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1.
Fifty analyses of rare earth elements as well as mineralogical studies have been carried out on a suite of manganese nodules and crusts from the Central Indian Basin and the Western Indian Ocean. The aim was to identify the processes controlling the REE patterns of the phases hosting the REE in the manganese nodules, with an emphasis on an understanding of the Ce anomaly. This has involved separating the encrusting layers and nuclei physically as well as Fe-Mn oxides from the aluminosilicate phase chemically (using a 2 M HCl leach) prior to analysis.
The presence of nodule nuclei seems to have little influence (mostly <5% to a maximum of 30%) on the overall magnitude of the Ce anomalies in these nodules. The ratios of concentrations of elements in the acid leachates and the corresponding bulk values yield flat REE patterns indicating that the aluminosilicate phase contributes very little to the Ce anomalies. Interelement relations indicate that the Ce anomalies are largely controlled by the amorphous mineral phase FeOOH.xH2O. The relationship of Fe, Ce anomaly and δ-MnO2 further suggests that Ce is chemisorbed onto iron oxyhydroxides which are epitaxially intergrown with δ-MnO2.
The regional distribution of the Ce anomaly values appears to depend on many of the factors responsible for the uptake of other minor metals in nodules and crusts. 相似文献
2.
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
3.
北冰洋深海广泛分布的富锰棕色沉积层(棕色层)是海冰、洋流、物源供给等多种因素共同作用的结果，本文基于西北冰洋门捷列夫海岭ARC07-E25岩芯沉积物稀土元素与微量元素含量、颜色反射率参数、粗颗粒组分和无机碳含量的变化特征，对该类沉积层中稀土元素的组成特征、形成机制和物质来源进行了综合分析。结果显示，沉积物稀土元素总含量(∑REE)在122.37×10?6～231.94×10?6之间变化，北美页岩标准化配分模式显示出轻微的中稀土(MREE)富集以及由La、Ce、Nd主导的较强的轻稀土(LREE)优势。沉积物中∑REE随着粗组分颗粒(如冰筏碎屑)的增多而呈现降低趋势，表明门捷列夫海脊沉积物中的稀土元素主要富集在细粒沉积物中。根据∑REE在沉积物中的变化特征将E25岩芯沉积物划分为4种地层，反映出了冰期/间冰期的气候转变过程中温暖条件下形成的棕色层与寒冷条件下形成的浅灰绿色沉积层(灰色层)的岩性旋回中稀土元素组成的差异，由于两种沉积层在形成时受到不同的底层水氧化还原环境的控制，导致了铈(Ce)元素在氧化水体中会由Ce3+氧化为Ce4+并发生沉降，而在还原水体中则由Ce4+还原为Ce3+发生溶解，这一特性使LREE含量产生较大波动，进而影响到∑REE，使之趋于在代表氧化条件的棕色层中升高而在代表还原条件的灰色层中降低。R型因子分析和物质来源判别结果显示，E25岩芯沉积物中稀土元素与亲碎屑元素(Nb、U、Th)有较好的相关性，主要来源于东西伯利亚海和新西伯利亚群岛的近岸侵蚀物质以及勒拿河物质的输入。 相似文献
4.
P. Walter G. P. Glasby W. L. Plüger H. Kunzendorf M. A. Meylan 《Marine Georesources & Geotechnology》2013,31(3):321-337
Forty‐four sediment samples and 23 Mn crusts and Mn nodules have been analyzed for several elements in order to characterize their geochemical nature. Most of the Mn crusts and Mn nodules are of hydrogenous origin, although one crust (U375) from the flanks of the Rarotonga volcano is thought to be of hydrothermal origin. δ‐MnO2 is the principal Mn mineral in the crusts, whereas todorokite and birnessite occur in addition to δ‐MnO2 in the nodules. The sediments can be divided into carbonates, with calcite as the dominant phase, and deep‐sea clay, consisting mainly of illite and smectite. 相似文献
5.
