Importance of volcanic glass alteration to sediment stabilization; offshore Japan

摘要: A minor amount (ca 1 wt%) of amorphous silica cement sourced from volcanic glass inhibits consolidation hemipelagic sediment approaching the Nankai Trough subduction zone throughout Shikoku Basin. The distribution and nature were examined via secondary backscattered electron imaging. occurs as altered material in contact with glass, coating grains (including grain contacts) filling pores. Based on chemical petrographic evidence, is probably glass; this contrast to a previous suggestion that dominantly biogenic silica. Amorphous disseminated shards has ability form thin clay-dominated Measured content sediments suggests cementing process active Basin (at sites separated by >500 km). cementation may occur other locations where containing hydrated buried sufficiently for heat facilitate alteration (i.e. Central America, Cascadia Gulf Alaska).