High‐resolution image of the geometry and thickness of the subducting Nazca lithosphere beneath northern Chile
High‐resolution image of the geometry and thickness of the subducting Nazca lithosphere beneath northern Chile
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智利北部俯冲纳斯卡岩石圈的几何形状和厚度的高分辨率图像
DOI：
10.1029/2010jb007829
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发表时间：
2011
影响因子：
--
通讯作者：
Kind R.
中科院分区：
文献类型：
--
作者：
Sodoudi F;Yuan X;Asch G;Kind R.
从sandpreceiver函数获得的结果产生了智利北部纳斯卡岩石圈俯冲顶部和底部的清晰图像。利用智利15个永久集成板块边界观测站（IPOC）记录的远震事件数据，我们获得了纳斯卡岩石圈下降的几何形状和厚度的新约束条件。我们观察了纳斯卡板块俯冲地壳的深度，从沿海科迪勒拉下50公里到西科迪勒拉下110公里。我们发现智利北部纳斯卡板块的几何形状沿走向有显著的变化。仔细观察，海洋纳斯卡板块似乎被分成两个不同的部分，因为它下降到南美洲大陆板块之下。我们的数据相当清楚地显示了从21°S以北相对陡峭（~ 23°）和较深的板块到较平坦的南段（~ 19°）的转变。这一特征很可能与板块边缘曲率的变化和智利海沟的几何形状有关，智利海沟主要向南纬21°以北弯曲。我们还绘制了南美板块在纵向谷以东60至70公里深处的莫霍大陆图。在海岸科迪勒拉之下，这个边界变得不可见，可能是由于弧前地幔楔的蛇纹石化，降低了最上层地幔的速度。pandsreceiver函数的结果表明，纳斯卡板块的俯冲基底是一个明显的边界。年龄为~ 50万年的纳斯卡洋俯冲板块的厚度估计为~ 50公里。虽然这种厚度与热梯度预测的厚度一致，但岩石圈-软流圈边界的清晰度可能需要另一种机制，如水化或融化。
Results obtained fromSandPreceiver functions produced a clear image of the top and bottom of the subducting Nazca lithosphere beneath northern Chile. Using data from the teleseismic events recorded at 15 permanent Integrated Plate Boundary Observatory Chile (IPOC) stations, we obtained new constraints on the geometry and thickness of the descending Nazca lithosphere. We observed the subducted crust of the Nazca plate at depths ranging from 50 km beneath the Coastal Cordillera down to 110 km beneath the Western Cordillera. We found significant along‐strike variations in the geometry of the Nazca plate beneath northern Chile. On closer inspection, it appears that the oceanic Nazca plate is divided into two distinct segments as it descends beneath the continental South American plate. The transition from the relatively steeper (∼23°) and deeper slab to the north of 21°S to the flatter southern segment (∼19°) is shown reasonably clearly by our data. This feature could well be associated with variations in the curvature of the plate margin and the geometry of the Chile trench, which is mainly curved to the north of 21°S. We have also mapped the continental Moho of the South American plate at depths ranging between 60 and 70 km to the east of the Longitudinal Valley. Beneath the Coastal Cordillera, this boundary becomes invisible, probably due to the serpentinization of the forearc mantle wedge that reduces the velocity in the uppermost mantle. The base of the subducted Nazca plate was clearly identified as a sharp boundary in the results obtained from thePandSreceiver functions. The thickness of the subducted oceanic Nazca plate, which has an age of ∼50 My, is estimated to be ∼50 km. Although this thickness is consistent with that predicted by thermal gradients, the explanation of the sharpness of the lithosphere‐asthenosphere boundary may require another mechanism such as hydration or melting.
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影响因子：
2.9
作者：
S. Buske;S. Lüth;H. Meyer;R. Patzig;C. Reichert;S. Shapiro;P. Wigger;M. Yoon
通讯作者：
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DOI：
--
发表时间：
2000
期刊：
影响因子：
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DOI：
--
发表时间：
2001
期刊：
影响因子：
--
作者：
C. Haberland;A. Rietbrock
通讯作者：
A. Rietbrock
影响因子：
5.2
作者：
B. Heit;F. Sodoudi;X. Yuan;M. Bianchi;R. Kind
通讯作者：
B. Heit;F. Sodoudi;X. Yuan;M. Bianchi;R. Kind
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DOI：
--
发表时间：
1995
期刊：
影响因子：
--
作者：
D. Comte;G. Suárez
通讯作者：
G. Suárez