中太平洋阿利森海山富Co结壳成矿元素的富集机制  

ENRICHING MECHANISM OF MINERALIZING ELEMENTS IN CO-RICH CRUST ON ALLISON SEAMOUNT,CENTRAL PACIFIC OCEAN

作　　者：张俊[1] 孟宪伟[1] 王湘芹[1] 

机构地区：[1]国家海洋局第一海洋研究所,海洋沉积与环境地质国家海洋局重点实验室,青岛266061

出　　处：《海洋地质与第四纪地质》2014年第4期59-63,共5页Marine Geology & Quaternary Geology

基　　金：中国大洋协会"十五"资助项目(DY105-01-01-09);"973"规划项目-典型户后盆地热液活动及其成矿机理(2013CB429700)

摘　　要：以中太平洋阿利森海山的Al-l富Co结壳为研究对象,在其结构观察、年龄标定和生长世代确定的基础上,平均按1.3mm间隔取样,测定各分层常微量元素含量,计算了结壳中各元素的富集系数和分布系数。结合元素富集系数、分布系数和特征元素对比值,探讨了古环境演化对结壳中元素富集的制约。研究表明,结壳中富集的元素正是那些在海水中滞留时间较短的元素;结壳是海洋中"清扫"型元素重要的"汇";元素在海水的行为是其在结壳中富集的内因。碳酸盐的溶解导致的Fe、Ba的释放有利于结壳的生长,但却"稀释"了Mn、Co、Ni等元素的累积;最低含氧带的发育和南极底层水活动的加强利于Mn、Co等元素的氧化和"清扫"。结壳的生长间断是南极底层流活动减弱和活动模式发生根本转变的结果;火山活动沉积抑制了结壳的生长;6.8Ma是结壳从快速生长到缓慢生长发生转变的关键时期。Based on its structure,growth age and growth generations,the crust A1-1from the Allison seamount of the Central Pacific Ocean was sub-sampled at an average interval of 1.3mm in order to measure the concentrations of major and trace elements for each layers and subsequently to calculate the enrichment coefficient and distribution coefficient of the mineralizing elements of the crust.According to the coefficients and special element ratios,the constraint of paleo-environment on the enrichment of mineralizing elements in the crust was discussed.The study shows that the elements enriched in the crust are just those that have shorter resistant time in seawater.The crust is an important＂sink＂for the elements that are easily scavenged.The element behaviors in seawater are the intrinsic causation for their enrichment in crust.The release of iron and barium resulted from the dissolution of carbonate is favorable for crust growth,but dilutes the accumulation of manganese,cobalt and nickel.The development of Minimum Oxygen Zone and the strengthening of Antarctic Bottom Water are favorable for the oxidation and scavenging of manganese and cobalt.The growth hiatus occurring in crust is resulted from weakening and ultimate change of Antarctic Bottom Water.Volcanic ash restrains crust growth.It was at 6.8 Ma when the crust grew from rqpid to slow rake.

关 键 词：中太平洋海山 富钻结壳 富集系数 分布系数 富集机制 

分 类 号：P736.4[天文地球—海洋地质]