西太平洋多金属结核区表层沉积物细菌群落结构及其对沉积扰动的响应          下载免费PDF全文

王苑如  崔鸿鹏  李继东  孙栋  王春生  杨娟 《海洋学研究》2021,39(2):21-32

本文基于大洋第48航次在西太平洋马尔库斯 威克海山多金属结核区采集的6个表层沉积物样品的高通量测序结果,开展底栖细菌群落结构调查,共获得253012条序列,分属于41个门、85个纲、189个目、261个科和322个属。其中,变形菌纲(Proteobacteria)为优势类群,分为γ 、α 和δ 三个亚群,分别占总序列条数的24.76%、20.21%和6.48%。绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)、芽单胞菌门(Gemmatimonadetes)、浮霉菌门(Planctomycetes)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)及硝化螺旋菌门(Nitrospirae)等类群的序列数和属种较丰富。对序列条数大于1%的OTU(operational taxonomic units)分析,共获得优势菌群23个目,包含6个优势科,10个优势属,其中,铁锰功能细菌占10.20%,主要来自交替单胞菌属(Alteromonas)(6.90%)、假交替单胞菌属(Pseudoalteromonas)(1.80%)和希瓦氏菌属(Shewanella)(1.00%)等,另外还存在参与氮和硫元素循环的种属。PICRUSt功能预测分析显示结核区细菌主要涉及信号转导、蛋白转运、原核生物固碳、群体感应、能量转换、氨基酸和嘧啶代谢等功能。BC1826站位与其他站位相比,细菌多样性较低。结合沉积柱粒度分析结果,推测BC1826站位微生物群落结构的差异与沉积扰动有关,两者具有一定的响应关系。与已有研究成果汇总对比发现,西太平洋结核区与东太平洋结核区的细菌群落组成结构有较大差异。  相似文献   

贵州遵义县茶园锰铁矿地质特征及成因探讨     

高家育  孙传敏  刘严松  廖海 《四川地质学报》2011,31(2):204-208

贵州遵义县茶园锰铁矿属"遵义式锰矿"成矿带,具有一定的开发前景。该矿床赋存于二叠系上统龙谭组(P2l)底部,含矿岩层以粘土岩层为主,并含有大量的黄铁矿。通过对该矿矿床地质特征的野外调查,矿石矿物鉴定及元素分析,认为该矿床锰铁矿石为原生碳酸锰铁矿物,属于古风化壳沉积型矿床,锰质来源于晚二叠世湖盆周边玄武岩的古风化壳残留锰质,形成于弱碱性还原环境。  相似文献   

Fine-scale chemostratigraphy of cross-sectioned hydrogenous ferromanganese nodules from the western North Pacific     

Shiki Machida  Kentaro Nakamura  Tetsu Kogiso  Ryo Shimomura  Koichi Horinouchi  Kyoko Okino  Yasuhiro Kato 《Island Arc》2021,30(1):e12395

A broad area densely covered by ferromanganese nodules was recently discovered around Minamitorishima (Marcus) Island, representing a high-potential metal resource, particularly for Co, Ni, Mo, and W. We studied 16 nodule samples from nodule fields around Minamitorishima Island. To define the fine-scale chemostratigraphy of the nodules, polished cross-sections of the samples were analyzed by microfocus X-ray fluorescence. Our results show that a general pattern of compositional variation was common throughout the growth history of the nodules in all the regions we studied. Chemical mapping clarified changes in the chemical signature and proportion of five lithological components throughout the growth history: Mn represented columnar δ-MnO₂; Fe represented layered amorphous FeOOH*xH₂O; Ti represented TiO₂*2H₂O intergrown with an amorphous FeOOH phase; P, Ca and Y represented particles of biogenic calcium phosphate; and Si, Al, K, Cu, and Ni represented pelagic sediment infills. We proposed a method for a creating a multi-dimensional compositional map of the fine-scale chemostratigraphy observed in the ferromanganese oxide layers on the basis of merging the mapped Mn, Fe, Ti, P, Si and Cu intensities. Multi-dimensional compositional mapping of the sampled nodules from the western North Pacific revealed two fundamental findings: (1) previously recognized first-order Fe–Mn layers, L0, L1, and L2, were further divided into two, three, and four sublayers, respectively, and (2) a delayed supply of material to be nuclei of nodule or a growth hiatus of Fe–Mn layer(s), leading to missing sublayers in the layers L0 and L2, regulated the nodule size. In contrast, layer L1, which does not have any missing sublayers, was commonly observed in the samples for this study and has been reported in studies of other regions in the western Pacific. We propose, therefore, that the layer L1 is a key facies for examining chemostratigraphic correlations with other areas of seafloor.  相似文献   

