摘要
根据连续沥取实验结果及相关文献,富钴结壳的生长可用一个双阶段胶体-化学吸附模型来说明.第一阶段是混合胶体的形成及元素的清除与富集,富氧的底层水与缺氧、富Mn2+的中层水体混合,Mn2+被氧化而形成MnO2胶体,并与水柱中的Fe(OH)3、Al(OH)3、SiO2、Ti(OH)4等胶体形成多种混合胶体[MnO2-Fe(OH)3、Fe(OH)3-Ti(OH)4和Fe(OH)3-Al(OH)3-SiO2],后者根据各自的表面物理化学特征吸附和富集不同的元素;第二阶段是混合胶体的沉积及富钴结壳的生长,第一阶段形成的混合胶体在海山基岩上以氧化物或氢氧化物的形式沉积,吸附的元素结合进矿物点阵,然后通过自催化或自反馈的方式生长.在富钴结壳生长中,生物起着重要的作用,包括为富钴结壳的生长提供大量的成矿物质、对Mn2+的催化氧化作用及在铁锰胶体的沉淀及富钴结壳壳层的生长过程中的媒介作用.
Based on the results of the sequential leaching of two Co-rich crusts from the western and central Pacific Ocean and related literature,a double stage colloid-chemical model was adopted to demonstrate the growth of Co-rich crusts.In the first stage,Mn2＋ is oxidized and forms MnO2 colloids after the Mn2＋-rich and anoxic intermediate water mixes with oxygen-rich deep water.The MnO2 colloid together with other colloids in seawater produce mixed colloids such as MnO2-Fe（OH）3,Fe（OH）3-Ti（OH）4 and Fe（OH）3-Al（OH）3-SiO2.These mixed colloids sca-venge elements from ambient seawater consistent with their surface physiochemical characteristics.In the second stage,these mixed colloids precipitate on the substrate rocks of seamounts as oxides or hydroxides and incorporate the adsorbed elements into the mineral phases before the crust grows autocatalytically or via auto-feedbacks.Furthermore,biological activity may play an important role in the growth of Co-rich crusts as follows：（1） the dissolution of calcareous plankton skeletons may provide abundant mineral materials for the growth of Co-rich crusts;（2） microbial activity may accelerate the oxidation of Mn2＋ and（3） act as a catalyst during the precipitation of ferromanganese colloids and the growth of Co-rich crust lamellas.
出处
《台湾海峡》
CAS
CSCD
北大核心
2011年第1期1-9,共9页
Journal of Oceanography In Taiwan Strait
基金
中国大洋协会国际海底区域研究开发"十一五"项目(DY115-01-2-5)
关键词
海洋化学
富钴结壳
成因
胶体化学吸附模型
生物作用
marine chemistry
Co-rich crusts
genesis
colloid-chemical model
biological activity
