The fate of subducted Upper Continental Crust: An experimental study
The fate of subducted Upper Continental Crust: An experimental study
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俯冲上大陆地壳的命运：一项实验研究
DOI：
10.1016/j.epsl.2009.03.028
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发表时间：
2009-05
影响因子：
5.3
通讯作者：
Wu, Yao
中科院分区：
文献类型：
--
作者：
Fei, Yingwei;Jin, Zhenmin;Liu, Xiaoyang;Wu, Yao
大陆碰撞带岩石中超高压变质（UHPM）指标矿物的出现表明大陆岩石在大陆碰撞过程中可能下降到地球上地幔并留下特定的地球化学标志。长期以来，人们一直认为大陆地壳比地幔岩石具有浮力，因此可能在俯冲过程中被重力捕获。为了了解俯冲大陆地壳的命运和折返，我们在高达24 GPa和1800 °C下，使用活塞-圆柱和多砧装置，对天然超高压变质片麻岩进行了实验研究，其整体成分对应于平均上大陆地壳和陆源岩石。我们发现，上大陆地壳不再是浮力相对于周围的地幔时，它已被运送到250公里（~8-9 GPa）的深度，这定义了俯冲的上大陆地壳的“不归路深度”。这反过来又与大多数暴露的UHPM岩石的深度限制一致。我们的实验结果表明，改造俯冲的上陆壳与硬玉方石英岩岩性有可能陷入过渡带。然而，这种密度关系在过渡带的底部是相反的，留下俯冲的上陆壳被困在上地幔的底部，由于下地幔中钙钛矿和镁橄榄石的存在。
The occurrence of ultra-high pressure metamorphic (UHPM) index minerals within rocks from continental collision zones indicates that continental rocks may descend into the Earth's upper mantle and leave specific geochemical signatures during the continental collision. It has long been suggested that continental crust is buoyant than that of the mantle rocks, and therefore might be gravitationally trapped during subduction. In order to understand the fate and exhumation of subducted continental crust, we conducted experimental studies up to 24 GPa and 1800 °C on natural UHPM gneisses in bulk compositions corresponding to average upper continental crust and terrigenous rocks, using piston-cylinder and multi-anvil apparatus. We found that the upper continental crust is no longer buoyant with respect to the surrounding mantle when it has been transported to a depth of 250 km (~8–9 GPa), which defines the “depth of no return” for the subducted upper continental crust. This in turn is consistent with the depth limit for most exposed UHPM rocks. Our experimental results suggest that the transformed subducted upper continental crust with a jadeite stishovitite lithology has the potential to sink into the transition zone. However, this density relationship is reversed at the base of the transition zone, leaving subducted upper continental crust being trapped at the bottom of the upper mantle, due to the presences of perovskite and magnesiowustite in the lower mantle.
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影响因子：
3.1
作者：
Shuguang Song;Lifei Zhang;J. Chen;J. Liou;Y. Niu
通讯作者：
Shuguang Song;Lifei Zhang;J. Chen;J. Liou;Y. Niu
影响因子：
3.9
作者：
H. Roermund;M. Drury;A. Barnhoorn;A. D. Ronde
通讯作者：
H. Roermund;M. Drury;A. Barnhoorn;A. D. Ronde
影响因子：
5
作者：
K. Domanik;J. Holloway
通讯作者：
K. Domanik;J. Holloway
影响因子：
1.4
作者：
Jianzhong Zhang;Baosheng Li;W. Utsumi;R. Liebermann
通讯作者：
Jianzhong Zhang;Baosheng Li;W. Utsumi;R. Liebermann
影响因子：
5.2
作者：
Yuichiro Sueda;T. Irifune;N. Nishiyama;R. Rapp;T. Ferroir;Tsuyoshi Onozawa;T. Yagi;S. Merkel;N. Miyajima;K. Funakoshi
通讯作者：
Yuichiro Sueda;T. Irifune;N. Nishiyama;R. Rapp;T. Ferroir;Tsuyoshi Onozawa;T. Yagi;S. Merkel;N. Miyajima;K. Funakoshi