Abstract This work consists of the sedimentological, mineralogical, and geochemical characterization of eight marine sediment cores collected in the Central Bransfield Basin, along a transect between the South Shetland Islands to the Antarctic Peninsula and its correlation to the sedimentary and oceanographic processes of the area. A chemical characterization based on X-ray fluorescence dispersive spectrometry was implemented to obtain geochemical data of the marine sediment while the minerals were identified by X-ray diffraction. The study allowed to classify the cores into three groups according to their sediment source and chemical and mineralogical characteristics. The joint assessment of the geochemical and mineralogical signature of the sediment has confirmed that the elemental ratios Ti/Ca and Fe/Ca can be applied as proxies in the reconstitution of the terrigenous contribution to the Central Bransfield Basin if we consider the sedimentary contribution of the volcanic edifices present in the region. The Fe/K ratio associated with the Chemical Index of Alteration reinforced an increase in the degree of weathering near South Shetland Island, which is also pointed out by other authors in studies on climate change mainly in the subantarctic islands. The trend of temperature increase implies the importance of monitoring the region. sedimentological area Xray X ray diffraction characteristics TiCa Ti Ca FeCa Fe region FeK K Island islands

Abstract This study aims to investigate the glacier shrinkage and recent proglacial environment in King George Bay, Antarctica, since 1988 in response to climate change. Remote sensing data (SPOT, Sentinel, Landsat and Planet Scope images) were applied to glacial landforms and ice-marginal fluctuations mapping. Annual mean near-surface air temperature reanalysis solutions from ERA-Interim were analyzed. Moraines and glaciofluvial landforms were identified. The Ana Northern Glacier has the highest retreat value (3.64 km) (and area loss of 31%) in response to higher depth in frontal ice-margin and reveal ocean-glacier linkages. The Ana South Glacier changed from a tidewater glacier to land-terminating after 1995, and had an outline minimum elevation variation of 89 meters, a shrinkage of 0.63 km, and a new proglacial subaerial sector. The Ana South Glacier foreland had recessional moraines (probably formed between 1995 and 2022), lagoons, and lakes. There are many flutings in low-relief environments. The 1980-1989, 1990-1999, 2000-2009, 2010-2019 anomaly plots concerning to the 1980-2019 average for atmospheric temperature, are shown to be a driver of the local glacial trends.

Abstract This study investigates the transient snowline (TSL) altitude for summer 2020, as well as glacial area loss in King George Island Icefields since 1988 using Sentinel-1 and 2 and Landsat Thematic Mapper (TM) imagery. Trends and anomalies in atmospheric temperature, U-wind, and V-wind were examined using ERA5 solutions. Results show the wet-snow zone corresponds to values of ≤ -13dB, and 44.3% of the glacial area is located above the TSL (≥ 300 m). Glacial area for 2020 is 999.95 km², and losses in the period represent 104.9 km² (error <1%) – a retreat of 3.17 km² / year. Glaciers in Keller Peninsula and Bellingshausen Dome lost the most area (28% and 17%, respectively) and did not have a TSL in 2020; followed by Warszawa (15%), Kraków (13%), and Eastern (10%), where the TSL was verified. Percentage area loss values increased with decreases in dimensions, area above TSL, and maximum elevation. Calving glaciers with ice-flow toward deeper and steeper submarine sectors (Bransfield Strait) exhibited greater glacier variations. The trend in warming atmospheric temperature was greater in the Bransfield Strait than in the Drake Passage. TSL and retreat difference between glaciers were influenced by climatic and ocean input, as well as multiple environmental factors.

Resumen Con el retroceso de los glaciares en la Antártica marítima y los escenarios de cambio climático, es necesario comprender los procesos geomorfológicos que actúan en estas áreas recientemente expuestas. El propósito del artículo es presentar el Método geomorphon aplicado a la Antártica (Método Geomorphon aplicado a Antártica-MGA), para el mapeo de las formas de relieve en las áreas libres de hielo de la Isla Rey Jorge. La evaluación de la clasificación se realizó con base en la interpretación de MDE y algunos trabajos de campo realizados en los anos 2015 y 2016. Los elementos del relieve identificados por el MGA se relacionaron con las formas erosivas y depositacionales de génesis glacial, por una parte, de macro escala como valles, crestas, picos y, por otra, de mesoescala, como canales fluvio glaciales, morrenas de avance y de retroceso, así como los de génesis paraglacial y litoral. Se identificaron morrenas frontales que avanzan en todas las áreas, a excepción del sistema paraglacial del glaciar Ecology que, junto con los valles en U mapeados, indican la antigua dirección del flujo de los glaciares y los lugares donde había mayor espesor de hielo. La identificación de estas formas es una contribución para los estudios que evalúan la sucesión de cambios en el paisaje, relacionados con el retroceso reciente de los sistemas glaciares, lo que demuestra el potencial de MGA. Ideas destacadas: Artículo de investigación sobre el mapeo automático de los accidentes geográficos de origen glacial, marino y paraglacial, utilizando el método innovador llamado Método geomorphon aplicado a la Antártica en las áreas libres de hielo de la Isla Rey Jorge, Islas Shetlands del Sur.

