论文部分内容阅读
新近系红黏土所含动物群生态类型和生态序列表明，７．４～６．１Ｍａ时期黄河中游三趾马动物群以高冠型和混合型动物为主，代表着变化幅度较小的半干旱草原－疏林草原环境．从５．３ Ｍａ开始有一次明显暖湿期，出现大量林栖低冠型动物，甚至在某些动物群出现猿类及爪兽等．３．４ Ｍａ时期动物群是典型干燥草原气候条件下的动物组合．动物群生态序列变化显示上新世的自然环境较晚中新世干旱化程度有明显增强，与动物群性质同步变化的红黏土黏粒胶膜含量是比较理想的古气候变化的替代性指标，具有较强的可信度．
The ecotypes and ecological sequences of fauna in the Neogene red clay suggest that the Triassic fauna in the middle reaches of the Yellow River during the 7.4 ~ 6.1Ma period is dominated by high crown and mixed animals, representing a semi-arid Prairie - sparse forest grassland environment. Starting from 5.3 Ma, there was a clear warm-wet period, with a large number of low-forest-crown animals, and even in some fauna apes and claws appeared. The fauna at 3.4 Ma was an animal assemblage in typical dry steppe climates. The change of fauna ecological sequence shows that the late Pleistocene natural environment had a marked increase in the degree of aridification in the Miocene. The clay content of the red clay in synchrony with the nature of the fauna was an ideal indicator of paleoclimate change. Has a strong credibility.