Pavements of manganese nodules and crusts and outcrops of Miocene limestones were observed on the flanks and flat top of the Tenpo Seamount during three Shinkai 2000 dives. The pre‐Miocene volcano supplied nuclei of volcanic rocks and hydrothermal manganese deposits, and subsequent slow or no sedimentation promoted deposition of abundant hydrogenetic nodules and crusts, mainly on the upper flank of the seamount. Nodule pavements generally cover calcareous sand surface sediments, while crusts cover hard outcrops composed probably of volcanic rocks. The fields of crusts and nodules are sparsely distributed with each other on scales of meters to tens of meters. The on‐site observation suggests the deposits have encountered tectonic and/or mass movements that resulted in unusual occurrences of densely stacked nodules and occasionally the nodules resting directly on crusts or hard substrates. Mineralogical and chemical compositions reveal that for nodules and crusts the encrusting manganese layers of around 1 cm thickness are composed of hydrogenetic vernadite, and diagenetic influence is negligible. 相似文献
6.
于1987年5—6月间,中、西德在南海进行地球科学调查,获得5个铁锰结壳、6个铁锰结核样品。本文在利用X荧光法测定15个稀土元素的基础上,对南海铁锰结核(壳)的稀土丰度、配分模式与伴生元素的关系以及稀土的来源作了较为详细的探讨。研究表明,南海铁锰结核(壳)的平均丰度为1625×10~(-6),铁锰结核为2167×10~(-6),分别要比太平洋结核高1—2倍,比太平洋北部沉积物高3—4倍,比南海沉积物高10—20倍;结核和结壳的稀土经球粒陨石标准化后的配分模式基本相同,Ce正异常,Eu亏损不明显;与伴生元素、沉积物及岩石稀土对比研究表明,结核(壳)中稀土主要来自南海中酸性岩类风化、淋漓后缓慢沉积。 相似文献
7.
ＲＥＥｄｉｓｔｒｉｂｕｔｉｏｎｉｎｗａｔｅｒ－ｓｅｄｉｍｅｎｔｉｎｔｅｒｆａｃｅｓｙｓｔｅｍａｔｄｅｅｐｏｃｅａｎｆｌｏｏｒ￥ＺｈａｎｇＬｉｊｉｅ；ＬｉｕＪｉｈｕａａｎｄＹａｏＤｅ（ＲｅｃｅｉｖｅｄＦｅｂｒｕａｒｙ１，１９９４；ａｃｃｅｐｔｅｄＭａｙ... 相似文献
8.
Rare earth elements-rich phase and enriching mechanism in sediments from CC area, the Pacific Ocean 总被引：1，自引：0，他引：1
Compared to North American shale composition (NASC),REE contents of sediments from the CC area in the Pacific Ocean are obviously high except that cerium has equal content to that of NASC.Three-valence rare earth elements were completely enriched in phosphate-phase and cerium in iron-phase.Rare earth elements in the sediments were originally derived from seawater.During lithigenic and minerogenic processes of metalliferous nodules,three-valence rare earth elements in sediments mobilized and incorporated into sediments as authigenous biogenic-apatite,while cerium had change from Ce3+ to Ce4+ and directly precipitated from seawater and entered metalliferous nodules and caused Ceanomalies in REE pattern in sediments. 相似文献
9.
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
10.
11.
