Through the interplay of a stabilising cold-water coral framework and a dynamic sedimentary environment,
cold-water coral carbonate mounds create distinctive centres of bio-geological accumulation in
often complex (continental margin) settings. The IODP Expedition 307 drilling of the Challenger Mound
(eastern Porcupine Seabight; NE Atlantic) not only retrieved the first complete developmental history of
a coral carbonate mound, it also exposed a unique, Early-Pleistocene sedimentary sequence of exceptional
resolution along the mid-latitudinal NE Atlantic margin.
In this study, a comprehensive assessment of the Challenger Mound as an archive of Quaternary
palaeo-environmental change and long-term coral carbonate mound development is presented. New and
existing environmental proxy records, including clay mineralogy, planktonic foraminifer and calcareous
nannofossil biostratigraphy and assemblage counts, planktonic foraminifer oxygen isotopes and siliciclastic
particle-size, are thereby discussed within a refined chronostratigraphic and climatic context.
Overall, the development of the ChallengerMound shows a strong affinity to the Plio-Pleistocene evolution
of the Northern Hemisphere climate system, albeit not being completely in phase with it. The two major
oceanographic and climatic transitions of the Plio-Pleistocene e the Late Pliocene/Early Pleistocene intensification
of continental ice-sheet development and the mid-Pleistocene transition to the more extremely
variable and more extensively glaciated late Quaternary e mark two major thresholds in Challenger Mound
development: its Late Pliocene (>2.74 Ma) origin and its MiddleeLate Pleistocene to recent decline. Distinct
surface-water perturbations (i.e. water-mass/polar front migrations, productivity changes, melt-water pulses)
are identified throughout the sequence, which can be linked to the intensity and extent of ice development
on the nearby BritisheIrish Isles since the earliest Pleistocene. Glaciation-induced shifts in surfacewater
primary productivity are thereby proposed to fundamentally control cold-water coral growth, which in
turn influences on-mound sediment accumulation and, hence, coral carbonate mound development
throughout the Pleistocene. As local factors, such as proximal ice-sheet dynamics and on-mound changes in
cold-water coral density, significantly affected the development of the Challenger Mound, they can potentially
explain the nature of its palaeo-record and its offsets with the periodicities of global climate variability.
On the other hand, owing to this unique setting, a regionally exceptional, high-resolution palaeo-record of
Early Pleistocene (ca 2.6 to 2.1 Ma) environmental change (including early BritisheIrish ice-sheet development),
broadly in phase with the 41 ka-paced global climate system, is preserved in the lower Challenger
Mound. All in all, the Challenger Mound record highlights the wider relevance of coral carbonate mound
archives and their potential to capture unique records from dynamic (continental margin) environments.