Gravity-Driven Listric Growth Fault and Sedimentation in the Lagoa do Peixe, Rio Grande do Sul Coastal Plain, Brazil

High frequency, high resolution GPR surveys are successfully applied to investigate near-surface stratification architecture of sedimentary units in coastal plains and to define their depositional conditions. However, low frequency GPR surveys to investigate fault-related depositional systems at greater depths are scarce. This survey was designed investigate a > 100 km long linear escarpment that controls the northwest margin of the Lagoa do Peixe, an important lagoon in Rio Grande do Sul Coastal Plain (RGSCP, Brazil). The traditional approach points that RGSCP was developed by juxtaposition of four lagoons/barrier systems as consequence of sea level changes;no deformational structure is admitted to exist before. The low frequency GPR (50 MHz, RTA antenna) and geological surveys carried out in the RGSCP showed the existence of a large, gravity-driven listric growth fault controlling the Lagoa do Peixe escarpment and hangingwall sedimentation. The radargrams in four subareas along the Lagoa do Peixe Growth Fault could be interpreted following the seismic expression of rift-related depositional systems. The radargrams enabled to distinguish three main lagoonal deposition radarfacies. The lower lagoonal radarfacies is a convex upward unit, thicker close to growth fault;the radarfacies geometry indicates that fault displacement rate surpasses the sedimentation rate, and its upper stratum is aged ~3500 l4C years BP. The second lagoonal radarfacies is a triangular wedge restricted to the lagoon depocenter, whose geometry indicates that fault displacement and the sedimentation rates kept pace. The upper lagoonal radarfacies is being deposited since 1060 ± 70 l4C years BP, under sedimentation rate higher than fault displacement rate. The results indicate that low frequency GPR surveys can help in investigating fault-related depositional systems in coastal zones. They also point to a new approach in dealing with RGSCP stratigraphy.

The impact of land use change on quality evolution of soil genetic layers on the coastal plain of south Hangzhou Bay

Land use change plays an important part in the studies of global environmental change and regional sustainable development. The change of soil quality can particularly reflect the impacts of human socio-economic activities on environment. Taking the coastal plain of south Hangzhou Bay as a study case, we analyzed the effects of land use changes on organic matter （OM）, total nitrogen （TN）, total phosphorus （TP）, available phosphorus （AP）, available potassium （AK）, total salinity （TS）, pH value in soil genetic layers, and assessed soil quality change related to different land use types from 1982 to 2003. The results show that： （1） The general change tendency of soil quality in the coastal plain of south Hangzhou Bay declined obviously in A layer and slightly rise in B （or P） layer and C （or W） layer. The contents of TP decreased generally in all soil genetic layers, but the variety difference of other soil quality indices was relatively great. （2） The change of soil quality in the areas where land use changed is far more remarkable than that with land use unchanged. The value of quality variety is A layer 〉B （or P） layer 〉C （or W） layer. （3） The changes of soil tillage, cultivation, fertilization, irrigation and drainage activities related to land use may make some soil-forming processes disappeared and bring in other new processes which will affect the soil quality and soil genetic layers directly.

Assessment of coastal vulnerability to environmental change in Jiangsu coastal plain

Assessment of coastal vulnerability to future environmental change has been emphasized in coastal nations or regions. The Jiangsu coastal plain, located to the north of the Yangtze River Delta in China, is most vulnerable to sea level rise and exacerbating coastal hazards. This paper develops the method of delimiting vulnerable scope and assessing coastal vulnerability through field observations and sampling and by applying remote sensing and GIS, which are suitable for great river delta and coastal plains with large area, relative complex micro-geomorphology and the protection of seawall. Applying this method, the coastal vulnerability of the Jiangsu coastal plain to relative sea level rise (approximately 50 cm up to the year 2050) and exacerbating storm surges have been assessed. The results show that, up to the year 2050, the Jiangsu coastal plain will probably lose 12.8 % of tidal flats (about 5.8x104 hm2) and 7.9 % of cultivated land (about 7.2x104 hm2). Meanwhile, 2.0 % of population, 3.8 % of original value of fixed assets, 3.2% of GDP (Gross Domestic Product), 40.3 % of salt industry and 5.8 % of aquiculture respectively will be affected due to coastal environmental change.

