摘要
中国首次对与大洋富钴结壳密切相关的磷酸盐化作用进行了研究。对取自西太平洋麦哲伦海山区一厚度为 10cm的富钴结壳样品 ,自顶至底以 5mm间距采取了 2 0个分层样品进行了成矿元素和稀土元素分析。结果表明 ,未被磷酸盐化的新结壳和磷酸盐化的老结壳间主要成矿元素的含量相差显著。老结壳中Fe、Mn、Si、Al、Zn、Mg、Co、Ni、Cu元素亏损 ,亏损次序为Co >Ni>Mg >Al>Mn >Si>Cu >Zn >Fe;而Ca、P、Sr、Ba、Pb元素含量增加 ,富集次序为P >Ca >Ba >Pb >Sr。研究认为 ,结壳中磷酸盐化作用的强弱制约着富钴结壳成矿元素含量的变化 ,磷酸盐化作用是造成老结壳中主要成矿元素Co、Ni等贫化流失的根本原因。研究还表明 ,磷酸盐化作用对富钴结壳的稀土元素丰度也产生一定影响 ,使老结壳的稀土总量和Ce含量高于新结壳 ,但未显著改变其稀土配分模式和分馏特征。研究证实 ,老结壳的Y正异常与磷酸盐化作用无关。
The phospharization related closely to marine cobalt rich crusts has been studied in detail. Sampling from top to bottom of a 10 cm thick sample dredged from Magellan seamount, NW Pacific, was conducted at an interval of 5 mm. The concentrations of ore forming and rare earth elements in 20 subsamples were determined. The results show that an obvious difference exists between the new unphospharized crusts and the old phospharized crusts. Fe, Mn, Si, Al, Zn, Mg, Co, Ni, Cu are depleted while Ca, P, Sr, Ba, Pb are enriched in old crusts. The order of depletion and enrichment is Co>Ni>Mg>Al>Mn>Si>Cu>Zn>Fe and P>Ca>Ba>Pb>Sr respectively. It can be concluded that the intensity of phospharization controls the concentration variation of ore forming elements in crusts and causes the loss of Co, Ni and other main ore forming elements.The phospharization also affects the abundance of REE in crusts. The abundance of REE and the content of Ce in old crusts are higher than those in younger crusts. The patterns and fractional distillation characteristics of REE in new and old crusts have not changed fundamentally. Y positive anomaly in old crusts has no relation with the phospharization. The research on phospharization of crusts supplies useful information for the evaluation and comprehensive utilization of crust mineral resources.
出处
《地球学报》
EI
CAS
CSCD
北大核心
2002年第5期403-407,共5页
Acta Geoscientica Sinica
基金
中国大洋矿产资源研究和开发协会 (COMRA)资助的富钴结壳研究项目
"大洋富钴结壳形成富集的地球化学限制"(DY95 0 8 0 5 )的研究成果之一
