Table
T4. Summary of lithologic and alteration features of units,
Hole 1189B.
Unit
Core,
section (Piece)
Curated
depth (mbsf)
Curated
length
(m)Lithology
Alteration
Top
Base
193-1189B-
1
1R-1
(1)
31.00
31.29
0.29
Semimassive
sulfide with sparse volcanic rock clasts.
Fragmental
textured massive sulfide and rare soft (GSC altered) vesicular volcanic
fragments (2-3 mm in size). Some white apparently anhydrite-replaced
samples and chalcopyrite fragments are also present. All cemented in a
fine grained pyrite-anhydrite-(quartz) matrix. XRD mineralogy: pyrite,
anhydrite, illite, and chlorite/smectite-mixed layer dominant, minor
gypsum and chalcopyrite, and traces of sphalerite.
2
1R-1
(2)
31.29
31.39
0.10
Completely
altered, moderately vesicular, aphyric rock.
Greenish,
soft GSC altered moderately vesicular (10% vesicles) volcanic rock with
aligned stretched vesicles up to 4 mm x
2 mm in size. Trace pyrite occurs as vesicle lining. XRD mineralogy:
pyrite and muscovite dominant and minor chlorite.
3
2R-1
(1-5)3R-1 (1-8)
40.10
49.7040.60
50.540.50
0.84Breccia
of completely altered volcanic rock clasts in a pyrite-anhydrite stockwork
matrix. Flow banded, vesicular (submillimeter scale), and perlitic clasts.
Some clasts show evidence of rotation.
Soft,
greenish blue volcanic fragments and rubble cemented in and cut by
pyrite-anhydrite-silica stockwork veinlets show ladder textures that
parallel and crosscut flow banding in several pieces. Core 3R contains
completely altered, clayey, light blue-green clasts with disseminated
pyrite (possibly with some amorphous silica) cemented by pyrite +
anhydrite - silica. XRD mineralogy: pyrite, gypsum and anhydrite dominant,
minor quartz, chlorite, illite, and kaolinite?, and traces of smectite.
4
5R-1
(1-5)
69.30
69.85
0.55
Breccia
of completely altered volcanic rock clasts in a pyrite-quartz matrix.
Complete
GSC alteration and disseminated pyrite in volcanic rock clasts. Minor
anhydrite lining vugs in Piece 2. Euhedral quartz crystals line vugs in
Piece 5. XRD mineralogy: pyrite dominant, minor quartz, K-feldspar, and
illite, and traces of chlorite.
5
6R-1
(1-5)
79.00
79.56
0.56
Breccia
of completely altered volcanic rock clasts in quartz-hematite-pyrite
matrix. Some clasts are perlitic. Locally, rare plagioclase phenocrysts
and amygdules are truncated at clast margins.
Volcanic
rock clasts show stockwork of red quartz-hematite and minor gray
quartz-pyrite-hematite veins. Rocks are mostly gray, very fine grained and
soft, but few clasts are light gray and slightly silicified. XRD
mineralogy: quartz dominant, minor K-feldspar, plagioclase, pyrite, and
chlorite, and traces of illite.
6
6R-1
(6)
79.56
79.67
0.11
Massive
sulfide.
Massive
sulfide rock with 90% pyrite, 9% quartz, and 1% anhydrite.
7
6R-1
(7)
79.67
79.78
0.11
Completely
altered, moderately amygdaloidal, aphyric volcanic rock.
Soft
clayey rock with spotty texture owing to dark gray quartz amygdules. XRD
mineralogy: quartz dominant, minor plagioclase, K-feldspar, pyrite, and
chlorite, and traces of illite.
8
7R-1
(1-2)
88.70
88.92
0.22
Breccia
of completely altered volcanic rock clasts in an anhydrite-pyrite-quartz
matrix. Clasts (maximum diameter 4 cm) are clay altered and some are flow
banded or contain submillimeter quartz amygdules.
