古海洋生产力与氧化还原指标——元素地球化学综述

海洋表层初级生产力大小以及水体氧化还原条件是古海洋和古气候研究的重要内容,而元素地球化学是研究初级生产力以及氧化还原条件最常用的手段。主量元素Fe和Si是限制生物的营养元素,痕量金属元素Cu、Ni和Zn是微营养元素,而营养条件是沉积生产力的限制因素,因此这些元素的含量能反映初级生产力大小。Ba和Mo是随有机质一起沉淀下来的,与水体的有机碳通量有关,也是古生产力大小的指标。对氧化还原敏感的痕量金属元素含量（如Cr、V和U）以及元素比值（如V/（V＋Ni）、V/Cr、Ni/Co、U/Th和V/Sc）常用来重构水体的氧化还原条件。

Productivity and redox proxies of palaeo-oceans: An overview of elementary geochemistry

It is important for the study of palaeo-oceanography and palaeoclimatology to estimate the primary productivity in surface water and redox conditions in water columns.The study of primary productivity and redox conditions is usually carried out with the aid of elementary geochemistry.Since the availability of nutrients is the main limiting factor to planktonic productivity,the contents of bio-limiting nutrient elements(such as Fe and Si)and micro-nutrient elements(such as Cu,Ni and Zn)reflect the level of primary productivity.Ba and Mo which accumulate with the falling of organic matter setting are related to the organic-carbon flux.Therefore,Ba and Mo can also be used as primary productivity proxies.As for the redox-sensitive trace metal elements(such as Cr,V and U),their contents and elementary radios(such as V/(V+Ni),V/Cr,U/Th and V/Sc)can be usually used to reconstruct the redox conditions in water columns.