控制铁锰结核地球化学特征的主导因素研究——Ⅰ.铁锰结核的地球化学特征

本文通过对南海和太平洋中北部57个站位不同类型结核中某些常量、微量、稀土元素和结核的红外光谱、X衍谢、扫描电子显微镜、电子探针的资料分析,详细研究了铁锰结核的地球化学特征。结果表明,不同Mn/Fe的结核具有不同的地球化学特征。结核中Mn/Fe与结核的元素组分、矿物组成及结核的丰度、品位、生长速度及沉积环境密切有关。从而结核的Me/Fe可以作为划分铁锰结核类型的指标。     

铁、锰在早期成岩过程中分离及其生物地球化学机制

本文通过对长江口及邻近陆架区沉积物、间隙水、上覆水和生物(细菌)的资料研究。指出了铁、锰在早期成岩过程中分离及其规律,并从生物地球化学角度阐述了这种分离的机制。     

CONCENTRATION, SOURCE OF MANGANESE AND IRON IN FERROMANGANESE NODULES AND THE RELATIONSHIP BETWEEN NODULES AND SEDIMENTARY ENVIRONMENTS IN NORTH PACIFIC REGION

The concentration, source of manganese and iron in ferromanganese nodules and therelation between nodules and sedimentary environments are discussed in detail by asynthetical study on chemical information of ferromanganese nodules and correspondingsediment, pore water and geological, biological (bacteria) information in 26 stations fromthe North Pacific region (7- 13°N, 178- 165°W). The result shows that (i) the concen-tration and distribution characteristics of magnese and iron in ferromanganese nod-ules differ in different types of nodules, however, the concentration decreases with theincrease in grain sizes of nodules; (ii) the source of iron in different types of nodulesis basically the same, i. e. the slow sedimentation of overlying water; (iii) manganesein nodules comes mainly from the diffusion of Mn~(2+) in the pore water, and Mn~(2+) fromthe reduction of Mn~(4+) in sediments by the medium of bacteria. As the distribution of bac-teria is believed to be strongly affected by the sedimentary envi     

北太平洋铁锰结核中Fe,Mn的含量、来源及其与沉积环境的关系

通过对太平洋北部(7—13°N,178—165°W)6×10~5km~2海域26个站位65个结核样品的化学资料,结合结核相对应的沉积物、间隙水及地质、生物(细菌)资料对比研究表明:(1) 结核类型不同,结核中Fe,Mn的含量及分布规律明显不同,但都随着结核的粒径增加而减少;(2) 不同类型的结核,Fe的来源基本相同,主要来自上覆水的缓慢沉积;(3) 结核中Mn主要来自间隙水中Mn~(2+)的扩散。这种扩散的Mn~(2+),主要来自沉积物中Mn~(4+)的还原(在细菌媒介下)。因为细菌受环境制约,随着沉积环境不同而有差异,从而导致形成的结核类型不同。     

东海陆架区沉积物中铁、锰、硫化物、有机质和细菌间关系的探讨

本文从生物地球化学观点出发,详细讨论了东海陆架区沉积物和间隙水中铁、锰、硫化物、有机质和细菌间的关系。研究表明:在细菌媒介下,沉积物中铁、锰和水体中硫酸根都参与了沉积物中某些有机物的降解反应;弧菌(Vibrionaceae)和棒状形菌(Coryneforms)可能是水体中硫酸根参与降解有机物反应时的主要媒介物;弧菌和假单孢杆菌(Pseudomonas)可能是Fe~(3+)还原时的主要媒介物;而传代中死亡细菌和G~-杆菌则可能是Mn~(4+)还原时主要媒介物。笔者提出东海陆架区沉积物中硫酸根(SO_4~(2-))是降解有机物的主要电子接收者。     

MAIN FACTORS STUDY OF THE CONTROLLING GEOCHEMICAL CHARACTERISTICS OF FERROMANGANESE NODULES (Ⅰ)——GEOCHEMICAL CHARACTERISTICS OF FERROMANGANESE NODULES

The geochemical characteristics of ferromanganese nodules have been described in detail by the information study of major elements, trace elements, rare earth elements and infrared spectrophotometer, X-ray diffraction, electronic probing, electronic microscope analysis in 57 ferromanganese nodules of different types from the South China Sea and the Northern Central Pacific Basin. The result shows that (ⅰ) the different types of ferromanganese nodules have different geochemical characteristics; (ⅱ) there is a close relationship between Mn/Fe in ferromanganese nodules and their element content, mineral composition, nodule abundance, tenor (Cu+Co+Ni)%, growth Speed and sedimentary environment. It has suggested that Mn/Fe in nodules can be an indicator of classifying ferromanganese nodule types.     

SEPARATION OF IRON AND MANGANESE IN THE EARLY DIAGENETIC PROCESSES AND ITS MECHANISM OF BIOGEOCHEMISTRY

Study shows that the reduction of iron (Fe~(3+)) and manganese (Mn~(4+)) in modern sedi-ments and the diffusive flux of the Mn~(2+) from the pore water into the overlying waterare mainly controlled by bacteria, and the distribution of the bacteria is believed to beaffected strongly by the sedimentary environment. It is the diffusive fluxes between Fe~(2+)and Mn~(2+) that lead to the separation of iron and manganese in the modern sediment at theChangjiang Mouth and near the shore. The level of the separation decreases with theincrease of the overlying water salinity and increases from the surface to the depth. Thismechanism has given a new explanation why manganese is concentrated in sediments onthe oceanic floor of ferromanganese-rich nodules.     

控制铁锰结核地球化学特征的主导因素研究—Ⅱ.不同Mn/Fe结核的形成机制

本文在前文研究的基础上,通过对不同Mn/Fe结核与相对应的沉积物(岩石)、间隙水、上覆水、生物(细菌)资料对比研究,从稀土元素地球化学、沉积地球化学、生物地球化学角度,详细研究了不同Mn/Fe结核的形成机制。结果表明,不同Mn/Fe结核形成机制不同,按其成因可分三类。