SITE 836 HOLE A CORE 1H CORED mbsf 836A-1H I 1

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1 A-1H SMEAR SLIDE SUMMARY (%): TEXTURE: Sand Silt Clay MPOSITION: Accessry minerals Clay Dfaim Feldspar Fóraminifers Glass Nanπfssils Radilarians Sili dagβllaleε Spiculβs 1,6 D t 1,65 D ,68 M ,85 M _ 1,97 M ,112 D _ HOLE A RE 1H RED mbsf 836A-1H I 1 Meter Graphic Lith.. -i- J- α. j_. Λ. -L JL J. O., -L JL 4. J.. J. J. J. J. 1.0], J. J. a. J.. J- J. 4. α. Sectin Age 1 cc Upper Pleistcene ^ Structure O 0 O O "* O ~ Disturb Sample S SS S Clr 10YR 4/3 Descriptin CLAYEY NANNOFOSSIL OOZE Majr lithlgy: CLAYEY NANNOFOSSIL OOZE, dark brwn (10 YR 4/3). The sediment is hmgenus, but cntains clasts f pumice 1-2 cm in diameter. Minr lithlgies: VOLCANIC SILT WITH CLAY AND NANNOFOSSILS ccurs in Sectin 1, cm. FORAM VOLCANIC SAND ccurs in Sectin 1, cm. CLAYEY NANNOFOSSIL MIXED SEDIMENT WITH GLASS ccurs in Sectin 1, cm. These three layers are all nrmally graded.

2 A-2H SMEAR SLIDE SUMMARY <%): Clay 1,40 1,77 1,140 2,40 2,85 2,139 3,34 D M D. D M M D HOLE A RE 2H RED mbsf Graphic Lith. Structure Descriptin CLAYEY NANNOFOSSIL OOZE, AND CLAYEY NANNOFOSSIL OOZE WITH GLASS 836A-2H MPOSITION: Accessry minerals Clay Diatms Feldspar FraminKers Glass Nannfssils Radilarians Spiculβs 3C β K 5C 2 SMEAR SLIDE SUMMARY (%): Clay MPOSITION: Accessry minerals Clay Diatms Feldspar FraminHers Glass Nannfssils Radidarians Silicflagellates Spiculβs ,119 4,46 4,92 5,36 5,39 5,93 6,32 D M M M D M D SMEAR SLIDE SUMMARY (%) _ S S I P Ss 10YR 4/3 10YR 5/3 Majr lithlgies: CLAYEY NANNO- FOSSIL OOZE and CLAYEY NANNO- FOSSIL OOZE WITH GLASS, brwn t dark brwn (10YR 4/3 t 10YR 5/3). Minr lithlgiβs: VITRIC CLAY WITH NANNOFOSSILS AND FORAMS, brwn t dark brwn (10YR 4/3), CLAYEY NANNOFOSSIL OOZE WITH FORAMS. grayish brwn (10YR 5/2), VITRIC VOLCANIC SILT WITH CLAY, very pale brwn (10YR 7/3) and CLAST-SUPPORTED PUMICE LAPILLI, brwn t dark brwn (10YR 4/3). VITRIC SILT WITH CLAY ccurs in Sectin 1, cm. Sectin 2, cm, and Sectin 6, cm. FORAMINIFERAL VITRIC CLAYEY MIXED SEDIMENT WITH NANNO- FOSSILS ccurs in Sectin 2, cm, VITRIC SILT WITH FORAMS ccurs in Sectin 4, cm, CLAYEY VITRIC SILT ccurs in Sectin 5, cm, and VITRIC NANNOFOSSIL MIXED SEDIMENT ccurs in Sectin 5, cm. TE>CTURE: 6,39 M 6,87 D 7,25 D s 10YR 5/2 MPOSITION: Accessry minerals Clay 20 Diatms Feldspar 2 4/2 Nanntssils Radidarians Spicules

3 A-3H SMEAR SLIDE SUMMARY (%): Clay MPOSITION: Accessry minerals Clay Feldspar Framinifers Glass Nannfssils Radidarians Spiculβs 1,69 2,5 2,26 2,34 2,96 2,102 2,106 D D M D D M D SMEAR SLIDE SUMMARY (%): Clay MPOSITION: Accessry minerals Clay Diatms Feldspar Framinifers Glass Nannfssils Radidarians ,6 3,104 3,122 D D D 5._ SMEAR SLIDE SUMMARY (%): MPOSITION: _ _. 3,127 3, 130 4,27 4,127 M D M M ,14 5,32 5,50 5,80 5,127 6,9 D M M D M D " HOLE A RE 3H RED mbsf 836A-3H 1 Graphic Lith. Structure is ; S S S ;SS 10YR 3/3 10YR 2/1 T 10YR 3/3 10YR 2/1 10YR 4/3 5YR 2.5/1 2.5Y 4\2 10YR 3/3 10YR 4/3 Descriptin CLAYEY NANNOFOSSIL OOZE WITH FORAMS, CLAYEY NANNOFOSSIL VITRIC MIXED SEDIMENT and HYALOCLASTITE Majr lithlgies: CLAYEY NANNO- FOSSIL OOZE, bth with and withut frams, dark brwn (10YR 3/3). MIXED SEDIMENT with varying prprtins f clay, glass, and nannfssils. CLAYEY NANNOFOSSIL VITRIC MIXED SEDIMENT, dark gray (10YR 4/1) t brwn (10YR 4/3), and CLAYEY VITRIC NANNOFOSSIL MIXED SEDIMENT, dark brwn (10YR 3/3) t black (10YR 2/1) are cmmn. HYALOCLASTITE, black (5YR 2.5/1). Minr lithlgies: Graded layers f VOLCANIC SAND and VOLCANIC SILT with varying percentages f glass, nannfssils, and clay ccur within the mixed sediments. Their clr varies frm dark gray brwn (2.5YR 4/2) t black (10YR 2/1). Accessry minerals Clay 20 Feldspar FraminHβrs 10 Glass Nannfssils 70 SMEAR SLIDE SUMMARY (%): 6,11 6,13 6,117 6,124 6,138 7,25 D M M D D J 1 10YR 4/4 Clay MPOSITION: Accessry minerals Clay Feldspar Framinifers Glass Nanntssils _

