|
| |
EUROPROBE PROJECTS
|
|
SVEKALAPKO:
Evolution of
Palaeoproterozoic and Archaean Lithosphere |
One of
the best places on Earth for studying the thermal and mechanical processes controlling the
evolution of ancient lithosphere is the Fennoscandian Shield. This
well-exposed, composite craton, cored by the Late Archaean granite-greenstone Karelian
belt, and flanked to the northeast and southwest by Palaeoproterozoic orogens, is ideal
terrain for testing plate tectonic theory and seeking to understand the contrasted
signatures of Archaean and Proterozoic lithosphere.
A
considerable geological, geochemical and geophysical data base provides the foundation for
focused new EUROPROBE investigations. Deep seismic refraction profiles have defined the
velocity structure of the shield; shallow CMP reflection profiles in Russia give unique
insight into upper crustal structure. Deep and superdeep drillholes (including Kola)
provide exceptional opportunities for calibrating further geophysical data.The
Fennoscandian Shield is a key element in the reconstruction of the Laurussian
mega-continent. EUROPROBE studies will promote integration with Canadian Lithoprobe
geoscience.
EUROPROBE’S multidisciplinary investigation of the Fennoscandian Shield SVEKALAPKO:
(SVEcofennian-KArelia-LAPland-KOla)
focuses on the following key issues:
Establishing
the character of the deep lithosphere (lower crust and upper mantle) and its relationship
to the asthenosphere below the different parts (Lapland-Kola, Karelia and Svecofennia) of
the Fennoscandian Shield. The latter provides unusually favourable bedrock conditions for
major geophysical experiments aimed at defining lithosphere-asthenosphere relationships,
particularly electromagnetic probing and deep tomography studies. An important target is
the deep structure of the highly anomalous (c. 60 km thick) juvenile Svecofennian crust,
where correlation with gravity data and topographic relief are lacking.
Defining
the crustal evolution across the Shield to establish the timing of formation of the
different major structures and their relationship to the underlying deeper lithosphere;
this will provide insight into ore genesis and contribute to further exploration efforts.
Particular interest concerns:
The
Archaean evolution of the Karelian terrane and the extent to which it has been reworked in
post-Archaean time.
The
Proterozoic suturing, with the local preservation of ophiolites and prominent boundaries
between reworked Archaean and juvenile Proterozoic rocks.
The
evidence for subduction-related magmatism and development of Proterozoic fore-and back-arc
basins.
The
analysis of crustal and upper mantle xenoliths.
The
effects of Palaeozoic (Devonian), potentially plume-related magmatism on lithospheric
structure of the Kola-White Sea areas.
Visit
the SVEKALAPKO homepage
Get
the SVEKALAPKO text and figures out of the EUROPROBE 1996 publication by clicking on the
corresponding text.
Click on the figure and see the image enlarged
PDF-viewers can be obtained through the net for different
operating systems.
For more information please contact the project
leaders:
Prof. Sven-Erik Hjelt
Dept. of Geophysics
University of Oulu
POB 333
FIN-90571 OULU
FINLAND
Tel: +358-8/553 14 01
Fax: +358-8/553 14 14
E-mail: seh@babel.oulu.fi |
Dr. Stephen Daly
Dept. of Geology
University College
Belfield
DUBLIN 4
IRELAND
Tel: +353-1/706 23 27, /706 23 31
Fax: +353-1/283 77 33
E-mail: Stephen.Daly@ucd.ie |
|
