深海沉积物分类与命名

详细分析了国内外深海沉积物分类与命名现状,迄今为止深海沉积物分类与命名问题没有很好解决。在调查研究南海、太平洋深海沉积物分类与命名基础上,提出了分类简便、科学合理、量化的深海沉积物分类与命名新方法,应用该方法得出南海东部海域深海沉积物有深海粘土、硅质粘土、钙质粘土、硅钙质粘土、钙质软泥、粘土质钙质软泥、粘土质-硅质钙质软泥、粘土-硅质-钙质混合软泥、粘土质硅质-钙质混合软泥、钙质硅质-粘土混合软泥。这10种沉积物基本上客观地反映了南海东部海域深海沉积物分布的实际情况,分类效果良好。     

印度洋钙质软泥和硅质软泥稀土元素组成和富集机制

本文针对采自印度洋深海中最常见的两类生物成因沉积物——钙质软泥和硅质软泥，开展了全岩样和不同粒级组分中常微量元素、稀土元素和Y（REY）含量的系统分析，探讨了两类沉积物中REY的组成特征、物质来源和富集机制。研究表明，钙质软泥以富含CaO和Sr为主要特征，硅质软泥则富集SiO₂、Al₂O₃、Fe₂O₃等。钙质软泥中∑REY平均含量为40.56×10-6，轻稀土元素（LREE）略有富集，REY有向细粒沉积物中富集的特征，PAAS标准化后全岩样和不同粒级组分均表现为Ce负异常、Eu和Y正异常；REY以自生来源为主，继承了海水的组成特征，同时也受到了热液流体物质和洋底玄武岩风化产物的影响。硅质软泥中∑REY的含量为248.54×10-6，LREE相对富集，REY在4φ以细的沉积物中富集；研究站位沉积物中∑REY含量处于边界品位附近，但在细粒级沉积物中重稀土元素（HREY）含量则达到了工业品位；该类沉积物细粒组分中REY主要来自陆源或火山碎屑组分中黏土矿物和铁锰氧化物吸附作用，粗粒组分中REY来源则主要与生物作用相关；硅质软泥中REY的富集与沉积物中磷灰石等矿物相关，部分不同来源的REY可能是在沉积之后的成岩过程中再次分配向磷灰石、钙十字沸石等矿物中富集。     

In Memoriam

Abstract

The engineering properties of deep continental margin sediments were determined on a worldwide basis. Deep Sea Drilling Project (DSDP) core data and material were utilized from over 900 cores obtained from 89 sites, primarily on the continental margins. Cores were recovered from penetrations to 200 m in water depths averaging 3000 m. Supplementary laboratory testing on selected cores was directed toward determining index properties and shear strength properties of the sediments. The study included a literature review of deep‐sea soil properties, the results of which are to be used by DSDP to evaluate foundation conditions for reentry cones with long casing strings. The results will also be used for a feasibility study of an ultradeepwater marine riser and well‐control system. The marine sediments examined can be divided into three main types: clay, calcareous ooze, and siliceous ooze. Sediment distribution consisted of 48% calcareous ooze, 43% clay, 6% siliceous ooze, and 3% volcanic ash. Because of the sample disturbance inherent in the deepwater coring operation, emphasis was placed on analyzing sediment properties not significantly affected by changes in in situ stresses and structure caused by sampling. Averages and ranges in values of water content and unit weight are presented for the three main sediment types. Plasticity and strength characteristics are discussed in detail and the elastic and compression properties are outlined. The geotechnical properties of deep continental margin soils are summarized.     

