NERC Arctic Research Programme
Two permafrost projects funded by NERC's Arctic Research Programme 2010–15 have carried out their second field season of data collection in northwest Canada. CYCLOPS (Carbon Cycling Linkages of Permafrost Systems) researchers collected data on vegetation characteristics, soil properties, peat and carbon gases from sites near Yellowknife, NWT. HYDRA (Permafrost catchments in transition: hydrological controls on carbon cycling and greenhouse gas budgets) researchers collected data on hydrology and permafrost conditions near Inuvik. Information on both projects is available at: http://arp.arctic.ac.uk/
Researchers from the CYCLOPS project have completed a second season in 2014 in Yellowknife. The 2014 summer was characterized by intense smoky conditions due to the several wildfires around the Northwest Territories and prolonged periods without rain. Despite the highway being frequently closed due to forest fire alerts (Figs. 1 and 2), all field sites could be accessed.
Figure 1. Smoky conditions in the vicinity of Behchoko (Rae-Edzo). (Photograph by Cristian Estop Aragones)
As the project focuses on the carbon cycling in disturbed permafrost, CYCLOPS researchers and collaborators established sites where thawing of the permafrost resulted in the formation of wetlands and where spruce forest had been burnt in previous years, causing a potential thickening of the active layer due to the vegetation removal. Additionally, birch and spruce forested areas were also monitored to investigate vegetation controls on permafrost conditions. Fig. 2 shows the black spruce forest site at Mosquito Creek, where the effects of fire on active layer and carbon exchange were studied.
Figure 2. Burn site at Mosquito Creek, near Behchoko. (Photograph by Cristian Estop Aragones)
Measurements of CO2 and CH4 gas exchange, monitoring of soil physical conditions and surveys of vegetation characteristics controlling the frost table were performed throughout the season. Soil cores were sampled and recent carbon accumulation rates aim to shed light on the potential feedback of permafrost thaw to climate change due to the change in soil conditions and vegetation. Fig. 3 shows the soil stratigraphy from a small wetland thought to result from the permafrost thaw in a peatland plateau.
Figure 3. Monolith of moss and organic layer at a CYCLOPS field site. (Photograph by Cristian Estop Aragones)
Monitoring the thermal state of permafrost by automated time-lapse Capacitive Resistivity Imaging
Experiments on geophysical imaging of rock freezing and thawing finished at the University of Sussex Permafrost Laboratory. The experiments involved multiple cycles of active-layer freezing and thawing above artificial permafrost over a two-year period. They used a combination of electrical resistivity tomography, capacitive resistivity imaging and microseismic monitoring of rock fracture. Further information is available at: http://www.sussex.ac.uk/geography/resources/labs/permafrost
Okstindan Research Station, Norway
2013 marked the 45th anniversary of the completion of the Okstindan Research Station in northern Norway, which was led by personnel from the University of Reading. The Okstindan Research Project, founded at that time, continues and to date has resulted in the publication of over 60 research articles concerned with the natural environment of this region, including many on periglacial topics. In 2013 the Station (aka 'The Norway Hut') was occupied for three weeks by a small team led by Dr Steve Gurney, who undertook research including investigations of late-lying snow and the features associated with it (Fig. 4).
Figure 4. Small-scale pronival rampart, Okstindan, northern Norway. (Photograph by Steve Gurney)
The Geological Society of London, Engineering Group Working Party on 'Periglacial and Glacial Engineering Geology.'
This working party continued to prepare a book about the ground conditions associated with UK Quaternary periglacial and glacial environments and their materials, from an engineering geological viewpoint. The periglacial and permafrost chapter by Julian Murton (Sussex) and Colin Ballantyne (St Andrews) has been completed, and the book is expected to be completed in 2015 or 2016. The book will provide a valuable reference work for engineering geologists carrying out site investigations in periglaciated and glaciated terrains. Further information about periglacial ground models and engineering geology in the UK is available from Julian Murton.
Pleistocene periglacial database
Mark Bateman (Sheffield) has continued collaborating with Pascal Bertran (Bordeaux) on a Pleistocene periglacial feature data base and luminescence dating of these features as part of a PhD being undertaken by Eric Andriuex. Results of luminescence dating of periglacial polygons in East Anglia were published (Journal of Quaternary Science, 29, 301-317) with Julian Murton, Jon Lee (BGS and Phil Gibbard (Cambridge), showing that all the patterns belonged to the last glacial cycle, but were multi-phased within in it.
