P. Schmoldt, PhD - MTNet - DIAS

7.3. Tajo Basin and central Spain
Fig. 7.9.: a) Regional tectonic map of the Western Mediterranean with the yellow rectangle denoting the study area; AO: Atlantic
Ocean, BC: Betic Cordillera, MS: Mediterranean Sea. b) Simplified structural map of the study area with distinguished main tectonic
units, i.e. IM: Iberian Massif (dark grey), NB: Neogene Basins (white), EZ: External Zone (light grey), IZ: Internal Zone (orange).
c-j) Top view slices selected from the 3D resistivity model with the main resistive and conductive features identified, i.e. RIM:
Resistive Iberian Massif, RIZ: Resistive Internal Zones, CGU: Conductive Guadalquivir Basin, CG: Conductive Granada Basin, CGB:
Conductive Guadix-Baza Basin, CB1: Conductive Body 1, CB2: Conductive Body 2. Black dots in b-j) denote magnetotelluric
recording locations. From Rosell et al. [2010].
7.3. Tajo Basin and central Spain
The central region of Spain, comprising the Tajo Basin and its surrounding units, is described
here in more detail because parts of the PICASSO Phase I profile are located in,
and the focus of this study is on, this region. Thorough descriptions of evolution and
properties of the Tajo Basin are given, for example, in the work by Alonso-Zarza et al.
[2002] and in the respective chapters of the collection by Gibbons and Moreno [2002b].
In the following paragraphs, the relevant content of these references is summarised and
extended by findings of different authors covering certain aspects of the Tajo Basin geology;
furthermore, the results of geophysical investigations from a range of methods is
used to enhance knowledge about the geological setting.
7.3.1. Tectonic evolution and characteristics
The Tajo Basin (English: Tagus Basin) is bordered to the west by the Iberian Massif, to
the north by the Spanish Central System, to the east the Iberian Range, and in the south
by the Betics Chain and the Campo de Montiel (cf. Figs. 7.1, 7.12) all described in
more detail in the following paragraphs. The basin was formed during the Anisian age
(Middle Triassic) and subsequently widened until the Norian age (Late Triassic) due to
propagation of the Tethys Sea (which later became the Tethys Ocean) over the eastern
margin of the Iberian plate [Lopez-Gomez et al., 2002] (Fig. 7.13). Arising shallow
marine carbonates drowned the NW-SE trending Palaeozoic high that originally separated
the Tajo Basin from the Iberian Basin in the NW, resulting in a basin that is bounded to the
NW by the Iberian Massif, opened eastwards to the Tethys, and linked with the Betic basin
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