60
fine-grained sediments due to their higher surface area to volume ratio and their
compositional characteristics. In order to compensate for granulometric effects,
results were normalized to aluminum concentrations (Ackermann 1980; Schropp
et al. 1990; Cundy and Croudace 1996; Covelli and Fontolan 1997; Mil-Homens
et al. 2006). This element shows a positive correlation with metals in pre-industrial
materials from this area (Cearreta et al. 2002, 2013).
2.5.4 Aerial Photography
Geological determination of the recent environmental evolution of the studied areas
can be supported by modern and historical aerial photography that procure approximate dates to the interpreted natural and anthropogenic processes.
Aerial photography presents a graphical proof of the agricultural occupation and
later environmental regeneration process in northern Spain. In this sense, photographs from the 1950s commonly show tidal channels invading formerly reclaimed
lands, providing evidence of the abandonment of agricultural activities around the
mid-20th century in most locations of northern Spain (Fig. 2.8).
Fig. 2.8 Agricultural fingerprints in historical aerial photography (1957: left side) compared to a
modern photograph (2009: right side) of the nowadays regenerated Busturia salt marsh, Urdaibai
estuary (Modified from Cearreta et al. 2013)
Fig. 2.7 Pb/Al profile for
age determination of
sediments from the
Baraizpe salt marsh,
Urdaibai estuary (Modified
from Cearreta et al. 2013)
A. García-Artola et al.
fine-grained sediments due to their higher surface area to volume ratio and their
compositional characteristics. In order to compensate for granulometric effects,
results were normalized to aluminum concentrations (Ackermann 1980; Schropp
et al. 1990; Cundy and Croudace 1996; Covelli and Fontolan 1997; Mil-Homens
et al. 2006). This element shows a positive correlation with metals in pre-industrial
materials from this area (Cearreta et al. 2002, 2013).
2.5.4 Aerial Photography
Geological determination of the recent environmental evolution of the studied areas
can be supported by modern and historical aerial photography that procure approximate dates to the interpreted natural and anthropogenic processes.
Aerial photography presents a graphical proof of the agricultural occupation and
later environmental regeneration process in northern Spain. In this sense, photographs from the 1950s commonly show tidal channels invading formerly reclaimed
lands, providing evidence of the abandonment of agricultural activities around the
mid-20th century in most locations of northern Spain (Fig. 2.8).
Fig. 2.8 Agricultural fingerprints in historical aerial photography (1957: left side) compared to a
modern photograph (2009: right side) of the nowadays regenerated Busturia salt marsh, Urdaibai
estuary (Modified from Cearreta et al. 2013)
Fig. 2.7 Pb/Al profile for
age determination of
sediments from the
Baraizpe salt marsh,
Urdaibai estuary (Modified
from Cearreta et al. 2013)
A. García-Artola et al.