Distribution pattern and morphochemical relationships of manganese nodules from the Central Indian Basin

In the Central Indian Basin manganese nodule abundance was variable in all sediment types. Mean abundance varied from 1.5 in calcareous ooze to 10.2 kg/m² in terrigenous-siliceous ooze sediments. Nodule grade and growth rates are positively correlated only up to 10 mm/My (million years), and grade shows no distinct relationship with abundance. Relationships between the morphochemical characteristics of the nodules and host sediment types are subtle. Both hydrogenetic and diagenetic nodules (with smooth and rough surfaces respectively) occur on almost all sediments, but in variable proportions. Thus, the overall distribution pattern shows that small nodules (<4-cm diameters) of lower grade (average value Ni+Cu+Co=1.21%) with smooth surfaces are more common on red clay, terrigenous, and terrigenous-siliceous ooze transition-zone sediments. By contrast, large nodules (>4-cm diameters) of higher grade (average value Ni+Cu+Co=1.80%) with rough surfaces are more prevalent on siliceous ooze, siliceous ooze-red clay, and calcareous ooze-red clay transition-zone sediments. This implies an enhanced supply of trace metals from pore waters to rough-surface nodules during early diagenesis.     

东太平洋CC区西区表层沉积物黏土矿物和地球化学特征

本文以太平洋CC区西区12个表层沉积物样品作为研究对象,对其粒度、化学组分和矿物成分进行分析,讨论其沉积环境和物质来源。研究区地处深海,主要以深海黏土和硅钙质黏土为主,含有少量的硅质黏土、黏土质硅质软泥和黏土质钙质软泥。黏土矿物成分主要是蒙皂石和伊利石,含有部分的高岭石和绿泥石。黏土矿物组成表明,区内沉积物主要是陆源,由高空气流携带而来,南极底流和热液活动对其物源的来源有一定影响。沉积物地球化学特征也表明,物源以陆源为主,稀土元素分布曲线和北太平洋表层海水稀土曲线类似,且表现出强的Ce亏损,表明生物活动导致的生物沉降对表层沉积物也有一定的影响。     

南海东部海域表层沉积物类型的研究

南海东部海域表层沉积物可被分为11种类型:含岩块砾石黏土质粉砂、贝壳珊瑚砂、黏土质粉砂、钙质黏土、钙质软泥、有孔虫砂、深海黏土、含铁锰微粒粉砂质黏土、硅质黏土、含火山灰硅质黏土、含火山灰粉砂质黏土.这些类型按物源和成因可被分为陆源碎屑、钙质碎屑和硅质碎屑、火山碎屑3大类型,其中陆源碎屑分布面积约占50%,钙质碎屑占20%,硅质碎屑和火山碎屑各占15%.在物质来源、海底地形、火山作用、生物作用、水动力条件等因素影响和控制下,由于沉积环境的差异,故区内褐色类沉积物最多(60.68%),灰色类沉积物次之(38.20%),黄色类沉积物最少(1.12%).台湾省以南到17°N以北海区沉积物以陆源沉积物分布为主;巴士海峡以西海区沉积物较粗,常含砂岩块和砾石;东沙群岛以东海区钙质生物碎屑沉积丰富;中、西部海区以含铁锰微粒沉积物为主;中、南部海区水深大,主要分布硅质沉积物;南部海区、礼乐滩北缘沉积物受礼乐滩珊瑚碎屑影响大,沉积物类型为钙质软泥.     

Major,Trace, and Rare Earth Elements in the Sediments of the Central Indian Ocean Basin: Their Source and Distribution

