"168-1026B-1R-01 (piece 7, 29-33cm)" ROCK NAME: Aphyric basalt GRAIN SIZE: Aphanitic TEXTURE: Hypocrystalline; sheaf-spherulitic +/- plumose; microglomeroporphyritic; vesicular. PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Plagioclase 0.4 0.4 <=0.5 (Ave 0.3) Euhedral Laths and stubby crystals; minor simple zoning. GROUNDMASS Plagioclase 8.8 8.8 Ave 0.1 Euhedral laths Microlites + microlaths form euhedral and quench crystals (swallowtail; hollow crystals etc.). Occur singly and within glomeroporphyritic clots. Olivine 0 2.4 <=0.2 (Ave 0.1) Euhedral-subhedral Completely replaced by brown clay (saponite). Clinopyroxene 3.2 3.2 <=0.06 (Ave 0.03) Subhedral "Occurs as single grains throughout the groundmass, and as granular crystals in glomeroporphyritic clots with plagioclase." Opaques 0.02-0.1 Subhedral-anhedral "Discrete 0.02-0.1mm grains of pyrite(?) only occur within the ""fresh"" interior of the rock; very fine (<0.01mm) opaques occur throughout the whole section. Point count together with mesostasis" Mesostasis 78 83.4 "Gray-brown cryptocrystalline to granular material, with feathery plumes and sheafs separated by fine, disseminated opaques." SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Saponite 4 Vesicles; mesostasis; olivine "Granular, tan brown. Only present within the inner core of the section (i.e. not in the alteration halo)." Celadonite 3.6 Vesicles; mesostasis; olivine "Granular, bright green. Occurs within the inner 4-5mm of the alteration halo only." Iddingsite 1.3 Vesicles; mesostasis; olivine Dark brown to orange; massive. Forms the outer 1-1.5mm band of the alteration halo. Pyrrhotite 0.7 "Vesicles, mesostasis" "Sparse anhedral to subhedral grains (0.1-0.2mm) often associated with saponite; absent in the oxidation halo. Each grain is a mosaic of several smaller grains, visible only in polarized reflected light." Hematite Tr Vesicles Deep red; reflective. Occurs in the outer c.1mm layer of the alteration halo. VESICLES/ CAVITIES PERCENT LOCATION SIZE (mm) FILLING SHAPE COMMENTS: Gas vesicles Even 0.05-0.1 Clay Round "Completely filled by iddingsite, hematite, celadonite or saponite, depending on the location within the section; some vesicles are only partially filled by saponite." Segregation vesicles Even <=0.2 Mesostasis +/- clay Round "Either completely filled by mesostasis, or with a partial fill of mesostasis followed by clay." COMMENTS: "The section has a very pronounced alteration halo around the margin, consisting of a brown-green 5-7mm band followed by a c.2mm light blue-gray band." "Within the halo, there is a clear zonation of the alteration clays: 1) a 1-1.6mm band of iddingsite +/- hematite, filling vesicles and replacing olivine +/- mesostasis; " 2) a <=0.5mm iddingsite + celadonite mixed zone; some vesicles have a 0.005mm celadonite rim preceding the iddingsite +/- celadonite infill; 3) a 4-5mm "celadonite only zone, filling vesicles +/- replacing mesostasis and olivine; 4) interior of the rock (beyond the alteration halo) with saponite only. Sub-anhedral " grains of pyrrhotite are present only within this inner zone (i.e. they are absent in the alteration halo). Section contains microglomeroporphyritic clots (0.4-1.6mm) of plagioclase + pyroxene + opaques. "168-1026B-04R-01 (piece 7, 36-44 cm)" ROCK NAME: Aphyric basalt GRAIN SIZE: Cryptocrystalline "TEXTURE: Varitextured; glassy to variolitic, subvariolitic, sheaf spherulitic." PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Plagioclase 0.6 0.6 0.5-0.7 Euhedral laths Present as solitary crystals and within monomineralic glomerocrysts; oscillatory zoning common. GROUNDMASS Plagioclase 12.4 12.4 <=0.4 Euhedral laths; skeletal "Present as laths, microlites and quench crystals." Olivine + pyroxene 0.4 4 0.05-0.2 Anhedral-subhedral Completely to partially replaced by secondary minerals; a few fresh very fined grained crystals are still present. Mesostasis 64.6 72 Texture varies from variolitic to subvariolitic to sheaf spherulitic. Glass 3.2 5.8 "Glass fragments with concentric color zonation from rim to core changing from brown, to light brown, to dark brown. Only the core is fresh (completely extinct in xpl)." Pyrite Tr Tr <=0.005 Granular "Present in the glass rim, and as euhedral grains within very small vesicles within the glass." SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Celadonite 4 Vesicles; mafic phases Bright green fibrous to cryptocrystalline aggregates infilling vesicles and partially to completely replacing groundmass mafic crystals. Saponite 6.8 Vesicles; mafic phases; veins Pale brown fibrous to cryptocrystalline aggregates infilling vesicles and partially to completely replacing groundmass mafic crystals. Iddingsite 5.4 Vesicles; mafic phases Bright orange-brown-red partially to completely infilling veins and replacing mafic phases. Altered glass (palagonite?) 