| Characteristics of platinum-group elements in basalts from spreading axis of Mariana Trough |
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| 作者姓名： | CAO Zhimin ZHENG Jianbin ZHOU Meifu AN Wei QI Liang |
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| 作者单位： | CAO Zhimin1，ZHENG Jianbin1，ZHOU Meifu3，AN Wei2，QI Liang31. College of Marine Geosciences，Ocean University of China，Qingdao 266003，China2. China Offshore Environmental Service Ltd，Tanggu 300452，China3. Department of Earth Sciences，University of Hong Kong，Hong Kong 999077，China |
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| 基金项目： | 国家自然科学基金
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国家高技术研究发展计划(863计划)
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the Key Laboratory of Marine Sedimentology and Environmental Geology
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the State Oceanic Administration
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国家重点基础研究发展计划(973计划) |
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| 摘 要： | Total platinum-group elements (PGEs) abundances in basalts from the spreading axis of Mariana Trough ranged from 0.418×10~(-9) to 1.022×10~(-9), and primitive mantle-normalized PGE patterns are of positive slope showing the relative enrichment of PPGE (platinum,palladium,rhodium) and gold relative to IPGE. Compared with other mantle-originated rocks, these basalts have lower PGE contents and wider ranges of primitive mantle-normalized ratios of palladium content to iridium one,palladium content to platinum one and palladium content to gold one exhibiting relative platinum and iridium depletion. Characteristics of PGE patterns indicated that the studied Mariana Trough basalts originated from low partial melting, and the MORB mantle beneath the spreading center had been contaminated by the arc-island mantle. In the aspect of trace elements, Mariana Trough basalts showed the enrichment of LILE, lead and LREE, indicating that they had been influenced by subduction compositions. All these demonstrated that Mariana Trough basalts are products of partial melting from a mixed mantle (the contamination of MORB mantle by arc-island mantle).
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| 关 键 词： | 马里亚纳群岛 海槽 玄武岩 消减区域 盆地 |
| 收稿时间： | 2006/11/23 0:00:00 |
| 修稿时间： | 2006-11-23 |
Characteristics of platinum-group elements in basalts from spreading axis of Mariana Trough |
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| CAO Zhimin,ZHENG Jianbin,ZHOU Meifu,AN Wei,QI Liang.Characteristics of platinum-group elements in basalts from spreading axis of Mariana Trough[J].Acta Oceanologica Sinica,2007,26(4):63-71. |
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| Authors: | CAO Zhimin ZHENG Jianbin ZHOU Meifu AN Wei and QI Liang |
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| Institution: | 1.College of Marine Geosciences, Ocean University of China, Qingdao 266003, China2.Department of Earth Sciences, University of Hong Kong, Hong Kong 999077, China3.China Offshore Environmental Service Ltd, Tanggu 300452, China |
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| Abstract: | Total platinum-group elements (PGEs) abundances in basalts from the spreading axis of Mariana Trough ranged from 0.418 × 10-9 to 1.022 × 10-9, and primitive mantle-normalized PGE patterns are of positive slope showing the relative enrichment of PPGE (platinum, palladium, rhodium) and gold relative to IPGE. Compared with other mantle-originated rocks, these basalts have lower PGE contents and wider ranges of primitive mantle-normalized ratios of palladium content to iridium one, palladium content to platinum one and palladium content to gold one exhibiting relative platinum and iridium depletion. Characteristics of PGE patterns indicated that the studied Mariana Trough basalts originated from low partial melting, and the MORB mantle beneath the spreading center had been contaminated by the arc-island mantle. In the aspect of trace elements, Mariana Trough basalts showed the enrichment of LILE, lead and LREE, indicating that they had been influenced by subduction compositions. All these demonstrated that Mariana Trough basalts are products of partial melting from a mixed mantle ( the contamination of MORB mantle by arc-island mantle). |
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| Keywords: | back-arc basin basalt platinum-group elements negative platinum anomaly subduction zone basin evolution |
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