Resumo Com a retração de geleiras na Antártica marítima, e os cenários de mudanças climáticas, faz-se necessário compreender os processos geomorfológicos atuantes nessas áreas recentemente expostas. O artigo apresenta o Método de Geomorphon aplicado à Antártica (Geomorphon Method aplicado à Antártica - em diante ОМА) voltado ao mapeamento de formas de relevo nas áreas livres de gelo da Ilha Rei George. A avaliação da classificação foi realizada com base na interpretação dos MDE e nos trabalhos de campo realizados em 2015 e 20i6. Os elementos de relevo identificados pelo GMA foram relacionados com as formas erosivas e deposicionais por um lado de macro escala de gênese glacial, como vales, aretês, horns, e por outro lado de meso escala como canais glaciofluviais, morainas de avanço e de recessão, e ainda as de gênese paraglacial e marinha. Morainas de avanço frontais foram identificadas em todas as áreas, com exceção do sistema paraglacial da geleira Ecology, e juntamente com os vales em u mapeados, indicam a antiga direção de fluxo das geleiras, e locais onde havia maior espessura de gelo. A identificação dessas formas contribui para estudos que avaliam a sucessão de mudanças na paisagem com a recente retração dos sistemas glaciais, comprovando a potencialidade do GMA. Ideias destacadas: Artigo de pesquisa sobre o mapeamento automático de formas de relevo de origem glacial, marinha e paraglacial, a partir do método inovador chamado Geomorphon Method aplicado à Antártica para as áreas livres de gelo da Ilha Rei George, Ilhas Shetlands do Sul.

Abstract With the retraction of glaciers in maritime Antártica, and the climate change scenarios, it is necessary to understand the geomorphological processes at work in these recently exposed areas. The purpose of the article is to present the Geomorphon Method for Antártica (Geomorphon Method Revised to Antártica-GMA) applied to the mapping of landforms in the ice-free areas of King George Island. The classification evaluation was carried out based on the interpretation of the MDE and on the field work carried out in 2015 and 2016. The relief elements identified by the GMA were related to the erosive and depositional forms of the glacial genesis macro scale, as valleys, aretes, horns and meso-scale, such as glaciofluvial channels, moraines of advance and recession, and even those of paraglacial and marine genesis. Frontal advancing moraines were identified in all areas, except for the Ecology glacier paraglacial system, and together with the mapped U-valleys, they indicate the old direction of flow of the glaciers, and places where there was greater thickness of ice. The identification of these forms contributes to studies that evaluate the succession of changes in the landscape with the recent retraction of glacial systems, proving the potential of GMA. Main ideas: Research article on the automatic mapping of landforms of glacial, marine and paraglacial origin, using the innovative method called Geomorphon Method Applied to Antártica, in the ice-free areas of the King George Island, South Shetlands Islands.

Abstract This work aims to analyze and compare the sedimentological data of Ellsworth Mountains, West Antarctica: Patriot/Independence Hills and Union Glacier, and how sedimentological data can be used to infer sediment entrainment. Particular attention was concentrated on morainic deposits. Remote sensing data was used in the identification of deposits and the ice flow; granulometric, morphoscopic, and geochemical analyses were applied to investigate the sedimentary origin and transport history. Sediment rich in Si Al, Fe, and Ca predominate in Independence Hills and Rossman Cove but Ca prevails in Elephant Head. CIA indicated low values, which depict low chemical weathering processes. X-ray diffraction reveals the presence of minerals that constitute the local rocks in the Union Glacier area, and from the unexposed basement rocks in Independence Hills. Principal Component Analysis and Cluster Analysis results suggest the sediment is related to the local rocks in the Union Glacier and distinct exotic sources in Independence Hills, associated with far-traveled sediment. It is also observed the influence of distinct processes of entrainment sediment on its granulometric and morphoscopic characteristics.

