"169-1037B-57R-1, Piece 8b (44-48 cm)"					
Thin section: #74					
"ROCK NAME: Fine-grained, plagioclase-olivine-clinopyroxene-phyric basalt"					
GRAIN SIZE: Microcrystalline to fine-grained (seriate).					
TEXTURE: Variolitic to subophitic.					
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PRIMARY	PERCENT 	PERCENT	SIZE		
MINERALOGY	PRESENT	ORIGINAL	(mm)	MORPHOLOGY	COMMENTS
PHENOCRYSTS					
Plagioclase	25	25	0.5-2	"Laths, acicular."	"Generally fresh, common zoning, "
					inclusions of mesostasis. 
Olivine	1	7	0.2-2	Euhedral..	"Completely altered(?) to talc,"
					"stilpnomelane(?), and rims of magnetite."
Clinopyroxene	1	3	0.4-1.5	Stubby or ÒophitesÓ.	Partly altered to amphibole.
GROUNDMASS					
Plagioclase	38	38	0.04-0.5	"Acicular, prismatic."	"Fresh, minor alteration along cracks."
Clinopyroxene	10	21-Oct	0.02-0.4	Ophitic.	"Partly altered to amphibole, talc,"
					"Fe(O,OH)x."
Magnetite	4	3	0.01-0.03	"Ragged granular, "	
				acicular.	
Mesostasis	21-Oct	21-Oct			"Partly altered to amphibole, talc,"
					"Fe(O,OH)x."

SECONDARY		REPLACING/			
MINERALOGY	PERCENT	FILLING			COMMENTS
Actinolite/Mg-					
hornblende	20-Oct	"Mesostatis, clinopyroxene."		"Intergrown, felted mats."	
Talc	5	Olivine.			Inner rims of olivine.
Stilpnomelane(?)	2	Olivine.			Inner cores of replaced olivine.
Magnetite	1	Olivine.			Opaque rims around replaced olivine.

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"COMMENTS: Identification of stilpnomelane is tentative. A green, brownish-yellow pleochroic mineral is commonly present at the cores of many replaced"							
"olivine(?) phenocrysts. The out rims are surrounded by talc and armoring of secondary magnetite. This mineral is uniaxial negative, with high second order"							
birefringence. The presence of 2 orthogonal cleavages supports the identification as stilpnomelane as opposed to biotite. Presence of high temperature K-							
"bearing phases is unusual in ocean floor rocks, in which K is normally quantitatively stripped at elevated temperatures (>200¡C). This may indicate a"							
"secondary event of hydrothermal activity that overprints seafloor (low-temperature) weathering, resulting in K-enriched basalts."							


"169-1037B-58R-1, Piece 6 (61-64 cm)"							
Thin section: #75							
ROCK NAME: Fine-grained basalt.							
GRAIN SIZE: Microcrystalline to fine-grained (seriate).							
TEXTURE: Intersertal to subophitic.							
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PRIMARY		PERCENT 	PERCENT	SIZE			
MINERALOGY		PRESENT	ORIGINAL	(mm)		MORPHOLOGY	COMMENTS
PHENOCRYSTS							
Plagioclase		10	10	2-Jan		"Laths, acicular."	"Generally fresh, some corroded margins."		
Olivine (?)		Tr	5	0.5-1		Prismatic.		"Trace of remnant grains, altered to green"	
									"mica, amphibole, talc, agetite, amorphous"
				 					"silica(?), calcite."
GROUNDMASS									
Plagioclase		40	40	0.04-1		"Laths, acicular."	"Fresh, minor clay alteration along cracks."		
Clinopyroxene		5	15	0.04-1		"Ophitic, subhedral."	Mostly altered to amphibole.		
Magnetite			7	5	0.01-0.1		"Granular, acicular."	Commonly in orthogonal or 120¡ criss-	
									cross pattern.
Mesostasis		25-Oct	25					"Amphibole, secondary magnetite."	

