| The results of our studies during Phase 1 showed that efficiency and accuracy
increases remarkably if a "multi-proxy approach"
is put into praxis. Such a multi-proxy approach demands a strong focus of
research activities that cross the borders of the above mentioned clusters
and the close co-operation of research groups of different disciplines.
As result of intensive discussions between the participating research groups,
research activities are carried out with a strong scientific focus on key
parameters that are required to reconstruct paleoceanographic circulation
patterns throughout the water column and the nature of the oceanic part
of the global carbon cycle. The research mainly concentrate on proxies that
provide information about palaeotemperature and palaeoproductivity in upper
water masses as well as intermediate and bottom water properties that are
important in relationship with diagenitic overprint such as bottom water
oxygen content and carbonate corrosiveness.
For a sound application of proxies it is essential to obtain
insight in the usability and limitations of them. To achieve this, information
on the basic processes that control the various proxies is required and
it is essential to test, adapt and further develop the proxies in analogue
as well as non-analogue situations. To achieve this, the studies focus on
periods and/or regions that are characterised by extreme climates and/or
environments and times of major abrupt change. Apart from developing and
testing the proxies in modern
environments, studies concentrate on certain time slices, Latest
Quaternary glacials and deglaciations, major
Neogene glaciation phases and the Late
Cretaceous oceanic anoxic event 3. Generally all projects plan
to work on several intervals. For a strong scientific focus the planned
research activities within the Graduate College will be carried out where
possible on similar sample sets. This results in a dense network between
the projects.
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Development, testing and validating proxies in modern environments
The planned studies in projects 7, 8, and 9, are dedicated to the separation of the in sediments reflected upper water bioproductivity signals with that of diagenetic overprint. This will be done by chemical and micropalaeontological proxies (see project descriptions). For a strong focus, experiments will be carried out during METEOR cruise M65-1 entitled “Palaeoclimatic history of the NW African continental shelf, benthic processes, biogeochemical cycles, preservation and diagenetic overprint of proxy signals” that is planned for June 2005 in the scope of RCOM.
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Late Quaternary glacial optima and deglaciation events
The Late Quaternary is characterised by a cyclic alternation of glacials and interglacials with rapid phases of deglaciation. It has been focus of intensive palaeoclimatic and palaeoceanographic studies and a wealth of information is available. The latter provides the required background information to test, validate and, if required, adapt the proxies studied in projects 1, 4, 7, 8, 9, and 10. Nevertheless, many questions about the interactions between the physical and biological oceanic processes with climate change remain to be solved.
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Major Neogene glaciation phases
Since the Cretaceous, the global ocean has evolved from a circum-tropical to a circum-Antarctic surface circulation and from a halothermal to a thermohaline deep-water circulation of today. The Neogene was a critical time of paleoceanographic reorganization during which the oceanic circulation became more similar to that of today. The opening and closing of gateways, the uplift of mountain ranges and the periodic and quasi-periodic oscillations in the Earth’s orbital parameters are thought to have influenced substantially e.g. the global ocean thermohaline circulation and geochemistry.
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Late Cretaceous oceanic anoxic event 3
The Late Cretaceous is associated with oceanic anoxic events (OAE’s), periods of elevated carbon burial in marine sediments known primarily from Tethyan Basins, the Atlantic and equatorial Pacific. To date there is an ongoing discussion if increased bioproductivity in surface water layers at times of deposition, stagnating vertical ocean circulation or a combination of both are causes of these events. |
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Research