ディクリネーションは,マントルのオリビンに富んだ岩石を変形させるために欠けているメカニズムを提供する
Patrick Cordier1, Sylvie Demouchy2, Benoît Beausir3
1Unité Matériaux et Transformations, UMR 8207 CNRS and Université Lille 1, 59650 Villeneuve d'Ascq, France.
Nature
|February 28, 2014
まとめ
傾斜,または回転欠陥は,地球の上層マントルのオリヴィン型変形パラドックスを解決します. この発見は,粒子の境界の可塑性を明らかにし,マントルのレオロギーの多層次モデリングを可能にします.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- マテリアルサイエンス 材料科学
- ミネラル物理学 ミネラル物理学
背景:
- マントルの流れは,ポリミネラル・アグレガート,主にオリヴィンで大きなストレンを伴う.
- オリビンの可塑性反応は,粒子の相互作用と境界の連続性により,アニソトロピックである.
- オリビンの結晶内滑りでは,損傷なしに一般的な変形には不十分であり,パラドックスである.
研究 の 目的:
- オリヴィン型変形パラドックスを解くために,回転欠陥 (ディスクリネーション) を組み込む.
- マントルの流れ中の穀物境界の行動におけるディスクリネーションの役割を調査する.
- 上層マントルのレオロギーの多次元モデリングを可能にする.
主な方法:
- 変形したオリヴィン集積物の高解像度電子反射 difrraction (EBSD) マッピング.
- オリヴィン試料の実験的変形.
- 自然に変形したオリビンのサンプルを分析する.
- オリヴィンにおける高角傾き境界のためのディスクリネーションベースのモデルの開発.
主要な成果:
- 変形したオリビンのEBSDを使用して,不服症が特定され,解決されました.
- 試料と自然サンプルの両方で,粒子の境界を飾る偏斜が観察されました.
- ディスクリネーションベースのモデルは,ディスクリネーション運動によるシェア誘発の穀物境界移動を実証しました.
結論:
- ディスクリネーションは,オリビンのプラスチックフローに欠けているメカニズムを提供する.
- これはオリビンの変形パラドックスを解決し,穀物境界介介介の可塑性を明らかにします.
- この発見により,上層マントルのレオロギーの原子から流れのスケールまでの多層次モデリングが可能になった.
さらに関連する動画
11:50Metal-silicate Partitioning at High Pressure and Temperature: Experimental Methods and a Protocol to Suppress Highly Siderophile Element Inclusions
Published on: June 13, 2015
12.0K
06:04Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 15, 2013
11.3K
関連する概念動画
01:25Imperfections in Crystal Structure: Point, Line and Plane Defects
150
A perfect crystal, in theory, has a uniform structure with the same unit cell and lattice points throughout. However, any deviation from this periodic arrangement is known as an imperfection or defect. These defects can be categorized into three types: point, line, and plane defects.Point defects occur when there is a deviation from the ideal due to missing atoms, displaced atoms, or additional atoms. These imperfections might occur due to imperfect packing during crystallization or because of...
150
01:29Imperfections in Crystal Structure: Non-Stoichiometric Defects
115
Non-stoichiometric defects refer to a type of defect in the crystal structure of a compound where the ratio of its constituent elements deviates from the ideal stoichiometric ratio. There are two main types of non-stoichiometric defects: metal excess defects and metal deficiency defects.Metal excess defects occur when there is a slight surplus of metal ions than what is required by the stoichiometric ratio of the compound. For example, heating a sodium chloride crystal in sodium vapor results...
115
01:26Imperfections in Crystal Structure: Stoichiometric Point Defects
143
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...
143
01:12Temperature Dependent Deformation
742
In a nonhomogeneous rod made up of steel and brass, restrained at both ends and subjected to a temperature change, several steps are involved in calculating the stress and compressive load. Due to the problem's static indeterminacy, one end support is disconnected, allowing the rod to experience the temperature change freely. Next, an unknown force is applied at the free end, triggering deformations in the rod's steel and brass portions. These deformations are then calculated and added...
742
01:18Castigliano's Theorem
1.4K
Castigliano's theorem analyzes displacements and rotations in elastic structures. It relates the derivative of elastic strain energy to the applied forces or moments, allowing for the calculation of deformations. The theorem states that the partial derivative of the total strain energy of a system with respect to a specific load results in the displacement at the point where the load is applied. This principle applies to both forces and moments.
1.4K
02:58Crystal Field Theory - Octahedral Complexes
28.4K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
28.4K