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1.
张文开 《台湾海峡》1997,16(1):100-105
长乐东部和海坛是福建省的主要风沙分布区,风成沙是重要的自然资源。本文分析了风沙地貌类型及其分布特征、风成沙成分等,探讨了风沙资源的开发利用和保护等问题。  相似文献   

2.
厦门岛东北岸海岸风沙运动观测研究   总被引:2,自引:0,他引:2  
厦门岛东北海岸是台湾海峡西岸风沙最活跃的岸段之一,其中香山-五通岸段由于新建设了宽阔的人造海滩,风沙更加肆虐.为了解该岸段海岸风沙的运动特征和影响程度,分别于2007年11月22日、12月31日和2008年1月13日使用捕沙器定时取样和同步风速观测的方法进行风沙观测.结果如下:(1)人造海滩的风沙起沙风速约为6.9m/s,该风速以上,风沙随风速的增加而增加;(2)海岸风沙在离地面1m高度内运动,其中的94.8%在0.25m高度下运行;(3)人造海滩的风沙粗于自然海滩的风沙,随风沙运动高度从低到高,平均粒径由细到粗,分选性变好;(4)本岸段>6.9m/sNE风时平均输沙率约为2.776kg/m2h,单宽输沙量约为374.84kg/h,即8.995t/d.  相似文献   

3.
中国海岸风成沙ESR测年的研究   总被引:9,自引:0,他引:9  
介绍ESR测年的基本原理,并讨论风成沙Ge心测年的可行性、风成沙E'心的特征、测年误差及可靠性等问题。1992-1993年在渤、黄、东、南海沿岸采集的100余个风成沙样品ESR测年实验表明,绝大部分海岸风成沙的年龄为1-7万年。  相似文献   

4.
为搞清楚黄河三角洲的发育以及黄河三角洲进积和贝壳堤形成的关系 , 在黄河三角洲两个站位上打了钻 . 因为岩心采取率的原因 , H9601站位打了两个紧相邻的钻孔 (Ⅰ , Ⅲ ), 该站位位于 37° 40.5′ N、 118° 28.7′ E, 山东省境内现代黄河三角洲之上 , 1855年海岸线和第二道贝壳堤 (原文中称作贝壳堤 H2)东北 , 孔口高程 + 5.5 m. H9602站位只有一个钻孔Ⅱ , 位于山东省境内 37° 4.8′ N、 118° 54.3′ E,1855年海岸线和第二道贝壳堤之西南 , 第三道贝壳堤 (原文中称作贝壳堤 H1)之东北 , H9601站位之西偏南 , 孔口高程 + 4.8 m. 两个站位共测得 30个 14C年龄数据 .  相似文献   

5.
蔡爱智  龚金美 《台湾海峡》1992,11(2):112-117
本文研究了福建海坛岛芦洋浦平原的海进沙与风沙层序。结果表明,芦洋浦平原原是一个水深20~30m、走向NNE的海湾,全新世初期的海进沙层厚2~5m覆盖在陆相冲积和风化层上。后来,海平面波动,从台湾海峡推来残留沙超覆其上。经一段时间的正常环境后,距今约2400~2000a,由于地球气候的变化,风沙逐渐发育,厚5~10m的风沙层埋盖了海湾沉积,建造了面积68km~2的大沙坪和半封闭的泻湖。  相似文献   

6.
我国主要育珠贝(蚌)贝壳珍珠层的扫描电子显微镜研究   总被引:8,自引:0,他引:8  
采用扫描电子显微镜(SEM)对我国海水马氏珍珠贝Pinctada martensi(Dunker),大珠母贝Pinctada maxima(Jameson)、企鹅珍珠贝Pteria penguin(Roeding)和淡水三角帆蚌Hy-riopsis cumingii(Lea)贝壳珍珠层内层面的形貌特征进行了研究,结果表明,4种贝壳珍珠层均呈砖墙式结构,珍珠层中文五笔型小板片呈不规则多边形至六边形,直径为1.3-4.5μm,厚度0.35-0.85μm,同一种类贝壳中文石小板片的形状及粒径均匀一致,反映了生物矿物化的特殊性。珍珠层沿壳内层面与棱柱层过滤带中均存在初始生长的文石小晶体结构排列较混乱的现象,与成熟珍珠层中文石小板片的定向排列结构明显不同。  相似文献   

