沉积物干容重分析及其沉积学意义:以东海内陆架海区为例

干容重是沉积学研究中用于计算物质通量的一个重要参量,对于正确认识沉积物的收支平衡、源汇通量以及地貌演化等问题具有重要意义。然而,干容重的分析流程和计算方法仍然缺乏统一的规范,导致干容重的取值不尽合理,影响了沉积学研究的定量化和精准度,这个问题需要引起足够的重视。本文选取了东海内陆架的表层沉积物和柱状沉积物,运用实验测试和间接公式计算两种方法获得了沉积物的干容重,对比分析了两种方法的精准度。研究发现,东海内陆架的细颗粒沉积物的干容重的数值范围是1.1—1.5g/cm³;影响沉积物干容重的主要因素是沉积物的成分与粒度,前者通过颗粒态物质的密度起作用,后者通过孔隙度来影响。建议:干容重的分析测试工作应在采样后尽快完成;运用干容重进行沉积通量计算时,应根据沉积物的平均粒度和孔隙度的空间变化选择合适的数值,以获得更加合理的结果。     

百年尺度东海内陆架风暴事件重建:器测记录与沉积记录耦合

未来全球变化可能带来极端事件的强度增加、频度提高,加之海面上升加快,给海岸带防灾减灾工作带来更新防护标准的课题。由于台风的器测记录时间较短,需要从其他载体寻找替代指标以延长台风记录的时间跨度,这样才能更好地估计极端事件的强度一频率关系。陆架泥质区的风暴事件沉积记录和历史文献中的有关灾害记录,是拓展台风记录的两个方向。本文试图通过台风观测记录与沉积记录的耦合,重建百年尺度东海内陆架泥质区的风暴事件沉积记录,并与气象灾害记载的台风暴潮成灾事件相印证,以期探讨陆架泥对台风事件的保存潜力,及其可能反映的台风信息(如路径和强度)。2018年在浙江温岭近海采集了2 m长的柱样沉积物(J1),通过多指标(粒径分布、D₉₀、Zr/Fe、Sr/Al、Ca)综合识别出台风沉积事件;采用放射性同位素²¹⁰Pb定年法确定沉积物的年代序列,将识别的台风沉积记录与器测台风记录通过时间标尺进行耦合分析。结果显示,J1的沉积速率约为1.1 cm/a,年代跨度大约是1836年至2018年;整根柱样共识别出25次台风沉积事件,其中气象观测时期(1950-2018年)有10次台风...     

高能波控陆架的风暴沉积和风暴层序——以澳大利亚东南部陆架为例

根据浅层地震和钻孔资科,将澳大利亚东南部研究地区高能波控陆架风暴沉积分为直立风暴层、叠瓦状风暴层、无序风暴层、水平风暴层和纹层状风暴层等五类。各类风暴层及风暴层与非风暴层组合而成悬移风暴层序、悬移-推移混合风暴层序和推移风暴层序三大类。中陆架风暴沉积与现今近岸和水下岸坡相似,岩性、岩相和古生物属海岸带,风暴沉积厚,底板埋深大,组成物质粗。推断中陆架风暴沉积当形成于冰后期海侵、该地带处在近岸带和水下岸坡环境时,此时海面上升速度可能减缓,或趋近于零,甚至可能有短时间的下降。     

强潮海滩响应威马逊台风作用动力沉积过程研究——以北海银滩为例

研究台风影响下的海滩沉积过程不仅可加深极端海况下的海滩冲淤变化理解,而且有利于海滩资源的保护与海岸工程保护。以强潮海滩——北海银滩为例,通过采集北部湾海区1409号威马逊超强台风作用前后的沉积物、剖面高程及水文资料,探讨强潮海滩的动力沉积过程。结果表明:1)台风作用前后的海滩沙丘-滩肩-沙坝体系的地貌状态基本不变,其中沉积物组分均为砂,细砂、极细砂和中砂三组分平均含量占所有组分的95%以上;与台风作用前比较,台风后的地貌在维持先前形态的条件下,发生局部侵蚀和后退,沉积物相对变粗且细砂含量增加了10%。2)台风作用后后滨沙丘侵蚀,且沉积物滚动组分增加;冲流带和滩肩前缘沉积物的搬运由双跳跃转为单一的跳跃形式。3)台风作用前后的海滩沉积物主要变化过程可由两个模态表征,其中主要模式反映了台风作用前后的海滩以细砂为主的动力沉积变化特征,该模式受控于区域波浪和潮汐的长期耦合作用,并以波浪为主导因素。台风作用前的次要模式反映潮汐作用控制下的海滩沉积横向振荡特征;台风作用后的次要模式表征了台风影响下的海滩横向沉积物偏粗、冲流带-低潮带振荡及其沉积分异过程。     

基于生态化人工海岸建设的理论研究与应用 ——以天津永定新河口综合整治修复工程为例

分析生态文明背景下围填海区域人工海岸建设存在的问题,结合淤泥质人工海岸空间特点,总结提出了生态岸线整治修复技术、仿自然化处理设计、景观构建适宜性、人工海岸生态系统等生态化建设基础理论,并以天津永定新河口综合整治修复工程为例,重点阐述了人工海岸生态化建设过程中生态系统和景观构建的方法要点和具体思路.结果表明:在人工海岸生...     