P. Stoffers G. P. Glasby D. Stuben R. M. Renner T. G. Pierre J. Webb 《Marine Georesources & Geotechnology》2013,31(1):45-86
Abstract Hydrothermal iron‐rich crusts have been recovered from a number of hot spot volcanos including Crough Seamount, Pitcairn Volcanos 2 and 1, Cyana Seamount, Teahitia, Moua Pihaa, and Macdonald Seamount in the S. W. Pacific. Mineralogically, the crusts consists of ferrihydrite with traces of the weathering products of volcanic ash (feldspar, nontronite, pyroxene, and serpentinite). The iron oxyhydroxide phase has a mean particle size of 3–4 nm indicating rapid deposition. Electron microprobe studies have revealed the presence of filamentous iron‐silica deposits within the crusts reflecting the possible bacterial oxidation of iron from the hydrothermal fluids. The crusts display wide variability in composition both between individual sampling stations and between seamounts. Endmember analysis shows that the compositional data can be resolved into three endmembers: a Fe‐rich endmember, a light and heavy rare earth element endmember, and a Ba (barite)‐rich endmember. The Fe‐rich endmember appears to contain very low concentrations of most trace elements. For bulk samples, the composition of the iron‐rich crusts reflects dilution of the iron oxyhydroxide phase by volcanic ash and, to a lesser extent, a hydrogenous component. This is illustrated by the wide variability in SiO2 (11.1–71.3%) and Mn (0.01–1.21%) contents of the crusts. For iron‐rich crusts containing greater than 40% Fe, the Pitcairn crusts display lower contents of Pb, Ba, Mo, U, Th, As, and rare earth elements (REE) and lower cerium anomalies than those from Teahitia. REE profiles of crusts from each of the hot spot volcanoes are characterized by small negative cerium anomalies but pronounced positive europium anomalies. The low average La/Fe ratios of the crusts from the various seamounts (47–572 X 10‐6) and positive Eu anomalies of the crusts suggest rapid deposition of the iron oxyhydroxide near the hydrothermal vent. The high Fe/Mn ratio of vent fluids at hot spot volcanoes (8.5–5.6) may account for the formation of these iron‐rich crusts. The present data indicate that there may be differences in the nature of the iron‐rich crusts based on the depth of occurrence. This influences the temperature of the venting hydrothermal fluids and the possibility of occurrence of submarine phreatomagmatic eruptions. 相似文献
12.
Geochemistry of trace elements and Sr-Nd isotopes of foraminifera shell from the Okinawa Trough 总被引：1，自引：0，他引：1
ＩＮＴＲＯＤＵＣＴＩＯＮＰｒｏｖｅｎａｎｃｅｏｆｍａｒｉｎｅｓｅｄｉｍｅｎｔｓｈａｓａｌｗａｙｓｂｅｅｎａｆｏｃｕｓｅｄｐｒｏｂｌｅｍｉｎｍａｒｉｎｅｓｅｄｉｍｅｎｔｇｅ ｏｌｏｇｙ.Ｒｅｃｏｇｎｉｔｉｏｎｏｆｅｎｄｍｅｍｂｅｒｓａｎｄｅｓｔｉｍａｔｉｏｎｏｆｔｈｅｉｒｒｅｌａｔｉｖｅｐｒｏｐｏｒｔｉｏｎｓｆｒｏｍｍｉｘｅｄｓｅｄｉｍｅｎｔｓｈａｖｅｂｅｅｎａｋｅｙｃｏｎｔｅｎｔｉｎｔｈｅｓｔｕｄｙｏｆｐｒｏｖｅｎａｎｃｅ .Ｆｏｒｔｈｉｓａｉｍ ,ｉｔｉｓｎｅｃｅｓｓａｒｙｔｏｓｅｌｅｃｔｅｎｄｍｅ… 相似文献
13.
冲绳海槽有孔虫壳体的微量元素Sr,Nd同位素地球化学 总被引：6，自引：1，他引：6
钙质生物壳的微量元素组合和Sr,Nd同位素组成是识别海底混合源沉积物中生物源物质相对贡献的重要参数.冲绳海槽有孔虫壳体强烈富集Sr,P,Mn和Ba,富集Li,U,Th,Sc,Co,Pb,Zn,Cr,Rb,Y,Sb和轻稀土元素,弱富集V,Ga,Zr,Nb,Cd和中稀土元素,相对贫Ge,Mo,In,Sn,Cs,Hf,Ta,W,Tl,Bi和重稀土元素,海水中微量元素的背景含量和生物活动对微量元素的选择性吸收是有孔虫壳体中微量元素发生富集和贫化的主要机制,冲绳海槽有孔虫壳体的稀土元素配分模式与海水和太平洋有孔虫的有明显差异,表现出中稀土元素相对富集,并具有微弱的负Ce异常.有孔虫壳体的Sr,Nd同位素比值也与大洋海水不同,分别为0.709769和0.512162,前者略高于大洋海水,后者略低于大洋海水,表明冲绳海槽海水明显受大陆河水影响. 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.
