EUROPROBE News 9
CONTRASTING SIGNATURES OF THE LITHOSPHERE
Structure, composition and evolution of the continental
lithosphere-asthenosphere system
by Jörg Ansorge (Zürich), Hermann Zeyen (Uppsala) and Deep
Europe colleagues
Understanding the evolution of the continental lithosphere through
geologic time is one of the prime goals of the Earth Sciences. The joint efforts of
geoscientists during the recent decades have revealed the complexity of the processes that
have caused the present structure and state of the lithosphere-asthenosphere system.
Precise knowledge of structure and understanding of tectonic processes, however, are to a
large degree still limited to the crust. Plate tectonic and global geodynamic models
underline the relevance of upper mantle structure and dynamics for the evolution of the
overlying structure.
The study of the evolution of the continental lithosphere-asthenosphere
system involves such intriguing questions as:
How
do mountain ranges form and lose their roots?
Can
a "normal cooling" history of crust, lithospheric mantle and possibly
tectosphere be defined and if so, what are its characteristics?
What
are the sources of thermo-mechanical events such as the rise of mantle plumes or the
initiation of rifting, subduction and back-arc spreading, and what are their effects on
continental lithosphere in different evolutionary stages?
Are
the geodynamic processes acting today similar to those that have acted during the Archaean
and Early Proterozoic?
How
does the continental lithosphere grow and change its characteristics through time?
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