines represent distinct phases of the deglaciation period several boulders in the moraines and fossil debris covered glaciers were selected for analysis of 10 be surface exposure dating a minimum age of 17 8 2 2 ka was obtained for the outermost moraine in the san lorenzo cirque and was attributed to the global last glacial maximum lgm or earlier glacial stages based on deglaciation dates determined in other mountain areas of northern spain the youngest moraines were dated to approximately 16 7 1 4 ka and hence correspond to the gs 2a stadial oldest dryas given that the debris covered glaciers fossilize intermediate moraines it was deduced that they developed between the lgm and the oldest dryas coinciding with a period of extensive deglaciation during this deglaciation phase the cirque headwalls likely discharged large quantities of boulders and blocks that covered the residual ice masses the resulting debris covered glaciers evolved slowly because the debris mantle preserved the ice core from rapid ablation and consequently they remained active until the end of the late glacial or the beginning of the holocene for the san lorenzo cirque and the holocene thermal maximum for the mencilla cirque the north facing part of the mencilla cirque ensured longer preservation of the ice core

subdivision of late pleistocene moraines in the cordillera blanca peru based on rock weathering features soils and radiocarbon dates abstract the progressive development of unusual rock weathering features and soils and minimum limiting radiocarbon dates provide a basis for subdividing four groups of late pleistocene moraines on the west side of the cordillera blanca northern peru 9 20 1 000 s 77 10 77 30 w boulders on the youngest late pleistocene moraines have 10 to 14 cm tall weathering posts soils on these moraines yield mean profile development index pdi values of 0 05 0 04 1 these moraines date between ca 13 500 and 9700 500 yr b p older than previously postulated the next older moraines have boulders with weathering post heights between 20 and 25 cm and soils with pdi values of 0 08 0 07 and were deposited prior to 13 280 190 yr b p probably during the last glacial maximum marine isotope stage 2 moraines from an older glaciation have boulders with weathering posts between 39 and 50 cm high soils that yield pdi values of 0 21 0 07 and are older than 19 700 340 yr b p boulders on moraines from a still older glaciation have lost ca 50 of their above ground volume and have weathering posts between 62 and 70 cm high pdi values for soils on these moraines are 0 32 0 06 linear and logarithmic models of weathering post and soil development with time are used to estimate minimum and maximum ages for the two oldest moraine groups linear models suggest that the second oldest moraines are between ca 20 500 and 46 500 yr b p and that the oldest moraines are between ca 29 000 and 72 000 yr b p in contrast logarithmic models suggest ages of greater than ca 75 500 yr b p and greater than ca 500 000 yr b p respectively

petrology of impact melt rocks at the chicxulub multiring basin yucatan mexico compositions and textures of melt rocks from the upper part of the chicxulub structure are typical of melt rocks at other large terrestrial impact structures apart from variably elevated iridium concentrations less than 1 5 to 13 5 0 9 ppb indicating nonuniform dissemination of a meteoritic component bulk rock and phenocryst compositions imply that these melt rocks were derived exclusively from continental crust and platform sediment target lithologies modest differences in bulk chemistry among samples from wells located approximately 40 km apart suggest minor variations in relative contributions of these target lithologies to the melts subtle variations in the compositions of early formed pyroxene and plagioclase also support minor primary differences in chemistry between the melts evidence for pervasive hydrothermal alteration of the porous mesostasis includes albite k feldspar quartz epidote chlorite and other phyllosilicates as well as siderophile element enriched sulfides suggesting the possibility that chicxulub like sudbury may host important ore deposits

the clementine mission to the moon scientific overview in the course of 71 days in lunar orbit from 19 february to 3 may 1994 the clementine spacecraft acquired just under two million digital images of the moon at visible and infrared wavelengths these data are enabling the global mapping of the rock types of the lunar crust and the first detailed investigation of the geology of the lunar polar regions and the lunar far side in addition laser ranging measurements provided the first view of the global topographic figure of the moon the topography of many ancient impact basins has been measured and a global map of the thickness of the lunar crust has been derived from the topography and gravity

the capillary fringe and its effect on water table response abstract shallow water tables are often observed to respond in a highly disproportionate manner to precipitation events that is the magnitude of the response is often much greater than would be predicted on the basis of the specific yield of the geologic material and the amount of rainfall physical arguments are presented to show that if the capillary fringe the zone of tension saturation extends to ground surface then the addition of a very small amount of water can result in an immediate and large rise in the water table the arguments are supported by a field experiment in which the addition of 0 3 cm of water caused the water table to rise 30 cm in 0 25 min thus demonstrating the large and highly transient influence of the capillary fringe on the position of the water table the evidence in this study as well as recent work of others suggests that the capillary fringe effect could have a major influence on the process of stream flow generation contaminant transport to surface waters and contaminant transport in hydrogeologic regimes having shallow water tables it is further shown that calculations of groundwater recharge and consumptive use based on water table response and an assumed specific yield could be substantially in error

slow dynamics in debris covered and rock glaciers in hofsdalur trollaskagi peninsula northern iceland abstract the results of previous work on the dynamics of the debris covered and rock glaciers in trollaskagi are contradictory to improve our knowledge of these dynamics and determine the origin and evolution of these landforms we analyzed two case studies located in the hofsdalur valley the hofsjokull debris covered glacier and the jullogil rock glacier using digital photogrammetry combined with gis techniques our most accurate results were obtained for the period 1980 1994 as follows for the hofsjokull debris covered glacier a mean block displacement velocity of 0 22 m yr 1 a block elevation difference of 0 36 m and a horizontal displacement of linear ridges of 0 21 m yr 1 for the jullogil rock glacier a mean block displacement velocity of 0 15 m yr 1 a block elevation difference of 0 63 m and a horizontal displacement of linear ridges of 0 16 m yr 1 the limits of these glaciers remained stable for 70 years from 1946 to 2017 all our data support the fact that these landforms are stable and having lost their ice accumulation sources their dynamics are fundamentally related to subsidence processes therefore they are relict landforms whose origin seems to be related to paraglacial processes after rapid deglaciation of the valleys and their stagnated ice is preserved as it is above the permafrost level

paleoseismicity and neotectonics of the cordillera blanca fault zone northern peruvian andes the cordillera bianca fault zone is a major west dipping normal fault that bounds the west side of a 120 to 170 km wide zone of active extension along the crest of the northern peruvian andes the fault is approximately 210 km long and exhibits continuous geomorphic evidence of repeated late pleistocene and holocene displacements but has not been the source of historical or teleseismically recorded earthquakes trenching and mapping of fault scarps provide new information on earthquake recurrence slip rate timing of the most recent events and andean neotectonics at quebrada queroccocha 55 km from the south end of the zone an 11 000 to 14 000 year old moraine is displaced 12 15 m and younger valley fill lacustrine and fluvial deposits are displaced 7 5 8 m scarp profiles tectonic terraces and trench exposures indicate five to seven scarp forming earthquakes of 2 3 m per event during the past 11 000 14 000 years at this location considering uncertainties in the number of events and in the age of the displaced moraine the average recurrence interval is estimated to be 2440 1060 years detrital charcoal from colluviums that predate and postdate the most recent event yielded ages of 2480 65 and 750 80 14c years b p respectively and stratigraphic relationships suggest that the event may be closer to the older date the late quaternary slip rate at quebrada queroccocha is 0 86 1 36 mm yr and appears to be representative of much of the fault zone at pachma bajo located 30 km from the north end of the zone on a separate segment displacement during each of the past two events was 2 to 3 m the morphology of scarps in alluvial fan and debris flow deposits indicates recurrence intervals of about 1000 3000 years relationships between pre inca walls and faulted deposits suggest that 1500 2000 years have elapsed since the most recent event fault behavior parameters particularly displacement per event and fault segment length show that the cordillera bianca fault zone is similar to seismogenic normal faults that nucleate m 7 7 earthquakes at depths of approximately 15 km the quebrada queroccocha slip rate and analysis of other normal faults in the region suggest cumulative late quaternary extensional strain rates of about 1 4 mm yr across the complete zone of andean crestal extension

scaling impact melting and crater dimensions implications for the lunar cratering record abstract the dimensions of large craters formed by impact are controlled to a large extent by gravity whereas the volume of impact melt created during the same event is essentially independent of gravity this differential scaling fosters size dependent changes in the dynamics of impact crater and basin formation as well as in the final morphologies of the resulting structures a variety of such effects can be observed in the lunar cratering record and some predictions can be made on the basis of calculations of impact melting and crater dimensions among them are the following 1 as event magnitude increases the volume of melt created relative to that of the crater will grow and more will be retained inside the rim of the crater or basin 2 the depth of melting will exceed the depth of excavation at diameters that essentially coincide with both the inflection in the depth diameter trend and the simple to complex transition 3 the volume of melt will exceed that of the transient cavity at a cavity diameter on the order of the diameter of the moon this would arguably correspond to a moon melting event 4 small lunar craters only rarely display exterior flows of impact melt because the relatively small volumes of melt created can become choked with clasts increasing the melt s viscosity and chilling it rapidly larger craters and basins should suffer little from such a process 5 deep melting near the projectile s axis of penetration during larger events will yield a progression in cen tral structure morphology with growing event magnitude this sequence should range from single peaks through multiple peaks to peak rings 6 the minimum depth of origin of central peak material should co incide with the maximum depth of melting the main central peak in a crater the size of tycho should have had a preimpact depth of close to 15 km

