【作者】 方建勇；

【导师】 陈坚；

【作者基本信息】 国家海洋局第三海洋研究所 ， 环境科学， 2008， 硕士

【摘要】 本文以厦门湾海底沉积物的时空分布特征及其与沉积环境的相互作用为研究目标,通过分析研究区沉积物的粒度、矿物和年代学参数探讨其时空分布特征及其与沉积环境的相互关系。依据沉积动力学方法,探讨了研究区颗粒物的物质来源和运移特征。运用粒度、矿物学、年代学和沉积动力学手段,对研究区表层沉积物进行了沉积物类型、矿物组成、运移趋势、沉积物物质来源等多种分析。结合矿物学、沉积学的方法和210Pb测年数据,对研究区柱状沉积物样品进行了综合分析。在此基础上进一步探讨了研究区沉积物的物质来源及其与海洋沉积环境的相互作用。在沉积物平面分布特征研究方面,获得了如下结果:1)表层沉积物类型有8种,表层沉积物粒度资料的分析揭示了厦门湾各海区沉积物颗粒的粗细、水动力条件以及沉积环境等;2)表层沉积物中发现有50种矿物,其中重矿物38种,轻矿物12种。重矿物以磁铁矿、钛铁矿、普通角闪石、绿帘石、褐铁矿、赤铁矿、片状矿物、锆石为主。根据重矿物分布特征,研究区可分为7个主要矿物组合区,18个亚区;3)应用GSTA模型对表层沉积物运移趋势分析结果显示:来自九龙江径流的物质绝大部分通过厦门外港往外海输运,一部分进入料罗湾沉积,少部分在涨潮流的作用下进入厦门西港;厦门西港北部的物质往西港南部和高集海堤涵洞口方向输运;同安湾沉积物自湾顶向湾内输运,整体有向高集海堤方向和湾口输运的趋势;厦门岛东部海域沉积物向北输运,翔安南部海域则一部分向同安湾口和澳头岸边输移,一部分向大、小嶝岛方向输运。围头湾沉积物有从湾外往湾内输运的趋势,并向岸扩散;料罗湾沉积物质由东南往西北方向输运,具有逆时针旋转的趋势。在沉积物垂向(时间尺度上)分布特征方面,获得了如下结果:1)柱状沉积物粒度特征反映了各海区间沉积环境的差异及变化,再现了各海区受自然和人为活动的影响。2)研究区柱状沉积物优势矿物组合为金属矿物组合,金属矿物中以磁铁矿、钛铁矿含量为主,其自身抗风化能力较强。3)各海区柱样沉积速率的计算结果表明,厦门湾近年来沉积速率有增大的趋势。综合沉积物平面和垂向分布特征,有关研究区物质来源和物质运移及沉积环境方面,获得如下结果:1)厦门湾沉积物的主要物质来源为九龙江径流和厦门湾周缘基岩风化侵蚀产物以及部分来自浙闽沿岸流的台湾海峡物质;2)泥沙入海和周边岩性控制厦门湾的矿物组合,影响研究区沉积物重矿物分布的因素有矿物自身抗风化能力、水动力、物源及沉积环境因素等,研究区沉积速率普遍增大的原因来自于人类活动的结果。3)影响沉积环境的因素主要是水动力和地形地貌。更多还原

【Abstract】 The present study investigated spatial and temporal distribution characteristics of sediment in Xiamen bay, and the interaction with depositional environment through analyzing grain size, mineral, the parameter of chronology. We also discuss the source and transport characteristics of the grain in the target area according to the sediment dynamics technique.We analyzed the types, mineral component, transport trend and sediment source through grain size, mineralogy, chronology and sediment dynamics . Sediment cores were analyzed comprehensively in combination with the data of 210Pb, mineralogy and chronology,. Source of sediment and it interaction with the depositional environment of sea was discussed on the basis of these data.We obtained the following results on the horizontal distribution of sediment: 1)There are eight types of surface sediment. Their granularity revealed the thickness, hydrodynamic and environment of sediment.2)Fifty kinds of minerals were found in surface sediment, including 38 kinds of heavy minerals and 12 kinds of light minerals. The dominant are magnetite, ilmenite, hornblende, epidote, limonite, hematite, isinglass, zircon et al. Seven mineral assemblage zones and eightee sub-zones were classified according to the distribution characteristics of heavy minerals.3) The analysis of the trend of surface sediment transport by GSTA model revealed that the substance from Jiulong river was mostly transited to the sea through Xiamen outer harbor, some went into LiaoLuo Bay, and a few went into Xiamen west harbor during high tide. The substance in the north of Xiamen west harbor transited to the south and the mouth of culvert of Gaoqi-Jimei Gauseway; They transited from the top to the interior in the TongAn Bay, with a general trend toward Gaoqi-Jimei Gauseway and the mouth of the TongAn Bay. The substance in the east of Xiamen island moved to the north, those in the south of XiangAn transited to the mouth of TongAn bay and Aotou, or to the DaDeng and XiaoDeng island. The sediment substance in WeiTou Bay tended to move from the outside to the inside, and diffused along the coast. The substance in Liaoluo bay transported from southeast to northwest in the anticlockwise direction.We acquired the result of vertical (temporal) distribution characteristics of sediments:1)The result of grain size analysis of core sediment indicated the difference and transformation, reappearanced the effects by nature and human activity in every sea area.2)The dominant mineral assemblage zones are metal minerals in core sediment. The metal minerals mostly consisted of magnetite and ilmenite which have good weatherproof ability.3) Sedimentary rate in Xiamen sea area has increased in past years. We acquired the result about the source, substance transport and depositional environment on the basis of horizontal and vertical distribution characteristics of sediment.1)The depositional substance in Xiamen bay was mostly from Jiulong River and efflorescent rock nearby Xiamen Bay. Some of them come from Fujian and Zhejiang longshore currents.2)Sand from land and the lithology nearby Xiamen Bay control the mineral assemblage zones. The factors that affect heavy mineral distribution are the weatherproof ability of mineral, water power, source, depositional environment and so on. Deposit velocity increased due to human activity.3)The factor that effect depositional environment are mostly water power and topographty, and physiognomy.更多还原