共查询到20条相似文献，搜索用时 31 毫秒
1.
大洋富钴结壳成因机制的探讨——水成因证据 总被引：3，自引：0，他引：3
根据对大洋富钴结壳的分层与年龄、分层与生长速率、生长间断等观测事实,以及大洋富钴结壳主量元素锰、铁元素及钴元素、铂元素、稀土元素、氦同位素、锇同位素等的水成富集,指出大洋富钴结壳是水成因的,进而指出富钴结壳的形成与基岩无关,水动力条件、最低含氧带、生物作用等可能对富钴结壳的形成有控制作用。同时,富钴结壳不一定只生长在岩石裸露的海山上,在沉积物覆盖的海山区也有可能找到富钴结壳。 相似文献
2.
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
3.
Andrea Koschinsky Marc Van Gerven Peter Halbach 《Marine Georesources & Geotechnology》2013,31(4):375-391
Ferromanganese crusts comparable with central Pacific occurrences with respect to thickness and extension have been discovered at the Tropic Seamount in the subtropical NE Atlantic. A comparison with typical hydrogenetic crusts from a central Pacific seamount revealed lower concentration of the Mn phase with Mn, Co, Ni, Zn, and Cu but a strongly increased terrigenous input of Fe, Pb, Al, and Si in the Atlantic crusts. Growth rates are increased compared with the Pacific crusts, and crust ages average at 10 My. The old phosphatized crust generation that started to grow about 20 My ago on the Pacific seamounts is not pronounced at the Tropic Seamount. The typical hydrographic and morphological parameters for hyrogenetic crust growth have also been found at the Tropic Seamount, which implies that the Tropic Seamount crusts have developed according to the hydrogenetic growth model. There are no indications of hydrothermal influence. 相似文献
4.
南海铁锰结核(壳)的元素地球化学研究 总被引：1，自引：0，他引：1
本文利用南海11个铁锰结核(壳)样品的化学分析资料,研究了铁锰结核(壳)中Fe,Mn,Cu,Co,Ni,Pb,Zn,Cr,K,Na,Ca,Mg,Si,P,Al,Ti,Sr,Ba及∑REE的元素地球化学特征。结果表明:(1)铁锰结核(壳)以高Fe,∑REE,低Mn,Cu,Co,Ni等元素为主要特征;(2)铁锰结核(壳)中Fe,Mn间无明显相关,而Fe与∑REE,∑Ce,∑Y呈弱的正相关,Mn与∑REE,∑Ce,∑Y呈明显的正相关,结壳中Fe,Mn与Si,Al,Cu Co Ni呈负相关;(3)结核(壳)中Mn/Fe与Cu/Ni,Ce/La呈负相关,Mn/Fe主要受Mn控制;(4)结核(壳)中Fe,∑REE等元素主要来自南海陆源中酸性岩类的风化、淋滤和沉积。 相似文献
5.
A sampling expedition has shown that largely hydrogenetic marine ferromanganese deposits occur in the Christmas Island region south of Java (~10°S), as small nodules on seamount slopes and abyssal plains (red clay), and as thick crusts on volcanic ridges and seamounts. Vernadite is dominant, with birnessite, jacobsite and todorokite common. Nodules were recovered in 25% of free-fall grab stations in water 4600-5900 m deep, and are not abundant where present. The nodules average 9.6% Fe, 19.7% Mn, 0.51% Ni, 0.49% Cu, and 0.12% Co. Crusts are common in water 1450-3700 m deep, with average deposition rates of 1-1.5 mm / m.y. The crusts average 13.9% Fe, 16.2% Mn, 0.35% Ni, 0.11% Cu, and 0.44% Co. Cobalt grades are higher (~0.8%) in shallower water ( < 2500 m), so future exploration should concentrate on depths of 500-1500 m near the oxygen minimum zone. 相似文献
6.
