渤海莱州湾南岸潍河-弥河三角洲:沉积序列和沉积格架

潍河-弥河三角洲是一个由多条河流共同塑造的三角洲。前三角洲黏土质粉砂是各河流共同贡献的结果;每条河口之外形成各自的三角洲前缘,主要由极细砂组成;河口间湾沉积物是两条相邻河流共同塑造的,主要为黏土质粉砂。由于河口位置的侧向摆动,三角洲前缘极细砂和河口间湾黏土质粉砂会交替出现。7000a B. P. 以来向海进积20~55km,在海岸附近三角州沉积物厚度超过20m。     

黄河三角洲沉积物的自然固结压实过程及其影响

对黄河三角洲及下伏沉积物的压实量和压实过程及其引起的地面沉降进行了分析研究。分析认为,在厚度为15 m的新淤积的黄河三角洲沉积重压下,前三角洲粘土和下伏海相粘土总固结量可达约1.35 m,海湾或烂泥湾及前三角洲和海相粘土总压缩量为1.48 m。这些粘土层在亚三角洲建设时期就开始受压固结,但是在亚三角洲废弃后,仍要经过几十年自然固结才会基本完成。除去前10年的固结量,前三角洲粘土与下伏海相粘土叠加形成的14 m厚粘土在随后的27年内可能会压缩50 cm;而海湾或烂泥湾及前三角洲和海相粘土叠加成的20 m厚粘土在50年内可能会压缩86 cm,两者的年平均压缩速率都超过17 mm/a。固结量和速率与上负沉积物重量成正比,而亚三角洲沉积厚度从沉积中心向外围逐渐减少,所以下伏粘土固结量和速率也向周围逐渐降低。但从亚三角洲沉积厚度分布情况看,在大范围内,下伏粘土固结引起的地面沉降在几十年内都将比较明显,从而可能加重三角洲地区风暴潮和海岸侵蚀灾害,降低已有灾害防治工程的作用。     

近代黄河三角洲的沉积特征*

本文论述了近代黄河三角洲沉积物的数量特征、粒度特征及共分布、结构与构造特征,认为:1.各期亚三角洲的淤积厚度、速率和陆地淤积率都与亚三角洲的建造历时及废止方式有关,淤积厚度有共最大限度;2.沉积颗粒均细于0.25mm级,粉砂粘土占优势,无推移质段。Mz(φ)值与δ_f成正比,与Kg成反比;3.沉积构造与沉积水动力及颗粒大小有关,沉积物的分布与结构反映了三角洲建造的基本特征。     

黄河河口泥沙扩散规律分析——以钓口河流路为例

分析黄河口钓口河亚三角洲不同时期泥沙沉积速率和水沙条件变化,发现来沙输沙率是影响黄河三角洲沉积速率的主要因素,随输沙率增加三角洲泥沙沉积速率增大.来水流量和来沙粒度组成变化对沉积速率的影响不明显.还发现来水含沙量与三角洲泥沙淤积占来沙的比例(沉积比)之间为双值关系,在某一含沙量时沉积比达最大值.对比显示,在河口河道畅通,沙嘴突出时期,三角洲泥沙沉积比反而比河口改道初期大,意味着集中水流入海可能降低海流带走泥沙的比例.另外,根据前三角洲的地形测量资料分析发现,进入远海的泥沙随距离增加呈指数递减.对黄河口这些独特的泥沙扩散规律发生机理进行了深入分析.     

