Core, section,
interval (cm) |
Description
|
|---|---|
| 176-735B- | |
| 90R-1, 123-125 | Medium coarse-grained, leucocratic olivine gabbro. 78% plagioclase, 12% clinopyroxene, 10% olivine, trace sulfides (po > tr > pn > cpy > py), trace oxides (sulfides > oxides), trace amphibole. Olivine <5% altered to smectite (50%), amphibole (40%), talc (5%), and magnetite (5%). Clinopyroxene and plagioclase <1% altered to amphibole. |
| 90R-4, 42-45 | Medium-grained, leucocratic olivine gabbro. 70% plagioclase, 15% clinopyroxene, 15% olivine, trace sulfides (po > pn > cpy), trace oxides (sulfides > oxides), trace amphibole. Olivine 30% altered to smectite (40%), amphibole (40%), talc (15%), and magnetite (5%). Clinopyroxene 20% altered to amphibole. Plagioclase 5% altered to amphibole. |
| 90R-6, 72-77 | Coarse-grained troctolite. 60% plagioclase, 35% olivine, 5% clinopyroxene, trace sulfides (po > tr > pn > cpy > py), trace oxides (sulfides > oxides), trace amphibole. Olivine 20% altered to amphibole (60%) smectite (20%), talc (15%), and magnetite (5%). Clinopyroxene 20% altered to amphibole. Plagioclase 5% altered to amphibole. |
| 91R-1, 106-111 | Medium-grained troctolite. 50% olivine, 45% plagioclase, 5% clinopyroxene, <1% sulfides (po > pn > cpy > py), trace oxides (sulfides > oxides). Olivine 5% altered to amphibole (80%), talc (15%), and magnetite (5%). Clinopyroxene 15% altered to amphibole, plagioclase 5% altered to amphibole. |
| 101R-3, 82-87 | Coarse-grained, oxide-bearing olivine gabbro. 55% plagioclase, 35% clinopyroxene, 8% olivine, 2% oxides (predominantly ilmenite), trace sulfides (po > cpy > pn > py). Olivine 15% altered to amphibole (90%), talc (5%), magnetite (5%). Clinopyroxene 10% altered to amphibole, plagioclase 5% altered to amphibole. |
| 114R-1, 84-90 | Coarse-grained, oxide gabbronorite. 45% plagioclase, 30% clinopyroxene, 15% orthopyroxene 10% oxides (predominantly ilmenite), <1% olivine, trace sulfides (po > cpy > py > pn). Olivine 40% altered to smectite (65%), amphibole (20%), talc 10%, magnetite (5%). |
| 121R-6, 37-42 | Coarse-grained oxide gabbro. 60% clinopyroxene, 35% plagioclase, 5% oxide, trace olivine,trace sulfides along grain boundaries (py > po > cpy > pn) intergrown with trace oxides and brown amphibole. Clinopyroxene 25% altered to amphibole. |
| 123R-4, 106-111 | Medium-grained, olivine gabbro. 55% plagioclase, 35% clinopyroxene, 10% olivine, trace sulfides (common along grain boundaries, tr > po > cpy > pn > py). Olivine 5% altered to smectite (60%), amphibole (35%), magnetite (5%). Plagioclase and clinopyroxene only slightly altered (2%) to amphibole. |
| 124R-1, 48-53 | Medium- to coarse-grained olivine gabbro. 55% plagioclase, 35% clinopyroxene, 10% olivine, trace oxides and sulfides (po > cpy > pn > py). Olivine 5% altered to smectite (60%) amphibole (35%), and magnetite. Plagioclase and clinopyroxene 23% altered to amphibole. |
| 127R-3, 113-117 | Coarse-grained oxide and orthopyroxene bearing olivine gabbro. 50% plagioclase, 30% clinopyroxene, 10% olivine, 3% oxides, 2% orthopyroxene. Olivine 5% altered to amphibole > smectite > talc > magnetite. Clinopyroxene and plagioclase <2% altered to amphibole. Trace sulfides (po > cpy > pn > py). |
| 132R-1, 107-112 | Leucocratic oxide and olivine bearing gabbro. 80% plagioclase, 15% clinopyroxene, 3% oxides, 2% olivine, trace sulfides (po > cpy > pn > py). Olivine 30% altered (70% amphibole, 15% smectite, 10% talc, and 5% magnetite). Clinopyroxene 10% altered to amphibole, plagioclase 2% altered to amphibole. |
| 133R-5, 82-87 | Coarse-grained olivine gabbro. 25% olivine, 15% plagioclase, 60% clinopyroxene, trace oxides and sulfides (po > cpy > pn > py). Olivine is 10% altered to smectite with minor (<10%) magnetite. Clinopyroxene is 5% altered to amphibole, plagioclase is<1% altered to amphibole. |