2017年8月中国科学院海洋研究所在西太平洋低纬度海区的卡罗琳洋脊CM4海山开展了多学科综合调查,发现该海山山体表面分布着大量的铁锰结壳。本文对该海山的5个铁锰结壳样品进行了矿物学和地球化学研究,利用X射线衍射(XRD)、电感耦合等离子光谱及质谱(ICP-OES、ICP-MS)等测试技术分析了铁锰结壳的矿物组成、主微量元素和稀土元素含量,并进一步探讨了铁锰结壳的成因类型。结果表明,该海山铁锰结壳的矿物组成以水羟锰矿为主,含有少量钡镁锰矿、水钠锰矿、针铁矿、纤铁矿、石英和方解石。该海山铁锰结壳的Mn、Fe、Co、Ni、Cu元素平均含量分别为24.24%、15.14%、0.16%、0.34%、0.01%。与全球各大洋海山区铁锰结壳相比,该海山样品的Cu含量很低。该海山铁锰结壳的稀土元素(REY)含量相对偏低,总体为轻稀土(LREE)富集;稀土(REY)配分模式显示相对平坦的特征,呈明显的Ce正异常,轻微的Y负异常和Ho正异常。样品的矿物组成、元素比值、元素组合等都表明该海山铁锰结壳属于水成成因,未受明显的成岩作用影响。 相似文献
7.
J. N. Pattan G. Parthiban Ankeeta Amonkar Sufiyan A. Shaikh S. Jai Sankar 《Marine Georesources & Geotechnology》2017,35(8):1147-1157
Thirty-three bulk ferromanganese nodules from the sediment–water interface of siliceous sediment domain from the Central Indian Ocean Basin were analyzed for 50 elements including 6 new (Be, As, Se, Sn, Sb, and Bi) using inductively coupled plasma–mass spectrometer. The Mn/Fe ratio and triangular plot (Fe-Mn-{Cu+Ni+Co?×?10}) suggest that ferromanganese nodules are of hydrogenetic, early diagenetic, and diagenetic origin. In the ferromanganese nodules, Mo, Sb, Bi, and As are highly enriched ～320, 160, 90, and 50 times compared with upper continental crust, respectively. A majority of the elements such as Be, Sc, Ti, V, Co, As, Se, Sr, Y, Zr, Nb, Sn, rare earth elements (REEs), Pb, Bi, P, Th, U, Hf, and Ta are associated with Fe, whereas, Cu, Ni, Zn, Mo, Li, Ga, Sb, Mg, and Cs are associated with Mn in the ferromanganese nodules. Redox proxies such as U/Th (0.14) and Mo/Mn (0.0019) ratio in the ferromanganese nodules suggest their formation under oxic conditions. 相似文献
8.
S. D. Iyer 《Geo-Marine Letters》1991,11(1):44-50
SEM/probe analyses of two ferromanganese crusts from the Central Indian Basin, formed on basalt substrate, reveal botryoids
and cusps. The botryoids composed of δ-MnO2, are enriched in Co, and the cusps and laminations with todorokite are enriched in Ni and Cu. Microstructural and elemental
variations, from the ferromanganese crust outer surface to the basalt substrate, probably reflect changes in the accretion
or in the source of metals. The major source of the crust metals is the seawater, as indicated by the Mn/Fe ratio of unity
and by the microstructures. 相似文献
9.
Hisaaki Sato 《Marine Georesources & Geotechnology》2018,36(7):768-780
We propose a geochemical parameter, “metal flux” in evaluating hydrogenetic Co-rich ferromanganese crust deposits in the Pacific seamount area, that is based on physical, chemical, and geological characterization of the integrated growth piles of crusts. We calculated the metal flux for fifteen sites from different depths ranging between 900-6000m from different seamounts. The secular and areal variations of metal flux indicate a strong geological controls, and also can be a reliable tool for estimating an economic potential of the crusts. The Co flux decreases with increasing water depth, followed by almost constant flux of Ni and Mn. The Al and Fe fluxes vary with regions, indicating higher values in the western regions near the island arc probably related to a supply from the Asian continents. The results imply that Co, a redox sensitive metal element, is controlled by redox conditions of seawater, while Fe and Al are by terrigenous input. The metal flux reflects global and regional conditions and controls the compositional diversity of metals, thus consequently, the parameter can be a reliable powerful tool to estimate or single out more potential areas. 相似文献
10.