Abstract

A large number of surface sediments as well as short sediment cores collected in the Central Indian Ocean Basin have been subjected to various geochemical investigations during the last one and half decade. The studies varied, covering different aspects of sediments and resulting in a number of publications. In the present article, we have put together the data from 82 surface sediments and 14 short sediment cores, including 25 new analyses, to study the trend of their distribution and source at large. The distribution maps of elements show that highest concentrations of Mn, Cu, Ni, Zn, Co, and biogenic opal in the surface sediment occurs between 10°S and 16°S latitude, where diagenetic ferromanganese nodules rich in Mn, Cu, Ni, and Zn are present. The studies highlight that the excess element concentration (detrital unsupported) such as Mn, Cu, Ba, Ni, Co, Pb, and Zn have contributed >80% of their respective bulk composition. These excess elements exhibit strong positive correlation with each other suggesting their association with a single authigenic phase such as Mn oxide. Biogenic opal contributes 30–50% of the total silica in the siliceous sediment. Aluminum, Fe, and K have contributed >60% from terrigenous detrital source compared to their bulk composition. In calcareous ooze, Ca, and Sr excess contribute >95% while, in siliceous ooze it is only 50% of their bulk composition. Nearly 35% of structurally unsupported Al in the sediment raises doubt of using Al as a terrigenous index element to normalize the trace and minor elements. Biogenic apatite is evident by the positive correlation between Ca (<1%) and P. Calcium, Sr, and P depict a common source such as biogenic. Bulk element concentration such as Li, V, Cr, Sc, and Zr are positively correlated with Ti indicating their terrigenous detrital source. Rare earth element (REE) concentration increases from calcareous ooze to siliceous ooze and reaches a maximum in the red clay. Presence of positive Eu-anomaly in these sediments has been attributed to aeolian input. REE in these sediments are mostly carried by authigenic phases such as manganese oxide and biogenic apatite. Based on the distribution of transition elements in the sediment cores, three distinct zones—oxic at top, suboxic at intermediate depth, and a subsurface maxima—have been identified. Oxic and suboxic zones are incidentally associated with high and low micronodule abundance in the coarse fraction (>63 μm) respectively. Ash layers encountered at intermediate depth between 10 to 35 cm are correlative with the Youngest Toba eruption of ～74ka from Northern Sumatra. This ash is mainly responsible for the high bulk Al/Ti ratio up to 48.5 (three times higher than Post Archean Australian Shale), other than scavenging of dissolved Al by biogenic components.     

西太平洋E20岩芯末次冰期以来的沉积特征与环境意义

硅藻席沉积在热带西太平洋陆续被发现,其形成年代和机制对于热带西太平洋碳循环研究具有重要意义。本文对采自西马里亚纳弧,含近2.5 m厚硅藻席沉积的E20岩芯进行了高分辨率的XRF元素扫描、颜色扫描以及AMS14C测年分析。结果表明,E20可分为3个沉积单元,从下至上具有深海黏土—硅质软泥—硅质黏土的沉积序列,Ti、Fe、Cu、Br等元素呈三段式变化,Ca与Si元素呈反向变化。综合AMS14C测年结果推测,E20反映了西太平洋低纬度海区末次冰期以来显著的环境变化,10.9～28.6 ka B.P.为硅藻席勃发期,而末次冰期时风尘输入量的增加可能是勃发的主要原因。硅藻席沉积的保存与其周围的围陷地形有很大关系。     

中太平洋海盆表层沉积物类型及其主要受控因素

本文通过对中太平洋海盆４０多个表层沉积物的分析和研究，根据沉积物中各组分含量、物质来源和成因等特征，把本区表层沉积物分为六种类型。它们分布在不同区域和不同水深范围内。钙质沉积物分布在碳酸钙补偿深度（ＣＣＤ）界面以浅区。硅质粘土、深海粘土等沉积物出现在ＣＣＤ以下水深区，这些沉积物的分布具有明显的垂向分带性和横向分区性。沉积物类型的变化主要受水深与物质来源的控制，南极底层流也有一定的影响。在不同的沉积物中锰结核的丰度、品位、类型等亦有明显的差异。     

东太平洋中国开辟区环境调查区的沉积物及其与环境关系

以生态环境为主的环境基线调查, 是与深海采矿有关的研究内容之一, 它对保护海洋自然环境有着重要的意义, 而环境小区沉积物的分析研究是其中一个不可缺少的环节。通过对东太平洋中国开辟区内沉积物类型与碎屑成分特征的研究表明, 该区表层沉积物基本上是硅藻放射虫软泥, 个别站和层位是硅质粘土和深海粘土。碎屑物成分以放射虫壳体占绝对优势。它们以大洋生物源为主体,火山喷发源和陆源为次。沉积物组分构成特点同海洋环境密切相关。上述结果为地球化学、生物学和土力学等综合研究提供了基础资料, 并有助于了解开辟区本底环境的变化。     

Hydrothermal Mineralizing Processes and Associated Sedimentation in the Santorini Hydrothermal Embayments

