MICROSCOPIC OBSERVATIONS OF THE AIR HYDRATE-BUBBLE. TRANSFORMATION PROCESS IN GLACIER ICE

• Main Authors: Shoji, H., Langway, C., Jr
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1987
• Subjects: [PHYS.HIST]Physics [physics]/Physics archives; Greenland; Byrd; Byrd Station; Antarc*; Antarctica; Dye 3; Dye-3; glacier; ice core
• Online Access: https://hal.science/jpa-00226321; https://hal.science/jpa-00226321/document; https://hal.science/jpa-00226321/file/ajp-jphyscol198748C175.pdf; https://doi.org/10.1051/jphyscol:1987175

Microscopie examinations for air hydrate inclusions were made on specimens of the Dye-3 and Camp Century, Greenland and Byrd Station, Antarctica deep ice cores. The shallowest depths at which air hydrates are observed in the Dye-3, Camp Century and Byrd Station cores are at 1092 m, 1099 m and 727 m depths respectively. For the Dye-3 and Camp Century cores, the observed depths for air hydrate appearance agree with Miller's calculation [1]. For the Byrd Station core, the observed depth for the appearance is about 100 m shallower than the calculation result by Miller. This apparent difference at Byrd Station may be attributed to the general upward ice flow trajectory which begins about 5 km upstream from the Byrd Station location. The phase/grain boundary observations and deformation experiments revealed that phase boundary energy is much higher than grain boundary energy and that the transformation process from air hydrate to bubble is clearly related to the strain-induced nucleation process. These findings suggest that the air hydrate/bubble transformation process is strongly controlled by both in situ and post ice core recovery nucleation activation process.