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为探讨富钴结壳中元素的成因,采用了化学容量法、原子吸收、X-射线衍射分析、电子探针、等离子光谱等技术,对太平洋麦哲伦海山区MA海山、MC海山上的富钴结壳分老世代和年青世代层进行了矿物成分与元素成分分析。据分析结果,区内主要赋存水成富钴结壳,富钴结壳中的矿物组分以锰相矿物的水羟锰矿为主,其次为铁相矿物(针铁矿等),还有磷灰石和少量次要矿物(钙十字石、石英等)。老世代富钴结壳,磷酸盐化明显,个别层内CaCO_3高达29%,P_2O_5高达8%。新老壳层间在元素含量上有差异,特别是Fe、Mn、Co和Y等元素含量有明显的差异。据因子分析结果,老世代壳层中的元素有6个成因组合:(1)水成元素(Mn、Co、Fe);(2)稀土元素(Ce除外);(3)磷灰石组分(CaCO_3、P_2O_5);(4)生物成因元素(Zn、Cu);(5)热液成因元素(Pb);(6)碎屑成因组分(MgO)。新世代壳层中,有4个元素成因组合:(1)水成元素(Mn、Co、Ni);(2)稀土元素(Ce除外);(3)磷灰石组分(CaCO_3、P_2O_5);(4)生物成因元素(Zn、Cu)。根据元素相关矩阵分析及主元素对应分析结果,结合富钴结壳的宏观与显微结构构造特征,认为老世代壳层成矿的主要海洋学因素是因南极冰盖扩大和南极底流与大洋环流作用增强,在海山斜坡形成的氧化作用环境、以及赤道太平洋表层海水高生物生产力引起的最低含氧层扩大作用。这两种作用,造成了老世代富钴结壳层磷酸盐的富集及其与含Fe、Mn矿相形成有时空上的分异。新世代富钴结壳层成矿的主要海洋学因素是南极冰盖发育与大洋环流引起的海底氧化作用。
In order to explore the origin of the elements in the cobalt-rich crust, the cobalt-rich junction of MA seamounts and MC seamounts in the Magellan seamounts in the Pacific Ocean was studied by chemical capacity method, atomic absorption spectroscopy, X-ray diffraction analysis, electron probe and plasma spectroscopy. The mineral composition and the elemental composition of the crust were divided into the old generation and the young generation. According to the analysis results, the main water-rich cobalt-rich crusts in the region, the mineral components in cobalt-rich crusts are mainly manganese hydrometals, followed by iron-bearing minerals (goethite, etc.) and phosphorus Gray stone and a small amount of secondary minerals (calcium stone, quartz, etc.). The older generation of cobalt-rich crusts with obvious phosphatization showed CaCO_3 in individual layers up to 29% and P_2O_5 up to 8%. There is a difference in element content between the new shell and the old one, especially the contents of Fe, Mn, Co and Y are obviously different. According to the result of factor analysis, there are 6 genetic elements in the Oligocene shell: (1) water-forming elements (Mn, Co, Fe); (2) rare earth elements (CaCO_3, P_2O_5); (4) biogenic elements (Zn, Cu); (5) hydrothermal genetic elements (Pb); There are four elements in the Cenozoic crust: (1) water-forming elements (Mn, Co, Ni); (2) rare earth elements other than Ce; (3) apatite components (CaCO 3, P 2 O 5) ; (4) biological genetic elements (Zn, Cu). According to the analysis of elemental correlation matrix and the corresponding analysis of major elements, combined with the macroscopic and microstructural features of the cobalt-rich crust, it is considered that the major oceanographic factors of the ore-forming of the old-age crust are due to the expansion of the Antarctic ice sheet and the convergence of the Antarctic underflow and the oceanic circulation The role of oxidation, the formation of the seamount slope oxidation environment, and the Equatorial Pacific Ocean surface water biological productivity caused by the lowest oxygen layer expansion. These two kinds of actions have resulted in the enrichment of phosphates in the cobalt-rich crust of the old generation and their spatial and temporal differentiation with Fe and Mn ore-bearing phases. The main oceanographic factors of the new generation cobalt-rich crust mineralization are the seafloor oxidation caused by the development of the Antarctic ice sheet and the oceanic circulation.