| 134R-5, 70-75 | Coarse-grained olivine gabbro. 50% plagioclase, 30% clinopyroxene, 20% olivine, trace oxides > sulfides (tr > po > cpy > pn > py). Olivine 5% altered to smectite (85%), magnetite (10%), and amphibole (5%). Clinopyroxene 3% altered to amphibole, plagioclase <1% altered to amphibole. |
| 137R-3, 126-130 | Medium-grained olivine gabbro. Plagioclase 60%, clinopyroxene 25%, olivine 15%, trace sulfides (po > cpy > pn > py) and oxides. Olivine 5% altered to smectite (60%), amphibole (35%), and magnetite (5%). Clinopyroxene 5% altered to amphibole, plagioclase 1% altered to amphibole. |
| 137R-6, 52-58 | Medium coarse-grained olivine bearing oxide gabbronorite. 55% plagioclase, 25% clinopyroxene, 13% orthopyroxene, 5% oxides, 2% olivine, trace sulfides (po > cpy > py). Olivine 30% altered to talc (50%) and magnetite (50%) with minor smectite and amphibole. Orthopyroxene 20% altered to amphibole, clinopyroxene 10% altered to amphibole, plagioclase 1% altered to amphibole. |
| 138R-7, 48-53 | Medium-grained oxide bearing olivine gabbro. 52% plagioclase, 37% clinopyroxene, 10% olivine, 1% oxides, trace sulfides (po > cpy > pn > py). Olivine 5% altered to smectite (50%), magnetite (30%), amphibole (10%), and minor talc. Clinopyroxene 5% altered to amphibole, plagioclase 1% altered to amphibole. |
| 140R-4, 34-40 | Coarse-grained olivine gabbro. 40% plagioclase, 50% clinopyroxene, 10% olivine, trace oxides and sulfides (po > cpy > pn > py). Only trace alteration of olivine to smectite, amphibole, and magnetite, and trace alteration of clinopyroxene and plagioclase to amphibole. |
| 144R-1, 145-150 | Orthopyroxene bearing oxide gabbro. 50% Clinopyroxene, 40% plagioclase, 7% oxides, 3% orthopyroxene,<1% sulfides (po > py > cpy > pn). Pyroxenes are 10% altered to amphibole, plagioclase is 5% altered to amphibole. |
| 144R-4, 66-71 | Oxide bearing olivine gabbro. 52% plagioclase, 40% clinopyroxene, 7% olivine, 1% oxides, trace sulfides (po > cpy > pn > py). Olivine is 3% altered to smectite (60%), amphibole (30%) and magnetite (10%). Plagioclase and pyroxene are 3% altered to amphibole. |
| 146R-3, 102-107 | No section made. From a 10-m thick lithologic interval of coarse-grained olivine gabbro. Sample 176-735B-146R-4, 118-112 cm, is from 2 m lower in the same lithologic interval. |
| 146R-4, 118-122 | Coarse-grained olivine gabbro. 52% plagioclase, 35% clinopyroxene, 13% olivine, trace oxides and sulfides (po > cpy > pn > py). Olivine is slightly altered (2%) to smectite (60%), amphibole (30%), and magnetite (10%). Pyroxene and plagioclase are slightly altered 2% to amphibole. |
| 147R-4, 6-15 | Medium- to coarse-grained oxide bearing olivine gabbro. Plagioclase 64%, clinopyroxene 14%, olivine 20%, oxides 2%, trace sulfides (po > cpy > pn > py). Oxide occurs in clusters as matrix surrounding rounded clinopyroxene crystals. Olivine <1% altered to smectite (80%) and magnetite (10%), clinopyroxene partially recrystallized but <2% altered to amphibole. Plagioclase <1% altered to amphibole. |
| 147R-6, 45-51 | Medium-grained olivine gabbro. 64% plagioclase, 27% clinopyroxene, 8% olivine, trace oxides and rare sulfides (py > po > cpy). Olivine is slightly altered (2%) to smectite (95%) and magnetite (5%). Clinopyroxene is slightly (2%) altered to amphibole. Plagioclase is, for the most part, recrystallized and slightly altered (2%) to amphibole. |
| 159R-1, 121-125 | Coarse-grained olivine gabbro. 54% plagioclase, 40% clinopyroxene, 6% olivine, trace oxides and sulfides (po > cpy > py > pn). Olivine 5% altered to amphibole (90%), smectite (5%), magnetite (5%), and minor talc. Clinopyroxene 5% altered to amphibole, plagioclase 1% altered to amphibole. |
| 171R-3, 62-67 | Medium-grained oxide and olivine bearing gabbro. 48% plagioclase, 47% clinopyroxene, 4% olivine, 1% oxides, trace sulfides (po > cpy > pn > py). Olivine 3% altered to smectite (65%), amphibole (30%), and magnetite (5%). Clinopyroxene 5% altered to amphibole, plagioclase 1% altered to amphibole. |
