Structure of the Southern Province, Canadian Shield, inferred from scaled 3-D analogue modelling using viscous and granular materials

1.85 Ga的萨德伯里火成岩杂岩位于加拿大地盾的南部省，特别是在东Penokean造山带（EPO）和钴板块之间的交界处。该复合体是原始水平撞击熔融板的遗迹，在古元古代造山运动中被逆冲和褶皱改变了几何形状。SIC在NW-SE均匀缩短下的非圆柱形折叠的原因尚不清楚。解开这种折叠的运动学需要了解EPO中圆柱形结构的产生，相反，钴板块中的圆顶和盆地。为了解决这些区域尺度上的结构演化问题，提出了用按主要岩性单元的密度、粘度和厚度缩放的层状粘性和颗粒状材料进行模拟实验。实验装置的设计将考虑到古元古代变形的运动学边界条件和单个岩石单元的变形前几何形状对构造演化的影响。将在模型造山带中观察到的结构的几何形状与在自然原型中观察到的结构进行定量比较。阐明圆顶-盆地构造的形成，这是一个在所有时代的造山带中普遍存在的，但在运动学上知之甚少的构造模式，具有普遍的地球动力学意义。

The 1.85 Ga Sudbury Igneous Complex is located in the Southern Province of the Canadian Shield, specifically at the junction between the Eastern Penokean Orogen (EPO) and the Cobalt Plate. The complex is the relic of an originally horizontal impact melt sheet that was geometrically modified by thrusting and folding during Paleoproterozoic orogenesis. The cause for non-cylindrical folding of the SIC under uniform NW-SE shortening is unknown. Unravelling the kinematics of this folding requires an understanding of the generation of cylindrical structures in the EPO and, by contrast, of domes and basins in the Cobalt Plate. In order to resolve the evolution of structures on the scale of these regions, analogue experiments using layered viscous and granular materials scaled to density, viscosity and thickness of major lithological units are proposed. Experimental set-ups will be designed to take into account kinematic boundary conditions of Paleoproterozoic deformation and the influence of the predeformational geometry of individual rock units on the evolution of structures. The geometry of structures observed in model orogens will be quantitatively compared to those observed in the natural prototype. Elucidating the formation of dome-and-basin structure, an ubiquitous, yet kinematically little understood structural pattern in orogenic belts of all ages, is of general geodynamic importance.