Leg : 31 Top/Bottom Interval(mm): 900/ 930 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 516.00 Rock Type: IGNEOUS
Core: 18 Sample Midpoint(m) : 516.92 Sect/Pc #: 1/PCE 2
ROCK = BASALT
DARK GREENISH GRAY;
Texture: OPHITIC
Groundmass - PLAGIOCLASE ( 40%)
Size(mm): 1X.06 Morphology: LATH-LIKE
APPROX COMP AN50;
CLINOPYROXENE
OPAQUE MINERALS ( 8%)
SCATTERED*
Alteration - AMPHIBOLE ( 52%)
PALE GREEN,ALTERED AFTER CPX,ALL CPX NOW
COMPLETELY ALTERED*
Leg : 31 Top/Bottom Interval(mm): 1080/1110 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 521.00 Rock Type: IGNEOUS
Core: 19 Sample Midpoint(m) : 522.10 Sect/Pc #: 1/PCE 1
ROCK = BASALT
ALTERED THOLEIITE;
Texture: OPHITIC*
Groundmass - PLAGIOCLASE ( 55%)
Size(mm): 1.5X.05 Morphology: TABULAR
APPROX COMP AN50;
CLINOPYROXENE ( 37%)
Morphology: POIKIOLITIC-GRANULAR
INTERGROWTH OF PLAG WITH CPX;
OPAQUE MINERALS ( 5%)
SCATTERED,HIGHLY ALTERED, SECTION IS CUT BY A ZONE
OF MICROBRECCIATION GIVING ZONE OF FOLIATION
MARKED BY BROKEN PLAG AND PYX WITH ABUNDANT
CHLORITE*
Alteration - CHLORITE ( 3%)
ABUNDANT*
Leg : 31 Top/Bottom Interval(mm): 1430/1480 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 521.00 Rock Type: METAMORPHIC
Core: 19 Sample Midpoint(m) : 522.46 Sect/Pc #: 1/PCE 6
ROCK = BASALTIC BRECCIA
ALTERED,
CLASTS OF GREENSCHISTS WITH VARYING DEGREES OF
SCHISTOSITY,NOW COMPLETELY ALTERED TO CHLORITE-
ALBITE AND SCATTERED OPAQUES,GROUNDMASS OF PLAG,
CHLORITE AND ALTERED FE-OXIDE GRAINS IN CLAY-SIZED
MATRIX;
Alteration - CHLORITE
OTHER
CHLORITE-ALBITE*
FERROUS OXIDE
Leg : 31 Top/Bottom Interval(mm): 360/ 450 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 525.50 Rock Type: METAMORPHIC
Core: 20 Sample Midpoint(m) : 525.91 Sect/Pc #: 1/
ROCK = BASALTIC BRECCIA;
GREENSCHIST FACIES SCHISTS OF DEFORMED GABBROS,
CLASTS SET IN A MATRIX OF AMPH+OXIDE+PLAG MINERAL
FRAGMENTS (0.4MM) IN CLAY-SIZED MATRIX PROBABLY
RICH IN GOETHITE GIVING REDDISH COLOR -MATRIX
ALSO RICH IN CARB (5%)*
Groundmass - CLINOPYROXENE
RELICT;
PLAGIOCLASE
Alteration - AMPHIBOLE
Location: MATRIX
GOETHITE
Location: MATRIX
GIVES REDDISH COLOR;
OXIDE
Location: MATRIX
CARBONATE ( 5%)
Location: MATRIX
Leg : 31 Top/Bottom Interval(mm): 1000/1030 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 525.50 Rock Type: IGNEOUS
Core: 20 Sample Midpoint(m) : 526.52 Sect/Pc #: 1/PCE 14
ROCK = MICROGABBRO;
Groundmass - PLAGIOCLASE ( 45%)
Size(mm): .5-1.5 Morphology: EUHEDRAL TABULAR-SUBHEDRAL
CLINOPYROXENE ( 20%)
IN GROUNDMASS OF INTERSTITIAL CPX;
NOW LARGELY ALTERED TO AMPHIBOLE(PALE GREEN)-
AMPHIBOLE ALSO IN SMALL VEINLETS AND LARGE
IRREGULAR PATCHES*
Alteration - AMPHIBOLE ( 35%)
Location: VEINLETS, Replacing: CPX
Location: PATCHES
Leg : 31 Top/Bottom Interval(mm): 1050/1100 Describer: DSDP microfilm
