5. Data Report: Textural Variation of Units 1256C-18 and 1256D-1 Lava Pond, with Special Reference to Recrystallization of the Base of Unit 1256C-181

Susumu Umino2

INTRODUCTION

Hole 1256C was cored 88.5 m into basement, and Hole 1256D, the deep reentry hole, was cored 502 m into basement during Ocean Drilling Program Leg 206. Hole 1256D is located ~30 m south of Hole 1256C (Wilson, Teagle, Acton, et al., 2003). A thick massive flow drilled in both holes, Units 1256C-18 and 1256D-1, consists of a single cooling unit of cryptocrystalline to fine-grained basalt, interpreted as a ponded lava, 32 m and at least 74.2 m thick, respectively. This ponded flow gives us a unique opportunity to examine textural variations from the glassy, folded crust of the lava pond recovered from the top of Unit 1256C-18 through the coarse-grained, thick massive lava body to the unusually recrystallized and deformed base cored in Unit 1256C-18. Some detailed descriptions of the textures and grain size variations through the lava pond (Units 1256C-18 and 1256D-1), with special reference to the recrystallization of the base of Unit 1256C-18, are presented here.

1Umino, S., 2007. Data report: textural variation of Units 1256C-18 and 1256D-1 lava pond, with special reference to recrystallization of the base of Unit 1256C-18. In Teagle, D.A.H., Wilson, D.S., Acton, G.D., and Vanko, D.A. (Eds.), Proc. ODP, Sci. Results, 206: College Station, TX (Ocean Drilling Program), 1–32. doi:10.2973/odp.proc.sr.206.007.2007

2Institute of Geosciences, Shizuoka University, Ohya 836, Suruga-ku, Shizuoka 422-8529, Japan. sesumin@ipc.shizuoka.ac.jp

Initial receipt: 2 May 2005
Acceptance: 5 September 2006
Web publication: 5 March 2007
Ms 206SR-007

NEXT