主动地幔上升的稳定性由板块构造学净特征揭示出来
Clinton P Conrad1, Bernhard Steinberger, Trond H Torsvik
1Department of Geology and Geophysics, SOEST, University of Hawaii at Mānoa, Honolulu, Hawaii 96822, USA. clintc@hawaii.edu
Nature
|June 28, 2013
概括
全球地幔流动模式可以通过分析构造板块运动来揭示. 这项研究重建了过去的板块运动,以了解地球深层动态和长期地幔上升.
科学领域:
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
- 地球科学 地球科学 地球科学
背景情况:
- 地幔对流驱动构造板块运动和表面变形.
- 由于历史数据有限,调查过去的地幔流是具有挑战性的.
- 表面地质与地球历史上深层地幔动态密切相关.
研究的目的:
- 从表面板块运动中推断出全球范围的地幔流动的时间依赖性.
- 为了研究板块构造学和地幔动力学之间的历史关系.
- 为了确定地幔上游的长期稳定性.
主要方法:
- 计算板块运动的双极和四极时刻,使用到中生纪早期的构造结构重建.
- 对度1和2的净收和分歧的跟踪地理位置.
- 盘子运动特征的比较方向与底层地幔流动模式.
主要成果:
- 当今的板块运动显示东亚的双极融合,非洲中部和太平洋中部的四极分离.
- 这些板块运动特征与底层地幔流动模式密切匹配.
- 在过去的2.5亿年里,四极分离位置一直保持稳定,这表明地幔持续上升.
结论:
- 表面板块运动的净特征作为深层地幔流动模式的指标.
- 在非洲和太平洋下方稳定的地幔上游可能由不同的最下层地幔区域组织起来.
- 这项研究提供了对地幔动态的长期演变及其对地球表面的影响的见解.
相关概念视频
Stability
The time response of a linear time-invariant (LTI) system can be divided into transient and steady-state responses. The transient response represents the system's initial reaction to a change in input and diminishes to zero over time. In contrast, the steady-state response is the behavior that persists after the transient effects have faded.
The stability of an LTI system is determined by the roots of its characteristic equation, known as poles. A system is stable if it produces a bounded...
The stability of an LTI system is determined by the roots of its characteristic equation, known as poles. A system is stable if it produces a bounded...
Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...
Energy Diagrams - II
Energy diagrams are important to understand the dynamics of a system. The topology of an energy diagram helps illustrate the equilibrium points of the system.
The point in the energy diagram at which the system’s potential energy is the lowest is known as the local minima. The system tends to stay in this position indefinitely unless acted upon by a net force. The slope of the potential energy diagram at the local minima is zero, indicating that zero net force is acting on the system. The slope...
The point in the energy diagram at which the system’s potential energy is the lowest is known as the local minima. The system tends to stay in this position indefinitely unless acted upon by a net force. The slope of the potential energy diagram at the local minima is zero, indicating that zero net force is acting on the system. The slope...
Pole and System Stability
The transfer function is a fundamental concept representing the ratio of two polynomials. The numerator and denominator encapsulate the system's dynamics. The zeros and poles of this transfer function are critical in determining the system's behavior and stability.
Simple poles are unique roots of the denominator polynomial. Each simple pole corresponds to a distinct solution to the system's characteristic equation, typically resulting in exponential decay terms in the system's response.
Simple poles are unique roots of the denominator polynomial. Each simple pole corresponds to a distinct solution to the system's characteristic equation, typically resulting in exponential decay terms in the system's response.
Microbial Mats
Microbial communities forming biofilms and mats represent complex, spatially structured ecosystems where metabolic processes are stratified according to light, oxygen, and nutrient gradients. Biofilms are initial colonization stages, only a few millimeters thick, while mature microbial mats can reach centimeter-scale thickness and display intricate vertical organization. Their structural and functional heterogeneity allows microorganisms to occupy distinct ecological niches within a few...
Stability of Equilibrium Configuration
Understanding the stability of equilibrium configurations is a fundamental part of mechanical engineering. In any system, there are three distinct types of equilibrium: stable, neutral, and unstable.
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...