ZHONG Yi CHEN Zhong GONZALEZ Francisco Javier ZHENG Xufeng LI Gang LUO Yun MO Aibin XU Antao WANG Shuhong 《海洋学报(英文版)》2018,37(7):41-54
Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements(REE) and yttrium(REY),with a growing interest in exploitation as an alternative to land-based REY resources.On the basis of comprehensive geochemical approach,the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed.The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity.Total REY contents range from 69.1×10~(–6) to 2 919.4×10~(–6),with an average value of 1 459.5×10~(–6).Especially,the enrichment rate of Ce content is high,accounting for almost 60% of the total REY.This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts.Moreover,the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin.Finally,Light REE(LREE) and heavy REE(HREE) oxides of the ferromanganese deposits in the study area can be classified into four grades: non-enriched type,weakly enriched type,enriched type,and extremely enriched type.According to the classification criteria of rare earth resources,the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals. 相似文献
16.
南海尖峰海山多金属结壳地球化学 总被引：4，自引：5，他引：4
南海尖峰海山多金属结壳富含30多种元素,其锰铁矿物主要由钡镁锰矿,δ-MnO_2和FeOOH·xH_2O组成。与其它海区的结壳相比,尖峰海山结壳富含Cu、Ni、Ba、Zn、Pb等元素,而Co、Ti、稀土元素(REE)、Sr等元素相对较贫。研究表明,HREE亏损,具明显的Ce正异常,较明显的Tb正异常和Yb负异常。这是氧化弱碱性海洋环境所致。结壳是水成作用的产物,它的形成受南海独特的古海洋环境所控制,海底火山热液作用,可能也是影响因素之一。 相似文献
17.
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
18.
J. N. Pattan Ch. M. Rao A. A. Migdisov S. Colley N. C. Higgs L. Demidenko 《Marine Georesources & Geotechnology》2013,31(3):155-165
Abstract The rare earth element (REE) distribution in nine deep-sea ferromanganese nodules and their associated siliceous sediments from the Central Indian Ocean Basin (CIOB) have been studied to elucidate the REE relationship among them. Total REE concentration varies from 398–928 ppm in the nodules and 137–235 ppm in the associated sediments, suggesting two- to four-fold enrichment in the nodules compared to associated sediments. REE of nodules and their associated sediments show a positive correlation, suggesting REE are supplied from a common source such as seawater. The positive correlation between REE of nodules and sediments from the CIOB is contrary to the competitive scavenging of REE between nodules and sediment in the equatorial Pacific Ocean. REEs in the nodules are carried by Fe, P, and Ti, whereas in the sediment they are carried by P and Mn phases. A similar REE fractionation pattern with middle REE enrichment over heavy and light REE in both the nodules and their associated sediment suggest fractionation is independent of REE abundance and their carrier phases. 相似文献
19.
Using a neutron activation analysis technique, which involves gamma-spectrometry with a Ge(Li) detector coupled to a S40 multichannel analyzer and interfaced to a PDP-11 computer, we determined thirty-eight elements in sediments from the lower reach (downstream from Jinan) and estuary of Huanghe. The results are discussed in this paper.From inter-elemental correlations, it ts found that a large number of metals (Mn.As, Co, Cr.Cs, Rb, Sc, Ti, Ta, V and Zn) correlate positively with Fe. Ba and Ca correlate positively with Al. Whereas some elements (e. g. , Ti and lanthanides) show no correlation with either Fe or Al. On the other hand, Hf and Zr show a negative correlation with Fe. Elements which tend to be scavenged by Fe and Al colloids or suspended particles are enriched in sediments at the Huanghe Estuary relative to its lower reach. On the other hand, the contents of some elements (e. g. , Zr,Hf,U, Ba, etc. )are higher in sediments from the lower reach of Huanghe than in the estuarine sediments,which 相似文献
20.
The elemental composition of ferromanganese sedimentary structures from the bottom of Lake Baikal represented by nodules and
crusts, as well as the enclosing sediments, have been studied by the atomic absorption, chemical, and ICP-MS methods. It is
established that the contents of the rock-forming and accompanying elements in them are highly variable. In this connection,
the examined samples are divided in two groups differing by their Mn/Fe values. In most of the samples, they range from 0.01
to 0.1, although some of the ferromanganese structures or their parts are substantially enriched in manganese. The contents
of most of the rare and dispersed elements in the ferromanganese structures are usually at the background level, although
the samples maximally enriched in iron or manganese are characterized by relatively high copper, nickel, cobalt, vanadium,
zinc, and molybdenum concentrations. 相似文献