"168-1024B-18X-CC (Piece 3, 009-027 cm)" ROCK NAME: Aphyric plagioclase-clinopyroxene basalt GRAIN SIZE: Aphanitic: cryptocrystalline-microcrystalline TEXTURE: Variolitic-subvariolitic; holohyaline-hypocrystalline PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Plagioclase 0.1 0.1 0.4-1.6 Euhedral laths "Present as individual crystals; simple to oscillatory zoning in the cores. One anhedral xenocryst present, with glass inclusions (c.8 microns) in the core." Clinopyroxene Tr Tr 0.25 Euhedral Two crystals found; faint oscillatory zoning. GROUNDMASS Plagioclase 4.6 4.6 0.05-0.15 Microlitic laths "Swallowtail, acicular needles." Clinopyroxene 3.3 3.3 <=0.2 Euhedral Mesostasis 86.3 86.3 "Changes from dark brown subvariolitic, to a orange-brown honeycomb to a yellow-brown honeycomb and finally to a light gray-brown branching texture with increasing distance from the chilled margin." Glass 3.5 3.5 Clear <=0.6mm-thick glass margin containing discrete varioles centered around plagioclase and pyroxene microlites Pyrite Tr Tr 0 Granular In mesostasis. SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Celadonite Tr Vesicles and microfractures "Forms an fine layer within some vesicles, and partially fills some microfractures." Saponite 0.4 Vesicles and microfractures "Lines the microfractures cross cutting the section and partially fills some vesicles, after celadonite and/or iddingsite." Iddingsite Tr Vesicles Forms a layer of fine granules after celadonite in some vesicles. Pyrite Tr Vesicles Forms drusy euhedral grains partially lining some vesicles. VESICLES/ CAVITIES PERCENT DISTRIBUTION SIZE (mm) FILLING SHAPE COMMENTS: Vesicles 1.8 Even 0.05-0.1 Partial to complete Round to irregular. See comments above. COMMENTS: Plagioclase microlites and varioles exhibit a preferred alignment parallel to the chilled margin. Secondary alteration minerals are restricted to a 1-2mm band on either side of the microfractures cross cutting the rock. "168-1024B-18X-CC (Piece 12, 009-027 cm)" ROCK NAME: Aphyric plagioclase-pyroxene basalt GRAIN SIZE: Aphanitic: microcrystalline to cryptocrystalline TEXTURE: Variolitic to subvariolitic; hypocrystalline PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Plagioclase Tr Tr 0.1-0.5 Sub- to euhedral laths Individual crystals and as monomineralic and bimineralic glomeroporphyritic cluster with clinopyroxene; some glass inclusions present. Simple and oscillatory zoning in some crystals. Clinopyroxene Tr Tr 0.2-0.3 Subhedral-euhedral Present singly and in a bimineralic glomeroporphyritic clots with plag. GROUNDMASS Plagioclase 11.3 11.3 0.03-0.1 Microlitic laths "Skeletal, hollow and swallowtails." Olivine Tr Tr 0.05-0.1 Sub- to euhedral Clinopyroxene 7.6 7.6 <=0.05 Subhedral equant Often aggregated with plagioclase microlite Mesostasis 79 79 "Changes from dark brown subvariolitic, to a deep reddish brown plumose, to dark gray-brown plumose and finally to a light gray-brown branching texture with increasing distance from the chilled margin." Glass 0.7 0.7 "Clear <=2.5mm-thick glassy margin with minor amounts of plagioclase microlites, olivine +/- pyroxene microphenocrysts (acting as nuclei for varioles) and devitrified glass." Pyrite Tr Tr <=0.002 Granular In glass. Chalcopyrite Tr Tr <=0.02 Granular In mesostasis. SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Saponite Vesicles "Forms an inner lining in some vesicles, preceded by an earlier coating of celadonite." Celadonite Vesicles and fractures "Restricted to alteration halo, lines vesicles and forms irregular groundmass clots perhaps replacing olivine. In some vesicles, the lining may be followed by pale green celadonite, saponite or iddingsite." "Pyrite, pyrrhotite, chalcopyrite" Tr Groundmass and vesicles "A 400 micron diffuse band contains concentrated 1-5 micron granular sulfides (a few reach 70 microns). This band corresponds to the inner edge of the alteration halo. In one vesicle, two botryoidal masses of sulfide (15 microns wide) occur on the wall." VESICLES/ CAVITIES PERCENT DISTRIBUTION SIZE (mm) FILLING SHAPE COMMENTS: Vesicles 1.4 Even 0.05-0.1 Partial Round to oval "Clear or partially filled with saponite, celadonite, iddingsite +/- sulfide" COMMENTS: The crystallinity gradually increases towards the interior of the rock. A dark alteration halo extends 2-10mm into the rock from the glass margin. The