Reaction of a polar gravel‐spit system to atmospheric warming and glacier retreat as reflected by morphology and internal sediment geometries (South Shetland Islands, Antarctica)

Abstract

Sedimentary architecture and morphogenetic evolution of a polar bay‐mouth gravel‐spit system are revealed based on topographic mapping, sedimentological data, radiocarbon dating and ground‐penetrating radar investigations. Data document variable rates of spit progradation in reaction to atmospheric warming synchronous to the termination of the last glacial re‐advance (LGR, 0.45–0.25 ka BP), the southern hemisphere equivalent of the Little Ice Age cooling period. Results show an interruption of spit progradation that coincides with the proposed onset of accelerated isostatic rebound in reaction to glacier retreat. Spit growth resumed in the late 19th century after the rate of isostatic rebound decreased, and continues until today. The direction of modern spit progradation, however, is rotated northwards compared with the growth axis of the early post‐LGR spit. This is interpreted to reflect the shift and strengthening in the regional wind field during the last century. A new concept for the interplay of polar gravel‐spit progradation and glacio‐isostatic adjustment is presented, allowing for the prediction of future coastal evolution in comparable polar settings. © 2018 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.

Shorter but thicker: analysis of internal growth bands in shells of intertidal vs. subtidal Antarctic limpets, Nacella concinna, reflects their environmental adaptation

“…1). Both P0 and P1 represent coastal rock heads on the outer southern shore of PC, with extended shallow intertidal offshore areas composed of boulders (volcanic rock and glacial moraines, Lindhorst and Schutter 2014;Heredia Barión et al 2019). These boulders are surrounded by a sand and gravel covered intertidal, in which rock pools form during low tides (Fig.…”

“…2). The adjacent sublittoral zone is composed of sandy and rocky bottom (Heredia Barión et al 2019).…”

Discharge of groundwater flow to Potter Cove on King George Island, Antarctic Peninsula

“…Several authors have analysed the quaternary deposits in Potter Peninsula (e.g. John and Sugden, 1971;Birkenmajer, 1998;Del Valle et al, 2002;Wiencke et al, 2008). Tatur and del Valle (1986), who worked in the paleolimnological and geomorphological aspects, and Birkenmajer (1998) proposed that the glacial deposits in Potter Peninsula could be of different glacial episodes along the Quaternary.…”

“…Tatur and del Valle (1986), who worked in the paleolimnological and geomorphological aspects, and Birkenmajer (1998) proposed that the glacial deposits in Potter Peninsula could be of different glacial episodes along the Quaternary. Heredia Barión et al (2019) give a detailed study on the sedimentary archi-U. Falk and A. Silva-Busso: Geohydrology of King George Island in a changing climate tecture and morphogenetic evolution of a polar bay mouth gravel spit system for Potter Cove.…”

“…The shoreline is formed by a gravel coastal cordon that controls an inland lagoon with deposits of fine sand and silt (Heredia Barión et al, 2019). This is a transition zone between the talik and the cryopeg (Silva-Busso, 2009), although the latter is likely to be replaced by a wedge of fresh water coming from the streams due to the magnitude of groundwater flow discharge.…”