Table T2. Summary of lithologic and alteration features of units described in Hole 1189A.

Table T2. Summary of lithologic and alteration features of units described in Hole 1189A.

Unit Core, section
(Piece)
Curated depth (mbsf) Curated
length
(m) Lithology Alteration

Top

Base

193-1189A-

1 1R-1 (1-4) 0.00 0.17 0.17 Fresh, moderately vesicular, aphyric dacite. Fresh unit. Minor sulfate films coat vesicles. XRD mineralogy: plagioclase and opaline silica dominant, minor augite, quartz, and spinel.

2 1R-1 (5-8)2R-1 (1-13) 0.179.70 0.3410.63 0.170.93 Moderately to completely altered, moderately vesicular, aphyric dacite. Bleached unit. Vesicles are filled with anhydrite. Rare Fe oxide films. XRD mineralogy: plagioclase, cristobalite, anhydrite dominant, minor pyrite, chlorite/smectite-mixed-layer clays, and traces of chlorite and illite.

3 2R-1 (14) 10.63 10.71 0.08 Coarse-grained quartz-sulfate vein. Gray silica-sulfate-clay-pyrite vein. Coarse-grained sulfate occurs as vuggy cavity fill. Very fine grained pyrite is disseminated throughout and is concentrated in vugs.

4 2R-1 (15-17) 10.71 11.07 0.36 Hydrothermal breccia with completely altered, perlitic volcanic clasts. Volcanic rock with remnant perlitic texture altered pervasively to silica clay and fractured by an anhydrite-silica-pyrite stockwork. Fragments are cut by fine anastomosing networks of sulfate veinlets. Anhydrite occurs as vesicle fill. Pyrite occurs in veins and as vesicle fill. XRD mineralogy: anhydrite, cristobalite dominant, minor pyrite and chlorite, and traces of illite.

5 3R-1 (1-9) 19.40 19.96 0.56 Highly to completely bleached, moderately vesicular, aphyric dacite. Pervasively bleached unit. Pyrite occurs as fine disseminations, as vesicle fill with anhydrite and on fracture surfaces. Veins also contain scattered, coarse-grained anhydrite. XRD mineralogy: plagioclase, cristobalite dominant, minor pyrite, and chlorite.

6 3R-1 (10) 19.96 20.03 0.07 Hydrothermal breccia. White sulfate-rich volcanic clasts cemented in bluish green sulfate-clay-silica altered material. Pyrite is disseminated throughout. A single blue clay altered rounded fragment contains anhydrite laths that do not extend into the body of the rock, implying earlier alteration. XRD mineralogy: anhydrite, quartz dominant, minor pyrite, and traces of illite.

7 3R-1 (11-16) 20.03 20.36 0.33 Variably bleached and silicified, sparsely to moderately vesicular, intensely veined volcanic rock. Silicified bleached vesicular volcanic rock. Medium-grained anhydrite-quartz-pyrite veins with silica-pyrite halos cut the rock. Pyrite occurs in vein halos, but also scattered throughout the rock. XRD mineralogy: quartz dominant, minor orthoclase, pyrite, and traces of illite.

8 4R-1 (1-3) 29.10 29.34 0.24 Completely altered, moderately vesicular dacite. Pervasive green silica-clay alteration, cut by irregular quartz-pyrite veins. Silicate fills vesicles, implying silica flooding of the rock. Rock cut by late anhydrite vein. XRD mineralogy: quartz dominant, minor plagioclase, chlorite, pyrite, and illite.

9 5R-1 (1-9)6R-1 (1-10) 38.8048.60 39.4249.29 0.620.69 Completely altered, hydrothermal breccia with flow-laminated volcanic clasts. Patchy to pervasive multiphase alteration. Stage 1: alteration of volcanics to white clay-anhydrite-silica (locally preserving flow banding). Stage 2: hydraulic brecciation with chlorite alteration associated with anhydrite veining. Stage 3: quartz-pyrite veining with associated chlorite alteration. XRD mineralogy: quartz dominant, minor anhydrite, chlorite, pyrite, and illite.

10 7R-1 (1-8) 58.30 58.88 0.58 Completely altered, nonvesicular to slightly vesicular volcanic rock. Pervasive green silica-clay alteration overprinted by silicification, which is most intense along quartz-pyrite veins. Anhydrite in the centers of some veins. Elongate vesicles sometimes form tube-like structures that are lined with quartz and pyrite and rare late anhydrite. XRD mineralogy: quartz, plagioclase dominant, minor anhydrite, pyrite, chlorite, and illite.

