Cryostructures in Antarctic Permafrost
Researchers supported by the Astrobiology Science and Technology for Exploring Planets (ASTEP) element of the NASA Astrobiology Program have analysed icy permafrost cores from the McMurdo Dry Valleys of Antarctica. The samples, taken from University Valley, were examined for sediment properties, ground-ice content, types and distribution of cryostructures, and presence of unconformities.
The team found composite cryostructures in the permafrost cores, regardless of whether the samples contained ground-ice from vapour deposition or ground-ice from freezing of snow meltwater. The results indicate that the distribution of cryostructures cannot be used to infer how ground ice was formed. The Dry Valleys of Antarctica are an important site for astrobiologists studying the limits of life on Earth and the potential for life on other worlds. The valleys have long been used as a Mars analog site in which instruments designed for planetary missions are tested. The study highlights unique ground-ice processes that could help scientists better understand the environment of Antarctica’s Dry Valleys, and which could provide markers for similar, potentially habitable environments on planets like Mars.
The paper, “Cryostratigraphy and the Sublimation Unconformity in Permafrost from an Ultraxerous Environment, University Valley, McMurdo Dry Valleys of Antarctica,” was published in the journal Permafrost and Periglacial Processes.
A second paper, “Distribution and origin of ground ice in University Valley, McMurdo Dry Valleys, Antarctica,” was published the journal Antarctic Science. This paper provides an overview of the distribution and origin of ground ice examined by the team across 18 permafrost cores collected in University Valley.
ASTEP was an active element of the Astrobiology Program from 2001 to 2014 and supported investigations focused on exploring Earth’s extreme environments to learn how best to search for life on other planets. The types of projects that were funded by ASTEP are now competed under Planetary Science and Technology from Analog Research (PSTAR).