Hole: 293 Top of Core Depth(m) : 525.50 Rock Type: SEDIMENTARY
Core: 20 Sample Midpoint(m) : 526.58 Sect/Pc #: 1/PCE 15
ROCK = GABBROIC BRECCIA
GABBRO CLASTS+MINERAL GRAINS CLOSE PACKED IN
MATRIX OF CHLORITE;
Where sampled: TOP OF ROCK;
Texture: EQUIGRANULAR
MOST FRAGMENTS SKEWED+ALTERED*
Groundmass - PLAGIOCLASE ( 55%)
ALBITE EXTINCTION 24-25DEGREES-APPROX COMP AN46,
ALBITE 010 EXTINCTION 36DEGREES-APPROX COMP AN64,
MINERAL FRAGMENTS: FELDSPAR > CPX > OPX;
CLINOPYROXENE ( 45%)
PARTIALLY URALITIZED;
ORTHOPYROXENE ( 5%)
HIGHLY ALTERED*
Alteration - CHLORITE ( 5-10%)
Location: MATRIX
ID UNCERTAIN FOR CHLORITE,VERY DIFFICULT TO
RESOLVE IN THIS SLIDE-ROCK FRAGMENTS+MINERAL
GRAINS FORM CLOSED FRAMEWORK*
Leg : 31 Top/Bottom Interval(mm): 1050/1100 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 525.50 Rock Type: SEDIMENTARY
Core: 20 Sample Midpoint(m) : 526.58 Sect/Pc #: 1/PCE 15
ROCK = GABBROIC BRECCIA
CLAST OF COARSE-GRAINED GABBRO IN MATRIX COMPOSED
OF MINERAL FRAGMENTS OF AMPHIBOLE + PLAG + MINOR
CPX IN CLAY-SIZED MATRIX WITH CALCITE;
Where sampled: BOTTOM OF PCE 15*
Groundmass - PLAGIOCLASE ( 40%)
CLINOPYROXENE ( 30%)
ORTHOPYROXENE ( 20%)
Alteration - AMPHIBOLE ( 10%)
Location: MATRIX
CALCITE
Leg : 31 Top/Bottom Interval(mm): 1360/1390 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 525.50 Rock Type: IGNEOUS
Core: 20 Sample Midpoint(m) : 526.88 Sect/Pc #: 1/PCE 18
ROCK = GABBRO;
Groundmass - PLAGIOCLASE ( 60%)
Size(mm): 2-4 Morphology: SUBHEDRAL-ANHEDRAL
WELL-TWINNED,SHOWS ZONING;
CLINOPYROXENE ( 32%)
Morphology: INTERSTITIAL
ABUNDANT EXSOLUTION,PARTIALLY ALTERED TO
AMPHIBOLE;
OPAQUE MINERALS ( 3%)
Morphology: EUHEDRAL-SUBHEDRAL
SCATTERED*
Alteration - AMPHIBOLE ( 5%)
Replacing: CPX
Leg : 31 Top/Bottom Interval(mm): 50/ 80 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: IGNEOUS
Core: 21 Sample Midpoint(m) : 535.07 Sect/Pc #: 1/PCE 1
ROCK = GABBRO;
Groundmass - PLAGIOCLASE ( 50%)
Size(mm): 4-6 Morphology: TABULAR-ANHEDRAL
APPROX COMP AN50;
CLINOPYROXENE ( 30%)
Morphology: INTERSTITIAL
ABUNDANT EXSOLUTION,BOTH PARALLEL(100)AND(001),
NOW ALTERED TO AMPHIBOLE LARGELY;
OPAQUE MINERALS ( 2%)
Alteration - AMPHIBOLE ( 18%)
Replacing: CPX
Leg : 31 Top/Bottom Interval(mm): 320/ 350 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: IGNEOUS
Core: 21 Sample Midpoint(m) : 535.34 Sect/Pc #: 1/PCE 4
ROCK = GABBRO;
Groundmass - PLAGIOCLASE ( 45%)
Size(mm): 1.2X.05 Morphology: TABULAR
ARRANGED ESSENTIALLY PARALLEL TO EACH OTHER GIVING
ROUGH FOLIATION,APPROX COMP ANORTHITE;
CLINOPYROXENE ( 44%)
Morphology: INTERSTITIAL
HAS DIALLAGE-TYPE EXSOLUTION;
OPAQUE MINERALS ( 1%)
ORTHOPYROXENE ( 10%)
Morphology: INTERSTITIAL+POIKIOLITIC
VERY FINE EXSOLUTION LAMELLAE*
Leg : 31 Top/Bottom Interval(mm): 720/ 790 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: METAMORPHIC
