|
Core, section,
interval (cm) |
Description
|
Alteration
|
XRD identification
|
|---|---|---|---|
| 183-1140A- |
|
|
|
| 27R-1, 17-27 | Olivine-plagioclase microphyric basalt, weakly vesicular (1%; 0.3 mm), almost completely crystallized, with interstitial texture. Microphenocrysts (5%) of olivine (0.1-0.2 mm) and tabular plagioclase (labradorite; to 0.2-0.5 mm). Groundmass of plagioclase (labradorite-oligoclase; 30%-35% and clinopyroxene (40%-45%) of approximately same size (0.3-0.5 mm, rarely up to 1 mm), opaque minerals (5%), interstitial glass (5%). | 10%; olivine completely replaced by chlorite and smectite; interstitial glass replaced by yellow-brown chlorite and opaque minerals; vesicles infilled with brown-yellow chlorite. Oxidation of basalt is very low (total ~1% of rock). | Smectite with 10% of mica layers |
| 27R-1, 63-67 | Aphyric basalt, vesicular (5%-10%; 0.1-0.8 mm), incompletely crystallized, with vitrophyric-microlitic texture. Groundmass of plagioclase lathe (0.1-0.3 mm) and brown glass with microlites of clinopyroxene and opaque dust. | 5%-10%; vesicles infilled with yellow-green chlorite and carbonate. Oxidation of basalt is low (total ~5% of rock). |
|
| 27R-2, 78-23 | Sparsely plagioclase-phyric basalt, incompletely crystallized, massive, with intersertal, partly microdoleritic, texture. Phenocrysts of plagioclase (2%), central part of plagioclase represented by labradorite-oligoclase and rim-by oligoclase. Groundmass of long lathe of plagioclase (40%-45%; to 0.2-0.3 mm), clinopyroxene (40%-45%), volcanic glass (10%-15%), and opaque minerals (5%). | 10%-15%; labradorite replaced by mica-type mineral; interstitial glass completely replaced by chlorite. Rock is nonoxidized. | Smectite with 20% of mica layers (mixed-layer hydromica-smectite mineral) |
| 31R-1, 9-13 | Olivine-clinopyroxene-plagioclase phyric basalt, weakly vesicular (~2%), incompletely crystallized, with intersertal texture. Phenocrysts (20%) represented by plagioclase (central part of plagioclase represented by labradorite-oligoclase and rim-by oligoclase), clinopyroxene of double, olivine as single grains. Groundmass of lathe of plagioclase (to 0.1-0.2 mm), microlites of clinopyroxene, and volcanic glass with opaque minerals. | 10%-15%; labradorite replaced by mica-type mineral; vesicles infilled with chlorite. Rock is nonoxidized. | Smectite |
| 31R-1, 76-79 | Olivine-clinopyroxene-plagioclase glomerophyric basalt, weakly vesicular (~5%), incompletely crystallized, with intersertal texture. Phenocrysts and microphenocrysts (20%-25%) mainly of plagioclase (labradorite-oligoclase). Groundmass of lathe of plagioclase (35%-40%), microlites of clinopyroxene (30%-35%), and volcanic glass with opaque dust. | ~10%; interstitial glass completely replaced by chlorite; vesicles infilled with chlorite and smectite. Rock is nonoxidized. | Smectite with 30% of mica layers (mixed-layer hydromica-smectite mineral); hydromica in trace amount |
| 32R-3, 5-10 | Olivine-clinopyroxene-plagioclase phyric basalt, weakly vesicular (~5%; to 0.1-0.3 mm), incompletely crystallized, with intersertal, partly poikilophitic, texture. Phenocrysts and microphenocrysts (20%-25%) of plagioclase, isometric clinophyroxene, and olivine. Groundmass of lathe of plagioclase, microlites of clinopyroxene, and volcanic glass with opaque minerals. | ~15%; olivine replaced by smectite and chlorite; interstitial glass completely replaced by chlorite; vesicles infilled with chlorite and smectite. Rock is nonoxidized. | Smectite |
| 32R-4, 17-20 | Olivine-clinopyroxene-plagioclase glomerophyric basalt, weakly vesicular (~2%-3%; to 0.1-0.3 mm), incompletely crystallized, with intersertal texture.Phenocrysts and microphenocrysts (30%-35%) mainly of plagioclase (labradorite oligoclase). Groundmass of lathe of plagioclase, microlites of clinopyroxene, and volcanic glass. | ~15%-20%; interstitial glass replaced by chlorite and smectite; vesicles infilled with chlorite and smectite. Oxidation of rock is low (total ~4%-5% of rock). | Smectite with 15% of mica layers (mixed-layer hydromica-smectite mineral) |
