Identification of an ancient mantle reservoir and young recycled materials in the source region of a young mantle plume: Implications for potential linkages between plume and plate tectonics
Identification of an ancient mantle reservoir and young recycled materials in the source region of a young mantle plume: Implications for potential linkages between plume and plate tectonics
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识别年轻地幔柱源区的古老地幔储层和年轻的再生材料：对地幔柱和板块构造之间潜在联系的启示
DOI：
10.1016/j.epsl.2013.07.003
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发表时间：
2013-09
影响因子：
5.3
通讯作者：
Li, Xiang-Hui
中科院分区：
文献类型：
--
作者：
Li, Xian-Hua;Li, Jie;Xu, Yi-Gang;Li, Xiang-Hui
地幔柱和板块俯冲是否在遗传上有联系是一个基本的地球科学问题，它影响着我们对地球如何运作的理解。东南亚的晚新生代玄武岩在这个问题上是全球独一无二的，因为它们发生在地震探测到的热羽流上方，与深俯冲板片相邻。在这项研究中，我们提出了新的Pb，Sr，Nd和Os同位素数据的海南溢流玄武岩。结果表明，海南-雷州半岛、中南半岛半岛和南海海山同期玄武岩喷发的低污染玄武岩样品具有相同的同位素地球化学特征。它们具有类似FOZO的Sr、Nd和Pb同位素组成（下地幔的主要成分）。在207 Pb/204 Pb与206 Pb/204 Pb图解上，这些玄武岩具有原始Pb同位素组成，位于或非常接近于4.5- 4.4-Ga的地时线，表明在地球历史早期（4.5-4.4 Ga）存在地幔源区。此外，我们详细的地球化学和Sr，Nd，Pb和Os同位素分析表明，在晚新生代海南地幔柱玄武岩中存在0.5-0.2 Ga的再循环组分。这意味着地幔环流速率大于1厘米/年，这与以前对夏威夷地幔柱的估计相似。这些同步玄武岩源区的古地幔储层和年轻的再生物质的鉴定与地震探测到的下地幔根海南柱相一致，该柱与核幔边界上方的深俯冲板状地震结构相邻。我们推测，持续的深俯冲和存在的致密隔离玄武岩层可能引发了羽从热化学堆上升。因此，这项工作提出了深俯冲和地幔柱生成之间的动态联系。
Whether or not mantle plumes and plate subduction are genetically linked is a fundamental geoscience question that impinges on our understanding of how the Earth works. Late Cenozoic basalts in Southeast Asia are globally unique in relation to this question because they occur above a seismically detected thermal plume adjacent to deep subducted slabs. In this study, we present new Pb, Sr, Nd, and Os isotope data for the Hainan flood basalts. Together with a compilation of published results, our work shows that less contaminated basaltic samples from the synchronous basaltic eruptions in Hainan–Leizhou peninsula, the Indochina peninsula and the South China Sea seamounts share the same isotopic and geochemical characteristics. They have FOZO-like Sr, Nd, and Pb isotopic compositions (the dominant lower mantle component). These basalts have primitive Pb isotopic compositions that lie on, or very close to, 4.5- to 4.4-Ga geochrons on207Pb/204Pb versus206Pb/204Pb diagram, suggesting a mantle source developed early in Earthʼs history (4.5–4.4 Ga). Furthermore, our detailed geochemical and Sr, Nd, Pb and Os isotopic analyses suggest the presence of 0.5–0.2 Ga recycled components in the late Cenozoic Hainan plume basalts. This implies a mantle circulation rate of >1 cm/yr, which is similar to that of previous estimates for the Hawaiian mantle plume. The identification of the ancient mantle reservoir and young recycled materials in the source region of these synchronous basalts is consistent with the seismically detected lower mantle-rooted Hainan plume that is adjacent to deep subducted slab-like seismic structures just above the core–mantle boundary. We speculate that the continued deep subduction and the presence of a dense segregated basaltic layer may have triggered the plume to rise from the thermal–chemical pile. This work therefore suggests a dynamic linkage between deep subduction and mantle plume generation.
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影响因子：
14.9
作者：
S. Shirey;R. Walker
通讯作者：
S. Shirey;R. Walker
影响因子：
5.3
作者：
C. Allègre;E. Lewin
通讯作者：
C. Allègre;E. Lewin
影响因子：
3.5
作者：
H. Zou;Q. Fan
通讯作者：
H. Zou;Q. Fan
影响因子：
2.3
作者：
Dapeng Zhao
通讯作者：
Dapeng Zhao
DOI：
10.1146/annurev-earth-040809-152450
发表时间：
2010-04
影响因子：
14.9
作者：
W. White
通讯作者：
W. White