response of debris covered glaciers in the mount everest region to recent warming and implications for outburst flood hazards abstract in areas of high relief many glaciers have extensive covers of supraglacial debris in their ablation zones which alters both rates and spatial patterns of melting with important consequences for glacier response to climate change wastage of debris covered glaciers can be associated with the formation of large moraine dammed lakes posing risk of glacier lake outburst floods glofs in this paper we use observations of glaciers in the mount everest region to present an integrated view of debris covered glacier response to climate change which helps provide a long term perspective on evolving glof risks in recent decades debris covered glaciers in the everest region have been losing mass at a mean rate of 0 32 m yr 1 although in most cases there has been little or no change in terminus position mass loss occurs by 4 main processes 1 melting of clean ice close to glacier elas 2 melting beneath surface debris 3 melting of ice cliffs and calving around the margins of supraglacial ponds and 4 calving into deep proglacial lakes modelling of processes 1 and 2 shows that everest region glaciers typically have an inverted ablation gradient in their lower reaches due to the effects of a down glacier increase in debris thickness mass loss is therefore focused in the mid parts of glacier ablation zones causing localised surface lowering and a reduction in downglacier surface gradient which in turn reduce driving stress and glacier velocity so the lower ablation zones of many glaciers are now stagnant model results also indicate that increased summer temperatures have raised the altitude of the rain snow transition during the summer monsoon period reducing snow accumulation and ice flux to lower elevations as downwasting proceeds formerly efficient supraglacial and englacial drainage networks are broken up and supraglacial lakes form in hollows on the glacier surface ablation rates around supraglacial lakes are typically one or two orders of magnitude greater than sub debris melt rates so extensive lake formation accelerates overall rates of ice loss most supraglacial lakes are perched above hydrological base level and are susceptible to drainage if they become connected to the englacial drainage system speleological surveys of conduits show that large englacial voids can be created by drainage of warm lake waters along pre existing weaknesses in the ice roof collapses can open these voids up to the surface and commonly provide the nuclei of new lakes thus by influencing both lake drainage and formation englacial conduits exert a strong control on surface ablation rates an important threshold is crossed when downwasting glacier surfaces intersect the hydrological base level of the glacier base level lakes formed behind intact moraine dams can grow monotonically and in some cases can pose serious glof hazards glacier termini can evolve in different ways in response to the same climatic forcing so that potentially hazardous lakes will form in some situations but not others additionally the probability of a flood is not simply a function of lake volume but depends on the geometry and structure of the dam and possible trigger mechanisms such as ice or rockfalls into the lake satellite based measurements of glacier surface gradient and ice velocities allow probable future locations of base level lakes to be identified a base level lake has begun to grow rapidly on ngozumpa glacier west of mount everest and could attain a volume of 10 8 m 3 within the next 2 or 3 decades unless mitigation efforts are undertaken this lake could pose considerable glof hazard potential

logistic regression modeling of rock glacier and glacier distribution topographic and climatic controls in the semi arid andes abstract logistic regression is applied to a random sample of surface points in the semi arid andes of santiago and mendoza chile argentina 32 45 34 30 s 12 000 km 2 above 3000 m a s l to identify local and regional controls on rock glacier and glacier distribution the study area is among the areas with the greatest abundance of rock glaciers worldwide the explanatory variables used for model selection are related to local and regional morphometric and climatic characteristics the models achieve a very good fit area under the roc curve 0 84 for rock glaciers and 0 95 for glaciers and are able to reproduce the regional distribution pattern model results are used to determine the optimal morphographic and climatic niche of rock glaciers and glaciers in the study area and help explain the presence of low elevation rock glaciers under favorable topoclimatic conditions

mapping iron in the lunar mare an improved approach 1 previous methods for mapping iron lucey et al 1995 1998 2000a give inconsistent results in terms of suppressing the effects of maturity making it difficult to distinguish true units of contrasting iron from regions that simply show the residual effects of incomplete separation of maturity these methods rely on an assumption that materials of similar iron content but varying maturity form radial trends on a plot of vis reflectance versus nir vis ratio recently the assumption of radial behavior of maturity trends in mare regions has been called into question by staid and pieters 2000 they observed trends in the mare that appeared more parallel in nature in this work we study nearly 10 000 craters in six mare regions and model the effects of maturity with radiative transfer theory to quantify and better understand the spectral behavior of maturity variations in the mare we confirm that the maturity trends in mare regions are more parallel than radial and we exploit this fact to develop a new algorithm for determination of iron content in mare regions this new mare iron algorithm better compensates for maturity than previous methods and uncertainties due to maturity variations are less than 0 5 wt feo absolute uncertainties are similar to previous algorithms 1 5 wt feo results from this work provide the ability to detect iron anomalies in the ejecta of craters and as a result more confidently map vertical stratigraphy in the lunar mare in terms of iron composition

pyroxene spectroscopy revisited spectral compositional correlations and relationship to geothermometry the authors wish to thank the various agencies which have provided the necessary support for this project including grants in aid of research from sigma xi the scientific research society to e a c the geological society of america grant 3741 87 to e a c and nasa planetary geology and geophysics grant nagw 642 to m j g

recent evolution and degradation of the bent jatunraju glacier cordillera blanca peru abstract this article brings new insight into the recent evolution and degradation of the bent jatunraju glacier in the northern part of the cordillera blanca peru analysis of topographical maps aerial photos and satellite images covering a period of 66 years and a field survey performed in june 2013 and may 2014 helped to describe the geomorphological setting and ongoing processes recent evolution and degradation processes are also deduced from surface movements historical geodetic measurements 1967 1968 1977 1984 and current landsat images 2001 2013 were used to estimate surface velocities and changes in surface velocities over time our investigation showed that the most significant changes happened at an altitude of between 4300 and 4450 m asl a significant decrease in surface velocities and increase in debris thickness indicate that this part of jatunraju turned from a debris covered glacier into an ice cored rock glacier during the analyzed period particular parts of the article describe the cycle of formation and extinction of supraglacial lakes and the melting of buried debris covered ice a scenario of future evolution is outlined and discussed as well we assume that ice degradation within the debris covered glacier will continue and that the altitude of its presence will increase hand in hand with the changing environment

the genesis and significance of hummocky moraine evidence from the isle of skye scotland abstract the range of genetic and climatic interpretations of scottish hummocky moraine is reviewed and new data are presented from the isle of skye western scotland which are used as the basis of a genetic classification hummocky moraine on skye is shown to consist of three principal sediment landform associations 1 recessional moraines 2 chaotic ice stagnation moraines and 3 drumlins and fluted moraines the recessional moraines consist of transverse moraine ridges and chains of mounds and were formed by a combination of glaciotectonics and debris accumulation at active ice margins second chaotic moraines consist of randomly distributed hummocks mounds and rim ridges and record deposition in contact with inactive ice finally drumlins and fluted moraines are longitudinally oriented subglacial bedforms formed by a combination of lodgement and sediment deformation individual occurrences of hummocky moraine may comprise one two or all of these associations the detailed study and differentiation of scottish hummocky moraine provides a valuable source of information on former glacier dynamics and landscape change

the identification of runoff production mechanisms using environmental isotopes in a tussock grassland catchment eastern otago new zealand a previous hydrometric study of runoff production in tussock grassland drainage basins in otago 45 50 s 169 45 e new zealand revealed a marked change of slope in storm hydrograph recessions an environmental isotope study was initiated to investigate the runoff mechanisms operating and to test specific hypotheses to explain this break in the hydrograph recession the results indicated that for quickflow volumes in excess of 10mm the first part of the storm hydrograph can be attributed to two separate sources namely old water from a shallow unconfined groundwater reservoir and new water from saturation overland flow on the lower wetlands of concave slopes despite the extensive area of wetlands old water runoff from the unconfined groundwater reservoir is delivered more rapidly to the stream than new water from saturation overland flow substantial surface storage in the wetlands has first to be exceeded before rain becomes a significant part of stream discharge for quickflow volumes less than 10mm only old water from groundwater contributes to the first part of the hydrograph recession this means that only the largest 7 per cent of storms in terms of quickflow volume generate quickflow containing significant amounts of new water the second part of the recession of the storm hydrograph consists of old water derived from a remarkably well mixed shallow unconfined groundwater body

