The chronology of palaeoenvironmental changes during the last Glacial-Holocene transition: towards an event stratigraphy for the British Isles

The overall aim of the TIGGER IIb project is to increase our understanding of the manner and rates by which ecosystems responded to climate changes du ring the Last Glacial-Holocene transition. Success in this venture requires better constrained palaeoenvironmental reconstructions than have been achi eved thus far, and the TIGGER project focused. in particular, on three main aims: (1)off-setting the limitations of conventional radiocarbon dating, i n order to provide a more secure chronology of events; (2) increasing the r esolution and precision of palaeoclimatic reconstructions; (3) widening the scope of site-specific palaeoecological investigations. In this paper we f ocus on the first of these strategies, and describe the progress made in de veloping a more coherent timescale for the climate history of the Lateglaci al period. This has been achieved by using a number of independent methods, including calibration of AMS radiocarbon dates obtained from terrestrial p lant macrofossils, MCR estimates of summer temperatures based on coleoptera n records. analysis of stable carbon isotope ratios in terrestrial plant ma crofossils and tephrochronology. Following Bjorck et tri.'s 1998 recommenda tions. we integrate the new results to construct a provisional event strati graphy for the Last Glacial-Holocene transition in the British Isles, which is based on a sequence of features that are believed to be time-parallel. This approach is considered to provide a more coherent Framework for direct comparison of the palaeoenvironmental evidence from Britain with that from elsewhere.