Abstract This research aims to investigate sediment cores from a glaciomarine environment based on their petrophysical parameters to elucidate lithological and sedimentary issues, as well as to identify a geophysical signature based on their parameter’s response. To achieve this objective, six marine sediment cores were collected in the Central Bransfield Basin - Antarctica, the lengths ranging from 1.5 to 5.2 meters in water depths ranging from 304 to 1463 meters. The cores were submitted to different analyses and values from density, magnetic susceptibility, electrical resistivity, p-wave velocity, total gamma radiation, silt, clay and sand contents, and mean grain size for each core location were considered. Four large lithologies were identified according to their geological and geophysical characteristics. The first group is subglacial deformation till (GC16); the second is massive diamicton (GC13 and GC12), the third group is composed of diamictons from the basin (AM10) and lower slope (GC09); the fourth lithological group is composed of siliceous mud from an upper slope location (GC06A). The characteristics recorded across Central Bransfield Basin (from South Shetlands Islands to Antarctic Peninsula) highlighted the relationship between the lithological content and associated depositional processes with the geophysical proprieties as density and magnetic susceptibility.

Abstract Monitoring and inventorying proglacial lakes in the Maritime Antarctica region is essential for understanding the effects of climate change on these environments. This study uses Landsat images to create a map of lakes in ice-free areas of the South Shetlands Islands (SSI) for 1986/89, 2000/03 and 2020, and verification of patterns of change in lake areas and numbers. Normalized water difference index (NDWI) products, image segmentation, field records, and cartographic products from other studies were used to validate the results. Results show a 60% increase in the number of lakes from 1986/89 to 2000/03; and a 55% increase from 2000/03 to 2020. There was a 52% increase in lake areas from 1986/89 to 2000/03; a 79% increase from 2000/03 to 2020; and a 173% increase from 1986 to 2020. From 1986 to 2020, the most significant changes were a decrease in the average elevation and distance from glaciers and an increase in distance from the sea. In 2020, SSI lakes were predominantly coastal and ice-marginal, with an E and S orientations, flat surfaces, and a low declivity.

Abstract This study investigated the terrestrial and submarine geomorphology and glacial landform records in the Martel inlet (King George Island) using a multi-resolution topobathymetric data based on seismic, multibeam surveys and terrestrial satellite datasets (REMA DEM). Geomorphometric analysis provided glacial landforms and sedimentary processes interpretation. The submarine sector has a mean depth of 143 m, a maximum depth of 398 m, and most of it has a low slope (0°–16°). Steep slopes (>30°) are found along the mid-outer sectors transition area. The continental shelf was divided into inner fjord (49 m depth), middle fjord (119 m), and outer fjord (259 m), based on depth, elevation and slope. The topobathymetric digital model provides evidence of geomorphological contrasts between these zones in the fjord’s seafloor and subaerial environments. A prominent morainal bank in the transition between the inner and middle parts marks the limit of a past stationary stage of the Dobrowolski-Goetel ice margin. Streamlined glacial lineations demonstrate an NE-SW past ice flow direction and a wet-based thermal regime. The combined analysis of submarine and subaerial landforms enable the understanding of the former glacier configuration and its deglaciation history.

Abstract The analysis of glacial and ice-marginal systems may contribute to understanding the impact of climatic change. The aim of this study is to investigate changes in the glacial, proglacial and paraglacial system in response to the Collins glacier retreat, between the Little Ice Age (LIA) and 2070. Glacial geomorphological mapping reveals landforms that are diagnostic of a terrestrial-terminating glacier in the past. Glacial and the proglacial systems were mapped to evaluate the ice-marginal evolution. The field measurement, satellite imagery, granulometric and morphoscopic sedimentary analysis, and geomorphological data are analyzed. The Collins glacier surface topography has been surveyed by DGNSS during 11 years (1997/98-2008/09) and for glacier area estimation in 2030, 2050 and 2070 CE. The Collins glacier lost 1.4 km² in the period LIA-2018. Under an atmospheric warming scenario, using the temperature melt index model the glacier will lose approximately 5% of its total area until 2030 (0.90 km²), 21% (3.60 km²) by 2050, and 35% (5.90 km²) by 2070 CE. Four sectors in the proglacial zone are identified: Sector 1 displays changes on the front of the glacier since the LIA, a push moraine in only one sector, presence of flutings and moraines of recession. Sector 2 showed shrinkage around 100 meters in the period LIA-2018, presenting recessional and push moraines of about 10 meters of height. Sector 3 showed 350 meters of the shrinkage since the LIA, and recessional moraines, and absence of the push moraines. Sector 4, showed 1500 meters of the shrinkage since the LIA, a push moraine of about 12 meters high. This behavior that occurs since the LIA allows validating the future scenario model. The ice-free areas could expand 1,4 km² by the end of 2070 decade if considered since LIA. However, it should be noted that if the glacier continues to retreat, the system will be subject to hydrological and sedimentary readjustments at various stages in the future.