sedimentation in glacial environments and the identification of tills and tillites in ancient sedimentary sequences abstract tills and tillites are defined and subdivided into primary tills comprising lodgement tills melt out tills and sublimation tills and secondary tills comprising flow tills and deformation tills they are defined on the basis of their mode of deposition which endows them with their distinctive properties another category of till that of supra till is defined on the basis of its debris source derived supraglacially from valley sides and nunataks which gives these tills a coarse grained character the processes of till deposition and of outwash sedimentation are associated in several recurrent combinations which allow the definition of three principal glacial sediment associations and land systems which define the character of the sequences within which tills tend to occur the criteria which allow tills of different genesis to be identified and to be distinguished from non till diamictons are reviewed there are several features which are uniquely characteristic of till but unfortunately these are few it has been found generally necessary to employ an array of characteristics which though not individually unique to till when taken together can be strong evidence for particular till types the recognition of several typical and repetitive facies sequences which form in the major glacial sedimentary environments can also be important indicators of till genesis

cometary and meteorite swarm impact on planetary surfaces the velocity flow fields energy partitioning and ejecta distributions resulting from impact of porous fragmented icy cometary nuclei with silicate planetary surfaces at speeds from 5 to 45 km s are different than those resulting from the impact of solid ice or silicate meteorites the impact of 1 g cm 3 ice spheres onto an atmosphereless anorthosite planetary surface induces cratering flows that appear similar to those induced by normal density anorthosite meteorite impact both of these impactors lead to deep transient crater cavities for final crater diameters less than 1 to 10 km and for escape velocities 10 5 cm s moreover the fraction of internal energy partitioned into the planetary surface at the cratering site is 0 6 for both ice and anorthosite impactors at 15 km s as the assumed density of the hypothetical cometary nucleus or fragment cloud from a nucleus decreases to 0 01 g cm 3 the fraction of the impact energy partitioned into planetary surface internal energy decreases to less than 0 01 and the flow field displays a toroidal behavior in which the apparent source of the flow appears to emanate from a disc or ringlike region rather than from a single point as in the explosive cratering case the edges of the crater region are in several cases depressed and flow downward whereas the center of the crater region is uplifted moreover the resultant postimpact particle velocity flow in some cases indicates the formation of concentric ridges a central peak and a distinct absence of a deep transient cavity in contrast transient cavities are a ubiquitous feature of nearly all previous hypervelocity impact calculations the calculations of the flow fields for low density 0 01 g cm 3 impactors exhibited surface interface comet planet instabilities these are attributed to both the rayleigh taylor and helmholtz instability conditions and we believe that these occur in all flows involving volatile low density 0 01 g cm 3 projectiles it is speculated that these hydrodynamic instabilities can give rise to concentric rings in the inner crater region in large scale impacts on planetary surfaces although other mechanisms for their production may also act the ejecta mass loss versus planetary escape velocity was computed and these results imply that the critical escape velocity at which as much material is lost as is being accreted from a planet ranges from 1 2 to 2 75 km s for encounter speeds of 5 to 15 kms s with cometary impactors having a density of 0 01 to 1 g cm 3 these values compare to 0 83 and 1 5 km s for silicate impactors thereby indicating that it is more difficult for volatiles than silicates to be accreted onto objects with escape velocities similar to the moon mercury and mars for objects with escape velocities in the 0 1 to 1 km s range the accretional efficiency for silicate and various porosity ices are similar whereas for objects with escape velocities 0 1 km s the accretional efficiency of icy impactors becomes significantly lower than for silicate impactors

ice core palaeoclimate records in tropical south america since the last glacial maximum ice core records spanning the last 25 000 yr from the tropical andes of south america are reviewed these records from quelccaya huascaran and sajama present a high temporal resolution picture of both the late glacial stage lgs and the holocene climatic and environmental conditions in the south american andes late glacial stage conditions at high elevations appear to have been cooler than today although the magnitude of the inferred cooling differs with the particular proxy used e g snowline depression pollen ice cores insoluble dust and anion concentrations in the ice cores reveal that lgs hydrological conditions in the tropics 9 s were much drier than today whereas in the subtropics 18 s lgs conditions were much wetter this probably reflects the migration of the tropical hadley cell in response to a different meridional temperature gradient low nitrate concentrations in the lgs ice from both huascaran and sajama suggest that the amazon basin forest cover may have been much less extensive discussed is the conundrum surrounding the use of d 18 o as a palaeothermometer in the tropics where temperatures exhibit little seasonal variation yet the ice core records suggest that d 18 o records temperature variations on decadal to millennial time scales finally evidence is presented for a strong twentieth century warming copyright 2000 john wiley sons ltd

the distribution of olivine in the crater copernicus we employed multispectral imaging in the visible and near ir at four wavelengths 0 73 0 96 1 45 and 1 99 m of copernicus crater in order to map the distribution of olivine rich pyroxene poor material known previously to occur in the central peak complex we identified three additional portions of the crater to exhibit spectral characteristics similar to those of the central peaks strongly suggesting the presence of material similar to that exposed in the central peaks these areas are a scarp forming a portion of the northern rim of copernicus and two slump blocks in the north wall which may have been derived from the same portion of the ejecta now exposed in the rim scarp these occurrences decrease the minimum allowable depth for this unusual material in the copernicus target site though still represent some of the deepest material exposed by copernicus

the geomorphic significance of rock glaciers estimates of rock glacier debris volumes and headwall recession rates in west greenland to obtain knowledge on rockwall retreat rates at sites with rock glaciers an inventory of about 400 individual rock glacier sites in west greenland was carried out by means of field studies and using aerial photographs and topographic maps a number of sites with ice cored moraines beyond normal glaciers were included in the analysis for comparative purposes the estimated debris volume was compared with the size of the source headwall the result of the inventory suggests that the presence of rock glaciers indicates extraordinary high retreat rates for rock free faces above especially headwalls above glacier derived rock glaciers are exposed to high weathering rates and thereby presumably delimit critical ranges regarding altitude for headwall retreat rates the relation of such a critical altitudinal range to other regional concepts such as glaciation level gl and glacier equilibrium line is discussed from this comments are also made on the relation between various permafrost zones and the typical regional climate within the maximum headwall weathering altitude at sites with active rock glaciers finally the potential importance of this range of maximum weathering for understanding the long term evolution of high relief cold climate landscapes is emphasised

the timing and magnitude of mountain glaciation in the tropical andes the andes of ecuador peru and bolivia host the majority of the world s tropical glaciers in the tropical andes glaciers accumulate during the wet season austral summer and ablate year round precipitation is delivered mainly by easterlies and decreases both n s and e w chronological control for the timing of glacial advances in the tropical andes varies in ecuador six to seven advances have been identified dating is based on radiocarbon ages timing of the local last glacial maximum lgm and the existence of younger dryas advances remain controversial in peru local variability in glaciation patterns is apparent surface exposure dating in the cordillera blanca and junin plain suggests that the local lgm may have been early 30 ka although uncertainties in age calculations remain the local lgm was followed by a lateglacial readvance stillstand and preceded by larger glaciations in contrast preliminary data from an intervening massif indicate that the largest moraines are lateglacial chronologies from bolivia also suggest local variability in leeward milluni and san francisco valleys local lgm moraines descend to 4300 m above sea level a s l whereas in windward zongo valley lateglacial moraines reach 3400 m a s l atlantic and pacific sea surface temperatures el nino southern oscillation and insolation changes all likely play roles in mediating tropical andean glacial cycles copyright 2008 john wiley sons ltd additional supporting information may be found in the online version of this article

large mineralogically distinct impact melt feature at copernicus crater evidence for retention of compositional heterogeneity 1 despite several lines of evidence for efficient mixing of impact melt in complex craters we document mineralogical heterogeneity in impact melt deposit on a scale of tens of kilometers on the moon in the 96 km diameter copernicus crater this heterogeneity is in the form of a large sinuous impact melt feature on the floor and northern wall that is spectrally distinct from melt in its immediate vicinity this melt feature spanning 30 km in length and 0 5 5 km in width has relatively short wavelength narrow ferrous absorption bands near 900 nm and 2000 nm indicating a more mg rich pyroxene composition as compared to impact melt deposit in the vicinity which is relatively rich in fe ca pyroxenes this distinction provides evidence for the preservation of compositional heterogeneity in impact melt in complex craters on the moon and documents an example of inefficient mixing of melt during the cratering process

mapping the feo and tio2 content of the lunar surface with multispectral imagery the derivation of quantitative elemental concentrations from multispectral imaging of the moon has long been a goal of lunar remote sensing concentration maps at the spatial resolutions available from the recent clementine mission would provide a revolutionary new tool for understanding the origin and evolution of the lunar crust lucey et al 1995 presented a method for extracting the concentration of fe from multispectral imaging of the moon this paper examines and quantifies important aspects ofthat technique left unexamined by lucey et al which had the potential to severely limit its utility these aspects include the effects of maturity grain size mineralogy shading due to topography and the presence of glass we also present a new algorithm for derivation of tio2 from multispectral imaging of both mare and highland units we find that both techniques are only weakly sensitive to maturity and that they have about 1 wt accuracy based on examination of the spectral properties and compositions of resolved lunar sampling stations presented by blewett et al 1997 we also discuss these findings in the context of two contrasting views of the effect of composition on lunar spectral properties presented by pieters and coworkers and hapke and coworkers we find the view of hapke and coworkers to be more consistent with our observations using a global mosaic of clementine multispectral data and these element derivation algorithms we find that the global modal abundance of feo is 4 5 wt 1 wt and the global modal abundance of tio2 is 0 45 wt 1 wt