黄土碳酸盐的研究   总被引：2，自引：0，他引：2       下载免费PDF全文

陈忠  马海州  曹广超  周笃珺  张西营  谭红兵  姚远 《盐湖研究》2006,14(4):66-72

黄土是过去气候变化研究的重要对象之一。黄土中的碳酸盐则是黄土研究的一个重要内容。黄土碳酸盐的研究涉及了对次生碳酸盐的辨识、碳酸盐的含量、碳酸盐中的碳氧同位素以及碳酸盐的Sr同位素及其它微量元素等内容。对前人在这几个方面的研究作一初步的归纳总结,包括次生碳酸盐的辨识和提取对解释古气候环境有重要意义;碳酸盐的含量可反映出黄土和古土壤之间的不同气候状况;根据碳酸盐中的碳氧同位素则能大体定量得到古温度以及古植被状况进而反映古降水情况;而Sr同位素及其它微量元素则能反映出当时的化学风化程度,指示季风的强弱变化。  相似文献   

海洋沉积物不同相态中Sr、Nd同位素提取方法研究   总被引：1，自引：1，他引：0  

张颖  张辉  王小静  刘季花  汪虹敏  朱爱美  胡宁静 《海洋学报》2020,42(2):155-166

海洋沉积物中Fe-Mn氧化物相和残渣态的Sr、Nd同位素组成能够敏感地指示洋流循环及物质来源,但实验室对沉积物中上述相态的Sr和Nd同位素的提取易产生过量或提取不完全,进而影响同位素测定结果的准确性,因此制定有效的提取流程显得非常重要。本文采用不同浓度盐酸羟胺(Hydroxylamine Hydrochloride,HH)与醋酸(Acetic Acid,HAc)混合溶液对中印度洋海盆深海沸石黏土、北极半深海沉积物以及安达曼海近海沉积物的Fe-Mn氧化物相进行提取,残渣态用HNO3-HF高压密闭消解法溶融,测定了各相态的主微量元素含量及Sr、Nd同位素组成,通过分析不同实验条件下得到的Fe-Mn氧化物相与残渣态的稀土元素(REE)配分模式、Al/Nd含量比值及Sr、Nd同位素组成,建立了3种不同成因类型海洋沉积物不同相态的化学提取方法。提取深海沸石黏土中Fe-Mn氧化物相的理想试剂条件为0.25 mol/L HH和15%HAc,北极半深海沉积物和安达曼海近海沉积物的试剂条件为0.5 mol/L HH和15%HAc。该方法可以准确获得沉积物中Fe-Mn氧化物相与残渣态的Sr、Nd同位素组成信息,为古海洋学的研究提供方法支持。  相似文献   

戈壁覆盖区金窝子矿带深穿透地球化学方法研究   总被引：7，自引：0，他引：7  

叶荣  王学求  赵伦山  陈德兴  傅渊慧 《地质与勘探》2004,40(6):65-70

文章以金窝子金矿带为例,讨论戈壁覆盖层的分带结构,以及金等成矿元素在干旱景观区的表生迁移和矿化信息的传递机制;试验研究了本区土壤和活动态测量等深穿透方法效果,提出了戈壁覆盖区化探勘查和找隐伏矿的技术方法.通过重点剖面和1200 km2面积1:20万比例尺的多指标地球化学测量证明,戈壁覆盖层主要由坡-冲积层和冲-洪积层互层构成,其中坡-冲积层属当地风化产物,包含矿化信息;而冲-洪积层为运积物.土壤(-160目)测量对于圈定区域金成矿构造带和显示出露矿化效果良好,应用水提取态和铁锰氧化物态等深穿透指标,可以揭示覆盖金矿化.  相似文献   

Quantitative estimation of seafloor features from photographs and their application to nodule mining     

Rahul Sharma 《Marine Georesources & Geotechnology》2013,31(4):311-331

Methods developed for quantitative estimation of seafloor features from seabed photographs and their application for estimation of nodule sizes, coverage, abundance, burial, sediment thickness, extent of rock exposure, density of benthic organisms, and their lebensspuren have been presented. Digitization of the photographs shows variable nodule size (< 1 to 10 cm), coverage (< 1 to 75%) and abundance (< 1 to 20 kg/m²). Nodule population is inversely proportional to the coverage of the sediment (10–100%) and its thickness (0 to > 10 cm), which causes differential burial (0–100%) of nodules. Correlation between nodule parameters (diameter and coverage) in the photographs and grab recovery is used to evolve empirical relationships for estimating nodule abundance in different seabed settings. The rock outcrops (basalts) with a coverage of 6–100% are the sources of nuclei for the nodules, the distribution of which is controlled by the local topography. Higher concentrations of nodules are observed along the slopes, followed by the crests of seamounts, and are lowest in the valleys and plains. A population density of 6–7 benthic organisms per 100 m² belonging to 7 different phyla is observed, with a high frequency of lebensspuren (4–12 traces/m²) in association with nodules. Estimation of these parameters can be used as important inputs in the design of the nodule collector, as it will have to encounter a variety of seafloor conditions, such as patchy nodule distribution, rock outcrops, steep slopes, and frequent microtopographic changes, as well as benthic life. The distribution and relation of various features with one another can also be used to understand the possible impact of nodule mining on the seabed. Estimates show that for a yield of 3 million tonnes of nodules per year, the volume of sediment disturbed will be between 200 × 10⁷ and 500 × 10⁷ m³over an area of 300–600 km², depending upon the average abundance of nodules. Hence, the nodule collector will have to be a self‐propelled system, with photographic and acoustic sensors, to enable selective mining and avoid unfavorable areas.  相似文献   

