Glacial Geology

Machine learning (ML) methods of satellite image analysis were applied in this study for geological-environmental analysis of glacier extent in Tibetan Plateau, China. The purpose of this work is to map the changes in glacier extent as a hydrological resource and its effects on land cover types using remote sensing data. A quantitative cartographic method of image analysis has been developed using ML algorithms and GRASS GIS scripts. Fluctuations of glacier extent are a key trigger for landscape dynamics in Tibetan Plateau. However, the links between spatio-temporal changes in snow and glacier, and associated land cover changes remain elusive. Six Landsat 8-9 multispectral satellite images covering Lhasa were evaluated. The images show fluctuation in glacier coverage from 2013 to 2023 with a 2-year gap between the observations, characterized by strong heterogeneities caused by climate changes. Glacier dynamics was evaluated for northern range of Nyenchen Tanglha Mountains and Lhasa Terrane, Tibetan Plateau, China. The results present an exploratory analysis of six images (on 2013, 2015, 2017, 2019, 2021 and 2023) for glaciological modelling using ML.

A strong basis of observational data is crucial for improving the understanding of the physical processes driving these changes, and for improving models used to predict the state of the cryosphere in the future. mm /yr rise in sea level (unpublished data from IES and IMO; Björnsson et al., submitted). The DEMs are being used in several glaciological and geomorphological research projects of subglacial eruptions, jökulhlaups and hazard assessments for settlements near the glaciers and they will be useful in research of glacier dynamics such as studies of surges, calving, subglacial water flow and ice flow over bedrock topography. The very high resolution and good relative accuracy also make LiDAR maps useful for mapping crevasses and the creation of various special purpose maps of the glaciers, including maps to improve the safety of travel and search and rescue operations on the glaciers.

About 60% of glaciers in Iceland are underlain by an active volcanic zone (Fig. 1). Ice is continuously melted at a few subglacial geothermal areas (Fig. 2) and occasionally during short-lived eruptions. In about 4% of the area of Vatnajökull ice cap (8100 km2) geothermal activity eternally affects the ice flow and basal drainage of meltwater. During the period 1992 to 2005, more than 90% of the ablation within these areas was basal melting while less than 10% of the melting took place during two volcanic eruptions (1996 and 1998). Volcanic ...

The aim of the article is to present a proposal for standardizing the naming of the Quaternary stratigraphic units in Polish and English. Despite the historic changes, most Quaternary stratigraphic names are derived from geographical regions, rivers, towns, and geological sites where sediments of a specific age have been identified. Some names were also adapted from stratigraphic divisions of other European countries. It is common practice to write the names of Quaternary stratigraphic units in Polish in capital letters. However, this contradicts the practice for pre-Quaternary stratigraphic units, which are always written in lowercase in Polish but start with a capital letter in English. In order to comply with standard geological conventions, it is recommended here that the names of Quaternary stratigraphic units are written in lowercase in Polish and in uppercase in English, where possible using the adjectival form (with the-ian suffix) in the latter.

A hydrostratigraphical approach to support environmentally safe siting of a mining waste facility at Rautuvaara, Finland Based on the construction of a detailed sedimentological model, hydrostratigraphy and local groundwater/surface water flows, this paper analyses the Niesajoki river valley as a suitable area for the expansion of a tailings facility, associated with the nearby Hannukainen (Cu, Au, Fe) mine, Finnish Lapland. Three different glacial/interglacial cycles were identified from the sedimentary observations and, optical stimulated luminescence (OSL) datings showed them to be of Early to Late Weichselian in age. Two groups of hydro-stratigraphical units were identified from hydraulic conductivities. The first, fluvial deposits, lie in the centre of the valley along the valley axis, and are the main aquifers. The second, till group, with lower conductivities, are located on the flanks of the valley. The thickness and complexity of sediments varied across the study area. To the E/SE of the valley, sediments are thick (~40 m), and more complex., In contrast the S/W/NW of the area, sediments are thinner (~10 m) and more simple. Groundwater is found to flow towards the centre of the valley and along its axis, where a bedrock controlled divide forms two groundwater basins. Based on the results of this research, it is suggested that any future expansion of the tailings facility should be restricted to the western and southern side of the valley, where waters are more manageable.

Late Pleistocene glaciations in Beringia included rapid expansion of valley glaciers directly after the last interglacial interval (marine isotope stage (MIS) 5e). Glaciation during MIS 4 is referred to as the Early Wisconsin in North America and the Zyryan in northeastern Russia. With the exception of the Alaska Range and Chugach/St. Elias Mountains, the MIS 4 glacial ice caps and mountain glacier complexes throughout much of Beringia were considerably more extensive than during the subsequent Late Wisconsin/Sartan glaciation in MIS 2.

