Browsing by Author "Soteres, Rodrigo L."

Now showing 1 - 6 of 6
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    Cosmogenic nuclide moraine chronologies from Patagonia: A globally synchronic response of mountain glaciers during Termination 1?
    (2023) Soteres, Rodrigo L.; Sagredo T., Esteban; Kaplan, M. R.; Martini, M. A.; Riquelme, F. M.; Schaefer, J. M.
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    Geophysical characterization of the El Cervunal kame complex (Sierra de Gredos, Iberian Central System): Insight of infill geometry and reconstruction of former glacial formations
    (2021) Granja-Bruna, Jose Luis; Turu, Valenti; Carrasco, Rosa M.; Munoz-Martin, Alfonso; Ros, Xavier; Fernandez-Lozano, Javier; Soteres, Rodrigo L.; Karampaglidis, Theodoros; Lopez-Saez, Jose Antonio; Pedraza, Javier
    Geological and geophysical studies in complex valley troughs provide a key record for the reconstruction of paleoenvironmental conditions during the Quaternary. Here we present a study of the sedimentary infill of the El Cervunal kame complex or El Cervunal trough (Sierra de Gredos, Iberian Central System) by means of a combined interpretation of near-surface geophysical techniques supported by geomorphological and borehole data. A set of 1D and 2D near-surface geophysical methods, including electrical (Vertical Electrical Sounding and 2D Electrical Resistivity Tomography), seismic (2D Seismic Tomography and 1D Refraction Microtremor) and Magnetic Resonance Sounding techniques, were used to test their applicability in providing better insight on the infill nature and geometry. Because of greater sensitivity and higher resolution and coverage achieved with resistivity methods, the electrical resistivity has proven to be the most informative physical parameter, while seismic and magnetic resonance methods were complementary. The sedimentary infill was classified into three geophysical units and five sub-units with their geological interpretation. Unit 1 consists of a postglacial sedimentary sequence and includes alluvial-plain and alluvial-fan deposits. Units 2 and 3 below the postglacial unit were interpreted as glacial sequences including kame (glacigenetic and fluvio-glacial) and morainic deposits, respectively. Subsoil information combined with the geomorphological data enabled the partial reconstruction of the map-view geometry of the morainic bodies at the El Cervunal trough. The results suggest a complex evolution of the study area where erosive-sedimentary processes dominate, but also structural factors should be considered. At least five well-differentiated stages can be established to explain the occurrence of the trough infill: preglacial, maximum glacial extension, trough obturation, glacial retreat and periglacial-postglacial.
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    Glacial geomorphology of the central and southern Chilotan Archipelago (42.2 degrees S-43.5 degrees S), northwestern Patagonia
    (TAYLOR & FRANCIS LTD, 2022) Soteres, Rodrigo L.; Sagredo, Esteban A.; Moreno, Patricio, I; Lowell, Thomas, V; Alloway, Brent, V
    We present a geomorphic map of the glacial landforms associated with the Golfo Corcovado ice lobe in northwestern Patagonia. Built upon prior studies, our map elaborates on the central and southern sectors of Isla Grande de Chiloe and neighboring islands. Through a combination of remote sensing techniques and exhaustive fieldwork, we identified a suite of ice-marginal, subglacial, and glaciofluvial features created by the Golfo Corcovado ice lobe during four maxima within the last glacial cycle, in none of which the ice-front reached the Pacific coast of Isla Grande de Chiloe. Our mapping builds a foundation and provides insights for future interdisciplinary research on the Late Quaternary sequence of glacial and paleoclimatic events in this key sector of northwestern Patagonia.
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    Glacial geomorphology of the Strait of Magellan ice lobe, southernmost Patagonia, South America
    (2020) Soteres, Rodrigo L.; Peltier, Carly; Kaplan, Michael R.; Sagredo, Esteban A.