global elemental maps of the moon the lunar prospector gamma ray spectrometer lunar prospector gamma ray spectrometer spectra along with counting rate maps of thorium potassium and iron delineate large compositional variations over the lunar surface thorium and potassium are highly concentrated in and around the nearside western maria and less so in the south pole aitken basin counting rate maps of iron gamma rays show a surface iron distribution that is in general agreement with other measurements from clementine and the lunar prospector neutron detectors

development of tongue shaped and multilobate rock glaciers in alpine environments interpretations from ground penetrating radar surveys abstract rock glaciers occur as lobate or tongue shaped landforms composed of mixtures of poorly sorted angular to blocky rock debris and ice these landforms serve as primary sinks for ice and water storage in mountainous areas and represent transitional forms in the debris transport system accounting for 60 of all mass transport in some alpine regions observations of active flowing alpine rock glaciers indicate a common association between the debris that originates from cirque headwalls and the depositional lobes that comprise them the delivery of this debris to the rock glacier is regulated primarily by the rate of headwall erosion and the point of origin of debris along the headwall these factors control the relative movement of individual depositional lobes as well as the overall rate of propagation of a rock glacier in recent geophysical studies a number of alpine rock glaciers on prins karls forland and nordenskioldland svalbard norway and the san juan mountains of southwest colorado usa have been imaged using ground penetrating radar gpr to determine if a relationship exists between the internal structure and surface morphology results indicate that the overall morphologic expression of alpine rock glaciers is related to lobate deposition during catastrophic episodes of rockfall that originated from associated cirque headwalls longitudinal gpr profiles from alpine rock glaciers examined in this study suggests that the difference in gross morphology between the lobate and tongue shaped rock glaciers can be attributed primarily but not exclusively to cirque geometry frequency and locations of debris discharge within the cirque and the trend and magnitude of valley gradient in relation to cirque orientation collectively these factors determine the manner in which high magnitude debris discharges which seem to be the primary mechanism of formation accumulate to form these rock glaciers

impact of a rock avalanche on a moraine dammed proglacial lake laguna safuna alta cordillera blanca peru hubbard bryn heald a reynolds j quincey d 2005 impact of a rock avalanche on a moraine dammed proglacial lake laguna safuna alta cordillera blanca peru earth surface processes and landforms 30 10 pp 1251 1264 rae2008

origin of olivine at copernicus the central peaks of copernicus are among the few lunar areas where near infrared telescopic reflectance spectra indicate extensive exposures of olivine other parts of copernicus crater and ejecta which were derived from highland units in the upper parts of the target site contain only low ca pyroxene as a mafic mineral the exposure of compositionally distinct layers including the presence of extensive olivine may result from penetration to an anomalously deep layer of the crust or to the lunar mantle we suggest that the procellarum basin and the younger superposed insularum basin have provided access to these normally deep seated crustal or mantle materials by thinning the upper crustal material early in lunar history the occurrences of olivine in portions of the compositionally heterogeneous aristarchus region in a related geologic setting may be due to the same sequence of early events

paraglacial landform assemblages in the hindukush and karakoram mountains abstract the paper focuses on the evolution of debris landforms in subtropical high mountain areas the karakoram and hindukush mountains are characterized by their high volume and variety of debris accumulations the valley flanks are coated by unconsolidated debris slopes up to 1000 m in height the valley floors are occupied by expansive debris flow cones and alluvial fans with escarpment heights of over 100 m the field investigations in over twenty valleys showed that the major part of those landforms is governed by the late and post glacial glaciation history a key role in this glacially controlled landscape system is played by the slope moraines which cover the valley flanks up to several hundred meters above the valley floor the secondary debris supply by resedimentation processes of moraine material and glacially induced rock failures exceed by far the primary debris production due to weathering processes landforms which have been formerly classified as periglacial talus cones rather can be considered as glacial or glacially controlled landforms the identified paraglacial landforms can serve as useful palaeoclimatic indicators for the ice age reconstruction

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

39ar 40ar dating of two lunar granites the age of copernicus previous investigations have suggested that kreep glass found in 12033 and other apollo 12 soils was ejected from the crater copernicus and deposited in a ray across this site soil fragment 12033 507 has been described as having a core of felsite granitic composition with a kreep glass shell 39ar 40ar dating of a sample of this granite material shows almost complete resetting 800 15 ma ago we interpret this age as giving the most precise determination to date for the formation time of copernicus cosmic ray exposure ages of the granite and associated kreep glass in soil 12033 about 250 ma are much less than the k ar age and suggest a complex postejection burial history the 39ar 40ar age of another granite fragment 14303 204 is determined to be in the range 3 80 3 85 ga this age is in agreement with 39ar 40ar ages determined for a few other lunar granites and is interpreted to represent resetting by a large basin forming impact probably imbrium

permafrost conditions in the mediterranean region since the last glaciation the relatively warm climate conditions prevailing today in the mediterranean region limit cold geomorphological processes only to the highest mountain environments however climate variability during the late pleistocene and holocene has led to significant spatio temporal variations of the glacial and periglacial domain in these mountains including permafrost conditions here we examine the distribution and evolution of permafrost in the mediterranean region considering five time periods last glaciation deglaciation holocene little ice age lia and present day the distribution of inactive permafrost derived features as well as sedimentary records indicates that the elevation limit of permafrost during the last glaciation was between 1000 m and even 2000 m lower than present permafrost was also widespread in non glaciated slopes above the snowline forming rock glaciers and block streams as well as meter sized stone circles in relatively flat summit areas as in most of the northern hemisphere the onset of deglaciation in the mediterranean region started around 19 20 ka the ice free terrain left by retreating glaciers was subject to paraglacial activity and intense periglacial processes under permafrost conditions many rock glaciers protalus lobes and block streams formed in these recently deglaciated environments though most of them became gradually inactive as temperatures kept rising especially those at lower altitudes following the younger dryas glacial advance the early holocene saw the last massive deglaciation in mediterranean mountains accompanied by a progressive shift of permafrost conditions to higher elevations it is unlikely that air temperatures recorded in mediterranean mountains during the holocene favoured the existence of widespread permafrost regimes with the only exception of the highest massifs exceeding 2500 3000 m lia colder climate promoted a minor glacial advance and the spatial expansion of permafrost with the development of new protalus lobes and rock glaciers in the highest massifs finally post lia warming has led to glacial retreat disappearance enhanced paraglacial activity shift of periglacial processes to higher elevations degradation of alpine permafrost along with geoecological changes

rock glaciers and the geomorphological evolution of deglacierizing mountains abstract rock glaciers are an important geomorphic element of glaciated mountain landscapes but our understanding of their distribution and ages controls on their development and their importance in regional mountain hydrology and mountain geomorphic evolution is incomplete in part this incomplete knowledge arises through problems associated with identifying rock glaciers on a morphological basis alone amplified by the multiple ways in which rock glaciers can form in different glacial periglacial and paraglacial settings this study focuses on rock glaciers as a paraglacial mountain landscape element and considers the relationships between rock glaciers and glacial periglacial and paraglacial processes new geomorphic and sedimentary data on different rock glaciers from the khumbu region of nepal are presented these data show that even within a single region rock glaciers may have varied origins and thus likely ages and different climatic and environmental controls we argue that rock glaciers in deglacierizing mountains may have a long residence time in the landscape unlike many other glacially influenced mountain landforms and can undergo significant morphodynamic changes as glaciated landscapes transition into paraglacial landscapes

mars surface diversity as revealed by the omega mars express observations the observatoire pour la mineralogie l eau les glaces et l activite omega investigation on board the european space agency mars express mission is mapping the surface composition of mars at a 0 3 to 5 kilometer resolution by means of visible near infrared hyperspectral reflectance imagery the data acquired during the first 9 months of the mission already reveal a diverse and complex surface mineralogy offering key insights into the evolution of mars omega has identified and mapped mafic iron bearing silicates of both the northern and southern crust localized concentrations of hydrated phyllosilicates and sulfates but no carbonates and ices and frosts with a water ice composition of the north polar perennial cap as for the south cap covered by a thin carbon dioxide ice veneer

