My current research interests are primarily in the field of mid and high latitude Quaternary histories, with a particular focus on the evolution of continental shelf and island archipelago areas – areas subject to glaciation and repeated glacio-isostatic and eustatic induced transgression-regression sea-level cycles. My main research foci are:
The Late Quaternary Environmental Evolution of the Canadian Arctic Archipelago
My primary research thrust focuses on the Late Quaternary environmental evolution of the Canadian Arctic Archipelago (CAA) and adjacent continental shelf areas. My multifarious interests include the extent and trajectories of Late Wisconsinan local and Laurentide ice during, and subsequent to, the Last Glacial Maximum in the western Arctic region. The pattern and timing of ice retreat, the geomorphic signature of cold-based glacier ice, the the evidence of ice in areas formerly considered to have never been glaciated are all recent research topics. The glacio-isostatic sea-level response to Pleistocene ice-loading histories on Melville and Banks islands in the western CAA is also a fundamental component of this integrated understanding of the deglacial Arctic., as is the timing of the Late Pleistocene to Early Holocene marine transgression in the Bering Strait region. This work, comprising four Arctic field seasons on Banks and Melville islands, has been in close collaboration with John England (NSERC Northern Research Chair) and his research group at the University of Alberta, and Dave Evans at Durham University and supported by the Canadian Government Polar Continental Shelf Program in Resolute Bay, Nunavut.
Central to this work in glaciated complex archipelago settings in the linkage of terrestrial and marine records. In collaboration with the Geological Survey of Canada – Atlantic, and with Anna Pieńkowski at Bangor University, my terrestrial Arctic work has extended into the key marine channels between the Arctic islands, investigating the offshore record for Late Pleistocene glaciation and ice retreat as well as using lithostratigraphy and ice-rafted debris to reconstruct early glacimarine conditions.
Developing from both this terrestrial and marine work is the on-going investigation of rapidly-advancing and catastrophically-collapsing deglacial ice shelves in the western Arctic. In particular, multi-proxy marine core investigations paired with terrestrial geomorphology currently indicate the critical role played by sea-ice in the establishment of such ice shelves, notably in Viscount Melville Sound. Current investigations seek to elucidate the role played by climate or internal ice-sheet instabilities in the formation of such ice shelves.
Late Quaternary Environments of the Celtic Sea
The late Pleistocene to Early Holocene deglaciation of the Celtic Sea, the shallow continental shelf between SW England, south Wales, and southern Ireland is a fascinating area. Subjected to subaerial exposure during and subsequent to the last Devensian/Midlandian glaciation by the British-Irish Ice Sheet, the region was subsequent inundated as global eustatic sea-levels rose. Ongoing work, stemming originally from my PhD (Bangor University, supervised by James Scourse) suggests the possibility of significant glacially-fed lacustrine system in the Celtic Deep Basin, and by implication, the existence of a contiguous land linkage between Britain and Ireland. Marine Molluscs from the area also attest to the environmental changes witnessed during the Holocene marine transgression as well as recording the intense taphonomic modification of molluscan death assemblages characteristic of such sediment-starved high energy environments.
Recent work on British Geological Survey cores from the Celtic Sea has also cast further light on the eustatic sea-level driven onset of seasonally stratified water conditions during the Holocene. In particular, the appearance of the planktonic and pelagic pteropod species Limacina retroversa may serve as an important indicator of stratified conditions and represents a significant sink of carbonate from ocean surface waters in highly productive continental shelf environments.
Marine Molluscs as Palaeoenvironmental Indicators
Connecting with my focus on both Arctic and Celtic Sea palaeoenvironments, the use of marine molluscs as indicators of past sea-level and water-depth and the associated taphonomical modification of those death assemblages in high energy transgressive shelf environments is another area of research. In particular, the selective preservation of different species due to taphonomic modification and the controls on species colonization from limited glacial refugia and the implications for palaeogeographies that that carries are of great interest.
Improving Radiocarbon Methodologies
Last, but by no means least is research into improving high latitude radiocarbon chronologies, primarily centred on establishing meaningful estimates of the marine reservoir effect for use when calibrating molluscan or marine mammal radiocarbon dates. Such an approach is hampered by the post-1950 disruption of global 14C production due to atomic weapons testing as well as various migratory and dietary habits of migratory organisms. Nevertheless, the rigorous statistical treatment of dated materials collected “pre bomb” has so far proved valuable in establishing meaningful values as well as questioning the use of marine mammals as palaeo-sea-ice indicators.