A better knowledge of boundary conditions near a grounding line is critical for understanding the behavior of ice shelves and floating glaciers. We show here that significant information can be gained from a high-resolution isotopic and textural study of marine ice accreted at the bottom of a floating glacier near its grounding line. Two different types of marine ice have been found. Type 1 is bubble- and debris-free ice with properties which, we believe, can be explained by intrusion of brackish water in open basal fissures. Closing of the fissures by progression of a freezing front from the sides is precluded, and filling by frazil ice is favored. Type 2 is made of thin, clear ice and debris layers which are thought to have formed when a subglacial water-filled sediment enters into contact with seawater and is subjected to freezing under a double-diffusion process. The paper also stresses that in a delta D-delta(18)O diagram the alignment of marine ice samples on a mixing line does not necessarily imply a mixture of continental water and seawater in varying proportions
Souchez, R., Tison, J., Lorrain, R., Fléhoc, C., Stiévenard, M., Jouzel, J., et al. (1995). Investigating processes of marine ice formation in a floating ice tongue by a high‐resolution isotopic study. JOURNAL OF GEOPHYSICAL RESEARCH: OCEANS, 100(C4), 7019-7025 [10.1029/95JC00142].
Investigating processes of marine ice formation in a floating ice tongue by a high‐resolution isotopic study
MAGGI, VALTER
1995
Abstract
A better knowledge of boundary conditions near a grounding line is critical for understanding the behavior of ice shelves and floating glaciers. We show here that significant information can be gained from a high-resolution isotopic and textural study of marine ice accreted at the bottom of a floating glacier near its grounding line. Two different types of marine ice have been found. Type 1 is bubble- and debris-free ice with properties which, we believe, can be explained by intrusion of brackish water in open basal fissures. Closing of the fissures by progression of a freezing front from the sides is precluded, and filling by frazil ice is favored. Type 2 is made of thin, clear ice and debris layers which are thought to have formed when a subglacial water-filled sediment enters into contact with seawater and is subjected to freezing under a double-diffusion process. The paper also stresses that in a delta D-delta(18)O diagram the alignment of marine ice samples on a mixing line does not necessarily imply a mixture of continental water and seawater in varying proportionsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.