assessing glacier features supporting supraglacial trees a case study of the miage debris covered glacier italian alps the number of debris covered glaciers featuring supraglacial trees is increasing worldwide as a response of high mountain environments to climate warming generally their distribution on the glacier surface is not homogeneous thus suggesting that some glacier parameters influence germination and growth of trees in this study we focused our attention on the widest italian debris covered glacier the miage glacier mont blanc massif we analyzed the ablation area in the range from 1730 to 2400 m a s l where continuous debris coverage is present and trees are found using data obtained by remote sensing investigations and field surveys we defined a record of glacier parameters to be analyzed with respect to the presence and abundance of trees we found that supraglacial trees are present at the miage glacier 1 whenever exceeding a debris thickness threshold 19 cm 2 with a gentle slope 10 3 with a low glacier surface velocity 7 0 m yr and 4 where the vertical changes due to glacier

bent glacier tongues a new look at lliboutry s model of the evolution of the crooked jatunraju glacier paron valley cordillera blanca peru abstract the article tackles the issue of which factors may influence the flow direction and morphological shape of glacier tongues terminating at tributary junctions to the main valley in high mountain landscapes a very particular morphological form of a glacier tongue shows the jatunraju glacier in the cordillera blanca peru it terminates in the superior paron valley with a prominent crooked form embedded in a 250 m high moraine pedestal lliboutry 1977 has explained the deviation of the jatunraju glacier tongue as a result of a proglacial lake outburst alternative hypothetical models on a general scale have been developed for the causes determining the morphological characteristics of glacier tongues these are based on empirical field evidence from the paron valley and from glaciers located in other high mountain areas in particular in the himalaya region where glacier tongues in confluence settings are abundant the comparative investigations demonstrate that the pronounced crooked form of the jatunraju glacier may not be the result of a single extreme event but may have been produced as well by gradual processes in a general context the study shows that crooked glacier tongues are common landforms in other mountain regions and mainly intrinsic to debris covered glaciers the morphological evolution of glacier tongues may involve a polygenetic process pattern over a longer geological time period apart from the steepness of the valley gradient of the main valley the former confluence from the source glacier with the main glacier during times of a more extensive glaciation is regarded as one of the dominating factors controlling the later evolution of glacier tongues in general inherited confluence model

a sharper view of impact craters from clementine data the ultraviolet visible camera on the clementine spacecraft obtained high spatial resolution images of the moon in five spectral channels impact craters mapped with these multispectral images show a scale of lithologic diversity that varies with crater size and target stratigraphy prominent lithologic variations feldspathic versus basaltic occur within the south wall of copernicus 93 kilometers in diameter on the scale of 1 to 2 kilometers lithologic diversity at tycho 85 kilometers in diameter is less apparent at this scale although the impact melt of these two large craters is remarkably similar in this spectral range the lunar surface within and around the smaller crater giordano bruno 22 kilometers in diameter is largely dominated by the mixing of freshly excavated material with surrounding older soils derived from a generally similar feldspathic lithology

near infrared spectral reflectance of mineral mixtures systematic combinations of pyroxenes olivine and iron oxides near infrared spectral reflectance data are presented for systematic variations in weight percent of two component mixtures of ferromagnesian and iron oxide minerals mixtures were chosen for application to the study of the dark materials on mars but the results are equally applicable to mafic and ultramafic assemblages elsewhere in the solar system olivine spectral features are greatly reduced in contrast by admixture of other phases but remain distinctive even for low olivine contents clinopyroxene and orthopyroxene mixtures show resolved pyroxene absorptions near 2 m the addition of limonite greatly modifies pyroxene and olivine reflectance but does not fully eliminate distinctive spectral characteristics using only spectral data in the 1 m region it is difficult to differentiate orthopyroxene and limonite goethite in a mixture additional spectral coverage or other evidence may be required for a unique interpretation all composite mineral absorptions observed in this study are either weaker than or intermediate in strength to the end member absorptions and have bandwidths greater than or equal to those for the end members in general spectral properties in an intimate mixture combine in a complex nonadditive manner with features demonstrating a regular but usually nonlinear variation as a function of end member phase proportions

copernicus a regional probe of the lunar interior earth based telescopic spectral imaging techniques were used to document the spatial distribution of crater materials within the large lunar crater copernicus at the subkilometer scale on the basis of spectral ultraviolet visible near infrared characteristics the proposed spectral mixing analysis leads to a first order mapping of the impact melt material within the crater olivine was detected not only within the three central peaks but also along a significant portion of the crater rim consideration of an olivine bearing end member in the mixing model emphasizes the overall morphological pattern of the rim and wall terraces in the associated fraction image the identification of widely exposed olivine units supports the idea that the lower crust and possibly the lunar mantle itself are regionally at shallow depth

engineering geomorphology of rock glaciers a partnership between geomorphology and engineering is facilitating human development in this harsh environment rock glaciers provide locations for urban water sources construction borrow sources drill sites shaft and tunnel portals ski tower supports and dam abutments rock glaciers as dynamic landforms necessitate proper identification in the field placing structures on in or adjacent to rock glaciers requires an appreciation and understanding of their temporal stability internal and surface characteristics provide important clues to the development and deformation of rock glaciers rock glaciers play a significant role in the alpine debris transport system active movement and mass wasting are perhaps the most obvious geologic hazards affecting engineered works the structure of the rock glacier is conducive to the production of a steady continuous supply of meltwater during summer months thus rock glaciers serve as alpine aquifers consideration of rock glaciers as potential aquifer sources requires caution because of the long term impact of climate change on the temporal nature of the landform from the rock glaciers that we have monitored for water quality characteristics it appears that they provide quality potable water this paper provides a foundation for appreciation and understanding of rock glaciers from an engineering geomorphologic point of view the approach taken in this paper provides practical important information to aid the engineer and engineering geologist in prudent evaluations of rock glaciers as potential sites for human development and uses the bottom line of our paper is rock glaciers must be avoided for essentially all structures

an isotopic and geochemical study of snowmelt runoff in a small arctic watershed old water contributions to snowmelt runoff in a stream can be defined as water which was stored in the catchment prior to the start of the runoff event in question we used mass balance techniques for natural oxygen 18 and several chemical parameters electrical conductivity ca and mg to estimate the magnitude and timing of old water contributions to snowmelt runoff in the apex river watershed during the 1983 field season the apex river catchment is located in the southern part of baffin island northwest territories canada the watershed has an area of 60 km2 it is in the zone of continuous permafrost and the geology is dominantly precambrian gneiss with sporadic thin glacial overburden the isotopic data indicate that for the snowmelt season of 1983 third highest peak discharge of 11 years of record approximately 50 per cent of the peak stream discharge consisted of old water our data also suggest that about 60 per cent of the entire 1983 hydrograph was old water the chemical parameters give old water contributions which are at least 10 per cent less than the isotopically derived estimate but they are consistent with the isotopic estimate during peak flow

terrestrial impact structures impact structures are the dominant landform on planets that have retained portions of their earliest crust the present surface of the earth however has comparatively few recognized impact structures this is due to its relative youthfulness and the dynamic nature of the terrestrial geosphere both of which serve to obscure and remove the impact record although not generally viewed as an important terrestrial as opposed to planetary geologic process the role of impact in earth evolution is now receiving mounting consideration for example large scale impact events may have been responsible for such phenomena as the formation of the earth s moon and certain mass extinctions in the biologic record the importance of the terrestrial impact record is greater than the relatively small number of known structures would indicate impact is a highly transient high energy event it is inherently difficult to study through experimentation because of the problem of scale in addition sophisticated finite element code calculations of impact cratering are gen erally limited to relatively early time phenomena as a result of high com putational costs terrestrial impact structures provide the only ground truth against which computational and experimental results can be com pared these structures provide information on aspects of the third dimen sion the preand postimpact distribution of target lithologies and the nature of the lithologic and mineralogic changes produced by the passage of a shock wave they also provide data for cratering rate estimates and in some cases on the nature of the impacting body in this review emphasis is placed on the nature of terrestrial impact structures the criteria for their identification and their contribution to

waterways ice permeability at depth and water pressures at glacier d argentiere french alps pour eclaircir les changements survenus a la prise d eau sous glaciaire du glacier d argentiere une etude approfondie a ete realisee en 1979 80 avec 31 forages et un carottage jusqu au fond 240m juste en amont de la prise dans une zone surcreusee on observe que la glace en dessous d environ 100 m de profondeur est legerement permeable on a mesure la pression interstitielle de l eau dans la glace profonde le gradient piezometrique entre les trous de forage et le dephasage entre les fluctuations du niveau d eau qui augmente lorsqu on s eloigne de la rive droite il n y a pas de torrent sous glaciaire au fond du surcreusement sauf a son extremite amont la plupart de l eau de fonte doit s ecouler entre glace et rocher le long de la rive droite sa surface libre s elevant d environ 150 m au moment de l engorgement de juin on n a pas trouve de correlation nette entre la pression de l eau interstitielle profonde et la temperature de l air ou le debit a la prise sous glaciaire en aval