11 7R-1 (9-10) 58.88 59.02 0.14 Completely altered breccia with possible evidence of clast rotation of flow-laminated fragments. Clasts show silica-sulfate-chlorite alteration and are cemented in fine grained silica.

12 7R-1 (11-14) 59.02 59.22 0.20 Completely altered sparsely vesicular volcanic rock. Extensive pervasive silicification overprinting silica-clay alteration. Vesicles are lined with large euhedral quartz and pyrite crystals.

13 7R-1 (15-16) 59.22 59.29 0.07 Completely altered breccia with possible evidence of clast rotation of flow-laminated fragments. Clasts show green silica-clay alteration and are cemented in fine grained silica. XRD mineralogy: quartz dominant, minor plagioclase, chlorite, and traces of pyrite.

14 7R-1 (17) 59.29 59.32 0.03 Massive silica-Fe oxide-pyrite with minor pale green altered clasts. Rare, whitish green altered clasts and fine pyrite euhedra are cemented in a red jasperoid cement.

15 8R-1 (1-20) 68.00 69.28 1.28 Plagioclase-rich sparsely vesicular volcanic rock with patchy poikiliblastic silicification associated with a fine network of silica-pyrite veins. Plagioclase-rich rock overprinted by patchy poikiloblastic silicification. Veins are abundant and are filled with quartz and pyrite in approximately equal proportions. XRD mineralogy: plagioclase dominant, minor quartz, K-feldspar, pyrite, traces of smectite, chlorite, and illite.

16 9R-1 (1-12) 77.70 78.56 0.86 Completely altered hydrothermal breccia with abundant flow-banded clasts. Rocks are composed of green silica-clay altered material, which is cut by a network of quartz and pyrite veins with heavily silicified in halos along the veins. XRD mineralogy: anhydrite, quartz dominant, minor plagioclase, pyrite, and traces of chlorite.

17 9R-1 (13)10R-1 (1-2) 78.5687.30 78.5987.37 0.030.07 Completely bleached moderately vesicular volcanic rock. Completely bleached and slightly silicified. XRD mineralogy: quartz dominant, minor plagioclase, pyrite and traces of chlorite.

18 10R-1 (3) 87.37 87.41 0.04 Completely altered and mineralized breccia. Clasts of glassy volcanic rock and sulfide (pyrite + chalcopyrite) in a very fine grained silica-pyrite cement.

19 10R-1 (4-14) 87.41 88.72 1.31 Completely altered hydrothermal breccia with medium- to fine-grained clasts hosted in a network of silica-sulfide veins with late anhydrite vug fill. Silica-clay alteration overprinted by silicification. Bluish gray domains in the core are heavily silicified, while greenish domains are soft (clayey). Quartz and pyrite veins often have anhydrite vug fill. XRD mineralogy: quartz and anhydrite dominant, minor plagioclase and pyrite, traces of chlorite and illite.

20 11R-1 (1-13)12R-1 (1-15) 96.90106.50 98.07107.70 1.171.20 Completely silicified, massive, moderately vesicular volcanic rock. Intense silicification overprinting patchily preserved green clay alteration. Vugs and vesicles are commonly lined with quartz and pyrite. Pyrite veins commonly have silicified halos. XRD mineralogy: quartz dominant, minor pyrite, illite, and chlorite.

21 12R-1 (16) 107.70 107.78 0.08 Completely altered and mineralized volcaniclastic breccia. Clasts of glassy volcanic rock and sulfide (pyrite + minor chalcopyrite) in a very fine grained silica-pyrite cement.

22 12R-1 (17-18)13R-1 (1-7) 107.78116.10 107.88116.61 0.100.51 Pervasively bleached moderately vesicular volcanic rock with a patchy silica overprint. Vesicular intensely bleached volcanic unit with patchily developed indurated silicification. Widespread pyrite as vesicle lining. XRD mineralogy: quartz dominant, minor chlorite, pyrite, illite.

23 13R-1 (8) 116.61 116.69 0.08 Polymict volcaniclastic breccia, with rounded green clay, altered gray silicified and bleached clasts cemented in silica. Three distinct clast types, all showing differing alteration types, suggesting a polymict nature. Most of the more clay-rich pieces have silicified rims adjacent to the silceous cement. Traces of disseminated pyrite. XRD mineralogy: quartz dominant, minor plagioclase, pyrite and chlorite, and traces of illite.

24 13R-1 (9-10) 116.69 116.82 0.13 Pervasively bleached sparsely vesicular volcanic rock with a patchy silica overprint. Vesicular intensely bleached volcanic unit with patchily developed indurated silicification. XRD mineralogy: quartz dominant, minor pyrite and, traces of chlorite and illite.

