Siple Dome, located at 81.658 S, 148.818W in West

• Main Authors: Anthony J. Gow, Debra A. Meese, Bindschadler Ice, Streams (former Ice Streams C
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1999
• Subjects: Byrd; East Antarctica; Greenland; Mount Berlin; Siple; Siple Dome; Antarc*; Antarctica; Greenland Ice Sheet Project; ice core; Ice Sheet
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.634.6093; http://www.igsoc.org/journal/53/183/j06j072.pdf

ABSTRACT. Approximately 300 volcanic ash and dust layers were observed in the Siple Dome (Antarctica) ice core. Most of this tephra, deposited between 700 and 800m depth, consisted primarily of glass shards with varying amounts of crystalline material and groundmass fragments. The pattern of distribution of tephra fallout closely replicates that found in the Byrd ice core, indicative of contemporaneous deposition at both locations. Peak fallout occurred approximately 19 500 years ago, based on methane tie points in the Siple Dome and Greenland Ice Sheet Project 2 (GISP2) ice cores. Mount Berlin was identified as a potential source of tephra, although other volcanoes in West and East Antarctica appear to have contributed ash and dust. Ice between 697 and 730m, in which fine-grained tephra is concentrated, has undergone enhanced thinning compared to ice with a similar concentration of tephra deposited contemporaneously between 1300 and 1540m at Byrd. It is speculated that this thinning has occurred in response to dynamic interaction between ice at Siple Dome and the two ice streams flanking it. A dramatic change to a shear fabric appears to be directly related to the higher concentration of volcanic particles in the ice between 700 and 800m.