the materials of the lunar procellarum kreep terrane a synthesis of data from geomorphological mapping remote sensing and sample analyses major features of the moon s procellarum kreep terrane include subdued relief and extensive resurfacing with mare basalt consistent with high concentrations of th and other heat producing elements at depth we relate the chemistry of sampled materials to the geomorphology th surface concentrations determined by the lunar prospector 2 pixels and feo and tio2 concentrations derived from clementine ultraviolet visible spectral data on the basis of geologic maps each pixel was classified as mare terra or mixed near the periphery of the terrane terra pixel compositions are relatively feldspathic in the interior they mainly represent imbrium basin rim or ejecta deposits and are mainly incompatible trace element rich norites and presumably represent materials from a thick section tens of kilometers of the pre imbrium crust of the terrane excavated by the imbrium event although imbrium ejecta are the principal source of surface terra materials the imbrium event did not create the th rich procellarum kreep terrane broad continuous expanses of mare pixels are observed with little interruption from protruding terra or terra penetrating craters the mare basalt dominated regoliths of these areas have a wide range of tio2 concentrations 18 leading to the conclusion that the high th concentrations are in the mare basalts and are not present in the regoliths as terra derived materials volcanic glasses and impact glasses of mare basalt composition collected from the procellarum kreep terrane support this conclusion

constraints on the timing of debris covered and rock glaciers an exploratory case study in the holar area northern iceland abstract eighteen samples for 36cl cosmic ray exposure cre dating were taken from glacially polished bedrocks moraine boulders fossil active rock glaciers and debris covered glaciers in fremri grjotardalur and holadalur cirques in the vi inesdalur hofsdalur and he insdalur valleys close to holar village in the trollaskagi peninsula northern iceland boulder sampling was preceded by a study of the boulder stability with the twofold aim of ensuring that the surfaces to be sampled were stable enough for the reliable application of cre dating and to better understand the relation between the glacier dynamics and exposition history the results show that the glaciers which occupy the valleys in trollaskagi began their retreat around 16 ka later the glaciers advanced again around 11 ka within the cirques and small moraines were formed thereafter these small glaciers retreated and evolved into rock glaciers as debris from paraglacial processes accumulated on the glacier surface the fronts of these rock glaciers stabilized definitively shortly after their formation and became eventually fossil after the melting of their internal ice new rock glaciers and debris covered glaciers formed afterwards which still have internal ice at present although their current dynamics are mostly related to subsidence the stabilization of these rock glaciers and debris covered glaciers is dated to the period between 7 and 3 ka although they may have been reactivated during cold neoglacial periods this research demonstrates the potential interest in applying cre dating methods to debris covered glaciers and rock glaciers to determine their origin evolution and phase of cessation of internal movement until they finally lost their internal ice and became fossil

rapid ice margin fluctuations during the younger dryas in the tropical andes abstract radiocarbon dated lacustrine sequences in peru show that the chronology of glaciation during the late glacial in the tropical andes was significantly out of phase with the record of climate change in the north atlantic region fluvial incision of glacial lake deposits in the cordillera blanca central peru has exposed a glacial outwash gravel radiocarbon dates from peat stratigraphically bounding the gravel imply that a glacier advance culminated between 11 280 and 10 990 14c yr b p rapid ice recession followed similarly in southern peru ice readvanced between 11 500 and 10 900 14c yr b p as shown by a basal radiocarbon date of 10 870 14c yr b p from a lake within 1 km of the quelccaya ice cap by 10 900 14c yr b p the ice front had retreated to nearly within its modern limits thus glaciers in central and southern peru advanced and retreated in near lockstep with one another the younger dryas in the peruvian andes was apparently marked by retreating ice fronts in spite of the cool conditions that are inferred from the 18o record of sajama ice this retreat was apparently driven by reduced precipitation which is consistent with interpretations of other paleoclimatic indicators from the region and which may have been a nonlinear response to steadily decreasing summer insolation

field investigations of the nature of water table response to precipitation in shallow water table environments abstract several water table response tests performed in undulating topography at a field site near chalk river ontario are analysed the objective of the experiments was to gather detailed field information on the nature of the water table rise in response to precipitation in a shallow water table environment the tests were performed by applying simulated rainfall to a study site instrumented in detail with porous membrane tensiometers changes in hydraulic head were measured using a pressure transducer and a hydraulic switch a disproportionate rise in the water table was observed in areas where the zone of tension saturation capillary fringe extended to ground surface for example for rainfall of 5 mm over a duration of 5 3 min the water table in the lowest lying areas rose about 13 cm while the rise in the area of higher ground was only 5 cm furthermore as a result of the difference in response between the low lying and higher ground complex and transient hydraulic gradients were established directed away from the low lying area the magnitude of the response in the low lying area can only be explained by the presence of the capillary fringe

rock glacier nomenclature a re assessment several contentious issues have arisen from rock glacier nomenclature for example whether the term rock glacier implies genesis from glacial ice or genesis from permafrost the situation is compounded since rock glacier classification may be based on several different parameters some of which are measured and quantified others inferred these include gross morphology dynamics processes of formation location internal characteristics thermal regime and age uncertainties in specifying the genesis in the light of the potential complexity means that definitions should be related to recognisable topographic forms which allow mapping of such features the distinction is made between rock glaciers sensu stricto which follows the original descriptions and typology of the early years of the 20th century and protalus lobes the forms can usually be differentiated in terms of length breadth ratios as well as by their relative locations some of the most common issues of contention within rock glacier research can be solved by this approach

petrogenesis of lunar troctolites models of petrogenesis for lunar troctolites are severely constrained by the high mg 88 values of the most primitive members of the mg rich suite melts derived by partial melting of olivine cumulates to the lunar magma ocean have high mg but are strongly undersaturated with respect to plagioclase assimilation of lunar crust cannot bring these melts to the plagioclase liquidus without unduly reducing the mg values of olivine partial melts derived by melting a iherzolite primitive interior have higher normative plagioclase contents but require sources with mg 90 more terrestrial like mg 88 values are permitted if rising thermal plumes are capable of entraining the most mg rich cumulates of the magma ocean the mg values of lunar troctolites may therefore reflect a hybrid source composed of primitive mantle and mg rich cumulates of the magma ocean higher mg values may also arise from the reduction of small amounts of feo to fe alternatively the parent magmas to lunar troctolites may be impact melts of the anorthositic crust and the mg rich dunite cumulates of the magma ocean the latter were brought to the upper mantle during the overturn of the unstable cumulate pile of the magma ocean

mapping global lunar abundance of plagioclase clinopyroxene and olivine with interference imaging spectrometer hyperspectral data considering space weathering effect abstract mineral mapping of the lunar surface is critical to understanding the moon s geological diversity and history yet the global lunar abundance of minerals has not been mapped using hyperspectral data the interference imaging spectrometer iim of chang e 1 mission obtained hyperspectral data of the global lunar surface within the wavelength of 480 960 nm in which major minerals can be discriminated by faint differences in 32 contiguous hyperspectral bands the effect of space weathering produces multiple endmembers of lunar minerals by obscuring the pure spectra of minerals in different levels in this study the distributions of plagioclase clinopyroxene and olivine on the global lunar surface were mapped with iim hyperspectral data based on the modified multiple endmember spectral mixture analysis mesma method considering the space weathering effect the distribution of lunar space weathering levels was retrieved as a byproduct of mineral mapping the mineral mapping results were compared with recent mapping results although the wavelength of iim is limited it shows that our results are basically consistent with the recent research at both global and local scales the distribution of space weathering levels is also consistent with the map of optical maturity parameter omat in most parts of the global lunar surface especially in the highlands this study demonstrates that the modified mesma method is an effective approach to quantitative mapping of the lunar minerals and space weathering levels using hyperspectral data in the future more minerals can be mapped with higher accuracy if hyperspectral data with a wider spectral range are used based on the method proposed in this study

the problem of hidden ice in glacier mapping lee can become hidden i e buried by the superimposition of rock debris on a glacier or where rock debris may incorporate interstitial ice because it is obscured problems result from a lack of understanding of the extent and continued activity of such ice landforms may be associated with this phenomenon and can be used as indirect evidence of its existence a rock glacier can contain glacially derived buried ice as well as interstitial ice we show with examples how such rock glaciers can be identified and provide information on the extent and possible volume of hidden ice in marginally glacierized and permafrost areas in most cases recognition of topography is sufficient although time separated aerial photographs may be necessary to locate the extent of ice these are generally preferable to and more cost effective than most detailed on site determinations of ice extent it is possible to incorporate and extend knowledge of hidden ice in glacier mapping and inventory projects

hillslope and wetland hydrodynamics in a tussock grassland south island new zealand previous research on two experimental catchments at the glendhu forest otago showed that runoff dynamics from this landscape differ substantially from other areas in new zealand in particular the recession curves from these catchments have two distinct phases a rapid decline for a period of several hours followed by a slow decline that may last many days to weeks in the current study soil water matric potential measurements indicated that perched saturated zones develop very rapidly in the surface 0 30 cm soil horizons deep 50 250 cm loess horizons remain moist throughout the year and may be near or at saturation at the bedrock contact and respond only slowly to rain events soils in the middle horizons are often drier than the surface soil above or the deep soils below throughflow measurements showed that storm runoff occurs primarily as interflow through a retentive but pervious mat of mosses litter and roots at the soil surface despite the presence of abundant earthworm burrows less water is transmitted through the soil horizon just below this surface mat only a small fraction of stormflow was transmitted through the deep mineral horizons however baseflow could be sustained for long periods up to 4 weeks from unsaturated flow of soil moisture stored in the deep loess horizons water storage in bog peats and associated riparian soils which are numerous in this area is insufficient to sustain baseflow for more than a few days the results from this study are consistent with previous hydrometric soils and isotopic observations and suggest that any land use practices that disrupt the surface soil horizons are likely to change the runoff characteristics of this area