Breccia
of soft clayey clasts with 2% disseminated pyrite. Late anhydrite fills
vugs. XRD mineralogy: quartz and pyrite dominant, minor k-feldspar, and
traces of illite.
9
8R-1
(1-5)
98.40
98.64
0.24
Completely
altered, slightly vesicular, aphyric volcanic rock. Contains fine,
submillimeter quartz amygdules.
Completely
GSC altered with patchy silicification. Quartz is a common vesicle fill.
Piece 5 has 5% pyrite lining vugs, which also have silicified dark gray
halos. The vugs also contain solitary anhydrite crystals. XRD mineralogy:
K-feldspar dominant, minor pyrite, chlorite, and illite, and traces of
illite-bearing mixed-layer clays.
10
8R-1
(6-8)
98.64
98.75
0.11
Breccia
of completely altered volcanic rock clasts in a pyrite-quartz matrix.
Breccia
contains greenish gray very soft and light greenish gray silicified clasts
in a pyrite-quartz stockwork.
11
8R-1
(9-16)
98.75
99.15
0.40
Completely
altered, silicified, moderately vesicular volcanic rock.
Moderately
silicified rock with quartz-pyrite-anhydrite amygdules. Vesicles are lined
with very fine grained euhedral quartz that is overgrown by pyrite.
12
9R-1
(1-2)
108.10
108.19
0.09
Breccia
of completely altered volcanic rock clasts in a pyrite-quartz matrix.
Clasts (2 cm maximum diameter) are light blue-green and clay rich. Some
show remnant flow banding.
Very
soft clayey rock fragments dissected by pyrite microveinlets. Pyrite is
also disseminated.
13
10R-1
(1-3)
117.90
118.23
0.33
Silica-clay
altered, moderately amygdaloidal, aphyric volcanic rock. Green silicified
rock with vesicles up to 5 mm in size, mostly filled with quartz.
Some
vesicles are lined by anhydrite-pyrite. Several hairline veins of
quartz-anhydrite-pyrite with 1-2 mm dark gray siliceous halos are present.
Traces of honey-yellow sphalerite occur around the edges of quartz
amygdules. The matrix contains trace chalcopyrite. Quartz dominant, minor
chlorite, K-feldspar, plagioclase, and pyrite.
193-1189B-
14
10R-1
(4-7)
118.23
118.53
0.30
Silica-chlorite
altered, spherulitic, flow banded aphyric volcanic rock.
Rocks
contains up to 50% white, (clay-altered?) isolated and coalesced
spherulites (up to 1 mm), which locally contain silica-pyrite kernels. The
groundmass consists of dark green (chloritic?) domains with patches of
dark gray silica pyrite and minor wispy domains of anhydrite-quartz. XRD
mineralogy: quartz dominant, minor chlorite, K-feldspar, anhydrite,
pyrite, and illite.
15
10R-1
(8)
118.53
118.67
0.14
Completely
altered, silicified, massive, moderately vesicular, aphyric volcanic rock.
Pervasive
silica-pyrite alteration. Light gray domain in one fragment contains
abundant, <1-mm, round, quartz crystal aggregates of uncertain origin.
XRD mineralogy: cristobalite and plagioclase dominant, minor K-feldspar
and chlorite, and traces of pyrite.
16
11R-1
(1-2)
127.60
127.74
0.14
Breccia
of completely altered volcanic clasts. Clasts are up to 1 cm in maximum
diameter; some are flow-banded and rotated.
Soft,
light green (chlorite-rich) clasts are completely altered and hosted in a
dark gray siliceous matrix. Locally, the matrix also contains very fine
grained magnetite. XRD mineralogy: quartz dominant, minor anhydrite,
k-feldspar, chlorite, chlorite/smectite-mixed layer, smectite, illite, and
pyrite.
17
11R-1
(3)
127.74
127.77
0.03
Jasperoidal
breccia of completely altered volcanic clasts.
Porous,
vuggy jasperlitic silica-Fe-oxide with very fine grained disseminated
magnetite in patches. Drusy pyrite and shaded anhydrite occur as vug fill.
