APPENDIX

Detailed descriptions of core samples recovered during Leg 187 are reported by the Shipboard Scientific Party (2001). In this appendix, I describe petrographic characteristics of lava samples from Leg 187 used in this research. Sample characteristics are as follows:

187-1153A-7W-4, 45-46 cm: Aphyric lava containing only trace amounts of olivine and plagioclase crystals.

 

187-1154A-2R-1, 46-49 cm: Olivine-plagioclase porphyritic lava. Groundmass exhibits an intersertal to intergranular texture.

 

187-1154A-3R-2, 20-22 cm: Olivine-plagioclase glomeroporphyritic lava. Groundmass exhibits an intersertal to intergranular texture. Olivine grains exceed 2.5 mm in diameter in places.

 

187-1154A-4R-1, 66-68 cm: Clinopyroxene-olivine-plagioclase porphyritic lava. Groundmass exhibits an intersertal to intergranular texture. Oscillatory zoning in plagioclase is well defined.

 

187-1154A-7R-1, 110-113 cm: Olivine-plagioclase porphyritic lava. Some occurrence of olivine-plagioclase glomerocrysts. Groundmass exhibits an intersertal to intergranular texture.

 

187-1155A-2R-1, 14-16 cm: Olivine-plagioclase seriatic lava. Groundmass exhibits intersertal texture. Olivine and plagioclase exhibit a small (0.7-1 mm diameter) subpoikilitic glomeroporphyritic texture in places. Larger plagioclase porphyroclasts (1-2 mm in size) exhibit remarkably well defined oscillatory zonings.

 

187-1155A-5R-1, 13-17 cm: Olivine-plagioclase seriatic lava. Small-scale glomeroporphyritic textures consisting of olivine and plagioclase are observed in places. Subpoikilitic relationships between these two minerals are observed in some cases. Groundmass exhibits an intersertal texture.

 

187-1155A-7R-1, 7-10 cm: Plagioclase glomeroporphyritic lava. Small amounts of olivine are contained in the glomerocrysts. Groundmass exhibits an intergranular texture of plagioclase and clinopyroxene. Glomeroporphyritic plagioclase >2 mm in diameter in places.

 

187-1155B-4R-2, 65-67 cm: Olivine-plagioclase glomeroporphyritic lava. Glomeroporphyritic assemblages are >3 mm in diameter in places. Groundmass exhibits an intersertal texture.

 

187-1155B-6R-2, 100-102 cm: Olivine-plagioclase glomeroporphyritic lava. Some of the larger plagioclase porphyroclasts exhibit oscillatory zoning. Some olivine phenocrysts exhibit euhedral shapes.

 

187-1156A-2R-4, 14-16 cm: Olivine-plagioclase porphyritic lava. Groundmass exhibits intersertal to intergranular texture. Plagioclase (and olivine) glomeroporphyritic assemblages are scattered throughout the sample. Olivine grains have relatively euhedral shapes. Spinel grains occur as phenocrysts (up to 0.5 mm in diameter) associated with olivine and/or small spinels and are scattered throughout the groundmass.

 

187-1156A-3R-2, 51-54 cm: Olivine-plagioclase glomeroporphyritic lava. Some larger plagioclase porphyroclasts exhibit oscillatory zoning. Olivine phenocrysts exhibit euhedral to subhedral shapes. Groundmass is partly altered glass and has a hyalophitic texture.

 

187-1156B-2R-2, 13-15 cm: Olivine-plagioclase seriatic lava. Olivine phenocrysts are usually smaller (<0.5 mm in diameter) than plagioclase phenocrysts (1-2 mm in diameter). Small numbers of small spinel grains occur associated with plagioclase glomeroporphyritic assemblages.

 

187-1156B-6R-1, 137-139 cm: Olivine-plagioclase porphyritic lava. Olivine and plagioclase occur in glomeroporphyritic assemblages in places. Groundmass exhibits an intersertal texture. Small spinel grains are associated with olivine phenocrysts.

 

187-1157A-2R-1, 60-64 cm: Olivine-plagioclase porphyritic lava. Plagioclase grains occur as glomeroporphyritic assemblages in places. Larger plagioclase phenocrysts exhibit oscillatory zoning. Groundmass is mostly glassy and has a hyalophitic texture.