《Marine Geology》2006,225(1-4):145-156
Manganese oxide crusts were recovered from Baby Bare seamount in order to investigate the history of off-axis hydrothermal venting. Baby Bare is a small basement high protruding from a regional sediment cover on the eastern flank of the Juan de Fuca Ridge that acts as a focus for discharging crustal fluids. Stratabound Mn-oxide crusts were collected where warm venting has been observed near the seamount summit. Mn-oxide crusts are composed primarily of 10 Å manganate ± pyrolusite, with minor nontronite, saponite, and/or barite. These assemblage and chemical characteristics such as high Mn/Fe ratios and low trace metal and REE concentrations are indicative of a hydrothermal origin. Minimum ages for these deposits, calculated using growth rates (324 to ∼ 1800 mm/Ma) and estimated thicknesses of manganese outcrops, show that Baby Bare has been hydrothermally active for at least 0.5 Myr, and possibly since its formation (1.7–2.7 Ma). Hydrothermal manganese oxide crusts such as these from Baby Bare record interactions between the hydrothermal fluids and seawater and are important tools for estimating the longevity of off-axis hydrothermal activity. 相似文献
11.
西太平洋麦哲伦海山区是全球重要的铁锰结壳资源分布区,具有丰富的稀土元素资源潜力。本文对采自麦哲伦海山区Kocebu海山的11个铁锰结壳表层样(<1 mm)进行稀土元素地球化学研究,探讨其含量特征、成因和影响稀土元素富集的环境因素。结果表明:Kocebu海山铁锰结壳表层样品ΣREY(Rare earth elements and yttrium)平均含量为1366 mg/kg,低于前人在麦哲伦海山区其他海山以及邻近的马尔库斯–威克海山区的分析结果;样品轻稀土富集和Ce正异常(平均值为1.45)特征以及稀土元素成因图解、配分曲线和分配系数曲线等均表明该海山结壳属于水成成因;海水中稀土元素含量和溶解氧含量是控制结壳生长的关键环境参数,二者在Kocebu海山所在海区的浅水环境中含量较低;结壳ΣREY含量偏低与采样点水深较浅导致的海水稀土元素含量和溶解氧含量较低密切相关,受碎屑矿物的稀释作用影响较小。在开展铁锰结壳地球化学特征研究和资源勘探评价时应充分考虑采样水深的分布范围,局部水深样品的分析结果可能导致研究结果出现较大偏差。 相似文献
12.
《Deep Sea Research Part I: Oceanographic Research Papers》1999,46(5):855-875
Principal Component and other statistical analyses of chemical and mineralogical data of Fe–Mn oxyhydroxide crusts and their underlying rock substrates in the central Pacific indicate that substrate rocks do not influence crust composition. Two ridges near Johnston Atoll were dredged repetitively and up to seven substrate rock types were recovered from small areas of similar water depths. Crusts were analyzed mineralogically and chemically for 24 elements, and substrates were analyzed mineralogically and chemically for the 10 major oxides. Compositions of crusts on phosphatized substrates are distinctly different from crusts on substrates containing no phosphorite. However, that relationship only indicates that the episodes of phosphatization that mineralized the substrate rocks also mineralized the crusts that grew on them. A two-fold increase in copper contents in crusts that grew on phosphatized clastic substrate rocks, relative to crusts on other substrate rock types, is also associated with phosphatization and must have resulted from chemical reorganization during diagenesis. Phosphatized crusts show increases in Sr, Zn, Ca, Ba, Cu, Ce, V, and Mo contents and decreases in Fe, Si, and As contents relative to non-phosphatized crusts. Our statistical results support previous studies which show that crust compositions reflect predominantly direct precipitation from seawater (hydrogenetic), and to lesser extents reflect detrital input and diagenetic replacement of parts of the older crust generation by carbonate fluorapatite. 相似文献
13.
