Flora and vegetation of the Quaternary temperate stages of NW Europe:Evidence for large-scale range changes

摘要: Oxygen isotope records from deep marine sediments provide ample evidence that large scale fluctuations in global climate have occurred since about 2·6 Ma (the Gauss—Matuyama boundary, e.g. Shackleton 1987; Ruddiman & Raymo 1988). These climatic resulted alternating periods of cold, cool and warm conditions NW Europe which can be clearly identified, albeit fragmentary fashion, terrestrial sedimentary sequences. The degree change during the Pleistocene has been variable magnitude frequency with earlier cyclicity (over 1·4 — 2·0 0·9 Ma) having a shorter wavelength amplitude than later cyclicity. During period between isotopic suggest predominant 41,000 year cycle (Ruddiman et al. 1986) whilst 0·9Ma to present cold stages occur over 100,000 intervals (Shackleton Opdyke 1976). Figure 1 shows an oxygen record inherent complexity Ma.