Effect of Climate on Morphology and Development of Sorted Circles and Polygons

Abstract

Sorted circles and polygons are widespread features of periglacial landscapes, but the controls on their development remain poorly understood, impeding their use as palaeoenvironmental indicators. We investigate the relationship of sorted circles and polygons to altitude in the northern Billefjorden area, central Svalbard. The patterns occur in two distinct elevation zones, below 200–250 m asl and above 600 m asl. The higher‐elevated patterns have smaller diameters and shallower sorting depths due to a thinner active layer at higher elevations, suggesting that sorted patterns can indicate climate conditions and ground thermal state when the patterns initiated. Geology is believed to be of less importance for pattern morphology in the study area, causing only its fine‐scale variations. The pattern diameter‐to‐sorting depth ratios have a median value of 3.57, consistent with previous studies and theoretical models of patterned‐ground formation involving circulation mechanisms. Large‐scale sorted patterns may develop over centennial timescales in this high‐Arctic environment. They are probably not in equilibrium with present‐day climate conditions and have probably formed throughout the Holocene. Copyright © 2017 John Wiley & Sons, Ltd.

The role of rapid glacier retreat and landscape transformation in controlling the post‐Little Ice Age evolution of paraglacial coasts in central Spitsbergen (Billefjorden, Svalbard)

“…As we showed in this study, the bedrock outcrops that cross local coastal plains play an important role in controlling the sediment delivery to the coastal zone. The geomorphology of the valley systems that surround the bay is dominated by periglacial processes (e.g., Uxa, Mida, & Křížek, ) and paraglacial sediment reworking of glacial sediments deposited by the Late Weichselian glaciation and the LIA glacier advance (e.g., Ewertowski, ; Pleskot, ; Rachlewicz, ). Petuniabukta glaciers were part of a large ice stream complex that drained the Late Weichelseian ice sheet via Billefjorden into Isfjorden (Eccleshall, Hormes, Hovland, & Preusser, ; Landvik et al, ).…”

Detection and Delineation of Sorted Stone Circles in Antarctica

“…Their characterization and monitoring can provide useful information about the underlying processes if circles are currently active [7,8] and also about the past climatic conditions that allowed their formation/evolution [9][10][11][12][13]. In addition, besides their evident geomorphic importance and their use as paleoclimatic indicators, the periodic burial and exhumation of geological materials may also play an important role in the soil carbon cycle in connection to permafrost conditions [6].…”

PERICLIMv1.0: A model deriving palaeo-air temperatures from thaw depth in past permafrost regions

“…The second assigns current climatic thresholds of active features to complex relict periglacial assemblages to deduce the most plausible palaeo-climate (Ballantyne and Harris, 1994). Such empirical interpretations, however, largely rely on flawed assumptions because suitable analogues for past periglacial environments are rare due to substantial differences in solar insolation between mid and high latitudes (Williams, 1975;French, 2017), and even if they can be found, active features present there may have developed under climatic conditions different from those which prevail at the present time (Uxa et al, 2017;Ballantyne, 2018). Climatic controls on most periglacial features are therefore poorly established, usually implying broad ranges of conditions (Washburn, 1980;Harris, 1982Harris, , 1994Karte, 1983;Wayne, 1983;Ballantyne and Harris, 1994;Huijzer and Isarin, 1997;Ballantyne, 2018), which also relates to the fact that the features partly depend on other 1 https://doi.org/10.5194/gmd-2020-5 Preprint.…”