The Permafrost in the Antarctic Peninsula

Since 1990, the joint Argentine (Instituto Antarctico Argentino, IAA),
Japanese (Institute of Low Temperature Science, ILTS), and, recently,
Italian (Third University of Rome) group "Criologia" has been
concerned with research on cryological and geomorphological aspects in
the northern Antarctic Peninsula area. Sorted nets, circles and
stripes, stone pits, ice-wedge, seasonal frost crack polygons,
gelifluction lobes, ice-cored rock glaciers, protalus lobes, protalus
ramparts, and stone-banked terraces are some of the most conspicuous
cryogenic and periglacial features studied by our research group.

One topic of the research program focuses on determining the
flow regime and mechanisms of different types of rock glaciers (and
protalus lobes), including the "glacier-rock glacier system", called
Lachman II on James Ross Island. A more precise characterization of
these morphological systems results from the determination of surface
flow patterns by tracking marked blocks, more accurately referred to
as fixed stations, and from data of installed local thermo-registering
stations that provide precise values of air mean annual temperature,
ground mean annual temperature, and geothermal gradient. A main rock
glacier and an older rock glacier are morpho-dynamically
distinguished. Considering the geomorphology of the landscape related
to these rock glaciers, they were formed after two recessive glacier
advances, which occurred at 1300 to 1000 and 200 YBP, respectively.

Protalus lobes develop without relation to glaciers at the foot of
scree slopes and look to be ice-cemented. Protalus ramparts are
mentioned for the first time in the Antarctic Peninsula area. Their
genesis is related to protalus lobe formation.

Another topic we studied was related to stone-banked terraces that
develop in Rink Crags, James Ross Island. Stone-banked terraces occur
on a gentle slope (approximately 5 degrees) at the top of these crags
(approximately 450 m above sea level), and reach maximum lengths of about
60 m and widths of about 30 m. The fronts range in height from less
than 0.6 m to as much as 3.5 m. Moving rate was measured to be less
than 5 cm/y.

Using the geo-electrical resistivity method, the permafrost thickness
was established for marine terraces and other terranes with different
degalaciation ages on Seymour and James Ross islands. These data,
combined with 14C isotope dating, enabled determination of the
permafrost development rates of 0.01 to 0.015 m/y for the marine
terraces on Seymour Island and 0.0018 to 0.0016 m/y for the marine
terraces on James Ross Island.

Thermo-registration devices, with sensors installed at different
depths, are continually monitoring the periglacial cryosphre, allowing
for the determination of the mean annual temperature gradient and the
daily temperature fluctuation (with data every 2 and 4 hours), for
each level, including air temperature. Three registering stations are
installed (with thermic sensors at specific ground levels) in a 10 m
deep drill at the highest meseta of Seymour Island, in a 2 m deep
drill at the coastal environment of James Ross Island, and, in the same
island, at a 1.8 m drill on the top of Rink Crags. Thermal
contraction parameters and heat flow are also established for
different ground levels on both islands.