长江三角洲前缘近十余年的冲淤演变及工程影响研究

根据1994-2008年国家专业部门测量的长江口口门区水下地形图及相关数据资料,分析了长江河口三角洲近十余年的冲淤过程:1)在长江来沙显著减少的背景下,三角洲出现了由淤到冲的转换,1994-2000年、2000-2008年,长江口门研究区(1 500 km2)净淤积量分别为7.25亿m3(1.21亿m3/a)和-1.23亿m3(-0.15亿m3/a),冲淤转换的临界输沙率约为2.97亿t(大通站).冲淤转换的时间大约发生在2000-2002年;2)三峡水库蓄水加速了长江来沙的减少,近几年入海泥沙减少和河口口门区出现的冲刷有一半左右归因于三峡工程的运行;3)2000年以来,河口口门外水深超过7 m的大部分区域处于蚀退,尤以10～20m区域侵蚀最为强烈,但0m以上潮间带滩地较前一时段淤积加强,1994-2008年,四大滩地的面积平均增长了约34.2％.研究结果表明:入海泥沙减少是长江三角洲由淤积转为侵蚀的主要原因,三峡水库蓄水加剧了长江入海泥沙的减少及三角洲的侵蚀,河口滩地的逆势淤积是近年一系列的河口重大工程影响的结果.     

近期长江北支口门圆陀角附近潮滩地貌动态变化

圆陀角位于长江北支岸线与江苏海岸线的交会处,独特的互花米草潮滩、淤泥质光滩环境和复杂的河海沉积动力,决定了潮滩地貌对海洋环境变化的响应具有敏感性。由于大规模的围垦,圆陀角附近过去40年来海岸线向东推进了6km。根据2006年以来多次的野外调查和室内粒度与钻孔岩芯的¹³⁷Cs分析, 2006年以来圆陀角附近潮滩淤积明显加强,由¹³⁷Cs时标估算的互花米草滩多年平均沉积速率为2.3cm/a, 2006~2008年观测到的互花米草滩淤积速率>4cm/a,粉砂淤泥质光滩的淤积速率更高;圆陀角风景区内互花米草滩前缘陡坎在风暴潮影响下侵蚀后退,并因粉砂淤泥质光滩的快速淤长而消亡,圆陀角附近潮滩地貌动态是对人类围垦活动、风暴潮与潮汐海洋动力的综合响应,互花米草与光滩快速淤积是近期圆陀角附近潮滩地貌演化的主要特点。     

渤海菜州湾南岸潍河-弥河三角洲：沉积序列和沉积格架

潍河-弥河三角洲是一个由多条河流共同塑造的三角洲。前三角洲黏土质粉砂是各河流共同贡献的结果;每条河口之外形成各自的三角洲前缘,主要由极细砂组成;河口间湾沉积物是两条相邻河流共同塑造的,主要为黏土质粉砂。由于河口位置的侧向摆动,三角洲前缘极细砂和河口问湾黏土质粉砂会交替出现。7000aB．P．以来向海进积20～55km,在海岸附近三角州沉积物厚度超过20m。     

磨刀门河口沉积物粒度特征与沉积环境

磨刀门河口的发育深受地质构造和动力条件的制约，在河流和海洋的相互作用下，形成了复杂的沉积特征。根据磨刀门河口表层沉积物的粒度分析结果，运用数学地质方法对粒度参数进行多元统计对应分析，并在此基础上结合地貌和动力条件，分析河口的沉积物粒度特征及其动力沉积环境。结果表明，河口表层沉积物主要有粉砂质粘土、粘土质粉砂、极细砂、细砂等类型；沉积环境可划分为河口主槽沉积环境、涨潮流沉积环境、浅滩沉积环境、拦门沙坝沉积环境及河口前缘沉积环境。     

