Paleo-environmental evolution based on high-resolution phytolith since 26 ka B. P. in Huanghe River Delta
Paleo-environmental evolution based on high-resolution phytolith since 26 ka B. P. in Huanghe River Delta
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DOI：
10.1007/s13131-016-0789-x
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发表时间：
2016-01
影响因子：
1.4
通讯作者：
Ping Li;Jun Du;Na Du;Wei Gao-
中科院分区：
文献类型：
--
作者：
Ping Li;Jun Du;Na Du;Wei Gao-
黄河三角洲是世界上最大的河流之一，黄河三角洲自末次冰期以来的古环境演变一直是人们关注的热点问题。根据黄河三角洲沉水DYZK1岩芯的AMS 14C测年与海底剖面声波序列相结合建立的岩心时间序列，对96个沉积物样品进行了植硅体分析。将粒度参数、磁化率与生物地层的垂向变化相结合，重建了黄河三角洲的古沉积和气候条件。研究结果表明，指数参数具有明显的垂向变化规律，26.0ka B.P.以来，黄河三角洲沉积环境经历了河流相-海陆过渡相-潮坪相-浅海相-三角洲相的演化过程。植硅体分析结果如下。首先，将植硅体分为披针形、光滑拉长、刺拉长、隆起、长方形、泡状等类型。在不同的沉积环境中，植硅体含量呈规律性变化，表明同一沉积环境中的植硅体具有一定的稳定性。其次，在潮坪相和三角洲沉积中，披针形、光滑拉长和棘状拉长类型的植硅体含量较高，而在浅海相和河流相环境中含量较小。第三，通过变异系数的对比分析，沉积物中主要植硅体种类的含量变化幅度较大，在海相和河流相沉积中变化幅度较大，而在潮坪相和三角洲相沉积中变化较稳定。
The Huanghe River Delta is one of the world's large rivers, the Huanghe River Delta paleoenvironmental evolution in the Huanghe River has been a hot issue since the Last Glacial. Based on the core time series established by combining AMS 14C dating of Core DYZK1 sediments in submerged of Huanghe River Delta and acoustic sequence on sub-bottom profile, phytolith analyses are carried out on 96 sediment samples. The grain size parameters, magnetic susceptibility are combined with the vertical changes of biostratum to reconstruct the paleo-sedimentary and climatic conditions in the Huanghe River Delta. The study results show that there is a significant vertical change law in the index parameters, and that sedimentary environment of Huanghe River Delta experienced an evolutionary process of fluvial facies-sealand transition facies-tidal flat facies-neritic faciesdelta facies since 26.0 ka B. P.. The phytolith analyses results are as following. Firstly, The phytoliths are divided into lanceolate, smooth-elongated, spiny-elongated, rondel, long rectangular, bulliform and other types. In different sedimental environment, the phytolith content changes regularly, indicating that the phytolith assembles in the same sedimentary environment has a certain degree of stability. Secondly, The lanceolate, smooth-elongated and spiny-elongated categories of phytoliths have greater contents in the tidal flat facies and delta deposition, while have a smaller contents in the neritic facies and fluvial facies environment. Thirdly, Through comparative analysis of variation coefficient, the content of major phytolith categories in the sediment has a greater change amplitude in the sealand transition facies and fluvial facies deposition, while being more stable in the tidalflat facies and delta facies deposition.