New op ti cally stim u lated lu mi nes cence (OSL) ages show that sandy de pos its over lain by Late Weichselian subglacial till in cen tral Lat via are of Early to Mid dle Weichselian age. The finer chro no log i cal res o lu tion of un con sol i dated sed i ment de po sition in the Cen tral Lat vian Low land (CLL) re mains rel a tively un stud ied, and here we pro vide a first char ac teri sa tion of the depos its with re spect to their age. Three OSL ages rang ing be tween 84 ± 9 ka and 112 ± 11 ka sug gest that the de pos its stud ied in the CLL are of Early Weichselian age (MIS 5). We found no Mid dle Weichselian de pos its in the CLL, and as sume that any such youn ger sed i ments might have been eroded dur ing the ad vance of the Zemgale Lobe in the Late Weichselian. One site, in the ice-mar ginal zone ad ja cent to the interlobate area, has nev er the less de pos its dated to 44 ± 10 ka cor re spond ing to the Mid dle Weichselian (MIS 3). Our re sults are com pat i ble with ex ist ing ESR ages on three sets of Portlandia arctica shells from the cen tral part of the low land; the shells had been in cor po rated into gla cial de pos its dur ing later gla cial ad vances. Fi nally, our find ings largely sup port ice-free con di tions dur ing the Early and Mid dle Weichselian in the mid dle and south ern part of cen tral Lat via.

Chronology of the Last Deglaciation in the Southeastern Baltic Region on the Basis of Recent OSL Dates The study of the deglaciation chronology in the south-eastern Baltic Region belonging to the outer zone of the last Pleistocene glaciation has a long history. The Finnish investigator H. Hausen (1913) who worked in the north-western portion of the East-European Plain at the beginning of the 20th century was the first to attempt a reconstruction of the course of glacial retreat during the last glaciation. At that time investigators had no physical dating methods and the time scale based on varvometric method, introduced by the Swedish geologist G. de Geer (1912) who divided the deglaciation history of Scandinavia into Daniglacial, Gotiglacial and Finiglacial, each of which had different palaeoglaciological conditions. During last decades different dating methods, including 14C, ESR, luminescence methods and 10Be techniques have been used, but they could not help essentially improve ...

Successively smaller glacial extents have been proposed for continental Eurasia during the stadials of the last glacial period leading up to the Last Glacial Maximum (LGM). At the same time the large mountainous region east of Lake Baikal, Transbaikalia, has remained unexplored in terms of glacial chronology despite clear geomorphological evidence of substantial past glaciations. We have applied cosmogenic 10Be exposure dating and optically stimulated luminescence to establish the first quantitative glacial chronology for this region. Based on eighteen exposure ages from five moraine complexes, we propose that large mountain ice fields existed in the Kodar and Udokan mountains during Oxygen Isotope Stage 2, commensurate with the global LGM. These ice fields fed valley glaciers (>100 km in length) reaching down to the Chara Depression between the Kodar and Udokan mountains and to the valley of the Vitim River northwest of the Kodar Mountains. Two of the investigated moraines date to the Late Glacial, but indications of incomplete exposure among some of the sampled boulders obscure the specific details of the post-LGM glacial history. In addition to the LGM ice fields in the highest mountains of Transbaikalia, we report geomorphological evidence of a much more extensive, ice-cap type glaciation at a time that is yet to be firmly resolved.

The glacial river Skeidará was continuously monitored for solute chemistry during the years 1971 and 1972 in which period ajökulhlaup of 3.2 krrd volume took place in the river. In addition, other glacial rivers in Iceland issuing from subglacial volcanic or hydrothermal areas have been monitoredfrom time to time. The article describes the solute chemistry of the rivers Skeidará and Skaftá, offering an interpretation of the hydrothermal systems beneath Vatnajökull responsible for the jökulhlaups. In conclusion some points are made regarding the prediction of jökulhlaups by the chemical monitoring of glacial rivers. The dissolved load of the rivers Skeidará and Skaftá can be traced to three sources, i.e. solutes contained in the precipitation, those derived from the dissolution of the suspended load, and those having a hydrothermal origin. The analyses of the burst water can be corrected for the nonhydrothermal components permitting evaluation of the composition of hydrothermal Jluids. The analyses allow an estimalion of (1) the temperature of the Grímsvötn geothermal system in theyears prior to the jökulhlaups 1972 and 1982, (2) the dilution of the hydrothermal fluid by melt water and (3) water seeping into the system from other sources, and (4) the power of the system. The calculated temperature of the geothermal componenl of the 1972 hlaup was 10TC, that of the 1982 hlaup 192PC. The thermal energy in Grímsvötn was 4160 MW príor to 1972 and 5590 MWprior to 1982; this change could be the result of a minor eruption in Grímsvötn in 1972. It is shown that the Grímsvötn system is dominated by hydrothermal water whereas that of the Skaftá source is dominated by steam.

