Accommodation of penetrative strain during deformation above a ductile décollement
Accommodation of penetrative strain during deformation above a ductile décollement
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在延性脱脱上方变形期间调节渗透应变
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
C. Burberry
中科院分区：
文献类型：
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作者：
B. Lathrop;C. Burberry
渗透应变对缩短的调节作用被广泛认为是收缩过程中的一个重要过程，但对于具有韧性滑脱的收缩系统中渗透应变的分布和大小还没有很好的认识。渗透应变构成了整个造山带总缩短量的比例，该比例不受宏观结构（例如褶皱和逆冲断层）发育的影响。为了建立一个框架，了解渗透应变在脆性系统以上的韧性滑脱，8个模拟模型，每个具有相同的初始配置，缩短到不同的量在变形装置。模型由硅聚合物基底层和三层细粒砂层组成。在表面上压印网格以跟踪缩短期间的渗透应变。随着模型的缩短，一系列的箱形褶皱结构发展起来，在前陆有一个穿透应变带。前陆的渗透应变在远离褶皱带处减小。模型层水平恢复表明，在韧性滑脱的脆性系统中，穿透应变占总缩短量的90.5%-30.8%，而在完全脆性系统中，穿透应变占总缩短量的45.2%-3.6%。模拟模型的几何形状是一致的，在盐雾系统，如瑞士汝拉观察到的变形风格。渗透应变尚未占在以前的研究中的盐浸地区和这种类型的估计可能有助于解决全球定位系统数据突出的缺失缩短的关注。
The accommodation of shortening by penetrative strain is widely considered as an important process during contraction, but the distribution and magnitude of penetrative strain in a contractional system with a ductile decollement are not well understood. Penetrative strain constitutes the proportion of the total shortening across an orogen that is not accommodated by the development of macroscale structures, such as folds and thrusts. In order to create a framework for understanding penetrative strain in a brittle system above a ductile decollement, eight analog models, each with the same initial configuration, were shortened to different amounts in a deformation apparatus. Models consisted of a silicon polymer base layer overlain by three fine-grained sand layers. A grid was imprinted on the surface to track penetrative strain during shortening. As the model was shortened, a series of box fold structures developed, with a zone of penetrative strain in the foreland. Penetrative strain in the foreland decreases away from the fold belt. Restoration of the model layers to the horizontal indicates that penetrative strain accounts for 90.5%–30.8% of total shortening in a brittle system with a ductile decollement, compared to 45.2%–3.6% within a totally brittle system. Analog model geometries were consistent with the deformation styles observed in salt-floored systems, such as the Swiss Jura. Penetrative strain has not been accounted for in previous studies of salt-floored regions and estimates of this type could help resolve concerns of missing shortening highlighted by global positioning system data.