富Co铁锰结壳铂族元素与铼-锇同位素组成及其意义 总被引：13，自引：0，他引：13
用ICP－MS测定了太平洋富Co铁锰结壳铂族元素和铼－锇同位素组成。富Co铁锰结壳不仅异常富集铂族元素，而且铂族元素及其它亲铁元素的配发与陨石特征非常相似。铁锰结壳的铼－锇同位素组成明显有别于大陆地壳岩石，和K－T界线沉积物相似，接近陨石值。世界大洋范围内的富Co铁锰结壳均产于远离海底构造热液活动区，几乎不可能受到地幔源热液作用的直接影响。因此，富Co铁锰结壳中的铂族元素可能部分来源于地外物质。 相似文献
14.
A widespread distribution of hydrothermal and hydrogenetic manganese deposits is described in the results of the Hakurei‐Maru cruises conducted in the Bonin Arc areas of the West Pacific from 1984 to 1989. Manganese deposits occur in the active volcano chains, back‐arc basins, remnant back‐arc ridges, and oceanic seamounts. The hydrogenetic iron‐manganese deposits commonly form earthly black crusts and nodules on the topographic highs of inactive ridges and old seamounts, sometimes as thick as 10 cm. They are always composed of the iron‐manganese mineral vernadite. Co and Ni contents are relatively high in the crusts from the seamounts in the open Pacific Ocean (up to 1.1% Co and 1.0% Ni). Two generations of distinct chemistry and texture are typical of these crusts, which can be compared to reported thick crusts from the Central Pacific seamounts. The hydrothermal deposits, characterized by dense, submetallic, and gray appearance, are dominant in the recent and also in past submarine volcanoes of the island‐arc systems. Evidence of past hydrothermal activity was ascertained as fossil hydrothermal manganese deposits inside the hydrogenetic nodules or beneath the hydrogenetic crusts over the Tertiary island arc. Their component minerals are considered to be todorokite and bimessite (stable and contractible upon dehydration), having almost negligible amounts of Fe, Si, Al, Ni, Co, Zn, Pb, Cu, etc. In the small model site, the Kaikata Seamount hydrothermal area, the presumably recent hydrothermal activity has yielded thin slabs of pure manganate deposits growing downward within volcanic and sand layers. Early diagenetic influence is negligible on nodules of this area. 相似文献
15.
全球三大洋海山钴结壳资源量估算 总被引：8，自引：0，他引：8
钴结壳具有Co、Ni、Cu和Mn及其他金属的潜在矿产资源和储存在结壳层中古环境信息的双重意义。与深海多金属结核和热液硫化物矿床相比,具有较高Co、Ni和Pt含量的海山钴结壳有可能成为商业勘探的潜在目标。为合理地估算出全球三大洋海山钴结壳资源量,基于我国西太平洋海山钴结壳拖网采样调查资料和对太平洋海山钴结壳资源分布规律和钴结壳矿区圈定参数指标的深入研究,按海山不同高度、不同洋壳年龄赋予不同结壳厚度,进而计算出全球三大洋海山钴结壳分布面积为3 039 452.14km2和干结壳资源量为(1 081.166 1~2 162.332 2)×108 t。太平洋海山钴结壳分布面积为2 123 087.12km2和干结壳资源量为(513.244~1 026.488)×108 t,大西洋海山钴结壳分布面积为512 509.74km2和干结壳资源量为(116.503 2~233.006 4)×108 t,印度洋海山钴结壳分布面积为403 855.28km2和干结壳资源量为(81.484 9~162.969 8)×108 t。三大洋海山钴结壳的Mn、Co、Ni和Cu金属量分别为(138.848 0~277.696 0)×108 t,(3.967 6~7.935 2)×108 t、(2.793 6~5.587 2)×108 t和(0.825 1~1.650 2)×108 t。根据钴结壳的Co含量、Co通量和厚度相关分析,所赋予的钴结壳厚度占理论推测厚度的6.10%~12.20%,这与Ku等得出"钴结壳生长时间约占其整个生命史4%"的认识非常相近。三大洋海山钴结壳实测厚度与赋值厚度对比分析表明,太平洋海山钴结壳赋值厚度平均值为1.87cm,实测厚度平均值为1.77cm,相对误差为5.35%,大西洋和印度洋相对误差分别为18.18%和23.23%。研究数据表明按海山高度和洋壳年龄所赋的钴结壳厚度基本合理,估算出的钴结壳资源量基本可靠。本文首次估算出三大洋海山钴结壳资源量,为整个海盆和三大洋海山钴结壳资源量估算提供了新方法。 相似文献
16.
