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Appendix
1: NEW WORKING
GROUP
INVITATION
to join the new
IGCP Project
406Working Group
"THE EARLY AND MIDDLE PALAEOZOIC BASINS IN THE
CIRCUM-ARCTIC REGION:
PALAEOTECTONICS AND
PALAEOGEOGRAPHY"
Objectives
Half of the time planned for the
IGCP Project 406 has passed. At the Project 406 meetings
in Canada, USA, Estonia, Germany, Russia, and Poland new
and interesting data about Silurian and Devonian
stratigraphy, palaeontology, sedimentology, and
palaeoecology in the Circum-Arctic region have been
presented. We believe that in our future studies it will
be important to pay more attention to comparative
analysis of data from different parts of this region,
with the aim of reconstructing the palaeogeographical
situation, and to evaluating and improving palaeotectonic
reconstructions.
Program
We suggest focusing our studies in
the following directions:
1. Improvement of global correlations of Silurian and
Devonian sequences (based on detailed studies of some
selected intervals, particularly of the series
boundaries).
2. Comparative analysis of the evolution of the Silurian
and Devonian sedimentary basins in Canada, Greenland, NE
Europe (Timan-Pechora region) and the northern part of
Central Siberia. 3. Comparison of associations of
Silurian and Devonian faunas (brachiopods, ostracodes,
conodonts, vertebrates, etc.) from different palaeobasins
in the Circum-Arctic region.
4. Improvement
ofbiogeographical
subdivision of the studied regions.
5. Evaluation and improvement of palaeotectonic
reconstructions.
Main
problems to study
1.
Improvement of correlations
Main aim - recognition and correlation of the standard
series boundaries in the shelf sediments of Silurian and
Devonian basins in the Circum-Arctic region.
In the Silurian of particular interest are Llandovery and
Wenlock strata of Anticosti Island, Arctic Canada,
Timan-Pechora region, Novaya Zemlya, Severnaya Zemlya,
etc.
In the Devonian special attention should be paid to the
Lower Devonian, to the boundary between the Middle and
Upper Devonian, and to the Frasnian.
2.
Analysis of the evolution of palaeobasins
During recent years lithofacies and palaeogeographical
schemes have been composed for several stratigraphic
levels of the Silurian and Devonian palaeobasins in the
Baltic area, Timan-Pechora region, Polar Urals, Novaya
Zemlya, Severnaya Zemlya, Taimyr, and northern Central
Siberia. Also, sea-level curves have been compiled and
major evolutionary events recognized in these basins. The
palaeogeographical schemes allow a generalized and
detailed reconstruction of the evolution of these
basins.
Comparative analysis of the histories of different
palaeobasins allows us to work out an improved version of
event stratigraphy and sedimentological history for the
main Silurian and Devonian sequences of the Circum-Arctic
region.
The proposed studies include also detailed comparison of
the Silurian reefs in Alaska with those from Polar Urals,
and of Upper Devonian organic buildups in NW Canada with
those in the Timan-Pechora region.
3.
Biogeographical regions
Comparative analysis of faunal associations from
different regions will provide a basis for the evaluation
and improvement of existing ideas about the
distribution/configuration of the biogeographical
regions/faunal provinces.
4.
Evaluation and improvement of palaeotectonic
reconstructions
Published palaeotectonic reconstructions for separate
time intervals in the Silurian and Devonian are, in
general, well founded and differ only in details.
However, some details in such reconstructions, connected
with the location of Svalbard, Greenland, the Urals,
Novaya Zemlya, Severnaya Zemlya, Taimyr, Siberia, and
eastern parts of Baltica, are problematic in that they do
not agree with the latest palaeotectonical data.
Comparative analysis of sedimentological,
palaeontological, and palaeoecological data from the
Silurian and Devonian of the Arctic region of America and
Eurasia provides a basis for the recognition of
relationships between the palaeobasins on the shelf areas
and their connections with the palaeooceans.
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