Geomorphological processes and frozen ground conditions in Elephant Point (Livingston Island, South Shetland Islands, Antarctica)

Abstract

Elephant Point is an ice-free area in the SW corner of Livingston Island (Maritime Antarctica). The retreat of Rotch Dome glacier during the Holocene has exposed a land area of 1.16 km 2 . Up to 17.3% of this surface has become ice-free between 1956 and 2010. A detailed geomorphological mapping of this ice-free environment was conducted in late January 2014. A wide range of active periglacial landforms show that periglacial processes are widespread. From the glacier to the coast four different geomorphological areas are identified: proglacial environment, moraine complex, bedrock plateaus and marine terraces. In situ measurements of the thawed soil depth show evidence of the widespread frozen ground conditions in the area. Field observations of permafrost exposures suggest that these frost conditions may be related to a soil permafrost regime, almost down to sea level. The activity of penguin colonies and elephant seals has created minor geomorphological features in the raised marine terraces. Here, several archaeological sites related to early human colonization of Antarctica were also found in natural shelters.

Geomorphology and landforms distribution in selected ice-free areas in the South Shetland Islands, Antarctic Northern Peninsula region

“…Studies on the glacial history of the South Shetland Islands point out the deglaciation of some capes and peninsulas at around 11 to 9.5 ka BP. On Fildes Peninsula the deglaciation begun between 11 and 9 ka ago (Watcham et al, 2011), and on King George Island (Potter Peninsula) between 11.9 and 5.9 ka while on Byers Peninsula an age of 8.3-5.9 ka has been determined (Toro et al, 2013, Oliva et al, 2016. A regional advance between 6 and 4.5 ka BP (Hall, 2010;Michalchuck et al, 2009) has been detected after a period with less cold conditions between 8.2 and 5.9 ka (Milliken et al 2009).…”

“…During the last decade a considerable amount of soil, permafrost and geomorphological studies have been carried out in this region which is becoming warmer and wetter (Michel et al, 2006(Michel et al, , 2012(Michel et al, , 2014Navas et al, 2006Navas et al, , 2008Simas et al, 2006Simas et al, , 2007Simas et al, , 2008Schaefer et al, 2007;Serrano et al, 2008;Vieira et al, 2008Vieira et al, , 2010Vieira et al, , 2014Francelino et al, 2011;López-Martínez et al, 2012;Moura et al, 2012;Balks et al, 2013;Bockheim et al, 2013;Oliva and Ruiz-Fernández, 2015;Simas et al, 2015;Oliva et al, 2016). The relationship between landforms and soil distribution (Balks et al, 2013;Michel et al, 2014) and the distribution and changes of vegetation related to ice-free areas Pereira and Putzke, 2013;Guglielmin et al, 2014;Vieira et al, 2014) have been studied in detail in some areas.…”

Propuesta de protección ambiental para un enclave libre de hielo de la Antártida Marítima (Punta Elefante, isla Livingston) = Proposal of environmental protection for an ice-free area in the Maritime Antarctic (Elephant Point, Livingston Island)

“…La respuesta geoecológica al cambio ambiental post-glaciar depende, por consiguiente, del tiempo de exposición del terreno a las condiciones de ausencia de hielo glaciar, así como a la propia topografía del lugar y a la variabilidad climática imperante. Tomando en consideración las evidencias geomorfológicas, así como también una perspectiva comparativa con el área libre de hielo de la península Byers, cabe asumir que el retroceso del domo glaciar Rotch en Punta Elefante es de edad holocena (Oliva et al, 2014;Ruiz-Fernández y Oliva, 2016. Sin embargo, este retroceso no fue lineal -en términos cronológicos-, sino que cabe contemplar la existencia de varias pulsaciones glaciares que generaron el extenso sistema morrénico compuesto por varios arcos (dando lugar, por tanto, a una morrena poligénica).…”

“…Las plataformas rocosas litorales constituyen uno de los elementos geomorfológicos más antiguos de la península (Oliva y Ruiz-Fernández, 2016). La larga exposición a condiciones no glaciares ha conllevado una densa cobertura de estas plataformas por tapetes de líquenes.…”

“…Estas áreas constituyen sectores terrestres que fueron expuestos durante los últi-mos siglos, como es el caso de las playas levantadas superiores, que presentan una abundante y diversa gama de comunidades vegetales (Oliva y Ruiz-Fernández, 2016). La superficie horizontal de las playas levantadas próximas a la costa favorece el uso intensivo por parte de diversas especies de focas, pingüinos y otra avifauna.…”