Ice H
2O Hexagonal
o Parametamorphic environment (chapters 14 and 18)
- Thin sections (XP) of Antarctic ice from the Taylor Dome ice core recovered in 1993. Firn-ice transition in this core is at 72 m. Thick sections cut normal to vertical core. Maximum presenting interference color blue-green is generated by crystals in which crystallographic c lies flat in the section. Since the birefringence (maximum) of ice is very low (dark gray) at standard 30 micron thickness, the sections were prepared considerably thicker in order to generate interference colors (including shades of gray) useful as indicators of crystal orientation. Fabrics in both samples are fairly well polygonalized. Note trapped air bubbles in both samples. Photos provided by J. Fitzpatrick and S. Jacobson (National Ice Core Laboratory/U.S.G.S.).
(A) Coarser-grained (crystals mostly 3 cm) sample, retrieved from a depth of 411.5 m, indicates on-going recrystallization accompanied by grain rotation by means of slip on (001). This yielded near vertical orientation of crystallographic c, as indicated by the very low birefringence in most grains.
(B) Finer-grained (crystals mostly 1.5 cm) sample, retrieved from a depth of 180.1 m, has little or no preferred crystal orientation, reflecting the lower deviatoric stress environment.
feedback form |
permissions |
international |
locate your campus rep |
request a review copy
digital solutions |
publish with us |
customer service |
mhhe home
Copyright ©2001 The McGraw-Hill Companies.
Any use is subject to the
Terms of Use and Privacy Policy.
McGraw-Hill Higher Education is one of the many fine businesses of the
The McGraw-Hill Companies.
