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首页> 外文学位 >Kinematic and mechanical evolution of relay zones in normal faulted terranes: Integrating field studies in the Rio Grande rift of north-central New Mexico and three dimensional finite element modeling.
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Kinematic and mechanical evolution of relay zones in normal faulted terranes: Integrating field studies in the Rio Grande rift of north-central New Mexico and three dimensional finite element modeling.

机译：正常断层地层中转带的运动学和力学演化：新墨西哥州中北部里约格兰德裂谷的野外研究和三维有限元建模。

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摘要

The echelon arrangement of normal faults is a fundamental feature of extensional tectonic settings. The interaction between adjacent fault segments is accomplished by displacement transfer through the intervening rock volume referred to as a relay zone. Understanding the evolution of the complex three dimensional deformation in relay zones will give useful insights into the growth of normal faults. In this study, field observations from the Rio Grande rift (RGR) of north-central New Mexico are combined with three dimensional finite element modeling of normal fault interactions to understand the evolution of complex strain and stress fields in relay zones.;The Rio Grande Rift of north-central New Mexico offers all the key elements necessary to develop a numerical model, constrained by field-data, to understand the role of interaction between first order faults in the evolution of regionally extended terranes. Three dimensional elastic-plastic finite element models suggest that relay zones bounded by rectangular faults evolve in a three dimensional strain field, along a non-coaxial strain path. The maximum total extensional strains (S1) are initially deflected from the regional extension direction and rotate towards the regional extension direction with increasing slip on the faults. Therefore, it is dangerous to make traditional assumptions of plane strain deformation within relay zones. The model results suggest that the interaction between the Pajarito fault (PF) and the Sangre de Cristo fault (SCF) in the RGR of north-central New Mexico may have played a major role in the evolution of this segment of the rift.;Generalized three dimensional finite element models of interactions between normal faults bounded by elliptical tiplines suggests that synthetic, antithetic convergent and antithetic divergent relay zones evolve along non-coaxial strain paths. The model results suggest that the fault overlap to spacing ratio, relative orientations of the adjacent faults, coefficient of friction (mu) on the faults and fault tipline shape all exert significant control on the evolution of the strains and stresses in relay zones. The shape of the fault tipline might influence the possible locations of linkage between adjacent normal faults. For relay zones that occur in layered rocks, mechanical stratigraphy plays a major role in the orientations of maximum stretching (S1) vectors in different layers. The refraction of the S1 vectors across adjacent layers is dependent on whether the contact between them is bonded or allowed to slip and on the competence contrast between the adjacent layers. Structural studies of the km scale Hernandez relay zone in the RGR, and of the regional step-over between the PF and SCF have been used to verify the finite element models and to gain additional insights from the models. While field observations can give information about the finite strains and deformed geometry, well correlated numerical models can be used to understand the evolution of particle trajectories and stress vectors and hence provide a mechanical rationale for structures observed in relay zones.
机译：正断层的梯形布置是伸展构造背景的基本特征。相邻断层段之间的相互作用是通过通过称为“中继区”的中间岩石体积的位移传递来实现的。了解中继区域中复杂的三维变形的演变将为正常断层的生长提供有用的见解。在这项研究中，来自新墨西哥州中北部的里奥格兰德裂谷（RGR）的野外观测与正常断层相互作用的三维有限元建模相结合，以了解中继区复杂应变和应力场的演变。新墨西哥州中北部的裂谷提供了开发一个数值模型所必需的所有关键要素，并受到了现场数据的约束，以了解一阶断层之间的相互作用在区域扩展地层演化中的作用。三维弹塑性有限元模型表明，以矩形断层为边界的中继带区域在三维应变场中沿着非同轴应变路径演化。最大的总拉伸应变（S1）首先从区域扩展方向偏转，并随着断层上的滑动增加而向区域扩展方向旋转。因此，对中继区内的平面应变变形进行传统假设是危险的。模型结果表明，新墨西哥州中北部RGR中的Pajarito断层（PF）和Sangre de Cristo断层（SCF）之间的相互作用可能在该裂谷段的演化中起了重要作用。椭圆尖端所界定的正断层之间相互作用的三维有限元模型表明，合成，对立的会聚和对立的发散中继带沿非同轴应变路径演化。模型结果表明，断层重叠率，相邻断层的相对方向，断层上的摩擦系数（μ）和断层尖端形状对断层间应力和应变的演化都具有重要的控制作用。断层尖端线的形状可能会影响相邻正常断层之间链接的可能位置。对于层状岩石中发生的中继带，机械地层学在不同层的最大拉伸（S1）向量的方向上起着主要作用。 S1向量在相邻层之间的折射取决于它们之间的接触是绑定还是允许滑动以及相邻层之间的能力对比。 RGR中km级Hernandez中继带的结构研究以及PF和SCF之间的区域过渡已用于验证有限元模型并从模型中获得更多见解。虽然现场观测可以提供有关有限应变和变形几何的信息，但可以使用高度相关的数值模型来理解粒子轨迹和应力矢量的演变，从而为在中继区观测到的结构提供机械原理。

著录项

  • 作者

    Goteti, Srinivasa Rajesh.;

  • 作者单位

    University of Rochester.;

  • 授予单位 University of Rochester.;
  • 学科 Geology.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 260 p.
  • 总页数 260
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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