SECONDARY			REPLACING/						
MINERALOGY		PERCENT	FILLING					COMMENTS	
Actinolitic hornblende		Oct-35	"Clinopyroxene, mesostasis."						
Iron-oxyhydroxides/									
Clay minerals		10-May	"With amphibole, after olivine and groundmass."						
Talc			Trace	Olivine.						
Magnetite			7	"Mesostasis, olivine."						
Calcite			Trace	Olivine.						
Amorphous silica		Trace	Olivine.							

VESICLES/			SIZE							
CAVITIES		PERCENT		(mm)	FILLING		SHAPE			COMMENTS
Vesicles			1		1	Amphibole. 	Rounded.			Filled with actinolitic hornblende.

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COMMENTS: Thin section crosscut by two thin (<0.5 mm) actinolitic-hornblende veinlets with a 1-2 mm envelope of amphibole- and iron-oxyhydroxide-rich										
"groundmass, altered clinopyroxene and olivine phenocrysts. "										

N.B. - Each side of the chilled margin is described separately.										

"169-1037B-58R-2, Piece 3 (21-24 cm), first half"										
Thin section: #76									
ROCK NAME: Chilled margin between cryptocrystalline plagioclase-olivine basalt and microcrystalline									
to fine-grained plagioclase-olivine-phyric basalt									

ROCK NAME: Plagioclase-olivine-phyric basalt									
GRAIN SIZE: Cryptocrystalline-glassy.									
"TEXTURE: Porphyritic, quenched."									
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PRIMARY		PERCENT 	PERCENT	SIZE					
MINERALOGY		PRESENT	ORIGINAL	(mm)		MORPHOLOGY	COMMENTS		

PHENOCRYSTS									
Plagioclase		20	20		0.1-2		Laths.		
Olivine			4	5		0.5-1		Sub- to euhedral.	"Rims of Fe(O,OH)x and clays."
GROUNDMASS									
Mesostasis		73					Quenched to variolitic.	"Varioles along chill, incipient plagioclase"	
										and clinopyroxene.

SECONDARY			REPLACING/							
MINERALOGY		PERCENT	FILLING					COMMENTS		
Amphibole		3	"Olivine, vesicles."				"With Fe(O,OH)x."			

VESICLES/			SIZE							
CAVITIES		PERCENT		(mm)	FILLING		SHAPE		COMMENTS	
Vesicles			2		0.2-1	Amphibole.	Rounded.		More common towards chill.	
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COMMENTS: Varioles along chilled margin. A number of very fine (0.1 mm) amphibole veins along margin and into the quench zone. Quenched zone										
approximately 2 mm wide.										


"169-1037B-58R-2, Piece 3 (21-24 cm), second half"										
Thin section: #76										
ROCK NAME: Plagioclase-olivine-phyric basalt.									
GRAIN SIZE: Microcrystalline to fine-grained 									
TEXTURE: Intersertal.									
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PRIMARY		PERCENT 	PERCENT	SIZE					
MINERALOGY		PRESENT	ORIGINAL	(mm)		MORPHOLOGY	COMMENTS		

PHENOCRYSTS									
Plagioclase		15	15	0.4-2		Prismatic.		Glomerocrystic.	
Olivine			1	3	0.2-0.5		Subhedral.		With plagioclase. Mostly rimmed and
									corroded by amphibole.
GROUNDMASS									
Plagioclase		25	25	0.04-0.4					
Clinopyroxene		25-Oct	25	0.04-0.5		"Stubby, ophitic."			
Magnetite			5	5	0.01-0.08		Granular or acicular.		
Mesostasis		25-Oct	25			Irregular patches.	Irregular patches (>1 mm).		

SECONDARY			REPLACING/						
MINERALOGY		PERCENT	FILLING					COMMENTS	
Actinolite			15-30	"Mesostasis, olivine, clinopyroxene, veins, vesicles."	Probably with associated clay minerals and				
									"Fe(O,OH)x."
Calcite			Trace	Olivine cores.					

