Biscay (De Mol et al. 2011; Sa ´nchez et al. 2014) and expanded with emphasis on
DIC concentrations (Fl€ ogel et al. 2014). There are some reports about CWCs
tolerating different seawater density values in submarine canyons of the Celtic
Margin in the Bay of Biscay (Huvenne et al. 2011) and especially in the Mediterranean Sea (Freiwald et al. 2009). White and Dorschel (2010) claim that the
described sigma-theta density envelope generally corresponds to a sharp pycnocline
that may be helpful in concentrating food particles.
11.1.2 Geological Setting
The Cantabrian Margin bounds the Bay of Biscay in the south characterized by a
narrow shelf in contrast to the Armorican and Celtic Margins in the NE. This
narrow shelf descends rapidly to the deeper parts of the bay exhibiting a continental
slope of variable morphologies (Ercilla et al. 2008). Numerous spurs and canyons
intersect the Cantabrian margin in a downslope direction (Cremer 1981; Kenyon
1987) similar to the Armorican and Celtic Margins (De Mol et al. 2011). The Bay of
Biscay originated from sea floor spreading that began in the Late Permian/Early
Triassic, characterized by normal faults, asymmetric basins, and low angle detachments (Manatschal 2004) which continued until the Lower Cretaceous. During the
Upper Cretaceous a passive continental margin formed (Boillot et al. 1979;
Dere ´gnaucourt and Boillot 1982). The narrow shelf is the result of a complex
tectonic history which culminated in the Oligocene (Tertiary) with a partial closure
of the Bay of Biscay and the intense compression, shortening, and lateral shearing
of the Cantabrian Margin (Thinon et al. 2001; Gallastegui et al. 2002) and the
uplift of the Cantabrian mountains (Pe ´rez-Estau ´n et al. 1995; Pulgar et al. 1996) as
a result of the Iberian and European plate collision (Boillot and Capdevila 1977;
Srivastava et al. 1990; Alvarez-Marro ´n et al. 1997). Subsequent tectonic inversion
related to the Pyrenean compression led to the north-directed thrusting of basement
units and to the formation of low angle thrust slices or inverted folds in the cover
along the northern margin of the basin (Go ´mez et al. 2002). As a consequence of
these tectonic movements, the present day bathymetry and morphology of escarpments, spurs, canyons and valleys as well as graben structures and horst like
elevations or buried ridges of various sizes have formed (Gallastegui et al. 2002).
One of the largest structural highs on the Cantabrian Margin sensu strictu is Le
Danois Bank (Van Rooij et al. 2010a).
The Page `s Escarpment is located west of this prominent elevation and forms an
E-W oriented structural high (Fig. 11.2), having its highest elevation on the “Aguda
de Fuero” High (Go ´mez-Ballesteros et al. 2014, their Fig. 2) shallower than
500 mbsl (43
59
0 N, 005
42
0 W). The escarpment is bound to the south by the
Gaviero Ca~ non which merges with the Corbiro Ca~ non further west (43
59
0 N,
005
54
0 W) to continue in straight W direction as Corbiro-Gaviera-Ca~ non. To
the N, the escarpment inclines gradually down to 2000 mbsl and then continues
as a steep cliff down to the abyssal plain, while to the W the spur-like structure
11 Water Mass Measurements Around Benthic Communities: A Comparative Study. . .
185
DIC concentrations (Fl€ ogel et al. 2014). There are some reports about CWCs
tolerating different seawater density values in submarine canyons of the Celtic
Margin in the Bay of Biscay (Huvenne et al. 2011) and especially in the Mediterranean Sea (Freiwald et al. 2009). White and Dorschel (2010) claim that the
described sigma-theta density envelope generally corresponds to a sharp pycnocline
that may be helpful in concentrating food particles.
11.1.2 Geological Setting
The Cantabrian Margin bounds the Bay of Biscay in the south characterized by a
narrow shelf in contrast to the Armorican and Celtic Margins in the NE. This
narrow shelf descends rapidly to the deeper parts of the bay exhibiting a continental
slope of variable morphologies (Ercilla et al. 2008). Numerous spurs and canyons
intersect the Cantabrian margin in a downslope direction (Cremer 1981; Kenyon
1987) similar to the Armorican and Celtic Margins (De Mol et al. 2011). The Bay of
Biscay originated from sea floor spreading that began in the Late Permian/Early
Triassic, characterized by normal faults, asymmetric basins, and low angle detachments (Manatschal 2004) which continued until the Lower Cretaceous. During the
Upper Cretaceous a passive continental margin formed (Boillot et al. 1979;
Dere ´gnaucourt and Boillot 1982). The narrow shelf is the result of a complex
tectonic history which culminated in the Oligocene (Tertiary) with a partial closure
of the Bay of Biscay and the intense compression, shortening, and lateral shearing
of the Cantabrian Margin (Thinon et al. 2001; Gallastegui et al. 2002) and the
uplift of the Cantabrian mountains (Pe ´rez-Estau ´n et al. 1995; Pulgar et al. 1996) as
a result of the Iberian and European plate collision (Boillot and Capdevila 1977;
Srivastava et al. 1990; Alvarez-Marro ´n et al. 1997). Subsequent tectonic inversion
related to the Pyrenean compression led to the north-directed thrusting of basement
units and to the formation of low angle thrust slices or inverted folds in the cover
along the northern margin of the basin (Go ´mez et al. 2002). As a consequence of
these tectonic movements, the present day bathymetry and morphology of escarpments, spurs, canyons and valleys as well as graben structures and horst like
elevations or buried ridges of various sizes have formed (Gallastegui et al. 2002).
One of the largest structural highs on the Cantabrian Margin sensu strictu is Le
Danois Bank (Van Rooij et al. 2010a).
The Page `s Escarpment is located west of this prominent elevation and forms an
E-W oriented structural high (Fig. 11.2), having its highest elevation on the “Aguda
de Fuero” High (Go ´mez-Ballesteros et al. 2014, their Fig. 2) shallower than
500 mbsl (43
59
0 N, 005
42
0 W). The escarpment is bound to the south by the
Gaviero Ca~ non which merges with the Corbiro Ca~ non further west (43
59
0 N,
005
54
0 W) to continue in straight W direction as Corbiro-Gaviera-Ca~ non. To
the N, the escarpment inclines gradually down to 2000 mbsl and then continues
as a steep cliff down to the abyssal plain, while to the W the spur-like structure
11 Water Mass Measurements Around Benthic Communities: A Comparative Study. . .
185