西南印度洋49°～56°E洋脊段的热液羽状流:来自深水中的氦同位素异常证据  

The hydrothermal plumes over the Southwest Indian Ridge from 49°E to 56°E: Evidence from helium isotope anomalies of deep seawater

作　　者：卢映钰 韩喜球[1] 王叶剑[1] 邱中炎[1] 

机构地区：[1]国家海洋局第二海洋研究所国家海洋局海底科学重点实验室,浙江杭州310012

出　　处：《海洋学报》2014年第6期42-49,共8页

基　　金：国际海底资源调查与开发"十二五"研究课题(DY125-12-R-03);国家自然科学基金项目(91228101;41306056);浙江省杰出青年基金项目(R5110215)

摘　　要：海水中的氦同位素能对海底热液活动进行有效示踪。本文对在西南印度洋49°～56°E洋脊段采集的5条CTD拖曳剖面共14件深水样品进行了氦氖同位素分析。通过分析水体中存在的氦同位素异常，探讨调查区热液异常的特征和热液羽状流的分布。分析表明，5条CTD剖面均存在δ^3He异常，其中CTD7-2（位置：37．927°S、49．412°E，水深2140m，离底高度100m）的δ^3He值最大，达到49．2％。根据δ^3He分布特征，认为调查区内存在至少6处热液羽状流，其中37．927°S、49．412°E以西数千米范围内可能存在海底热液喷口。The helium isotope anomaly in the seawater is a good indicator of the hydrothermal activity in the seafloor. During DY115-21 cruise Leg 7,five CTD Toyo profiles were deployed between 49°E and 56°E on the Southwest Indian Ridge and 14 seawater samples were collected for helium and neon isotope analysis. In this paper, we examine the helium isotope anomalies in the water column and discuss the distribution of the hydrothermal plumes in the investigated area. Our results show that all of the five CTD profiles exhibit distinct 83 He anomalies. Sample CTD7-2 which was sampled at 37. 927°S,49.412°E in the water depth of 2 140 m （100 m above the seafloor） exhibited the largest δ^3He anomaly of 49.2%. According to the distribution pattern of δ^3He,it is suggested that there may existed at least 6 hydrothermal plumes in the investigated area, and one active hydrothermal venting site probably lies within a few kilometers west of 37. 927°S,49. 412°E.

关 键 词：西南印度洋脊 氦同位素异常 热液羽状流 海底热液活动 

分 类 号：P595[天文地球—地球化学]