Submarine Bedrock of the Irish Atlantic Margin - Updates from the Be_Tar_Drill

11 Feb 2022

Dr. Audrey Recouvreur writes a quick note on her progress.

The Irish continental margin presents diverse geomorphological domains displaying bedrock outcrops that can host a large variety of habitats from shallow to cryptic.

The accessibility and identification of outcrop remains a challenge, due to the difficulty of sampling rock at significant water depths and by limited geological knowledge of sedimentary basins offshore Ireland. The Be_Tar_Drill project looks at bedrock suitability mapping to identify and sample rock types outcropping on the Irish continental margin. The goal is to develop a geological map and stratigraphic model for Ireland’s deep-water territories.

But, where do we even begin to build these data sets necessary for researching for bedrock outcrops for all Irish offshore territories? Firstly, video transects for whole margin were acquired using the remotely operated vechicle Holland 1, which uncovered key bedrock outcrop locations (see image above - hours of videos have been observed to find the holy grail: bedrock, here occuring at 1650 m depth!!)

Secondly, where outcrop was observed in the video transects, terrain variables derived from INFOMAR multibeam echosounder dataset were chosen to delineate seafloor terrain. These were calculated using a combination of Spatial Analyst tools and Benthic Terrain Modeller in ESRI ArcMap 10.8.1.

Finally, using map algebra, a developed novel Bedrock Suitability Index (BSI), have been calculated, highlighting suitable bedrock location in non-surveyed areas.

What comes next?

A research survey next summer aims at collecting bedrock samples based on the bedrock occurrence and BSI maps, with a focus on the southern part of the Irish Continental Margin (including Whittard Canyon, Goban Spur and Porcupine Bank). It will allow to ground truth the spatial mapping contingent with petrographic analysis of physical samples.

Marine Geosciences Research Group

University College Cork

School of Biological, Earth and Environmental Sciences, North Mall Campus, University College Cork, North Mall, Cork City, T23 TK30