P. Schmoldt, PhD - MTNet - DIAS

10. Data inversion
TM+TE
Depth (km)
TE-only
Depth (km)
S N
Campo de Montiel M.P.
Loranca Basin
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TM-only 0
Depth (km)
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pic020
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c
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b a
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0 16 32 48 64 80 96 112 118 144
Distance (km)
log10 (Wm)
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Fig. 10.4.: Comparison of results from isotropic 2D inversion for the Tajo Basin crust using a 100 Ωm halfspace as starting model and
data from both MT modes (TM+TE, top plot), only from the TE mode (TE-only, middle plot), and only from the TM mode (TM-only,
bottom plot). Location of PICASSO Phase I stations and the geological regions (based on the USGS EnVision map for Europe, Figure
9.1) are shown on the top of this figure; M.P: Manchega Plain
minimum-misfit models, but instead to contrast features of inversion models from the two
modes individually and simultaneously.
A common feature in all three inversion models is a near-surface conductive layer,
labelled ‘a’ in Figure 10.4. For the majority of the profile, layer ‘a’ is in a depth range
associated with the bottom of the sedimentary layer proposed by seismic studies (cf. Sec.
7.3.2). The increase in conductivity is likely to originate either from accumulation of fluid
or from an increase in salinity of the fluid at the bottom of the sedimentary layer. All three
inversion models indicated a vertical downward displacement of the conductive layer for
two regions located at the Manchega Plain – Loranca Basin boundary and at the northern
end of the profile (labelled ‘b’ in Figure 10.4).
Another feature evident in each of the three models is the conductive region at the
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a
e
f
b
b
b