CRYSTAL GROWTH RATES AS A FUNCTION OF ORIENTATION

• Main Author: Pounder, E. R.
• Other Authors: MCGILL UNIV MONTREAL (QUEBEC)
• Format: Text
• Language: English
• Published: 1963
• Subjects: (*ICE; CRYSTAL GROWTH); (*CRYSTAL GROWTH; ICE); FREEZING; CRYSTAL STRUCTURE; CONTROLLED ATMOSPHERES; Zumberge; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/AD0452491; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0452491

The results obtained so far certainly do not confirm or disprove the assumption about more rapid growth in basal planes, although most of the 1959 observations are in agreement with it. The anomalous cases are particularly interesting since they indicate the existence of some not yet identified factor that determines which type of crystal will grow more rapidly. Field observations on the crystal structure of sea ice and lake ice show similar differences. The pattern of an annual sea ice cover almost invariably conforms to the type referred to here as normal. That is, the surface layers consist of small, randomly oriented crystals with a strong preference for vertical optic axes, but the bulk of the cover consists of larger crystals with horizontal c-axes. Many reports on lake ice, e. g., Wilson, Zumberge, and Marshall, indicate however that a cover frozen from fresh water consists either of crystals with almost exclusively vertical c-axes or crystals with almost exclusively horizontal c-axes. No satisfactory explanation has been offered. Perey and Pounder observed one similar case in the laboratory. (Author)