CE14001 Celtic Explorer Developing Geotechno Stratigraphies Survey (Leg2) Irish Sea 2014

This eight day survey (leg 2), led by University College Cork (UCC) took place on board R.V. Celtic Explorer in the North West and central Irish Sea in January 2014. Leg1 (CE13003) concentrated on North West Celtic Sea and offshore Dungarvan- the Saltees, collecting cores and seismic data for palaeoenvironmental and geotechnical studies. The overall objective of the surveys was to understand the control of palaeoenvironments on sedimentary sequence development and how, in turn, this controls geotechnical sub-seabed properties. The purpose of this survey was to perform in situ Cone Penetration Testing (CPTu) in order to groundtruth previously collected seismic data and obtain geotechnical data regarding the nature of sediment at depth. This involved a collaborative effort undertaken by University College Cork, MARUM (University of Bremen), the Marine Institute and Gaelectric Developments Ltd. The main area of focus was the north-western Mudbelt area of the Irish Sea; a large area earmarked for offshore renewable energy development. The Lambay Deep area was also the subject of a seismic survey to identify buried tunnel valleys and one site for CPT deployment. Under a 24 hour work routine, 17 sites were surveyed using the MARUM designed and built Geotechnical Offshore Survey Tool (GOST). In total some 306.17 m of good, in situ sub-seabed geotechnical data was collected. A Marine Mammal Observer was also on board to conduct visual surveys for cetaceans. The key objectives of the proposal are: (1) to determine the sub-seabed stratigraphy (the succession of sedimentary layers below the seabed) in high probability areas for renewable energy farm development (2) to obtain physical samples from the sub-seabed for geotechnical analysis (3) to obtain and analyse physical samples from the sub-seabed to determine the palaeo-environmental development of the seabed and submerged coastline and low-lying terrestrial areas through time (4) to map the spatial distribution and morphological characteristics of sedimentary bedforms and collect physical samples to advance our understanding of seabed mobility in key areas and to advise the industry on optimised cable emplacement strategy in target areas (5) to provide this data as (a) base-line data to both government bodies and industry for both site selection and future environmental assessment, and (b) key data to allow for realistic financial modelling for cost-effective installations and maintenance of offshore renewable energy farms.