VESICLES/			SIZE						
CAVITIES		PERCENT	(mm)	FILLING		SHAPE		COMMENTS	
Vesicles			2	0.5-1	Actinolite		Subrounded.		

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COMMENTS: A number of 0.5 mm amphibole veins. This side of the chilled margin is also finer grained towards the chill and apparently quenched. Quenched									
zone 1-2 mm wide. Some merging of magmas?									

"169-1037B-58R-2, Piece 9b (65-70 cm)"									
Thin section: #77										
ROCK NAME: Plagioclase-olivine-phyric basalt.										
GRAIN SIZE: Cryptocrystalline-glassy.										
TEXTURE: Porphyritic.										
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PRIMARY		PERCENT 	PERCENT	SIZE						
MINERALOGY		PRESENT	ORIGINAL	(mm)		MORPHOLOGY	COMMENTS			

PHENOCRYSTS										
Plagioclase		15	15		0.1-2.5		Acicular laths.	"Scattered throughout groundmass,"		
										commonly glomerocrystic.
Olivine			2	4		0.5-1		"Stubby, prismatic."	Mostly fresh; commonly with red ragged	
										"alteration rims (Clays + Fe(O,OH)x(?))."
GROUNDMASS										
Mesostasis		76	76				"Glassy, varioles."	Glassy to cryptocrystalline. Incipient		
										crystals of plagioclase.
Magnetite			5	5		0.01-0.03		Granular.		

SECONDARY			REPLACING/							
MINERALOGY		PERCENT	FILLING					COMMENTS		
Actinolite		} 	20-Jun	"All minerals are after olivine,"						
Clays		}		replacing mesostasis and filling						
Talc		}		"veins, irregular patches, and vesicles."						
"Fe(O,OH)x"	}									


VESICLES/			SIZE							
CAVITIES		PERCENT		(mm)	FILLING		SHAPE			COMMENTS
Vesicles			2		0.5-1	Actinolite.		Subrounded to irregular.		
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"COMMENTS:  Thin (0.1-0.5 mm) actinolite vein cuts across section; margin of discontinuous magnetite grains. Vein pinches and swells along length, necking"										
at sinistral jogs and dilating on length sections in between.										


"169-1037B-60R-1, Piece 11c (118-125 cm)"										
Thin section: #78										
ROCK NAME: Fine-grained basalt (N.B. desiccating rock).										
GRAIN SIZE: Fine-grained.										
TEXTURE: Intersertal to subophitic.										
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PRIMARY		PERCENT 	PERCENT	SIZE						
MINERALOGY		PRESENT	ORIGINAL	(mm)		MORPHOLOGY	COMMENTS			
GROUNDMASS										
Plagioclase		40	40		0.04-3		Laths.		"Plagioclase framework, commonly"	
										radiating.
Clinopyroxene		20-33	33		0.05-2		"Subophitic, prismatic."	Generally fresh or altered to actinolite.		
Olivine (?)		0	2		0.2-0.8		Prismatic.		"Completely altered to clays, micas, talc,"	
										"amphibole, and Fe(O,OH)x."
Magnetite			5	5		0.01-0.05		Granular.		
Mesostasis		0	10						Irregular interstitial patches altered to clay	
										minerals and actinolite.

SECONDARY			REPLACING/							
MINERALOGY		PERCENT	FILLING					COMMENTS		
Actinolite		}	All Minerals	"After groundmass,"						
Clays		}	 15-30	filling vesicles and replacing						
"Fe(O,OH)x"	}		olivine and clinopyroxene.							
Talc		}								

VESICLES/			SIZE							
CAVITIES		PERCENT		(mm)	FILLING		SHAPE			COMMENTS
Vesicles			10		0.5-3	Fibrous 		Subrounded to irregular		
						amphibole.				
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"COMMENTS: This sample is from the zone of unusual desiccation, where on drying coherent pieces of basalt collapsed into flaky powder. The reason for the"										
"decay is still not obvious from this section, though large portions of the slice are completely plucked out. Presumably plucking is most intense in regions that"										
were most altered. XRD confirms presence of smectite in rock.										