The color reflectance of marine-terrigenous deposits in LZ908 borehole in south coastal plain of the Laizhou Bay

Color measuring is characterized by high resolution,high efficiency,and low cost. The application becomes increasingly common for tracing sediment sources and climate variation. Borehole LZ908 in the south coastal plain of the Laizhou Bay in northeast China,was used,of which the top 54 m containing all marine facies was focused,to test the feasibility of colorimetry as a climate indi-cator using visible light reflectance spectra and L＊a＊b＊measurement results. The results show a good correction between lightness and calcium carbonate content in marine-terrigenous deposits;therefore,these deposits can be used as a proxy to study climate changes. Factor-analysis on the first derivative values of the raw visible light reflectance spectra produced three principal factors corresponding to goethite,organic matter,and hematite. Down hole variations in the three fac-tor scores,lightness,calcium carbonate content,and grain size were quite consistent. Moreover,high lightness and low factor scores in goethite,hematite,and organics indicated glacial regression deposits,while low lightness and high factor scores in goethite,hematite,and organics indicated interglacial transgression deposits.

Study on sea water intrusion into palaeochannels on south coastal plain of the Laizhou Bay by the Bohai Sea

The palaeochannel evolution in the study region is divided into four stages by such methods as 14C dating. Sea water intrusion through palaeochannels has been studied as a focal point. Palaeochannels are the main passageways through which the sea water intrudes at a higher speed, through many means and in a changeable dynamic state.

IMPACTS OF SEA LEVEL RISE ON MAJOR PROJECTS AND URBANDEVELOPMENT IN CHINA'S COASTAL PLAINS

Due to the dual dris oftural and man-made factors, relative sea leverise in China's coastal plains can be 2 to 3 times over the global mean dunng thefirst half of the 21st Century, it will strongly whuence the vanous coastal projectsand installations and the development of coastal dhes and towns. Research resultsshow that a 50-cm-nse in relative sea leve will cause maed decline in the functionof coastal defense and drainage projects and seriously endangur the functionalworking of the vast majority of coastal harbors. Meanwhile, it will also whuence thedevelopment of coastal dhes and towns throwi deterioratin water quality of thesource of urban water supply, increasing urban fiood risk and damagin seasidetounst resources etc.. Tianin, Shanghai and Guangzhou, the three most importancoastal dhes of China, will be Strongly affeded.

Effect of Cu and Zn on Maize (<i>Zea mays</i>L.) Yield and Nutrient Uptake in Coastal Plain Sand Derived Soils of Southeastern Nigeria

Laboratory, greenhouse and field studies were undertaken to investigate the status of Cu and Zn and to find out whether the addition of these nutrient elements in soils would increase maize grains and yield components and also, remediate their constraints in coastal plain sand derived soil of southeastern Nigeria, for optimization of maize (Zea mays L.) yields. Dry matter yields, plant concentrations, plant uptake, and maize grain yields were used to evaluate the effects of Cu and Zn levels. In both the greenhouse and field experiments, hydrated Cu and Zn sulphate fertilizers were applied to the soils in separate experiments at seven levels (0, 2, 4, 6, 8, 10 and 12 kg·ha&#45;1) for Cu and Zn respectively. The recommended N, P, and K at rates of 120, 60, 30 kg·ha&#45;1, respectively, were also used as basal application. The results showed the status of available Cu and Zn by 0.1 N HCl was found to be low in the soil. The application of Cu and Zn into the soils significantly (P < 0.05) increased maize dry matter production, concentration, uptake and grain yields. The estimated optimum rates for Cu and Zn under greenhouse environments were established at 10 kg·Cu·ha&#45;1 and 8 kg·Zn·ha&#45;1, respectively. Maximum uptake and grain yields in maize were also established at 10 kg·Cu·ha&#45;1 and 8 kg·Zn·ha&#45;1, respectively. However, maize response curve showed that for optimum grain yield, concentration for Cu was determined to be 10 mg·kg&#45;1, while for Zn it was 8 mg·kg&#45;1. The current study showed that though the soils have a severe Cu and Zn deficiency, which could be due to their strong sorption capacity and nutrients mining due to intensive and continuous cropping, maize production can still be increased considerably in this soil and other similar soils in the same agro-ecological zone within a coastal plain sand derived soil by applying Cu and Zn at rates of 10 kg·Cu·ha&#45;1 and 8 kg·Zn·ha&#45;1, respectively.