Till geochemistry has been widely used as a mineral exploration method in glaciated terrain. Applying this exploration method in regions affected by multi-phase glacial ice flows requires a good understanding of dispersal processes involved with each ice flow trajectory. The West Iznogoudh (WIZ) showing occurs in a region of thin to moderate glacial cover with a wide array of ice flow trajectories.The landforms and surface materials of the Point Lake map sheet (86H) are the result of glaciation that flowed in a general westward direction from the Keewatin Sector of the Laurentide Ice Sheet. Recent fieldwork confirmed the earliest ice flow direction to be 220-230, with a short-lived intermediate flow in the northwest direction (approximately 340) and a strong, sustained flow to be in the 287 direction. Rock samples were collected from outcrop at the WIZ showing to define the source trace element geochemical signature. Preliminary petrographic analysis indicates pyrite, chalcopyrit...

The transport of Stonehenge's bluestones has long sparked debate in British prehistory, with contrasting hypotheses attributing their presence to either Neolithic human transport or glacial deposition. This paper compares two critical pieces of evidence: the bullet-shaped "Brian John Boulder" found in situ at Craig Rhos-y-felin in north Pembrokeshire, and the "Newall Boulder," a similarly shaped rhyolite clast excavated at Stonehenge in 1924 [1]. A detailed analysis of their morphology, surface features, weathering, associated debris, and contextual geological and archaeological evidence suggests that both boulders are incompatible with long-distance glacial transport. Petrographic and geochemical analyses support a direct connection between the two sites, reinforcing the argument for deliberate Neolithic extraction and transportation of the bluestones from the Preseli Hills to Stonehenge.

This paper analyses the glacial evolution of the Pas Mountains, in the Eastern Cantabrian Mountains, the glacial landforms and deposits by geomorphological mapping, electric and seismic surveys, and dating intramorainic peat bog and till deposits. The external morainic complex (S-I) shows a glacial extension maximum before 29.150-28.570 cal a BP. A second glacial advance and equilibrium (S-II) have been studied in the entire massif, with glaciers reaching similar positions to the previous phase. Finally, two phases (S-III and S-IV) with very small glaciers developed in the cirque. The last equilibrium glacial phase has been attributed to Late Pleistocene cold phases, previous to Tardiglacial ones. Dating in the Pas Mountains are in agreement with previous dating in the Cantabrian Range and bears out the existence of a glacial maximum, previous to the European LGM.

L'une des caractéristiques géomorphologiques de la plupart de ces vallées est l'existence d'une dépression morphologique du substratum dans les parties moyennes et terminales, interprétée comme la conséquence de l'érosion glaciaire. Dans tous les cas, on observe une architecture litho-stratigraphique commune Bordonau et al., 1989 ; représentée par trois unités géoélectriques : une unité inférieure très épaisse, avec des résistivités électriques basses (70 -200 Ohms par mètre), qui traduit la présence de matériaux fins considérés comme d'origine lacustre ; une unité intermédiaire, moins épaisse, avec des valeurs de résistivité plus élevées (400 -800 Ohms par mètre), pouvant être interprétée comme un système fluvio-deltaïque pro-glaciaire et une unité géoélectrique supérieure, avec des valeurs de résistivité très variables (100 -1500 Ohms par mètre), constituée de sédiments alluviaux subactuels. La comparaison des données de type géophysique et géomécanique (sismique à réfraction et essais pressiométriques) montre que l'unité intermédiaire, considérée comme d'origine fluvio-deltaïque, présente des valeurs de vitesse sismique anormalement élevées, ainsi que de hautes valeurs de consolidation. Cette observation effectuée pour la première fois dans la vallée d'Andorre montre des remarquables corrélations entre les hautes vitesses sismiques et les valeurs élevées de consolidation, ainsi que la très nette corrélation entre les hautes valeurs de consolidation et les tills sous-glaciaires. Elle permet d'interpréter l'unité intermédiaire comme essentiellement glaciaire et de remettre en question le modèle simple d'une séquence de comblement lacustre et deltaïque proposé jusqu´à maintenant.

During the Chile triple junction (CTJ) cruise (March–April 1997), EM12 bathymetry and seismic reflection data were collected in the vicinity of the Chile triple junction (45‐480S), where an active spreading ridge is being subducted beneath the Andean continental margin. Results show a continental margin development shaped by tectonic processes spanning a spectrum from subduction‐erosion to subduction‐accretion. The Andean continental margin and the Chile trench exhibit a strong segmentation which reflects the slab segmentation and the Chile triple junction migration. Three segments were identified along the Andean continental margin: the presubduction, the synsubduction, and the postsubduction segments, from north to south. Both climate‐induced variations of the sediment supply to the trench and the tectonic reorganization at the Nazca‐Antarctica plate boundary involving postsubduction ridge jump are the two main factors that control the tectonic regime of this continental margin. A...

