| 摘要: |
| 自生黄铁矿是现代海洋沉积物中分布较广、含量较高的自生矿物之一。我国广阔的大陆架海域以及边缘海区(冲绳海槽)的现代和近代沉积物中都发现有黄铁矿,其中以南黄海盆地较为典型。H-106孔位于南黄海中部略偏西北(123°0'E,35°3'N),水深70m,岩芯长607cm,孔中黄铁矿含量较高。
研究现代和近代柱状沉积物中自生黄铁矿的结构、构造、矿物化学特征以及硫同位素组成及其与沉积环境和地球化学等因素的关系,对于了解沉积物早期成岩作用,认识沉积环境变迁和探讨黄铁矿成因都具有理论和实际意义,因此,早已引起国内、外学者的重视。国外具有代表性的学者Love(1957;1964)和 Berner(1969;1970)等分别从50年代和60年代末就开始了黄铁矿的研究工作。他们从不同角度、用不同方法对古地层和现代海洋沉积物中的黄铁矿进行了研究。随着我国海洋调査研究的深入,近年来国内学者也相继开展了这方面的工作(陈庆,1981;王琦等,1981)。然而以往国内、外的学者大都从形态、矿物和沉积化学的角度去研究黄铁矿,对现代自生黄铁矿单矿物的硫同位素组成涉及甚少。现代海洋硫同位素研究也仅限于沉积物与海水的范围,然而沉积物和海水的成分均很复杂,影响因素众多,不能反映黄铁矿的硫同位素组成。本文拟通过黄铁矿的硫同位素特征和黄铁矿集合体的结构、构造和矿物化学成分等矿物学特征,并结合沉积物成分与地球化学参数来探讨黄铁矿的形成环境与成因。 |
| 关键词: 自生黄铁矿、南黄海中部、柱状沉积物 |
| DOI： |
| 分类号: |
| 基金项目:中国科学院海洋研究所调查研究报告第2019号 |
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| STUDY ON THE AUTHIGENIC PYRITE IN THE CORE H-106 FROM THE CENTRAL SOUTH YELLOW SEA |
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Li Anchun, Chen Lirong, Shen Shunxi, Huang Qiuhuo
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Institute of Oceanology, Academia Sinica
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| Abstract: |
| The many biogenic and nonbiogenic pyrites in the 607cm long core H-106 taken from 70m water depth in the central South Yellow Sea were composed of numerous tiny framboids consisting of countless tiny octahedral crystals. Electron microprobe analysis showed the pyrites were mainly composed of sulfur (50.59% in average) and iron (47.94% in average). Lighter sulfur dominate the sulfur isotope composition of pyrite. The values of sulfur isotopes range from-39.5 to-28.9 per mil (average of-36.0 per mil). The sulfur isotope fractionation coefficient between pyrite and sulfate in seawater is from 1.0510 to 1.0626. There was little variation of sulfur isotopic composition with core depth. The research showed pyrite formed in the sediments slowly deposited in the study area where average bottom water temperature in 24 years is 8.06℃ and average concentration of organic matter and iron in the sediments are 2.14% and 4.6%, respectively. Sulfur isotopic composition and other evidence showed the. pyrite here was formed slowly(about 10 years). |
| Key words: South Yellow Sea,authigenic pyrites |