长江河口悬浮泥沙的混合过程

根据准同步观测的悬浮泥沙及表层沉积物粒度、流速、含沙量资料, 分析了长江口及临近海域悬浮泥沙在河口的混合过程。长江河口-陆架系统悬浮泥沙中值粒径呈现“细-粗-细”的变化规律, 河口上段悬浮泥沙中值粒径为8.9 μm, 拦门沙海域为10.5 μm, 陆架区为4.5 μm, 北支为9.9 μm, 杭州湾口为5.6 μm, 泥沙类型为粘土质粉砂。河口上段和陆架区悬浮泥沙与表层沉积物的垂向混合作用较弱, 拦门沙区域二者发生强烈的混合和交换, 悬浮泥沙在由长江河口向陆架系统输移过程中仅有表层泥沙保留了流域输入的泥沙粒度特征。长江口悬浮泥沙中值粒径与含沙量呈良好的正相关关系, 水流的剪切作用是引起拦门沙海域泥沙再悬浮、近底高含沙量和悬浮泥沙粒径增加的主要原因, 悬浮泥沙粒径和含沙量的增加主要由粉砂组分的增加引起。2007 年长江河口区范围内悬浮泥沙中值粒径比2003 年普遍减小11％, 含沙量比2003 年减小22%, 河口上段含沙量对流域来沙减少的响应最为敏感, 而拦门沙区的泥沙粒径对流域来沙减少的响应最敏感。在长江流域来沙量减少的背景下, 河口拦门沙区域仍能维持较高的含沙量, 主要缘于河口系统内部的供沙     

黄河三角洲潮滩沉积物磁性特征与沉积环境分析

环境磁学方法作为沉积记录研究的重要手段,已在黄土、湖泊和陆架沉积物中得到广泛应用,但将此方法应用于潮滩沉积环境的研究并不多。因此,通过测量黄河三角洲潮滩YDZ1柱样沉积物磁学和粒度参数,结合AMS14C测年数据,对末次冰盛期后黄河三角洲潮滩沉积物磁性特征与沉积环境进行分析。结果表明:以假单畴(PSD)~多畴(MD)晶粒为主的亚铁磁性矿物主导了潮滩沉积物的磁性特征,磁学参数中的χARM,χARM/SIRM和χARM/χ可视为粘土(4μm)或细粒级组分(32μm)含量的代用指标。潮滩沉积相序自上而下为泛滥平原相、河流相、三角洲前缘相、浅海相、潮坪相和河流相,沉积环境表现为强(陆相)、弱(海相)、强(陆相)的演变过程。     

Recent geomorphic changes in the Liaohe Estuary

This paper mainly analyzes the geomorphological changes of the tidal deposition in the Liaohe Estuary based on the multi-year bathymetric charts in 1990, 1996, 2002 and 2005 and Landsat TM images in 1987, 1994, 2002 and 2005. Evolution of the tidal depositional system during the past 20 years in the Liaohe River was studied on the basis of 50 boreholes drilling and 30 km shallow stratigraphic exploration from 2002 to 2005. The main tidal depositional body of the modern Liaohe River delta is located in the Shuangtaizihe Estuary. The stratum within the depth of 10 m includes tidal bank facies, tidal channel facies and neritic facies with paleo-delta facies underlying them. The sediments of tidal bank facies are mainly composed of sand and silt with siltation load and suspended load of about 50% respectively in proportion. The sediment of tidal channel facies and neritic facies is composed of clayey silt and silty clay which belongs to suspended load. The study area was a small bay between the old Daliaohe River, the old Dalinghe River and the Raoyanghe River complex delta since the Holocene to 1896. Many tidal banks formed and expanded rapidly after the Shuangtaizihe River was excavated by labor in 1896. The runoff and sediment discharge have decreased since the construction of brake at the Shuangtaizihe River in 1958.The Shuangtaizihe Estuary is in the state of deposition as a whole whose tidal bank is increasing and expanding southward, westward and northward. The maximum expansion speed is 87 to 683 m/a and the mean depositional rate is 0.189 m/a. Erosion occurred in some part of tidal bank with average erosional rate of 0.122 m/a. The tidal channel was filled up with sediment at a migration speed of 48–200 m/a. Geomorphologic changes have happened under the combined influences of runoff, ocean dynamics and human activities. The main source of sediment changes from river sediment to sediment driven by tidal current and longshore current.     

