The evolution of crystal fabric in ice sheets and its link to climate history

JOSEPH H KENNEDY; ERIN PETTIT; C. L. DI PRINZIO

JOURNAL OF GLACIOLOGY

INT GLACIOL SOC

Lugar: London; Año: 2013 vol. 59 p. 1 - 23

0022-1430

The evolution of preferred crystal-orientation fabrics is strongly sensitive to the initialfabric and texture. A perturbation in climate can induce variations in fabric and texture in the firn.Feedbacks between fabric evolution and ice deformation can enhance these variations through time anddepth in an ice sheet. We model the evolution of fabric under vertical uniaxial-compression and pureshearregimes typical of ice divides. Using an analytic anisotropic flow law applied to an aggregate ofdistinct ice crystals, the model evolves the fabric and includes parameterizations of crystal growth,polygonization and migration recrystallization. Stress and temperature history drive the fabricevolution. Using this model, we explore the evolution of a subtle variation in near-surface fabricusing both constant applied stress and a stress–temperature history based on data from Taylor Dome,East Antarctica. Our model suggests that a subtle variation in fabric caused by climate perturbations willbe preserved through time and depth in an ice sheet. The stress history and polygonization rate primarilycontrol the magnitude of the preserved climate signal. These results offer the possibility of extractinginformation about past climate directly from ice fabrics.