山东半岛东部南北岸典型砂质海岸沉积、地貌的横向差异及成因分析———以海阳万米海滩岸段和威海国际海水浴场岸段为例

根据2011年在海阳万米海滩岸段与威海国际海水浴场岸段调查获得的夏、冬两季海岸实测地形剖面与沉积物粒度数据,并收集相关水文资料,对南北两海岸地貌与沉积差异性进行分析,探讨了半岛东部南北岸典型砂质海岸动力环境的差异。研究结果表明,南部海岸宽广平缓,发育滩脊、滩肩、沙波纹等地貌,沉积物在水下岸坡上段以中粗砂、中细砂为主,水下岸坡以下段以粉砂、黏土质粉砂为主;北部海岸地形陡,发育滩肩陡坎、水下沙坝等地貌,沉积物以砾质砂为主。导致这些差异的动力为风、波浪、潮汐及沿岸流堆积。     

基于多核学习遥感解译的水边线提取及海岸侵蚀风险评估方法研究与应用——以大蒲河-滦河岸段为例

为了对典型海岸带的侵蚀风险程度进行量化统计与评估,采用卫星遥感技术对目标岸段开展动态监测,以多核学习技术进行图像分类及岸线提取,基于水边线逐年位置变化提出一种海岸侵蚀风险评估方法,并以大蒲河-滦河岸段为例进行了应用,得出了该岸段所处的侵蚀风险级别,为下一步海岸带的保护与修复提供了数据支撑。     

系统聚类和主成分分析在现代沉积环境划分中的应用-以海南新村港潟湖为例

An understanding of the sedimentary environment in relation to its controlling factors is of great importance in coastal geomorphology,ecology,tourism and aquaculture studies.We attempt to deal with this issue,using a case study from the Xincun Lagoon,Hainan Island in southern China.For the study,surficial sediment samples were collected,together with hydrodynamic and bathymetric surveys,during August 2013.Numerical simulation was carried out to obtain high-spatial resolution tidal current data.The sediment samples were analyzed to derive mean grain size,sorting coefficient,skewness and kurtosis,together with the sand,silt and clay contents.The modern sedimentary environments were classified using system cluster and principal component analyses.Grain size analysis reveals that the sediments are characterized by extremely slightly sandy silty mud(ESSSM) and slightly silty sand(SSS),which are distributed in the central lagoon and near-shore shallow water areas,respectively.Mean grain size varies from 0 to 8.0Ф,with an average of 4.6Ф.The silt content is the highest,i.e.,52% on average,with the average contents of sand and clay being 43% and 5%,respectively.There exists a significant correlation between mean size and water depth,suggesting that the surficial sediments become finer with increasing water depth.Cluster analyses reveals two groups of samples.The first group is characterized by mean grain size of more than 5.5Ф,whilst the second group has mean grain size of below 3.5Ф.Further,these groups also have different correlations between mean grain size and the other grain size parameters.In terms of the tidal current,the average values of the root mean square velocity(RMSV) are 7.5 cm/s and 6.9 cm/s on springs and neaps,respectively.For the RMSVs that are higher than 4 cm/s,a significant positive correlation is found between the content of the 63–125 μm fraction and the RMSV,suggesting that the RMSV determines the variability of the very fine sand fraction.Based on system cluster and principal component analyses(PCA),the modern sedimentary environments are classified into three types according to the grain size parameters,RMSVs and water depth data.The results suggest the importance of grain size parameters and high-spatial resolution hydrodynamic data in differentiating the coastal sedimentary environments.     