Seven sediment cores from the Palaea and Nea Kameni hydrothermal embayments (PK and NK) on Santorini have been studied by using sediment smear slides, X-ray diffraction, and radiocarbon techniques to determine their lithology, mineralogy, and age, respectively. The cores have been analyzed chemically for a suite of elements, including selective chemical leaching, to determine the partition of elements between coexisting phases. Lithologically and chemically, the sediments from the two embayments are very different. Sediments from PK are oxidized in the upper parts of the cores and reduced at depth; they comprise mainly hydrothermal pyritiferous diatomaceous ooze with minor Fe oxyhydroxide, volcanic debris, gypsum, and siderite. Sediments from NK are oxidized throughout and comprise predominantly amorphous iron oxyhydroxides and goethite; they are thought to have formed by direct precipitation from solution. In PK, biogenic, detrital seawater evaporate, and hydrothermal sediment phases have been identified but only the detrital inputs can be correlated between cores. Mn shows a pronounced enrichment towards the outer part of the embayment because of its dispersion down the embayment and precipitation in the more-oxidizing sediments towards the open sea. In NK, the sediments contain detrital, seawater evaporate, and hydrothermally precipitated and scavenged phases. The presence of substantial amounts of organic matter in the PK sediments but not in the NK sediments is probably the main reason why geochemical processes in the two embayments are different. Age dates obtained from the cores by using the 14 C technique indicate that sedimentation in the PK embayment commenced at approximately 50 AD, whereas in the NK embayment it commenced at approximately 1900 AD, which is consistent with the known history of Santorini. Based on these dates, calculated metal accumulation rates in both embayments are higher than in any other dated hydrothermal metalliferous sediments with the exception of those in the Atlantis II Deep of the Red Sea. Sediment ponding in the embayments is the principal cause of these results.     

Hydrothermal Mineralizing Processes and Associated Sedimentation in the Santorini Hydrothermal Embayments

Abstract

Seven sediment cores from the Palaea and Nea Kameni hydrothermal embayments (PK and NK) on Santorini have been studied by using sediment smear slides, X-ray diffraction, and radiocarbon techniques to determine their lithology, mineralogy, and age, respectively. The cores have been analyzed chemically for a suite of elements, including selective chemical leaching, to determine the partition of elements between coexisting phases. Lithologically and chemically, the sediments from the two embayments are very different. Sediments from PK are oxidized in the upper parts of the cores and reduced at depth; they comprise mainly hydrothermal pyritiferous diatomaceous ooze with minor Fe oxyhydroxide, volcanic debris, gypsum, and siderite. Sediments from NK are oxidized throughout and comprise predominantly amorphous iron oxyhydroxides and goethite; they are thought to have formed by direct precipitation from solution. In PK, biogenic, detrital seawater evaporate, and hydrothermal sediment phases have been identified but only the detrital inputs can be correlated between cores. Mn shows a pronounced enrichment towards the outer part of the embayment because of its dispersion down the embayment and precipitation in the more-oxidizing sediments towards the open sea. In NK, the sediments contain detrital, seawater evaporate, and hydrothermally precipitated and scavenged phases. The presence of substantial amounts of organic matter in the PK sediments but not in the NK sediments is probably the main reason why geochemical processes in the two embayments are different.

Age dates obtained from the cores by using the ¹⁴C technique indicate that sedimentation in the PK embayment commenced at ～ 50 AD, whereas in the NK embayment it commenced at ～ 1900 AD, which is consistent with the known history of Santorini. Based on these dates, calculated metal accumulation rates in both embayments are higher than in any other dated hydrothermal metalliferous sediments with the exception of those in the Atlantis II Deep of the Red Sea. Sediment ponding in the embayments is the principal cause of these results.     

