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Dr Paul Butler

Dr Paul Butler

Honorary Senior Research Fellow

 Peter Lanyon 


Peter Lanyon Building, University of Exeter, Penryn Campus, Treliever Road, Penryn, Cornwall, TR10 9FE, UK


I entered academia relatively late, leaving a 25-year career as an IT consultant in London in 2001 to complete an undergraduate course in Ocean Science at the School of Ocean Sciences at Bangor University.  Immediately after that, I was presented with a PhD opportunity, also at Bangor, in what was then the relatively new field of sclerochronology, the challenge being to use the somewhat random contents of a bag of bivalve shells collected from around the Isle of Man to create a crossdated chronology for the Irish Sea using specimens of Arctica islandica.  As part of the PhD I constructed what was then the longest (at 487 years) shell-based chronology.

Following the completion of my PhD, I worked on the EU FP6 MILLENNIUM project (European Climate of the Last Millennium), helping to construct a 1,357 year shell-based chronology (this for A. islandica shells from the North Icelandic Shelf). As a recognition of the rapid increase in interest in the field of sclerochronology, our group obtained EU funding for a Marie Sklodowska Curie Initial Training Network, ARAMACC (“Annually resolved archives of marine climate change”), which aimed to integrate all aspects of the use of bivalve sclerochronology as a proxy for the marine environment. From 2013-2017 I acted as co-ordinator of this very successful project.


As a result of work done during my PhD, in 2010 I was awarded the Lewis Penny medal by the Quaternary Research Association for pioneering work on the Quaternary stratigraphy of Britain (admittedly a relatively small proportion of the Quaternary). Subsequently, in 2014 I was received the Lyell Fund from the Geological Society of London for noteworthy published research in the Earth Sciences. 

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Research interests

The main focus of my research is the field of sclerochronology, in particular the use of shells from long-lived bivalve molluscs to study the history of the marine environment.  As noted many centuries ago by Leonardo da Vinci, some species of bivalve mollusc deposit annual increments in their shells, so if the date of death of the animal is known, the whole of the shell can be dated at annual resolution by counting increments.  The shells also grow synchronously within populations, which means that we can use the patterns of increment widths just like tree-rings, and build long timelines (“chronologies”) of shell material by starting with a shell with a known date of death, then working back in time by overlapping similar increment width patterns from dead-collected shells.  Geochemical analysis of this dated material allows us to construct time series of proxy-based environmental variables, including seawater temperature, the origin of water masses, and trace element concentrations.   

Synchronous growth also shows that all the shells in a population are responding to some common influence in the environment, so that the increment widths themselves can function as indicators of environmental change.

Most of my research to date has focussed on the very long-lived bivalve Arctica islandica. This species is the longest-lived non-colonial animal whose precise age can be authenticated, and I was a part of the team at Bangor University that identified the longest-lived individual, a specimen of A. islandica that had lived for 507 years.



Dias R, Estrella-Martínez J, Butler PG, Nederbragt A, Hall IR, Barrulas P, Maurer AF, Cardeira AM, Mirão J, Detry C, Bicho N (online 2018). Mesolithic human occupation and seasonality: sclerochronology, δ18O isotope geochemistry, and diagenesis verification by Raman
and LA-ICP-MS analysis of Argyrosomus regius (meagre) sagittae otoliths from layer 1 of Cabeço da Amoreira Mesolithic shell midden (Muge, Portugal). Archaeological and Anthropological Sciences. Archaeological and Anthropological Sciences


Butler PG, Schöne BR (2017).  New research in the methods and applications of sclerochronology.   Palaeogeography, Palaeoclimatology, Palaeoecology, 465(B): 295-299.

Eiríksson J, Scourse JD, Butler PG, Reynolds DJ, Símonarson LA (2017). Langlífar kúskeljar, skeljatímatal og ástand sjávar við Norðurland í þúsund ár. Náttúrufræðingurinn 87 (3–4): 95–108.

Featherstone AM, Butler PG, Peharda M, Chauvaud L, Thébault J (2017).  Influence of riverine input on the growth of Glycymeris glycymeris in the Bay of Brest, North-West France. PLoS ONE

Reynolds DJ, Hall IR, Scourse JD, Richardson CA, Wanamaker AD, Butler PG (2017).  Biological and Climate Controls on North Atlantic Marine Carbon Dynamics Over the Last Millennium: Insights From an Absolutely Dated Shell-Based Record From the North Icelandic Shelf. Global Biogeochemical Cycles 31(12): 1718-1735.

Román-González A, Scourse JD, Richardson CA, Peck LS, Bentley MJ, Butler PG (2017). A sclerochronological archive for Antarctic coastal waters based on the marine bivalve Yoldia eightsi(Jay, 1839) from the South Orkney Islands. The Holocene, 27(2): 271-281.