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

space weathering on the moon patina on apollo 17 samples 75075 and 76015 we studied patinas on lunar rocks 75075 and 76015 from the apollo collection using a multi disciplinary approach including scanning electron microscopy sem energy dispersive x ray spectrometry eds transmission electron microscopy tem wavelength dispersive x ray wds mapping mossbauer spectroscopy spectral reflectance and microspectrophotometry based on sem petrography we have defined three textural types of patina glazed fragmental and classic cratered the presence of classic patina is diagnostic of lunar samples that have been exposed directly to the space weathering environment it is characterized by the presence of microcraters and glass pancakes and is the patina type studied by earlier workers classic patina is found on 76015 but not on 75075 glazed patina is found on both 76015 and 75075 whereas fragmental patina is found only on 75075 the glazed and fragmental patinas on 75075 were probably formed as a result of relatively large nearby impacts and although these two types of patina are not strictly the result of direct exposure to the space weathering environment they are important because they affect the optical properties of the rocks field emission gun sem fe sem of classic patina on 76015 shows evidence of possible solar wind sputtering erosion transmission electron microscope studies of 76015 reveal the presence of impact generated deposits and solar flare particle tracks which like microcraters and pancakes are diagnostic of direct exposure to space weathering processes the outermost surface of the 76015 patina consists of an amorphous rim very much like the rims found on individual lunar soil grains this amorphous patina rim probably formed by similar processes of impact generated vapor condensation and possible sputter deposition wavelength dispersive x ray element maps of polished thin sections of 75075 and 76015 indicate that patina compositions are poor indicators of the compositions and mineralogies of the rocks underlying them on average the reflectance spectra of patinas on both samples are slightly darker than those of their unweathered equivalents microreflectance measurements show that a thick patina can dramatically alter the optical properties of the rock on which it forms the backscatter mossbauer bams spectrum of a patina covered surface of 76015 is very similar to that of an unweathered surface indicating that the mossbauer signal is generated from beneath the patina because bams sees through surface space weathering effects to the underlying rock this technique has great potential for use in robotic missions to other planetary bodies

glacial landform assemblages and pedestal moraines in the cordillera blanca peru abstract the article provides a contribution to the glacial geomorphology of tropical high altitude mountains it focuses on the diversity of glacial landforms in the cordillera blanca peru the landforms are classified as individual landform types as well as in their hypsometric sequence their spatial arrangement is depicted in vertical series and summarised in a glacial morphological altitudinal belt model the glacial landforms are analysed in a genetic succession from the moraine delimited glacier forefields to the excessive pedestal moraines and taking account of the topographical conditions in the verticality the pleistocene glacial relief formation is considered as one of the dominating factors in the development of the moraine types the sediments are on the one hand in situ deposition forms and on the other depositions dislocated by mass movements and represent paraglacial landforms using the example of the paron valley in the artesonraju huandoy massif and neighbouring valleys the article provides a typology of the range of glacial and paraglacial landforms based on a holistic glacial landsystem approach with special reference to pedestal moraines

near infrared spectroscopy of probable impact melt from three large lunar highland craters abstract the composition of small areas within three large lunar highland craters are compared using near infrared earth based telescopic data spectra from many areas in the walls and central peaks of the craters indicate the presence of crystalline components which include olivine two types of pyroxene and sometimes fe bearing feldspar spectra from other regions suspected of being impact melt deposits located on the floors and walls of the three craters have remarkably similar yet anomalous features these features are interpreted to indicate the presence of pyroxene fe bearing glass and fe bearing feldspar pyroxene and feldspar are believed to occur primarily in the form of lithic clasts and rapidly recrystallized impact melt the fe bearing glass is interpreted as impact melt glass

a reinterpretation of scottish hummocky moraine and its significance for the deglaciation of the scottish highlands during the younger dryas or loch lomond stadial the aim of this paper is to demonstrate that much of the hummocky moraine present within the northern part of the lochlomond readvance ice cap formerly situated in the north west scottish highlands may be interpreted as suites of ice front moraines deposited during active decay these landforms can be used to reconstruct ice cap decay whichleads to important insights into the shrinking form of the ice cap and associated environmental conditions evidence has been collected from 10803 airphotographs and from detailed field survey it is presented at three spatial scales

late pleistocene piedmont glaciations in the eastern mediterranean insights from cosmogenic 36cl dating of hummocky moraines in southern turkey abstract we report the presence of late pleistocene piedmont glaciers represented by the largest hummocky moraine field observed in the eastern mediterranean the piedmont glaciers originated from the geyikdag ice cap 40 km 2 situated between 2350 and 2650 m above sea level a s l central tauride mountains of turkey and deeply carved the north facing hillslopes before reaching the namaras valley 2000 2050 m a s l the hummocky moraines resulted from in situ deposition of stagnant glacier ice where debris cover was heterogeneously distributed on the glacier surface thirty four boulders from hummocky disintegration lateral and terminal moraines from the namaras valley and the tributary susam valley 2100 2200 m a s l were dated by cosmogenic 36 cl surface exposure dating the moraine ages indicate three phases of deglaciation during the late pleistocene the oldest deglaciation occurred in the namaras valley at 18 0 1 1 ka ka thousand years ago towards the end of the last glacial maximum lgm and is recorded entirely by hummocky moraines we speculate that hummocky moraine forming processes with cycles of relief inversion gave rise to boulder apparent ages up to a few thousand years younger in our study area therefore 18 0 1 1 ka should be regarded as a minimum age with a probable true age much closer to the local lgm values 20 ka as observed in the surrounding mountains paleo piedmont glaciers also deposited several lateral moraines that are 50 m higher than the hummocky moraines although the lateral moraines probably represent the build up and the hummocky moraines the final phase of the same local lgm pulse both lateral moraines started to retreat from the late glacial 14 0 2 7 ka and gradually disappeared by mid holocene 5 2 1 0 ka encompassing the younger dryas yd stadial in the susam valley the late glacial is represented by a terminal moraine 13 4 1 5 ka the glacier retreat was very fast as indicated by an almost instantaneous disappearance of 5 km long susam valley glacier represented by disintegration and hummocky moraines 14 0 1 3 ka alternatively in case the oldest boulder age is taken into account the susam valley glacier can be also attributed to the late lgm 17 ka to late glacial 14 ka transition near the exit of the susam valley a right lateral moraine was deposited 11 6 1 3 ka ago confirming the presence of the yd in geyikdag comparable glacial chronologies were obtained from other turkish and mediterranean mountains

an in depth look at the lunar crater copernicus exposed mineralogy by high resolution near infrared spectroscopy abstract newly acquired sequentially spaced high resolution near infrared spectra across the central section of crater copernicus interior have been analyzed using a range of complementary techniques and indexes we have developed a new interpretative method based on a multiple stage normalization process that appears to both confirm and expand on previous mineralogical estimations and mapping in broad terms the interpreted distribution of the principle mafic species suggests an overall composition of surface materials dominated by calcium poor pyroxenes and minor olivine but with notable exceptions the southern rim displays strong ca rich pyroxene absorption features and five other locations the uppermost northern crater wall opposite rim sections facing the crater floor and the central peak pk1 and at the foot of pk3 show instead strong olivine signatures we also propose impact glass an alternative interpretation to the source of the weak but widespread olivine like spectral signature found in low reflectance samples since it probably represents a major regolith constituent and component in large craters such as copernicus the high quality and performance of the sir 2 data allows for the detection of diagnostic key mineral species even when investigating spectral samples with very subdued absorption features confirming the intrinsic high quality value of the returned data

