Characterizing fabric associated with folding in the Greenland NEEM ice core

The North Greenland EEMian Ice Drilling (NEEM) ice core drilled during 2008-2012 contains the first recoverable fold ever reported in an ice core (NEEM community members, 2013). The folding caused certain time periods recorded in the ice core to appear multiple times and upside down (Figure 1). Recent new observations from deep ice penetrating radar images collected by NASA's IceBridge Program show that folding of the deep layers is relatively common across central and northern Greenland (Dahl-Jensen, et al., 2012) – an observation that has made the ice sheet modeling community reconsider how they treat the flow of ice in their models. Models such as UAF's Parallel Ice Sheet Model (PISM) consider ice as a homogeneous material and do not incorporate this folding behavior or its effects on ice deformation mechanics. The incorporation of folding behavior into ice-sheet models could improve past configuration reconstructions, and in turn lead to greater confidence in predicted future ice-sheet evolution and deformation scenarios. This proposal covers the first steps toward answering the question: how important is the folding process to ice sheet models like PISM? This project will answer the following specific questions: How is folding manifested in the fabric? What information does fabric provide about folding (including relative timing or deformation rates)?