4 HOLE A RE 4H RED mbsf Graphic Lith. Structure Descriptin I I - > BASALTIC BRECCIA Meter Age Disturb Clr Majr lithlgy: BASALTIC BRECCIA, black (10YR 2/1), uncnslidated, unsrtθd and structureless with clasts up t 23 mm in diameter. Minr lithlgy: Nne. 836A-4H CC : 836A-6X 1 "w ID : : 5. S s. ^^H ls I 20z ~ ls 20 zl i~ ; 25" A 5X HARD ROCK 30 as 30 """" 35 * GA6X SMEAR SLIDE SUMMARY (%) 1,1 M TEXTURE: Sand._ Sill Clay MPOSITION: Fraπiπilers 5 Gθthile 5 Nannlssils 83 Pre space 7 HOLE A Meter Graphic Lith. Sectin Φ RE Structure Disturb 6X Sample Clr RED mbsf Descriptin NANNOFOSSIL CHALK WITH FORAMS AND CLAY Majr lithlgy: NANNOFOSSIL CHALK WITH FORAMS AND CLAY, dark yellwish brwn (10YR 4/4), structureless and indurated. Minr lithlgy: Nne. 836A 7X THROUGH 9X HARD ROCK 40 \ 45 SO I DO _ g, çtr\ 65 _ 7Q_ 75 _ g 30 _ g-! as ( \ ; 120 ; 12s ; i ( i 150

5 R SMEAR SLIDE SUMMARY (%): MPOSITION: Accessr Clay Dialms Dlmite Feldspar Frarninil Glass Na Radilarians Spiculs 1,4 1,14 2,21 2,28 3,16 3,24 3,125? _ 3 1! 5; HOLE B RE 1R RED mbsf 836B-1R 1 Graph c 1 Φ LKh. Structure Descriptin. i. 0.5] i. - IL I.r>i." m 1Sectin [ 2 ' 3 <?- Middle Pleistcene O O O i O O "* O ~L i O : Disturb Sample S S S S s s s Clr 10YR 3/3 'n7? H 10YR 5/3 10YR 6/2 10YR 5/3 CLAYEY NANNOFOSSIL MIXED SEDIMENT WITH GLASS, NANNO- FOSSIL VITRIC MIXED SEDIMENT WITH CLAY and VITRIC NANNO- FOSSIL MIXED SEDIMENT WITH CLAY Majr lithlgies: CLAYEY NANNO- FOSSIL MIXED SEDIMENT WITH GLASS and NANNOFOSSIL VITRIC MIXED SEDIMENT WITH CLAY, dark brwn (10YR 3/3) t brwn (10YR 5/3). VITRIC NANNOFOSSIL MIXED SEDIMENT WITH CLAY, brwn (10YR 5/3). Minr IKhlgy: VITRIC VOLCANIC SILT, light brwnish gray (10YR 6/2) ccurs in Sectin 2, cm, and in Sectin 3,19-28 cm and cm. WASHED mbsf tri

6 13583SB2R SMEAR SLIDE SUMMARY (%): HOLE B RE 2R RED mbsf 836B-2R D Meter Graphic Lith. Sectin <s> Structure Disturb Sample Clr Descriptin Clay Clay Feldspar L J. M 1 < > s CLAYEY NANNOFOSSIL MIXED SEDIMENT WITH GLASS Majr lithlgy: CLAYEY NANNOFOSSIL MIXED SEDIMENT WITH GLASS, dark brwn (10YR 3/3), slightly indurated, mttled sediment with sme mm-sized yellw intraclasts. E5.. """ ES" Minr lithlgy: Nne. ; HOLE B Meter 0.5; I.Oj Graphic Lith. 1Sectin Age *< > Λ < > Λ < > Λ < Λ.V Λ V. V Λ ; h<><><><?< > Λ < > Λ <?< ^< > Λ < > Λ < > Λ < 2?<?<?<?<?< > Λ < > Λ < >*< RE 3R Structure rt j Disturb > > Sample Clr 2.5Y 6\4 RED Descriptin VITRIC CLAYSTONE mbsf Majr lithlgy: VITRIC CLAYSTONE, light yellwish brwn (2.5Y 6/4) t light greenish gray (10Y 5/2). The sediment is mttled due t biturbatin and shws crss-laminatin and planarlaminatin. Graded layers ccur as well as pebbly intervals. Minr lithlgy: Nne. as " B n us 120 ES

7 A-3H-3 C/5 UNIT 1: APHYRIC BASALTIC GLASS GRAVEL cm 0 - Pieces 8-99 cm NTACTS: Nne. PHENOCRYSTS: Plagiclase: 1%-2%; <1 mm; euhedral. GROUNDMASS: Glassy. VESICLES: Cmmn, many fragment vesicular. LOR: Black. STRUCTURE: N/A. ALTERATION: Fresh. VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: A depsit f fresh, angular glass fragments. Preservatin f sharp edged cnchidal fractures indicates that this material has nt been transprted far (if at all) frm its surce. Fragments range in size frm <1 mm t 2 cm in length. Glassy basalt gravel Φ (carse fragments) 0 = Graded layers f black vlcanic sand 1J 879

