Generation of continental intraplate alkali basalts and implications for deep carbon cycle
Generation of continental intraplate alkali basalts and implications for deep carbon cycle
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大陆板内碱性玄武岩的生成及其对深部碳循环的影响
DOI：
10.1016/j.earscirev.2019.103073
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发表时间：
2020-02
影响因子：
12.1
通讯作者：
Yuan Huaiyu
中科院分区：
文献类型：
--
作者：
Xu Rong;Liu Yongsheng;Wang Xuan-Ce;Foley Stephen F.;Zhang Yanfei;Yuan Huaiyu
尽管已提出深层碳的回收利用在产生板岩内岩浆中发挥关键作用，但它如何控制或触发地幔融化的问题仍然很熟悉。此外，地幔中的初期碳酸熔体及其随后与地幔的反应是可能影响板岩内玄武岩地球化学的关键过程，但是此类过程的细节也不清楚。在这里，我们提供了地球化学证据表明，在碳植物内部的大陆内层中存在普遍的碳酸盐融化，高度碱性玄武岩（Sio2 <45 wt％），这些底层较小，但在中国东部广泛但广泛。这些底层的主要岩浆组成不能通过对单一地幔来源岩性的部分融化或源自不同地幔来源的岩浆的混合来解释，但是可以通过碳酸盐液融化的碳酸盐融化来充分说明碱岩浆。碳酸盐的来源是与太平洋板相关的俯冲叶绿树，该板块停滞在地幔过渡区（MTZ）中。碱玄武岩的空间分布与MTZ上方的上地幔中的大规模地震低速异常一致。西北中部和澳大利亚东部的类似情况使我们提出，碳酸二氧化硅富含熔融和橄榄岩之间的反应可能是世界其他地方其他地方的大陆板岩内碱性玄武岩的关键机制。
Although the deep recycling of carbon has been proposed to play a key role in producing intraplate magmatism, the question of how it controls or triggers mantle melting remains poorly understood. In addition, generation of incipient carbonated melts in the mantle and their subsequent reaction with the mantle are critical processes that can influence the geochemistry of intraplate basalts, but the details of such processes are also unclear. Here we present geochemical evidence for the existence of pervasive carbonate melt in the mantle source of Cenozoic continental intraplate highly alkali basalts (SiO2 < 45 wt%), which are volumetrically minor but widespread in eastern China. The primary magma compositions of these basalts cannot be explained by either partial melting of a single mantle source lithology or mixing of magmas derived from distinct mantle sources, but can be adequately explained by carbonate-fluxed melting of eclogite and subsequent reaction between silica-rich melts and peridotite that ultimately transformed the initial carbonated silica-rich melts into silica-undersaturated alkalic magmas. The source of the carbonate is in subducted eclogites associated with the Pacific plate, which stagnated in the mantle transition zone (MTZ). The spatial distribution of the alkali basalts is in accord with large-scale seismic low-velocity anomalies in the upper mantle above the MTZ. Similar scenarios in central-western Europe and eastern Australia lead us to propose that reaction between carbonated silica-rich melt and peridotite may be a pivotal mechanism for the generation of continental intraplate alkali basalts elsewhere in the world.
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影响因子：
3.9
作者：
Gerbode, Christine;Dasgupta, Rajdeep
通讯作者：
Dasgupta, Rajdeep
影响因子：
5.2
作者：
Coltice, N;Simon, L;Lécuyer, C
通讯作者：
Lécuyer, C
影响因子：
3.9
作者：
Dasgupta, Rajdeep;Hirschmann, Marc M.;Withers, Anthony C.
通讯作者：
Withers, Anthony C.
影响因子：
2.3
作者：
Dapeng Zhao
通讯作者：
Dapeng Zhao
影响因子：
18.3
作者：
Brunelli, Daniele;Cipriani, Anna;Bonatti, Enrico
通讯作者：
Bonatti, Enrico