Iraqi Kurdistan All in the Timing

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continue to move endlessly around
Antarctica; as this text is further drafted
(28 February), we are experiencing a fullblown
gale with driving snow off Cape
Adare created by the latest of these lows.
Once again, no landings are possible.
More detail on the geology of the Ross
Sea may be found in the memoir and
1:250,000 map that covers the Southern
Ross Sea, for which ‘Mo’ Turnbull is a
senior author. It is available online at
http://www.gns.cri.nz/Home/Products/
Maps with the title Geology of Southern
Victoria Land, Antarctica.
Neogene Volcanoes
On our trip most planned landings and
near-shore transits were possible, though
sometimes only after several attempts,
with the cloud generally high enough to
savour the ‘winter wonderland’ scenery.
Especially eye-catching was the scale of
the Neogene volcanoes in and around
Ross Island. The most significant was
Mount Erebus (3,794m), the world’s
most southerly active volcano. It is
distinguished by its permanent, often
boiling lava lake and visually, from afar,
by a white plume associated with near
continuous Strombolian eruptions. Major
eruptions, however, are currently rare,
with perhaps the last one observed by Sir
James Clark Ross in 1841 during his first
expedition to Antarctica.
Equally spectacular were Mount
Terror and Mount Bird, the latter
being a shield volcano smothered with
ground-hugging, Christmas-cake-like
layers of ice. All three volcanoes carry
Agnes Breniere /Heritage Expeditions
An unusually vigorous eruption from Mount Erebus viewed while at anchor off McMurdo Station at
close to midnight.
satellite ash cones and lava domes.
Landings on Ross Island were made at
the USA’s McMurdo Station and Captain
Scott’s Discovery Expedition hut on Cape
Evans. McMurdo provides the most
southerly possible rock landing in the
Ross Sea. Geologically it is located at the
southern end of a narrow line of young
cones known as the Hut Point Peninsula.
New Zealand’s Scott Base is nearby, but its
position on the other side of the peninsula
means that it is normally ice bound.
Observation Hill, just south of
McMurdo Station, is a prominent cone
built of flow banded, phonolite lavas,
obsidian and loose scoria. Its 226m-high
summit would have been the perfect
vantage point for early polar explorers to
have scouted out routes up the glaciers
running from the Polar Plateau into the
Ross Sea.
Important Geological Vista
Even from ship level and with the
naked eye, the westward rising
glaciers were clearly visible from Ross
Island, more than 50 km away across
McMurdo Sound. Equally visible were
the horizontal beds of the Beacon
Supergroup rising steeply above the
more subdued coastal topography of
the Skelton Group metamorphics. Also
surprisingly conspicuous within the
Beacon Supergroup were the hundreds of
metres of thick, black dolerite sills of the
Ferrar Dolerite. This has to be one of the
greatest geological vistas possible on this
planet, particularly given the importance
of this mountain range in understanding
the assembly of Gondwana, and its role
in providing access to the south for
South Pole expeditions.
Often visible in the mountains are
Samuel Blanc/Heritage Expeditions
Ferrar Dolerite
Beacon Supergroup
Skelton Group
The Transantarctic Mountains viewed
from McMurdo Station. The stamp shown
above was issued by New Zealand in
1984 as part of a set depicting Antarctic
research. These are black Ferrar Dolerite
outcrops in the stamp’s background
mountain, and the geologist is holding an
artist’s rendition of a Glossopteris frond.
80 GEOExPro November 2015