【摘要】 通过对长江口及邻近陆架区现代沉积物中自生硫化铁、细菌、沉积物和间隙水化学成份研究表明,研究区自生黄铁矿主要受硫酸盐还原和元素硫供给速度的控制。 利用²¹⁰Pb的资料证实,研究区自生黄铁矿形成约需10年左右时间。作者提出,在基本相同的沉积环境中,利用自生硫化铁中FeS₂/FeS克分子比值最高值在沉积柱上所对应的沉积物厚度,除以自生黄铁矿在该环境中形成所需的时间,就可得出不同站位上的沉积速率,其结果和²¹⁰Pb、生物及地质学上描述的沉积速率基本一致。更多还原

【Abstract】 Iron sulfide is an authigenic mineral widely distributed in the modern marine sediments.Analysis of iron sulfide, bacteria and the chemical conditions of the interstitial water and sediments in the top 0 - 10 em sediment cores from the Changjiang River mouth and near-shore showed that the formation rate of the authigenic pyrite in the stiidy area depends mainly on the sulfate reduction and supply of the element sulfur in the sediments.Supply and reduction of the element sulfur in the marine sediments are related to the following factors: 1) the availability of dissolved sulfate in the overlying water, 2) the pH, Eh and the amount of the organic matter available for bacterical decomposition, and 3) the kinds of bacteria in sedimentary environment. Therefore, when the environmental conditions are similar to those mentioned above, the forming rate of the authigenic pyrite would be similar too. The molar ratio of FeS2/FeS in the authigenic iron sulfide can reflect the degree of alteration from the single iron sulfide (FeS) to the authigenic pyrite. That the highest molar ratio of FeS2/FeS occurred on the sediment column showed that the authigenic pyrite was formed in this sedimentary environment, which took about ten years as proved by 210Pb. The sedimentary rate can be expressed aswhere R is the sedimentation rate (cm/a), 8 is the sediment thickness (cm) corresponding with the highest molar ratio of FeS2/FeS occurred in the sediment column, T is the time of forming the authigenic pyrite.The results obtained from the formula correspond with that obtained from 210Pb, biology and geology.更多还原