摘要
新元古代南沱冰期海洋磷浓度出现了大幅度升高,但升高的原因研究甚少。本文尝试通过新元古代南沱冰期铁结合态磷占总磷比例的分析,结合游离态氧化铁与全铁的比值来探讨磷在南沱冰期海水中的迁移转化规律。分析结果显示,样品中绝大多数游离态氧化铁与全铁的比值均大于0.38,且南沱组岩石中所含黄铁矿的含量极少,表明南沱冰期海水呈缺氧含铁的状态,反映当时大气氧浓度较低。样品中铁结合态磷占总磷比例的平均值为75.54%,推测经冰下风化作用后的磷主要是以溶解态被冰下流水带入海洋,较低的大气氧浓度和缺氧的海水是南沱冰期海洋磷富集的主要原因。
Neoproterozoic Nantuo Ice Age witnessed high marine phosphorus concentration, but the origin keeps unknown. Here, we analyses iron and phosphorus concentrations both in bulk samples and bound by iron oxides in order to explore the mobility and transport of marine phosphorus during Nantuo Ice Age. The analytic result shows that Fed/TFe of the most diamictite are higher than 0.38, and the pyrite content in the samples is less than 1%, so the marine was dominated by ferruginous condition and a limited atmospheric oxygen concentration during Nantuo Ice Age. Meanwhile, these data deduce the concentration of atmospheric oxygen is low. The average of Fe -P/TP in the samples is 75.54%. It is suggested that most continental phosphorus released by the subglacial weathering was transported into the sea under the low atmospheric oxygen concentration. With the help of domina- ted ferruginous condition the phosphorus was accumulated during the Nantuo Ice Age.
出处
《贵州大学学报（自然科学版）》
2016年第2期51-56,共6页
Journal of Guizhou University:Natural Sciences
基金
国家自然科学基金项目(编号41162003)
关键词
南沱冰期
磷
地球化学
缺氧含铁环境
Nantuo Ice Age
phosphorus
geochemistry
ferruginous condition
作者简介
毕晨时（1988-），女，在读硕士，研究方向：岩石地球化学，Email：1988bes@163．com．
通讯作者：顾尚义．Email：gushangyi@126．com．