Resumen El análisis de los sistemas glaciales y marginales al hielo puede contribuir para la comprensión del impacto de los cambios climáticos. De esta forma, el objetivo de este estudio es investigar los cambios en el sistema glacial, proglacial y periglacial en respuesta al retroceso del glaciar Collins, entre la Pequeña Edad del Hielo (PEH) y 2070. La Península Fildes, parte sur de la isla Rey Jorge (latitud entre 62° 08' y 62° 14' S y longitud entre 59°02' e 58°51' O), es una de las primeras áreas a quedarse libre del hielo en el archipiélago de las Shetland del Sur después del Último Máximo Glacial. La elección por esta área de estudio en la isla Rey Jorge se justifica por la facilidad de se accender a ella para la realización de trabajos de campo y también porque hay investigaciones previas sobre ella que indican la retracción de los glaciales. Para evaluar la evolución marginal del hielo se mapearon los sistemas glacial y proglacial. Se interpretaron y se delimitaron las etapas de retracción desde la PEH por la posición de las morrenas de recesión y por la cronología establecida por imágenes de satélite. Se utilizaron imágenes Landsat de los sensores TM, ETM+ y OLI referentes a las fechas 03/01/1986, 27/02/1988, 28/01/1989, 19/01/2003, 17/03/2015 y 29/04/2018 para establecer los valores de retracción del glaciar Collins. Para elaborar el mapeo geomorfológico actual se analizaron datos de trabajos de campo realizados en 2013, 2014 y 2015; imágenes de satélite Quickbird de febrero de 2008; análisis granulométricos y morfoscópicos de sedimientos recolectados en los principales accidentes geográficos del area proglacial del glaciar Collins y datos del Modelo de Elevación Digital TanDEM-X. La topografia de la superfície del glaciar Collins fue obtenida por DGNSS a lo largo de 11 años (1997/98-2008/09) y se utilizaron los datos para calculcular el área y el espesor aproximados del glaciar en 2030, 2050 y 2070. Acerca de los resultados, se destaca que el glaciar Collins perdió 1,4km2 en el período PEH. En un escenario de calentamiento atmosférico, utilizando el modelo de índice de derretimiento, el glaciar perderá aproximadamente el 5% de su área total hasta 2030 (0,90 km²), el 21% (3,60 km²) hasta 2050 y el 35% (5, 90 km²) hasta 2070. Se identificaron cuatro sectores en la zona proglacial: el sector 1 presentó cambios enfrente del glaciar desde la PEH, presencia de flutings y morrenas de recesión. El sector 2 presentró una retracción alrededor de 100 metros en el período PEH-2018, con el depósito de morrenas de recesión de cerca de 2 m de altura y de morrenas de empuje de unos 10 metros de altura. El sector 3 presentó 350 metros de retracción desde el PEH, formación de morrenas de recesión y ausencia de morrenas de empuje. El sector 4 presentó 1.500 metros de retracción desde el PEH, formando una morrena de empuje de cerca de 12 metros de altura. Este comportamiento, que ocurre desde la PEH, permite validar el modelo de escenario futuro. Las áreas libres de hielo pueden expandirse 1,4 km² en el período PEH-2070. Considerando el proceso hidrológico y sedimentológico, las áreas más dinámicas serán los sectores 1 y 2, debido al retroceso más rápido del glaciar. Cabe destacar que la zona recientemente libre de hielo del glaciar Collins también estará sujeta a procesos periglaciales que podrán ser analizados solamente mediante una evaluación sistémica, considerando interacciones y cambios en los sistemas hidrológico, sedimentario y biológico. Sin embargo, se estima que los procesos periglaciales probablemente predominarán a lo largo de la primera etapa posterior al retroceso del glaciar Collins, presentando un área inestable, con una alta concentración de sedimentos que forman accidentes geográficos como morrenas, eskers, flutings y canales entrelazados capaces de transportar material para la actual zona proglacial. El área proglacial actual probablemente cambiará debido a la reducción del suministro de agua de deshielo y a una mayor distancia de los glaciales. Cabe señalar que el modelo del índice de derretimiento no considera las variaciones en la temperatura del aire, lo que obviamente puede generar diferencias en los escenarios propuestos. Sin embargo, se destaca que los resultados encontrados en esta investigación son consistentes con los valores de retracción de volumen y de área de los glaciares de la isla Rey Jorge y de la Península Antártica encontrados en otros artículos. Se destaca, también, que los resultados encontrados en esta investigación están de acuerdo con los valores de retracción de volumen y de área de los glaciares de la Isla Rey Jorge y de la Península Antártica encontrados en otros artículos.

