Overturned folds in ice sheets: Insights from a kinematic model of traveling sticky patches and comparisons with observations ...

• Main Authors: Wolovick, Michael J., Creyts, Timothy T.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Columbia University 2016
• Subjects: Ice > Dynamics; Formations Geology; Ice sheets; Geophysics; FOS: Earth and related environmental sciences; Physical geography; Greenland; Ice Sheet
• Online Access: https://dx.doi.org/10.7916/d8mw2h7p; https://academiccommons.columbia.edu/doi/10.7916/D8MW2H7P

Overturned folds are observed in regions of the Greenland ice sheet where driving stress is highly variable. Three mechanisms have been proposed to explain these folds: freezing subglacial water, traveling basal slippery patches, and englacial rheological contrasts. Here we explore how traveling basal sticky patches can produce overturned folds. Transitions from low to high stress cause a tradeoff in ice flow between basal slip and internal deformation that deflects ice stratigraphy vertically. If these transitions move, the slip-deformation tradeoff can produce large folds. Those folds record the integrated effects of time-varying basal slip. To understand how dynamic changes in basal slip influence ice sheet stratigraphy, we develop a kinematic model of ice flow in a moving reference frame that follows a single traveling sticky patch. The ice flow field forms a vortex when viewed in the moving reference frame, and this vortex traps ice above the traveling patch and produces overturned folds. Sticky patches ...