THIN SECTION:	"U1301B-18R-4, 17-19 cm (Piece 1a)"				TS #	33	Unit:6	"OBSERVER: MS, RC"
ROCK NAME: 	Moderately olivine-clinopyroxene-plagioclase phyric basalt							
WHERE SAMPLED:	Vein							
GRAIN SIZE:	Crypto to microcrystalline							
TEXTURE:	"Intersertal to intergranular, glomeroporphyritic"							
PRIMARY	PERCENT 	PERCENT	SIZE (mm)			APPROX.		
MINERALOGY	PRESENT 	ORIGINAL	min.	max.	av.	COMP.	MORPHOLOGY	COMMENTS
PHENOCRYSTS								
Plagioclase	5	5	1.1	3.8	1.8		Euhedral to subhedral	"Stubby laths, and in mono- and poly-mineralic glomeroporphyric clots. Pale green or brown glass inclusions in the cores of some crystals."
Clinopyroxene	2	2	0.5	1.2	0.8		Euhedral to anhedral	"Occurs singly, but more frequently in glomeroporphyritic clots or associated with plagioclase laths."
Olivine	0	1	0.8	1.2	1		Euhedral to subhedral	Completely replaced by saponite.


GROUNDMASS								
Plagioclase	55	55		<1.1			Euhedral to subhedral	Laths.
Clinopyroxene	20	20		<0.5			Euhedral to anhedral	Occurs singly or attached to/intergrown with plagioclase.
Olivine	0	12		<0.8			Euhedral to subhedral	Completely replaced by saponite.
Opaque minerals	5	5						

SECONDARY			SIZE (mm)					
MINERALOGY	PERCENT		min.	max.	av.		REPLACING / FILLING	COMMENTS
Saponite  	12						"Olivine, mesostasis, vein, vesicles"	Brown to brown-gray color.
Carbonate	1						Vein	


VESICLES/			SIZE (mm)					
CAVITIES	PERCENT	 LOCATION	min.	max.	av.		FILLING / MORPHOLOGY	COMMENTS
Vesicles	Tr	Even	0.1	0.3	0.2		Saponite	



COMMENTS : 	"Veins: 0.05-0.2 mm, anastamosing saponite and carbonate veins. These microveins cut through crystals, or 'step' around them. Carbonate does not occur along the entire length of the vein. Carbonate forms a fibrous central vein fill suggesting it formed after the saponite."