We present geomorphic, stratigraphic, and chronological data acquired along the General Carrera-Buenos Aires (GCBA) glacial lake located along a major morphological incision across the Andes. Complementing relevant available data, relative chronology of morphoclimatic records together with 18 10 Be Cosmic Ray Exposure (CRE) ages allow constraining the timing of the Patagonian ice-sheet fluctuations since the LGM. It improves the knowledge of the Patagonia climate evolution in the 46-48°S area, and allows documenting the uplift rates (glacial rebound) for the past ~7-9 ka. The first major ice lobe retreat occurred after 17.3 ± 0.6 ka and has likely continued during the ACR from ~12.9 to 14.5 ka. Between ~12.9 ka and ~10.9 ± 1.3 ka, the General Carrera Lake evolved as an endorheic basin. Terraces T4 to T1 (top to bottom) have recorded abrupt lake regressions likely controlled by rainfall deficit. They have accumulated in the time interval ~17.3-12.3 ka (maximum limits). Two glacial readvances at ~10.9 ± 1.3 and ~7.9 ± 1.1 ka marked a major climate change that led the lake to be ice-dammed again. A major transgression occurred subsequently that have flooded the previously accumulated terraces. Since then, a pervasive regression has steered the GCBA Manuscript Click here to download Manuscript: DOC 3 NEW TEXT SEPT 2015.doc Lake to the situation at Present. The highest shoreline of the transgression is used as a passive marker in order to quantify the magnitude and character of the regional deformation. At 72°30' W, the GCBA Lake area uplifted (glacial rebound) at a rate between 15 to 33.5 mm.yr - -1 during the past ~7.9 ± 1.1 ka. We infer that the high uplift rate mainly originates from the North Patagonian icefield ice loss.

Some authors have questioned whether the bluestone megaliths present at the Stonehenge Neolithic stone circle were transported from their source area in north Pembrokeshire, over 200 km to the west, by ice, rather than humans. There is scant evidence for either hypothesis and much debate on the matter since the 1990s has involved the so-called 'Newall boulder', a stone collected in 1924 by Lt-Col Hawley. Initial studies considered the boulder to be a glacial erratic and hence supported the ice transport hypothesis. More recent work discounted this interpretation and proposed that the boulder was a piece of rhyolite debitage, itself derived from a broken-up monolith, most likely Stone 32d, originally sourced from Craig Rhos-y-Felin, in north Pembrokeshire although this has been challenged in a recent study. This paper aims to clarify the record regarding previous studies on the Newall boulder and samples taken from it for analysis and to correct errors of fact introduced into the current literature. Petrographic, automated SEM-EDS analysis and portable XRF investigation (including new analyses) relating to the characteristics and composition of the Newall boulder are presented, supporting (a) the interpretation that its original source was Craig Rhos-y-Felin, in north Pembrokeshire and (b) that there is no evidence to support an interpretation that it is a glacial erratic. In addition, it is shown that the overall non-sarsen lithological assemblage at Stonehenge is restricted, supporting derivation by human activity from a limited number of sites, predominantly from west Wales, but also NE Scotland, and not derived from glacial erratics.

The Late Ediacaran to Cambrian Sierras Bayas Group (Villa Mónica, Cerro Largo, Olavarría and Loma Negra Formations) and the Cerro Negro Formation, exposed along the Tandilia system in the province of Buenos Aires (Argentina) were revisited and studied paleomagnetically. Our results supersede those of for the La Tinta Formation (old stratigraphic name of these units). Three hundred and twenty-eight samples were collected from forty-four sites in gently folded to subhorizontal strata distributed along the whole stratigraphic succession. Detailed paleomagnetic study comprised systematic stepwise demagnetization by both AF and thermal methods, the latter being generally the most effective in isolating the characteristic remanence. Different magnetic components were defined from different units of the succession. Besides a recent, probably viscous, secondary component (component A), the most widespread magnetic remanence (component B) is a dual-polarity post-tectonic secondary remanence. This component, carried by both hematite and magnetite, corresponds to that originally determined by and previously interpreted as primary. This component found in all carbonatic rocks of Villa Mónica and Loma Negra Formations as well as in several claystones and siltstones of the Olavarría Formation do not pass conglomerate and regional tilt tests. The mean in situ direction of component B is Dec: 359.8 • , Inc: -63.3 • , n: 85 samples, k: 24, ␣95: 3.2 • and yields a paleomagnetic pole virtually identical to the previous one of Valencio and colleagues. It also matches those recently determined from secondary magnetizations in carbonatic and clastic Ediacaran units exposed in Uruguay.The pole positions suggest a Late Permian-Triassic age as the more likely for the acquisition of component B and reveal the presence of a widespread remagnetization event that affected very large areas of the Rio de la Plata craton. Despite this widespread event, some clastic units (claystones, marls) apparently escaped remagnetization. A pretectonic, dual polarity, mean remanence (Dec: 28.7 • , Inc: 56.1 • , n: 17 samples, k: 15, ␣95: 9.5 • ) was isolated from the latest Ediacaran-Early Cambrian Cerro Negro Formation (component C). In addition, the Ediacaran Olavarria Formation recorded another apparently ancient remanence, although no field test is available. Its direction (component D) is at Dec: 350.9 • , Inc: 47.3 • , n: 13 samples, k: 37, ␣95: 7.0 • . Siltstones and claystones of the Ediacaran Cerro Largo Formation were carriers of a characteristic remanence (component E) that shows a better directional grouping after bedding correction, although the field test is not statistically significant, and yield a mean corrected direction at: Dec: 73.7 • , Inc: -36.6 • , n: 11 samples, k: 15, ␣95: 12.1 • . Finally, a purple horizon of marls on top of the Villa Mónica Formation associated with weathering processes before deposition of the Colombo diamictite, was carrier of a characteristic remanence that attained a better grouping after bedding correction, but again with no statistical significance. This direction (component F) was at Dec: 43.4 • , Inc: -36.3 • , n: 7 samples, k: 45, ␣95: 9.1 • . Components C-F are interpreted as ancient magnetizations associated either to postdepositional or early to late diagenesis. Mean geomagnetic poles computed from these components fall on the apparent polar wander path for the Rio de la Plata craton from around 600 to 520 Ma, in a correct stratigraphic order and with ages consistent with the most likely ages (or slightly younger) of the different sampled units. These results confirm the already proposed Ediacaran to Cambrian APWP for the Rio de la Plata craton, indicating that it remained at intermediate to low latitudes during most of the

