10000 aB.P.关中蓝田的植被和气候

在阐述陕西关中蓝田县城附近地质环境的基础上,利用孢粉图式分析了该区植被的演替,进而分析了该区10 000 aB.P.的古气候演化特征。从陕西蓝田东城水库剖面17个样品分析发现孢粉和藻类十分丰富,根据孢粉组合特征划分3个组合带,分别代表全新世早、中、晚3个时期的孢粉带。Ⅰ带为蒿属优势带;Ⅱ带乔木花粉激增,早期发育温带阔叶落叶林或针阔叶混交林,晚期是以温带阔叶树或与松混合的疏林草原或森林草原;Ⅲ带是以松、蒿为主的森林草原或疏林草原。结果表明:早全新世气候寒冷而干燥,发育以蒿为主的大片草原;中全新世气候温暖湿润,发育疏林草原和森林草原;晚全新世渐变为干冷,发育以松、蒿为主的森林草原。

Vegetation and Climate Since 10 000 aB.P. in Lantian of Guanzhong Area, Shaanxi Province

Based on the geological investigation in the vicinity of Lantian Town, Guanzhong area of Shaanxi Province, the vegetations since 10 000 aB.P. are reconstructed by using diagrams of pollen and spores in this area, and the climatic changes are revealed. Abundant pollen and spores from 17 samples of the loess section in the Dongcheng reservoir of Lantian Town are found, and three assemblage zones can be recognized during the Holocene. Zone I is characterized by abundant Artemisia. Zone Ⅱ is characterized by the sudden rise of arboreal pollen. The lower part of Zone Ⅱ is represented by temperate deciduous broad-leaf forest or conifers and broad-leaf forest. The upper part of Zone Ⅱ is represented by temperate broad-leaf tree grassland or mixed broad-leaf and pine tree grassland. Zone Ⅲ is characterized by woodland or forest grassland dominated by pine and wormwood. This indicates that in the Early Holocene the climate was cold and dry, and the vegetation was grassland dominated by Artemisia. During Middle Holocene, the climate was getting warm and wet, and the vegetation was tree grassland. The climate changed to dry and cold in Late Holocene, and vegetation changed to pine tree and wormwood grassland.