GIS技术在海岛保护与利用规划中的应用——以破灶屿为例

随着全国首批开发利用的无居民海岛名录公布以来,全国海岛保护与利用规划工作迅速发展起来,文章以福建省破灶屿为例,综合考虑海岛地形、植被以及开发利用现状因素,采用GIS空间分析手段,探讨其保护与利用分区研究,并绘制海岛保护与利用规划各专题地图。     

地震多属性在少井区和无井区沉积体系分析中的应用——以渤中西环BZ3-1区块沙河街组为例

钻井和地震资料的丰富程度决定了储层预测研究精度。在多井区,利用地震属性及单井沉积相来确定平面沉积相,研究精度高;而在少井、无井区的海域,如何利用地震资料进行沉积储层研究,至今没有一个成熟的方法。渤海湾盆地渤中凹陷西环BZ3-1区钻井较少,完整钻遇到沙河街组的井则更少,以该区的沙河街组为例,基于地震多属性分析技术,结合古地貌分析,半定量确定研究区的沉积体系分布特征。通过三维可视化技术和切片技术的高精度三维沉积体系分析表明,由于三级层序发育于二级层序的不同体系域,会导致三级层序的体系域沉积体发育特征的不同。沙三段SQs3l层序发育于二级层序的低位体系域(LST),其低位体系域的扇体规模要远远大于高位体系域(HST)的扇体;SQs3m层序发育于二级层序的水进体系域(HST),其低位体系域三角洲朵体规模与高位体系域的三角洲朵体相当;SQs3u层序发育于二级层序的高位体系域,其高位体系域三角洲朵体规模远远大于低位体系域的三角洲朵体。     

Relationship between Composition of Settling Particles and Organic Carbon Flux in the Western North Pacific and the Japan Sea

Settling particles play an important role in transporting organic carbon from the surface to the deep ocean. It is known that major components of settling particles are biogenic silicates (opal), biogenic carbonate (CaCO₃), lithogenic clays and organic matter. Since each component aggregates and/or takes in organic carbon, all of these components have the ability to transport particulate organic carbon (POC) to the interior of the ocean. In this study, sediment trap experiments were carried out in four areas of the western North Pacific (including a marginal sea). Factors are proposed that correlate the composition of settling particles with POC flux. Annual mean organic carbon fluxes at 1 km depth in the western North Pacific Basin, Japan Sea, Hidaka Basin and northern Japan Trench were found to be 14.9, 18.1, 13.0 and 6.6 mg/m²/day, respectively. Organic carbon flux in the western North Pacific was greater than that in the Eastern North Pacific (7.4), the Equatorial Pacific (4.2), the Southern Ocean (5.8) and the Eastern North Atlantic (1.8). In the western North Pacific, it was calculated that 52% of POC was carried by opal particles. Opal is known to be a major component even in the Eastern North Pacific and the Southern Ocean, and the opal fluxes in these areas are similar to those in the western North Pacific. However, the organic carbon flux that was carried by opal particles (OC_opalflux) in the western North Pacific was greater than that in the Eastern North Pacific and the Southern Ocean. These results indicate that the ability of opal particles to transport POC to the deep ocean in the western North Pacific is greater than that in the other areas.     

溶解作用对南海北部沉积物捕获器碳、氮通量估算的影响

由于化学溶出、物理溶解以及胞外酶等作用,沉积物捕获器中颗粒物在锚系布放期间会发生一定程度的溶解,从而引起沉积物捕获器中碳、氮颗粒物通量的低估。本文对于1987—1988年南海北部中深层沉积物捕获器中碳、氮颗粒物的溶解作用进行了研究。溶解作用对于碳、氮通量估算的影响大致随着深度的增加而减小。总体而言,颗粒有机碳通量低估约3.8%~40.3%,平均值为26.6%。颗粒氮通量低估约4.2%~76.4%,平均值为43.7%。碳、氮颗粒物的溶出量与颗粒物通量大小关系不明显,但是样品储存时间对于碳、氮颗粒物溶解作用的影响较显著,储存时间较长的样品中颗粒物溶出量更大。     

江苏大丰潮滩悬沙级配特征及其动力响应

根据2002和2003年夏季在江苏大丰潮滩的现场观测资料,详细分析了悬沙级配的时空分布特征、影响因素及其对再悬浮、沉降和流速的响应.研究结果表明,悬沙颗粒较细,以粉砂为主,悬沙级配在潮周期内的变化模式有两种类型:一是稳定型,悬沙级配的时空(垂向和平面)变化很小;二是双峰型,悬沙级配的时空变化显著,粗细峰高度不断变化.再悬浮、沉降、涨潮时输入潮滩的悬沙和底质级配是影响悬沙级配的重要因子.再悬浮使粗颗粒悬沙的含量增加,悬沙与底质级配不断接近,沉降对悬沙级配的影响与再悬浮相反.再悬浮发生时悬沙级配对流速有明显响应.在没有再悬浮和沉降影响的情况下,潮滩不同部位、不同时间的悬沙级配趋于稳定和相同,对这种状态下的悬沙级配可称为背景悬沙级配,大丰潮滩背景悬沙级配的平均粒径为7μm.     

