Subduction of the primordial crust into the deep mantle
Subduction of the primordial crust into the deep mantle
复制标题
原始地壳俯冲到地幔深处
DOI：
10.1016/j.gsf.2016.08.003
复制
发表时间：
2017
影响因子：
8.9
通讯作者：
Ichikawa H.. Greaux S. and Azuma S.
中科院分区：
文献类型：
--
作者：
Hidekazu Tanaka;Kazuhiro Kanagawa;Murakawa Koji;Ichikawa H.. Greaux S. and Azuma S.
地球的原始地壳是由冥古宙地表岩浆海洋结晶形成的。然而，地质调查并未发现地球表面存在 4 Ga 以上岩石的证据，这表明冥古宙地壳因某些过程而消失。我们研究了类似于月球的原始地壳、斜长岩和克里普地壳的可能候选者之一的俯冲作用，这些地壳也被认为是由岩浆海洋的结晶形成的。与现在的地球类似，俯冲侵蚀对原始地壳的俯冲有望成为消除地表原始地壳的有效途径。在这项研究中，通过数值模拟评估了原始地壳通过俯冲通道的俯冲速率。俯冲通道位于俯冲板片和地幔楔之间，由主要由俯冲侵蚀提供的原始地壳物质组成。我们发现，地球表面厚约 50 公里的原始斜长岩和克里普地壳能够通过这种机制在 0.1-2 Gy 内传送到地幔深处。
The primordial crust on the Earth formed from the crystallization of the surface magma ocean during the Hadean. However, geological surveys have found no evidence of rocks dating back to more than 4 Ga on the Earth's surface, suggesting the Hadean crust was lost due to some processes. We investigated the subduction of one of the possible candidates for the primordial crust, anorthosite and KREEP crust similar to the Moon, which is also considered to have formed from the crystallization of the magma ocean. Similar to the present Earth, the subduction of primordial crust by subduction erosion is expected to be an effective way of eliminating primordial crust from the surface. In this study, the subduction rate of the primordial crust via subduction channels is evaluated by numerical simulations. The subduction channels are located between the subducting slab and the mantle wedge and are comprised of primordial crust materials supplied mainly by subduction erosion. We have found that primordial anorthosite and KREEP crust of up to ∼50 km thick at the Earth's surface was able to be conveyed to the deep mantle within 0.1-2 Gy by that mechanism.