Constructing a tephrochronology framework for the last interglacial - glacial transition
Lead Research Organisation:
Swansea University
Department Name: Geography
Abstract
Natural archives, such as ice-cores and sediment records from the oceans and lakes provide considerable evidence for the pattern of past climatic and environmental changes. Detailed investigations of such records are fundamental for improving our understanding of natural climatic events particularly as human activities are thought to be altering the global climate system. The last warm episode or interglacial period in particular, (over 100,000 years ago) serves as the closest analogue for understanding the mechanisms, timing and environmental responses that may lead to a glaciated Earth at the end of the current warm episode. Reconstructing the sequence and timing of past climatic events, however, is hampered by large dating errors and the lack of suitable dating techniques. Matching and comparing climatic records from the oceans, continents and ice-sheets in order to understand the environmental responses to climatic events are therefore problematic. A key tool for enabling the synchronisation and direct comparison of different natural archives is volcanic ash. Instantaneous deposition and dispersal of volcanic ash following an explosive eruption often occurs over large geographical areas and these are incorporated as distinct marker layers within different natural archives. In recent years, it has become clear that these ash deposits can actually be traced over thousands of kilometres from volcanic sources, therefore, providing a key technique for the precise correlation of natural archives. A detailed record or framework giving the age and chemical composition of past volcanic eruptions is essential for the successful employment of this technique. The only available archive with the necessary temporal resolution and independent dating control to provide this information is the Greenland ice-sheet. This archive is likely to contain ash deposits from nearby sources such as Iceland and even more distal sources such as Alaska or low-latitude volcanoes. Tracing volcanic events from such sources within the Greenland ice-sheet will enable their precise dating as the ice accumulates in annual layers. More often than not, however, these layers cannot be identified with the naked eye due to the low concentration of ash present in the ice-core material. These horizons however, can be detected through analysis of the chemical signature of the ice itself. A specially-adopted technique will be applied to use these chemical data to pinpoint and extract volcanic ash particles within the ice-core material between 123,000 and 70,000 years ago. Geochemical analysis of each layer will provide a fingerprint of each eruption to identify its volcanic source and to establish links to the same deposit identified in other geological records. In addition to the traditional geochemical technique (electron microprobe) that provides 9 chemical elements, a new method will be employed to provide an additional 30 chemical elements. This technique has as yet, not been used to analyse some of the small volcanic particles contained within the ice-core - but has the potential to advance the specific identification of volcanic sources and differentiation of volcanic ash deposits. Constructing a framework of this kind will provide a detailed record of the timing and frequency of volcanic activity during the end of the last interglacial and the beginning of the last cold episode. This scheme will be of long-term significance for the precise correlation of natural archives to compare the timing of climatic events and the environmental responses in widely separated localities at a critical time in the Earth's history. A better understanding of the pattern of natural climatic events will indeed assist us to predict the likely triggers and sequence of events that may be looming at the end of the current warm episode.
Organisations
People |
ORCID iD |
Siwan Davies (Principal Investigator) |
Publications
Abbott P
(2012)
A detailed framework of Marine Isotope Stages 4 and 5 volcanic events recorded in two Greenland ice-cores
in Quaternary Science Reviews
Abbott P
(2012)
Volcanism and the Greenland ice-cores: the tephra record
in Earth-Science Reviews
Davies S
(2008)
Identification of the Fugloyarbanki tephra in the NGRIP ice core: a key tie-point for marine and ice-core sequences during the last glacial period
in Journal of Quaternary Science
Davies S
(2010)
Widespread dispersal of Icelandic tephra: how does the Eyjafjöll eruption of 2010 compare to past Icelandic events?
in Journal of Quaternary Science
Davies S
(2010)
Tracing volcanic events in the NGRIP ice-core and synchronising North Atlantic marine records during the last glacial period
in Earth and Planetary Science Letters
Davies S
(2012)
Integrating the INTIMATE records using tephrochronology: rising to the challenge
in Quaternary Science Reviews
Davies SM
(2015)
Cryptotephras: the revolution in correlation and precision dating.
