Title: Diagenetic processes in carbonate mound sediments at the south-west Rockall Trough margin
Authors: van der Land, Cees ×
Mienis, Furu
de Haas, Henk
Frank, Norbert
Swennen, Rudy
van Weering, Tjeerd C. E. #
Issue Date: 2010
Publisher: Blackwell Science
Series Title: Sedimentology vol:57 issue:3 pages:912-931
Abstract: Cold water coral covered carbonate mounds at the south-west margin of the
Rockall Trough form ridges several kilometres long and up to 380 m high.
Piston cores obtained at three mound crests reveal the complex internal
structure of the mound build up, with alternating unlithified coral-dominated
intervals and lithified intervals. The most recent lithified interval is covered by
corals embedded in a fine-grained matrix, comprising ca 11 000 years of
continuous mound evolution. Before this time 230Th/U dating shows the
presence of several hiatuses in mound build-up. Aragonitic coral material is
absent or only present as mouldic porosity in the lithified intervals and
coccoliths display widespread overgrowth. Downcore X-ray fluorescence
scanning, computer tomography scan images and petrographic observations
indicate different degrees of diagenetic alteration. The upper boundary of the
most recent lithified interval shows some erosional features, but petrographic
observations indicate that initial lithification of the sediments is not related to
this erosive event or to long-term non-sedimentation, but to earlier sub-surface
diagenesis. Organic matter oxidation and the subsequent lowering of the
saturation state of the carbonate system drives dissolution of the unstable
aragonitic coral skeletons. Depending on the openness of the system, this can
lead to precipitation of a more stable low-magnesium carbonate. A model is
presented describing the sedimentary and diagenetic processes leading to the
formation of lithified intervals.
ISSN: 0037-0746
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Division of Geology
× corresponding author
# (joint) last author

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