%0 Journal Article %A Dexin LIU %A Jianhua MA %A Lei GU %A Yanfang CHEN %T The middle and late Holocene pollen record from the Yellow River flooding sedimentary sequence in the western suburbs of Kaifeng City, China %D 2016 %R 10.11821/dlxb201605013 %J Acta Geographica Sinica %P 852-863 %V 71 %N 5 %X

The flooding of the Yellow River has occurred many times near Kaifeng City and formed a relatively complete sedimentary sequence, which provide a rare research carrier for the exploration of the stratigraphic evidence on flood events and its pollen records in the vicinity of Kaifeng. In this research, a 25-m long core was obtained from Jinming campus of Henan University (ZKjm), which is located in the western suburbs of Kaifeng, Henan Province, China. On the basis of detailed pollen analysis, along with color identification, AMS14C dates, grain size and historical documents, sedimentary cycles in the study area were identified, and flood events and their pollen records were revealed since the middle and late Holocene. The results are as follows: According to the sand-clay ratio of grain size in the study area, ZKjm core can be divided into nine sedimentary cycles from bottom to top, and can roughly record eight large flood events. The difference between pollen assemblages is that the percentage of arboreal pollen in flood deposition period is higher than that in neighboring hiatus period, while the percentage of planted Poaceae is lower in ZKjm core. Except individual strata, the boundaries of sedimentary cycle are mainly consistent with the pollen subzones, suggesting pollen can be used as a reference indicator for dividing sedimentary cycles of strata. Notably, sedimentary cycles formed by smaller flood or plurality of intermittent short-term floods within one flood can be identified by pollen index. Therefore, the number of pollen subzones (12) is more than that of sedimentary cycles (9), indicating the accuracy of the cycle division of some intermittent pollen indexes is slightly higher than that of granularity. Due to seasonal changes, the variability of the flowing path of floods and the geographic scope, some floods of the Yellow River that lasted longer may have multiple intermittent short-term floods. However, the local pollen of Kaifeng City mainly deposited during the intermittent floods, which is different from the upper reaches of the Yellow River. Consequently, a pollen subzone may not indicate a specific flood event.

%U https://www.geog.com.cn/EN/10.11821/dlxb201605013