8 <D A-3H-4 UNIT 2: APHYRIC BASALTIC GLASS GRAVEL cm 0-1 S g ü rx cn K "5" J= Pieces cm NTACTS: N/A. PHENOCRYSTS: Plagiclase: 1%-2%; <1 mm; euhedral. GROUNDMASS: Glassy. VESICLES: Cmmn, many fragments vesicular. LOR: Black. STRUCTURE: N/A. ALTERATION: Fresh. VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: A depsit f fresh, angular, basaltic glass. Excellent cnchidal fracturing is preserved, indicating that the fragments have been depsited very clse t their rigin. Fragments range frm <1 mm up t 1.5 cm in length. i # Bedded ash ^2> Pebbles f indurated ash //y ^ Glassy basalt gravel Carse glass fragments 1I

9 A-3H-CC i Piece 1 Glass ym Glass Indurated sediment UNIT 3: APHYRIC BASALT Piece 1 NTACTS: Nne, but cntains glass rinds n three sides. PHENOCRYSTS: Plagiclase: ace-1%; <1 mm; euhedral. Olivine: ace; <1 mm; subhedral. GROUNDMASS: Fine-grained, micrlitic t glassy. VESICLES: 0%-10%; <1 mm; rund-irregular; variable distributin; sulfides (and their alteratin prducts) ccur in vesicles clse t fractures. Vesicles absent in the glass but grade rapidly t abut 10% in the interir. LOR: Black, 2.5Y 2/0. STRUCTURE: Appears t represent part f a pillw. ALTERATION: Nne. VEINS/FRACTURES: 1%; small cracks; varius rientatins; sulfides ccur as a fine dusting clse t cracks; these are altered(?) t secndary blue-purple (azurite clred) material. 1J 881

10 A-4H-CC ö "B UNIT 3: APHYRIC BASALT Pieces 0-14 cm Icm 0 -i ICD O NTACTS: Nne. PHENOCRYSTS: Plagiclase visible nly in sme fragments. Plagiclase: <1%; up t 1.5 mm; glmerprphyritic aggregates. GROUNDMASS: Fine-grained t glassy. VESICLES: 0%-10%; up t 2 mm; runded; variable; sme fragments vesicular. LOR: Black. STRUCTURE: N/A. ALTERATION: Fresh t slightly altered. VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: Sme pieces (even chips nly a few millimeters acrss) have well develped glassy rinds. Drilling rubble. Basaltic glass and rck fragments 1 1

11 A-5X-1 UNIT 3: APHYRIC TO SPARSELY PHYRIC PLAGIOCLASE BASALT Pieces 1-11 cm NTACTS: Nne. PHENOCRYSTS: Plagiclase; 1%; <1 mm; euhedral. GROUNDMASS: Fine-grained micrcrystalline. VESICLES: 10%-20%; <0.5 mm and >1 mm; rund t irregular; variable distributin; the very fine vesicles are distributed unifrmly thrughut, larger vesicles frm pipes up t 4 cm in length. LOR: 10YR5/1 gray. STRUCTURE: Massive. ALTERATION: Fresh t slightly altered. VEINS/FRACTURES: Nne. 1I 883

12 cm 0 -i rr 03.0) δ α> T3 Q. ü UNIT 3: APHYRIC BASALT Pieces 0-10 cm A-6X-1 NTACTS: Tw igneus pebbles in drill rubble cmpsed largely f sedimentary clasts PHENOCRYSTS: Plagiclase: ace; 1 mm; euhedral. GROUNDMASS: Micrcrystalline. VESICLES: 25%; < 0.5 mm; irregular; thrughut. LOR: 7.5YR 5/0 gray. STRUCTURE: Pebbles. ALTERATION: Slight. VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: Drilling rubble. 1I 884

13 A-7X-1 cm 0 - Φ.Q E 2 ece Q_ ü raph CD ntat Φ CΛ Φ c rieniati O cö.q Q. *ç. UNIT 4: APHYRIC BASALT Pieces 1-8 NTACTS: Nne. PHENOCRYSTS: Nne visible. GROUNDMASS: Fine- t medium-grained, 2 mm lng phitic clinpyrxene crystals intergrwn with euhedral-anhedral plagiclases. Sme livine als nted. VESICLES: 0%-15%; <0.5 and >1 mm; rund-irregular; variable; Clrs vary frm clrless, white, yellw, range, brwn. Fine vesicles unifrmly distributed, larger nes are rare (eg. Pieces 1 and 8). Miarles: Nearly all small vesicles are filled with spectacular zelites including radiating acicular clusters, bladed and wrmy-glbular varieties. LOR: 7.5YR gray (fresh) t 10YR 5/1, gray. STRUCTURE: Massive. ALTERATION: Slightly t highly (Piece 6) altered; very sharply defined alteratin frnts. VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: Piece 2 cntains glassy fragments indicating a flw bundary. Yellw gray altered material 1I 885