杭州湾枯季水沙若干特征分析

根据2014年1月及2017年2月杭州湾大、小潮水沙资料,计算了流速、含沙量、单宽潮量、单宽输沙量,进而分析了潮周期断面净潮量、净输沙量和区域冲淤分布。研究发现杭州湾涨、落潮平均流速比值整体较20世纪八九十年代增大,绝大部分区域大于1.0,涨潮流相对增强,澉浦南岸和金山北岸尤为显著。含沙量平面上分布澉浦、杭州湾南岸两个高值区(大潮大于3 kg/m³,小潮大于1.3 kg/m³)以及北岸湾口至乍浦之间的低值区(大潮小于2 kg/m³,小潮小于0.9 kg/m³),随潮汛变化显著,最大含沙量浓度通常滞后于急流时刻。各测站涨、落潮量和输沙量呈现“大涨大落”和“大进大出”的特征,造成杭州湾短时间尺度内的“大冲大淤”。大潮两涨两落金山与乍浦、乍浦与澉浦之间区域净输沙量可达几千万吨,净冲淤则在几百万吨。     

砂质海岸整治修复效果模糊综合评价研究——以营口月亮湾为例

本文采用模糊综合评价方法,从自然环境效果、景观生态效果、沙滩资源效果和社会经济效果4个方面研究构建了砂质海岸整治修复效果综合评价指标体系与评价方法,并以营口月亮湾为例进行了实证研究。结果表明:本文提出的砂质海岸整治修复效果综合评价方法涵盖内容全面,指标获取可行,评价结果明确,整体方法实用。营口月亮湾砂质海岸整治修复效果总体评价结果为优秀,综合评分为2.636 2,其中社会经济效果贡献率为30.52%,沙滩资源效果贡献率为30.17%,自然环境效果和景观生态效果贡献率分别为19.88%和19.44%。     

杭州湾口门中部水沙输运机制初探——以岱衢洋为例

根据2012年9月在杭州湾口门中部外侧海域岱衢洋主槽内获得的包括大、中、小潮的垂向流速和悬浮泥沙观测资料,利用机制分解方法计算了岱衢洋的水沙输移通量等特征,分析并讨论了各个输沙项对总输沙量的贡献,解释了杭州湾水沙进出外海的输运机制。研究结果表明:研究区域单宽涨潮量大潮为小潮的2.3倍,单宽落潮量大潮为小潮的1.6倍。从小潮到大潮的余流和单宽净输水量由向海变为向陆;单宽涨潮输沙量大潮为小潮的4.5倍,单宽落潮输沙量大潮为小潮的2.7倍。单宽输沙量表现为小潮和中潮向海,大潮向陆的特点,大潮单宽净输沙量约为小潮和中潮的2倍;在各输沙项中,平流输沙主要来自水体净输移(拉格朗日余流决定)对悬沙输移的贡献,平流输沙方向小潮向海,中潮和大潮向陆,其中大潮和小潮时平流输沙在各项中贡献率最大;潮泵输沙小潮和中潮向海,大潮输沙向陆,中潮时潮泵输沙贡献率在各项中贡献率最大;垂向净环流输沙方向均向陆,大中小潮悬沙含量的垂向的差异是导致小潮垂向净环流输沙量大,大潮输沙量小的主要原因;杭州湾中部通过岱衢洋通道与外海泥沙交换的主要形式是大进大出、反复搬运,而在一个完整的半月周期内外海泥沙净进杭州湾的量相对较小。     

