西班牙西北部San Isidro和Leitariegos地区全新世孢粉学的比较研究

文中报道了西班牙西北部San Isidro和Leitariegos地区两口钻井全新世孢粉学比较研究的结果.孢粉分种析结果显示了两地孢粉组合成分上的不同.根据从San Isidro地区泥炭沼泽获得的孢粉组合中乔木和灌木花粉百分含量变化,建立了两个组合带.孢粉植物群代表了一个松属占统治地位的森林,桦属、栎属、榛属等花粉含量变化序列可能和气温升高,降雨量增加有关.根据乔木花粉相对丰度变化,Leitariegos地区钻井剖面建立了3个孢粉组合.桦木属花粉含量增加说明是桦树林,栎属和榛属花粉居次要地位,松属花粉含量下降.文中还总结了两个孢粉序列所反映的人类活动、植被演替以及地形景观改变等之间的关系.两地钻井剖面底部碳同位素年代测定表明二者的底部并不同时.

COMPARATIVE PALYNOLOGICAL ANALYSIS BETWEEN THE SAN ISIDRO AND LEITARIEGOS HOLOCENE SEQUENCES, NW SPAIN

Palynological analysis of two drilling cores in San Isidro and Leitariegos Passes, NW of Spain, has been carried out. The comparative analysis of both sequences shows differences regarding the pollen types. Two pollen zones were defined in the San Isidro peat bog on the basis of percentage changes of tree and shrubs taxa. The pollen flora shows a Pinus dominated forest, and Betula, Quercus and Corylus succession probably related to an increase of temperature and precipitation. Three pollen assemblage zones have been defined in Leitariegos on the basis of variations of relative frequencies of tree taxa, and an increase in values of Betula pollen type suggest a birch forest, less important taxa are Quercus, Corylus and Pinus. Some aspects of mutual relationships between human activities, vegetation development and landscape building are outlined in San Isidro and Leitariegos sequences. Radiocarbon dates of both sequences record a diachronism between both deposits.