根据连续沥取实验结果及相关文献,富钴结壳的生长可用一个双阶段胶体-化学吸附模型来说明.第一阶段是混合胶体的形成及元素的清除与富集,富氧的底层水与缺氧、富Mn2＋的中层水体混合,Mn2＋被氧化而形成MnO2胶体,并与水柱中的Fe（OH）3、Al（OH）3、SiO2、Ti（OH）4等胶体形成多种混合胶体[MnO2-Fe（OH）3、Fe（OH）3-Ti（OH）4和Fe（OH）3-Al（OH）3-SiO2],后者根据各自的表面物理化学特征吸附和富集不同的元素;第二阶段是混合胶体的沉积及富钴结壳的生长,第一阶段形成的混合胶体在海山基岩上以氧化物或氢氧化物的形式沉积,吸附的元素结合进矿物点阵,然后通过自催化或自反馈的方式生长.在富钴结壳生长中,生物起着重要的作用,包括为富钴结壳的生长提供大量的成矿物质、对Mn2＋的催化氧化作用及在铁锰胶体的沉淀及富钴结壳壳层的生长过程中的媒介作用. 相似文献
17.
西太平洋Lamont海山中新世以来富钴结壳成矿环境的演化 总被引：5，自引：0，他引：5
分析了西太平洋Lamont海山12个站位33个富钴结壳样品的主元素和稀土元素,结果表明,该海山富钴结壳成因类型属于水成成因,并且在形成过程中基本未受到磷酸盐化作用的影响。Lamont海山的一个富钴结壳样品剖面的电子探针数据显示,该海山富钴结壳的成矿环境在新第三纪以来至少存在2个演化阶段:第1阶段,23~15 Ma,富钴结壳中Mn相对富集,成矿环境以富氧贫硅为特征;第2阶段,15~0 Ma,富钴结壳中Fe相对富集,成矿环境以贫氧富硅为特征。成矿环境的氧化能力总体上呈现下降的趋势。联系新生代世界大洋,尤其是西太平洋的地质演化背景,认为引起成矿环境演变的原因主要是西太平洋大洋板块的WNW向漂移和新第三纪以来全球水道开合,造成了Lamont海山所处海区最低含氧带逐渐减薄。 相似文献
18.
James R. Hein Ann E. Gibbs David A. Clague Michael Torresan 《Marine Georesources & Geotechnology》2013,31(2):177-203
This is the first article to describe mineralization of midplate submarine rift zones and hydrothermal manganese oxide mineralization of midplate volcanic edifices. Hydrothermal Mn oxides were recovered from submarine extensions of two Hawaiian rift zones, along Haleakala and Puna Ridges. These Mn oxides form two types of deposits, metallic stratiform layers in volcaniclastic rocks and cement for clastic rocks; both deposit types are composed of todorokite and bimessite. Thin Fe‐Mn crusts that coat some rocks formed by a combination of hydrogenetic and hydrothermal processes and are composed of δ‐MnO2. The stratiform layers have high Mn contents (mean 40%) and a large fractionation between Mn and Fe (Fe/Mn = 0.04). Unlike most other hydrothermal Mn oxide deposits, those from Hawaiian rift zones are enriched in the trace metals Zn, Co, Ba, Mo, Sr, V, and especially Ni (mean 0.16%). Metals are derived from three sources: mafic and ultramafic rocks leached by circulating hydrothermal fluids, clastic material (in Mn‐cemented sandstone), and seawater that mixed with the hydrothermal fluids. Mineralization on Haleakala Ridge occurred sometime during the past 200 to 400 ka, when the summit was at a water depth of more than 1,000 m. Hydrothermal circulation was probably driven by heat produced by intrusion of dikces, magma reservoirs, and flow of magma through axial and lateral conduits. The supply of seawater to ridge interiors must be extensive because of their high porosity and permeability. Precipitation of Mn oxide below the seafloor is indicated by its occurrence as cement, growth textures that show mineralizing fluids were introduced from below, and pervasive replacement of original matrix of clastic rocks. 相似文献
19.
