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根据开封市西郊9 m岩芯样品的孢粉分析,结合AMS14C测年、粒度分析和历史文献,揭示区域植被对“崇祯大旱”事件的响应。结果表明,岩芯深度0~1.8 m为20世纪中叶的黄河灌淤层和近期堆垫层,1.8~4 m和4~7.8 m分别为1841年和1642-1644年的黄泛沉积;岩芯存在7.8~9 m、5~7.8 m、2~5 m和0~2 m等4个孢粉带,其中5~7.8 m的孢粉带记录了明末“崇祯大旱”事件。该层段下段(6.7~7.8 m)为黄泛早期沉积物,木本植物花粉减少至整个岩芯的最低值,而藜科花粉比例显著升高并占据绝对优势,同时还伴随有旱生植物白刺属和麻黄属花粉出现,蒲公英属和菊科等耐旱植物花粉含量也相对较高,指示一次干旱事件;上段(5~6.7 m)为黄泛后期沉积物,木本植物尤其是松属花粉含量较高,而藜科等旱生植物花粉相对较少,可能是由于松属等木本植物花粉悬浮能力强而被洪水携带至下游,在水流缓慢或近于滞流时沉积,再加上洪水过后黄泛地面接受当地源、区域源和区域外源花粉的缘故。
According to the sporopollen analysis of 9 m core samples in the western suburbs of Kaifeng City and the AMS14C dating, grain size analysis and historical documents, the responses of regional vegetation to the “Chongzhen Severe Drought” event were revealed. The results show that the core depth of 0-1.8 m is the Yellow River silting and depositional layer in the middle of the 20th century, and the 1.8 to 4 m and 4 to 7.8 m are the yellow pan deposits in 1841 and 1642 to 1644 respectively. There are 4 sporopollen belts of 7.8 ~ 9 m, 5 ~ 7.8 m, 2 ~ 5 m and 0 ~ 2 m, of which 5 ~ 7.8 m sporopollen recorded the event of “Chongzhen Severe Drought” in the late Ming Dynasty. The lower part of this interval (6.7 ~ 7.8 m) is the sediment of the early stage of the Yellow River, and the pollen of the woody plants reduced to the minimum value of the whole core. The proportion of Chenopodiaceae pollen increased significantly and occupied absolute superiority. Pollen of Pinaceae and Ephedra appeared, pollen content of drought-tolerant plants such as Dandelion and Compositae was also relatively high, indicating a drought event. The upper section (5 ~ 6.7 m) was the sediment of the late Pantropheraceae, and woody plants, especially pine Pollen content is relatively high, and relatively less pollen of xerophytes such as Chenopodiaceae may be due to pollen suspension of Pinus and other woody plants carried by the flood to the downstream, when the water flow is slow or near stagnant deposition, and then Coupled with floods, the Yellow River flooded the ground to accept the local sources, regional sources and regions of foreign pollen reason.