Glacier surging provides a window into the processes responsible for some of the fastest ice flow on Earth. Surge-type glaciers are festooned with fold trains—many visible from space—which encode the history of polyphase deformation associated with this form of episodic fast flow. We conduct the first investigation of the kinematic evolution of these kilometre-scale folds using a full-Stokes numerical ice-flow model. We model the folds through multiple surge cycles within a set of synthetic glacier confluence configurations, and identify how differences in glacier flow regimes imprint themselves on three-dimensional fold geometry. Based on simulation results across parameter space, we present an archetype of kinematic evolution that describes the transition from cylindrical vertically plunging gentle folds emplaced during the surge phase, to complex depth-varying folds following multiple cycles of surging and quiescent flow. A detailed examination of the surface trace of these folds highlights the links between glacier flow regime and folding. The initial fold geometry is controlled by longitudinal and lateral shear stress regimes during surging, while fold evolution is governed primarily by lateral shearing after emplacement. This reflects the influence of valley geometry and glacier dynamics on the variability of flow regimes during both surging and quiescent flow. Finally, we illustrate the potential of our approach to reconstruct more complex fold geometries as observed in nature.

冰川涌动为了解地球上一些最快冰流的过程提供了一个窗口。涌动型冰川上装饰着褶皱链——许多从太空中可见——它们编码了与这种间歇性快速流动相关的多相变形的历史。我们使用全斯托克斯数值冰流模型对这些千米级褶皱的运动学演化进行了首次调查。我们通过一组合成冰川汇合配置中的多个浪涌周期对褶皱进行建模，并确定冰川流动状态的差异如何在三维褶皱几何图形上留下印记。基于跨参数空间的模拟结果，我们提出了运动学演化的原型，该原型描述了在浪涌阶段从圆柱形垂直下沉平缓褶皱的过渡，在多次涌流和静止流循环之后复杂的深度变化褶皱。对这些褶皱的表面痕迹的详细检查突出了冰川流动状态和褶皱之间的联系。初始褶皱几何形状受涌动期间的纵向和横向剪应力控制，而褶皱演化主要受就位后的横向剪切控制。这反映了山谷几何形状和冰川动力学对涌流和静止流期间流态变化的影响。最后，我们说明了我们的方法在重建自然界观察到的更复杂的折叠几何形状的潜力。初始褶皱几何形状受涌动期间的纵向和横向剪应力控制，而褶皱演化主要受就位后的横向剪切控制。这反映了山谷几何形状和冰川动力学对涌流和静止流期间流态变化的影响。最后，我们说明了我们的方法在重建自然界观察到的更复杂的折叠几何形状的潜力。初始褶皱几何形状受涌动期间的纵向和横向剪应力控制，而褶皱演化主要受就位后的横向剪切控制。这反映了山谷几何形状和冰川动力学对涌流和静止流期间流态变化的影响。最后，我们说明了我们的方法在重建自然界观察到的更复杂的折叠几何形状的潜力。