| 34R-1, 117-121 | Olivine-plagioclase glomerophyric basalt, incompletely crystallized, massive, with intersertal texture. Phenocrysts (10%) represented mainly by zoned plagioclase (central part of plagioclase of labradorite and rim-by oligoclase), sometimes plagioclase represented by accretions with olivine. Groundmass of lathe of plagioclase (30%-35%), clinopyroxene (40%-45%), opaque minerals (5%-10%), and interstitial glass (20%-25%). | Moderate (25%-30%); olivine and interstitial glass replaced by chlorite and smectite. Oxidation of rock is very low (total ~2% of rock). | Smectite |
| 34R-3, 100-105 | Olivine-plagioclase glomerophyric basalt, incompletely crystallized, massive, with intersertal, partly doleritic, texture. Phenocrysts (5%-10%) of tabular plagioclase (0.2-1.5 mm, sometimes up to 3 mm) and olivine. Groundmass of lathe of plagioclase (30%-35%, size 0.1-0.7 mm), clinopyroxene (30%-35%, size 0.1-0.3 mm), opaque minerals (5%), and interstitial glass (30%-35%). | Moderate (30%-35%); olivine and interstitial glass replaced by chlorite and smectite. Oxidation of rock is low (total ~2%-5% of rock). | Smectite; swelling chlorite in trace amount |
| 35R-1, 35-42 | Olivine-clinopyroxene-plagioclase microphyric basalt, weakly vesicular (<1%; 0.05-0.6 mm), incompletely crystallized, with vitrophyric-microlitic texture. Phenocrysts (30%-35%) of olivine (0.1-0.3 mm), clinopyroxene (0.1-0.6 mm), and tabular plagioclase (labradorite, oligoclase; to 0.1-0.7 mm). Groundmass of interstitial glass with long lathe of plagioclase. | 10%-15%; olivine replaced by carbonate; interstitial glass replaced by chlorite and smectite; vesicles infilled with chlorite and smectite. Oxidation of rock is low (total ~10%-15% of rock). |
|
| 35R-1, 83-87 | Olivine-clinopyroxene-plagioclase microphyric basalt, weakly vesicular (3%-5%; 0.05-0.3 mm), incompletely crystallized, with vitrophyric-microlitic texture. Phenocrysts (20%-25%) of olivine (0.1-0.3 mm), clinopyroxene (0.1-0.3 mm to 0.5-1 mm), and tabular plagioclase (labradorite; to 0.1 to 0.8 mm). Groundmass of brown glass with lathe of plagioclase, microlites of clinopyroxene and opaque dust. | 8%-10%; olivine replaced by smectite, chlorite, and carbonate; vesicles infilled by smectite, chlorite, and carbonate. Oxidation of rock is low (total ~5% of rock). |
|
| 36R-4, 61-67 | Olivine-clinopyroxene-plagioclase glomerophyric basalt, weakly vesicular (up to 0.2 mm), incompletely crystallized, with intersertal texture. Phenocrysts (10%-15%) of olivine (0.2 to 0.5-0.7 mm), clinopyroxene (0.4-0.8 mm to 2.5-4.5 mm), and tabular plagioclase (labradorite-oligoclase; 0.15-0.5 mm to 0.9-2.7 mm). Groundmass of lathe of plagioclase (40%-45%), isometric crystals of clinopyroxene (40%-45%), opaque minerals (5%), and intersertal glass (10%-15%). | 10%-15%; olivine replaced by smectite and chlorite with opaque minerals; interstitial glass replaced by chlorite and smectite; vesicles infilled by brown-green smectite and chlorite. Oxidation of rock is very low (total ~2% of rock). |
|
| 37R-1, 93-99 | Olivine-clinopyroxene-plagioclase glomerophyric basalt, weakly vesicular (up to 0.2 mm), incompletely crystallized, with intersertal, partly poikilophitic, texture. Phenocrysts (10%-15%) of olivine (0.2 to 0.5-0.7 mm), clinopyroxene (0.4-0.8 mm to 2.5-4.5 mm), and tabular plagioclase (labradorite-oligoclase; 0.15-0.5 mm to 0.9-2.7 mm). Groundmass of lathe of plagioclase (30%-35%), clinopyroxene (45%-50%), opaque minerals (10%-15%), and intersertal glass (10%-15%). | 15%-20%; olivine replaced by smectite and chlorite with opaque minerals; interstitial glass replaced by chlorite and smectite; vesicles infilled by brown-green smectite and chlorite. Rock is nonoxidized. | Smectite with 20%-25% of mica layers (mixed-layer hydromica-smectite mineral); chlorite in trace amount |
| 37R-2, 55-60 | Olivine-clinopyroxene-plagioclase phyric basalt, weakly vesicular (up to 0.2 mm), incompletely crystallized, with intersertal, partly subvariolitic, texture. Phenocrysts and microphenocrysts (20%-25%) of olivine (0.1-0.3 mm to 0.8-0.9 mm), clinopyroxene, and tabular plagioclase (labradorite-oligoclase; 0.2-1 mm to 0.9-2.7 mm). Groundmass of intersertal glass with crystals of clinopyroxene, plagioclase, and opaque minerals. They formed subvariolitic accretions. | Low (5%-10%); olivine replaced by smectite, chlorite, and carbonate; interstitial glass partly replaced by chlorite and smectite; vesicles infilled by smectite and chlorite. Rock is nonoxidized. |
|
Note: XRD = X-ray diffraction.