中印度洋海盆富稀土沉积地球化学特征及富集机制研究

本文对中印度洋海盆深海富稀土沉积区两根柱样GC02和GC06开展了沉积物涂片观察,X-射线衍射分析,主量、微量和稀土元素分析,以及单矿物原位微区地球化学分析等,探讨了其地球化学特征、物质来源及稀土元素（REY）的富集机制。结果表明,GC02柱状沉积物类型为钙质黏土和沸石黏土,GC06柱状沉积物类型为钙质黏土、含沸石黏土和沸石黏土。稀土元素主要在含沸石黏土和沸石黏土中富集。北美页岩标准化（NASC）配分模式指示沉积物的REY主要来源于海水,矿物学和地球化学等特征表明该地区沉积物陆源组分可能主要源于澳大利亚的风尘物质。元素相关性和CaO/P₂O₅比值等指示了深海富稀土沉积中REY的主要赋存矿物为生物磷灰石（鱼牙/骨等）,其次为铁锰微结核。本文总结和探讨了深海富稀土沉积的形成机制,完善了深海富稀土沉积形成过程的概念模型。     

冲绳海槽中西部边缘区沉积物成因和沉积环境

本文根据１９９６年“中－法合作东海计划”在冲绳海槽中西部边缘区所取柱状样岩芯沉积物粒度分析资料,对该区沉积物特征进行研究。结果表明,火山沉积和富含生物的半远洋深海软泥沉积是本区的主要特征。以４８１ｃｍ为界,上、下两层沉积物截然不同,可能是沉积物的来源不同或者是水动力条件的差异。该区主要受火山活动的影响,其次是黑潮、大洋风暴     

太平洋东部CC48孔沉积物稀土元素地球化学研究

研究样品于１９８８年采自太平洋东部ＣＣ４８孔。通过对沉积物稀土元素地球化学特征的分析发现：（１）各种类型深海沉积物的稀土含量有所差别，以稀土元素总量而论，深海粘土＞硅质软泥＞硅钙质软泥＞钙质软泥；沉积物中的自生矿物、硅质生物成因的非晶质ＳｉＯ２及碎屑矿物对稀土元素起富集作用，而生物ＣａＣＯ３则起分散作用。（２）稀土元素含量随深度发生变化。为地层划分提供了依据，应用元素地层学方法将岩芯分成５个层段。     

Holocene environmental change and the accumulation–erosion balance of sheltered river-mouth sediments, Göteborg, SW Sweden

Holocene sedimentological change was investigated in 15 sediment piston cores (250 cm long) from the mouth of the Göta älv River, outside of Göteborg, which is sheltered by an archipelago. The main objective was to interpret recent, natural and human-induced influences upon the accumulation–erosion balance and the sedimentary environment from Holocene sediment units. The five main units are: consolidated glaciomarine clay (Facies gC) lowermost, consolidated estuarine clay (Facies dC), soft sub-recent sediment (Facies omC and Facies C) uppermost and dumped sediment (Facies D) in some parts of the study area. The sediment facies are divided by two major hiatuses: (a) the early Holocene hiatus between Facies gC and dC involves a time gap of at least 7000 years, ending at ca. 4000 BP and (b) the late Holocene hiatus between the consolidated clays (Facies gC and dC) and Facies omC spans 1000 years and ends ca. 50 BP (i.e. 100 years ago). Both hiatuses probably relate to the effects of isostatic land uplift. Surface sediments consist mainly of an organic-matter-rich clay facies, suggesting changes in the trophic state of the estuary during the last 100 years. Together with human-induced increased river erosion and loss of accommodation space in the estuary, this caused the onset of sedimentation in the estuary. The recent sediments are contaminated with heavy metals (Cu, Zn, Pb, Hg), with highest concentrations in the lower part of Facies omC.     

The stratigraphic and geographic distribution of giant craters and remobilised sediment mounds on the mid Norway margin,and their relation to long term fluid flow

