通过对广东湛江湖光岩玛珥湖B孔顶部8～0.6m岩芯较高分辨率的孢粉分析,揭示了该区全新世植被、气候变化的历史:早全新世(约11600～7800cal a BP),木本植物花粉含量为56.0%,其中热带木本植物花粉含量占优势,最多的时期发生在9500～8000cal a BP左右,达到木本植物花粉的60.2%,反映气候热暖潮湿;中全新世(7800～4200cal a BP),热带-亚热带植物花粉含量明显下降,而草本植物和山地针叶植物花粉含量增加,指示了中全新世温度下降;晚全新世4200cal a BP开始,草本植物和山地针叶植物花粉明显增多,揭示出晚全新世湖光岩地区温度、湿度明显下降.研究结果表明,中国南方热带-亚热带地区高温湿润的全新世适宜期发生在早全新世(9500～8000 cal a BP),与全球低纬地区全新世气候变化格局一致.初步认为,全新世早期,在岁差周期的控制下,北半球较强的太阳辐射驱动了热带辐合带(ITCZ)和副热带锋面季风降水带同时向北推移,造成中国热带低纬度地区早全新世最适宜期.湖光岩地区中晚全新世气候干旱趋势和气候波动除了与北半球夏季太阳辐射强度减弱有关外,可能与该时期ENSO的活跃也有一定的联系.
A series of dust pollen samples was collected along N-S transects in east China (18°N to 53°N latitudes). Sample sites extend from the cold-temperate zone in the north to the tropical region in the south. Pollen taxa characterize each region and reflect the natural and devastated vegetation as well as corre- sponding climatic zones. The quantitative pollen data can be used to estimate the spatial distribution of planted and introduced species. Valuable information of human disturbance of the natural forest is evaluated by quantitative comparison between dust pollen and in-situ pollen of protected forest. In addition, percentages of grass pollen vary regularly from north to south that is consistent with spatial distribution of net primary productivity in east China. Among all grasses, Artemisia and the Gramineae carry the clearest signal: their ratio increases northwards and therefore represent a suitable and con- venient tool for palaeoclimate reconstructions.
