Change in ice rheology during climate variations – implications for ice flow modelling and dating of the EPICA Dome C core
1Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
2Laboratoire de Glaciologie et de Géophysique de l'Environnement, Saint Martin d'Hères, France
3Alfred Wegener Institute, Bremerhaven, Germany
Abstract. The study of the distribution of crystallographic orientations (i.e., the fabric) along ice cores provides information on past and current ice flow in ice-sheets. Besides the usually observed formation of a vertical single maximum fabric, the EPICA Dome C ice core (EDC) shows an abrupt and unexpected strengthening of its fabric during termination II around 1750 m depth. Such strengthening has already been observed for sites located on an ice-sheet flank. This suggests that horizontal shear could occur along the EDC core. Moreover, the change in the fabric leads to a modification of the effective viscosity between neighbouring ice layers. Through the use of an anisotropic ice flow model, we quantify the change in effective viscosity and investigate its implication for ice flow and dating.
Durand, G., Gillet-Chaulet, F., Svensson, A., Gagliardini, O., Kipfstuhl, S., Meyssonnier, J., Parrenin, F., Duval, P., and Dahl-Jensen, D.: Change in ice rheology during climate variations – implications for ice flow modelling and dating of the EPICA Dome C core, Clim. Past, 3, 155-167, doi:10.5194/cp-3-155-2007, 2007.