Large craters associated with mounds of remobilised sediment have been recently mapped on the mid Norway margin in the Møre Basin. These craters and mounds may be linked to the long term migration of fluids upwards from the lower levels of the Møre Basin which exploit hydrothermal vent complexes emplaced in the late Paleocene and early Eocene. All of the craters are located on a regionally correlative seismic surface that is correlated with the basal shear plane of Slide W, a slide located at the base of the Plio-Pleistocene Naust Formation. The Craters are positioned in the western area of the Møre Basin at the foot of the continental slope on the crests and flanks of Miocene domes, where Oligocene biosiliceous ooze subcrops on the basal shear surface of Slide W. Not all of the craters are filled by Slide W. Mounds are emplaced above those craters which are filled by Slide W on the top surface of Slide W. Stratal relationships show that the mounds were emplaced on the paleo-seabed. We present and discuss two models that illustrate processes that may have been involved in the formation of craters and remobilisation of sediments. In one model, an eruption of fluid from beneath remobilises ooze into ooze mounds in a single event triggering slope failure, whereas in the other model the emplacement of Slide W and later slides loads low density ooze causing it to undergo liquefaction, a process which may have been facilitated by the trapping of continuous long term fluid migrating from beneath, causing the ooze to remobilise into ooze mounds in two or more events.     

Contrasting trace element geochemistry in two American and French salt marshes

Trace metals were analyzed in the bulk fine phase of two contrasting salt marsh cores on the North Atlantic east (Baie de l'Aiguillon, LaRochelle, France) and west (Lewes, DE, USA) coasts. The purpose is to gauge how the different clay mineral sources and surface sedimentary diagenetic conditions affect the respective trace element geochemistries. It has been established that there is considerably more clay mineral diagenesis at the zone of redox transition in the Delaware core than in the l'Aiguillon core. The Delaware core shows unweathered glacial sedimentary material directly deposited from the continental shelf whereas the l'Aiguillon core is formed from soil clays deposited after river and estuarine transport. Although there is strong Mn redox depletion in the Delaware salt marsh core, and enrichment in the French one at l'Aiguillon, transition elements seem to follow iron content in both cores. The trace pollutant elements Pb, Sn and Zn show pronounced depth profiles in both North Atlantic cores. The Pb, Sn and Zn appear to be carried by clay sources into the French marshes, while appearing to be largely deposited by atmospheric processes as well into the Delaware marsh.Upon deposition, the Zn appears to become decoupled from lead, which is probably more strongly fixed on clays. The Sn seems to be both air transported, and carried as well on non-clay phases contaminated by industrial organo-tins, including antifouling bottom paints. Copper while uniformly enriched in France, probably from use in regional vineyards, appears enriched only near the top at Delaware, suggesting diagenetic recycling in the more abundant peat in the surface. The Cs and Li appear to be tracers for specific soil-derived clay sources in the French core source materials. These observations suggest that clay is a very important carrier in fixing trace elements for historical records as salt marsh sediments.     

基于PXRF的西南印度洋脊硫化物表层沉积物地球化学找矿研究

海底热液喷发形成的热液羽状流中富含成矿物质,并沉淀在距离热液喷口不等的范围内。对西南印度洋中脊热液喷口附近、距离喷口中等距离、远离喷口的六个表层沉积物样品开展了不同粒度沉积物的便携式XRF（PXRF）分析。结果表明,PXRF可以有效获得的洋中脊钙质沉积物中成矿元素的富集特征。>40目的沉积物样品具有较高的Cu、Zn、Fe、Mn等元素含量,40目以下沉积物中则相对稳定,可能与粗粒沉积物中玄武岩碎屑/玻璃含量较高有关,与镜下鉴定结果一致。以热液喷口为中心,表层沉积物中表现出Cu、Zn、As、Fe、Mn的元素分带,靠近喷口的沉积物中具有较高的成矿元素的含量,并具有较高的Cu/Fe、Zn/Fe比值或者Cu/Mn与Zn/Mn比值。上述结论表明,洋中脊沉积物中成矿元素的含量主要受与喷口的距离的影响,而与粒度的关系不大,洋中脊沉积物地球化学找矿应采用40目以下粒径沉积物作为分析样品。通过PXRF获得的Cu、Zn、As、Fe、Mn等元素含量及其比值特征可以作为海底多金属硫化物沉积物地球化学找矿的指标,该方法满足快速有效识别洋中脊沉积物中地球化学异常的要求。     

中太平洋西部海底沉积物孢粉分析与C14年代测定

1978年12月-1979年8月,我国参加了世界气象组织主办的“第一次全球大气试验”.其间,我国科学考察船在中太平洋西部海域进行了海底沉积物调查研究工作.