The Porcupine Bank is a section of continental crust partially split form the Irish continental shelf by an aulacogen formed during the opening of the Atlantic, beginning in the Permo-Triassic roughly 250 million years ago. Incised into the bank are several submarine canyons, the largest of which is the Porcupine Bank Canyon, 48 km long and 29 km at its widest, and between 3000 and 700 mbsl at termination and head respectively. Around the lip of the canyon, scleractinian Cold-Water Corals (CWC) have thrived for some time, leading to the development of carbonate mounds; large build ups of anastomosing coral framework, baffled sediment and coral skeleton fragments. These unique habitats support increased local species abundance and diversity, acting as a shelter for communities of fishes, crustacea, porifera, echinoderms and actinians.
With no direct connection to a river or land-contiguous shelves, exchange processes occurring at the canyon are hypothetically devoid of any terrestrial and anthropogenic signals. By investigating the palaeorecord of biomineralised CWC skeletons and their associated carbonate mound build-ups, in-situ spectators of flushing and upwelling events, it is anticipated that new insights will be gained into the natural functioning of the upper canyon system and the development of these CWC habitats.
This study aims to assess the validity of signals for environmental change, water mass and nutrient exchange, and sediment flux, preserved in carbonate mounds at the Porcupine Bank Canyon head. This will be achieved through analysis of the geochemistry of live coral skeleton extracted from the canyon edge, as well as fossil coral through the length of a core, and examining microfaunal assemblages present in the sediment record. Here, preliminary results from the research are presented.
iCRAG is funded under the SFI Research Centres Programme and is co-funded under the European Regional Development Fund.