The ichnogenus Psammichnites herein restricted to Psammichnites gigas is based on comparison of morphology, feeding behaviour, contrast between the burrows and the host rock and possible producers. The record of siphonal activity as a "snorkel device" is discussed. The diagnosis of the ichnogenus Olivellites now is amended and includes all the records of Psammichnites in the post-Cambrian. Olivellites is now documented in successions other than the classical tidal flat deposits facies of the Carboniferous of the USA. We propose

The sedimentary basins in the Continental Rift of Southeastern Brazil (CRSB) provide an opportunity for ichnological analyses due to its well-known facies relationships and paleoenvironmental interpretations. This study reports invertebrate trace fossils from the Neogene fluvial deposits (Floriano Formation) and applies integrated ichnological and facies analyses to reconstruct the environmental conditions recorded in this lithostratigraphic unit. Fieldworks revealed a rich ichnofauna in the Floriano Formation, whose facies associations have been interpreted as indicative of meandering river environments. Four sedimentary facies were identified, including bioturbated sandstone, horizontally stratified sandstone, laminated sandstone, and mudstone. Six ichnogenera were identified, Arenicolites, Beaconites, Camborygma, Palaeophycus, Skolithos, and Taenidium. Those ichnogenera occur as Skolithos, Taenidium, and Beaconites ichnocoenoses. The Skolithos ichnocoenosis is primarily represented within sand bar deposits, indicating arthropod colonization in abandoned channels. The Taenidium ichnocoenosis, which is observed within mudstone layers and presents Camborygma burrows, suggests transitional environments between aquatic and subaerial conditions, locally with high water table levels. The Beaconites ichnocoenosis indicates changes in substrate consistency associated with progressive desiccation and extended exposure time. Therefore, the identified ichnocoenoses, combined with the analysis of physical sedimentary structures, suggest generally humid conditions during colonization by invertebrates of the meandering river deposits of the Floriano Formation.

Winged porphyroclasts are often used as kinematic or strain indicators in shear zones. In particular, it has been suggested that the geometry of d-clasts in mylonites can give information about the rheological behaviour of the matrix around the Ž . clast Passchier et al., 1993 . We tested this hypothesis with a numerical finite element simulation of the flow field of a viscous matrix around a relatively rigid clast. Power-law viscous flow properties of the matrix with stress-exponents of 1 Ž . linear viscous , 3 and 5 were tested, as well as three different sets of approximately simple shear boundary conditions, which are relevant to experimental andror natural situations. The simulations show that the flow field is primarily determined by the boundary conditions. The stress-exponent is of secondary importance. In general, the different boundary conditions produce two types of flow fields about the rigid clast: an eye-shaped flow field and a bow-tie shaped flow field. The former is produced by boundary conditions that approximate simple shear applied at an infinite distance from the rigid clast, and the latter is produced by boundary conditions which are equivalent to a shear box or ring shear apparatus. Although both the shear-box and ring-shear boundary conditions produce bow-tie flow patterns, the wing geometries which result from the flow patterns for these two cases can be significantly different. The geometry of the wings that develop on a d-clast is a direct function of the flow field around the clast. For linear and Ž non-linear rheologies, only the ring-shear boundary conditions produce wings that show ''stair-stepping'' i.e. wings that are . parallel but not in the same plane . In natural shear zones, d-clasts both with and without stair-stepping are observed. In comparing geologic observations with experimental or numerical modelling, it is essential to understand which boundary conditions are appropriate.

