EUROPROBE News 9
TIMPEBAR: Basement Control on Basin Evolution
by David G. Gee (Uppsala), Peter A. Ziegler (Basel) and
Timpebar colleagues
TIMPEBAR
focuses on the evolution of Europe's northeastern Arctic shelf, comprising the Pechora,
Eastern Barents Sea and North Kara Sea basins and their fringing terranes, which outcrop
in the Timan Range (northeastern margin of the East-European Craton), Polar Urals, Novaya
Zemlya, Taimyr and Severnaya Zemlya. Research on these areas is being integrated with
on-going studies of the Western Barents Sea and the Svalbard archipelago.
The
shallower Pechora Basin and the ultradeep Southeastern Barents Sea Basin host two of
Europe's most important hydrocarbon provinces. These basins, together with the still
little explored Northeast Barents Sea Basin, are located in the foreland of the northern
parts of the Uralide Orogen. Their evolution and the age of their underlying crust differs
significantly from that of the central and southern Urals foreland basins. The TIMPEBAR
project will contribute to the resource assessment of this vast frontier area.
In
the Pechora Basin, many drillholes penetrate its entire sedimentary fill and bottom in
basement; Neoproterozoic and Baikalian-age rift-related igneous rocks and island-arc
volcanics have been reported. Available geophysical and well data provide a substantial
base for analysing the age, composition and structure of the basement. In the Barents Sea,
no wells have reached basement and its age has to be inferred from outcrops on the
mainland and high Arctic islands. Deep seismic profiles crossing the Pechora and Eastern
Barents Sea basins provide evidence of a crustal and upper mantle structure that differs
greatly from that of the Uralide foreland to the south. A vast amount of industrial
reflection-seismic profiles, in combination with results of deep wells, provide an
essential data base for analysing and modelling the architecture and evolution of the
Pechora and Eastern Barents Sea basins.
Analysis
of existing data provides the foundation for multidisciplinary investigations, including:
Determination
of the age and composition of the Pechora basement by geochronological and geochemical
analyses of drill-cores from folded Baikalian age (?) pre-Ordovician successions and their
associated igneous and metamorphic rocks.
Complementary
studies of the Polar Urals, Novaya Zemlya and Taimyr, where Baikalian-age terranes occur,
locally with ophiolites and high P/T metamorphic rocks.
Interpretation
of the crustal structure of the Pechora and Eastern Barents Sea basins from wide angle and
near vertical seismic profiles, integrated with potential field data.
Analysis
of the structure, stratigraphy, sedimentology, metamorphism and igneous activity of the
Timan Range, providing control on the southwestern margin of the Pechora Basin.
Integrated
analysis of Barentsia, underlying the northwestern parts of the Barents shelf.
Quantitative
modelling of the evolution and thermal regime of the Pechora and Eastern Barents Sea
basins; comparison with the central and southern Uralide foredeep basins.
Acquisition
of selected new regional deep seismic profiles both on- and off-shore (CMP and wide-angle,
comparable to URSEIS), to obtain an image of the crust and upper mantle, permitting
analysis of their response to a sequence of contractional and extensional events.
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