6.5.2.6 Biogenic Features
Potential clustered carbonate mounds (CM) have been recently reported along the
continental slope of the northern and southern Alboran Sea (Fig. 6.12). Three
different CM fields with still-undetermined biological activity, are located at similar
water depths, on the contouritic terrace of the upper continental slope of the Iberian
Alboran Sea (Ballesteros et al. 2008; Sánchez-Guillamón et al. 2018). The Alcantara
mounds (Western field) are located at depths of between 250 and 282 m off Estepona
(Málaga) (Fig. 6.12b, e), while the Málaga mounds (Central field) (Fig. 6.12c, f), are
located between 220 and 282 m off Málaga city. The Aceitunas mounds (Eastern
field), are located between 142 and 300 m off El Ejido (Almería) and close to Chella
Bank (Fig. 6.12d, g). A total of 150 mounds have been identified in the three fields
that range from 2 to 17 m in height, with maximum lengths of 130 m and slopes of
between 2
and 18
. Generally, they are circular or NW-SE to N-S elongated,
presenting skewed and scalloped distributions. Some have contouritic moats surrounding their basal areas and contourite deposits appear as plastered drifts
overlapping and burying the mound flanks (Ercilla et al. 2016).
Two different CM fields also occur in the African Alboran Sea: the West and East
Melilla Provinces (WMP and EMP) (Fig. 6.12a). The fields are interpreted as being
cold-coral water mounds (Lo Iacono et al. 2014). The WMP is located on the western
upper slope sector of the southern Alboran Sea off Cape Tres Forcas, within a water
depth range between 130 and 620 m. This field comprises two clusters with a total of
103 mounds, within a depth range of 298–590 m. The main cluster is located
between 299 and 420 m water depth, while the second, smaller cluster is located
between 347 and 430 m water depth, in the eastern portion of the WMP. The mounds
are from 1 to 48 m high, with an average height of 10 m, and maximum slopes of
35
. They are almost circular in outline, with maximum lengths of 476 m, although
some are NE-SW elongated in the main cluster and NW-SE elongated in the second
cluster, with maximum lengths of 650 m showing a skewed distribution. They also
present erosive moats. On the other hand, the East Melilla Province (EMP) is located
along the eastern upper and middle slope of the southern Alboran Sea off Cape Tres
Forcas, in water depths of between 230 and 450 m (Comas and Pinheiro 2007). Two
different CM areas comprise up to 10 mounds and ridges (BigOne, Horse, Elephant,
Serpent, Dragon, and New Mounds). BigOne is located at the base of the shallowwater Provencaux Bank, between 300 and 450 mbsl, and comprises three carbonate
ridges: Brittlestar Ridge I-III, while the other mounds are located between 230 and
260 mbsl (Hebbeln et al. 2009). They range from 20 to 100 m high, up to 3000 m in
length, and always have elongate shapes with varying orientations, mainly E-W and
NE-SW. All the mound fields present contourite moats (Comas et al. 2009).
Acoustically, CM are characterized by non-penetrative echoes that produce
transparent pinnacles generally buried under a thin (few milliseconds) sediment
blanket of variable thickness that stands out from the surrounded layered sediments
(Fig. 6.12e, f, g).
180
G. Ercilla et al.
Potential clustered carbonate mounds (CM) have been recently reported along the
continental slope of the northern and southern Alboran Sea (Fig. 6.12). Three
different CM fields with still-undetermined biological activity, are located at similar
water depths, on the contouritic terrace of the upper continental slope of the Iberian
Alboran Sea (Ballesteros et al. 2008; Sánchez-Guillamón et al. 2018). The Alcantara
mounds (Western field) are located at depths of between 250 and 282 m off Estepona
(Málaga) (Fig. 6.12b, e), while the Málaga mounds (Central field) (Fig. 6.12c, f), are
located between 220 and 282 m off Málaga city. The Aceitunas mounds (Eastern
field), are located between 142 and 300 m off El Ejido (Almería) and close to Chella
Bank (Fig. 6.12d, g). A total of 150 mounds have been identified in the three fields
that range from 2 to 17 m in height, with maximum lengths of 130 m and slopes of
between 2
and 18
. Generally, they are circular or NW-SE to N-S elongated,
presenting skewed and scalloped distributions. Some have contouritic moats surrounding their basal areas and contourite deposits appear as plastered drifts
overlapping and burying the mound flanks (Ercilla et al. 2016).
Two different CM fields also occur in the African Alboran Sea: the West and East
Melilla Provinces (WMP and EMP) (Fig. 6.12a). The fields are interpreted as being
cold-coral water mounds (Lo Iacono et al. 2014). The WMP is located on the western
upper slope sector of the southern Alboran Sea off Cape Tres Forcas, within a water
depth range between 130 and 620 m. This field comprises two clusters with a total of
103 mounds, within a depth range of 298–590 m. The main cluster is located
between 299 and 420 m water depth, while the second, smaller cluster is located
between 347 and 430 m water depth, in the eastern portion of the WMP. The mounds
are from 1 to 48 m high, with an average height of 10 m, and maximum slopes of
35
. They are almost circular in outline, with maximum lengths of 476 m, although
some are NE-SW elongated in the main cluster and NW-SE elongated in the second
cluster, with maximum lengths of 650 m showing a skewed distribution. They also
present erosive moats. On the other hand, the East Melilla Province (EMP) is located
along the eastern upper and middle slope of the southern Alboran Sea off Cape Tres
Forcas, in water depths of between 230 and 450 m (Comas and Pinheiro 2007). Two
different CM areas comprise up to 10 mounds and ridges (BigOne, Horse, Elephant,
Serpent, Dragon, and New Mounds). BigOne is located at the base of the shallowwater Provencaux Bank, between 300 and 450 mbsl, and comprises three carbonate
ridges: Brittlestar Ridge I-III, while the other mounds are located between 230 and
260 mbsl (Hebbeln et al. 2009). They range from 20 to 100 m high, up to 3000 m in
length, and always have elongate shapes with varying orientations, mainly E-W and
NE-SW. All the mound fields present contourite moats (Comas et al. 2009).
Acoustically, CM are characterized by non-penetrative echoes that produce
transparent pinnacles generally buried under a thin (few milliseconds) sediment
blanket of variable thickness that stands out from the surrounded layered sediments
(Fig. 6.12e, f, g).
180
G. Ercilla et al.