A smooth encounter with a Porcupine’s back

By Rich Chiverrell

Thirty seven days ago we sailed from Southampton, a journey that has seen us tackle five of the target transects for the NERC Consortium Research Project Britice-Chrono. As the days and nights of hard work pass we have ticked the transects off one-by-one, T4 Irish Sea West – Celtic Sea (53 cores), T3 Irish Sea East (35 cores), T6 Donegal Bay (21 cores), T7 Malin Sea (43 cores). 06:44 hours Friday 22nd August the last of the transects bit the dust, 65 cores stretching from inner Galway Bay, the coast of Connemara out to the Outer Edge, the Porcupine Bank, many many miles of survey line and hundreds of dolphins (keeping Marion happy where is a mammal observer without mammals)……

T5 in the bag

T5 in the bag

Our strategy was to collect three survey transects radiating out from Galway Bay, the first involved our skirting the northern sector and sampling enigmatic ridges fronting the continental shelf break, recovering diamict and shells, but as we progressed west diamict proved harder to find, though we have had some successes. We wonder and debate what age is this glacial terrain? It could be old, very old? Or maybe not, I guess we will find out. Journeying landward we completed one of many criss-crosses of the large ‘Olex’ moraine that appears to front Galway Bay. Popularly named after a survey system fitted to ships, the Olex system collects sea floor morphological data and is fitted to many commercial and private vessels sailing waters around the globe contributing a commercial data collective and providing a valuable window on our sea floor. This moraine often mooted as the maximum limit, but some of the outer moraines we encountered and the shells within their sediments may challenge that conclusion. The terrain that caps the moraine is hard and we expend some time trying to capture datable materials. It feels a little like being between a rock and a hard place, but as night-watch passes the baton onto day-team and vica versa, we are all in the same boat…..

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Weather and sea state intervenes and interrupts our sampling, with the vibrocorer becoming too challenging to safely recover to deck. No rest for us, we head for calmer waters in the shadow of Connemara, with the Twelve Pins in view. A chance occurrence driven by the weather but very useful, as we collect vibro and piston cores from these waters recovering glacigenic materials and some inner marine datable materials that will link well with terrestrial fieldwork in the mountains and rocky lake-strewn lowlands of coastal Connemara. NOC team set the piston core record for the Cruise at just under 8m, we some very enigmatic coarse shelly units in stratified sands…. Eventually the seas relent and a grand voyage to the outer edges of Porcupine Bank is planned to test an extensive glaciations hypothesis, sadly we are confounded by sands, but there is certainly some diamict on the inner sectors of the bank that need explaining. Our final transect is our departure route from Galway Bay, southwest flanking the coastline of County Clare and across a series of moraines, potentially the southern equivalent of the ‘Olex’ moraine, more cores, more diamicts and shells ensue. We are complete 5 transects, 218 cores slightly over the pre-cruise conjectured 75 (?), ‘scientists!!!’ A very big thank you to the BGS and NOC core teams on both legs, the crew of the RRS James Cook for their friendship, good will, humour, company and fantastic support throughout this endeavour. The core length guessing competition has two winners: Stephen during the Day and Riccardo at Night. All that is left is our journey around southwest Ireland, crossing the Celtic Sea once again, but can we resist the lure of the moraines of Bantry Bay………….

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