Volcanic clasts are completely altered and green clay (chlorite?) rich.
XRD mineralogy: quartz dominant, minor anhydrite and pyrite, and traces of
hematite.
18
11R-1
(4-8)
127.77
128.03
0.26
Polymict
breccia of completely altered volcanic clasts. Clasts (blocky, 50% to 70%
of rock, up to 1 cm in maximum diameter) are green, clay-rich, and locally
flow-banded, white clay altered, or light gray and siliceous.
Complete
alteration of volcanic clasts. Green clasts are rich in green clay
(chlorite), white, soft clasts are rich in white clay, and gray clasts are
silicified (locally with minor magnetite). The dark gray matrix is silica
with minor magnetite and pyrite. XRD mineralogy: quartz dominant, minor
K-feldspar, illite, chlorite, and pyrite, and traces of plagioclase.
19
11R-1
(9-10)11R-2
(1-11)11R-3 (1)12R-1
(1-11)12R-2
(1-14)12R-3
(1-10)13R-1
(1-3)
128.03
128.28
129.68
137.30
138.71
140.09
147.00128.28
129.68
129.97
138.71
140.09
140.82
147.200.25
1.40
0.29
1.41
1.38
0.73
0.20Completely
altered, moderately vesicular, aphyric volcanic rock. Vesicles are
elongate and subvertically aligned. Contains black xenoliths (1 to 2 cm).
Silicified
groundmass with fine (up to 0.1 mm) spots of clay. Vesicles are generally
lined or partially filled with green clay (chlorite) and/or anhydrite and
traces of pyrite. Exceptionally large vug in Piece 5 of Section 12R-1
contains green clay, pyrite, barite lining. XRD mineralogy: cristobalite
and plagioclase dominant, minor k-feldspar, quartz, chlorite/smectite-mixed
layer, smectite, illite, and chlorite.
20
13R-1
(4-9)
147.20
147.49
0.29
Breccia
with completely altered volcanic clasts. Locally polymictic in composition
(perlitic, flow-banded, amygdaloidal, and glassy clasts). Perlitic clasts
are common. Some perlitic clasts have fine, submillimeter stretched
amygdules.
Light
green and light gray clasts are completely clay altered. There are some
dark gray silicified clasts. Matrix is quartz-anhydrite with minor pyrite.
XRD mineralogy: quartz dominant, minor plagioclase and pyrite, and traces
of chlorite and barite.
21
13R-1
(10)
147.49
147.59
0.07
Completely
altered, massive, aphyric volcanic rock. Parts of the groundmass are
perlitic.
Green
clay (chlorite) rich, pervasive GSC alteration cut by a fine network of
silica-pyrite veinlets. XRD mineralogy: quartz dominant, minor
plagioclase, and traces of chlorite, illite, and pyrite.
22
14R-1
(1)
156.50
156.60
0.10
Silicified
and mineralized, sparsely vesicular, aphyric volcanic rock.
Highly
silicified and mineralized volcanic rock. Alternating irregular
hematite-bearing and hematite-free bands create a layered structure that
mimics flow banding. Pyrite abundance (up to 10%) varies between different
bands. XRD mineralogy: quartz dominant, minor pyrite, and traces of illite.
23
14R-1
(2-17)14R-2
(1-6)
156.60
157.80157.80
158.091.20
0.29Breccia
of completely altered volcanic rock fragments. Flow banded and perlitic
clasts, locally grading into coherent facies. Local evidence for
synvolcanic intrusion of molten lava into brecciated facies. This unit is
an autoclastic breccia.
Completely
GSC altered rocks. Flow banding is well preserved in clay-anhydrite rich
layers intercalated with rare gray quartz-rich layers. Flow-banded, soft,
white to light greenish gray, incipiently silicified clasts (clay >
anhydrite > quartz) are set in a quartz-rich gray cement (quartz >
clay > anhydrite). Large anhydrite crystals in clasts and matrix,
probably late vug fill. Sphalerite in vugs with quartz and pyrite in
Pieces 6 and 15 of Section 14R-1. XRD mineralogy: anhydrite and quartz
dominant, minor K-feldspar, plagioclase, chlorite, and pyrite.