Core: 21 Sample Midpoint(m) : 535.76 Sect/Pc #: 1/PCE 11
ROCK = IGNEOUS BRECCIA
CLASTS COMPOSED OF VARIOLITIC BASALT+GABBRO +
HORNBLENDE-PLAGIOCLASE SCHIST AND GABBROS ALTERED
TO GREENSCHIST METAMORPHIC FACIES, MATRIX
COMPOSED OF PLAG+PYX WITH MINOR AMPH + OXIDES IN
FINE-GRAINED CLAY MATRIX;
Groundmass - HORNBLENDE
PLAGIOCLASE
Alteration - AMPHIBOLE
Location: MATRIX
OXIDES
Location: MATRIX
CLAY
Location: MATRIX
Leg : 31 Top/Bottom Interval(mm): 110/ 140 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: IGNEOUS
Core: 21 Sample Midpoint(m) : 536.63 Sect/Pc #: 2/PCE 2
ROCK = GABBRO
IGNEOUS BRECCIA;
Texture: COARSE-GRAINED*
Groundmass - PLAGIOCLASE ( 64%)
Size(mm): 2-4 Morphology: SUBHEDRAL-IRREGULAR
APPROX COMP AN45 WELL-DEVELOPED TWINNING,SLIGHT
ZONING,MARGINS OF A NUMBER OF PLAG XTLS MERGE INTO
A MYRMEKITIC INTERGROWTH OF PLAG+QUARTZ;
CLINOPYROXENE ( 30%)
Morphology: IRREGULAR-INTERSTITIAL
FILLED WITH LAMELLAE OF OPX;
ORTHOPYROXENE ( 3%)
SEEMS TO BE EXSOLVING OUT OF CPX TO FORM SEPARATE
GRAINS-OPX OFTEN AS THIN RINDS ON LARGE CPX XTLS
OR AS IRREGULAR XTLS POIKILITICALLY ENCLOSED IN
CPX;
OPAQUE MINERALS ( 1%)
FEW,SCATTERED;
OTHER ( 2%)
MYRMEKITIC INTERGROWTH OF PLAG+QUARTZ*
Leg : 31 Top/Bottom Interval(mm): 620/ 670 Describer: DSDP microfilm
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: IGNEOUS
Core: 21 Sample Midpoint(m) : 537.15 Sect/Pc #: 2/PCE 7
ROCK = GABBROIC BRECCIA;
BRECCIA COMPOSED OF GABBROIC ROCK FRAGMENTS(PARTLY
SKEWED),PLAG,CPX,OPX-ALL SUSPENDED IN REXTLLIZED
MATRIX OF CALCITE,MINERAL FRAGMENTS: PLAG > CPX >
OPX - ALL ANGULAR;
Texture: EQUIGRANULAR
LARGE POIKILITIC OPX SURROUNDED BY CPX+PLAG,SOME
FRAGMENTS HIGHLY SKEWED-SKEWING DOES NOT EXTEND
INTO MATRIX*
Phenocrysts- PLAGIOCLASE
Groundmass - PLAGIOCLASE ( 50%)
APPROX COMP AN58,AN54,AN54-EACH SEPARATE
MEASUREMENT ON PLAG PHENO;
CLINOPYROXENE ( 25%)
ORTHOPYROXENE ( 25%)
LARGE POIKILITIC GRAINS INCLUDING NUMEROUS PLAG
LATHS OF APPROX COMP AN44(MORE SODIC THAN LARGER
PLAG PHENOS);
Alteration - CARBONATE
Replacing: MATRIX
ACTUALLY NOW A CACO3 CEMENT WHICH HAS PROBABLY
REPLACED ORIGINAL ROCK MATERIAL-MATRIX COMPOSES AN
OPEN FRAMEWORK BETWEEN MINERAL+ROCK FRAGMENTS SO
MUST BE REPLACEMENT AND NOT TRUE CEMENT*
Leg : 31 Top/Bottom Interval(mm): 670/ 700 Describer: DSDP microfilm
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: IGNEOUS
Core: 21 Sample Midpoint(m) : 537.19 Sect/Pc #: 2/PCE 7
ROCK = GARROIC BRECCIA
COARSE-GRAINED GABBRO CLASTS IN FINE-GRAINED
MATRIX OF GABBROIC MINERAL FRAGMENTS IN GROUNDMASS
OF CALCITE,MATRIX COMPOSED OF MINERAL FRAGMENTS
FROM GABBRO IN GROUNDMASS OF CLAY SIZED MATERIAL
AND CALCITE;
Texture: COARSE-GRAINED*
Groundmass - PLAGIOCLASE ( 45%)
Size(mm): 1.2X.8 Morphology: EUHEDRAL-SUBHEDRAL LATH-LIKE
