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Mid-Term Conference - Potsdam, Germany
Mid-Term Conference - Potsdam, Germany
9-12 January 2007 GeoForschungsZentrum Potsdam
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A new crustal model as input for the European strength map
Tectonic studies made in intraplate Europe have shown that
this area is more 
active than would be expected from its location far away
from plate boundaries. 
Intraplate Europe is characterized by horizontal and
vertical motions with 
deformation rates of the order of 1-2 mm/yr and by diffuse
seismicity (Nocquet 
and Calais, 2003, Tesauro et al., 2005). The first strength
map (Cloetingh et al., 
2005) has lead to a significant understanding of the
dynamics of intra-
lithospheric deformation processes. The results have
demonstrated that the 
European lithosphere is characterized by large spatial
mechanical strength 
variations, with a pronounced contrast between the strong
lithosphere of the 
East-European Platform (EEP) east of the Tesseyre-Tornquist
Zone (TTZ) and 
the relatively weak lithosphere of Western Europe. 
In order to improve the previous results and to extend the
calculations to the southern and western plate boundaries of
Eurasia, we are 
going to construct a new crustal model, which is a part of a
lithosphere model. As the first result, we demonstrate the
new Moho map of 
Europe. The Moho depth variations are reconstructed by
merging the most 
recent maps compiled for the European regions (e.g. Ziegler
and Dèzes, 2002, 
Kozlovskaja et al, 2003) and by ourselves using published
interpretations of 
seismic profiles (e.g. in the Vøring and Lofoten basins). 
Strong differences in the crustal structure are found
between the areas east 
and west of the TTZ, respectively. The eastern region is
mostly characterized by 
thick crust, e.g. over the Baltica region (~42-44 km) with a
maximum of over 60 
km in the Baltic Shield. By contrast, crustal structure is
more heterogeneous to 
the west from TTZ, being characterized by Variscan crust
with an average 
thickness of 30-35 km, orogens (e.g. the Alps and the
Pyrenees), where the 
crustal thickness is increased up to 45-50 km, and locally
by strong extensional 
deformation, which resulted in a very thin crust in the
Pannonian Basin (~25 
km) and in the Tyrrhenian Sea (~10 km). Concerning the
oceanic domain, the 
crustal thickness is generally decreased towards the ridge
(up to 10 km in the 
most western part), with local maxima up to 20-25 km (e.g.
in the Vøring and 
Lofoten basins) and up to 35-40 km beneath the islands (e.g.
Iceland and 
Faeroe islands), on account of mantle underplating.
We calculated gravity effect of the Moho variations and
density variations 
within the crust (Kaban, 2001) and removed it from the
observed gravity field, 
which gives the residual mantle anomalies (Fig. 4). Since
the upper mantle 
density is supposed to be constant in the reference model
(3.35 g/cm3), the 
residual anomalies chiefly reflect the effect of mantle
density variations (Kaban, 
2001, 2002, Kaban et al., 2004). The mantle anomalies are
clearly separated 
into two components possibly accounting for the effects of
different factors: 
(1) A long-wavelength component reflects large-scale structural 
heterogeneities of the Eurasia lithosphere, supposedly
related to its thermal 
regime. In the study area the TTZ divides EEP, which is
characterized by 
predominantly positive anomalies from Western Europe with
mostly negative 
mantle anomalies.
(2) A regional relatively short-wavelength component (L
<2000 km) correlates 
with specific tectonic structures. A chain of negative
mantle anomalies (~ -100 
mGal) is found west of the TTZ (Pannonian basin; Rhine
graben and Massif 
Central). A very distinctive positive anomaly (>100 mGal) 
is located over the 
Carpathians and the Adriatic Sea, supporting the idea about
strong lithospheric 
The results of deep seismic reflection and refraction and/or
receiver function 
studies will be used to define the depth of the crustal
interfaces and P-wave 
velocity distribution in order to complete the new crustal
model. Furthermore, in 
the next stage, seismic tomography data will be used to get
the location of the 
lithosphere-astenosphere boundary and calculate the
temperature distribution. 
These results, jointly with the new crustal model, will
allow us to re-calculate a 
strength state of the European lithosphere and to construct
a new density 
Id: 25
Place: GeoForschungsZentrum Potsdam
14473 Potsdam
Room: Building H, auditorium and seminar rooms
Starting date:
12-Jan-2007   11:15
Duration: 05'
Primary Authors: Ms. TESAURO, Magdala (Vrije Universiteit)
Co-Authors: Dr. KABAN, Mikhail (GFZ)
Prof. CLOETINGH, Sierd (Vrije Universiteit)
Presenters: Ms. TESAURO, Magdala
Material: slides Slides

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