Landscape evolution and ice-sheet behaviour in a semi-arid polar environment: James Ross Island, NE Antarctic Peninsula

Abstract

Davies, B. J., Glasser, N., Carrivick, J. L., Hambrey, M. J., Smellie, J. S., Nyvlt, D. (2013). Landscape evolution and ice-sheet behaviour in a semi-arid polar environment: James Ross Island, NE Antarctic Peninsula. Geological Society Special Publication.This study of landscape evolution presents both new modern and palaeo process-landform data, and analyses the behaviour of the Antarctic Peninsula Ice Sheet through the Last Glacial Maximum (LGM), the Holocene and to the present day. Six sediment-landform assemblages are described and interpreted for Ulu Peninsula, James Ross Island, NE Antarctic Peninsula: (1) the Glacier Ice and Snow Assemblage; (2) the Glacigenic Assemblage, which relates to LGM sediments and comprises both erratic-poor and erratic-rich drift, deposited by cold-based and wet-based ice and ice streams respectively; (3) the Boulder Train Assemblage, deposited during a Mid-Holocene glacier readvance; (4) the Ice-cored Moraine Assemblage, found in front of small cirque glaciers; (5) the Paraglacial Assemblage including scree, pebble-boulder lags, and littoral and fluvial processes; and (6) the Periglacial Assemblage including rock glaciers, protalus ramparts, blockfields, solifluction lobes and extensive patterned ground. The interplay between glacial, paraglacial and periglacial processes in this semi-arid polar environment is important in understanding polygenetic landforms. Crucially, cold-based ice was capable of sediment and landform genesis and modification. This landsystem model can aid the interpretation of past environments, but also provides new data to aid the reconstruction of the last ice sheet to overrun James Ross Island.Peer reviewe

“Bottomsets” of the lava−fed delta of James Ross Island Volcanic Group, Ulu Peninsula, James Ross Island, Antarctica

“…Spectacular outcrops of lava−fed deltas represent one of the most striking mor− phological features of the James Ross Island (Nelson 1975;Davies et al 2013). This paper demonstrates results of a study of deposits recognised in the bottomset posi− tion (i.e.…”

Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region

“…The annual amplitude of air temperatures exceeds 40°C with summer maxima >10°C and winter minima <-30°C. Precipitation shadow effect caused by Trinity Peninsula (Davies et al, 2013) significantly affects precipitation, mainly in the form of snow during the winter season. The estimated annual precipitation is 400-500 mm (van Lipzig et al, 2004), although high wind speeds cause irregular deposition and significant snow removal from the landscape (Nývlt et al, 2016) and therefore the maximum thickness of snow layer does not exceed 0.3 m in flat areas (Zvěřina et al, 2014;Hrbáček et al, in press).…”

“…The landscape of the Ulu Peninsula has been, besides glacial erosion and accumulation, sculpted by paraglacial and periglacial processes (Davies et al, 2013). Permafrost on Ulu Peninsula is continuous (Bockheim et al, 2013) with an approximate thickness of 67 m according to geoelectrical measurements (Borzotta and Trombotto, 2004).…”

“…Fine-grained calcareous sandstones and siltstones of the Alpha Member and Santa Marta Formation of Late Cretaceous age (Olivero et al, 1986;Crame et al, 1991) form study site. The superficial part is generally weathered to form loose sandy regolith with occasional gravel clasts mostly of James Ross Island Volcanic Group basalts; finer fraction is generally blown away (Davies et al, 2013). Vegetation cover is very scarce with concentration spots mostly along streams, or around seal carcasses (Nývlt et al, 2016).…”

“…While permafrost distribution is known to be continuous on James Ross Island (Davies et al, 2013), it is discontinuous in the lowlands of the Livingston Island turning to continuous in elevations above 150 m (Vieira et al, 2010). The main purpose of this study is the comparative examination of the ground thermal regime on both sites in order to better understand the factors controlling active layer dynamics in the AP region.…”