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研究了采自东太平洋海隆13°N(EPR 13°N)的一个热液成因含金属箱式沉积物岩心E272的孔隙率变化特征。样品孔隙率在70.0%-85.2%之间,顶部层位比底部层位高14%左右。孔隙率随深度增加而指数式单调递减,平均递减梯度约为-0.31%/cm。该岩心上部层位呈红棕色,下部层位呈黄绿色,表明该岩心经历了显著的早期化学成岩作用。前人关于该岩心的元素地球化学,粒度和年代学数据,共同证明该岩心孔隙率随深度变化特征受稳态压缩过程控制。其孔隙率随深度的变化关系符合稳态压缩模型的经验拟合公式。E272顶部沉积物-水界面处溶解物质与海水的交换以离子扩散机制为主,而岩芯内部溶解物质的迁移则可能主要受自下而上的孔隙水流动机制控制,这与岩芯中活动元素含量上部高,下部低的分布模式一致。该研究对将来进一步讨论E272岩心在早期成岩作用中的化学过程具有指导意义。
The porosities of E272, a hydrothermal-bearing metallogenic sediment core collected from the East Pacific Rise at 13 ° N (EPR 13 ° N), were studied. The porosity of the sample is between 70.0% and 85.2%, and the top layer is about 14% higher than the bottom layer. Porosity decreases exponentially with increasing depth, with an average decreasing gradient of -0.31% / cm. The upper core of the core was reddish brown in color and the lower interlayer was yellow-green, indicating that the core experienced significant early chemical diagenesis. The previous data on elemental geochemistry, grain size and geochronology of the core show that the core porosity is controlled by the steady-state compression process with the depth variation. The relationship between porosity and depth changes accords with the empirical fitting formula of steady-state compression model. E272 The sediment-water interface at the top of sediment-water interface is dominated by the ion-diffusion mechanism and the migration of dissolved matter inside the core may be mainly controlled by the pore-water flow mechanism from bottom to top, Elemental content of the upper high, the lower distribution pattern of the same low. The study is of guiding significance to further discuss the chemical process of E272 core in early diagenesis.