共查询到18条相似文献，搜索用时 102 毫秒
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本文采用生长波动率这个新的概念和指标，研究多金属结核生长过程中生长速率的变化规律，提取结核壳层中的古环境信息，重建结核生长历史。研究结果表明：多金属结核生长具有多阶段，多成因的特点，生长速率的波动是古环境变化的反映。 相似文献
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依据多金属结核ＣＣＣ１４剖面上Ｍｎ、Ｆｅ、Ｎｉ、Ｃｕ的含量和有关的公式，本文计算该结核生长过程中瞬时生长速率和Ｍｎ、Ｆｅ、Ｎｉ、Ｃｕ的瞬时通量，并在结核中建立时间标尺，划分和对比结核生长阶段，重建结核ＣＣＣ１４８．７９３Ｍａ，Ｂ．Ｐ．以来的生长历史。研究结果表明，采用由铁、锰含量计算结核生长速率的公式，可详细了解结核生长过程，并能识别与提取强核中古海洋信息记录。 相似文献
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本文阐述了中太平洋北部锰结核的成分及结构、构造的研究结果。结核可分为粗糙型和光滑型,内部呈现具有核心的同心层状构造,壳层可分为数个粗层。各粗层之间为不整合或假整合接触,粗层内微层呈韵律性排列。通过对粗层构造以及粗层内各韵律层的元素及矿物组分分布特点的研究,作者认为粗层的生长与当地沉积物的沉积间断或沉积速率减小有关,而微层的韵律性则是结核在滚动过程中生长造成的。文中并对结核的生长过程作了一般性讨论。 相似文献
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研究旨在提出深海多金属结核生长的数值模拟方法,以获取典型的结核宏观形貌,为后续结核输运过程的冲击碎裂仿真提供几何模型。根据已有的深海多金属结核采样研究结果,假定矿物沉积速率满足正态分布。将多阶段时变随机沉积模型嵌入ABAQUS UMESHMOTION子程序中,通过控制网格节点移动实现了结核多阶段随机生长模拟,给出了结核不同生长阶段的外形及截面特性模拟结果。分析了鱼骨、鲨鱼牙齿、板岩、鹅卵石等典型不同核心物质及矿物沉积速率变异性对结核生长过程的影响,确定了核心物质在海床淤泥中埋置深度对结核生长形态的影响。研究表明：基于网格节点移动的结核生长模拟技术可有效处理结核几何拓扑变化较小的生长过程,核心物质的初始形状及其在海床上的埋置深度是影响结核形貌的主要原因,而矿物沉积速率的变异性则主要影响结核表面的光滑度。 相似文献
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太平洋中部多金属结核生物地层学研究 总被引：1，自引：0，他引：1
本文利用钙质超微化生物地质学研究方法，分析鉴定了多金属结核中的钙质超微化石，建立了多金属结核生长层柱状剖面图，确定了多金属结核形成的三个生长阶段及其年代，为揭示多金属结核的成矿规律和分布规律提供了必要的地质资料。 相似文献
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多金属结核微层中元素的富集系数特征及其成因 总被引：4，自引：0，他引：4
作者定义元素富集系数（Ｋ）为结核样品中元素的含量与太平洋多金属结核的平均值的比值，并按Ｋ值大小将元素的富集程度分成六级。本文研究表明：多金属结核壳层中元素的富集系数是波动的；Ｋ＿（Ｍｎ）与Ｋ＿（Ｆｅ）呈负相关性，而与Ｋ＿（Ｎｉ）、Ｋ＿（ｃｕ）呈正相关性；按Ｍｎ／Ｆｅ和生长速率，多金属结核ＣＣＡ３３、ＣＣＢ２９、ＣＣＣ５０、ＣＣＣ１４的壳层，分别划分为８、７、１４、２４个微层；微层中元素富集程度与成因相关，结核生长间断面中，锰呈弱亏损至极亏损，铁弱亏损至较富集，铜弱亏损至较亏损，镍较亏损至极亏损，而由强缺氧性成岩作用为主所形成的微层中，锰、镍呈较富集至极富集，铜极富集，而铁极亏损。 相似文献
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海湾扇贝是雌雄同体的贝类 ,其壳色有橙、棕、黄、紫、白等色彩。利用壳色可遗传的特性 ,采用自体受精的交配策略 ,于 2 0 0 2年成功地建立了 4个橙色、3个紫色、4个白色等 3类共 1 1个海湾扇贝自交系 ,并对不同家系的受精卵大小、胚胎孵化率及幼虫、稚贝和养成阶段的生长速率与存活率等生物学参数进行了比较。结果表明 ,在幼虫和稚贝等早期发育阶段 ,3类壳色的不同家系在生长速率和存活率等方面没有表现出差异 ,但是在养成阶段 ,在高温的7、8月 ,白壳色家系的生长速率和存活率均明显高于其它 2种壳色的家系。 相似文献
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麦哲伦海山区MD、ME、MF海山富钴结壳特征 总被引：10，自引：0，他引：10
麦哲化海山区MD、ME、MF海山具有三层构造的结壳特征，研究表明，结壳可分为上部较致密层、中部疏松层、下部致密层。致密层构造单一，含很少脉石矿物；疏松层构造杂乱，含有大量脉石矿物；较致密层介于两者之间，壳层矿物有锰相矿物（主要为水羟锰矿）、铁相矿物和次要矿物（粘土矿物、钙十字沸石、石英、方解石、磷灰石等）。不同壳层地球化学特征具有明显差异性，Ce异常表明在结壳从下层到上层的生长过程中，环境的氧化性逐渐减弱，结壳^10Be测年结果表明，疏松层的生长速率最大，其次为致密层，较致密层的生长速率最小。推测区的最老的结壳的生长年代为中新世晚期，在4Ma以前，区内水动力条件很弱，氧化性较强；4－3．1MaBP水动力条件较强，氧化性较弱；2．6MaBP以来，水动力条件为强－弱波动期，氧化性较弱。 相似文献
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中培期和养成期墨西哥湾扇贝(Argopecten irradians concentricus)新品系养殖密度的研究 总被引：2，自引：0，他引：2
于2011年10至2012年4月选择同一批次的墨西哥湾扇贝贝苗,采用大板笼和小板笼对该贝类进行中间培育和养成实验,研究了中培期和养成期不同养殖密度对该贝类生长和存活的影响,分析了养成期养殖密度与经济效益的关系。结果表明,在中培阶段,随着养殖密度的增加,壳高、体质量、壳高相对生长率、体质量相对生长率、日增壳高、日增体质量和存活率呈下降趋势,方差分析表明,养殖密度对墨西哥湾扇贝存活率、壳高、体质量及相关生长速度参数产生显著影响（P﹤0.05）。大板笼养殖密度180个/层时,壳高为30.93mm、存活率为91.00%,小板笼养殖密度120个/层时,壳高30.84mm、存活率91.40%,Duncan法多重比较分析显示,中培阶段大板笼适宜的养殖密度为180个/层,小板笼适宜的养殖密度为120个/层。在养成阶段,随着养殖密度的升高,存活率、出肉率、壳高、体质量及相关生长速度参数呈下降趋势,方差分析表明,养殖密度对墨西哥湾扇贝存活率、出肉率、壳高、体质量及相关生长速度参数产生显著影响（P﹤0.05）。大板笼养殖密度60个/层时,壳高42.81mm、存活率86.33%、出肉率16.75%,小板笼养殖密度50个/层时,壳高42.35mm、存活率84.21%、出肉率16.91%。养成期经济效益分析表明,随着扇贝养殖密度的升高,每500g肉柱的粒数呈逐渐递增趋势,而每粒肉柱的重量和肉柱的价格呈逐渐递减趋势,养殖笼单层产量、产值和收益均呈现峰值变化规律。大板笼养殖密度为60个/层时,产量、产值和收益均达最大值,分别为177.17g/层、5.03元/层和2.33元/层,小板笼养殖密度为50个/层时,产量、产值和收益均取得最大值,分别为153.15g/层、4.48元/层和2.27元/层。经多重比较不同养殖密度下扇贝生长、存活和生长速度的差异,以及综合分析养殖密度与经济效益的关系,提出养成期大板笼适宜的养殖密度为60个/层,小板笼适宜的养殖密度为50个/层。 相似文献