Characterising Periglacial Ramparted Depressions (PRDs) using macroscopic and microscopic methods
Samantha Bromfield (Brighton) is researching relict perennial frost mounds e.g. pingos, palsas and lithalsas, which develop as ground ice forms in near-surface sediments, causing it to heave. The mounds decay to form PRDs. The aim of this research is to identify PRDs by characterising their internal structures at macro- (coring, logging, clast fabric analysis) and micro-scales (thin sections). Micromorphology is an innovative approach to characterising PRDs because frost processes create distinctive and resilient micro-scale features. Discrete and repetitive microstructures along with the geomorphic and sedimentological context will facilitate identification of the genetic origin of these periglacial landforms. PRDs are being investigated at three UK sites: Cledlyn Valley, west Wales; Walton Common, Norfolk; and the Olympic Park, east London. Initial results demonstrate that micromorphology enables the characterisation of suites of microstructures e.g. grain coatings and fabrics, which can be used for comparative studies. Further analysis is underway to determine diagnostic features. Further information is available from: email@example.com
Active-layer failures and arctic climate
A new PhD project has started at Cardiff University, where Huw Mithan is investigating how changes to future Arctic climate will influence the frequency, magnitude, and regional distribution of active layer failures. Fieldwork commenced in 2014 on Svalbard (Fig. 5).
Figure 5. Active layer failures on the north eastern side of Adventdalen, Svalbard. (Photograph by Huw Mithan)
Archaeology and involutions at Farndon Fields (Lower Trent valley, Newark)
Recent archaeological data for an important Late Upper Palaeolithic (LUP) open air site at Farndon (near Newark, Nottinghamshire) are reported in Harding et al (2014). Analysis of in situ flint scatters assign these to both Late Magdalenian and Federmesser phases of the LUP. Lithics lie in alluvial sands that are identified as Windermere Interstadial in age. Alluvium (mapped as Holocene by BGS) is thus locally diachronous. In one trench (6003) (Fig. 6) gravel lobes push up underneath these alluvial sands from underlying Holme Pierrepont terrace sands and gravels. Detailed stratigraphic relationships between the disturbed gravels and alluvial sands however are unclear; either Last Glacial Maximum (LGM) or Younger Dryas cryoturbation may be implied. Holme Pierrepont sediments are OSL-dated in trench 2063A to 22.3±4.7 ka (op cit Fig 2.6) and primary coversands just to the south are OSL-dated in trench 2063B to 11.94±1.02 ka (op cit pg 26) with evidence of fluvio-aeolian laminations at the base. These findings match similar stratigraphy in Younger Dryas coversands at Girton (15km north of Farndon) (Baker et al 2013). Non-periglacial processes such as gypsum karst however may have been involved in the Devon valley. Sherlock (Lamplugh et al 1908) observed loams and sandy gravels "disturbed and piped down" into the irregular surface of the Mercia Mudstone (formerly Keuper Marl), and Howard et al (2009) describe pods and involutions of river gravel injected into bedrock. Mercia mudstones are locally gypsiferous with typical subsurface solution and ground subsidence. This may have accounted in part for gravel deformation in the vicinity.
Figure 6. Stratigraphy in trench excavated in the Lower Trent Valley.
Baker, C.A., Bateman, M.D. and Bateman, P., 2013. The aeolian sand record in the Trent valley, with particular reference to Girton, near Newark. Mercian Geologist,18,108-118
Cooke, N. and Mudd, A. (2014) eds. A46 Nottinghamshire: the archaeology of the Newark to Widmerpool Improvement Scheme 2009. Cotswold Wessex Archaeology, Oxbow Books
Harding, P., Ellis, C. and Grant, M.J. 2014. Late Upper Palaeolithic Farndon Fields. Chapter 2 in A46 Nottinghamshire eds. Cooke, N. and Mudd, A. Cotswold Wessex Archaeology, Oxbow Books
Howard, A.S., Warrington, G., Carney, J.N., Ambrose, K., Young, S.R., Pharaoh, T.C., Cheney, C.S. 2009. Geology of the Nottingham District. Memoir for 1:50 000 geological sheet 126 (England and Wales). British Geological Survey, Keyworth.
Lamplugh, G.W., Gibson, W., Sherlock, R.L. and Wright, W.B., 1908. The geology of the country between Newark and Nottingham (Old Series sheet 126), Memoir of the Geological Survey of Great Britain.
Report prepared by Julian Murton (firstname.lastname@example.org)