... sediments and become fossilised. The extraction, identification and counting of preserved pollen grains has provided much information on the quaternary. An analysis of pollen found within each horizon shows changes in pollen content over time, indicating changes in the vegetation cover in the area adjacent to the study site, which is then presented on an 'assemblage diagram'. The main purpose of pollen reconstruction is that it provides a link between higher (tree rings) and lower (terrestrial and oceanic) resolution records. It is also possible to map how individual species have migrated over time such as the information available on the deciduous oak tree in Europe. During the LGM, 18,000 B.P. it is known that oak trees only survived in southern Europe in countries such as Spain, Italy and Turkey. During this period the trees managed to secure 'reservoirs' known as refugia, which then, as the climate gradually warmed and the ...

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