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IGCP 503: Background and aims
Arguably the most sustained rise in
marine biodiversity
took place during the Ordovician, and the second largest mass
extinction
event took place close to the end of that Period, coincident with an
episode
of major climate fluctuation. The results of the very successful IGCP
project
n° 410 "The Great Ordovician Biodiversification Event" not only
included
the development of an improved globally-integrated biozonation for
graptolites,
conodonts and chitinozoans, but also generated biodiversity curves that
have been constructed for all Ordovician fossil groups.
Following the work of the numerous
regional teams
and of the clade teams, that were established for each fossil group in
IGCP project n° 410, we propose a new successor project in order to
develop a better understanding of the environmental changes that
influenced
the biodiversity trends in the Ordovician and Early Silurian. In our
project,
the major objective is thus to attempt to find the possible physical
and/or
chemical causes (e.g., related to changes in climate, sea level,
volcanism,
plate movements, extraterrestrial influences, etc.) of the Ordovician
biodiversification,
the end-Ordovician extinction, and the Silurian radiation.
Work on understanding the patterns of
biodiversity
change at a range of taxonomic, spatial and temporal scales will
continue
through the duration of the project but our objectives in terms of
understanding
the environmental parameters within which these changes took place will
be addressed in successive step over the five years 2004-2008:
- the first year will focus on ocean
and climate modelling,
and the development of stable C-, O-, and Sr isotopes in the
Lower
Palaeozoic;
- the second year will focus on the evolutionary
palaeoecology
of the Early Palaeozoic;
- in the third year, we concentrate on changing
palaeogeographical
patterns;
- in the fourth year, we compile all
information on Early
Palaeozoic events and stratigraphy;
- in the last year of our project, all
information collected
from the different regional teams should allow us to reconstruct Early
Palaeozoic sea-level changes.
Over the five years that the project will run
(2004-2008) we will organise the following major meetings in successive
steps from 2004 to 2008:
- September 2004, official
opening
meeting at
Erlangen, Germany: ocean and climate modelling, and the development of
stable C- and O-isotopes; field meeting S-Sweden
(Fågelsång,
Öland, Gotland); proceedings
volume available as pdf files (pictures from the meeting and field trip)
- 2005, meeting at Milwaukee,
Wisconsin, USA:
evolutionary palaeoecology, onshore-offshore transects;
- 2006, meeting at Glasgow,
Scotland, UK: changing
palaeogeographical and palaeobiogeographical patterns;
- 2007,
10th International Symposium of the Ordovician System, 3rd International Symposium of the Silurian System, in conjunction with the IGCP 503 meeting at Nanjing: geological events and the stratigraphical
framework;
- 2008, closing meeting at
Lille,
France: reconstruction
of sea-level fluctuations and final synthesis.
The new project will be developed in
collaboration
with the Subcommission on Ordovician Stratigraphy (SOS) and with the
Subcommission
on Silurian Stratigraphy (SSS). The understanding of the changes of the
marine diversity in the Ordovician and Silurian (including the oldest
and
second largest of the "Big Five" Mass Extinctions) at the global level
should provide us a better understanding of the evolution of life on
our
planet in relation to palaeogeographical and palaeoclimatical
changes.
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