2.6 Quenched glass From orange to pale brown. Zeolites? Tr Veins "Colorless, low relief, possibly 2 types: 1) Fibrous radiate, birefringence white to gray; 2) Granular, forms within veins, very low birefringence." Pyrite Tr Veins; vesicles "<=0.01mm; sparse, occurs within saponite within the rims of veins." Hematite? Tr Veins VESICLES/ CAVITIES PERCENT LOCATION SIZE (mm) FILLING SHAPE COMMENTS: Gas vesicles 1.6 Even 0.05-0.1 Clay; iddingsite Round See comments below. COMMENTS: "The glassy margin has a highly fractured, hyaloclastic texture. Single fragments of glass exhibit decreasing concentric alteration bands from their rim " to their cores. Alteration haloes exhibit a clear concentric zonation of secondary mineral phases from iddingsite to celadonite to saponite; this banding also "occurs in the mesostasis and vesicle infills. Throughout the section, there is a network of veins, with individual veins 0.3-0.4mm wide, infilled by a mixture" "of saponite and minor amount of zeolite. One deep-red vein (<=0.1mm wide) is infilled by iddingsite +/- hematite (deep red purple in ppl, light gray reflectance)." "168-1026B-05R-01 (piece 1, 46-49cm)" ROCK NAME: Moderately phyric plagioclase-olivine-pyroxene basalt GRAIN SIZE: Aphanitic TEXTURE: Varitextured; intersertal; sheaf spherulitic; glomerophyric; vesicular. PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Olivine Tr 0.4 0.5-0.7 Euhedral-subhedral "Present as pseudomorphs, completely replaced by celadonite +/- saponite +/- iddingsite." Plagioclase 3 3 0.5-1.1 Euhedral laths Commonly zoned; forms glomeroporphyritic clusters with interstitial groundmass material. Clinopyroxene 0.2 0.2 0.5-0.8 Subhedral-anhedral Present in glomeroporphyritic clusters with plagioclase. GROUNDMASS Plagioclase 4 4 <=0.3 Subhedral "Present as laths, microlites and skeletal crystals." Olivine 0 1.5 <=0.5 Euhedral to subhedral Completely replaced by celadonite +/- saponite +/- iddingsite. Clinopyroxene 3 3 <=0.2 Anhedral "Skeletal to granular, closely associated with interstitial plagioclase grains." Opaques 0.4 0.4 <=0.05 Anhedral Microcrystalline to cryptocrystalline grains present within the interstitial mesostasis +/- forming skeletal chains. Mesostasis 86.5 86.5 SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Saponite 2.1 Olivine; vesicles "Yellow to pale brown; forms a thin rim within vesicles, as well as pseudomorphing olivine +/- pyroxene." Celadonite 0.6 Olivine; vesicles; mesostasis Bright green; concentrated in the alteration halo. Pyrrhotite 0.2 0.2 <=0.05 Anhedral Disseminated individual grains where celadonite predominates or with saponite along the rim of gas vesicles. Absent in external alteration halo of the rock. Iddingsite Tr Vesicles "Completely fills some vesicles, whilst being associated with celadonite in others." VESICLES/ CAVITIES PERCENT LOCATION SIZE (mm) FILLING SHAPE COMMENTS: Gas vesicles 2.4 COMMENTS: "Saponite occurs throughout the section with the exception of the alteration halo, where celadonite and iddingsite are prevalent. There is an unusual " abundance of sulfide grains (pyrrhotite) in the section (point count reveals 0.2%). These grains are absent in the alteration halo. "168-1026C-16R-01 (piece 10, 40-45cm)" ROCK NAME: Sparsely phyric plagioclase-pyroxene basalt GRAIN SIZE: Aphanitic TEXTURE: Sheaf-spherulitic; glomeroporphyritic; vesicular PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Plagioclase 1.4 1.4 0.8-1.5 (Ave 0.8) Euhedral-subhedral "Occurs singly, but is more common in monomineralic, bimineralic and polymineralic glomeroporphyritic clots with pyroxene +/- olivine." Clinopyroxene 0.2 0.2 0.6-0.8 (Ave 0.8) Subhedral-euhedral Subophitic to ophitic arrangement with plagioclase in bimineralic glomeroporphyritic clots. GROUNDMASS Plagioclase 11.6 11.6 0.1-0.5 (Ave 0.3) Subhedral "Microlaths, microlites and quench crystals. Occurs in monomineralic, bimineralic and polymineralic glomeroporphyritic clots." Olivine 0 1.8 0.1-0.3 (Ave 0.3) Euhedral "Occurs in polymineralic glomeroporphyritic clots, as well as singly. All olivine is replaced by saponite +/- iddingsite." Clinopyroxene 6.4 6.4 0.05-0.3 Anhedral-euhedral Anhedral grains are intergrown with plagioclase +/- olivine in glomeroporphyritic clots. Smaller solitary euhedral-subhedral crystals (0.05-0.1mm) occur in the mesostasis. Opaques Tr Tr Ç0.01 Granular Minor opaque oxides and sulfides occur in the mesostasis. Mesostasis 71.1 77 Sheaf-spherulitic texture; cryptocrystalline with microcrysts of pyroxene + opaque oxides + opaque sulfides. SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Saponite 4.2 Vesicles; olivine Forms >0.02mm fibrous linings in vesicles inside of the alteration halo. Also forms <0.01mm granular bands followed by a fibrous filling in some vesicles. Celadonite 4 Vesicles; olivine Fibrous; lines some vesicles and fills others. Iddingsite 1.1 Vein Massive texture. Hematite Tr Vein; olivine; vesicles "Limited to the alteration halo, associated with iddingsite and celadonite. The grains are irregular in shape and <=15mm. Hematite fills some vesicles and forms a band between celadonite bands in others." Calcite Tr Vein; vesicles Sparry crystals. VESICLES/ CAVITIES PERCENT LOCATION SIZE (mm) FILLING SHAPE COMMENTS: Gas vesicles 1.6 Even 0.05-0.4 Clay Round Partially to completely infilled by secondary clays and opaque oxides. Segregation vesicles Tr Even 0.1-0.15 Mesostasis Round Infilled by mesostasis + opaque rods. COMMENTS: "Vein at the rock edge has a 0.1-0.2mm layer of iddingsite + isotropic opaque mineral, followed by a ~0.07mm layer of anhedral, granular calcite (uniaxial). " "This is followed by an incomplete zone of rounded iddingsite ""clasts"" set within a clay(?) matrix. The alteration halo is 2-5mm wide, containing celadonite" "band followed by iddingsite filling vesicles, or celadonite followed by saponite." "Glomeroporphyritic clots vary in form; some exhibit a rounded external margin whilst others have mesostasis included between the crystals, frequently" "surrounded by a fine, lighter band of mesostasis. These may represent rip-up clots, rather than clots formed in the circulating magmatic melt." "168-1026C-17R-01 (piece 8, 31-38cm)" ROCK NAME: Aphyric basalt GRAIN SIZE: Aphanitic TEXTURE: Hypocrystalline; sheaf-spherulitic; glomeroporphyritic; vesicular PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Plagioclase 0.8 0.8 0.4-0.9 (Ave 0.4) Euhedral-subhedral Blocky and elongate laths (one lath is 2mm long) occur singly and within monomineralic (1-2mm long) and bimineralic glomeroporphyritic clots. Simple to faint oscillatory zoning. Clinopyroxene 0.2 0.2 0.5-0.7 (Ave 0.7) Subhedral-euhedral; poikilitic Subophitic to ophitic arrangement with plagioclase in bimineralic glomeroporphyritic clots. GROUNDMASS Plagioclase 14.6 14.6 0.1-0.6 (Ave 0.35) Euhedral-subhedral "Quench crystals, microlaths and microlites occurring singly and within glomeroporphyritic clots; some stellate clusters." Olivine 0 1.6 0.1-0.2 Euhedral-subhedral Occurs singly or attached to plagioclase; totally replaced by saponite. Clinopyroxene 6 6 0.05-0.2 Euhedral-anhedral Occurs singly or attached to/intergrown with plagioclase. Opaques Tr Tr <=0.02 Granular-skeletal Intergranular in the mesostasis. Mesostasis 61 75.2 Cryptocrystalline; brown-gray color with a massive to sheaf-spherulitic texture. SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Saponite 8.6 Vesicles; olivine; mesostasis Granular; olive-brown. Celadonite 7.2 Vesicles; mesostasis Fibrous in vesicles; granular to fibrous in mesostasis. Iddingsite 1.6 Vein; vesicles Granular to massive; hematite is associated with iddingsite. Pyrite/pyrrhotite Tr Vein; vesicles "Interstitial at leading edge of alteration halo, <=0.01mm grains." VESICLES/ CAVITIES PERCENT LOCATION SIZE (mm) FILLING SHAPE COMMENTS: Gas vesicles 1.6 Even 0.1-0.25 Clay Round "Lined to filled by fibrous +/- granular saponite in the rock inside of the halo. Within the alteration halo, the vesicles are filled with iddingsite +/- hematite; fibrous celadonite + iddingsite layers; fibrous celadonite." COMMENTS: "Alteration halo (<=8mm) shows bands of celadonite, iddingsite, then +/- saponite in successive linings and fillings of the vesicles. Iddingsite dominates the" "fractured side of the halo, whereas celadonite dominates the rock core side. The leading edge of the halo is marked by a 0.2mm +/- band of concentrated " interstitial pyrrhotite/pyrite. "When viewed in PPL, a number of glomeroporphyritic clots exhibit pseudo-crystal outlines with cross-cutting plagioclase laths. The pseudocrystal is infilled " "by granular pyroxene and may represent the disequilibrium break-down of olivine or pyroxene, and replacement by fine grained pyroxene."