14 A-8X-1 cm 0 -i Q_ 0 "P I 1 I = -9 CD c O 'σ> _ UNIT 4: APHYRIC BASALT Pieces 1-12 NTACTS: Nne. PHENOCRYSTS: Nne. GROUNDMASS: Subphitic plagiclase/augite intergrwth, rare livine(?). VESICLES: 8%-20%; 1-3 mm; irregular; increase tward bttm f sectin; irregular miarles in all pieces mm; larger, spherical vesicles widely scattered at tp f sectin. Miarles: Vesicle walls shw prjecting plagidase; vergrwth f zelites. LOR: 7.5YR 5/0, gray (fresh) t 10YR 5/2 yellw-gray (altered). STRUCTURE: Massive. ALTERATION: Fresh t mderately altered (lw-t xidatin). VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: Very sharp alteratin bundaries; cntrl nt bvius. Pieces 1 and 2 mre finely vesicular and finer grained than remaining fragments suggesting prximity t a flw tp. Piece 12 is distinctly diabasic in texture. 4A Altered (lw temperature xidatin) 4B t D 7A 7B 8A 8B I

15 jmber z. CD ü c aphic presentati c ientati CD T3 ipbardstu llgicunit UNIT 4: APHYRIC BASALT Pieces A-9X-1 cm 0 -i NTACTS: Nne. PHENOCRYSTS: Plagiclase phencrysts nt well-defined; grade int grundmass feldspar. Plagiclase: <1%; 1-2 mm; euhedral. GROUNDMASS: Fine- t medium-grained; hlcrystalline. Plagiclase dminant, plus clinpyrxene; seriate texture. VESICLES: 15%-20%; mm; runded t calescing; disseminated; higher cncentratins f larger vesicles in Pieces 1 and 2. Miarles: Linings f bluish-green encrusting zelites; additinal Fe-xide in vesicles in weathered zne. LOR: 10YR 4/1, dark gray. STRUCTURE: Massive. ALTERATION: Zne f brwn weathered and highly altered cre runs nearly vertically dwn ne edge f cre length; therwise mderately altered. VEINS/FRACTURES: Margin f Piece 1 is a fracture surface cated with yellw-brwn clay(?) and Fe-xide. ADDITIONAL MMENTS: Diabasic appearance. 3B Altered brwn basalt Strngly vesiculated-carser vesicles 1I 887

16 A-9X-2 cm 0-2g CD OC s CD Q. g O 1c UNIT 4: APHYRIC BASALT Pieces 1-4 NTACTS: Nne. PHENOCRYSTS: Plagiclase: ace-1%; mm; euhedral. GROUNDMASS: Fine- t medium-grained; micrcrystalline: plagiclase micrlites (t 1.2 mm, average abut 0.6 mm), intergranular t subphitic clinpyrxene, rare livine(?). VESICLES: 8%-12%; mm; rugh, irregular; randm distributin; large vesicles (arund 1 mm) slightly mre abundant in Piece 3. Miarles: Small zelite linings cmmn; altered znes in Pieces 1 t 4 have sme range t yellw-brwn clayey linings f vesicles. LOR: 7.5YR 6/0 gray (fresh) t 2.5YR 6/0 and 10YR 6/0 grays (altered). STRUCTURE: Massive. ALTERATION: Zelite vesicle linings in bth fresh and altered varieties; Pieces 1 t 3 and the tp crner f Piece 4 have the messtasis altered t a clay giving the rck a greenish brwn cast. Rck is mderately altered. VEINS/FRACTURES: ace; < 1 mm; near vertical near vertical; ne fracture break is Piece 2; its surface is cated with dark greenish brwn zelites and clays. ADDITIONAL MMENTS: Surface cating in Piece 6 f white irregular layer f zelite(?) next t basalt, then a patchy cating f yellw-range clay(?) sptted with Mn-xides. Weathered, brwnish basalt 1I

17 B-2R-1 cm 0 -i Q_ «l aò t I I 8-5 UNIT 3: SPARSELY PHYRIC PLAGIOCLASE BASALT Piece 2 NTACTS: Nne, but ne chip shws a textured surface cnsistent with a flw tp. PHENOCRYSTS: Plagiclase: 1%-2%; up t 2.5 mm; euhedral tabular crystals. GROUNDMASS: Fine-grained. VESICLES: 5%-10%; <0.5 and >1.5; rund t irregular; variable; sme lined with dark gray material (Mn-xide). LOR: 2.5Y 5/0, gray. STRUCTURE: Massive. ALTERATION: Fresh t slightly altered. VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: Tw small black fragments, and very fine-grained and vesicular, suggesting near flw tp material. Drilling rubble. 1 1

18 α5.q Num c "+-; atin CD _3 )ard UNIT 4A: APHYRIC BASALT Pieces B-3R-1 cm 0 CD 1 NTACTS: Piece 8 has a glassy rind and underlies the sediment interval, but n actual cntacts are bserved. PHENOCRYSTS: Plagiclase: ace; <1 mm; as quenched laths in the glass and mre rectangular euhedral crystals in the interir crystalline matrix. GROUNDMASS: Fine-grained intergrwth f plagiclase laths and clinpyr ene (large ikcrysts?). Rare yellwish glassy grains may be livine. VESICLES: 5%-15%; <0.5 mm and >1; rund t irregular; variable; estimates f vesicle cntent are almst meaningless wing t the high degree f zelite infilling. Small vesicles appear t be unifrmly distributed, while larger vesicles frm pipes and randmly distributed clusters. Miarles: Zelites fill mst vesicles. Varieties include cream white hexagnal plates, radiating white acicular crystals and blue-white glbules. White crystals appear Fe-stained in the mre altered areas. LOR: 2.5Y 5/0, gray (fresh) t 10YR 6/1, gray (altered). STRUCTURE: Massive. ALTERATION: Slight t high. Alteratin hals are sharply defined but are nt related t bvius fracturing. VEINS/FRACTURES: Nne. fife ODentes glassy rim Weathered t brwnish clr (fresh where nt hatchured) 1 890