Unit	Core, section (Piece)	Curated depth (mbsf)	Curated length (m)	Lithology	Alteration
Top	Base
	193-1189A-
1	1R-1 (1-4)	0.00	0.17	0.17	Fresh, moderately vesicular, aphyric dacite.	Fresh unit. Minor sulfate films coat vesicles. XRD mineralogy: plagioclase and opaline silica dominant, minor augite, quartz, and spinel.
2	1R-1 (5-8)2R-1 (1-13)	0.179.70	0.3410.63	0.170.93	Moderately to completely altered, moderately vesicular, aphyric dacite.	Bleached unit. Vesicles are filled with anhydrite. Rare Fe oxide films. XRD mineralogy: plagioclase, cristobalite, anhydrite dominant, minor pyrite, chlorite/smectite-mixed-layer clays, and traces of chlorite and illite.
3	2R-1 (14)	10.63	10.71	0.08	Coarse-grained quartz-sulfate vein.	Gray silica-sulfate-clay-pyrite vein. Coarse-grained sulfate occurs as vuggy cavity fill. Very fine grained pyrite is disseminated throughout and is concentrated in vugs.
4	2R-1 (15-17)	10.71	11.07	0.36	Hydrothermal breccia with completely altered, perlitic volcanic clasts.	Volcanic rock with remnant perlitic texture altered pervasively to silica clay and fractured by an anhydrite-silica-pyrite stockwork. Fragments are cut by fine anastomosing networks of sulfate veinlets. Anhydrite occurs as vesicle fill. Pyrite occurs in veins and as vesicle fill. XRD mineralogy: anhydrite, cristobalite dominant, minor pyrite and chlorite, and traces of illite.
5	3R-1 (1-9)	19.40	19.96	0.56	Highly to completely bleached, moderately vesicular, aphyric dacite.	Pervasively bleached unit. Pyrite occurs as fine disseminations, as vesicle fill with anhydrite and on fracture surfaces. Veins also contain scattered, coarse-grained anhydrite. XRD mineralogy: plagioclase, cristobalite dominant, minor pyrite, and chlorite.
6	3R-1 (10)	19.96	20.03	0.07	Hydrothermal breccia.	White sulfate-rich volcanic clasts cemented in bluish green sulfate-clay-silica altered material. Pyrite is disseminated throughout. A single blue clay altered rounded fragment contains anhydrite laths that do not extend into the body of the rock, implying earlier alteration. XRD mineralogy: anhydrite, quartz dominant, minor pyrite, and traces of illite.
7	3R-1 (11-16)	20.03	20.36	0.33	Variably bleached and silicified, sparsely to moderately vesicular, intensely veined volcanic rock.	Silicified bleached vesicular volcanic rock. Medium-grained anhydrite-quartz-pyrite veins with silica-pyrite halos cut the rock. Pyrite occurs in vein halos, but also scattered throughout the rock. XRD mineralogy: quartz dominant, minor orthoclase, pyrite, and traces of illite.
8	4R-1 (1-3)	29.10	29.34	0.24	Completely altered, moderately vesicular dacite.	Pervasive green silica-clay alteration, cut by irregular quartz-pyrite veins. Silicate fills vesicles, implying silica flooding of the rock. Rock cut by late anhydrite vein. XRD mineralogy: quartz dominant, minor plagioclase, chlorite, pyrite, and illite.
9	5R-1 (1-9)6R-1 (1-10)	38.8048.60	39.4249.29	0.620.69	Completely altered, hydrothermal breccia with flow-laminated volcanic clasts.	Patchy to pervasive multiphase alteration. Stage 1: alteration of volcanics to white clay-anhydrite-silica (locally preserving flow banding). Stage 2: hydraulic brecciation with chlorite alteration associated with anhydrite veining. Stage 3: quartz-pyrite veining with associated chlorite alteration. XRD mineralogy: quartz dominant, minor anhydrite, chlorite, pyrite, and illite.
10	7R-1 (1-8)	58.30	58.88	0.58	Completely altered, nonvesicular to slightly vesicular volcanic rock.	Pervasive green silica-clay alteration overprinted by silicification, which is most intense along quartz-pyrite veins. Anhydrite in the centers of some veins. Elongate vesicles sometimes form tube-like structures that are lined with quartz and pyrite and rare late anhydrite. XRD mineralogy: quartz, plagioclase dominant, minor anhydrite, pyrite, chlorite, and illite.
11	7R-1 (9-10)	58.88	59.02	0.14	Completely altered breccia with possible evidence of clast rotation of flow-laminated fragments.	Clasts show silica-sulfate-chlorite alteration and are cemented in fine grained silica.
