P. Schmoldt, PhD - MTNet - DIAS

7. Geology of the Iberian Peninsula
Fig. 7.28.: Rheological profiles of the Tajo Basin (northern part on the left-hand and southern part on the right-hand side) in terms of
tension and compression at a strain rate of 10 −15 s −1 for rheological parameters given in Table 7.4. Outer black lines bind differential
stress estimated for dry rock composition; inner black lines denote stress for wet rock composition of the upper crust (quartzite or
granite) and lithospheric-mantle (peridotite). Geometric symbols mark the base of competent layers for the upper, middle, and lower
crust as well as the lithospheric-mantle, i.e. : wet quartzite, : quartzdiorite, : wet peridotite, ⋄: dry peridotite; note that only wet
rock data shown for the upper crust, from Tejero and Ruiz [2002].
Rheological property
Thickness (km)
Central Spain Central Betic Cordillera
Elastic thickness Te 20 - 25 15 - 20
Mechanical strong upper crust (MSUC) ∼18 ∼15
Mechanical strong lower crust (MSLC) 6 - 10 ∼11
Mechanical strong upper mantle (MSL) 8 - 12 ∼6
Tab. 7.5.: Rheological properties of the regions relevant for the PICASSO Phase I investigation of the Iberian subsurface; the values
are visually derived from the thermal and rheological European lithosphere model by Tesauro et al. [2009a, Figs. 3, 4].
ties, with characteristic values of the radiogenic heat production for each crustal layer are
presented by Tesauro et al. [2009a] and Tesauro et al. [2009b]. The authors use the seismic
tomography model by Koulakov et al. [2009], which incorporates teleseismic events
as well as travel time data, with a correction of the travel times based on the EuCrust-
07 model [Tesauro et al., 2008]. For the region coinciding with the PICASSO Phase I
profile, the authors derive a depth between 120 km and 130 km for the 1200°C isotherm,
indicating the lithosphere–asthenosphere transition. In their model, Tesauro et al. [2009a]
and Tesauro et al. [2009b] further infer temperatures of approximately 880 – 980°C and
1120°C at 60 km and 100 km depth, respectively. From their thermal model, in combination
with the EuCrust-07 model [Tesauro et al., 2008], the authors derive rheological
settings for the European lithosphere with properties of the region most relevant for the PI-
CASSO Phase I investigation summarised in Table 7.5. However, results by Tesauro et al.
[2009a] and Tesauro et al. [2009b] are associated with a higher degree of uncertainty since
they are based on seismic data, which have lower resolution in Iberia; aggravated by the
fact that the model is of European scale, hence down-weighting local effects. The lower
resolution in Iberia is therein due to its location on the edge of the European continent as
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