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La deglaciación de las áreas libres de hielo de las islas Shetland del Sur (Antártida): ejemplos de Byers (Livingston) y Barton (King George)
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Orientador(es)
Resumo(s)
El proceso de deglaciación de las actuales áreas libres de hielo existentes en la zona de la Antártida marítima
tiene notables repercusiones geomorfológicas y ecológicas. No obstante, la cronología del retroceso glaciar es
aún poco conocida. Éste es el caso de las áreas deglaciadas existentes en las penínsulas Byers (isla Livingston)
y Barton (isla King George). La datación de la base de los sedimentos recuperados en diferentes lagos emplazados
en estas dos penínsulas permite inferir la edad de aparición de cada lago que, integrando el conjunto de
dataciones, posibilita la reconstrucción del patrón espacial y temporal de la deglaciación de estas áreas. Las
técnicas empleadas para el establecimiento de la cronología de los sedimentos de los lagos se han basado en
el uso complementario de dataciones de radiocarbono y termoluminiscencia. En ambas penínsulas la aparición
de superficies libres de hielo se inició durante el Holoceno inferior, en torno a los 8 ka. Las áreas más alejadas
de los casquetes glaciares actuales y las zonas más elevadas de ambas penínsulas (nunataks) fueron las
primeras superficies en quedar expuestas. Durante el Holoceno medio (entre 5 y 6 ka) el sector central de estas
áreas fue progresivamente deglaciado. Durante el Holoceno superior los frentes glaciares permanecieron
circunscritos a la posición que determinan las morrenas frontales actuales, con avances y retrocesos menores.
The process of deglaciation of the present-day ice-free environments in the Maritime Antarctica has profound geomorphological and ecological implications. However, the timing of glacier retreat is still poorly understood. This is the case of the deglaciated areas existing in Byers (Livingston Island) and Barton (King George Island) peninsulas. The dating of the basal sediments collected from different lakes in these two peninsulas allowed inferences of the ages of formation of each lake. The integration of these ages enables the reconstruction ofthe spatial and temporal pattern of deglaciation of these areas. The chronological framework has been establishedusing two complementary techniques: radiocarbon and thermoluminescence dating. In both peninsulas the deglaciation started during the Early Holocene, around 8 ka cal BP. The areas located far away from the current ice domes and the highest peaks in the two peninsulas (nunataks) were the first areas to become ice -free. During the mid- Holocene (5-6 ka cal BP) the central part of these peninsulas was progressively deglaciated. Finally, during the Late Holocene glacier fronts remained confined to the current position defined by the present frontal moraines, with minor advances and retreats.
The process of deglaciation of the present-day ice-free environments in the Maritime Antarctica has profound geomorphological and ecological implications. However, the timing of glacier retreat is still poorly understood. This is the case of the deglaciated areas existing in Byers (Livingston Island) and Barton (King George Island) peninsulas. The dating of the basal sediments collected from different lakes in these two peninsulas allowed inferences of the ages of formation of each lake. The integration of these ages enables the reconstruction ofthe spatial and temporal pattern of deglaciation of these areas. The chronological framework has been establishedusing two complementary techniques: radiocarbon and thermoluminescence dating. In both peninsulas the deglaciation started during the Early Holocene, around 8 ka cal BP. The areas located far away from the current ice domes and the highest peaks in the two peninsulas (nunataks) were the first areas to become ice -free. During the mid- Holocene (5-6 ka cal BP) the central part of these peninsulas was progressively deglaciated. Finally, during the Late Holocene glacier fronts remained confined to the current position defined by the present frontal moraines, with minor advances and retreats.
Descrição
Palavras-chave
Antártida Península Byers Península Barton deglaciación sedimentos lacustres
Contexto Educativo
Citação
Oliva, M., Antoniades, D., Giralt, S., Granados, I., Pla-Rabes, S., Toro, M., Sanjurjo, J. (2016). The deglaciation of the ice-free areas in the South Shetland Islands: examples from Byers (Livingston) and Barton (King George). Cuaternario y Geomorfologia, 30(1–2), pp. 105–118. https://doi.org/10.17735/cyg.v30i1-2.48665.
Editora
Asociación Española para el Estudio del Cuaternario, Sociedad Española de Geomorfología