19 B-3R-2 cm 0 -i CD ü CD b. c CD -.2 I; α> CD OC g. UNIT 4A: APHYRIC BASALT Pieces 1-18 NTACTS: Nne. PHENOCRYSTS: Plagiclase: ace; <1 mm; euhedral. GROUNDMASS: Fine-grained intergrwth f plagiclase laths and clinpyr ene ikcrysts(?). Rare glassy livines(?) VESICLES: 5%-15%; <0.5 and >1 mm; rund t irregular; randm distributin; estimates f vesicle percentages is largely meaningless wing t the high degree f zelite infilling. Smaller vesicles appear t be unifrmly distributed, while larger nes are rare and smetimes frm pipes. Miarles: Larger cavities are filled with a variety f zelites, including spectacular radiating acicular clusters. Mst vesicles are lined with zelites f sme descriptin (ie. blue-white, white, range). LOR: 2.5Y 5/0, gray (fresh) t 10YR 6/1, gray (altered). STRUCTURE: Massive. ALTERATION: Slight t mderate. VEINS/FRACTURES: <1%; <1 mm wide; steeply dipping; irregular surfaces are cated with Fe-xyhydrxides and Mn-xide. Altered, brwn basalt 50 H tfh Highly vesicular znes (Pieces 1 and 10B) 10A 10B A A 13B A 17B 1I

20 UNIT 4B: APHYRIC BASALT B-4R-1 cm 0 - Pieces 2-9 NTACTS: Nne. PHENOCRYSTS: Nne. GROUNDMASS: Fine-grained, euhedral plagiclase laths intergrwn with large clinpyrxenes (ikcrysts?). Pssible rare livines (yellwish, glassy grains). VESICLES: 5%-15%; <0.5 and >1 mm; rund t irregular; variable; the percentage f vesicles present is difficult t estimate wing t the large amunt f zelite infilling. Small vesicles are essentially unifrmly distributed; hwever, the larger vesicles are mre randmly scattered. Smetimes their distributin is higher in the mre altered yellwish hals, which may indicate that material has been leached ut. Miarles: Mst vesicles are filled with white t range zelites. LOR: 2.5YR 5/0, gray (fresh), t 10YR 6/1, gray (altered). STRUCTURE: Massive. ALTERATION: Generally mderate, sme patches are mre bluish gray and lk t be nly slightly altered. VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: This basalt lks the same as that in Cre B-3R. Therefre, despite the ccurrence f a sediment clast at the tp f this sectin, the unit has been called 4B rather than 5. Yellw gray alteratin 1I

21 cm 0 -i (1*1 \ ece Ni Q- 2A 2B raphic c ntati θ CD α> Q. ΦGC 'ientati t α> T3 Z3 T5 lipba c ü thlgi UNIT 4B : APHYRIC BASALT Pieces 1-5B B-5R-1 NTACTS: Nne; ne chip in Piece 1 shws a 2 mm thick glassy rim. PHENOCRYSTS: Nne visible. GROUNDMASS: Fine-grained plagiclase laths intergrwn with clinpyrxene grains and rare livine. VESICLES: 5%-15%; <0.5 and >1.0 mm; rund t irregular; randm distributin; fine vesicles are distributed unifrmly thrughut the rck. The larger vesicles tend t be distributed in patches. Miarles: Mst vesicles are devid f infilling, hwever white hexagnal plates and lng, acicular zelites are cmmnly bserved. LOR: 2.5Y 4/0, gray. STRUCTURE: Massive. ALTERATION: Fresh t slightly altered (Piece 1 has alteratin hals n tw sides) up t mderately altered. VEINS/FRACTURES: <1%; <1 mm wide; subhrizntal; clear, irregular surfaces; pssibly brken during drilling. ADDITIONAL MMENTS: Pssibly slightly carser grained cmpared with samples frm higher in the hle. 50 f v ü 5A 5B 1I 893

22 CD T B-5R-2 cm 0 -i E Z> CD 1A CD CC p cö en UNIT 4B: APHYRIC BASALT Pieces 1A-3B NTACTS: Nne visible. PHENOCRYSTS: Nne. GROUNDMASS: Fine-grained; euhedral plagiclase intergrwn with clinpyrxene and rare livine. VESICLES: 5%-15%; <0.5 and up t 4 mm; rund t irregular; randm distributin; small vesicles are unifrmly distributed. Large cavities are mre patchy in their distributin and may frm lng pipes (ie. ver 10 cm lng; see back f Piece 1B). Miarles: Relatively clear vesicles, ccasinally spectacular radiating acicular zelites, thers include range glbular and white wrmy zelites. LOR: 2.5Y 4/0, gray. STRUCTURE: Massive. ALTERATION: Generally fresh t slightly altered; alteratin hals n Pieces 3A and 3B tend t be mderately altered. VEINS/FRACTURES: <1%; <1 mm wide; steeply dipping; The fracture between Pieces 1A and 1B is irregular and clean. That dividing Pieces 3A and 3B is sptted with Fe-xyhydrxides and an alteratin hal extends fr 1.5 t 2 cm n either side f the break. 1B CD 3A _ Alteratin frnt adjacent t fracture 3B 1J 894

