International Polar Year 2007–2008 - WMO

– the Fram Strait, Davis Strait/Baffin Bay with the
Canadian archipelago as well as the Bering Strait – were
investigated by a wide spectrum of geophysical and
geological approaches to understand the timing and
palaeoclimatic consequences of water mass exchange
(e.g. Jakobsson et al., 2007) (Fig. 2.8-3). Recent work
indicates that early Barents Shelf glaciation correlates
with the initial deep water opening of the Fram Strait
in the middle Miocene at about 15-14 million years
ago (Knies and Gaina, 2008) (Fig. 2.8-4). A particular
highlight was the multi-national, multi-expedition
effort over several IPY seasons to obtain geophysical
and geological data from the Barents Sea shelf,
Svalbard and the adjacent Atlantic oceanic crust
from the lithospheric mantle to shallow sediments
(e.g. Wilde-Piórko et al., 2009) in order to improve
understanding of the geodynamic, tectonic and
sedimentary processes leading to and accompanying
the initiation of major Arctic glaciation phases.
Antarctic studies
In the three Antarctic field seasons 2006/2007,
2007/2008 and 2008/2009, geophysical and
Fig. 2.8-4. Reconstructed
palaeobathymetry and
palaeotopography at about
14 million years ago with
suggested path for icebergs
(yellow arrows) and the
extent of the northern
Barents Sea ice sheet (after
Knies and Gaina, 2008).
bathymetric surveying as well as geological and
biological sampling have been conducted in critical
regions of the Southern Ocean that formed since
the break-up of Gondwana (Fig. 2.8-5). A thorough
revision of the break-up processes was performed
in parallel with acquisition of new data, compilation
and integration of existing data sets. The early stages
of development of the Drake Passage/Scotia Sea
gateway (e.g. Livermore et al., 2007; Maldonado et
al., 2007) are now better constrained by studies of
the tectonic and sedimentary evolution of the basins
and the origin of bathymetric highs, the structure and
history of relevant plate boundaries, and deformation
of neighbouring land areas. In a multi-institutional
effort, the areas of the southern to central Scotia Sea
and northernmost Antarctic Peninsula have been
surveyed and sampled thoroughly by a number of
Spanish, Italian, U.K., Polish, Argentine, Chilean and
U.S. led ship- and land-based expeditions during the
IPY which will help solve the puzzle of plate kinematics
and sedimentary basin evolution (e.g. Bohoyo et al.,
2007; Maestro et al., 2008; Alfaro et al., 2010). From
geophysical data of the Tasmanian Gateway, the
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