Abrupt climate change during the last deglaciation: linking records from Greenland to central Europe.

Project Rationale:

The last deglaciation (16,000 – 11,000 years ago) was Earth’s most recent massive climate change but its dynamics are not adequately understood. Multiple warming and cooling episodes occurred during northern hemisphere deglaciation, but records of these events at sufficiently high resolution to track their development have hitherto been largely confined to continental Europe and Greenland. The annually resolved Greenland ice-core records show that several major climatic shifts of the last deglaciation occurred on timescales of decades with some abrupt warmings occurring in 1-3 years [1]. This project aims to understand the origins and mechanisms of transmission of these climate shifts by determining their degree of synchroneity and identifying potential leads and lags. New cores from Windermere in the Lake District contain the highest resolution deglacial record from Britain and Ireland and provide the opportunity to fill in a missing link in the deglacial history of the northern hemisphere [2]. Laminated sediments provide up to annual resolution and pilot studies demonstrate evidence for many of the climatic features recorded in Greenland. Specifically, the interval of the Windermere Interstadial (Bølling-Allerød or GI-1) shows evidence for initial abrupt warming and multiple internal climate oscillations and study of this forms the basis of the project.

Methodology:

Recent coring provides a record of the Windermere Interstadial from both deep and shallow parts of the lake. The project aims are to use a multidisciplinary approach to reconstruct high resolution records of climatic and environmental change using multiproxy methods involving sedimentology, micropalaeontology and geochemistry. Core analysis will use a combination of photography; X-ray radiography; micro-XRF scanner geochemistry; micromorphology using Back Scattered Electron Imagery (SEM) of polished thin section (PTS) and optical microscopy of covered thin sections [2]. Energy dispersive X-ray microanalysis of PTS will complement micro-XRF scanning. Biotic analyses will include molecular (biomarkers) and isotopic proxies to reconstruct palaeoenvironmental conditions and primary productivity and chironomids, which will be used for reconstructing palaeotemperatures, and have indicated that strong temperature gradients existed in NW Europe during the interstadial [3]. Pollen will also be analysed, for correlative purposes and to assess the nature of landscape change in relation to palaeotemperature. Initial radiocarbon dates exist and a follow-up radiocarbon dating programme will be undertaken. Correlation of the cores will involve matching of marker laminae as well as geochemical and palynological markers. Integration of core data with seismic profiles will enable holistic reconstructions of the deglacial history of the region.

Training:

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted within Ocean and Earth Science at the National Oceanography Centre, Southampton and Geography and Environment on the main Highfield campus. Specific training will be given in: (i) high resolution sedimentological and geochemical core analysis and in sample preparation techniques for unconsolidated sediments, (ii) optical and scanning electron microscopy methods including energy dispersive microanalysis methods, (iii) chironomid and pollen analysis methods, and (iv) basic and advanced techniques in organic and isotope geochemistry, including sample preparation and extraction, analysis by GCMS (gas chromatography – mass spectrometry) and isotope ratio mass spectrometry. There will also be opportunities for fieldwork in Windermere.