南黄海中部泥质区柱状样沉积物中木质素的垂直分布特征

发布时间：2018-04-10 21:46

本文选题：木质素 + 陆源有机物　；参考：《中国海洋大学》2014年硕士论文

【摘要】：广阔的陆架边缘海是陆海物质互相交汇的活跃地带，，其发育的泥质区记录了丰富的古海洋环境信息。我国南黄海中部泥质区自全新世以来沉积记录连续，尤其是西部边缘海域以其较低的沉积速率完整记录了上万年的古环境变化信息，为反演陆地古气候、古植被提供了有力依据。本文测定了南黄海中部泥质区N02（122o38.843'E，36o1.871'N）柱状样沉积物中木质素含量及其相关参数，探讨了该区域陆源有机物中木质素的母源植被类型、降解方式和程度等信息，结合参考文献推断的柱样沉积年龄，初步分析了南黄海中部泥质区沉积有机质在上千年尺度上的变化及其对环境的响应。本文对N02柱样中木质素含量、植被参数、降解参数等的研究得到了如下主要结果和结论： 1. N02柱样中Σ8介于0.03~0.3mg/10gds，在-46cm附近达到整根柱子最大值0.3mg/10gds，继而减小至-87cm附近的0.06mg/10gds，-87cm以深以0.1mg/10gds为中值线稳定波动（且整体较低）。推测2~3ka B.P.以前，黄河入海泥沙量仅为现代黄河的大约1/5；且2.8ka B.P.以前沉积物粒径较粗导致吸附的陆源有机质较少。这两点是-87cm以深区段Σ8小于上部的主要原因。-87cm以深区段，沉积物的陆源供给并无显著变化，加之南黄海中部泥质区较为稳定的还原沉积环境可能是该区间内Σ8变化不大的主要原因。 2. N02柱样中S/V介于0.30~3.4之间，0~-20cm和-210~-230cm区段S/V大部分小于0.6，C/V则均大于0.05，表明N02柱样陆源有机物以被子植物草本组织为主，少量区间有裸子植物的集中输入，与现有的全新世中后期黄河流域植被以草本组织为主的研究结论相吻合。其次，-75~-120cm区间S/V和C/V的变化趋势与0~-75cm和-75~-260cm显著不同。而全新世中后期气候呈现温润-较干冷-干冷三个阶段，这可能是S/V、C/V分阶段变化的原因。再者，宋金年间（800a B.P.）蒙古游牧民族南下对黄河流域草原的破坏可能导致0~-20cm区间被子植物显著减少，裸子植物集中输入。此外，近2000年来黄河河道的复杂性使其裹挟入海的陆源植物碎屑的种类和数量发生变化，致使0~-75cm区间S/V、C/V波动显著。 3. N02中P/(V+S)与Σ8呈现一级衰减相关趋势，表明去甲基/去甲氧基降解是该柱样中陆源有机物的主要降解方式。而(Ad/Al)V、P/(V+S)、(Ad/Al)S自上而下稳定的波动趋势表明沉积物中木质素的降解主要发生在河流迁移入海的过程中，而在被埋藏之后则降解不显著。这两点结论与N02所处的还原埋藏环境相吻合。 4.根据年代推测，N02柱样中Σ8在-100cm、-160cm、-180cm、-225cm附近均有较显著的增加，推测其分别对应于东亚冬季风的增强期3.2~3.1、4.4~4.2、5.0~4.7和5.9~5.5ka B.P.，尤其是-160cm附近，Σ8呈现多次剧增，这与研究显示的“4.2ka”事件多次、反复的东亚冬季风增强的特征相吻合。伴随东亚冬季风的增强，强度加大的黄海沿岸流可携带更多的陆源有机物，导致陆源物质向外海的输送增加，这是Σ8响应环境变化的方式之一。其次，柱子由底及顶Pon/P大体逐渐减小，且变化的分节点与东亚冬季风由强至弱的时间点也较为吻合（6.0~4.2~1.8~0ka B.P.），表明Pon/P在一定程度上也能响应东亚冬季风的强弱变化。
[Abstract]:The vast continental shelf marginal sea is a sea crossing zone of active material, the development of the mud area recorded the rich ancient marine environment information. Since the Holocene sedimentary record in the Southern Yellow Sea Mud Area in our country continuously, especially the western edge area for its low deposition rate of complete recorded paleoenvironmental change information for thousands of years, for the inversion of Terrestrial Paleoclimate, paleo vegetation provides a strong basis. The Central South Yellow Sea mud area was measured by N02 (122o38.843'E, 36o1.871'N) the content of lignin in columnar sediments and its related parameters, discusses the source of vegetation type lignin domain terrigenous organic matter in this region, the degradation of information the way and extent, column sediment age combined with references, a preliminary analysis of the Central South Yellow Sea Mud Area of sedimentary organic matter in thousands of years on the scale of change and its response to the environment.
In this paper, the main results and conclusions of lignin content, vegetation parameters and degradation parameters in N02 column samples are obtained as follows:
1. N02 column in 8 Sigma is 0.03~0.3mg/10gds, reach the whole column in the vicinity of the -46cm maximum value 0.3mg/10gds, and then decreased to near -87cm 0.06mg/10gds, -87cm to 0.1mg/10gds for the median line to deep stable fluctuation (and lower overall). We speculated that 2~3ka B.P. before the the Yellow River sea sediment amount is only about 1/5 of modern the Yellow River; 2.8ka and B.P. sediments before coarse grain size leads to the adsorption of terrigenous organic matter less. These two points are the main reason for the -87cm.-87cm to less than 8 of the upper part of the deep section Sigma in deep section, there is no significant change in the supply of terrigenous sediments, sedimentary environment and reduction of south central the Yellow Sea mud area relatively stable may be the main reasons of the small 8 sigma changes within the interval.