辽河三角洲地貌演化(英文)

This paper mainly analyzes the geomorphological changes of the tidal deposition in the Liaohe Estuary based on the multi-year bathymetric charts in 1990, 1996, 2002 and 2005 and Landsat TM images in 1987, 1994, 2002 and 2005. Evolution of the tidal depositional system during the past 20 years in the Liaohe River was studied on the basis of 50 boreholes drilling and 30 km shallow stratigraphic exploration from 2002 to 2005. The main tidal depositional body of the modern Liaohe River delta is located in the Shuangtaizihe Estuary. The stratum within the depth of 10 m includes tidal bank facies, tidal channel facies and neritic facies with paleo-delta facies underlying them. The sediments of tidal bank facies are mainly composed of sand and silt with siltation load and suspended load of about 50% respectively in proportion. The sediment of tidal channel facies and neritic facies is composed of clayey silt and silty clay which belongs to suspended load. The study area was a small bay between the old Daliaohe River, the old Dalinghe River and the Raoyanghe River complex delta since the Holocene to 1896. Many tidal banks formed and expanded rapidly after the Shuangtaizihe River was excavated by labor in 1896. The runoff and sediment discharge have decreased since the construction of brake at the Shuangtaizihe River in 1958.The Shuangtaizihe Estuary is in the state of deposition as a whole whose tidal bank is increasing and expanding southward, westward and northward. The maximum expansion speed is 87 to 683 m/a and the mean depositional rate is 0.189 m/a. Erosion occurred in some part of tidal bank with average erosional rate of 0.122 m/a. The tidal channel was filled up with sediment at a migration speed of 48–200 m/a. Geomorphologic changes have happened under the combined influences of runoff, ocean dynamics and human activities. The main source of sediment changes from river sediment to sediment driven by tidal current and longshore current.     

南黄海辐射沙脊群里磕脚11DT02孔沉积相分析及环境演化

11DT02孔位于南黄海辐射沙脊群东北部里磕脚沙脊南坡,通过沉积相分析、粒度统计,结合年代地层数据,重建晚更新世以来里磕脚沙脊的长周期环境演化,分析沙脊成因、厘定沙脊发育年代。研究表明:里磕脚沙脊从下至上由潮滩相、硬黏土相、潮滩相和潮流沙脊相组成。潮流沙脊和潮滩由粉砂、细砂和少量黏土组成,两者均成正偏态分布。潮流沙脊和潮滩在概率累积曲线上分别表现为三段式和四段式分布,以跳跃次总体为主,并呈双跳跃特点。研究区晚更新世经历海平面下降发育潮滩环境,到完全暴露形成标志性的“硬黏土”层;全新世初期经历海侵,研究区复又开始潮滩沉积,随后被海水完全淹没,潮流作用渐强,改造下伏潮滩和“硬黏土”,逐渐堆积成高差最大达30 m的脊槽地形。     

浙南淤泥质海岸冲淤变化和泥沙运动

本文研究了浙南北起瓯江口,南至平阳咀淤泥质海岸的冲淤演变过程,指出,岸滩每年以10—20米的速度向海淤涨。为该地区海涂的开发提供了依据。     

Extraction and spatiotemporal evolution analysis of tidal flats in the Bohai Rim during 1984-2019 based on remote sensing

Tidal flats, a precious resource that provides ecological services and land space for coastal zones, are facing threats from human activities and climate change. In this study, a robust decision tree for tidal flat extraction was developed to analyse spatiotemporal variations in the Bohai Rim region during 1984-2019 based on 9539 Landsat TM/OLI surface reflection images and the Google Earth Engine (GEE) cloud platform. The area of tidal flats significantly fluctuated downwards from 3551.22 to 1712.36 km² in the Bohai Rim region during 1984-2019, and 51.31% of tidal flats were distributed near the Yellow River Delta and Liaohe River Delta during 2017-2019. There occurred a drastic spatial transition of tidal flats with coastline migration towards the ocean. Low-stability tidal flats were mainly distributed in reclamation regions, deltas, and bays near the estuary during 1984-2019. The main factors of tidal flat evolution in the Bohai Rim region included the direct impact of land cover changes in reclamation regions, the continuous impact of a weakening sediment supply, and the potential impact of a deteriorating sediment storage capability. The extraction process and maps herein could provide a reference for the sustainable development and conservation of coastal resources.     

