山东大黑山岛BZ孔黄土沉积特征及其环境意义

发布时间：2018-04-10 03:33

本文选题：黄土岩芯　切入点：光释光年代学　出处：《山东师范大学》2017年硕士论文

【摘要】：由于全球变化对人类和社会的影响愈来愈大,使得人们对全球变化的研究也越来越迫切,对过去气候和环境演变的研究是全球变化研究的一项核心内容。第四纪是距离人类最近的地质历史时期,通过研究第四纪古气候环境的变化,可以很好的为预测未来气候环境演变方向提供可靠依据。中国黄土-古土壤记录了晚新生代以来东亚地区古气候和古环境演变的历史信息,位于中国东部的山东滨海岛屿黄土与黄土高原黄土相比,由于其特殊的地理位置,记录了沿海地区轨道尺度上的气候环境变化和海平面变化。因此,研究该区黄土对揭示中国东部沿海地区古气候和古环境的演化具有特殊意义。本文选择位于山东庙岛群岛最西端大黑山岛上的北庄村南侧BZ孔黄土剖面为研究对象,结合沉积学和粘土矿物学特征分析以及光释光年代学来探讨该区环境演化的历史进程。通过本次研究,我们获得了以下结论:(1)我们在大黑山岛BZ孔黄土剖面的50cm、100cm、150cm和200cm处采集了4个光释光样品,测年结果表明,大黑山岛BZ孔黄土剖面50cm处OSL年龄为26.23±4.92ka,该时间段处于晚更新世末期,由此推断BZ孔黄土剖面顶端全新世和MIS 2阶段黄土缺失,这可能由于沉积后被侵蚀掉或者没有沉积。将大黑山岛BZ孔黄土剖面与同位于庙岛群岛区域内的仙境源剖面和MDS剖面进行地层年龄的对比,推断大黑山岛BZ孔黄土主要为末次间冰期以来堆积的黄土。通过OSL年龄的对比及对剖面沉积时期的推断,进而将大黑山岛BZ孔黄土剖面地层进行划分可确定,剖面0-50 cm为现代耕作层,50-380 cm古土壤层应为L1S1,380-1220 cm黄土层为L1L2,1220-1610 cm古土壤层为S1。(2)通过粒度频率曲线、概率累积曲线、粒度组成等粒度特征分析得出,大黑山岛BZ孔黄土为典型风成沉积物。大黑山岛BZ孔黄土剖面粒度频率曲线呈三峰分布,与洛川黄土相比,剖面粒度频率分布曲线的最低峰与洛川黄土次峰相重合,但该区黄土比洛川黄土在粉砂区多一个次峰,而最高峰比洛川黄土右移,说明大黑山岛BZ孔黄土颗粒较洛川黄土粗,同时表明两个地区黄土在物质来源和形成环境方面还存在着明显差异。大黑山岛BZ孔黄土粒度组成以粉砂(5~63μm)为主,含量平均值为60.1%,其次是砂粒(63μm),含量平均值为21.4%。与洛川及山东内陆黄土相比,平均粒径要粗,与同区域的南长山岛黄土、砣矶岛黄土和北隍城岛黄土相比,粒度组成中的砂粒含量由南向北逐渐增多,这说明该地区黄土可能存在着从北方向过来的近源物质。(3)对大黑山岛BZ孔黄土粒度特征、磁化率特征、色度特征以及粘土矿物组合特征进行综合分析,并与黄土高原黄土相对比得出,该区黄土磁化率值比黄土高原黄土值要低,粘土矿物组合特征与黄土高原不同,说明该区黄土与黄土高原黄土物源和沉积环境不同。结合各气候指标特征分析大黑山岛BZ孔黄土剖面在堆积过程经历温湿到干冷再到冷湿的环境演变历程。1610~1220 cm为S1古土壤层,对应着MIS5阶段,气候较温湿。1220~380 cm为L1L2黄土层,对应着MIS4阶段,气候相对比较干冷。380~0cm为L1S1古土壤层,对应着MIS3阶段,气候较冷湿。剖面堆积过程中伴随着海升与海降,剖面所指示气候环境变化与全球气候波动具有较好的一致性,但剖面沉积特征和物源的不同说明,在大的气候环境背景基本一致的情况下还存在区域性环境的差异。
[Abstract]:The impact of global change on human and society more and more people, makes the study of global change is more and more urgent, the past study on climatic and environmental changes is one of the core contents of global change research. The Quaternary geological history from human recently, through the change of Quaternary climate and environment, can be good for the future direction of the evolution of climatic environment and provide a reliable basis. Chinese loess paleosol records the history information of the ancient climate in East Asia and the ancient environmental evolution since the late Cenozoic, compared to Shandong Binhai island of loess and loess of the Loess Plateau is located in the eastern part of the China, due to its special geographical location, the coastal area scale track record climate change and sea level changes. Therefore, the research has revealed the evolution of Loess China paleoclimate and Paleoenvironment in eastern coastal areas Special significance. This paper chooses Shandong is located in the temple islands west of Daheishan island on the North Village on the south side of the BZ hole loess section as the research object, combined with the analysis of sedimentology and clay mineralogy and OSL chronology of environmental evolution history of the area. Through this study, we obtained the following conclusions: (1) we are in the Daheishan Island hole BZ of loess profile 50cm, 100cm, 150cm and 200cm collected 4 OSL samples, dating results, Daheishan island BZ 50cm OSL hole loess section age was 26.23 + 4.92ka, the time period in the late Pleistocene period, thus BZ loess section top hole the 2 stage of the Holocene and MIS loess missing, this may be due to erosion or deposition after deposition. Compared the Daheishan Island hole