IODP Proceedings, Volume 335
Expedition 335 summary, Table T5. Key parameters for Hole 1256D and preliminary subdivisions of the upper oceanic crust at Site 1256 adopted for Expedition 335.

This table is available in ASCII and in Microsoft Excel format (see 101_T05.XLS in 101 in TABLES in “Supplementary material”).
					
Location: 6°44.163’N, 91°56.061’W					
Water depth (m): 3634.7; 3645.4 mbrf					
Sediment thickness (m): 250					
Interval in Hole 1256C drilled during Leg 206: 338.5 mbsf, 88.5 msb					
Casing in Hole 1256D:					
Height of reentry cone: 2.4 m					
Internal diameter of reentry cone: 3.5 m (11 ft, 5 inches)					
20 inch casing string (m): 95.12					
16 inch casing string (m) 269					
Interval in Hole 1256D drilled during					
Leg 206: 752 mbsf, 502 msb; basement advance (m): 502					
Expedition 309: 1255.1 mbsf, 1005.1 msb; basement advance (m): 503					
Expedition 312: 1507.1 mbsf, 1257.1 msb; basement advance (m): 252					
Expedition 335: 1521.6 mbsf, 1271.6 msb; basement advance (m): 14.5					
					
Major lithologic zone	Sublithology	Top of lithology	Top igneous unit	Depth (mbsf)	Criteria
					
Lavas	Lava pond	206-1256D-2R-1, 0 cm	1256D-1
(1256C-1 through 1256C-18)	~250	Massive ponded lava including overlying sheet flows.
	Inflated flows	206-1256D-13R-1, 0 cm	1256D-2	350.3	Massive, sheet, and pillowed flows with rare inflation features.
	Sheet and massive flows	206-1256D-43R-1, 0 cm	1256D-16	533.9	Sheet flows with subordinate massive flows.
Transition zone		309-1256D-117R-1, 85 cm	1256D-40	1004.2	Sheet flows with breccia, rare dikes, and alteration at (sub)greenschist facies conditions.
Sheeted dike complex	Upper dikes	309-1256D-129R-1, 0 cm	1256D-44A	1060.9	Massive basalt, common subvertical intrusive contacts. Elevated P-wave velocity and thermal conductivity.
	Granoblastic dikes	312-1256D-192R-1, 0 cm	1256D-78	1348.3	Granoblastic texture; equant grains; secondary clinopyroxene, orthopyroxene, plagioclase, hornblende, magnetite, and ilmenite.
Plutonic section	Gabbro 1	312-1256D-213R-1, 52 cm (Piece 13)	1256D-81	1406.62	Medium-grained, generally orthopyroxene-bearing gabbroic rocks intrude overlying dikes: olivine gabbro, gabbro, and (disseminated) oxide gabbro, intruded by oxide gabbro to oxide quartz diorite.
	Dike Screen 1	312-1256D-225R-1, 0 cm (Piece 1)	1256D-90	1458.9	Fine-grained to cryptocrystalline basalt dikes. Highly altered; granoblastic texture; secondary clinopyroxene, orthopyroxene, plagioclase, magnetite, ilmenite, and hornblende.
	Gabbro 2	312-1256D-230R-1, 15 cm (Piece 5)	1256D-91	1483.1	Plutonic rock intrudes dike screen; medium-grained disseminated oxide gabbronorite with subordinate oxide gabbro, intruded by oxide gabbro, (oxide) diorite, and oxide quartz diorite veins; all highly altered; stoped basalt.
	Dike Screen 2	312-1256D-232R-2, 98 cm (Piece 9)	1256D-94	1494.9	Fine-grained granoblastic basalt (Unit 1256D-94) may have igneous or metamorphic origin. Unrecrystallized greenschist-facies late dike (Unit 1256D-95) at 1502.6 mbsf. Strongly to completely recrystallized granoblastic basalts containing minor oxide diorite patches; subordinate quartz diorite and tonalite (Unit 1256D-96). Also includes granoblastic basalts intruded by oxide gabbro to tonalite patches, veins, and dikelets and with minor (<3%) gabbroic rocks, from the “junkyards” at ~1500–1521.6 mbsf.