【摘要】 笔者首次对太平洋与大洋富钴结壳密切相关的海山磷酸盐的成因及形成环境进行了比较深入的研究。研究发现 ,各种产出形态的磷酸盐都不同程度地交代碳酸盐等含钙物质 ,而呈现出交代生物结构、交代凝灰结构、交代角砾状结构及交代填间结构等各种交代结构 ,反映了磷酸盐的交代成因。此外 ,其δ13 C值 (变化于 0 .7‰～ 2 .0‰之间 )也证实其属于交代成因。磷酸盐中Na、Mg、Sr、F、P2 O5含量以及Na/P2 O5、Mg/P2 O5、Sr/P2 O5、F/P2 O5的比值 ,特别是晶格中结构CO2 的含量 (变化于 5 .7%～ 6 .2 %之间 ) ,与形成于氧化环境下的Blakeplateau、ChathamRise、AgulhasBank等处的磷酸盐相近 ,表明调查区磷酸盐亦形成于氧化环境。氧同位素测定结果表明 ,磷酸盐的形成温度为 5 .8～ 14 .8℃ ,平均为 11.5℃ ,显示其形成于正常的海水温度环境。西、中太平洋海山磷酸盐形成环境十分接近的事实暗示 ,西、中太平洋广大区域内的成磷事件存在着时间上和成因上的统一性和相似性。更多还原

【Abstract】 The origin and formation environment of phosphates associated closely with cobalt-rich crusts dredged from Western and Central Pacific submarine guyots have been investigated. Studies of 13 phosphate samples show that carbonates and other calcium-bearing materials have been replaced by phosphates in various degrees. Various textures such as replacement relict, replacement biological texture, replacement tuff, replacement breccia and replacement intergranular texture were found.δ 13 C values vary in the range of 0.7‰～2.0‰. Both the characteristics of various textures and the δ 13 C isotopic composition demonstrate that the phosphates are of replacement origin.The contents of Na, Mg, Sr, F, P 2O 5 and the ratios of Na/P 2O 5,Mg/P 2O 5,Sr/P 2O 5 and F/P 2O 5 in phosphates from the study area, especially the contents of structural CO 2 (ranging from 5.7% to 6.2%), are similar to those of phosphates from Blake plateau, Chatham Rise and Agulhas Bank formed under an oxidation environment, indicating that the phosphates studied were also formed under an oxidation environment. The formation temperature of the phosphates in the study area varies from 5.8 to 14.8 ℃ with an average value of 11.5 ℃.It can be deduced that they were formed in an environment of normal sea water temperature. The similarity between the phosphates from Western Pacific and those from Central Pacific in the origin and formation temperature suggests that there exists a uniformity between the phosphatization events in this area both in time and in origin.更多还原