Between 2. N02 cores in S/V between 0.30~3.4, 0~-20cm and -210~-230cm section of most of the S/V is less than 0.6, C/V greater than 0.05, showed that the N02 cores of terrigenous organic matter in herbaceous angiosperm tissue, a small range of concentration input of gymnosperms, research and conclusion of vegetation in the the Yellow River River Basin in late Holocene in the existing organization based in herbage consistent. Secondly, the -75~-120cm interval S/V and the change of C/V and 0~-75cm and -75~-260cm were significantly different. The Holocene climate in the late show with dry - Cold - warm three stages, which may be S/V, C/V phase change reasons. Furthermore, between song and Jin (800A B.P.) south of the nomadic peoples of Mongolia the Yellow River River Basin grassland destruction may cause 0~-20cm interval of angiosperms was significantly reduced, the gymnosperm concentration input. In addition, the complexity of the the Yellow River river near 2000 the terrigenous plant debris coerced into the sea The variety and quantity of the 0~-75cm fluctuated significantly, resulting in a significant fluctuation in the S/V and C/V range.
3. N02 P/ (V+S) and 8 Sigma is a first attenuation correlation trend, indicating that the methyl / demethoxy degradation is the main degradation of terrigenous organic matter in the column. And (Ad/Al) V, P/ (V+S), (Ad/Al) S top-down stable fluctuation trend shows that the degradation of lignin in the sediment mainly occurred in the process of migration in the river, and was buried in after the degradation is not significant. The two conclusions and N02 the reduction of burial environment coincide.
4. according to the time speculated that the N02 column in 8 Sigma in -100cm, -160cm, -180cm, near -225cm increased significantly, 3.2~3.1,4.4~4.2,5.0~4.7 and 5.9~5.5ka B.P. that enhance its corresponding to the East Asian winter monsoon, especially near -160cm, 8 Sigma has repeatedly increased, this study shows that the "4.2ka" event times enhancement of the East Asian Winter Monsoon characteristics repeatedly coincide. Along with the enhancement of the East Asian winter monsoon intensity increase, the Yellow Sea coast flow can carry terrigenous organic matter more, resulting in the increase of terrigenous materials to sea transport, this is one of the 8 sigma way in response to environmental change. Secondly, the pillars decreased gradually from the bottom and top Pon/P in general. Time points from strong to weak and variable nodes and the East Asian winter monsoon is very consistent with (6.0~4.2~1.8~0ka B.P.), showed that Pon/P can also change the response intensity of winter monsoon in East Asia to a certain extent.

【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

【参考文献】