(Table 1) AMS radiocarbon ages from ODP Hole 169-1034B

High-resolution pollen analysis of laminated marine sediments from ODP Hole 1034B in Saanich Inlet, British Columbia reveals changes in vegetation and inferred climate during the Holocene. Four main pollen zones are discerned using constrained cluster analysis. Although the timing of major vegetation changes at the Saanich Inlet is similar to other study sites in the Pacific Northwest, the composition of pollen assemblage zones is different from the mainland sites. Vegetation assemblages reconstructed from the pollen and spore record include a Douglas-fir (Pseudotsuga menziesii) parkland with abundant grass (Poaceae) and bracken (Pteridium) between 11,450 and 8300 BP (all ages are calibrated calendar years), oak (Quercus) savanna or parkland with high grass and bracken (8300-7040 BP), a mixed deciduous/coniferous forest with oak, western hemlock (Tsuga heterophylla) and Douglas-fir (7040-5750 BP), and the development of modern coastal temperate forest with the marked expansion of cedar (Cupressaceae), western hemlock, spruce (Picea) and Douglas-fir (5750-1050 BP). Climatic periods inferred from the cores include an early Holocene warm/dry interval (11,450-8300 BP), a warm period with mild winters (8300-7040 BP), a period of transitional mid-Holocene climate (7040-5750 BP), and the advent of a relatively cool/wet neoglacial climate after 5750 BP. Modern conifer forests and oak savannas became established by about 3800 BP. The Saanich Inlet pollen record indicates that vegetation and inferred climate change was particularly rapid between 8700 and 8300 BP when grass and bracken abruptly decrease and oak becomes a significant component of the paleovegetation. Because neoglacial conditions have prevailed from 3800 years to present in the Pacific Northwest, factors other than climate, such as anthropogenic modification of the landscape, may be responsible for the persistence of oak savannas.对不列颠哥伦比亚省萨尼奇湾大洋钻探计划（Ocean Drilling Program，ODP）1034B孔的纹层状海相沉积物开展高分辨率花粉分析，揭示了全新世时期的植被演化与推断的气候变迁。 研究通过约束聚类分析识别出4个主要花粉组合带。尽管萨尼奇湾的主要植被变化时间与太平洋西北岸其他研究站点相近，但其花粉组合带的组成却与大陆站点存在显著差异。 从花粉与孢子记录重建的植被组合包括：11450–8300 BP（所有年代均为校准公历年，年代单位为距今（Before Present，BP））阶段，伴生大量禾本科（Poaceae）草本与蕨属（Pteridium）植物的花旗松（Pseudotsuga menziesii）疏林；8300–7040 BP阶段，以高覆盖草本与蕨属为特征的栎属（Quercus）稀树疏林；7040–5750 BP阶段，以栎属、西部铁杉（Tsuga heterophylla）与花旗松为优势的落叶/针叶混交林；以及5750–1050 BP阶段发育的现代海岸温带森林，其中柏科（Cupressaceae）、西部铁杉、云杉属（Picea）与花旗松均出现显著扩张。 从岩芯中推断出的气候阶段包括：全新世早期暖干期（11450–8300 BP）、冬季温和的暖期（8300–7040 BP）、全新世中期气候转型期（7040–5750 BP），以及5750 BP之后相对冷湿的新冰期气候的到来。现代针叶林与栎属稀树疏林约于3800 BP左右形成。 萨尼奇湾的花粉记录显示，在8700–8300 BP期间，植被与推断的气候变化尤为剧烈：草本与蕨属植物骤然减少，栎属成为古植被的重要组成组分。由于新冰期环境自3800年至今一直主导太平洋西北岸区域，因此除气候外的其他因素（如人类活动对景观的改造）可能是栎属稀树疏林得以持续存在的原因。