山东半岛南部近岸海域全新世泥质区沉积特征与物源

发布时间：2018-09-16 21:12

【摘要】：泥质区沉积记录是全新世海洋环境演变的重要信息载体，对“1:25万青岛幅海洋区域地质调查”项目采集的浅地层剖面资料进行精细解释，在山东半岛南部近岸海域发现了一个小型泥质沉积区，该沉积区主要分布在青岛崂山头以北至乳山口附近的近岸海域，整体上平行海岸线呈条带状分布，由岸向海逐渐变薄，等厚深度分布平行于岸线，沉积中心位于鳌山湾海域，AMS14C测年结果表明，该泥质区形成于全新世。本文利用在泥质区采集的76个表层沉积物和3个柱状样沉积物样品的粒度、黏土矿物、碎屑矿物、地球化学元素等分析测试结果，对比研究区周边主要入海河流（大沽河、五龙河、乳山河）沉积物质，结合浅钻（QDQZ03孔）的粒度、元素地球化学、黏土矿物、碎屑矿物和AMS14C测年数据，综合分析了山东半岛南部近岸海域泥质沉积区的沉积特征和物源情况。结果显示：（1）按照Folk分类，研究区底质类型为粉砂、砂质粉砂，其中粉砂占沉积物面积的70%，砂质粉砂占30%。研究区QDZ02、QDZ14、QDZ18柱状样粒度参数分析表明：自西向东，沉积物的颗粒由粗变细，沉积物组分中砂含量变少，细颗粒沉积物增加。自北向南，沉积物的颗粒由细变粗，沉积物组分中砂含量变大，细颗粒沉积物减少。研究区QDQZ03钻孔揭示了整个钻孔浅部（0~8.63m）的沉积物组分含砂量较少，浅部地层水动力环境较弱，比较适于粉砂和黏土的沉积。（2）研究区表层沉积物黏土矿物中，伊利石、蒙脱石含量更接近于黄河沉积物含量。从表层样、柱状样沉积物的伊利石－蒙脱石－（绿泥石＋高岭石）三角端元来看，研究区沉积物黏土矿物与南黄海沉积物相近，更接近于黄河物质，而偏离长江物质。（3）根据研究区表层沉积物碎屑矿物特征，划分了崂山-即墨近岸矿物区、海阳海域矿物区、乳山近岸矿物区。各区物质来源不一，主要是近源与远源物质，其中近源有沿岸和岛屿剥蚀的物质、近岸入海河流携带的泥沙；远源物质有现代黄河物质。（4）利用判别函数选取稀土元素Ce/La和Sm/Nd作为对比元素对，以附近的中小河流（五龙河、乳山河）和我国的大河长江、黄河作为端元，沿3条剖面线计算了DF值。结果显示，研究区沉积物的物质与黄河沉积物接近程度最高。为了消除沉积物粒度的影响，对地球化学环境中比较稳定的元素的比值与稀土元素比值进行了比较，如Ti/Al、Ti/Zr、Gd/Nd、La/Yb、La/Co等。从元素对比分析图上看出，研究区表层沉积物元素比值与黄河沉积物更接近，而偏离长江沉积物质。同时，周边中小河流入海也对其物源产生一定的影响。（5）将研究区表层沉积物中常量元素、微量元素、沉积物底质类型等参数利用SPSS软件进行R型因子分析，按主成分法抽取、最大方差法旋转分析得到4个主因子，，累积方差贡献为89.39%。其中，F1因子元素组合明显与沉积物类型相关，反映了元素分布与沉积物粒度的关系，为亲碎屑元素组合；F2因子代表了生物碳酸盐沉积组分的元素组合；F3因子方差贡献率为9.62%，因子代表组合为砂、粉砂和TiO2；F4因子代表了海水对表层沉积物的影响。综合研究区沉积物的黏土矿物、碎屑矿物、元素地球化学特征，可以得出，山东半岛南部近岸海域泥质沉积区物质来源主要是来自黄河的物质，同时也受到近岸物源的影响。
[Abstract]:Sedimentary records of muddy areas are important information carriers for the evolution of marine environment in Holocene. Detailed interpretation of the shallow stratum section data collected by the project of "1:250000 Qingdao Marine Regional Geological Survey" has been made. A small muddy sedimentary area has been found in the coastal waters of southern Shandong Peninsula. The sedimentary area is mainly located north of Laoshan Tour, Qingdao. In the coastal waters near Rushankou, the whole parallel coastline is in a strip-like distribution, gradually thinning from coast to sea, and the equal thickness depth distribution is parallel to the coastline. The sedimentary center is located in the Aoshan Bay. The results of AMS14C dating show that the muddy area was formed in Holocene. 76 surface sediments and 3 columnar sediments were collected in the muddy area. The grain size, clay minerals, clastic minerals and geochemical elements of the samples were analyzed. The sediments of the main rivers (Dagu River, Wulong River, Rushan River) around the study area were compared, and the grain size, element geochemistry, clay minerals, clastic minerals and AMS14C dating data of the shallow drilling hole (QDQZ03) were analyzed. Sedimentary characteristics and provenance of the muddy sedimentary area near the coast.
(1) According to Folk classification, the sediment types in the study area are silt, sandy silt, of which silt accounts for 70% of the sediment area and sandy silt accounts for 30%. The grain size parameters of QDZ02, QDZ14 and QDZ18 columnar samples in the study area show that from west to east, the sediment grains are coarser and finer, the sand content in the sediment components is less, and the fine sediments are increased. The grain size of the sediment changes from fine to coarse, the sand content in the sediment components increases and the fine sediment decreases.
(2) Among the clay minerals in the surface sediments of the study area, illite and montmorillonite contents are more similar to those in the Yellow River sediments. The material of the river.
(3) According to the characteristics of clastic minerals in the surface sediments of the study area, Laoshan-Jimo offshore mineral area, Haiyang offshore mineral area and Rushan offshore mineral area are divided. Material.
(4) The rare earth elements Ce/La and Sm/Nd were selected as contrast elements by discriminant function, and the DF values were calculated along three sections along the middle and small rivers (Wulong River, Rushan River) and the Yangtze River and Yellow River in China. The results showed that the sediments in the study area were the closest to those in the Yellow River. The results show that the surface sediment element ratio of the study area is closer to that of the Yellow River sediment and deviates from the sediment of the Yangtze River. It has a certain effect on its provenance.
(5) The R-type factor analysis was carried out by SPSS software for the parameters of major elements, trace elements and sediment types in the surface sediments of the study area. Four principal factors were extracted by principal component analysis and the cumulative variance contribution was 89.39%. Among them, the element combination of factor F1 was obviously related to the sediment types, reflecting the elements. The relationship between the distribution and the grain size of sediments is a combination of clastic-like elements; F2 factor represents the element combination of bio-carbonate sedimentary components; F3 factor variance contribution rate is 9.62%; F3 factor represents the combination of sand, silt and TiO2; F4 factor represents the influence of seawater on surface sediments.
According to the geochemical characteristics of clay minerals, clastic minerals and elements in the sediments of the study area, it can be concluded that the material sources of the muddy sediments in the coastal area of the southern Shandong Peninsula are mainly from the Yellow River and are also influenced by the near-shore material sources.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P736.21

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