in Journal of quaternary science
Svensson A
(2006)
The Greenland Ice Core Chronology 2005, 15-42ka. Part 2: comparison to other records
in Quaternary Science Reviews
Wastegård S
(2009)
An overview of distal tephrochronology in northern Europe during the last 1000 years
in Journal of Quaternary Science
Description | This project led to the discovery of new volcanic horizons identified in the Greenland ice-core records between 100 and 60 ka. These results contribute to constraining the volcanic frequency of Iceland and Jan Mayen. |
Exploitation Route | This project was the first to demonstrate the feasibility of identifiying microscopic ash deposits within the ice-core records between 100-60 ka which provided the foundation for other projects led by Davies (e.g. SMART and TRACE). |
Sectors | Environment |
Description | The research findings form the focus of several public engagement and dissemination events e.g. school talks and general public talks. |
First Year Of Impact | 2006 |
Sector | Environment |
Impact Types | Cultural Societal |
Description | NERC Standard grant |
Amount | £352,133 (GBP) |
Funding ID | NE/F020600/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 04/2009 |
End | 11/2012 |
Description | Philip Leverhulme Prize |
Amount | £70,000 (GBP) |
Organisation | The Leverhulme Trust |
Sector | Charity/Non Profit |
Country | United Kingdom |
Start | 11/2012 |
End | 10/2015 |
Description | Tephra constraints on rapid climatic events (TRACE) |
Amount | € 1,400,000 (EUR) |
Funding ID | 259253 |
Organisation | European Commission |
Sector | Public |
Country | European Union (EU) |
Start | 08/2011 |
End | 08/2016 |
Description | Global Change: Global Threats |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Schools |
Results and Impact | A half-day workshop for 60 year 12 students was held at Swansea University on 15th March to encourage pupils to investigate some of the possible consequences of global changes in the coming decades. An introductory briefing session provided an overview of the science behind environmental hazards that threaten society today and to initiate a discussion on how the risks from those hazards may be affected by global changes such as global warming and population pressures. In small groups, students explored (through worksheets, and internet/library searches) the implications of global change for one hazard. Guidance was provided by academics and PhD students from the School of the Environment and Society at Swansea University. These arguments were presented before the full assembly in the form of a short TV News report. Group topics included wildfires, volcanic eruptions, sea-level change, cyclones, flooding and demographic pressures that increase vulnerability to natural disasters. This was a repeat event, run previously in 2007 and 2009. For 2010, this event was held through the medium of Welsh. Students from Welsh-medium schools have attended in previous years and our workshop fits well with the increasing demand for studying science-based subjects in Welsh. After this workshop, the organisers have been asked to give several talks at local schools. The workshop has established key links to schools in the region. |
Year(s) Of Engagement Activity | 2007,2009,2010 |
Description | Invited outreach lectures |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Invited lectures to secondary and junior schools and general public groups e.g. National Eisteddfod of Wales 2006 (Swansea), 2010 Blaenau Gwent and the Heads of the Valleys (Main Science Lecture), Probus, U3A, Merched y Wawr, Geographical Association, Cylch Wyddonol Caerdydd (Cardiff Scientific Association), Women's Institute, Capel Penarth, Cardiff, Open University Geological Society National Symposium, Capel Bethlehem, Trefdraeth, Clwb Cinio Dinas (Sir Benfro), Abertawe, Hwlffordd, Swansea Science Cafe, Royal Institution of South Wales, Coleg Cymraeg Cenedlaethol. Outreach talks have been presented in English and Welsh Each outreach talk I have presented has lead to subsequent invitations to different groups. |
Year(s) Of Engagement Activity | 2006,2007,2008,2009,2010,2011,2012,2013,2014 |
Description | Media appearances |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Several TV and radio contributions mainly linked to the fieldwork component of the project to Greenland including BBC Wales and Radio Cymru news items, Wedi 7 (Welsh TV magazine programme), Radio Wales Science Café, and the Welsh version of Desert Island Discs (Beti a'i phobol). My research work has also been the focus of a S4C documentary Dibendraw aired in January 2014. Media appearances have been conducted in English and Welsh. Each media appearance has lead to other invitations. |
Year(s) Of Engagement Activity | 2009,2010,2011,2012,2013,2014 |