7.
地质矿产部海洋地质研究所最近在黄河口地区的海岸带调查中发现数条古贝壳堤.长数十公里,宽数百米,厚度较大,十分稳定,埋藏较浅.这些古贝壳堤沿西北走向进入河北省境内,并可能与歧口贝壳堤、巨葛庄贝壳堤、天津育婴堂贝壳堤相连.贝壳堤具向上变细的层序,发育冲洗交错层理和风暴层理.向海一侧陡,向陆一侧缓.其展布方向明显地受风浪和潮流控制.在贝壳堤的向陆一方往往伴随有发育较差的泻湖和滨后沼泽.组成贝壳堤的贝类主要有石蛤、金蛤、文蛤、日本镜蛤、米蛤、锥螺、蛏、牡蛎等.以贝壳碎屑为主.贝壳堤中含少量砂,以石英为主,分选好,磨圆程度甚高,在石英砂中磁铁矿含量较高,显然古贝壳堤是高能环境的产物.从地层层序上看,古贝壳堤以及现在沿低潮线正在发育的贝壳堤,均盖在三角洲河流沉积之上,所以从广意上说,它是海进过程的产物,是相对稳定一轻微蚀退海岸的低潮线的标志.古贝壳堤又往往为沼泽和泻湖相沉积所覆盖.其上为三角洲平原相的河流和分流问沉积.表现了一个完整的海退层序.  相似文献   

8.
滨海城市海岸线的空间特征演变规律及其影响因素对于陆海统筹的空间规划具有重要的研究意义。将改进的归一化水体指数(Modified Normalized Difference Water Index, MNDWI)和Canny边缘检测法相结合,从Landsat遥感影像中提取了厦门岛1976-2018年共九景海岸线,并对其进行分形分析。采用自主编写的图像分形维数计算程序计算了研究期间厦门岛海岸线的盒维数,总结分析了其变化趋势以及变化原因。结果表明:厦门岛的海岸线具有分形特性,其盒维数的变化范围为1.098 9~1.118 1,先后经历降低、增加、再降低和最后缓变四个阶段,总体呈现下降的趋势;进一步分析,发现厦门岛在快速发展进程中,海洋工程对海岸线空间形态复杂性有显著的影响,其中,填海造陆工程的实施导致海岸线盒维数降低,而港口、码头建设却导致盒维数增加。盒维数的变化程度间接反映了海洋工程对海岸带的改造程度。本研究对厦门海岸线分形特征的分析,可为该区域资源开发、生态保护和城市规划提供有价值的参考依据。  相似文献   

9.
海坛岛风沙表层沉积物的粒度分布特征   总被引:5,自引:0,他引:5  
陈方  李祖光 《台湾海峡》1993,12(4):385-392
本文对海坛岛风沙表层沉积物的粒度分布特征进行研究。结果表明:海坛岛风沙沉积物主要是由海岸带基岩和第四纪松散堆积物及闽江南下沿岸流所携带的泥沙,在海洋动力作用下堆积于海滩上,而后在强劲的NNE向向岸盛行风作用下,海滩沙向陆搬运堆积而成的。风成沙的主要粒级为中沙,平均粒径为1.73Ф;分选较好,标准差的平均值为0.68,偏差多近于对称,偏态平均值为-0.02;峰态窄,峰态平均值为1.21。其搬运方式单  相似文献   

10.
第 1期冲绳海槽表层沉积硅藻对黑潮流的响应蓝东兆 ,方 琦 ,廖连招 (1)…………………………………………………………福建深沪湾潮间带全新世有孔虫及其环境意义王绍鸿 ,俞鸣同 ,唐丽玉 ,赵希涛 ,王雪梅 ,黄向华 (6 )………………………厦门岛东南海岸贝壳层与风沙的研究杨顺良 ,郑承忠 ,翁宇斌 ,郭允谋 (12 )……………………………………………………具抗肿瘤活性的海洋微生物菌株的初步筛选李 根 ,陈瑞川 ,林 昱 (18)……………………………………………………台湾海峡浮游植物生物量和初级生产力的粒级结构及碳流途径黄邦钦 ,洪华生…  相似文献   

11.
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.  相似文献   

12.
海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明:土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。  相似文献   

13.
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.  相似文献   

14.
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.  相似文献   

15.
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.  相似文献   

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18.
The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.  相似文献   

19.
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria ( 〉 99% ), but also between polar marine bacteria and bacteria from other aquatic environments ( ≥ 98.8% ), including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.  相似文献   

20.
Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.  相似文献   

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