24
14R-2
(7-8)15R-1 (1)
158.09
166.10158.30
166.160.21
0.06Completely
altered, brecciated, silicified, sparsely vesicular, aphyric volcanic
rock.
Highly
silicified. Narrow bleached halos along pyrite veinlets. Vugs and vesicles
are lined with quartz and pyrite and are overgrown by anhydrite. XRD
mineralogy: quartz dominant, minor pyrite, plagioclase, and K-feldspar.
193-1189B-
25
15R-1
(2-17)15R-2
(1-5)16R-1 (1)
166.16
167.59
175.70167.59
167.97
175.771.43
0.38Brecciated
completely altered and silicified, flow banded volcanic rock. Clast
supported, with abundant flow-banded clasts (maximum diameter >6 cm).
The
unit is in parts autoclastic and shows areas of pseudobrecciated texture
owing to alteration to light greenish gray material along microcracks
associated with virtual loss of flow-banded texture. It is similar to Unit
23, but much more silicified. Overall, the pieces from Section 15R-1 are
similar to each other. Flow banding wraps around a black, irregular,
vesicular xenolith (Piece 16 in Section 15R-1). Locally, flow banding is
overprinted by alteration along fine fractures generating a nodular
pseudoclastic texture. (Piece 1 in Section 16R-1 is interpreted as fall
back). Rare fine (<0.5 mm) ovoid spots filled with sugary quartz and
hematite. XRD mineralogy: cristobalite and plagioclase dominant, minor
k-feldspar, illite, and chlorite, and traces of smectite, chlorite/smectite-mixed
layer, illite-bearing mixed-layer, and pyrite.
26
15R-2
(6-10)16R-1
(2-10)
167.97
175.77168.28
176.440.31
0.67Silicified,
sparsely vesicular, sparsely plagioclase-phyric volcanic rock with
prominent quartz-(pyrite-magnetite) vein network locally fit generating a
jigsaw-fit texture. Plagioclase, (generally 1 vol%), phenocrysts are up to
2 mm (laths or tabular to rounded shapes). Contains rare mafic xenoliths.
Silicified
rock cut by a fine network of quartz-pyrite and quartz magnetite veins.
Siliceous alteration halos (millimeter scale) along veins. Magnetite
occurs in halos of quartz-pyrite veins. XRD mineralogy: cristobalite and
plagioclase dominant, minor k-feldspar and illite, and traces of illite-bearing
mixed-layer, chlorite, smectite, and chlorite/smectite-mixed layer.
27
16R-1
(11-19)16R-2
(1-4)
176.44
177.12177.12
177.520.68
0.40Very
highly altered, moderately vesicular, aphyric volcanic rock with
hieroglyphic groundmass texture. Angular to irregular, shardlike shaped
white groundmass domains (up to 3 mm) are embedded in dark gray
groundmass. Trace of plagioclase phenocryst laths (up to 2 mm). Vesicles
are round to lensoidal (up to 2 cm in maximum dimension) and typically
lined by quartz.
Very
highly altered, silicified rock with fine, white anhydrite/white clay-rich
domains (angular irregular shapes, maximum diameters are 1 to 3 mm).
Vesicles are lined/filled by drusy quartz and/or anhydrite. Locally
chalcopyrite, pyrite, and/or covellite occur in quartz-lined vesicles and
on fracture surfaces. XRD mineralogy: quartz dominant, minor plagioclase,
K-feldspar, chlorite/smectite-mixed layer, and pyrite, and traces of
illite.
28
17R-1
(1-3)
185.30
185.58
0.28
Silicified,
moderately vesicular, aphyric volcanic rock.
Highly
silicified rocks cut by a fine quartz-pyrite vein with a pale halo (silification
overprinting silification). Vesicles are lined by quartz ± traces of
pyrite. Some vesicles are filled with quartz-pyrite in the vein halo. XRD
mineralogy: quartz dominant, minor plagioclase, K-feldspar, and pyrite.