黄河口拦门沙的形成和演变

从河海双向动力平衡角度，阐明了泥沙在滞流点附近沉积，以及滞流点位置变动，拦门沙发育和演变的特征，提出了河口海岸７．５ｍ水深为冲淤分界线及涨落潮期间拦门沙的冲淤分布，其结论对黄河口拦门沙治理具有现实意义。     

贝壳堤的形成与风暴沉积——以广东台山长湾贝壳堤为例

台山市西南部沿海有一条由典型风暴潮沉积堆积形成,出露高度远高于现代风暴潮增水面的贝壳堤.根据贝壳堤出露的横向与纵向剖面以及横剖面上的3个钻孔的形成年代、沉积特征的分析表明风暴潮在贝壳堤发育过程中的不同阶段具有不同的侵蚀与堆积作用;贝壳堤风暴沉积也具有丘状层理、切割充填结构等典型的风暴沉积特征,但贝壳堤风暴沉积与浅海陆架上的风暴沉积在沉积过程、堆积层位、保存条件等方面具有明显的差异.长湾贝壳堤是由多次风暴加积而成,形成贝壳堤的风暴增水高度接近或高于历史最高记录.形成贝壳堤的风暴沉积堆积于平均海面之上,所以增     

下辽河平原和辽东半岛海岸带晚更新世以来的海侵

本文根据钻孔资料、¹⁴C测年数据、微体古生物及孢粉组合特征,讨论了研究区晚更新世以来海侵的次数、规模、时间以及岸线变化。     

Evaluation and Hotspots Identification of Shallow Groundwater Contamination Risk in the Lower Reaches of the Liaohe River Plain

As a prerequisite for groundwater protection and contamination control, evaluation of groundwater contamination risk was the extension of groundwater vulnerability assessment. Based on disaster theory and using shallow groundwater of the lower reaches of Liaohe River Plain as the study area, we built an evaluation index system and a contamination index model for groundwater contamination risks from the perspectives of intrinsic vulnerability, external stresses, and functional value. We used data acquisition technology (remote sensing) and spatial analysis technology (GIS) to calculate the value of groundwater contamination risks. The spatial distribution of hotspots was obtained by calculating G index. Results show that groundwater contamination is above a mid-level risk in most of the study area. Areas with extreme high risk account for 37.86%, areas with high risk 32.47%, areas with moderate risk 12.07%, areas with light risk 3.17%, and areas with slight risk 14.43%. Hotspots areas are mainly located in central Shenyang City, northwest of Xinmin City, Beizhen City and Liaozhong County. Coldspots are mainly in Panjin City, Yingkou City, Dashiqiao City, Dawa County and Panshan County. The results reflect the spatial distribution and mechanism of groundwater contamination risk in the study area and provide relative references for land use planning and groundwater resource protection in the lower reaches of the Liaohe River Plain.     

人类活动对磨刀门水道河床地形和潮汐动力的影响

基于实测地形和水文资料,探讨人类活动对近期磨刀门水道河床地形和枯季潮汐动力变化的影响。研究结果表明:(1) 磨刀门上游河段大规模河床挖沙引起河床高程显著降低,水深增大,河槽容积增加,底坡降减小;口门围垦整治导致磨刀门口门区水域面积变小,入海口门向海延伸,入海水道增深。(2) 磨刀门水道河床地形变化引起枯季潮汐动力发生变化:上游河段低潮位降低,潮差增大,进潮量增加,潮汐动力明显增强;口门区潮差减小,横洲水道潮能汇聚,水位壅高;水面坡降减小,潮波传播速度增加,咸水界上移。