渤海湾泥质区南部悬浮体夏季输运过程与机制

为了解渤海湾泥质区南部近岸及毗邻海域夏季悬浮体输运格局,分别在湾内、湾口、湾口外和黄河口外NE向剖面处设置站位,进行25 h海流、温盐连续观测及悬浮体浓度（SSC）测定。结果显示,高温淡水以羽状流的方式自近岸向渤海中部传输,高浊度悬浮体多出现在涨急和落急的流速较高时期,较高的SSC值多出现在距底5 m水深范围,其中湾内和湾口两站的底层SSC值最高,分别可达约130 和80 mg/L,黄河口外NE向剖面20 m以深海域SSC值最小,均低于40 mg/L。单宽输沙率具有潮周期性特点：湾内A1站涨潮和涨平期以向湾内近岸输沙为主,落潮和落平期以向湾外输沙为主,潮平均单宽输沙率为7.8 g·m−1·s−1,方向为280°;湾口A2站涨落潮流输沙方向相反,整体以SE向朝湾外近岸输沙为主,潮平均单宽输沙率为7.2 g·m−1·s−1,方向为328°。湾外A3站涨潮和涨平时期输沙方向基本相反,大小相当,落潮和落平时期输沙方向以偏E和偏NE向为主,潮平均单宽输沙率为4.7 g·m−1·s−1,方向为77°。黄河口SE向的两个站位涨潮时输沙偏SE向,涨平时输沙偏NW向,落潮时输沙偏NW向,落平时输沙偏N向和偏NE向,两站的潮平均单宽输沙率方向以偏N向为主,A4站的潮平均单宽输沙率为5.2 g·m−1·s−1,方向为94°,A5站潮平均单宽输沙率为7.7 g·m−1·s−1,方向为102°。潮平均单宽输沙率以拉格朗日输沙贡献最显著,在湾口泥质区南部和东南部水深15～25 m的海域,垂向净环流的影响较大,有抵消一部分拉格朗日输沙率的作用,且对潮平均单宽输沙率的影响比湾内和25 m以深海域的大,其他分量数量级较小,对潮平均单宽输沙率贡献较小。水体以混合为主,水体层化程度加强对各站位悬浮体输运均有一定的抑制作用。     

Determination and control of longshore sediment transport: A case study

The fishery harbor of Karaburun coastal village is located at the south west coast of the Black Sea. The significant waves coming from north eastern direction cause considerable rate of sediment transport along 4 km sandy beach towards the fishery harbor in the region. The resulting sediment deposition near and inside the harbor entrance prevents the boat traffic and cause a vital problem for the harbor operations. In order to determine the level and reasons of the sediment transport, the long-term observations of shoreline changes, the long-term statistical analysis of wind and wave characteristics in the region, and sediment properties have been performed. The data obtained from observations, measurements and analysis were discussed. The long-term statistics of deep water significant wave heights for each direction was discussed by comparing the results obtained from different data sources and methods. For shoreline evolution, the numerical study using one-line model was applied to describe the shoreline changes with respect to probable wave conditions. Initial shoreline was obtained from the digitized image in 1996 since there was no previous shoreline measurement of the site. The results were compared using the techniques of remote sensing obtained from sequent images using IKONOS and IRS1C/D satellites.     

A numerical study of transport dynamics and seasonal variability of the Yellow River sediment in the Bohai and Yellow seas

A sediment numerical model was embedded into a wave-tide-circulation coupled model to simulate the transport processes of the Yellow River-derived sediment considering the wave-induced vertical mixing (Bv) and the wave-current coupled bottom shear stress (BSS). Numerical results show that the main stream of the Yellow River-derived sediment moves first eastward off the northern Shandong Peninsula and then southward into the South Yellow Sea all year round. In spring, the sediment moves northeastward in the Bohai Sea. In summer, there is a northeastward branch of sediment in the Bohai Sea off the west coast of the Liaodong Peninsula, while the main part goes eastward to the Yellow Sea. The Yellow River-derived sediment transport from the Bohai Sea to the North Yellow Sea across the Bohai Strait is mainly limited to the top 10 m, and with a maximum centered at 37.9°N in summer. The transport from the North Yellow Sea to the South Yellow Sea across the transect of 37°N is mainly in the 0–30 m layer with a maximum around 123.7°E in autumn. The simulated Yellow River-discharged sediment deposits along the Shandong Peninsula and between 20 and 30 m isobaths in the Yellow Sea, which is consistent with observation. If surface waves are not considered in the model, the sediment deposits westward to the nearshore area in the South Yellow Sea. The sediment would deposit further southward in the numerical experiment results without wind influence. In the numerical experiment of no tide, there is hardly any sediment deposited on the Yellow Sea floor, while in the Bohai Sea most of the sediment is transported southward and northwestward around the river mouth instead of eastward as in the Control Run, indicating the tides play a key role in forming the deposition pattern.     

泥质潮滩的海水-地下水交换量化研究——以莱州湾南岸为例

本文目的是利用数值模拟量化研究莱州湾南岸泥质潮滩的海水-地下水交换。选取的典型剖面长约3 800 m,坡度小于1%,沿剖面选取5个监测点,观测地下水的水头和盐度,分析其随时间的变化规律。概化水文地质条件基础上,用SEAWAT-2000建立二维数值模型,模拟水流的流动并将水头模拟值和观测值进行拟合。基于良好的拟合结果,计算出海底地下水排泄(Submarine Groundwater Discharge,SGD)量为17.46 m3/m/d,海水流入量为2.71 m~3/m/d。文章最后提出了观测和模拟过程中存在的问题,需要今后进一步解决。