The northern Lyngen Peninsula in Troms, northern Norway, displays a suite of glacial and periglacial landforms that describe both a complex interaction of geomorphological processes and its history of deglaciation during the Late Weichselian and Holocene. These features include: cirque and valley glacier moraines, relict ice-cored moraines, rock avalanches, rock glaciers, a protalus rampart, and other talus-derived landforms. Morphological relationships of landforms within the three valleys of Strupskardet, Veidalen and Reindalen were studied in detail; using a combination of geographic information systems (GIS), aerial photograph interpretation, and field research. Seven distinctive glacial stages (comprised of up to 13 minor phases) were identified, and presented as a series of maps that describe the chronology of deglaciation within the study area. Relative-age dating of moraines was performed with a Schmidt hammer, which measured the rebound value (R-value) from boulder surfaces. This technique was found to be an effective tool that offered additional insight into the age of moraines and other landforms. Equilibrium line altitudes (ELA) were also calculated for reconstructed ice limits to elucidate the effects of local topography and regional climatic conditions on glacier formation.

The rapid proliferation of 5 GHz wireless communication technologies has made them essential for high-speed
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their effects on wireless networks, and proposes robust countermeasures. Through code-based simulations in Python and Bash,
this study models the relationship between jammer power and network degradation. We conclude by recommending techniques
for mitigating these threats and ensuring secure wireless communication.

The region of Ribeirão Preto City located in São Paulo State, southeastern Brazil, is an important sugarcane, soybean and corn producing area. This region is also an important recharge area (Espraiado) for groundwater of the Guarany aquifer, a water supply source for the city and region. It has an intercontinental extension that comprises areas of eight Brazilian states, as well as significant portions of other South American countries like Argentina, Uruguay, and Paraguay, with a total area of approximately 1,200,000 Km 2 . Due to the high permeability of some soils present in this region, the high mobility of the herbicides and fertilizers applied, and being a recharge area, it is important to investigate the potential transport of applied fertilizers to underlying aquifer. The cultivation sugar cane in this area demands the frequent use of nitrogen as fertilizer. This research was conducted to characterize the potential contamination of groundwater with nitrogen in the recharge area of groundwater. Seven groundwater sample points were selected in the Espraiado stream watershed, during the years of 2005 and 2006. Samples were collected during the months of March, July, and December of each year. Three replications were collected at each site. Groundwater was also collected during the same months from county groundwater wells located throughout the city. The following six wells were studied: Central, Palmares, Portinari, Recreio Internacional, São Sebastião, and São José. Nitrate water samples were analyzed by Cadmium Reduction Method. No significant amount of nitrate was found in the recharge, agricultural, area. However, nitrate levels were detected at concentrations higher than the Maximum Concentration Level (MCL) of 10mg/L in downtown, urban, well located away from agricultural sites with no history of fertilizer or nitrogen application.

Iceberg calving at glacier termini results in mass loss from ice sheets, but the associated fracture mechanics is often poorly represented using simplistic (empirical or elementary mechanics-based) failure criteria. Here, we propose an advanced Mohr-Coulomb failure criterion that drives cracking based on the visco-elastic stress state in ice. This criterion is implemented in a phase field fracture framework, and finite element simulations are conducted to determine the critical conditions that can trigger ice cliff collapse. Results demonstrate that fast-moving glaciers with negligible basal friction are prone to tensile failure causing crevasse propagation far away from the ice front, while slow-moving glaciers with significant basal friction are likely to exhibit shear failure near the ice front. Results also indicate that seawater pressure plays a major role in modulating cliff failure. For land terminating glaciers, full thickness cliff failure is observed if the glacier exceeds a critical height, dependent on cohesive strength 𝜏 c (H ≈ 120 m for 𝜏 c = 0.5 MPa). For marine-terminating glaciers, ice cliff failure occurs if a critical glacier free-board (Hh w) is exceeded, with ice slumping only observed above the ocean-water height; for 𝜏 c = 0.5 MPa, the model-predicted critical free-board is Hh w ≈ 215 m, which is in good agreement with field observations. While the critical free-board height is larger than that predicted by some previous models, we cannot conclude that marine ice cliff instability is less likely because we do not include other failure processes such as hydrofracture of basal crevasses and plastic necking.

Vengono presentati e discussi i risultati ottenuti a seguito di una campagna spettroradiometrica effettuata nel giugno 2003 sul Monte Etna. Scopo della campagna era quello di realizzare una prima indagine sulle caratteristiche di riflettanza dei depositi piroclastici recenti prodotti dall'attività eruttiva 2002-2003 e sulle colate più antiche. A tal fine sono state predisposte delle schede per l'acquisizione dei dati e sono stati selezionati siti rappresentativi delle unità vulcaniche etnee. Dai risultati ottenuti si evince che i depositi piroclastici recenti, indipendentemente dalla granulometria e dal tipo di materiale che li costituisce, presentano valori di riflettanza costanti. Le colate di tipo pahoehoe hanno valori di riflettanza maggiori, sebbene la caratterizzazione spettrale delle colate più antiche non possa prescindere dalla presenza di prodotti di alterazione e delle coperture vegetali che ne influenza l'entità.