29
17R-1
(4-6)
185.58
185.74
0.16
Breccia
of completely altered, flow banded volcanic clasts (maximum diameter >5
cm). There are clasts with folded flow banding, which is truncated at the
margins. In one clast, flow banding is wrapping around a black, siliceous
xenolith.
Flow-banded
gray-green silicified volcanic rock with rare dark spots that contain
magnetite, hematite, and chlorite. XRD mineralogy: quartz dominant, minor
plagioclase, K-feldspar, pyrite, and chlorite/smectite-mixed layer.
30
17R-1
(7-18)
185.74
186.26
0.52
Silicified,
flow-banded volcanic rock.
Strongly
silicified volcanic rock. Drusy quartz lined and filled vugs in Pieces 7,
10, and 14. Green clay layers occur in flow-banded pieces. Trace of fresh
plagioclase phenocrysts are present in Piece 7. XRD mineralogy: quartz
dominant, minor plagioclase, K-feldspar, pyrite, and chlorite/smectite-mixed
layer.
31
17R-1
(19-20)
186.26
186.34
0.08
Graded,
thinly bedded, volcaniclastic sandstone. Contains a variety of fragments
including perlitic, porphyritic, and glassy clasts.
White,
green, and blue clay fragments are hosted in a hard silicified matrix.
Pyrite occurs as fine drusy crystals in voids and as fine disseminated
crystals. Trace disseminated chalcopyrite. XRD mineralogy: quartz
dominant, minor plagioclase, pyrite, and illite.
32
17R-1
(21-28)18R-1
(1-2)
186.34
195.00186.75
195.120.41
0.12Flow-banded
silicified volcanic rock.
Flow
banding defined by green clay-rich layers. Trace of disseminated magnetite
and pyrite. Magnetite occurs in patches of reddish brown clay and as
disseminations in Piece 28 of Section 17R-1. XRD mineralogy: quartz
dominant, minor plagioclase, K-feldspar, pyrite, and chlorite, and traces
of illite, illite-bearing mixed layer, and chlorite/smectite-mixed layer.
33
18R-1
(3-6)
195.12
195.45
0.33
Breccia
of completely altered, flow-banded volcanic rock.
GSC
altered clasts, with moderate silicification, set in a dark gray matrix of
quartz, hematite, and pyrite. XRD mineralogy: cristobalite and plagioclase
dominant, minor quartz, K-feldspar, illite, and chlorite, and traces of
illite-bearing mixed layer and pyrite.
34
18R-1
(7-21)18R-2
(1-4)
195.45
196.42196.42
196.780.97
0.36Breccia
of completely altered flow banded volcanic rock which is locally
overprinted by silicification along a fine vein network generating a
pseudoclastic texture.
GSC
altered clasts, with gray silicified blebs and silicification along
quartz-hematite vein network. XRD mineralogy: cristobalite and plagioclase
dominant, minor quartz, K-feldspar, pyrite, illite, chlorite, and
chlorite/smectite-mixed layer, and traces of smectite, illite-bearing
mixed layer, talc?, and actinolite?.
193-1189B-
35
18R-2
(5-8)
196.78
197.16
0.38
Completely
altered, clast-supported polymict breccia with spherulitic and flow-banded
clasts (>5 cm in maximum diameter). Abundant evidence for clastic
transport including truncated folded flow banding and rotated flow-banded
clasts.
Various
types of silica-sulfate-clay-altered clasts, with
quartz-hematite-sulfide-bearing matrix. XRD mineralogy: quartz dominant,
minor plagioclase, K-feldspar, and chlorite, and traces of illite and
pyrite.
36
18R-2
(9-15)
197.16
197.57
0.41
Breccia
of completely altered, flow-banded volcanic rock.
GSC
altered clasts with quartz-pyrite-bearing matrix.
Notes: GSC = green silica-clay, XRD = X-ray diffraction.