23 B-5R-3 cm 0 -i ö 1A 1B is CD DC re δ s O -g O Q. UNIT 4B: APHYRIC BASALT Pieces 1B-8 NTACTS: Nne visible. PHENOCRYSTS: Nne visible. GROUNDMASS: Fine-grained interlcking lath shaped plagiclase and dinpyrxene with rare livine. VESICLES: 5%-15%; <0.5 and >1 mm; rund t irregular; randm distributin; small vesicles are dminant and appear t be unifrmly distributed. Larger vesicles are mre dminant in the mre altered areas. Miarles: A large cavity in Piece 1A (8 mm diameter) is filled with a spectacular set f radiating clrless zelites. Small range, red, white zelites als bserved in smaller vesicles. LOR: 2.5Y 4/0, gray t 10YR 6/1, gray (altered). STRUCTURE: Massive. ALTERATION: Fresh t mderately altered. VEINS/FRACTURES: <1%; <1 mm wide; randm rientatins; generally assciated with wide (2-4 cm) wide alteratin hals. Cated with range- brwn Fe-xyhydrxides and acicular, clrless zelites. / 'A Yelwish brwn alteratin frnt 1I 895

24 B-5R-4 cm 0 -i E z CD KCD 1A 1B ntati ^ ü rr g Φ δ Z3 rdsi 03 O JD Q. ü σ UNIT 4B: APHYRIC BASALT Pieces 1A-1B NTACTS: Nne visible. PHENOCRYSTS: Nne visible. GROUNDMASS: Fine-grained, interlcking euhedral plagiclase with clinpyr ene and rare livine. VESICLES: 5%-15%; <0.5 and >1.0 mm; rund t irregular; randm distributin; small vesicles are unifrmly distribute. Larger vesicles ccur in patches (see abve). Mst have at least sme zelite infill. Miarles: Large calesced vesicles frm cavities up t 2 cm lng which are parts f pipe features. These are filled with white radiating acicular zelites as well as black glbular and range-brwn zelites. LOR: 2.5Y 4/0, gray (fresh) t 10YR 6/1, gray (altered). STRUCTURE: Massive. ALTERATION: Slightly t mderately altered VEINS/FRACTURES: One edge f Piece 1A appears t be an ld fracture. It cntains Fe-xyhydrxides n its surface. V Yellwish brwn altered basalt Highly vesicular znes f zelites filling large vesicles 1I 896

25 Φ B-6R-1 cm 0 -i 2A.2 g Q C3 CC "O r g. UNIT 4B: APHYRIC BASALT Pieces 1-7 NTACTS: Nne visible. PHENOCRYSTS: Nne visible. GROUNDMASS: Interlcking plagiclase and clinpyrxene with rare livine (subphitic). Plagiclase is tabular, subhedral; clinpyrxene is anhedral. VESICLES: 5%-15%; mm; subrunded; randm distributin; tend t be aligned parallel t fracture in Pieces 2A t 2D. Miarles: Irregular cavities 0.02 t 0.05 mm diameter; tend t be partly r cmpletely filled by zelite. LOR: 2.5Y 4/0, gray (fresh) t 10YR 6/1, gray (altered). STRUCTURE: Massive. ALTERATION: Mst intense in Piece 1; alteratin bundary parallels fracture. Mst f rck is slightly t mderately altered. VEINS/FRACTURES: <1%; 20 cm; vertical; vein cated with zelite; gray dense zne abut cm wide adjacent t fracture, pssibly silicified. ADDITIONAL MMENTS: Alteratin cnsists f xidatin and depsitin f Fe-xides in vesicles; plagiclase becmes chalky. Alteratin/xidatin 6A 6B 6C

26 B-6R-2 cm 0 -i 8 Φ Q_ 1A ü rr c Φ δ σ r.q g.!π C5> UNIT 4B: APHYRIC BASALT Pieces 1A-1D NTACTS: See cmments. PHENOCRYSTS: Nne visible. GROUNDMASS: Dminantly intergrwn plagiclase and clinpyrxene with minr livine. VESICLES: 1%-10%; mm; subrunded; randm distributin. Miarles: Irregular cavities mm merge with vesicles. LOR: 2.5YR 5/2, yellw-gray when altered; dark blue-gray when fresh. STRUCTURE: Massive. ALTERATION: Slightly t mderately altered, mst intense in 6 cm area at the bttm f Piece 1D. VEINS/FRACTURES: 2%; 55 mm wide; near vertical rientatin; this is an internal flw cntact, quenched n ne side, and with defrmed quenched bundaries n bth sides f lwer part f bundary zne. ADDITIONAL MMENTS: Alteratin at bttm f Piece 1D appears t be frm lw T xidatin, as at tp f B-6R-1. 1B JjU 1C 1D Piece 1C (quenched Internal flw bundary) 1 1