Historically, drier types of wetlands have been difficult to characterize and are not well researched. Nonetheless, they are considered to reflect the precipitation history with little, if any, regard for possible relation to groundwater. Two seasonal coastal wetland types (wet prairie, sedge meadow) were investigated during three growing seasons at three sites in the Lake Michigan Basin, Wisconsin, USA. The six seasonal wetlands were characterized using standard soil and vegetation techniques and groundwater measurements from the shallow and deep systems. They all met wetland hydrology criteria (e.g., water within 30 cm of land surface for 5% of the growing season) during the early portion of the growing season despite the lack of appreciable regional groundwater discharge into the wetland root zones. Although root-zone duration analyses did not fit a lognormal distribution previously noted in groundwater-dominated wetlands, they were able to discriminate between the plant communities and showed that wet prairie communities had shorter durations of continuous soil saturation than sedge meadow communities. These results demonstrate that the relative rates of groundwater outflows can be important for wetland hydrology and resulting wetland type. Thus, regional stresses to the shallow groundwater system such as pumping or low Great Lake levels can be expected to affect even drier wetland types.

Surrounding and within the town of Loon Lake, Stevens County, Washington State, is a field of giant current ripples. Due to their concave, generally north/south orientation, the drainage to the east has been the traditionally interpreted source of the flood water. This flood is regarded as overflow from the large flood that inundated the Deer Park Basin in early or pre-Wisconsin time and created the giant current ripples northeast of Deer Park . Since the publication of LIDAR images of the Loon Lake area, additional insights regarding the direction and sources of water flow can be interpreted. This paper will point out that the gap at the south end of the Loon Lake body of water was likely an additional source of water input into the Loon Lake area during this flood and merged with the flow from the east.

Withdrawal of the Late Wisconsinan Laurentide ice sheet from coastal Maine is recorded by a complex assemblage of glacial and glacial-marine sediments and morphologic features (end moraines, deltas, subaqueous fans). This paper summarizes the work of many people who, for the past decade, have studied the glacial geology of the Maine coastal region and have contributed to the development of a general picture of final deglaciation of the State of Maine and adjacent areas. Detailed examination of stratigraphic sections throughout the Maine coastal zone has led to the development of a working model for glacial-marine sedimentation during Late Wisconsinan deglaciation of the state. Four principal glacial-marine lithofacies types and five major lithofacies associations have been defined to characterize the glacial-marine sedimentary succession in the coastal zone, and to provide the basis for the glacial-marine depositional model. In general terms, this model depicts final deglaciation of the coastal zone as follows: (a) establishment of marine-based ice conditions during deglaciation; (b) deposition of sediments by both ice-dominated and waterdominated processes; (c) rapid sedimentation in an environment characterized predominantly by subaqueous fan formation and remobilization of sediments by gravity flow mechanisms; ( d) still stands of the retreating ice front to produce partial-and fully-developed deltas; (e) periodic fluctuations of the ice margin (grounding line) to produce end moraines; and (f) gradual transition from marine-based to terrestrially-based deposition of glaciogenic sediments. End moraines of a variety of forms outline the general pattern of ice retreat from the coastal zone. The most important of these moraines are DeGeer moraines. Both large stratified moraines and DeGeer moraines record minor fluctuations (or stillstands) of the ice margin and either depositional or glacial-tectonic thickening of the "normal" sedimentary succession. The chronology of deglaciation of the coastal zone is currently an issue of some debate. Several chronologies and their implications are discussed. Although there is presently no clear consensus on the timing of the events of final deglaciation, it is now generally accepted that ice retreat from the coastal zone was not interrupted by significant glacial readvance.

4) GEARH d.o.o., Slovenia The Dinaric karst is one of the most typical karst areas in the world where the karst phenomena are widespread and well-developed. This area is also particularly interesting because its mountainous parts experienced glacial conditions during the Quaternary cold stages and hence a glaciokarst type of landscape developed. The Snežnik Mountain (1796 m asl) in the southern part of Slovenia is a high karst plateau that shows significant glacial modification with the majority of glacial deposits being deposited between 900 and 1200 m asl. Here we present a study of the Praprotna draga closed depression, which is one of the largest karst depressions in Snežnik with an area of approximately 3.4 km2 and a maximum depth of 140 m. Its western slopes are characterized by undulated moraine morphology and alluvial fans starting from bellow moraines are filling the entire floor of the depression. This study aims to improve understanding of spatial and chronological relationship between glacial, paraglacial and ice-proximal outwash dynamics in the Dinaric karst environment. Therefore, we reveal the origin, geometry and age of deposits in Praprotna draga using geomorphological, sedimentological, geophysical and cosmogenic dating approaches. The spatial distribution and geometry of moraines point to two glacial advances with an altitudinal difference of about 140 m. This two-phase interpretation is also supported with the electrical resistivity tomography (ERT) measurements performed along one of the alluvial fans, which show a diamicton-like sedimentary body buried below alluvial deposits. Another ERT profile was measured over the moraine ridge in order to obtain the significant resistivity values of till deposits in this area and compare them with resistivity values of diamicton buried bellow alluvium. Alluvial deposits in the mid fan zone were sampled for cosmogenic 36Cl analysis of amalgamated carbonate pebbles. The depth profile of 36Cl concentrations leads to a minimum age of the alluvial deposit of 11.7 ± 1.2 kyr when assuming no denudation and up to an age of 13.9 ± 2.2 kyr for 30 mm/yr of soil denudation. This suggests the alluvial material was deposited during Late glacial period, in transition from glacial to non-glacial conditions, and subsequently allow us to interpret the timing of the final glacier retreat in the Snežnik Mountain.

