末次间冰期陇西黄土记录与气候不稳定性问题的初步研究  

A Preliminary Study on Longxi Loess Record during the Last Interglacial Period and the Problem of Climatic Instability

作　　者：陈发虎[1] 王建民[1] 

机构地区：[1]兰州大学地理科学系

出　　处：《兰州大学学报（自然科学版）》1996年第4期163-169,共7页Journal of Lanzhou University(Natural Sciences)

基　　金：国家自然科学基金

摘　　要：陇西黄土高原黄土记录的分辨率较高，Ｓ１古土壤厚达８．５ｍ，主要由两个古土壤组和其间黄土层组成．临夏塬堡剖面上可分为５个古土壤层，主要黄土层记录了末次间冰期内的较干冷高粉尘堆积时期．高密度磁化率资料、ＣａＣＯ３含量、粒度和土壤微形态分析显示出，早期一组古土壤发育程度远高于晚期一组．早期一组中最早期一层发育程度最高，亚热带阔叶树成分含量较高，气候最温暖湿润；中间一层主要记录了较湿润的环境，晚期一层形成过程中气候亦较温湿，但曾发生短期较大幅度变化．在这３次温暖阶段之间是２次高粉尘堆积时期．兰州黄土记录说明，不论采取何种对比方案．The Longxi basin is one of the main centres of aerial dust deposition in China, where the loess record has a quite high resolution. Paleosol S 1 is up to 8.5 m thick in the region. It is consists of two paleosol groups(S 1S 1 and S 1S 2) and the loess S 1L 1 between them which recorded the main dust deposition period. There are five paleosol S 1 layers at Yuanbao section in Linxia basin, Gansu. It is shown by short term magnetic susceptibility data, CaCO 3 content, grain size data and soil micromorphology result that the three paleosol layers of paleosol group S 1S 2 have a stronger pedogenesis than paleosol group S 1S 1. The best developed paleosol layer is the one at the beginning of S 1S 2. There are nearly no calcite fragments in micromorphologyically thin sections. The main vegetation in the period was broad leaf forest and grass with a high content of subtropical trees. The climate during the soil formation was warmer than the present. The paleosol S 1S 2S 2 was also strongly developed, but it is coarser than other S 1 paleosol layers, showing that there were high dust depositions in its formation. Paleosol S 1S 2S 1 development is nearly the same as that of paleosol S 1S 2S 3. Two main high dust deposition periods are identified in thin sections of soil morphology. There are two possible correlations between paleosol S 1 layers and the substages of deep sea stage 5 because of dating problems. It is clear, however, that the substage 5e recorded by paleosol S 1 in Longxi loess was not a stable and continuous warm period whatever correlations were used.

关 键 词：古土壤 气候记录 气候环境 冰期 全新世 古气候 

分 类 号：P532[天文地球—古生物学与地层学]