Deglaciation, Earth crustal behaviour and sea-level changes in the determination of insularity: A perspective from Ireland

Insularity is defined here in terms of the presence or absence of land-bridge connections between adjacent landmasses. The development of a land-bridge depends upon the existence of a special combination of environmental conditions. These are created through the interaction of climate, sea-level and other physical environmental controls, together with changes in palaeogeography. Such factors operate together to produce conditions suitable for a land-bridge over only relatively short time-scales (10 to 100 years). New palaeoenvironmental data about such factors have emerged in recent years from the Irish Sea and from neighbouring regions. These data, derived from a variety of disciplines, have contributed to earlier discussions about the existence here of land-bridge links in the Late Quaternary. Some of this information, particularly that concerning patterns of Earth crustal behaviour, former ice distributions, deglacial history and sea-level changes, is reviewed. An assessment is given of their significance for possible land-bridge operation at this time.