基于LA-ICP-MS多元素成像技术的早寒武世磷结核成因研究   总被引：3，自引：3，他引：0  

周文喜  王华建  付勇  叶云涛  王晓梅  苏劲  王富良  葛枝华  梁厚鹏  魏帅超 《岩矿测试》2017,36(2):97-106

我国下寒武统底部广泛发育磷结核、磷块岩等富磷沉积,为早寒武世最为重要的化学标志层之一,也代表了隐生宙—显生宙转折期地球表层系统的重大变革。当前对磷来源和富集机制的解释不一。为进一步明确该时期富磷沉积的形成机制,本文利用激光剥蚀电感耦合等离子体质谱联用技术(LA-ICP-MS)对贵州金沙地区牛蹄塘组黑色页岩中的磷结核进行多元素原位微区成像研究。结果表明:磷结核中各元素富集情况清晰地记录了磷结核形成过程中微环境的变化趋势。其中,磷结核内部Ca、P共富集以及Si亏损,指示P富集缘于自生磷灰石生成,P则来自于有机质含氧或厌氧降解释放;Mn、Zn与P共富集于磷结核内部,指示结核形成时的底部水体为含氧水体;As、Mo、V等元素主要富集于围岩或黑色页岩,指示缺氧含H_2S水体形成终止了结核生长。本研究显示,LA-ICP-MS原位多元素成像技术能够获取微区内丰富的地球化学信息,并提供高精度可视化证据,未来将在地质勘探和古环境研究等领域得到更广泛应用。  相似文献   

大洋多金属结核矿区表层沉积物的物理性质     

陈小玲 《海洋学研究》2004,22(1):28-33

利用大洋多金属结核矿区调查过程中4个航次所得的600多组表层沉积物物性测试资料,将矿区的沉积物分为5种类型,并分析了这些沉积物的物理性质,同时,运用回归分析方法,统计分析了不同类型沉积物的含水量、湿密度、孔隙比与埋藏深度的关系,以及各物性指标之间的相关关系。结果表明:(1)大洋多金属结核矿区表层沉积物均为粉质土,黄棕色粉质土是西部矿区的主要沉积物类型,棕黄色粉质土是东部矿区的主要沉积物类型;(2)除褐色粉质土外,其余4种类型土的含水量、孔隙比均随埋藏深度的增加而减少和降低,湿密度则随深度增加而增大;(3)各类土的物性指标与埋藏深度的相关性甚好,因而可以利用埋藏深度对矿区的沉积物进行物性指标预测;(4)含水量、孔隙比、湿密度等物性指标之间呈线性相关,其中含水量与孔隙比的相关性最为密切,呈明显线性关系。  相似文献   

铁锰氧化物/硅藻土复合物的制备及其对磷的吸附性能研究     

郝艳玲  常庆露  屈奥运 《岩石矿物学杂志》2019,38(2):273-278

采用氧化还原共沉淀法制备铁锰氧化物/硅藻土复合物,考察原料配比、反应温度、焙烧温度及溶液pH值、离子强度对该复合物吸附磷性能的影响,同时开展吸附等温线、XRD和IR等分析。结果表明,2. 5 g硅藻土与1. 0 mmol锰、3. 0 mmol二价铁、3. 0 mmol三价铁制备的复合物在20℃、pH值为6时对磷的吸附量为10. 84 mg/g,较硅藻土提高约3. 6倍;沉淀反应温度对复合物吸附性能影响很小,焙烧温度400～500℃有利于复合物对磷的吸附;吸附量随溶液pH值的增大而减小,pH值较低时吸附作用主要是静电吸引和内层络合,pH值较高时减弱的静电吸引和内层络合与有利于吸附的内层络合共吸附综合作用,表现为吸附量减小;吸附等温线符合Langmuir方程,饱和吸附量34～37 mg/g,与D-R方程、R-P方程有较好相关性,平均吸附能9. 9～11. 3 kJ/mol,复合物具有微孔结构,有单层也有多层吸附。  相似文献