Reflections on Plain Greening in Coastal Urban Areas： A Case Study of Plain Greening in the Main Urban Area of Taizhou

The current situation,existing problems and characteristics of greening in the main urban area of Taizhou were analyzed,and the construction ideas and safeguard measures of plain greening in urban areas in the new era were put forward.

Land Suitability Evaluation for Oil Palm (<i>Elaeis guineensis</i>Jacq.) in Coastal Plains of Southwest Cameroon

Declining yields in oil palm fresh fruit bunch (FFB) have been recorded over the past years in the coastal lowlands of southwest Cameroon and current actual yields are very low (<12 t FFB ha−1•yr−1) compared to the potential yields (25 t FFB ha−1•yr−1). One of the problems limiting optimum oil palm production is lack of detailed pedological information to guide plantation establishment and management. A land suitability evaluation was carried out for some major oil palm producing areas of southwest Cameroon to identify land qualities limiting optimal production. Thirteen sites (9 with sedimentary parent materials and 4 with volcanic parent material) were evaluated using a parametric method. Results indicate that climate was not a major limiting factor for oil palm production in coastal plains of southwest Cameroon. However, soil physical characteristics (mainly clayey texture and poor drainage) and soil fertility constitute limitations to oil palm production. Specifically, limitations in cation exchange capacity (CEC), base saturation (BS), organic carbon (OC) and pH were slight to moderate while K mole fraction was the most severe and the most limiting in all the sites. The fertility limitations were more pronounced in soils derived from sedimentary parent materials where 33% had limitations caused by soil pH and OC compared to none for volcanic soils. In addition, 77.8% of sedimentary soils had limitations caused by CEC compared to 25% for volcanic soils. Considering the overall suitability, soils derived from volcanic parent materials were potentially more suitable for oil palm cultivation ((S3)—50%, (S2)—50%) compared to sedimentary soils ((N)—11%, (S3)—78% and (S2)—11%). Based on the suitability classes of the different soils derived from dissimilar parent materials, appropriate site-specific soil management is needed to improve oil palm yields, especially with emphasis on K fertilization and improved soil water management. Plantation management in coastal plains of South West Cameroon therefore should factor in differences in soil parent material.

瓯江流域下游温州平原地下水化学演化特征、控制因素及对人体健康的影响

【研究目的】滨海地带地下水化学演化特征及其控制因素研究对沿海城市地下水资源可持续利用具有重要意义。【研究方法】在野外调查取样和历史资料综合分析的基础上,运用水化学图解、离子比例关系、多元统计分析及环境同位素方法,系统分析了温州平原地下水化学演化特征,探讨了影响地下水化学演化的主要控制因素。【研究结果】(1)温州平原潜水以淡水为主,HCO_(3)^(-)、Na^(+)、Ca^(2+)占主导地位,承压水以微咸水和咸水为主,Cl^(-)、Na^(+)占绝对优势;(2)从山前到海积平原,研究区潜水由低矿化度的HCO3型水向较高矿化度的Cl型水转变,主要受天然水化学作用控制,人类活动使局部地区地下水化学出现异常;(3)十年尺度上,潜水主要组分含量存在一定程度下降,水化学类型向Cl^(-)比重减少、HCO_(3)^(-)比重增加的方向演化;(4)水岩相互作用、海水作用、氧化还原环境等自然因素和工农业生产、生活排污等人为因素是温州平原地下水化学演化的主要控制因素。【结论】地下水健康风险评价结果显示,区内地下水存在一定的潜在非致癌风险,潜水的非致癌风险小于承压水,饮水途径摄入是危害人体的主要途径,相同环境下儿童的非致癌风险高于成人。因此,有必要对存在健康风险的地下水进行长期监测,加强这类地区的地下水资源管理和污染防治。

广东省沿海平原中小河流淹没图编制方法初探

广东省沿海平原中小河流具有比降缓、潮汐影响大、淹没范围广和堤围密集等特点,其淹没图编制至今无统一方法。该文通过Mike21和Arcgis软件,结合河流特性,参考《山丘区中小河流洪水淹没图编制技术指引》,以乌坎河为例探求出一种适用于广东省沿海平原中小河流的淹没图编制方法。该方法具有可操作性强、准确性较高和适用范围较广等特点,为后续广东省沿海平原中小河流淹没图制作提供参考。

