Tag Archives: T5 transect

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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From the Twelve Bens to Inis Meáin and then Inis Cathaigh : T5 Fieldwork – April 2013

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By Matthew Burke and Rich Chiverrell

A belated blog from the BRITICE-CHRONO terrestrial sampling programme in April 2013 when Rich Chiverrell and Matt Burke joined the Durham team – Colm Ó’Cofaigh, Dave Roberts and Dave Evans – for some Transect 5 sampling around Galway Bay. The team were greeted by glorious sunshine as they arrived in Dublin before hightailing it through the Irish Midlands to meet Colm at Clifden in Co. Galway. Surprisingly, for the west of Ireland, the great weather became a constant companion during sampling, for the first week at least, and made it a very pleasant fieldwork programme overall.

WEEK 1: Co. Galway & Co. Mayo: The first week was spent in and around Co. Galway and given there was a lot of ground to cover, we split into two teams during reconnaissance work: rock (Colm O’Cofaigh, Dave Roberts, Dave Evans) and sand (Rich Chiverrell, Matt Burke) hunters. It seems that there are lots of nice erratic boulders in Galway (if they aren’t too angular that is), but only limited sand and gravel. However, Rich and Matt managed to bag samples from Rich’s old stomping ground at Tullywee Quarry, Leenane Delta, Srahlea Quarry, Glennacally Bridge and an unexpected site at Glashmore stream. All in all, a successful start to the Transect 5 OSL programme. Unfortunately, these proved to be the only OSL sites in on the northern side of Galway Bay. Thus, attention was focussed on erratic boulders and bedrock suitable for cosmogenic nuclide (TCN) dating. Although finding the elusive well-rounded boulders could often be a challenge, it would become apparent during the second week, we were spoilt for choice in County Galway.

Following initial success with OSL sampling and having identified a number of targets for TCN sampling, the team set sail for an overnight trip to Inis Meáin (Arran Islands), and hopefully, to collect some well positioned samples. After a smooth and entertaining crossing we were greeted by the team from Inis Meáin Restaurant and Suites who, after conversations over coffee and cake, not only told us where to find the best erratics, also drove us there so we could get a full afternoon of sampling. Word of our arrival soon spread across the small island along with a number of varied rumours as to our purpose. Perhaps the most colourful being that we were filming a horror movie – I suppose the rock saw likely fuelled that one, though the only victims were boulders on this occasion. Inis Meáin proved to boast a lot of very nice erratics and, with some spectacular scenery, was one of the highlights of the trip. Another successful day was followed by a very nice meal, courtesy of our very hospitable hosts at Inis Meáin Restaurant and Suites, and then a well-earned Guinness in the local where many of the islanders were queuing to find out our purpose and about BRITICE-CHRONO generally.

Upon returning to the mainland the following day we completed our final day as a full team with further sampling around the stunning Galway coastline: a further six samples from some roche moutonée and erratics at Rossaveel‐Oughterard.

WEEK 2: Co. Clare: As Rich and Dave Evans returned to the UK (in a noisy fashion due to Rich’s car exhaust falling off), the remaining team (Colm, Dave Roberts and Matt) bagged the final sample sites in Galway during what proved to be a very long and wet day. Almost on cue, after Dave Evans suggested we might be on for continued dry weather during the second week, the heavens opened at the second sample site of the day. Although some good TCN samples were collected at Kilkieran‐Maam Cross a very tired and wet team headed south to County Clare. Despite the long day we still managed to find a spare moment (once we had dried off) for a quick Guinness in the excellent O’Loclain’s Irish Whiskey House.

We expected some difficulty finding granite erratics in the Burren where they are primarily sourced from limestone. However, we started the sampling in Clare with three reasonably well rounded granite boulders after only a little bit of hunting. The success of the first day gave the team some optimism for sampling here. Unfortunately, this was short lived as we found over the coming days that the granite boulders in the Burren seemed to be the only ones along the entire Clare coastline! We spent the next day driving zigzagging along what seemed to be every road in the area, none of which led to any samplable bedrock or sediment. After another long day we eventually found a Bed & Breakfast in Kilrush, where we landed on our feet once again; the owner knew a man with a boat who could to take us to Scattery Island, where we were hopeful to find some samplable outwash sands for OSL. As we were led to believe the weather would be too bad to travel to Scattery Island we began the next day with reconnaissance of a moraine and meltwater channel belt between Kilrush and Kilkee. However, following a last minute phone call to say the boat could make it to Scattery Island and a mad dash back to Kilrush, the team set sail. On the island were greeted by a very nice coastal section that, although containing only limited sand, yielded two OSL samples, as well as a monolith (for radiocarbon dating) from a kettle hole infill.

Although our expectations for finding material for sampling had been somewhat lowered, the final two days of fieldwork proved to provide arguably the best OSL samples from the county. During reconnaissance of the moraine and meltwater channel belt between Kilrush and Kilkee we unexpectedly came across a suite of landforms that appeared to be ice contact subaqueous fans/deltas. Thankfully, being the only source of sand in the area, they had also been quarried, allowing us to finish the fieldwork on a high. Although the last sample of the trip was “less than ideal” from an OSL point of view, a meltwater channel infill identified during earlier reconnaissance work was sampled before a very tired team started the drive to Dublin and found a very comfortable hotel on route for the final night.

Although finding datable materials proved challenging, the weather was good (for the most part), the scenery beautiful, and ultimately a good distribution of samples was collected around Galway Bay. Colm, Dave Roberts and Colin Ballantyne followed up the April fieldwork later in the summer with an equally successful sampling programme from the Connemara coast into Killary Harbour. And Transect 4 fieldwork during March 2014, which allowed a further Hobbitesque ‘there and back again’ visit to the Burren coastline for deltaic sediments at Doolin….. Finally  finally  completing the T5 fieldwork, or has it……..