 

187-1157A-3R-2, 12-15 cm: Olivine-plagioclase porphyric lava. Some olivine grains exhibit skeletal shapes. Plagioclase and olivine grains form glomeroporphyritic assemblages in places. Groundmass is glassy and has an intersertal texture.

 

187-1157B-6R-1, 130-133 cm: Olivine-plagioclase porphyritic lava. Some olivine grains have skeletal shapes. Subpoikilitic relations between olivine and plagioclase in glomeroporphyritic assemblages are observed. Groundmass has an intersertal texture.

 

187-1158B-4R-1, 88-91 cm: Fine-grained olivine (~0.2 mm in diameter) and plagioclase (~0.5 mm in diameter) microphyric lava. Groundmass has an intersertal to intergranular texture.

 

187-1158C-2R-1, 57-60 cm: Fine-grained (~0.5 mm in diameter) clinopyroxene-plagioclase subophitic lava. Glass and/or its altered products and opaque minerals (titanomagnetite) occupy interstitial areas.

 

187-1160B-4R-1, 48-52 cm: Aphyric holocrystalline lava. Fine-grained (<0.3 mm in diameter) olivine, clinopyroxene, and plagioclase are observed.

 

187-1160B-7R-1, 96-99 cm: Olivine-plagioclase porphyritic lava. Olivine and plagioclase glomeroporphyritic assemblages are observed. Groundmass has an intergranular texture, consisting of olivine, plagioclase, clinopyroxene, and trace amounts of spinel. Larger plagioclase grains exhibit oscillatory zoning.

 

187-1160B-7R-2, 14-16 cm: Olivine-plagioclase porphyritic lava. Olivine and plagioclase glomeroporphyritic assemblages are observed. Groundmass has an intergranular texture, consisting of olivine, plagioclase, and clinopyroxene. Small numbers of spinel grains occur as inclusions in the plagioclase phenocryst.

 

187-1160B-9R-2, 11-14 cm: Olivine-plagioclase porphyritic lava. Some plagioclase grains form glomeroporphyritic assemblages. Groundmass exhibits an intergranular texture, consisting of olivine, plagioclase, and pyroxene.

 

187-1160B-9R-3, 29-32 cm: Aphyric holocrystalline lava. Fine-grained (<0.3 mm in diameter) clinopyroxene and plagioclase grains with small-scale subophitic textures are observed.

 

187-1161A-3R-1, 39-42 cm: Olivine-plagioclase porphyritic lava. Olivine and plagioclase grains form glomeroporphyritic assemblages with subpoikilitic texture in places. Small numbers of spinel grains are scattered in groundmass. Groundmass exhibits intersertal texture.

 

187-1161A-4R-1, 116-119 cm: Sparsely plagioclase porphyritic lava. Plagioclase phenocrysts commonly have oscillatory zoning. Groundmass has subophitic texture with small amounts of glassy material.

 

187-1161B-1W-1, 44-47 cm: Olivine-plagioclase porphyritic lava. Olivine and plagioclase grains form glomeroporphyritic assemblages in places. Groundmass is mostly glassy and has hyalophitic texture.

 

187-1162A-5R-1, 0-4 cm: Medium-grained (>1 mm diameter) equigranular plagioclase gabbroic rocks. Plagioclase grains are fresh, but mafic minerals (olivine and clinopyroxene) are commonly altered into oxide mineral, actinolite, and/or chlorite.

 

187-1164A-3R-1, 45-49 cm: Plagioclase porphyritic lava. Small numbers of olivine grains occur as microphenocrysts. Groundmass has an intergranular to intersertal texture, consisting of olivine, plagioclase, and clinopyroxene.

 

187-1164B-8R-1, 73-75 cm: Olivine-plagioclase porphyritic lava. Small (~0.5 mm diameter) plagioclase and olivine grains form glomeroporphyritic assemblages in places. Some olivine grains have skeletal shapes. Groundmass is glassy and has a hyalophitic to intersertal texture, consisting of olivine and plagioclase.

 

187-1164B-9R-1, 59-61 cm: Olivine-plagioclase porphyritic lava. Some olivine grains have skeletal shapes. Groundmass is glassy and has a hyalophitic to intersertal texture, consisting of olivine and plagioclase.