古洪水事件判别以及微形态学在古洪水事件判别中的应用

Identification Marks of Paleo-flood Events and the Preliminary Application of Micro-morphology in It

古洪水研究是全球变化研究的热点问题,而研究古洪水的关键是如何有效地寻找及准确判定古洪水平流沉积。在综述古生物学、考古学、沉积学、地球化学对研究古洪水事件作用的基础上,结合微形态研究方法,对古洪水和其他层位薄片的微形态进行了对比分析,表明二者在颗粒特征、矿物组合、孔隙及微垒结等方面存在明显的区别,说明微形态能够用来研究和判别古洪水事件,为古洪水研究提出了一个新的研究思路。

Paleo-flood hydrology study is a hot field in global change study. It is the key for studying paleo-flood events how to look for and identify the paleo-flood slack-water deposits effectively and accurately. In this paper, the effects of paleontology, archeology, sedimentology and geochemistry in studying paleo-flood events are summarized at first, and then the micro-morphological features of paleo-flood deposits and other strata are compared and analyzed based on the theory of micro-morphology. The results show that the grain characteristics, mineral composition, pores and micro-configuration in paleo-flood deposits are obviously different from those in other strata： （1） The grains in the paleo-flood slack-water deposits are fine, well-sorted and subrounded or rounded; （2） Mineral composition in the paleo-flood deposits is similar to that in other strata, but the contents of unstable minerals are relatively low in paleo-flood deposits; （3） Soil in paleo-flood deposits is dominated by clay, and the clay content is second only to that in paleosol; （4） The pores are irregular, and the pore walls are coarse. These reveal that the micro-morphology can be used to research and identify the paleo-flood events.