Editing Pollen zone (section)

==History==
The palynological aspects of the system were first investigated extensively by the Swedish [[palynology|palynologist]] [[Lennart von Post]]<ref>{{Cite journal |last=West |first=R. G. |date=October 1970 |title=Pollen Zones in the Pleistocene of Great Britain and Their Correlation |journal=New Phytologist |language=en |volume=69 |issue=4 |pages=1179–1183 |doi=10.1111/j.1469-8137.1970.tb02498.x |issn=0028-646X|doi-access=free }}</ref> in the years before the First World War. By analysing pollen  in [[core sample]]s taken from [[peat bog]]s, von Post noticed that different plant species were represented in bands through the cores.

The differing species and differing quantities of the same species are caused by changes in climate. Von Post was able to confirm the [[Blytt–Sernander]] climatic sequence showing fluctuations between warmer and colder periods across thousands of years. He used local peat sequences combined with [[varve]] dating to produce a regional climatic chronology for Scandinavia.

In 1940 [[Harry Godwin]] began applying von Post's methods to pollen cores from the British Isles to produce the wider European sequence accepted today. It basically expanded the Blytt-Sernander further into the late [[Pleistocene]] and refined some of its periods. Following the Second World War, the technique spread to the Americas.

Currently scientists are focusing a repertory of several different methods on [[core sample]]s in peat, ice, lake and ocean bottoms, and sediments to achieve "high resolution" dating not possible to only one method: [[carbon dating]], [[dendrochronology]], [[Oxygen isotope ratio cycle|isotope ratios]] on a number of gases, studies of insects and molluscs, and others. While often doubting the utility of the modified Bytt-Sernander, they seem to confirm and expand it all the more.