白龙江流域第四纪泥石流活动分期研究

Quaternary debris flow stages activity in Bailongjiang river basin

对第四纪泥石流活动周期及其与环境演变关系的研究,可以从宏观上预测现代泥石流发育规律及趋势。选取白龙江流域各阶地典型泥石流沉积剖面,用沉积层测年数据确定泥石流活动期发生年代,对比分析与其它古环境记录(新构造运动史、黄土-古土壤系列、深海δ^(18)O曲线)的关系。研究表明:白龙江流域泥石流活动划分为8个周期,即1.5Ma、0.73Ma、0.565~0.425Ma、0.245~0.165Ma、116.8±9.9Ka、50~25Ka、5~4Ka及3Ka以来。泥石流沉积活动周期与新构造运动活跃期有时间上的共轭性,与深海氧同位素δ^(18)O的奇数段及洛川黄土-古土壤系列中古土壤系列有很好的对应关系,泥石流活动是构造运动与气候变化耦合作用的结果。

With the study of Quaternary debris flow activity cycle and its relationship with the environment evolu- tion, we could predict the development laws and trends of modern debris. Based on typical debris flow deposition profile selected on various terraces in Bailong river basin, the occurrence of debris flow activity in years was de- termined with sediments dating data, and the relationships were compared and analyzed with Neotectonics history and deep - sea oxygen isotope ~180 curve and loess - paleosol series. Studies shown that the debris flow activity in Bailong river basin could be divided into eight activity cycle, namely 1.5Ma,0.73 Ma,0. 565 ~ 0.425 Ma,0. 245 ~ 0. 165Ma, 116.8 ± 9.9Ka,50 -25Ka,5 -4Ka and since 3Ka. Debris flow deposition activity cycle had conjugated in time with the Neotectonics active period and had a good relationship with Odd segment of deep - sea oxygen isotope δ18O curve and paleosol series of Luochuan loess -paleosol series. Debris flow activity was the result of tectonic movement coupled with climate change effects.