Successful artificial neural network analyses of the lithology data -prediction of either sandstones or shale were obtained. These were performed in the youngest (Pliocene, Pleistocene and Holocene) sediments in Sava Depression, Croatian part of the Pannonian Basin, and the input data was based on well log curves (spontaneous potential, shallow and deep resistivity curves). These analyses were successfully preformed in 20 wells of which in two, the training and validation of the networks was made. Such obtained lithology data was used for the construction of lithofacies maps which clearly show the distribution of the overall thickness of sandstone bodies and their number. Palaeotransport directions and areas with thicker sandstone interval for possible gas accumulations can also be observed in the constructed maps. The main influx of sediment was from the NE trough a channel which coincides with recent structural low defined by the absence of Pliocene outcrops while the thickest sandstone intervals can be delimited to the SW part of the mapping area.

GRAINS BY SCANNING ELECTRON MICROSCOPY. Zs. Kapui, A. Kereszturi, S. Józsa, Cs. Király, Z. Szalai, G. Újvári, 1 MTA Research Centre for Astronomy and Earth Sciences, Institute for Geological and Geochemical Research (kapui.zsuzsanna@csfk.mta.hu), MTA Research Centre for Astronomy and Earth Sciences, Konkoly Observatory Eötvös Loránd University, Department of Petrology and Geochemistry, MTA Research Centre for Astronomy and Earth Sciences, Geographical Institute.

This study uses luminescence and 14C accelerator mass spectrometry procedures to date relevant glaciofluvial and glacial deposits from the south-central and southeastern Pyrenees (Andorra–France–Spain). We distinguish two types of end-moraine complexes: (1) those in which at least a far-flung moraine exists beyond a frequently nested end-moraine complex (the most common) and (2) those in which a close-nested end moraine encompasses at least two glacial cycles. Both types formed within six distinctive glacial intervals: (1) A penultimate glacial cycle during Marine Oxygen Isotope Stage (MIS) 6 and older glaciofluvial terraces occurred beyond the range of the luminescence dating method. (2) An early glacial advance in MIS 5d (~97 −15/+19 ka) was followed by glacial retreat during MIS 5c (< 91 ± 9 ka). (3) The last maximum ice extent (LMIE) was in early MIS 4 (~74 ± 4.5 ka). (4) Unexpectedly, glaciers thinned during the second half of MIS 3 (~39 −6/+11 ka). (5) During the MIS 3–2 tr...

This paper analyses the glacial evolution of the Pas Mountains, in the Eastern Cantabrian Mountains, the glacial landforms and deposits by geomorphological mapping, electric and seismic surveys, and dating intramorainic peat bog and till deposits. The external morainic complex (S-I) shows a glacial extension maximum before 29.150-28.570 cal a BP. A second glacial advance and equilibrium (S-II) have been studied in the entire massif, with glaciers reaching similar positions to the previous phase. Finally, two phases (S-III and S-IV) with very small glaciers developed in the cirque. The last equilibrium glacial phase has been attributed to Late Pleistocene cold phases, previous to Tardiglacial ones. Dating in the Pas Mountains are in agreement with previous dating in the Cantabrian Range and bears out the existence of a glacial maximum, previous to the European LGM.

Glacial features were described for the first time on the Galicia Moun- tains, a mountain range separating the lakes of Ohrid and Prespa in Mace- donia. The geomorphological mapping of part of this range allowed to document the existence of frontal and lateral moraines, as well as trimlines, cirques and polished rocks. These glacial features allowed the reconstruc- tion of the original topography of the glaciers that deposited the frontal moraines. The Equilibrium Line Altitude (ELA) of three different phases of expansion was calculated (ca. 1850 m, ca. 2000 m and 2130 m a.s.l.) through the Area-Altitude Balance Ratio (AABR) method, and correlated with the values available for the Balkan region and northern Greece. An at- tribution to Last Glacial Maximum (LGM) and Lateglacial (Oldest and Younger Dryas) was argued for the glacial phases of Galicica Mountains, in agreement with the ELAs of dated moraines in the region, as well as in the Apennines and Maritime Alps. Through the extrap...