典型滨海平原城市地下空间地质适宜性评价

地下空间地质适宜性评价是城市地下空间资源开发利用的重要前提。滨海平原城市因其特定的城市类型,需建立特定的地质适宜性评价体系来指导地下空间地质适宜性评价。本文以我国典型滨海平原城市日照市为研究区,深入分析了影响地下空间开发的地质环境因素,提出了基于基础性地质和约束性地质条件的滨海平原城市地质适宜性评价指标体系,进一步采用经验分值法、熵权法和综合评价模型厘定了研究区浅层(0~15m)和次浅层(15~30m)地下空间地质适宜性分区。结果显示,评价指标中水位埋深、断裂带、地面沉降和海水入侵等对地下空间地质适宜性的影响较大。研究区浅层和次浅层地下空间地质适宜性以适宜和较适宜为主,约占研究区面积的90%,不适宜区域约占研究区面积的10%。

沿海高铁滨海平原软土力学特性研究

根据沿海高铁汕头至汕尾段定测勘探成果,对上千组土工试验数据进行统计分析,研究不同沉积成因的软土工程地质特性,并结合实际工程分析软土对工程建设的影响。结果表明:滨海沉积相、泻湖相、三角洲冲积相软土含水量约40%~60%、孔隙比大于1.2、压缩系数大于0.5,结构松散软弱,属于高压缩性土;榕江三角洲冲积相软土分为两层,形成于两个海潮沉积旋回,其承载力特征值分别为60、80 kPa,两层淤泥质土需考虑软土震陷;三角洲沉积相粉细砂层多夹淤泥或淤泥质土,属层状构造土,力学性质具有横观各向同性,采用砂井或插塑板处理地基的效果较好。

Application of LiDAR Data for Hydrologic Assessments of Low-Gradient Coastal Watershed Drainage Characteristics

Documenting the recovery of hydrologic functions following perturbations of a landscape/watershed is important to address issues associated with land use change and ecosystem restoration. High resolution LiDAR data for the USDAForestServiceSanteeExperimentalForestin coastalSouth Carolina,USAwas used to delineate the remnant historical water management structures within the watersheds supporting bottomland hardwood forests that are typical of the re- gion. Hydrologic functions were altered during the early1700’s agricultural use period for rice cultivation, with changes to detention storage, impoundments, and runoff routing. Since late1800’s, the land was left to revert to forests, without direct intervention. The resultant bottomlands, while typical in terms of vegetative structure and composition, still have altered hydrologic pathways and functions due to the historical land use. Furthermore, an accurate estimate of the watershed drainage area (DA) contributing to stream flow is critical for reliable estimates of peak flow rate, runoff depth and coefficient, as well as water and chemical balance. Peak flow rate, a parameter widely used in design of channels and cross drainage structures, is calculated as a function of the DA and other parameters. However, in contrast with the upland watersheds, currently available topographic maps and digital elevation models (DEMs) used to estimate the DA are not adequate for flat, low-gradient Coastal Plain (LCP) landscape. In this paper we explore a case study of a 3rd order watershed (equivalent to 14-digit hydrologic unit code (HUC)) at headwaters of east branch of Cooper River draining to Charleston Harbor, SC to assess the drainage area and corresponding mean annual runoff coefficient based on various DEMs including LiDAR data. These analyses demonstrate a need for application of LiDAR-based DEMs together with field verification to improve the basis for assessments of hydrology, watershed drainage characteristics, and modeling in the LCP.

滨海平原区深层高氟地下水富集机理:以滦河三角洲为例

河北滨海平原区深层含水层存在高氟地下水,严重威胁居民用水安全。为查明其富集机理,本研究在现场采集69个深层地下水样品,对比分析低氟和高氟地下水的水化学和同位素特征。结果表明,高氟地下水主要存在于HCO_(3)-Na型地下水中,而低氟地下水化学类型以HCO_(3)-Ca·Na为主。PHREEQC饱和指数计算结果表明,地下水中萤石多为不饱和状态,方解石多为过饱和状态,这说明Ca^(2+)形成方解石沉淀有助于萤石的溶解,后者是地下水中F-的主要来源。线性回归结果表明,深层地下水Ca^(2+)和Na+之间发生阳离子交换作用,这一过程能够减少地下水中Ca^(2+)含量,进一步促进CaF2溶解。深层地下水中F-与pH和HCO_(3)-有较好的正相关性,表明微碱性环境和高含量HCO_(3)-有利于F-发生解吸附。此外,深层地下水中F-和Li含量呈显著的正相关,说明研究区地热水的混合作用可能直接影响深层地下水F-的富集。对比深层地下水与海水的水化学和同位素特征,发现研究区深层地下水氟富集不受海水入侵影响。

