科尔沁沙地南缘虻石沟黄土地层孢粉分析与古环境的探讨

本文通过对科尔沁沙地南缘虻石沟黄土地层孢粉分析, 划出四个花粉带。Ⅰ带是榆, 榛, 蒿; Ⅱ和Ⅳ带是蒿、藜; Ⅲ带是蒿、菊科、禾本科。从中更新世至晚更新世期间植被与气候变化, 经历了榆树疏林草原(温和偏湿)→半荒漠草原(干冷)→干草原(温凉稍湿)→半荒漠草原(干冷)多次变化过程。孢粉分析表明, 我国北方黄土地层孢粉沮合特点, 由种类贫乏喜干旱的草本花粉组成, 木本花粉数量很少, 反映黄土堆积的干燥气候占主导。植被景观多半是森林草原, 疏林草原, 干草原, 榆树疏林草原, 半荒漠草原或荒漠草原型植被。

A Study on the Pollen Analysis and Paleoenvironment of Loess Stratigraphy in Menshigou in South Edge of Horgin Sandy Land

Through pollen analysis of loess stratigraphy in Menshigcu in south edge of Korgin sandy land, It can be divided into 4 pollen dominant zones: 1. Ulmus, Corylus, Artemisia, 2. Artemisia, Chenopodiaceae. 3. Artemisia, Compositae and Gramineae. Thia paper indicated that the successive series of palaeobotony and palaeoclimate were from Ulmus sparse forest steppe to subdesert steppe, and then steppe and subdesert steppe. At the same time, the changes of the climate fluctuated from warm and slight humid to cool and slight wet, then cold and dry. According to the data of paleo magneticis and rock stratigraphy, the profile was clearly showed 4 horizons: first horizon was named Lishi loess, second-fouth horizon was attribured to Malan loess, They were formed in pleistocene and late pleistocene, respectively. As compared with Laiotong mountains, Tongzhetang in Peijing and Liuxhugou in Shaanxi Province, it was dominant in herb pollens, whereas the amount of wood pollens was less, even, poor in the loess stratigraphy of Horgin sandy land. All of these charateristics reflected that dry climate was dominant during that periods. The types of vegetation consisted of forest steppe, dry steppe, Ulimus sprese forest steppe, subdesert steppe and desert steppe.