27 cm 0 -i α5 E -7 iece [ Q- raphi epres c g Φ rr g -i ' rientc O wφ TD "D hipb UNIT 4B: APHYRIC BASALT Pieces B-7R-1 NTACTS: Bttm f Unit 4. PHENOCRYSTS: N clearly defined phencrysts visible - nte seriate texture with sme crystals near phencrystal size. GROUNDMASS: Fine-grained interlcking netwrk f plagiclase and clinpyrxene; rare euhedral livine; seriate, hlcrystalline, subphitic. VESICLES: 10% 15%; mm; runded t calescive; ccur thrughut; These tw pieces f Unit 4 are at the base f Unit 4. They are significantly less vesicular than any f the verlying prtins f Unit 4. Bth vesicle size and vesicle distributin is less. Largest vesicles are spradically distributed and relatively scarce. Miarles: Mst are partially filled with acicular t glbular zelites f varius clrs; sme Fe-xide and Mn-xide catings. LOR: 2.5Y6/2 gray. STRUCTURE: Massive. ALTERATION: Mderate; slightly weathered (lw-temperature alteratin). VEINS/FRACTURES: Nne. ADDITIONAL MMENTS: There is a prminent banding acrss Piece 1, but it is prbably due t differential alteratin. UNIT 5: MODERATELY PHYRIC PLAGIOCLASE BASALT CLINOPYROXENE Pieces 3-20 NTACTS: Very fine t "glassy" btryidal surface n Piece 9 has sediment embedded in cavities; relict (altered) glassy rim n Piece 4. PHENOCRYSTS: Plagiclase: 1%-2%; <2.0 mm; fine laths. Olivine: 1%-2%; <2.0 mm; subhedral t anhedral grains. Clinpyrxene: 1%-2%; <2.0 mm; anhedral, islated grains. GROUNDMASS: Fine-grained. VESICLES: 25%-30%; <0.1 t 6 mm; rund t irregular; unifrm distributin; mst vesicles are relatively clear f infilling. Piece 7 has a large vid with yellw-green clays. Piece 5 als shws Fe-xyhydrxide fillings. LOR: 2.5Y 3/0, dark gray. STRUCTURE: Massive. ALTERATION: Fresh t slightly altered. VEINS/FRACTURES: Nne. Q9 Highly vesicular zne (lcal) ^ Relict glassy margin (altered) ; & Very vesicular samples (thrughut)

28 B-7R-2 σ UNIT 5: SPARSELY TO MODERATELY PHYRIC CLINOPYROXENE PLAGIOCLASE BASALT cm 0-2 g Pieces 1-9 NTACTS: Nne visible. PHENOCRYSTS: Plagiclase: 1%-2%; <2.0 mm; elngate laths. Olivine: ace-1%; <1.5 mm; anhedral grains. Clinpyrxene: 1%-2%; <2.0 mm; anhedral, islated grains. GROUNDMASS: Fine-grained. VESICLES: 25%-30%; <0.1 t 4 mm; rund t irregular; unifrm distributin; larger vesicles (>2 mm) are rare but randmly distributed and empty. LOR: 2.5Y 3/0, dark gray. STRUCTURE: Massive. ALTERATION: Fresh t slightly altered. VEINS/FRACTURES: Piece 1 has a very irregular side which may be a fracture surface. There are green and yellw-range clays in the depressins alng this side. ID O CD O 1I 900

29 Φ T B-8R-1 cm 0 -i II CD CC p cö.d g_ In 3 ü CD O O UNIT 5: SPARSELY TO MODERATELY PHYRIC CLINOPYROXENE PLAGIOCLASE BASALT Pieces 1-12 NTACTS: Nne. PHENOCRYSTS: Plagiclase: 1%-2%; up t 2.0 mm; euhedral tabular crystals. Olivine: ace-1%; up t 1.5 mm; euhedral t subhedral crystals. Clinpyr ene: 1%-2%; up t 1.5 mm; anhedral, islated grains. GROUNDMASS: Seriate, hlcrystalline, subphitic. Plagiclase and subrdinate pyrxene visible. VESICLES: 25%-30%; 0.1 t 7.0 mm; runded t calescing; disseminated; largest vesicles spradically distributed and relatively scarce. Miarles: Very rare yellwish brwn and brwn clay and Fe-xide linings. LOR: 2.5YR 4/0 dark gray. STRUCTURE: Massive. ALTERATION: Fresh t slight. VEINS/FRACTURES: N veins seen. t RE/SECTION 901

30 B-9M-1 cm 0 - re I D re.q Q.!c en UNIT 5: SPARSELY TO MODERATELY PHYRIC CLINOPYROXENE PLAGIOCLASE BASALT Pieces 1-16 NTACTS: Glassy rind n Piece 13. PHENOCRYSTS: Olivine crystals tend t ccur in lcalized grupings f phencrysts (nt as glmercrysts). Plagiclase: 1%-2%; up t 2 mm; euhedral tabular crystals. Olivine: ace-1%; up t 1.5 mm; euhedral t subhedral islated crystals. Clinpyrxene: 1%-2%; up t 1.5 mm; subhedral t anhedral. GROUNDMASS: Very fine-grained. VESICLES: 25%-40%; 0.1 t 7.0 mm; runded t calescive; disseminated; carsest vesicles ccur mre cmmnly in Pieces 2 and 5. Miarles: Rare infillings and linings f yellw-brwn and brwn clays(?) and Fe-xides. LOR: 2.5YR 5/0 gray. STRUCTURE: Massive. ALTERATION: Nne t slight. VEINS/FRACTURES: Nne visible. ADDITIONAL MMENTS: Cre has n stratigraphic significance as the drill bit did nt advance. carse 'y vesicular than ther fragments a u D 1I 902