浙东沿海涂地土壤结构演变特征及机理研究

为了解涂地围垦利用过程中土壤结构的变化特征,探讨浙江沿海涂地土壤结构的演变及变化机理,以浙南—乐清湾和浙北—杭州湾为研究对象,采用田间采集不同围垦时间土壤的理化分析与室内加盐、施有机肥及干湿交替培养试验相结合的方法,分析了不同条件下土壤结构的变化。调查结果表明,从潮滩盐土经滨海盐土至潮土、水稻土,随着围垦利用时间的增加及土地利用方式的改变,土壤结构由松散状单粒为主转变为弱块状结构最后演变为稳定的块状结构,>0.25 mm水稳定性团聚体数量明显增加,同时水稳定性团聚体的粒径也逐渐增大。培养试验与土壤分析的结果表明:干湿交替和土壤脱盐是促使由潮滩盐土至滨海盐土水稳定性团聚体迅速增加的关键因素,而有机质的积累和耕作熟化是由滨海盐土至潮土、水稻土水稳定性团聚体逐渐增加的主要原因。

Spatiotemporal optical properties of dissolved organic matter in a sluice-controlled coastal plain river with both salinity and trophic gradients

Due to the combined effect of sluices and sea tide,the sluice-controlled coastal plain river would be characterized by both trophic state and salinity gradients,affecting the spatiotemporal optical properties of dissolved organicmatter(DOM).In this study,we investigated the spatiotemporal variation of water quality parameters and optical properties of DOM in the Haihe River,a representative sluice-controlled coastal plain river in Tianjin,China.A significant salinity gradient and four trophic states were observed in the water body of the Haihe River.Two humic-and one protein-like substances were identified from the DOM by the three-dimensional fluorescence spectra combined with the parallel factor(PARAFAC)analysis.Pearson’s correlation analysis and redundancy analysis(RDA)showed that the salinity significantly affected the abundance of chromophoric DOM(CDOM)but did not cause significant changes in the fluorescence optical characteristics.In addition,the effect of Trophic state index(TSI)on the CDOM abundance was greater than that on the fluorescence intensity of fluorescent dissolved organic matter(FDOM).In the water body with both salinity and trophic state gradients,TSI posed a greater influence than salinity on the CDOM abundance.Our results fill the research gap in spatiotemporal DOM characteristics and water quality variation in water bodies with both salinity and trophic state gradients.These results are beneficial for clarifying the joint influence of saline intrusion and sluices on the DOM characteristics and water quality in sluice-controlled coastal plain rivers.

基于分形理论的滨海城市与内陆平原城市空间形态特征对比研究

滨海城市作为海洋经济发展与内外联动交流的物质载体,城市拓展受到海岸线、腹地地貌等多重因素的影响,城市空间沿海岸线延伸,呈现带形、湾形等空间形态特征,与内陆城市存在显著差异。文章基于分形理论,对滨海城市与内陆平原城市的外部空间形态与内部主要功能用地布局进行横向对比,揭示内陆平原城市与滨海城市的空间形态和分形差异,并归纳解析其空间形态形成差异的影响因素,以期为滨海城市的城市形态优化和空间布局调整提供参考依据。

沿海平原地区桥址处风场特性实测研究

为研究沿海平原地区桥址处风场特性,采用VT-1相控阵多普勒雷达系统对横门水道附近某桥址处进行为期一年的风场实测。研究表明,该桥址处风速较好地服从Weibull分布;平原地区风场相较于河谷地区而言,主导风向随高度变化小;风速平均值与风向频度呈正相关,阵性与风向频度呈负相关;该桥址处平均风速剖面虽较好符合指数律,但是JTG/T 3360-01—2018《公路桥梁抗风设计规范》推荐的地表粗糙度系数α值并不适用;良态风风速剖面并不总是服从指数律,但是抗风设计所关注的高风速较好服从指数律。另外,提出了最大概率风速剖面的概念,相较于传统采用的平均风速剖面更具有合理性,采用该种风速剖面在桥梁抗风设计中进行风速推算时更为安全。