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Philomène A. Verlaan Author Vitae David S. Cronan Author Vitae Charles L. Morgan Author Vitae 《Progress in Oceanography》2004,63(3):125-158
Regional variation of Mn, Fe, Co, Ni and Cu in ferromanganese oxides (nodules and crusts) in the central south Pacific is related to primary productivity, oxygen minimum layer, and calcium carbonate compensation depth. The largely latitudinal influence of these environmental parameters on nodule and crust composition reflects their predominantly latitudinal variation. Primary productivity is the principal regional environmental control, influencing diagenetic enrichment of these elements in nodules through its effect, mediated by the CCD, on supply and concentration of labile organic matter vs. carbonate remains to the sediments. It influences hydrogenetic enrichment of these elements in nodules and crusts through its effect, mediated by the oxygen minimum layer (mainly in the case of crusts), on their export from surface waters.The elements’ varying susceptibility to being scavenged or organically bound influences the contrasting composition of diagenetic vs. hydrogenetic ferromanganese oxides, which is further influenced by depth. Hydrogenesis is the fundamental process governing nodule and crust formation, superimposed on which is diagenesis under specific circumstances; both are subject to intermittent interruption, diminution and augmentation by changes in environmental parameters. Application of regionally operative environmental controls locally explains local compositional variations and helps refine exploration criteria for economically viable nodules and crusts. 相似文献
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Manganese nodules of the Clarion–Clipperton Fracture Zone (CCFZ) in the NE Pacific Ocean are highly enriched in Ni, Cu, Co, Mo and rare-earth elements, and thus may be the subject of future mining operations. Elucidating the depositional and biogeochemical processes that contribute to nodule formation, as well as the respective redox environment, in both water column and sediment, supports our ability to locate future nodule deposits and to evaluate the potential ecological and environmental effects of future deep-sea mining. For these purposes we studied the local hydrodynamics and pore-water geochemistry with respect to the nodule coverage at four sites in the eastern CCFZ. Furthermore, we carried out selective leaching experiments at these sites in order to assess the potential mobility of Mn in the solid phase, and compared them with the spatial variations in sedimentation rates. We found that the oxygen penetration depth is 180–300 cm at all four sites, while reduction of Mn and NO3− is only significant below the oxygen penetration depth at sites with small or no nodules on the sediment surface. At the site without nodules, potential microbial respiration rates, determined by incubation experiments using 14C-labeled acetate, are slightly higher than at sites with nodules. Leaching experiments showed that surface sediments covered with big or medium-sized nodules are enriched in mobilizable Mn. Our deep oxygen measurements and pore-water data suggest that hydrogenetic and oxic-diagenetic processes control the present-day nodule growth at these sites, since free manganese from deeper sediments is unable to reach the sediment surface. We propose that the observed strong lateral contrasts in nodule size and abundance are sensitive to sedimentation rates, which in turn, are controlled by small-scale variations in seafloor topography and bottom-water current intensity. 相似文献