Sarkissian CD, Pichereau V, Dupont C, Ilsoe PC, Perrigault M, Butler PG, Chauvaud L, Eiriksson J, Scourse JD, Paillard C, Orlando L (2017). Ancient DNA analysis identifies marine mollusc shells as new metagenomic archives of the past. Molecular Ecology Resources, 17 (5):835-853; 10.1111/1755-0998.12679


Marali S, Schöne BR, Mertz-Kraus R, Griffin SM, Wanamaker AD, Matras U,  Butler PG (2016).  Ba/Ca ratios in shells of Arctica islandica – Potential environmental proxy and crossdating tool.  Palaeogeography, Palaeoclimatology, Palaeoecology, 465: 347-361.

Reynolds DJ, Richardson CA, Scourse JD, Butler PG, Hollyman P, Román-González A, Hall IR (2016).  Reconstructing North Atlantic marine climate variability using an absolutely-dated sclerochronological network.  Palaeogeography, Palaeoclimatology, Palaeoecology, 465: 336-346.

Reynolds, DJ, Scourse JD, Halloran PR, Nederbragt A, Wanamaker AD, Butler PG, Richardson CA, Heinemeier J, Eiríksson J, Knudsen KL, Hall IR (2016).  Annually resolved North Atlantic marine climate over the last millennium.  Nature Communications, 7:13502

Román-González A, Scourse JD, Butler PG, Reynolds DJ, Richardson CA, Peck LS, Brey T, Hall IR (2016). Analysis of ontogenetic growth trends in two marine Antarctic bivalves Yoldia eightsi and Laternula elliptica: Implications for sclerochronology. Palaeogeography, Palaeoclimatology, Palaeoecology, 465: 300-306.

Steinhardt J, Butler PG, Carroll ML, Hartley J (2016).  The Application of Long-Lived Bivalve Sclerochronology in Environmental Baseline Monitoring.  Frontiers in Marine Science 3:176


D. Swingedouw, P. Ortega, J. Mignot, E. Guilyardi, V. Masson-Delmotte, P.G. Butler, M. Khodri, R. Séférian (2015). Bidecadal North Atlantic ocean circulation variability controlled by timing of volcanic eruptions. Nature Communications, 6:6545.


I. Bušelić, M. Peharda, D.J. Reynolds, P.G. Butler, A.R. González, D. Ezgeta-Balić, I. Vilibić, B. Grbec, P. Hollyman, C.A. Richardson (2014)Glycymeris bimaculata (Poli, 1795) – a new sclerochronological archive for the Mediterranean? Journal of Sea Research 01/2014.

A.W.R. Seddon, A.W. Mackay, A.G. Baker, H.J.B. Birks, E. Breman, C.E. Buck, E.C. Ellis, C.A. Froyd, …, P.G.Butler, … et al (2014).  Looking forward through the past: Identification of 50 priority research questions in palaeoecology. Journal of Ecology 102: 256-267.


W.M. Brocas, D.J. Reynolds, P.G. Butler, C.A. Richardson, J.D. Scourse, I.D. Ridgway, K. Ramsay (2013).  The dog cockle, Glycymeris glycymeris(L.), a new annually resolved sclerochronological archive for the Irish Sea. Palaeogeography, Palaeoclimatology, Palaeoecology 373: 133-140. 

P.G. Butler, A.D. Wanamaker Jr, J.D. Scourse, C.A. Richardson, D.J. Reynolds (2013).  Variability of marine climate on the North Icelandic Shelf in a 1357-year proxy archive based on growth increments in the bivalve Arctica islandica. Palaeogeography, Palaeoclimatology, Palaeoecology, 373: 141-151. 

L.K. Cunningham, W.E.N. Austin, K.L. Knudsen, J. Eiríksson, J.D. Scourse, A.D. Wanamaker Jr, P.G.Butler, A.G. Cage, T. Richter, K. Husum, M. Hald, C. Andersson, E. Zorita, H.W. Linderholm, B.E. Gunnarson, M-A. Sicre, H.P. Sejrup, H. Jiang and R.J.S. Wilson (2013). Reconstructions of surface ocean conditions from the northeast Atlantic and Nordic seas during the last millennium. The Holocene 23(7): 921-935. 

D.J. Reynolds, P.G. Butler, S.M. Williams, J.D. Scourse C.A. Richardson, A.D. Wanamaker Jr, W.E.N. Austin, A.G. Cage, M.D.J. Sayer (2013).  A multiproxy reconstruction of Hebridean (NW Scotland) spring sea surface temperatures between AD 1805 and 2010.  Palaeogeography, Palaeoclimatology, Palaeoecology 386: 275-285. 