BZ loess profile and located in the same temple islands region Wonderland source section and the MDS section of stratum age, To infer the Daheishan island BZ hole is mainly accumulated in Loess since the last interglacial loess. By comparing the OSL age and inference of sedimentary period, then the Daheishan island BZ hole loess stratigraphic division can be determined, 0-50 cm of the profile for the modern soil, 50-380 cm paleosol layer should be L1S1380-1220 cm loess the cm layer is L1L21220-1610 paleosol layer is S1. (2) by size frequency curve, probability cumulative curve, analysis of the characteristics of the composition of the size that the Daheishan island is a typical loess BZ hole aeolian sediments. Daheishan Island hole BZ loess section size frequency curve of three peak distribution, compared with Luochuan loess, frequency distribution the size of the minimum peak curve section and Luochuan loess peak coincide, but the Luochuan loess area of the loess plateau than in silty sand area more than a second peak, and the peak ratio of Luochuan loess is right, that Daheishan island BZ loess particles is Luo hole At the same time that thick loess, loess area in two and the formation of material source environment there are still significant differences. The composition of Daheishan Island hole BZ loess grain size with silt (5~63 m), the average content of 60.1%, followed by sand (63 m), the average content is 21.4%. compared with Luochuan Shandong and the inland loess, the average particle size to rough, with the same area of the South Changshan island of loess, loess and mound compared Isojima beihuangcheng Island loess, sand content gradually increased in size from south to north, which indicates that the Loess may exist near the source material from the north to the (3) to come. The grain size characteristics of Daheishan island BZ hole loess, magnetic susceptibility characteristics, color characteristics and the characteristics of clay minerals were analyzed, and the relative ratio of loess in loess plateau that the Loess magnetic susceptibility value is lower than the value of the Loess Plateau, the characteristics of clay minerals and the Loess Plateau Different, indicating that the area of the Loess Plateau and the loess plateau loess source and different sedimentary environments. Combined with the characteristics of each climate index analysis of Daheishan Island hole BZ loess section in the accumulation process through temperature and humidity to dry to cold wet environment evolution.1610~1220 cm S1 paleosol layer, corresponding to the MIS5 stage, the climate was warm and wet.1220~380 cm L1L2 for the loess layer, corresponding to the MIS4 stage, the climate is relatively dry and cold.380~0cm L1S1 paleosol layer, corresponding to the MIS3 stage, the climate was cold and wet. The profile accumulation process was accompanied by reduced section and the sea sea, indicating climate change and global climate fluctuations have good consistency, but that different sedimentary the characteristics and provenance, climate in the background under the condition of the same there are regional differences in the environment.

【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P532;P512.2

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