孢粉证据揭示MIS5a以来福建东北沿海地区人类活动、海平面及气候变化

Palynological Record Revealed Anthropogenic Deforestation,Sea Level and Climate Changes since Marine Isotope Stage 5a in the Northeastern Coast of Fujian Province

通过获取了位于福建省宁德市海岸带的两个钻孔,并使用孢粉分析的方法来重建古环境.光释光和放射性碳十四测年结果表明,钻孔中最老的沉积物来自于深海氧同位素(MIS5a)阶段.孢粉组合中,海相沟鞭藻出现在MIS5a,MIS3早期和早、中全新世阶段,反映了这些时段的海侵事件.MIS5a以来,孢粉组合受控于常绿栎(Quercus)和松属(Pinus),指示了周边地区一直被亚热带阔叶林和松林所覆盖,表现了偏暖的亚热带气候.因此,孢粉证据揭示了末次盛冰期时该地区不存在大幅度的降温.芒萁属孢子和草本花粉的剧增指示了晚全新世以来宁德地区人类活动对天然植被的破坏.

In this study,we analyzed pollen samples from two drilling cores located on the coast near Ningde city of Fujian Province for reconstruction paleoenvironment.Optical stimulated luminescence(OSL)and AMS 14C dating revealed that the oldest age in both cores was marine isotope stage(MIS5a).In pollen assemblages,marine dinoflagellate cysts occurred in MIS5a,early MIS3,early and middle Holocene,reflecting the transgression events in these phases.Since MIS5a,pollen assemblages were dominated by evergreen Quercus and Pinus,indicating that surrounding area was consistently covered by subtropical evergreen broadleaved forest and pine forest,which associated with warm subtropical climate.Therefore,this study confirmed that not obvious cooling occurred during the last glacial maximum(MIS2).Strong increase of Dicranopteris spores and non⁃arboreal pollen reflected that the human activity destroyed natural forest since the late Holocene in Ningde area.