En este trabajo se presenta la metodología empleada para muestras de hielo y nieve y su análisis de tipo químico, con el objeto de reconstruir tanto la historia climática como la composición química de la atmósfera a partir de testigos de hielo obtenidos por perforación del manto de hielo. El derretimiento y sub-muestreo de los testigos (secciones de 1 metro) fue realizado en uno sistema de derretimiento continuo y automatizado (desarrollado por investigadores del Climate Change Institute (Universidad de Maine, EUA) que permite obtener simultáneamente muestras para análisis geoquímicos, incluyendo la determinación de elementos traza por Espectrometría de Masas por Plasma Acoplado Inductivamente (ICP-MS), del contenido iónico por Cromatografía Iónica (IC) y la determinación de isótopos estables de hidrógeno y oxígeno (δ18O y δD) por Espectrometría de Masas de Proporción Isotópica (IR-MS).Este trabajo se basa en el análisis de 2 de 6 testigos colectados, de los cuales se tiene parte de los datos obtenidos en el análisis químico realizado por cromatografía iónica (concentraciones iónicas promedio) para los testigos IC-5 (42.5 m; 82°30.5'S, 79°28'W) e IC-6(36 m; 81°03'S, 79°51'W), correspondientes a los primeros 10 m de profundidad; los cuales aún están siendo analizados.

Two ice cores, IC-5 (82°30.5'S, 79°28'W, 950 m a.s.l.; 42.5 m) and one IC-6 (, 81°03'S, 79°51'W, 750 m a.s.l; 36 m) were collected as part of the 2004/2005 Chilean (with Brazilian collaboration) ITASE traverse from Patriot Hills to the South Pole. Mean accumulation rates in water equivalent calculated for the upper 10 m at the IC5 site is 0.37 m a-1 and 0.33 m a-1 at the site IC6. Coregistered samples (1595 for IC5 and 1368 for IC6) were obtained using a discrete continuous melter system with a pure nickel melt head at the Climate Change Institute under class 100 clean room conditions. All samples were analysed by ion chromatography (IC), inductively coupled plasma field mass spectrometry (ICP-MS), and stable isotope ratio mass spectrometry (IRMS).

Esse estudo interpreta os perfis acústicos de subfundo e modelos 3D submarinos de alguns fiordes adjacentes ao Campo de Gelo Patagônico Sul, Chile. As bacias aprofundadas mostram a morfologia irregular e distintas formas associadas ao sistema sedimentar de zonas de grounding line, de línguas de gelos flutuantes. Refletores acústicos exibem duas fácies principais: caóticas e estratificadas, segundo sua configuração interna e geometria externa. Os sedimentos provavelmente foram depositados durante a deglaciação durante o Holoceno. A geometria dos depocentros e as características dos refletores acústicos mostram evidências da influência da batimetria e da topografia pré-existentes. Devido às grandes profundidades das bacias, as margens terminais podem ter sido um misto de condições flutuantes e aterradas no fundo marinho, embora possa predominar o regime glacial temperado.

This study interprets acoustic sub-bottom profiles and submarine 3D models of some of fjords adjacent to Campo de Hielo Patagónico Sur (Southern Patagonian Icefield), Chile. The overdeepened fjord basins show irregular morphology and distinctive landforms associated with a grounding-line, ice tongues and icebergs sedimentary system. Acoustic reflectors display two main facies: chaotic and laminated, according the internal reflection configuration and the external geometry. The sediments probably were deposited during the Holocene deglaciation, as shown by the visible reflectors of sub-bottom profiler. The geometry of the depocenters and the acoustic reflectors characteristic show evidence of pre-existing topography and bathymetry influence. Due to the great water depths of the fjord basins, terminal margins may have a mix of floating and grounded cliff behaviour, albeit the predominant temperate glacial regime.