渤海湾西岸现代岸线钻孔记录的全新世沉积环境与相对海面变化

发布时间：2018-03-09 10:58

本文选题：渤海湾西岸现代岸线　切入点：全新世　出处：《吉林大学学报(地球科学版)》2016年02期 　论文类型：期刊论文

【摘要】：以渤海湾西岸现代岸线附近的NP3、CH110和BT113三个钻孔全新世岩心为研究对象,采用沉积岩石学、AMS 14 C(accelerator mass spectrometry 14 C,加速器质谱14 C)测年、微体生物聚类分析等方法精细判别沉积相,重建渤海湾西岸全新世沉积演化历史,并利用微体生物组合分带对水深变化的指示,定量讨论全新世相对海面变化。结果表明:渤海湾西岸全新世受海陆交互作用影响,经历了沼泽—潮滩—浅海—前三角洲—三角洲前缘—三角洲平原环境的演化过程。全新世初始阶段,研究区中部和北部发育沼泽环境,南部未见沉积,与上更新统河流相沉积呈不整合接触。全新世早期,研究区潮滩环境发育。潮滩层厚度约1m,历时数百至1千余年。至7 000cal BP前后水深增大,研究区进入浅海环境。约6 000cal BP,沿岸南北两端先后进入三角洲过渡环境,中部三角洲环境约开始于1 500cal BP。渤海湾西岸地区全新世的环境演化同时记录了该地区的相对海面变化:约10 000cal BP前后,渤海湾相对海平面已接近21.3~20.4m。约8 000cal BP,相对海平面介于18.6~17.0m。约6 000cal BP时相对海平面低于6.8m,5 000~1 000cal BP,相对海平面高于-2.5 m,1 000~800cal BP,相对海平面介于-1.3~-0.4 m。8 000~5 000cal BP时,相对海面上升约15.0m,上升速率达5m/1ka。
[Abstract]:Three Holocene cores, NP3CZ CH110 and BT113, near the modern shoreline in the west coast of Bohai Bay, were studied. Sedimentary facies were carefully identified by means of sedimentary petrology, AMS14 CX accelerator mass spectrometry 14C, accelerator mass spectrometry 14C, microbiological cluster analysis, etc. The sedimentary evolution history of Holocene in the West Bank of Bohai Bay was reconstructed, and the relative sea level variation of Holocene was quantitatively discussed by using the indication of microbiological assemblage zoning to the variation of water depth. The results show that the Holocene in the west coast of Bohai Bay was influenced by the interaction of sea and land. During the initial period of Holocene, the swamp environment was developed in the middle and north of the study area, but no sediment was found in the south of the study area. In the early Holocene, the tidal flat environment developed in the study area. The tidal flat layer was about 1 m thick and lasted for several hundred to more than 1,000 years. The water depth increased before and after 7 000 cal BP. The study area entered the shallow sea environment. About 6 000 cal BP, the two ends of the coastal north and south successively entered the delta transition environment. The central delta environment began to evolve in the Holocene in the west coast of Bohai Bay, and recorded the relative sea level change around 10 000 cal BP. The relative sea level of the Bohai Bay is close to 21.3kW 20.4m. about 8,000 cal BP.When the relative sea level is between 18.6m and 17.0m. about 6,000 cal BP, the relative sea level is lower than 6.8mb / L 5000 cal BP, and the relative sea level is higher than -2.5 mtl 1000 cal BPand when the relative sea level is between -1.3- 0.4 m.8 000kcal / BP, and the relative sea level is within -1.3- 0.4 m.8 000kcal / BP, respectively. Relative to the sea, it rises about 15.0m, rising at a rate of 5m / 1ka.
【作者单位】：中国地质调查局天津地质调查中心;中国地质调查局泥质海岸带地质环境重点实验室;
【基金】：国家自然科学基金项目(41372173,41476074) 中国地质调查局项目(1212011120169,12120113005800)~~
【分类号】：P736.2

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