31 A-3H-04 (85 cm) ROCK NAME: Aphyric basaltic glass GRAIN SIZE: Nne OBSERVER: KRI WHERE SAMPLED: Unit 2 TEXTURE: Glassy, sparsely micrphencrystal PRIMARY MINERALOGY PERCENT PERCENT SIZE PRESENT ORIGINAL (mm) MPO- SITION MORPHOLOGY PHENOCRYSTS Plagiclase <l Clinpyrxene <l Orthpyrxene <l <l <l euhedral euhedral t subhedral quench textures, sdic rims cmmn quench textures, sme in small glmercrystic clusters with plagiclase, many with grwth imperfectins lath shaped GROUNDMASS Tan glass 60 n/a n / a extremely fresh t spherulitic VESICLES/ CAVITIES Vesicles SIZE PERCENT LOCATION (mm) 40 ccur <1.4 mm thrughut FILLING rare paque glbular infillings SHAPE runded MMENTS the largest vesicles are clearly the result f several smaller nes calescing; in sme fragments vesicles are very elngate; the fillings culd be Mn-xides r gethite This sectin was made frm pieces f a basaltic gravel layer. It includes six 1 cm fragments. The abve descriptin is an average ver all f the pieces. Textures range frm glassy t spherulitic. An 1121 pint cunt gives: 57.9% glassy messtasis, 41% vesicles, 0.5% plagiclase phencrysts, 0.3% clinpyrxene and 0.3% rthpyrxene phencrysts. Micrphencrysts (<0.1%) f magnetite are als present. The cunt was an average ver all f the pieces. The pyrxene phencrysts cnsist f bth clinpyrxene and rthpyrxene (nte green-brwn plechrism, straight extinctin, and high 2V). Sme crystals cntain clinpyrxene-rthpyrxene intergrwths. 903

32 A-5X-01 (Piece 1,0-11 cm) OBSERVER: SHE WHERE SAMPLED: Unit 3 ROCK NAME: Sparsely phyric livine-plagiclase basalt GRAIN SIZE: Fine grained t varilitic TEXTURE: Vesicular, seriate prphyritic PRIMARY MINERALOGY PERCENT PERCENT SIZE PRESENT ORIGINAL (mm) MPO- SITION MORPHOLOGY PHENOCRYSTS Plagiclase An68 tr GROUNDMASS Plagiclase < An65-( Clinpyrxene <O Olivine < Opaques <O.Ol Spinel tr tr euhedral t anhedral euhedral t skeletal euhedral t subhedral anhedral euhedral t subhedral subhedral euhedral t subhedral blcky, tabular crystals; largest appear partly resrbed; at least sme with mre sdic rims single crystals and intergrwn with plagilcase lng laths intergrwn with livine and in bundles with clinpyrxene; zning cmmn; serve as nucleatin sites fr quench clinpyrxenes intergrwn with plagiclase, quench mrphlgies cmmn; grades int quench crystllites included in messtasis intergrwn with plagiclase and as single crystals disseminated in grundmass; all magnetite included in plagiclase SENDARY REPLACING/ MINERALOGY PERCENT FILLING Green clay 2 vesicle linings red-brwn 1 vesicle linings hematite? MMENTS linign vesicles alng a distinct band r a hematite-stained clay?; ccurs as a filling n tp f the green clay VESICLES/ SIZE CAVITIES PERCENT LOCATION (mm) Vesicles thrughut FILLING partial linings in sme SHAPE vid (large) t irregular (small) MMENTS largest (>0.4 mm) cncentrated in areas with dark quench fill; largest als smetimes in elngate patches almst frming cavities; smaller nes smetimes calesce t frm larger nes Messtasis is 30-35% and maybe 1-2% altered. The grundmass has a seriate texture f calescing plagiclase bundles intergrwn with clinpyrxene and livine. Vesicular with a large amunt f fresh grundmass frmed by clinpyrxene-plagiclase-magnetite crystallites. There are dicrete patches f darker quench material (aphyric, few micrlites, carsely vesicular) as patches (4-6 mm acrss), linings t vesicles, and as a band cutting acrss the sample. Clay linings in vesicles are cncentrated alng distinct lines, ne f which is als a zne characterized by large vesicles pint cunt gives: Messtasis (includes sme cpx crystallites) 32.1%; Plagiclase grundmass 22.3%; Clinpyrxene grundmass 19.4%; Olivine grundmass 1.5%; Opaques 3.9%; Plagiclase phencrysts 1.4%; Olivine phencrysts 0.4%; Open vesicles 18.2%; Filled vesicles 0.8%; Ttal vesicles

33 A-7X-01 (Piece 4,42-43 cm) OBSERVER: EWE WHERE SAMPLED: Unit 4 ROCK NAME: Aphyric basalt GRAIN SIZE: Fine grained TEXTURE: Vesicular, phitic, diabasic PRIMARY PERCENT PERCENT SIZE MPO- MINERALOGY PRESENT ORIGINAL (mm) SITION Plagiclase An60-65 Clinpyrxene 20 Olivine 2-3 Magnetite 2-3 Messtasis up t n/a MORPHOLOGY euhedral t subhedral subhedral t anhedral anhedral subhedral t anhedral interstitial MMENTS elngated laths, nrmally zned; interlcking msaic, intergrwn with pyrxene and livne phitic t pikilitic; zned interstitial with intergrwn and included plagiclase mstly interstitial; sme skeletal micrcrystalline, intersertal, with fibrus grwths and micrspherulitic aggregates; largely altered pssibly t (r with) fine fibrus actinlite SENDARY MINERALOGY PERCENT Aragnite 1-2 chlrite/actin lite Fe-xyhydrxide tr REPLACING/ FILLING vesicle filling vesicle filing, messtasis replacement vesicle linings MMENTS erratically distributed dminant alteratin prduct VESICLES/ SIZE CAVITIES PERCENT LOCATION (mm) Vesicles evenly up t 2 distributed FILLING cmplete t partial SHAPE MMENTS subrunded mstly filled by t secndary minerals intercnnected aces f dark brwn Cr-spinel ccur included in plagiclase laths. