- 责任者：Chang Huajin (School of Life and Geography Sciences ; Qinghai Normal University ; Xining 810008 ; China) ; Chu Xuelei
- 刊名：Advances in Earth Science
- 出版年：2011
- 卷期：26(5)
- 关键词：黄铁矿 ; pyrite ; 古海洋学 ; paleooceanography ; Eh ; Eh
- 页码：p.475-481
- 图表：4 illus., 1 table, 47 refs.
- 分类号：0700
- issnNo：ISSN1001-8166
- isbnNo：CN62-1091/P
Framboidal pyrites are densely-packed, raspberry-like, spherical aggregates of equigranular, micron-sized crystals or microcrysts. Because of the difference principle in framboidal pyrites formation between oxic and euxinic depositional conditions, size distribution of framboids is indicative of oxygen levels for palaeo-ocean water column. However, only oxic and euxinic conditions can be definitely distinguished but suboxic or ferruginous conditions (anoxic and containing dissolved Fe2+) using the framboidal pyrites, and framboids formed in ferruginous condition may indicate euxinic environment. Therefore, incompatible results for deep-water redox conditions of the terminal Ediacaran Nanhua Basin have been achieved using framboidal pyrites size statistics and other available methods, respectively. The authors consider that the euxinic deep-water condition implied by framboids was incorrect, and the small pyrites may be formed due to limited sulfate concentrations in the basin and accordingly little H2S supply. In order to get credible results, other proxies, such as iron species, redox sensitive trace elements and stable isotope methods should be applied simultaneously when using framboidal pyrites to reconstruct palaeo-ocean environments.