a comparative study of iron abundance estimation methods application to the western nearside of the moon abstract the feo weight percentage wt abundance of the moon s western nearside 55 s 55 n and 5 e 40 w is estimated using data from the infrared spectrometer 2 sir 2 and the moon mineralogy mapper m3 in this study we modified an feo abundance estimation algorithm bhatt m mall u bugiolacchi r mckenna lawlor s banaszkiewicz m nathues a ullaland k 2012 icarus 220 51 64 which relies exclusively on the 2 m absorption band parameters the modified feo abundance estimation algorithm and the regression based elemental abundance estimation algorithm wohler c grumpe a berezhnoy a bhatt m u mall u 2014 icarus 235 86 122 which is based on the 1 m and 2 m absorption band parameters is applied to the m3 data we have compared results obtained from these two modified algorithms with a previously published clementine s feo wt map lucey p g blewett d t jolliff b l 2000 j geophys res 105 20297 20306 the effects of topography and space weathering on feo wt estimates have been successfully minimized using the modified algorithm based on the 2 m absorption band parameters thus this algorithm can be successfully applied at middle to high latitudes furthermore a correction for tio2 is applied to the feo abundance estimation algorithm based on the 2 m absorption band parameters using the m3 data our comparative study shows a good correspondence between the three algorithms discussed there are two locations the crater tycho and the region around rima bode which show major discrepancies our modified algorithm based on the 2 m absorption parameters predicts 3 4 wt less feo for the ray system of tycho than for the surrounding region the average iron abundance for the lunar highlands is about 6 wt and for the mare regions is about 16 wt using the regression based elemental abundance estimation algorithm and the algorithm based on the 2 m absorption parameters this result is consistent with the previous analysis using lunar prospector gamma ray spectrometer data sets the feo wt is in the range 20 24 wt for the high ti basalts using both the modified iron abundance estimation and the regression based elemental abundance estimation algorithms

composition of the lunar highland crust from near infrared spectroscopy near infrared reflectance spectra of the lunar highlands are synthesized to obtain global information about the composition of the lunar near side crust immature exposed surfaces from small fresh craters mountains and massifs and large craters with central peaks are included in a survey of rock types across the lunar near side compositions recognized in these data include anorthosite noritic gabbric and troctolitic mineral assemblages three quarters of the areas studied that represent samples from the upper 1 2 km of lunar crust exhibit noritic compositions with different amounts of pyroxene and or brecciation alteration norites are ubiquitous across the near side and show no spatial clustering associated with any of the major basins in contrast to this noritic megaregolith of the upper crust material representing stratigraphically deeper zones 5 15 km of the lunar crust is dominated by gabbros anorthosites and troctolites with less than a quarter of the areas studied exhibiting a noritic composition the origin of the noritic megaregolith and its relation to deeper crustal material is thus somewhat of an enigma the current limited statistics for areas identified as anorthosites and troctolites are insufficient to derive global spatial distributions gabbroic areas however are notably concentrated in the western hemisphere although incomplete for a global assessment of crustal materials these data demonstrate that the lunar near side crust is clearly mineralogically heterogeneous both laterally and vertically and not well mixed below 1 2 km

dynamics of an active rock glacier otztal alps austria the rock glacier innere olgrube located in a small side valley of the kauner valley otztal alps austria consists of two separate tongue shaped rock glaciers lying next to each other investigations indicate that both rock glaciers contain a core of massive ice during winter the temperature at the base of the snow cover bts is significantly lower at the active rock glacier than on permafrost free ground adjacent to the rock glacier discharge is characterized by strong seasonal and diurnal variations and is strongly controlled by the local weather conditions water temperature of the rock glacier springs remains constantly low mostly below 1 c during the whole melt season the morphology of the rock glaciers and the presence of meltwater lakes in their rooting zones as well as the high surface flow velocities of 1 m yr point to a glacial origin the northern rock glacier which is bounded by lateral moraines evolved from the debris covered tongue of a small glacier of the little ice age with its last highstand around a d 1850 due to the global warming in the following decades the upper parts of the steep and debris free ice glacier melted whereas the debris covered glacier tongue transformed into an active rock glacier due to this evolution and due to the downslope movement the northern rock glacier although still active at present is cut off from its ice and debris supply the southern rock glacier has developed approximately during the same period from a debris covered cirque glacier at the foot of the wannetspitze massif

a chemical model for generating the sources of mare basalts combined equilibrium and fractional crystallization of the lunar magmasphere abstract it is generally considered that mare basalts were generated by the melting of a cumulate mantle formed in an early moon wide magma ocean or magmasphere however the nature and chemistry of this cumulate mantle and the logistics of its origin have remained elusive extensive studies of terrestrial layered mafic intrusions over the past sixty years have emphasized the imperfection of fractional crystallization and attendant crystal crystal and crystal liquid separation in a convecting magma chamber crystal liquid and crystal crystal separations were similarly inefficient during evolution of the lunar magma ocean lmo allowing for the trapping of interstitial liquid and entrainment of a small proportion of less dense plagioclase into the denser mafic cumulate mush indeed petrography of lunar highlands samples demonstrates this for anorthosites with 1 10 olivine the residual liquid after 80 90 crystallization was very evolved in fact kreepy and even in small proportions 1 5 would have a noticeable effect on the trace element chemistry of melts generated from these cumulates this trapped residual liquid would elevate total ree abundances in the cumulate pile while synchronously deepening the already negative eu anomaly essentially this trapped liquid will make the cumulate more fertile for melting to generate both kreep basalt and mare basalt magmas plagioclase entrained in the mafic cumulate pile adds an essential al component to the high ti basalt source and will moderate the requisite negative eu anomaly in the cumulate early in the evolution of the lunar mantle when the lmo still was largely liquid it is likely that vigorous convection was an important factor in crystallization such convection would allow crystals to remain suspended and in equilibrium with the lmo liquid for relatively long periods of time this extended period of equilibrium crystallization would then have been followed by fractional crystallization once plagioclase became a liquidus phase and began to float to form the lunar highlands crust previous authors have proposed a three component model for the evolution of high ti mare basalt source regions this model includes kreep early olivine rich high mg cumulates and late ilmeniterich low mg cumulates in various proportions however we propose a model for high ti basalt parent magmas which is in accord with studies of terrestrial layered intrusions this model for the high ti source includes trapped instantaneous residual liquid tirl 1 3 and entrainment of a small 2 5 proportion of plagioclase into the late stage cumulate pile in order to account for both the observed al compositions and trace element characteristics of high ti mare basalts melting of this relatively shallow ilmenite and clinopyroxene bearing late stage cumulate can generate high ti mare basalt magmas furthermore we are in agreement with other workers that only through a process of nonmodal melting will the high ti values for the parent magmas be realized large scale convective overturn of the cumulate pile and mixing of kreep with early and late stage cumulates is not required however localized overturn of the upper tenth of the cumulate pile is likely and in fact required to achieve an appropriate major element balance for the high ti mare basalt source region

debris covered glaciers in the sierra nevada california and their implications for snowline reconstructions abstract ice walled melt ponds on the surfaces of active valley floor rock glaciers and matthes little ice age moraines in the southern sierra nevada indicate that most of these landforms consist of glacier ice under thin ca 1 10 m but continuous covers of rock fall generated debris these debris blankets effectively insulate the underlying ice and greatly reduce rates of ablation relative to that of uncovered ice such insulation explains the observations that ice cored rock glaciers in the sierra actually debris covered glaciers are apparently less sensitive to climatic warming and commonly advance to lower altitudes than do adjacent bare ice glaciers accumulation area ratios and toe to headwall altitude ratios used to estimate equilibrium line altitudes elas of former glaciers may therefore yield incorrect results for cirque glaciers subject to abundant rockfall inadvertent lumping of deposits from former debris covered and bare ice glaciers partially explains an apparently anomalous regional ela gradient reported for the pre matthes recess peak neoglacial advance distinguishing such deposits may be important to studies that rely on paleo ela estimates moreover matthes and recess peak ela gradients along the crest evidently depend strongly on local orographic effects rather than latitudinal climatic trends indicating that simple linear projections and regional climatic interpretations of ela gradients of small glaciers may be unreliable

deconvolution of lunar olivine reflectance spectra implications for remote compositional assessment lunar olivines typically contain inclusions of cr spinel chromite that influence their measured optical properties these altered optical properties complicate modeled predictions of olivine composition from reflectance spectra approaches developed for inclusion free terrestrial olivine spectra must be modified to be applied to chromite bearing lunar olivine spectra we present a revised approach for predicting the compositions of chromite bearing lunar olivines using the modified gaussian model mgm the results of this revised approach for chromite bearing lunar olivines are consistent with previous results for terrestrial olivine reflectance spectra and successfully predict the olivine s composition these results are an important step in compositional assessment of remotely sensed olivine spectra and are essential to ongoing investigations of that topic our results are based on a limited set of available lunar olivine separates and would be strengthened by the inclusion of additional compositions

copernicus crater central peak lunar mountain of unique composition olivine is identified as the major mafic mineral in a central peak of copernicus crater information on the mineral assemblages of such unsampled lunar surface material is provided by near infrared reflectance spectra 0 7 to 2 5 micrometers obtained with earth based telescopes the composition of the deep seated material comprising the copernicus central peak is unique among measured areas other lunar terra areas and the wall of copernicus exhibit spectral characteristics of mineral assemblages comparable to the feldspathic breccias returned by the apollo missions with low calcium orthopyroxene being the major mafic mineral