| 173R-2, 108-113 | Coarse-grained olivine gabbro. 60% plagioclase, 25% clinopyroxene, 15% olivine, trace oxides and sulfides (po > cpy > pn > py). Olivine 10% altered to smectite (90%), amphibole (5%), and magnetite (5%). Clinopyroxene 5% altered to amphibole, plagioclase 1% altered to amphibole. |
| 175R-1, 87-92 | Coarse-grained olivine gabbro. 60% plagioclase, 30% clinopyroxene, 10% olivine, trace oxides and sulfides (po > cpy > pn > py). Olivine 2% altered to smectite with traces of amphibole and magnetite. Clinopyroxene and plagioclase <1% altered to amphibole. |
| 175R-1, 115-120 | Coarse-grained oxide bearing olivine gabbro. 55% plagioclase, 35% clinopyroxene, 8% olivine, 2% oxides, trace sulfides (po > cpy > py > pn). Oxides commonly occur as vermicular intergrowths with altered olivine (10% to amphibole 50%, smectite 20%, magnetite 20%). Plagioclase and clinopyroxene 2% altered to amphibole. |
| 189R-5, 1-4 | Fine- to medium-grained olivine gabbro. 55% plagioclase, 38% clinopyroxene, 7% olivine, trace oxides and sulfides (tr > po > cpy > pn > py). Olivine trace alteration to smectite and minor magnetite. Plagioclase and pyroxene virtually fresh, only a trace of alteration to amphibole. |
| 191R-2, 2-7 | Contact between medium-grained olivine gabbro and coarse-grained gabbro. Olivine gabbro contains 55% plagioclase, 30% clinopyroxene, 15% olivine, and a trace of oxides and sulfides with po > cpy > pn > py. Olivine is 10% altered to smectite (80%), amphibole (10%), and magnetite (5%). Clinopyroxene is 10% altered to amphibole, plagioclase 1% altered to amphibole. Gabbro contains 60% plagioclase and 40% clinopyroxene with the same sulfide assemblage. Oxides are a higher proportion of opaques in olivine gabbro, sulfides are a higher proportion in gabbro. Clinopyroxene in gabbro is 40% altered to amphibole, but varies from nil to 100% in different crystals. Plagioclase is 5% altered to amphibole, particularly where in contact with altered clinopyroxene. |
| 199R-6, 115-120 | Coarse-grained olivine gabbro. 55% plagioclase, 32% clinopyroxene, 8% olivine, 0.5% oxides and a trace of sulfides (po > cpy > py). Olivine is 5% altered to smectite (80%), amphibole, (15%), and magnetite (5%). Clinopyroxene and plagioclase show a trace of alteration to amphibole. |
| 200R-1, 12-16 | Coarse-grained olivine gabbro. 35% plagioclase, 30% clinopyroxene, 35% olivine, trace oxides and sulfides (po > cpy > pn > py) but higher abundance of cpy and pn than most other samples. Olivine 5% altered to amphibole (70%), smectite (25%), and magnetite (1%). Clinopyroxene 2% altered to amphibole, plagioclase <1% altered to amphibole. |
| 201R-5, 9-16 | Coarse-grained gabbro. 65% plagioclase, 35% clinopyroxene, trace oxides and sulfides (po > pn > cpy > py) and sulfides > oxides. Clinopyroxene and plagioclase 5% altered to amphibole with minor smectite. |
| 203R-1, 11-13 | Coarse-grained oxide and sulfide bearing clinopyroxenite (po > cpy > pn). Sulfides and oxides are ameoboid clusters randomly distributed between the rounded edges of clinpyroxene grains and in this section sulfides are 3-4 modal percent of the rock. An adjacent billet has no visible sulfides, and this section could have been cut to show an even higher abundance of sulfides. |
| 207R-1, 18-24 | Medium- to fine-grained olivine gabbro. 60% plagioclase, 35% clinopyroxene, 5% olivine, trace of oxides and sulfides (po > cpy > pn > py). Olivine 20% altered to smectite (70%), amphibole (20%), talc (5%), and magnetite (5%). Plagioclase and clinopyroxene 1% altered to amphibole. |
| 210R-4, 60-63 | Coarse-grained olivine gabbro. 40% plagioclase, 45% clinopyroxene, 15% olivine. Trace oxides and sulfides (po > cpy > pn > py). Olivine 10% altered to smectite (85%), amphibole (10%), magnetite (5%). Clinopyroxene 5% altered to amphibole, plagioclase 1% altered to amphibole. |
Note: tr = troilite, po = pyrrhotite, pn = pentlandite, cpy = chalcopyrite, py = pyrite.