"169-1037B-61R-1, Piece 2 (104-112 cm)"										
Thin section: #79										
ROCK NAME: Plagioclase-clinopyroxene-olivine basalt										
GRAIN SIZE: Fine- to medium-grained.										
"TEXTURE: Intersertal to ophitic, diabasic."										
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PRIMARY		PERCENT 	PERCENT	SIZE						
MINERALOGY		PRESENT	ORIGINAL	(mm)		MORPHOLOGY	COMMENTS			
Plagioclase		47	48		0.2-3		"Laths, prismatic."	"Rare, anhedral plagioclase co-crystallized"		
										with clinopyroxene.
Clinopyroxene		25-30	37		0.2-3		"Subhedral, ophitic."	Generally fresh.		
Olivine			1	5		0.2-1		Prismatic.		"Mostly altered, some relict cores."
Magnetite			5	5		0.05-1		"Subhedral, prismatic."
Mesostasis		0	5					

SECONDARY			REPLACING/					
MINERALOGY		PERCENT	FILLING					COMMENTS
Clay minerals								
" + Fe(O,OH)x"	} 	15-May	"Mesostasis, olivine, some clinopyroxene."					
Talc		}						

VESICLES/			SIZE					
CAVITIES		PERCENT	(mm)	FILLING		SHAPE		COMMENTS
Vesicles			1					

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------								
"COMMENTS: Generally a very fresh rock. Some alteration of groundmass, olivines, and clinopyroxenes. "								


"169-1037B-62R-1, Piece 5b (126-128 cm)"										
Thin section: #80										
ROCK NAME: Plagioclase-clinopyroxene diabase										
GRAIN SIZE: Medium-grained.										
TEXTURE: Ophitic.										
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PRIMARY		PERCENT 	PERCENT	SIZE						
MINERALOGY		PRESENT	ORIGINAL	(mm)		MORPHOLOGY	COMMENTS			
Plagioclase		47	48		0.5-4		Laths.			
Clinopyroxene		15-25	37		0.2-3		Ophitic.			
Olivine			0	3		0.2-0.5		Prismatic.		Altered to green-brown pleochroic mica.
Magnetite			5	5		0.05-3		"Granular, needles."		
Mesostasis		0	7						Altered to secondary minerals.	

SECONDARY			REPLACING/							
MINERALOGY		PERCENT	FILLING					COMMENTS
Clay minerals	} 	20-30	"Olivine(?), clinopyroxene (partial), mesostasis."					
"  +/-Fe(O,OH)x"	}							
Actinolite	}							
Green mica	}							
Talc		}						

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"169-1037B-62R-3, Piece 6 (82-86 cm)"								
Thin section: #81								
ROCK NAME: Plagioclase-clinopyroxene-olivine basalt								
GRAIN SIZE: Medium- to coarse-grained.								
TEXTURE: Holocrystalline; microgabbroic.								
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PRIMARY		PERCENT 	PERCENT	SIZE						
MINERALOGY		PRESENT	ORIGINAL	(mm)		MORPHOLOGY	COMMENTS			
Plagioclase		40	41		0.5-5		Laths.			
Clinopyroxene		45	47		0.5-6		Large subhedral patches.			
Olivine			2	5		0.2-1		Prismatic.		Partly to completely altered to secondary
										minerals.
Magnetite			4	5		0.2-1		Euhedral.		"Some Fe(O,OH)x."
Mesostasis		0	2				Interstitial patches.	Completely altered to secondary minerals.		

SECONDARY			REPLACING/							
MINERALOGY		PERCENT	FILLING					COMMENTS		
Clay minerals	}	20-Oct								
"  +Fe(O,OH)x"	}									
Talc		}								

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------										
COMMENTS:  Coarse-grained basalt. Beyond ophitic in texture. Clinopyroxene now makes up the structure of the rock with plagioclase laths isolated within
large clinopyroxene grains. A Òmicrogabbro.Ó