为探究大洋富钴结壳的元素地球化学特征和赋存状态,以西太平洋麦哲伦海山群5个富钴结壳样品为研究对象,通过X射线衍射法、等离子体发射光谱法、等离子体质谱法及相态分析手段,分析了富钴结壳的矿物组成、主量元素和稀土元素含量。结果表明,富钴结壳样品主要结晶矿物为水羟锰矿,次要矿物包括石英、斜长石和钾长石,同时含有大量非晶态铁氧/氢氧化物。富钴结壳样品中Mn和Fe含量最高, Mn为16.87%～26.55%, Fe为14.34%～18.08%。富钴结壳明显富集稀土元素,其稀土总量为1 287～2 000μg/g,Ce含量为632～946μg/g,约占稀土总量的50%;轻稀土含量为1 037～1 604μg/g,重稀土含量为249～395μg/g,轻稀土元素明显高于重稀土元素。稀土元素配分模式呈现Ce正异常而Eu无异常,具有Ce富集特征。麦哲伦海山群富钴结壳是水成沉积成因,基本没有受到海底热液活动和成岩作用的影响。元素赋存状态与其矿物相密切相关, Na、K、Ca、Mg和Sr主要赋存于碳酸盐相, Mn、Ba、Co和Ni主要赋存于锰氧化物相, Fe、Al、P、Ti、Cu、Pb、V、Zn、Zr和REE主要... 相似文献
20.
Xiangwen Ren G. P. Glasby Jihua Liu Xuefa Shi Jingwu Yin 《Marine Geophysical Researches》2007,28(2):165-182
The internal structure and composition of a 37-mm-thick Co-rich Mn crust from the Lamont Guyot in the Marcus-Wake Seamount
cluster have been studied in detail by means of electron-probe microanalysis (EPMA). 184 point analyses for 16 elements were
carried out at an average spacing of 0.20 mm and each point was dated using the Co-geochronometer method. Two types of variation
in composition were observed in the crust: long-term trends and short-term erratic variations. The long-term trends were identified
using the fifth order polynomial. Mn and Ni were shown to increase in concentration from 23.3 Ma to a maximum at about 20 Ma
and then decline steadily to the Present, whereas Fe, P and Si showed the opposite trend. By contrast, Co displayed a double
humped pattern with maxima at about 19 Ma and 3.5 Ma and minima at 23.3 Ma, about 11 Ma and at Present. The long-term trends
in element concentrations in the crust lead us to suggest that much of the Fe in western Pacific Ocean ferromanganese crusts
is aeolian in origin and derived from the deserts of central Asia. Cooling of the Asian mainland at about 20 Ma led to an
increase in the flux of Fe to the oceans. This was supplemented by an additional input of Fe into the crusts as a consequence
of the dissolution of biogenic CaCO3 tests at 4.5−10.5 Ma. For the short-term erratic variations, three periods of 0.61, 0.96 and 1.65 m.y. were identified by
spectral analysis. The second harmonics of these periods are 1.22, 1.92 and 3.30 m.y., which may correspond to the highest-order
periods for eccentricity of 1.31, 2.04 and 3.47 m.y. This suggests the possibility that the high-frequency oscillations of
the time series data are linked to climatic changes controlled by the highest-order periods of the Milankovitch cycles. 相似文献