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南海铁锰结核(壳)的地球化学特征 总被引：1，自引：0，他引：1
本文研究了南海中部铁锰结核(壳)的地球化学特征。南海铁锰结核(壳)以高Mn富Ni为特征。但不同沉积部位的铁锰结核(壳),化学成分也有一定的差异,这是受不同沉积区的物源特性,地化环境差异和沉积成矿过程中环境的变化所影响的结果。 相似文献
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Dietrich Heye 《Progress in Oceanography》1978,7(5-6)
Twenty-four manganese nodules from the surface of the sea floor and fifteen buried nodules were studied. With three exceptions, the nodules were collected from the area covered by Valdivia Cruise VA 04 some 1200 nautical miles southeast of Hawaii.Age determinations were made using the ionium method. In order to get a true reproduction of the activity distribution in the nodules, they were cut in half and placed for one month on nuclear emulsion plates to determine the α-activity of the ionium and its daughter products. Special methods of counting the α-tracks resolution to depth intervals of 0.125 mm. For the first time it was possible to resolve zones of rapid growth (impulse growth) with growth rates, s > 50 mm/106 yr and interruptions in growth. With few exceptions the average rate of growth of all nodules was surprisingly uniform at 4–9 mm/10 yr. No growth could be recognized radioactively in the buried nodules. One exceptional nodule has had recent impulse growth and, in the material formed, the ionium is not yet in equilibrium with its daughter products. Individual layers in one nodule from the Indian Ocean could be dated and an average time interval of t = 2600±400 yr was necessary to form one layer. The alternation between iron and manganese-rich parts of the nodules was made visible by colour differences resulting from special treatment of cut surfaces with HCl vapour. The zones of slow growth of one nodule are relatively enriched in iron.Earlier attempts to find paleomagnetic reversals in manganese nodules have been continued. Despite considerable improvement in areal resolution, reversals were not detected in the nodules studied. Comparisons of the surface structure, microstructure in section and the radiometric dating show that there are erosion surfaces and growth surfaces on the outer surfaces of the manganese nodules. The formation of cracks in the nodules was studied in particular. The model of age-dependent nodule shrinkage and cracking surprisingly indicates that the nodules break after exceeding a certain age and/or size. Consequently, the breaking apart of manganese nodules is a continuous process not of catastrophic or discontinuous origin. The microstructure of the nodules exhibits differences in the mechanism of accretion and accretion rate of material, shortly referred to as accretion form. Thus non-directional growth inside the nodules as well as a directional growth may be observed. Those nodules with large accretion forms have grown faster than smaller ones. Consequently, parallel layers indicate slow growth. The upper surfaces of the nodules, protruding into the bottom water appear to be more prone to growth disturbances than the lower surfaces, immersed in the sediment. Features of some nodules show, that as they develop, they neither turned nor rolled. Yet unknown is the mechanism that keeps the nodules at the surface during continuous sedimentation. All in all, the nodules remain the objects of their own distinctive problems. The hope of using them as a kind of history book still seems to be very remote. 相似文献
