Dear all

In the Frame of the Annual Meeting of the Swiss Academy of Natural
Sciences (SANW) 2002 entitled "Science and the Magic Mountain"

Two special Earth Science Workshops on the Evolution of the Alps (see
description below)
19th-20th September 2002, Davos (Switzerland)

This workshop will be complemented by two excursions led by D.
Bernoulli, G. Manatschal and O. Müntener.

All informations (registration, program, virtual excursions...) can
be found at the following address:
http://www.unibas.ch/earth/tecto/davos2002

Hoping to see you soon

Daniel Bernoulli
Romain Bousquet



A- Erosion and orogeny

Convenors: D. Bernoulli, S. Schmid (Basel) and H. Weissert (Zürich)
Keynote speakers: N. Hovius (Cambridge) and F. Schlunegger (Zürich)

It is now generally accepted that surface erosion influences the
nature and evolution of lithospheric deformation during compressional
orogenesis by changing the topography and hence the thickness of the
deforming orogen. This, in turn, results in a modification of the
relative importance of the two driving forces of orogeny:
gravitational versus "tectonic" force. While efficient erosion tends
to localize deformation within a relatively narrow belt, a decrease
in erosional activity may cause deformation to propagate towards more
distal sites.
Erosion rates are well known to be controlled by rock type, climate
(through discharge in rivers and the dependency of hillslope
diffusivity on moisture content) and morphometric parameters. Any
change in these variables is expected to modify the evolution of
topography and the flux of mass leaving the orogen. In particular, a
decrease in the mean precipitation as may occur during a transition
from a humid to a relatively dry climate will generally decrease the
erosional efficiency and the sediment mass flux. This will tend to
increase the mean topography in the presence of surface uplift. A
similar effect is expected to be caused by decreasing the erodibility
of rocks exposed on the surface through continuous exhumation of
rocks derived from progressively deeper crustal levels. Thus, one can
propose a possible link between changes in erosional efficiency and
changes in the geometry of orogens and thus on their evolution.
This workshop intends to motivate researchers to present the results
of their research with respect to possible feedback mechanisms
between (paleo)climate, erosional processes, landform development,
and tectonics of mountain belts.We also intend to learn more about
possible controls of climate, tectonics, bedrock lithologies and
human activities on sediment yields.


B- Birth and Early evolution of Alpine Ocean Basins

Convenors: D. Bernoulli, S. Schmid (Basel) and G. Manatschal (Strasbourg)
Keynote speakers: Y. Lagabrielle (Brest) E. Rampone (Genova) and O.
Müntener (Neuchâtel)


The Alps are an excellent natural laboratory for studying the
earliest history of ocean basins. Along present-day continental
margins, the geological record of continental break-up and incipient
sea-floor spreading is usually buried by thick sequences of post-rift
sediments and can only be investigated by reflection seismic
profiling and one-dimensional deep sea drilling cores. In the Alps,
however, the original architecture of the distal continental margin
and of the ocean-continent transition can often be reconstructed with
confidence; in particular, the tectonic structures and associated
fault rocks can be observed directly.
The synthesis of both approaches, i.e. of deep-sea drilling results
and seismic reflection profiling in present-day ocean-continent
transitions with the direct observation of tectonic structures, fault
rocks and syn- and post-rift sediments, turned out to be extremely
fruitful. It led to the formulation of new models regarding the
transient phase from rifting to spreading in the type-area of the
"Steinmann Trinity".



The meeting in Davos will give the opportunity to discuss fundamental
processes associated with early ocean evolution. These are, for
example: mantle evolution and exhumation, relationships between
extensional tectonics and magmatism or sedimentation, and the
significance of low-angle detachments. Three days of excursion will
give an opportunity to discuss different models in the field.
We would like to motivate our colleagues to present the results of
their research in Alpine or present-day oceanic settings and to
discuss them with us in a beautiful field area.



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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dr. Romain Bousquet
Earth Sciences Department
University of Basel
Bernoullistr. 30
CH-4056 Basel - Switzerland
Ph: (41) 61 267 3632 / fax: (41) 61 267 2813
http://www.unibas.ch/earth/tecto/
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