ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

Land. Abandoned penguin rookeries are common landscape
features related to biological activity all over the Victoria
Land coast. Ornithogenic soils from abandoned penguin
nesting sites supply several radiocarbon dates that document
the penguin re-colonization of the Antarctic continent.
The oldest date was obtained at Cape Hickey
(northern side of Mawson Glacier basin) where penguins
nested since 12 ka BP. Furthermore, several localities
between Ross Island and Terra Nova bay were completely
deglaciated and occupied by Adelie penguin rookeries since
10 ka. Coastal deglaciation was completely accomplished
about 8-9 ka BP.
Deglaciation was followed by the uplift of the coastal belt
and by the retreat of local ice shelves that reached minimal
position about 7-6 ka BP. Sets of Holocene raised beaches,
marine pavements and marine terraces are widespread coastal
features. 14C dates from marine organisms and ornithogenic
soils allowed the reconstruction of curves of emersion
for different sectors of the Victoria Land coast. Evidence
of Holocene glacier variations (i.e, «Medieval warm
period» retreat and Little Ice Age advance) complete the
picture of the geomorphological evolution of the coastal
Victoria land areas.
CARLO BARONI 1, ALESSANDRO BIASINI 2,
ALDINO BONDESAN 3, MIRCO MENEGHEL 3,
GIUSEPPE OROMBELLI 4 & M.CRISTINA SALVATORE 2
The geomorphological map of the Terra Nova Bay Area,
Victoria Land, Antarctica
1Dipartimento di Scienze della Terra, Universita di Pisa,
via S. Maria 53,1-56100 Pisa, Italy
2 Pnra-Unita Operativa Gla 23 c/o Dipartimento di Scienze
della Terra, p.le A. Moro 2,1-00185 Roma, Italy
3 Dipartimento di Geografia, Universita di Padova,
via del Santo 26, 1-35123 Padova, Italy
4 Dipartimento di Scienze dell'Ambiente e del Territorio, Universita di
Milano, via Emanueli 15,1-20126 Milano, Italy
The mapped area is located in Terra Nova Bay, to the
south of the Italian Station. It extends from the Nansen Ice
Sheet (including Cape Confusion, Vegetation Island and
Inexpressible Island) to the southern side of the Campbell
Glacier. The eastern limit is the coast of Ross Sea, here forming
the Terra Nova Bay; the western one is the deep
trough of the Browning Pass. The .morphology is mainly
moulded by glaciers, and rounded summits together with
smoothed slopes are present. Glacial deposits are widespread.
Connected with the Holocenic deglaciation is the
uprise of the coastal area with a rate ranging from 2 to 5
mm per year in the last 5000 years.
In the mapped area five physiographic units can be distinguished.
Inexpressible Island - The island is about 13 km long in
the NNW-SSE direction, and have a triangular shape. Its
western portion have an higher altitude and rocks are largely
outcropping in rounded summits. Polygons develop
where a debris cover is present. A scarp divides this higher
portion from the eastern lower part of the island, where a
large cover of glacial drift is present. On the drift many
periglacial features develop (terraces, sorted and non-sorted
polygons, ice cored dirt cones). On the south a flat
surface has been interpreted as the bottom of a previous
cove or lagoon, now raised above the sea level. Along the
present coast, around the raised sea floor and on the side
to Hell's Gate raised beaches have been recognized by
many researchers.
Hell's Gate Ice Shelf - The Hell's Gate Ice Shelf extends
in the central part of the map, flowing from northwest
to south-east into the Ross Sea. A double morainic
ridge to the east and two alignments of ice-cored dirt cones
to the west are present on its surface. Other complex
moraines outcrop near Cape Confusion and to the east of
Vegetation Island. The ice shelf is characterized by a
strong uprising towards the surface, due to intense surficial
ablation by the katabatic winds descending from the
Antarctic Plateau; so marine ice outcrops in the coastal
belt of the shelf.
Vegetation Island - Vegetation Island is a rock bluff (a
real nunatak) long about 4.5 km in NNE-SSW direction,
emerging between the ice flows of the Priestley and other
local glaciers. Its western slope is vertical, the eastern side
is something gentler. A deposit of supraglacial debris rests
on the lee side of the glacial flow.
Cape Russel - The promontory of Cape Russel is a long
narrow strip of ice-free rock limited on the western side by
snowfields and a local glacier and on the eastern side by
the sea. Here rocks are almost free from debris cover. In
the northern part they form a smooth surface, with some
rounded summit. In the southern portion an almost flat
horizontal surface can be interpreted as a terrace (probably
a raised abrasion platform). On the western side, close to
the limit of the Hell's Gate Ice Shelf, raised beaches reach
an altitude of about 20 m.
Northern Foothills - The upper portion of the Northern
Foothills is largely covered by local glaciers and snowfields.
Scattered rock outcrops form a smooth surface
with rounded knobs. Its surface is strongly weathered,
with varnish and tafoni. Where a debris cover is present,
polygons and gelifluction terraces develope. The portion
closer to the sea is more ice free and debris cover is more
abundant. As a whole, the surface can be considered a
plane gently sloping toward the sea. Along the coast a high
cliff has been cut by marine action. To the west, the
Northern Foothills are limited by a steep slope facing the
Browning Pass.
The map has been drawn to give the many researchers
carrying out investigations in the field near the Italian Station
an easy-to-read tool to frame their observations in a
geographic and geomorphological context. The base of the
map is a georeferenced satellite image processed by M.
Frezzotti in the Enea laboratory. On it contour lines have
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