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Distribution characteristics of cobalt‐rich manganese deposits were evaluated from stereo photographs and video data on a seamount in the central Pacific Ocean by image analysis, photogrammetric technique, and visual observations. The results show that many locations have high crust coverages with highly undulating micro‐topography. High nodule coverages occur on relatively flat seafloor, and the nodule size distribution varies from uniform to inhomogeneous among different locations. Distribution of these deposits along detailed topographic sections show that the seafloor can be divided into nodule dominant zones between 0° and 3° slopes, with sediment patches up to 4° slopes; and crust dominant zones, which occur on slopes higher than 15°. The transition zone, between 4° and 15° slopes, has many locations, where nodules and crusts co‐occur in varying percentages. The observation of crust outcrops among sediments and nodules, as well as in the gravity core samples, indicates the presence of shallow buried crusts as well, which can substantially enhance resource evaluation of the deposits. 相似文献
17.
Deep Seabed Mining: Past Failures and Future Prospects 总被引：8，自引：0，他引：8
G. P. Glasby 《Marine Georesources & Geotechnology》2002,20(2):161-176
The first attempt to exploit deep-sea manganese nodules ended in failure as a result of the collapse of world metal prices, the onerous provisions imposed by the U.N. Convention on the Law of the Sea (UNCLOS), and the overoptimistic assumptions about the viability of nodule mining. Attention then focused on Co-rich manganese crusts from seamounts. Since the mid-1980s, a number of new players have committed themselves to long-term programs to establish the viability of mining deep-sea manganese nodules. These programs require heavy subsidy by the host governments. Au-rich submarine hydrothermal deposits located at convergent plate margins are now emerging as a more promising prospect for mining than deep-sea manganese deposits. 相似文献
18.
G. P. Glasby 《Marine Georesources & Geotechnology》2013,31(2):161-176
The first attempt to exploit deep-sea manganese nodules ended in failure as a result of the collapse of world metal prices, the onerous provisions imposed by the U.N. Convention on the Law of the Sea (UNCLOS), and the overoptimistic assumptions about the viability of nodule mining. Attention then focused on Co-rich manganese crusts from seamounts. Since the mid-1980s, a number of new players have committed themselves to long-term programs to establish the viability of mining deep-sea manganese nodules. These programs require heavy subsidy by the host governments. Au-rich submarine hydrothermal deposits located at convergent plate margins are now emerging as a more promising prospect for mining than deep-sea manganese deposits. 相似文献