SHOWS FAINT PARALLELISM OF ORIENTATION INTERGROWN
WITH INTERSTITIAL CPX AND LARGE (6MM) POIKILITIC;
CLINOPYROXENE ( 33%)
FINE EXSOLUTION LAMELLAE PRESENT;
ORTHOPYROXENE ( 20%)
FINE EXSOLUTION LAMELLAE PRESENT;
OPAQUE MINERALS ( 2%)
Alteration - CALCITE
Location: MATRIX
Leg : 31 Top/Bottom Interval(mm): 850/ 900 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: METAMORPHIC
Core: 21 Sample Midpoint(m) : 537.38 Sect/Pc #: 2/PCE 9
ROCK = DIORITE-GNEISS
IGNEOUS BRECCIA,
BOTTOM PART SIMILAR TO 31-293-21-2 94-97,TOP PART
DESCRIPTION FOLLOWS:
TOP PART IS COMPOSED OF QUARTZ-PLAG-PYX-DIORITE,
GNEISS CLASTS IN GROUNDMASS(BIMODAL)OF QUARTZ,
PLAG AND OPAQUE GRAINS IN CLAY SIZED MATRIX OF
CHLORITE;
Groundmass - QUARTZ ( 15%)
Morphology: ANGULAR
PLAGIOCLASE ( 57%)
APPROX COMP AN35;
CLINOPYROXENE ( 20%)
ALTERED TO CHLORITE IN MATRIX;
OPAQUE MINERALS ( 8%)
Alteration - CHLORITE
Location: MATRIX Replacing: CPX
CALCITE
MINOR*
Leg : 31 Top/Bottom Interval(mm): 940/ 970 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: IGNEOUS
Core: 21 Sample Midpoint(m) : 537.46 Sect/Pc #: 2/PCE 9
ROCK = OPX GABBRO
IGNEOUS BRECCIA,
GROUNDMASS BIMODAL IN GRAIN SIZE,MINERAL FRAGMENTS
FROM LOCAL GABBRO(.1-.5MM)SET IN FINE-GRAINED(.001
TO .005MM)MATRIX OF CHLORITE AND SERPENTINE
MINERALS,FRAGMENTS ARE ANGULAR;
Alteration - CHLORITE
Location: MATRIX
SERPENTINITE
Location: MATRIX
CARBONATE ( <2%)
SMALL AMOUNTS OF AUTHIGENIC CARBONATE*
Leg : 31 Top/Bottom Interval(mm): 1270/1320 Describer: MacGregor, I.
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: IGNEOUS
Core: 21 Sample Midpoint(m) : 537.80 Sect/Pc #: 2/PCE 13
ROCK = GABBRO;
Texture: CUMULATE*
Groundmass - PLAGIOCLASE
Size(mm): .8X.04 Morphology: TABULAR EUHEDRAL-SUBHEDRAL
SHOWS WELL-DEFINED PARALLELISM,SET IN A MATRIX OF
INTERSTITIAL CPX+OPX;
CLINOPYROXENE
EXSOLUTION PRESENT;
ORTHOPYROXENE
EXSOLUTION PRESENT,INVARIABLY ENCLOSES SMALLER
(.3-.4MM)GENERATION OF PLAG XTLS POIKIOLITICALLY*
Leg : 31 Top/Bottom Interval(mm): 1350/1380 Describer: DSDP microfilm
Hole: 293 Top of Core Depth(m) : 535.00 Rock Type: IGNEOUS
Core: 21 Sample Midpoint(m) : 537.87 Sect/Pc #: 2/PCE 13
ROCK = GABBROIC BRECCIA;
BASEMENT BRECCIA,GABBRO CLASTS+CPX,PLAG,OPX
SUSPENDED IN MATRIX COMPOSED PRIMARILY OF
CHLORITE, MATRIX PRIMARILY CHLORITE WITH MINORS
CALCITE(<2% OF MATRIX), NO DISCRETE SHEAR ZONES
IN MATRIX THOUGH SOME OF CLASTS SHOW DEFORMATION,
MATRIX MAKES UP 35-40% OF ROCK AND CLASTS 60-65%,
FRAMEWORK MOSTLY CLOSED WHEN ALL FRAGMENTS
CONSIDERED;
Texture: EQUIGRANULAR;
Groundmass - PLAGIOCLASE ( 60%)
APPROX COMP AN65-60;
CLINOPYROXENE ( 30%)
ORTHOPYROXENE ( 10%)
POIKILITIC WITH INCLUDED PLAG*
Alteration - CHLORITE
Location: MATRIX
CALCITE ( <2%)
Location: MATRIX
MINOR*
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