12	7R-1 (11-14)	59.02	59.22	0.20	Completely altered sparsely vesicular volcanic rock.	Extensive pervasive silicification overprinting silica-clay alteration. Vesicles are lined with large euhedral quartz and pyrite crystals.
13	7R-1 (15-16)	59.22	59.29	0.07	Completely altered breccia with possible evidence of clast rotation of flow-laminated fragments.	Clasts show green silica-clay alteration and are cemented in fine grained silica. XRD mineralogy: quartz dominant, minor plagioclase, chlorite, and traces of pyrite.
14	7R-1 (17)	59.29	59.32	0.03	Massive silica-Fe oxide-pyrite with minor pale green altered clasts.	Rare, whitish green altered clasts and fine pyrite euhedra are cemented in a red jasperoid cement.
15	8R-1 (1-20)	68.00	69.28	1.28	Plagioclase-rich sparsely vesicular volcanic rock with patchy poikiliblastic silicification associated with a fine network of silica-pyrite veins.	Plagioclase-rich rock overprinted by patchy poikiloblastic silicification. Veins are abundant and are filled with quartz and pyrite in approximately equal proportions. XRD mineralogy: plagioclase dominant, minor quartz, K-feldspar, pyrite, traces of smectite, chlorite, and illite.
16	9R-1 (1-12)	77.70	78.56	0.86	Completely altered hydrothermal breccia with abundant flow-banded clasts.	Rocks are composed of green silica-clay altered material, which is cut by a network of quartz and pyrite veins with heavily silicified in halos along the veins. XRD mineralogy: anhydrite, quartz dominant, minor plagioclase, pyrite, and traces of chlorite.
17	9R-1 (13)10R-1 (1-2)	78.5687.30	78.5987.37	0.030.07	Completely bleached moderately vesicular volcanic rock.	Completely bleached and slightly silicified. XRD mineralogy: quartz dominant, minor plagioclase, pyrite and traces of chlorite.
18	10R-1 (3)	87.37	87.41	0.04	Completely altered and mineralized breccia.	Clasts of glassy volcanic rock and sulfide (pyrite + chalcopyrite) in a very fine grained silica-pyrite cement.
19	10R-1 (4-14)	87.41	88.72	1.31	Completely altered hydrothermal breccia with medium- to fine-grained clasts hosted in a network of silica-sulfide veins with late anhydrite vug fill.	Silica-clay alteration overprinted by silicification. Bluish gray domains in the core are heavily silicified, while greenish domains are soft (clayey). Quartz and pyrite veins often have anhydrite vug fill. XRD mineralogy: quartz and anhydrite dominant, minor plagioclase and pyrite, traces of chlorite and illite.
20	11R-1 (1-13)12R-1 (1-15)	96.90106.50	98.07107.70	1.171.20	Completely silicified, massive, moderately vesicular volcanic rock.	Intense silicification overprinting patchily preserved green clay alteration. Vugs and vesicles are commonly lined with quartz and pyrite. Pyrite veins commonly have silicified halos. XRD mineralogy: quartz dominant, minor pyrite, illite, and chlorite.
21	12R-1 (16)	107.70	107.78	0.08	Completely altered and mineralized volcaniclastic breccia.	Clasts of glassy volcanic rock and sulfide (pyrite + minor chalcopyrite) in a very fine grained silica-pyrite cement.
22	12R-1 (17-18)13R-1 (1-7)	107.78116.10	107.88116.61	0.100.51	Pervasively bleached moderately vesicular volcanic rock with a patchy silica overprint.	Vesicular intensely bleached volcanic unit with patchily developed indurated silicification. Widespread pyrite as vesicle lining. XRD mineralogy: quartz dominant, minor chlorite, pyrite, illite.
23	13R-1 (8)	116.61	116.69	0.08	Polymict volcaniclastic breccia, with rounded green clay, altered gray silicified and bleached clasts cemented in silica.	Three distinct clast types, all showing differing alteration types, suggesting a polymict nature. Most of the more clay-rich pieces have silicified rims adjacent to the silceous cement. Traces of disseminated pyrite. XRD mineralogy: quartz dominant, minor plagioclase, pyrite and chlorite, and traces of illite.
24	13R-1 (9-10)	116.69	116.82	0.13	Pervasively bleached sparsely vesicular volcanic rock with a patchy silica overprint.	Vesicular intensely bleached volcanic unit with patchily developed indurated silicification. XRD mineralogy: quartz dominant, minor pyrite and, traces of chlorite and illite.

Note: XRD = X-ray diffraction.