shape of the halo is also influenced by the presence of small microfractures. "168-1024C-01R-01 (piece 1, 0-8 cm)" ROCK NAME: Aphyric basalt GRAIN SIZE: Aphanitic; cryptocrystalline TEXTURE: Variolitic to subvariolitic PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Olivine Plagioclase Tr Tr 0.5-1.2 Euhedral "Solitary crystals or within glomeroporphyritic clots. Some have an irregular outline, and are partially devitrified with glass inclusions in the core; the crystals are strongly zoned." Clinopyroxene Opaques GROUNDMASS Plagioclase 1.6 1.6 <=0.1 Euhedral "Laths and needles; microlites exhibit a subparallel orientation, parallel to the chilled margin. Microlite grain size increases with distance from the margin." Olivine Clinopyroxene 0.4 0.4 <=0.05 Granular Skeletal grains. Opaques Glass Tr Tr Fresh pale brown glass containing abundant varioles and plagioclase microlites. Mesostasis 96.2 98 Skeletal cryptocrystalline microcrysts set within a sheaf-spherulitic to plumose cryptocrystalline mass. SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Iddingsite 0.6 Vesicles; mesostasis "Red-brown; granular to massive; fills the vesicles. In some vesicles, iddingsite is associated with hematite." Saponite 0.2 Vesicles; mesostasis Tan color; granular to massive texture. Celadonite 1 Vesicles; mesostasis "Green; granular to fibrous, either forming bands at the rims or completely fills vesicles." Pyrrhotite Tr "Interstitial, granular (0.005-0.03mm) concentrated in a discontinuous band just beyond the leading edge (celadonitic) of the alteration halo." VESICLES/ CAVITIES PERCENT LOCATION SIZE (mm) FILLING SHAPE COMMENTS: Gas vesicles 0.8 Even <=0.05 Clay Round "Iddingsite, saponite and celadonite partially to completely fill the vesicles. The type of clay filling the vesicle depends on its location in the alteration halo." COMMENTS: "The section contains one small vein (~0.01mm wide) filled by red-orange iddingsite +/- saponite, cutting across the mesostasis as well as plagioclase phenocrysts." "The vein has a 1.5mm oxidation halo associated with it, on either side." "168-1024C-01R-01 (piece 2, 8-15 cm)" ROCK NAME: Aphyric basalt GRAIN SIZE: Aphanitic; microcrystalline to cryptocrystalline TEXTURE: Intersertal to intergranular. PRIMARY MINERALOGY PERCENT PRESENT PERCENT ORIGINAL SIZE (mm) COMPOSITION MORPHOLOGY COMMENTS PHENOCRYSTS Olivine Plagioclase Tr Tr 0.4-0.8 Euhedral Laths and stubby crystals; occur singly and within monomineralic glomeroporphyritic clots; minor simple zoning. Clinopyroxene Opaques GROUNDMASS Plagioclase 7.7 7.7 <=0.1 Euhedral-subhedral Microlaths and microlites form an intersertal framework. Olivine Tr Tr <=0.1 Euhedral Completely replaced by pale brown saponite. Clinopyroxene 10.3 10.3 0.02-0.05 Granular Grains are interstitial to plagioclase. Opaques Tr Tr <=0.005 Granular Disseminated throughout the mesostasis. Mesostasis 79.1 81.6 "Characterized by sheaf-spherulitic to plumose texture, interstitial to the plagioclase +/- pyroxene framework." SECONDARY MINERALOGY PERCENT REPLACING/ FILLING COMMENTS: Iddingsite 0.2 Vesicles; mesostasis Red-brown; granular to massive either filling or lining vesicles and cavities. Saponite 0.2 Vesicles Green; fibrous to granular; fills to lines vesicles and cavities. Celadonite 2.5 Vesicles; mesostasis Yellow to pale brown; granular; lines vesicles and can be pure or mixed with celadonite. Pyrrhotite + pyrite Tr Vesicles; alteration halo Small anhedral grains (<=0.02mm) located at the front of the alteration halo and within vesicles. One 0.3mm irregular pyrite grain fills the end of an irregular cavity. VESICLES/ CAVITIES PERCENT LOCATION SIZE (mm) FILLING SHAPE COMMENTS: Gas vesicles 1.7 Even 0.05-0.15 None-clay Round to ovoid "Iddingsite, saponite and celadonite partially to completely fill the vesicles. The type of clay filling the vesicle depends on its location in the alteration halo." Cavities 1.7 Concentrated at the top. 0.1-1.5 None-clay Irregular "The cavities are filled in a similar manner to the vesicles. They are irregular and convolute in shape, and occur in the upper half of the section, with their long axes parallel to the top of the rock." COMMENTS: "The alteration halo is c.5mm thick and zoned consisting of a sequence of iddingsite, celadonite and saponite from the external surface in towards the center of the rock."