D.J. Reynolds, C.A. Richardson, J.D. Scourse, P.G. Butler, A.D. Wanamaker Jr., I. Ridgway, M.D.J. Sayer, P. Gulliver (2013). The potential of the marine bivalve mollusc Glossus humanus (L.) as a sclerochronological archive The Holocene 23(12), 1711-1720.


G.B. Karney, P.G. Butler, S. Speller, J.D. Scourse, C.A. Richardson, M. Schröder, G.M. Hughes, J.T. Czernuszka, C.R.M. Grovenor (2012). Characterizing the microstructure of Arctica islandica shells using NanoSIMS and EBSD. Geochemistry, Geophysics, Geosystems, 13(4) doi:10.1029/2011GC003961.

I.D. Ridgway, C.A. Richardson, J.D. Scourse, P.G. Butler, D.J. Reynolds (2012).  The population structure and biology of the ocean quahog, Arctica islandica, in Belfast Lough, Northern Ireland. Journal of the Marine Biological Association of the United Kingdom, 92(3): 539-54. 

J.D. Scourse, A.D. Wanamaker Jr, C. Weidman, J. Heinemeier, P.J. Reimer, P.G. Butler, R. Witbaard, C.A. Richardson (2012). The marine radiocarbon bomb pulse across the temperate North Atlantic: a compilation of Δ14C time histories from Arctica islandica growth increments. Radiocarbon, 54(2): 165-186. 

A.D. Wanamaker Jr, P.G. Butler, J.D. Scourse, J. Heinemeier, J. Eiriksson, K.L. Knudsen, C.A. Richardson (2012). Surface changes in the North Atlantic meridional overturning circulation during the last millennium. Nature Communications, 3:899. 


P.G. Butler, A.D. Wanamaker Jr, J.D. Scourse, C.A. Richardson, D.J. Reynolds (2011). Long-term stability of δ13C with respect to biological age in the aragonite shell of mature specimens of the bivalve mollusk Arctica islandica.  Palaeogeography, Palaeoclimatology, Palaeoecology, 302: 21-30.


P.G. Butler, C.A. Richardson, J.D. Scourse, A.D. Wanamaker Jr, T.M. Shammon, J.D. Bennell (2010).  Marine climate in the Irish Sea: analysis of a 489-year marine master chronology derived from growth increments in the shell of the clam Arctica islandicaQuaternary Science Reviews 29: 1614-1632.

G.B. Karney, P.G. Butler, J.D. Scourse, C.A. Richardson, K.H. Lau, J.T. Czernuszka, C.R.M. Grovenor (2010). Identification of growth increments in the shell of the bivalve mollusc Arctica islandica using backscattered electron imaging. Journal of Microscopy, 241(1), 29-36.  7 citations


P.G. Butler, C.A. Richardson, J.D. Scourse, R. Witbaard, B.R. Schöne, N.M. Fraser, A.D. Wanamaker Jr, C.L. Bryant, I. Harris, I. Robertson (2009).  Accurate increment identification and the spatial extent of the common signal in five Arctica islandica chronologies from the Fladen Ground, northern North Sea.   Paleoceanography 24 doi:10.1029/2008PA001715.

P.G. Butler, J.D. Scourse, C.A. Richardson, A.D. Wanamaker Jr, C.L. Bryant, J.D. Bennell (2009).  Continuous marine radiocarbon reservoir calibration and the 13C Suess effect in the Irish Sea: Results from the first multi-centennial shell-based marine master chronology.  Earth and Planetary Science Letters 279: 230-241.

A.D. Wanamaker Jr, A. Baker, P.G. Butler, C.A. Richardson, J.D. Scourse, I. Ridgway, D.J. Reynolds (2009). A novel method for imaging internal growth patterns in marine mollusks: A fluorescence case study on the aragonitic shell of the marine bivalve Arctica islandica (Linnaeus.). Limnology and Oceanography: Methods 7: 673-681.


A.D. Wanamaker Jr, J. Heinemeier, J.D. Scourse, C.A. Richardson, P.G. Butler, J. Eiriksson, K.L. Knudsen (2008). Very long-lived mollusks confirm 17th century AD tephra-based radiocarbon reservoir ages for north Icelandic shelf waters. Radiocarbon, 50: 399-412.

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External Engagement and Impact


Co-ordinator of PAGES 2K network projects:

ARAMATE (The reconstruction of ecosystem and climate variability in the north Atlantic region using annually resolved archives of marine and terrestrial ecosystems)

CLIM-ARCH-DATE (Integration of high resolution climate archives with archaeological and documentary evidence for the precise dating of maritime cultural and climatic events)

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Supervision / Group

Postdoctoral researchers

  • Alejandro Roman Gonzalez

Postgraduate researchers

  • Stella Alexandroff (moving to Penryn)
  • Juan Estrella-Martinez (moving to Penryn)

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