渤海湾西岸QG01孔全新世早中期古气候环境演化研究

发布时间：2018-07-24 11:37

【摘要】：本研究以位于渤海湾西岸北部的QG01钻孔(地理坐标:E117°43′38″,N39°16′30″)沉积物为基本研究材料,总结了沉积物粒度特征、粘土矿物分布和含量变化,并结合光释光年代学和前人的研究成果,探讨了渤海湾西部晚更新世自全新世中期的气候环境变化特征和过程,得出结论如下:1.QG01孔全新世以来受河流供给以及海平面的变化的影响沉积速率呈现三个阶段变化,分别是:18-8.5ka陆上河流控制的低速率沉积;8.5-5.4ka海平面上升和河流进积共同作用的中等速率沉积,5.4ka至今河流供给加强的高速率沉积。2.研究区在全新世经历了一次明显的海陆更替过程,由洪泛平原相、潮滩相过渡到三角洲相,其沉积环境的演化是海平面变化和河流进积综合作用的结果。早期主要受海平面控制,中晚期主要受河流进积作用控制,特别是黄河三角洲对海岸变迁的控制。3.本区粘土矿物组合形式为伊利石—绿泥石—高岭石—蒙脱石。四种粘土矿物的含量以及伊利石KI指数在垂向上的变化特点显示7.2-5.6ka间研究区可能有来自黄河的物质混入。4.(伊利石+绿泥石)/(蒙脱石+高岭石)的比值可以作为古气候演化的替代指标,结合伊利石KI指数能够反映出古气候演化的冷暖周期。古气候演化替代指标的M-K检验结果显示:末次盛冰期结束后至早全新世,研究区经历了一个逐渐的升温过程,其中14-8.5ka BP升温最为显著。进入全新世早中期升温趋缓,期间(8.3-7.9ka BP)有一次不太显著的降温事件,但是没有改变升温的总趋势。
[Abstract]:In this study, the sediment from the QG01 borehole located in the northern part of the west coast of Bohai Bay (geographic coordinates: E117 掳43N38 "N39 掳1630") was used as the basic research material, and the grain size characteristics, clay mineral distribution and content changes of the sediments were summarized. Combined with photoluminescence chronology and previous research results, the characteristics and processes of climate and environment changes in the western Bohai Bay since the middle Holocene were discussed. The conclusions are as follows: 1. The sedimentation rate of QG01 hole has changed in three stages since the Holocene due to river supply and sea level change. They are the medium rate deposits controlled by low rate sediments controlled by the overland rivers of: 18-8.5ka 8.5-5.4ka and fluvial progradation, respectively. The medium rate deposits have been increased by 5.4ka and the high rate deposits have been enhanced by the river supply up to now. During the Holocene, the study area experienced an obvious process of sea and land turnover, from flood plain facies, tidal flat facies to delta facies. The evolution of sedimentary environment was the result of the integrated action of sea level change and river progradation. In the early stage, the sea level was the main control, and the middle and late stages were mainly controlled by river progradation, especially by the Yellow River Delta, which controlled the coastal vicissitude. The clay mineral assemblage form is Illite-chlorite-kaolinite-montmorillonite. The contents of four kinds of clay minerals and the vertical variation of Illite Ki index indicate that there may be material mixed with the Yellow River in the study area of 7.2-5.6ka. The ratio of (Illite chlorite) to (montmorillonite kaolinite) can be used as an alternative index of paleoclimate evolution and the Illite KI index can reflect the cold and warm periods of paleoclimate evolution. The M-K test of paleoclimate evolution substitution index shows that from the end of the last glacial peak to the early Holocene, the study area experienced a gradual warming process, in which 14-8.5ka BP temperature rise was the most significant. In the early and middle Holocene, there was a less-obvious cooling event in the period (8.3-7.9ka BP), but it did not change the general trend of temperature rise.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P532

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