Co. Antrim Fieldwork: searching for boulders

Article written by Alex Clark (Royal Holloway University of London)

Fieldwork is all about making discoveries. It’s an opportunity to take what you have learned at your desk and see for yourself if it is true, or if there is more to be said. Usually, it is the latter. Though probably not at the top of your bucket list, a field trip to Co. Antrim, Northern Ireland, is no different. It will provide an opportunity to make some interesting discoveries about the glacial history of Ireland, and yet still leave you scratching your head when you get home. 

However, whilst there is lots to see, there are challenges that stop you from looking and immediately understanding. This was exactly my experience visiting the region for the first time in June 2022.

Why Co. Antrim?

NE Ireland lay at the confluence of the Malin Sea and Irish Sea ice streams which flowed west and southeast, respectively, around the island of Ireland. They supposedly completely disappeared around 16,000 years ago [1], but not in a straightforward manner [2,3,4]. How their recession and other complicating factors impacted the dynamics of terrestrial ice in the north of Ireland is debated.

To help settle the debate, our aim was to find and date glacially-transported boulders and glacially-smoothed bedrock. The yielded ages should tell us when ice thinned and retreated at different stages.

Climb Every Mountain, Search High and Low

Northern Ireland is heavily farmed. As the demand for productive land increases, the ‘natural’ landscape shrinks. This is a problem when you are trying to look for boulders that were plucked, transported, and deposited by a glacier and have not moved for >15,000 years. 

In one unique case we found a good boulder, but soon found out from a farmer that it was moved and repurposed as a scratching rock for the livestock.

Figure 1: A ~2 m tall basalt boulder, easily spotted from the road as we were scouting. However, this one had been moved so livestock could scratch their backs on it, and so was of little use to us. Photo credit: Alex Clark

Our biggest hurdle was therefore reaching the hills, where farming was less prosperous and people were not as likely to have moved the boulders we were after. This often involved driving, but on some occasions required a hike up boggy mountains and near-vertical hillsides.

Sure enough, we had some success in the hills. The imposing volcanic plug called Slemish was a tough climb, but rewarded us with some nicely smoothed bedrock which clearly had warm-based ice flowing over at some point. 

The last day of the trip was fruitful, with seven samples from two locations ending up in our trusty cloth bags! All thanks to some keen-eyed scouting and the permission of some very friendly local farmers and golfers.

Most of the trip before that day, however, was not so smooth.

Boggy Shoes and Nothing to Lose

A walk up the county’s highest peak, Trostan, on day two was a boggy affair. The higher we walked, the further we could see, but the more we climbed into uncertainty. 

Figure 2: Drilling into bedrock at Ballygalley Head. With the kind permission of the Cairndhu Golf Club captains, our final afternoon in the field was spent collecting samples with a backdrop of the North Channel (and the 2nd hole). Photo credit: Bethan Davies

At about 500 metres above sea level, you get a wide view of north Co. Antrim.

Despite all you can view from here, there is not much you can understand at first glance. 

Previous work here has been minimal: glacial landforms in this region have never been mapped, glacially-transported boulders have never been dated, bogs here have never been examined for clues of past glacial activity. Some insightful field reports exist from the 1890s [5], and geologists in the 1920s had a go at interpreting the glacial history of Co. Antrim [6], but little has been done since.

What happened here? What is the significance of what we are looking at? How does this fit in with the bigger picture? 

Figure 3: Taking a few moments sitting on a boulder half way up Trostan, puzzling over what we were looking at. The glacial geomorphology of this region has hardly been studied, and in all honesty, I didn’t think we would find anything useful, yet perhaps we did in the end. Photo credit: Bethan Davies

Sometimes you try your best to know the answers to these questions, but often the answer just has to be “I don’t know”. We were more or less on our own up here, but at the same time we could only gain understanding by building on what was done before.

I’ll Be Back…

And so, the trip eventually ended with samples in the bag and a couple of pairs of boggy socks. Yet there is still so much to see and learn.

I’m not ashamed to admit that I still don’t completely understand what could be going on here, but I can’t wait to come back and try to figure out even just a little bit more of this region’s glacial past – that’s what it’s all about!


1. Hughes, A.L.C., Gyllencreutz, R., Lohne, Ø.S., Mangerud, J. and Svendsen, J.I. (2016) ‘The last Eurasian ice sheets – chronological database and time-slice reconstruction, DATED-1’, Boreas, 45, pp. 1-45.
2. Chiverrell, R.C., Smedley, R.K., Small, D., Ballantyne, C.K., Burke, M.J., Callard, S.L., Clark, C.D., Duller, G.A.T., Evans, D.J.A., Fabel, D., Van Landeghem, K., Livingstone, S., Ó Cofaigh, C., Thomas, G.S.P., Roberts, D.H., Saher, M., Scourse, J.D. and Wilson, P. (2018) ‘Ice margin oscillations during deglaciation of the northern Irish Sea Basin’, Journal of Quaternary Science, 33(7), pp. 739-762.
3. Benetti, S., Chiverrell, R.C., Ó Cofaigh, C., Burke, M., Medialdea, A., Small, D., Ballantyne, C., Bateman, M.D., Callard, S.L., Wilson, P., Fabel, D., Clark, C.D., Arosio, R., Bradley, S., Dunlop, P., Ely, J.C., Gales, J., Livingstone, S.J., Moreton, S.G., Purcell, C., Saher, M., Schiele, K., Van Landeghem, K. and Weilbach, K. (2021) ‘Exploring controls of the early and stepped deglaciation on the western margin of the British Irish Ice Sheet’, Journal of Quaternary Science, 36(5), pp. 833-870.
4. Craven, K.F., McCarron, S., Monteys, X. and Dove, D. (2021) ‘Interaction of multiple ice streams on the Malin Shelf during deglaciation of the last British-Irish Ice Sheet’, Journal of Quaternary Science, 36(2), pp. 153-168.
5. Belfast Naturalists’ Field Club (1894) Proceedings of the Belfast Naturalists’ Field Club, 2(4), pp. 173-278.
6. Dwerryhouse, A.R. (1923) ‘The Glaciation of North-Eastern Ireland’, Quaternary Journal of the Geological Society, 79(1-4), pp. 352-422.

About the Author

I am a PhD student currently working on a project that combines high-resolution geomorphological mapping with new chronological evidence to reconstruct palaeo-ice dynamics in NE Ireland during the Late Glacial (~18,000-15,000 years ago). I am primarily interested in past ice-climate interactions, digital mapping (GIS), and tephrochronology, but enjoy exploring other aspects of geography and the environmental sciences in my research.

If you look closely, you will see me looking like I am having a quick fieldwork nap… but really I was taking pictures of rocks!

2 thoughts on “Co. Antrim Fieldwork: searching for boulders”

  1. Stumbled across your interesting article about boulders. Fascinating! Never thought anyone would be interested!
    We live on a farm BT29 4TE number 10 and we have boulders all around here.
    Several fields in area have been quarried over the years.
    Always wondered how and where they came to be.
    When we put damp proof course into kitchen 20 years ago several biggish boulders needing 2-3 people to lift – were discovered when earth floor dug up!
    If you’re interested come and see our boulders and this area.

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