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 to 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.

DFG Project PolarBeach (LI2005/1-1)During two field campaigns (Austral springs 2011 and 2012) the sedimentary architecture of a polar gravel-spit system at the northern coast of Potter Peninsula (Area 4) was revealed using ground-penetrating radar (GPR, Geophysical Survey Systems, Inc. SIR-3000). 47 profiles were collected using a mono-static 200 MHz antenna operated in common offset mode. Trace increment was set to 0.05 m. A differential global-positioning system (dGPS, Leica GS09) was used to obtain topographical information along the GPR lines. GPR data are provided in RADAN-Format, dGPS coordinates are provided in ascii format; projection is UTM (WGS 84, zone 21S).

Supplement to: Heredia Barión, Pablo; Lindhorst, Sebastian; Schutter, Ilona; Falk, Ulrike; Kuhn, Gerhard (2018): 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). Earth Surface Processes and Landforms