    We present a geomorphic map of the landforms created by the Patagonian Ice Sheet during the local Last Glacial Maximum and perhaps prior glaciations in southernmost Patagonia. Building on prior work, the new mapping focuses in unprecedented detail on the right lateral and frontal landforms formed by the Strait of Magellan ice lobe. We produced the map using aerial orthophotography, Sentinel-2 and SPOT satellite imagery, ALOS PALSAR digital elevation model and fieldwork to ground-truth preliminary interpretations. We delineate at least five glacial events defined by a sequence of moraine drifts and associated glaciofluvial features. In contrast to previous studies, we propose the Magellan ice lobe extended similar to 65 km farther, to the Primera Angostura peninsula, during the local Last Glacial Maximum. Our study provides a new context to establish a precise glacial chronology of the Magellan ice lobe during the last glacial cycle in the middle-high latitudes of the Southern Hemisphere.
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    Occurrence, residency, and habitat characterization of leopard seals in Chile
    (2024) Borras-Chavez, Renato; Soteres, Rodrigo L.; Gomez-Gonzalez, Gabriela; Martinez, Francisco; Fernandez-Ferrada, Nicolas; Castillo-Aguilar, Matias; Moreno Azua, Fredy; Dougnac, Catherine; Arredondo, Cristobal; Brown, Nicholi; Sperou, Emily S.; Bonin, Carolina A.; Goebel, Michael E.; Guerrero, Alicia I.; Donke, Marcelo; Kienle, Sarah S.
    Leopard seals have traditionally been considered Antarctic predators with a Southern Ocean distribution. Historically, sightings north of the Antarctic Polar Front were considered extralimital. However, recent studies suggest a significant presence of leopard seals in subantarctic regions. Here, we assess the spatial occurrence, residency status, and temporal trends of leopard seals in Chile using historical records, stranding reports, standardized monitoring data, photo-identification (photo ID) catalogs, and sightings from four research expeditions. We also characterize glaciers where sightings are concentrated, identifying glaciological and geomorphic attributes that prolong iceberg residency time, which is linked to high leopard seal concentrations. Based on these attributes, we evaluated other potential suitable glacial habitats in Patagonia. We obtained 438 sighting records of leopard seals from 1927 to 2023. Over the last 15 years, we documented a 4-18% annual increase in stranding events reported to national authorities. Most sightings (75%) were concentrated in two hotspots: National Park San Rafael Lagoon, located in Northern Patagonia, and Parry Fjord in Tierra del Fuego. Using photo ID catalogs, we identified 19 resident leopard seals, including 16 multi-year residents observed between 2010-2023 (10 in San Rafael, 6 in Tierra del Fuego) and 3 potential residents (observed multiple months in the same year in Tierra del Fuego). San Rafael monitoring data showed no inter-annual trend, but seasonal trends were observed. We also provide evidence of breeding in Chile, with records of at least 14 pups born and at least two females giving birth in multiple years. Our habitat characterization suggests that calving flux, fjord sinuosity, and fjord width variation are crucial for prolonging iceberg residency in hotspot areas. Based on these attributes, we identified 13 additional fjords in Patagonia as "very likely" suitable for leopard seals. Our study confirms that Patagonia is part of the species' breeding distribution, shifting the paradigm that leopard seals are merely visitors north of the Antarctic Polar Front. Given the limited number of suitable glaciers in Chile and the potential impacts of climate change, our assessment highlights glacial retreat as a major threat for the ecosystem of this pagophilic marine apex predator in South America.
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    Snow avalanche susceptibility of the Circo de Gredos (Iberian Central System, Spain)
    (2020) Soteres, Rodrigo L.; Pedraza, Javier; Carrasco, Rosa M.
    We present a detailed snow avalanche susceptibility map at scale 1:20,000 of the Circo de Gredos in the Sierra de Gredos (Iberian Central System, Spain). This cirque-shaped landscape is one of the most popular spots for winter sports in the region. However, no snow avalanche activity assessment has been conducted to date. We have, therefore, produced a snow avalanche susceptibility map based on aerial and satellite imagery, newspaper reviews and field work, including avalanche features recognition and interviews with frequent backcountry users. We extracted the spatial distribution of necessary and enhancer factors for triggering slab, wet and loose snow avalanches from a digital elevation model. Finally, calculations to evaluate each snow avalanche type susceptibility were performed using a Geographical Information System. By combining our map collection, we concluded that most of the area in the Circo de Gredos is highly susceptible to snow avalanches, especially slab and wet snow types.