Folding and boudinage of an oblique single layer

斜单层的折叠和布丁

基本信息

批准号：
320143187
负责人：
Professor Dr. Gernold Zulauf
金额：
--
依托单位：
Arbeitsgruppe Strukturgeologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/320143187?language=en
关键词：
Folding boudinage oblique single layer

项目摘要

Folds and boudins provide information on strain, rheology and deformation history of rocks. That is why the conditions during which both structures develop should be well known. Nearly all the theory and modelling of folds and boudins are based on coaxial deformation of a layer (or layers) oriented perpendicular to the principal strain axes. Under such conditions folds and boudins grow simultaneously or develop separately as single structures. The situation, however, is entirely different and more complex if the layering is oblique to all three far-field principal strain rates. In such cases the directions of maximum shortening rate in the competent layer varies continuously with time and the base strain rate on which a buckling or necking instability would be superimposed is therefore also changing. Consequently, folds and boudins may develop in sequence. As experimental evidence for sequential growth of both structures is lacking, we will carry out scaled experiments using non-linear viscous rock analogues to show the impact of layer inclination on the deformation geometry. The main aim is to constrain the conditions (viscosity ratio, layer inclination, finite strain) which are suitable for the sequential development of folds and boudins (or pinch-and-swell structures) under bulk coaxial plane strain. It will further be shown how folding will change to boudinage (and vice versa) when the attitude of the layer is changing. As folding and boudinage of an oblique competent layer is common in various settings (e.g. orogens, salt domes), the present project will be of interest for a large number of structural geologists, who can use the new results to constrain the conditions of folding and boudinage in natural environments.

褶皱和布丁提供有关岩石的应变，流变学和变形历史的信息。这就是为什么两种结构都应该众所周知的条件。几乎所有的褶皱和boudins的理论和建模都是基于垂直于主应变轴的层（或层）的同轴变形。在这种条件下，折叠和包粉同时生长或单独发展为单个结构。但是，如果分层与所有三个远场主应变率倾斜，则情况是完全不同的，并且更为复杂。在这种情况下，主管层中最大缩短速率的方向随时间而连续变化，因此，屈曲或颈部不稳定性的基本应变速率也会变化。因此，褶皱和boudins可能会顺序发展。由于缺乏两种结构顺序生长的实验证据，我们将使用非线性粘性岩石类似物进行缩放实验，以显示层倾斜度对变形几何形状的影响。主要目的是限制适用于在大量同轴平面应变下的褶皱和boudins（或捏杆结构）的顺序发展的条件（粘度比，层倾斜度，有限应变）。将进一步显示，当层的态度发生变化时，折叠将如何变为boudinage（反之亦然）。由于在各种环境（例如Orogens，盐圆顶）中很常见倾斜胜任层的折叠和凸轮，因此对于大量结构地质学家来说，本项目将引起人们的关注，他们可以使用新的结果来限制折叠和折叠条件和自然环境中的boudinage。