The origins of Antarctic rock glaciers: periglacial or glacial features?

Abstract

In extensively glaciarized permafrost areas such as Northern Victoria Land, rock glaciers are quite common and are considered postglacial cryotic landforms. This paper reveals that two rock glaciers in Northern Victoria Land (at Adélie Cove and Strandline) that are located close to the Italian Antarctic Station (Mario Zucchelli Station) should have the same origin, although they were previously mapped as Holocene periglacial landforms and subsequently considered ice‐cored and ice‐cemented rock glaciers, respectively. In fact, by integrating different geophysical investigations and borehole stratigraphy, we show that both landforms have similar internal structures and cores of buried glacier ice. Therefore, this kind of rock glacier is possibly related to the long‐term creep of buried ice rather than to permafrost creep alone. This interpretation can be extended to the larger part of the features mapped as rock glaciers in Antarctica. In addition, a high‐reflective horizon sub‐parallel to the topographic surface was detected in Ground Probing Radar (GPR) data over a large part of the study area. Combining all the available information, we conclude that it cannot be straightforwardly interpreted as the base of the active layer but rather represents the top of a cryo‐lithological unit characterized by ice lenses within sediments that could be interpreted as the transition zone between the active layer and the long‐term permafrost table. More generally, knowledge of the subsurface ice content and, in particular, the occurrence of massive ice and its depth is crucial to make realistic and affordable forecasts regarding thermokarst development and related feedbacks involving GHG emissions, especially in the case of cryosoils rich in carbon content. Copyright © 2017 John Wiley & Sons, Ltd.

Insights in a remote cryosphere: A multi method approach to assess permafrost occurrence at the Qugaqie basin, western Nyainqêntanglha Range, Tibetan Plateau

“…Next critical issue for the estimation of the lower occurrence of probable permafrost whether the huge resistivities observed on profile A (Figure 8, A, black lines) indicates ice or not. In general, subsurface material determination without additional cross-validating techniques by other geophysical method or borehole data remains uncertain (Hauck and Kneisel, 2008;Guglielmin et al, 2018). Therefore, the geomorphological knowledge of the study area is essential for an interpretation of the subsurface: In this case, the measured resistivity values of Profile A (Figure 8) of up to 100 kΩm are consistent with both till or ice-poor permafrost (Schrott and Sass, 2008).…”

Contextualizing lobate debris aprons and glacier-like forms on Mars with debris-covered glaciers on Earth

“…Janke et al, 2015; Monnier and Kinnard, 2015), and Antarctica (e.g. Bockheim, 2014; Guglielmin et al, 2018; Swanger et al, 2010). See also the recent review by Jones et al (2019a).…”

The Spatio-Temporal Variability of Frost Blisters in a Perennial Frozen Lake along the Antarctic Coast as Indicator of the Groundwater Supply

“…In particular, structure from motion (SfM) photogrammetry has been largely used especially for improving beach 3D reconstructions [3,4], although on Antarctic coastal areas SfM is usually used for monitoring sea ice, e.g., [5], ecosystems, e.g., [6] or moss beds, e.g., [7], but rarely for topographic changes, e.g., [8] or periglacial landforms mapping, e.g., [9]. Nevertheless, in the ice-free coastal areas of continental Antarctica, periglacial and cryotic features such as thermal-contraction-crack polygons, ice-wedges, perennially frozen lakes including frost mounds [10,11] and rock glaciers [12] are widespread.…”