概括
塞拉内华达南部的巴托利石显示了时针方向的结构,岩和同位素偏移,表明了构造旋转. 由于板块边界剪切,这种奥洛克林曲可能发生在1600万年前之前.
科学领域:
- 地质物理学 地质物理学
- 结构地质学 结构地质学
- 构造学 构造学 构造学 构造学
背景情况:
- 塞拉内华达巴索利石表现出复杂的结构,岩和同位素特征.
- 之前的研究表明该地区可能存在构造活动.
研究的目的:
- 为了研究塞拉内华达巴索利石的结构和古磁特征.
- 为了测试在内华达山脉南部的奥洛克林曲和构造旋转的假设.
主要方法:
- 来自塞拉内华达巴索利石的结构,岩和同位素数据的分析.
- 在内华达山脉南部的三个地区进行古磁测量.
- 地质绘图和断层分析.
主要成果:
- 结构,岩和同位素特征显示,与中部和北部相比,内华达山脉南部的时钟针方向偏移.
- 古磁数据表明,磁化方向在南方逐渐偏移.
- 在白狼-克恩峡谷断层系统的西北部没有观察到任何显著的古磁偏移.
结论:
- 观察到的偏移与锡埃拉内华达南部区块的构造旋转和奥洛克林曲相一致.
- 口腔曲可能发生在1600万年前之前.
- 这种变形可能是对北美板块西部边界的剪切反应的反应,由斜俯冲引起.
相关概念视频
Unsymmetric Bending - Angle of Neutral Axis
Unsymmetrical bending occurs when a structural member is subjected to bending moments in a plane that does not align with the member's principal axes. This scenario typically arises in beams and other structural components when loads are applied at non-ideal angles, introducing complexities in stress analysis.
When a bending moment is applied at an angle θ concerning the vertical axis of a symmetrical member, it can be resolved into components along the member's principal centroidal axes. The...
When a bending moment is applied at an angle θ concerning the vertical axis of a symmetrical member, it can be resolved into components along the member's principal centroidal axes. The...
Unsymmetric Bending
Unsymmetrical bending occurs when the bending moment applied to a structural member does not align with its principal axis. This misalignment leads to complex stress distributions and deflection patterns that differ from those in symmetrical bending, and are essential for designing structures to withstand different loading conditions. In unsymmetrical bending, the neutral axis—where stress is zero—does not necessarily align with the geometric axes of the cross-section. The orientation of the...
Bending of Curved Members - Neutral Surface
In curved beams, unlike straight beams, the stress distribution across the cross-section is not uniform due to the beam's curvature. This non-uniformity arises because the neutral axis, where stress is zero, does not align with the centroid of the section. In a curved beam, the strain varies along the section as a function of the distance from the neutral axis.
Consider the curved member described in the previous lesson. According to Hooke's law, which relates stress to strain within the...
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Bending of Material: Problem Solving
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Bending
Pure bending is a fundamental concept in structural mechanics, essential for understanding how materials deform under symmetrical loads without direct forces. Pure bending occurs when prismatic members, such as beams, are subjected to equal and opposite moments that induce bending. The phenomenon is crucial as it allows for predicting stress distributions without the influence of axial or shear forces.
In pure bending, the bending stress in a beam is calculated based on the bending moment and...
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Singularity Functions for Bending Moment
Singularity functions simplify the representation of bending moments in beams subjected to discontinuous loading, allowing the use of a single mathematical expression. For a supported beam AB, with uniform loading from its midpoint M to the right side end B, the approach involves conceptual 'cuts' at specific points to determine the bending moment in each segment. By cutting the beam at a point between A and M, the bending moment for the segment before reaching midpoint M is represented using a...


