Visual and sedimentological
characterisation of
cold-water coral mounds
From a single coral
up to a large mound
Lies De Mol
Itinerary
By train:
Take the train to the train station Gent-Sint-Pieters.
Take tram 1 in the direction of the city centre. Leave
the tram at the stop Korte Meer. It takes about 3
minutes to reach the Academieraadzaal.
By car:
E17 direction Gent, take exit Gent Centrum. Follow
the P-route to the car park Kouter (P5) or car park
Sint-Michiels (P7). It takes about 5 minutes to reach
the Academieraadzaal.
Prof. Dr. J.-P. Henriet (promoter)
Renard Centre of Geology
Department Geology and Soil Science
Ghent University
Prof. Dr. M. De Batist (promoter)
Renard Centre of Geology
Department Geology and Soil Science
Ghent University
Prof. Dr. F. Boulvain
Sediment petrology
Department of Geology
University of Liege
Tuesday 3rd of July 2012
16h00-18h00
After the defense you are kindly invited to
the reception. Please confirm your attendance
before June 23rd (lies.demol@ugent.be).
Prof. Dr. J. Verniers (president)
Research Unit Paleontology
Department Geology and Soil Science
Ghent University
Prof. Dr. D. Blamart
LSCE - Paleoceanography
CEA/CNRS - Université de Versailles
France
Invitation to the public defense of
the thesis submitted for the degree of
Doctor in Sciences, Geology
Academieraadzaal
Voldersstraat 9 - 9000 Gent
Examination committee
P7
Academieraadzaal
Stop Korte Meer
P5
Prof. Dr. A. Vanreusel
Marine Biology Section
Department of Biology
Ghent University
Prof. Dr. S. Louwye
Research Unit Paleontology
Department Geology and Soil Science
Ghent University
Prof. Dr. D. Van Rooij
Renard Centre of Geology
Department Geology and Soil Science
Ghent University
Summary
Cold-water corals are widely distributed along the
northeast Atlantic margin. They are able to form
habitats which vary in size from small patches (few
metres in size) to large reef structures (covering
several kilometres). Additionally, they can even build
up large mound structures up to 300 m high. The
discovery of large cold-water coral mound provinces
along the European continental margin belongs to
one of the most spectacular discoveries of the past
decade. Since then, these coral mounds became a hot
topic within deep-water research resulting in many
multidisciplinary studies (e.g. sedimentological,
(micro)biological, palaeontological, geophysical,
biochemical). At present, more than one thousand
mounds have already been identified within different
mound provinces along the European and Moroccan
continental margins. The best studied examples
along the NE Atlantic margin can be found in the
Porcupine Seabight and on the margins of the Rockall
Trough.
Within the Gulf of Cadiz submarine ridges and steep
fault escarpments occur, which could favour the
settlement of scleractinians and facilitate the buildup of cold-water coral mounds, if the appropriate
environmental conditions are met. One of these sites
is the Pen Duick Escarpment, situated in the El
Arraiche mud volcano field on the Moroccan
continental margin. Up to now, 15 cold-water coral
mounds have been identified on top of this
escarpment with an average elevation of 15 m. This
research will focus on three of these mounds: Alpha,
Beta and Gamma Mound. First, the surface and the
uppermost decimetres of these mounds will be
discussed, followed by a detailed study of three
gravity cores in order to unveil the architectural
framework of the cold-water coral build-ups.
Compared to the mounds in the Porcupine Seabight
and on the margins of the Rockall Trough, the Pen
Duick mounds are much smaller in size, suggesting a
younger age, and making them ideal to study the
initial build-up and evolution of the mounds.
However, little is known about these mounds.
The second part of this thesis focuses on the presence
of cold-water corals and associated oysters along the
continental margin in the Bay of Biscay, where no
coral mounds are observed. In contrast to these well
studied areas in the Porcupine Seabight and the
Rockall Trough, coral occurrences within the Bay of
Biscay, and more specifically the Armorican margin,
are less investigated.
This thesis is based on 4 articles which are published,
submitted or in preparation in international peerreviewed scientific journals:
De Mol, L., Hilàrio, A., Van Rooij, D. & Henriet, J.-P.
(2011). Habitat mapping of a cold-water coral mound
on Pen Duick Escarpment (Gulf of Cadiz). In: Harris,
P.T., Baker, E.K. (eds.). Seafloor Geomorphology as
Benthic Habitat: GeoHab Atlas of seafloor
geomorphic features and benthic habitats. Elseiver
Insights, 645-654.
De Mol, L., Pirlet, H., Van Rooij, D., Blamart, D.,
Cnudde, V., Stuut, J.-B., Duyck, P., De Batist, M. &
Henriet, J.-P. (in preparation). Glacial evolution and
growth of cold-water coral mounds in the southern
Gulf of Cadiz. Sedimentology.
De Mol, L., Van Rooij, D., Pirlet, H., Greinert, J., Frank,
N., Quemmerais, F. & Henriet, J.-P. (2011). Cold-water
coral habitats in the Penmarc’h and Guilvinec
Canyons (Bay of Biscay): deep-water versus shallow
water settings. Marine Geology 282, 40-52.
Van Rooij, D., De Mol, L., Le Guilloux, E., Wisshak, M.,
Huvenne, V.A.I., Moeremans, R. & Henriet, J.-P.
(2010). Environmental setting of deep-water oysters
in the Bay of Biscay. Deep-Sea Research I 57, 15611572.