第四纪泥石流活动期与气候期的阶段性耦合过程

PERIODIC COUPLING OF DEBRIS FLOW ACTIVE PERIODS AND CLIMATE PERIODS DURING QUATERNARY

本文参考绝对年代测试结果、基于地球化学分析和区域地层对比等手段 ,对青藏高原东部边缘及华北地区近 40多个第四纪泥石流沉积剖面进行了分析 ,初步认为我国第四纪泥石流沉积主要集中大约在 1 .8～ 1 .6MaB .P .、0 .7MaB .P .、0 .5MaB .P .、0 .1 4MaB .P .～80 0 0 0aB .P .、40 0 0 0～ 2 5 0 0 0aB .P .、80 0 0～ 5 0 0 0aB .P .和 2 0 0aB .P .以来共 7个阶段。泥石流发育与区域乃至全球性气候波动呈现出大致同步的规律性 ;同时 ,不同地区泥石流发育历史存在明显的差异。云南小江流域的泥石流几乎贯穿整个第四纪时期 ,很少间断 ;甘肃白龙江流域第四纪期间泥石流活动受全球气候波动影响明显 ;太行山东麓及北京地区的泥石流活动主要集中在晚更新世以来。

By means of absolute dating, geo chemical analysis, regional stratigraphic correlation, etc., a systemic research was made for more than 40 debris flow profiles located on the eastern margin of the Tibetan Plateau and in North China. The results show that the debris flow mainly erupted in seven times or time intervals below: 1.8～1.6 MaB.P., 0.7 MaB.P., 0.5 MaB.P., 0.14 MaB.P.～ 80 000 aB.P., 40 000～25 000 aB.P., 8 000～5 000 aB.P., and 200 aB.P.～present. The explosive development of debris flow has a regularity synchronous to regional or global climate fluctuation, but debris flows at different areas are much different in development history. For example, debris flow in Xiaojiang basin, Yunnan Province, happened almost throughout the whole Quaternary Period without any interruption, the effect of global climate fluctuation on debris flow in Bailongjiang valley, Gansu Province, were obvious, and debris flow on the eastern slope of Taihang Mountains and in Beijing were mainly concentrated in the late Pleistocene Epoch.