柴达木盆地西部末次间冰期以来植被特征及其环境变化

发布时间：2018-04-25 20:47

本文选题：孢粉分析 + 植被特征　；参考：《山地学报》2017年05期

【摘要】：柴达木盆地干旱已久,其西部深厚的湖相地层记录着环境演变的过程。本文通过对大浪滩ZK06钻孔沉积物孢粉分析,结合铀系测年数据,根据孢粉沉积运移总浓度变化、区域代表性针叶乔木植物与草本植物彼此消长的变化、蕨类植物孢子峰值出现等特征,探讨了本区末次间冰期以来特征时期的植被演替及环境演变,并对MIS5~MIS2各阶段柴达木盆地西部的气候及环境变化进行了区域对比。初步得出柴达木盆地西部末次间冰期以来伴随青藏高原的阶段性隆升效应以及全球变化的影响下,虽然区域总体植被类型更替不太明显,但在湖水咸化的成盐期孢粉浓度很低,反映出干旱的成盐期环境下植被稀少,在湖水淡化的碎屑沉积期孢粉总浓度较高,表明气候转为湿润,盆地周边山地森林面积增加和盆地草原扩张。MIS5阶段以来总体趋势为盐层厚度逐渐增加、碎屑淤泥层厚度逐渐减少、孢粉总浓度逐渐降低、草本植物花粉百分比逐渐减少、乔木植物花粉百分比逐渐增加。由于本区受冰川融水引起河流径流量的变化对湖水供给影响较大,导致该区湖水水质咸化与淡化以及水位升降的变化因素较为复杂。进入MIS1阶段盆地西部大浪滩盐湖完全干涸,中全新世大暖期并未出现湖泊水位上升和湖水淡化现象,可能受区域构造运动的影响控制。
[Abstract]:Qaidam Basin has been dry for a long time. The deep lacustrine strata in the west of Qaidam Basin record the process of environmental evolution. Based on the sporopollen analysis of ZK06 borehole sediments in Dangtan and the data of uranium series dating, according to the change of the total concentration of sporopollen sediment migration, the variation of the growth and decline of regional representative coniferous Arbor plants and herbaceous plants is discussed in this paper. The vegetation succession and environmental evolution during the characteristic period since the last interglacial period in this area were discussed. The climatic and environmental changes in the western Qaidam basin at various stages of MIS5~MIS2 were compared. Under the influence of the stage uplift effect of Qinghai-Xizang Plateau and global change since the last interglacial period in the western Qaidam Basin, although the change of the regional total vegetation type is not obvious, the sporopollen concentration in the salt-forming period of the lake water is very low. The results showed that the vegetation was scarce in the arid salt-forming period, and the total concentration of sporopollen in the detrital depositional period of lake water desalination was relatively high, which indicated that the climate became humid. The increase of forest area around the basin and the extension of grassland. MIS5 showed that the salt layer thickness gradually increased, the clastic silt layer thickness gradually decreased, the total sporopollen concentration gradually decreased, and the percentage of herbaceous pollen gradually decreased. The percentage of pollen in Arbor plants increased gradually. The variation of river runoff caused by glacial melting in this area has a great influence on the supply of lake water, which leads to the complicated factors of the salinization and desalination of lake water quality and the fluctuation of water level in this area. At the stage of MIS1, the salt lake of Dangtan in the western part of the basin dried up completely, and the lake water level rose and lake water desalination did not appear during the great warm period of the Middle Holocene, which may be controlled by the regional tectonic movement.
【作者单位】：中国地质科学院水文地质环境地质研究所;中国地质科学院矿产资源研究所国土资源部盐湖资源与环境重点实验室;青海省柴达木综合地质矿产勘查院;
【基金】：中国地质科学院基本科研业务费专项经费(YYWF201627) 中国地质调查项目(DD20160054)~~
【分类号】：Q914

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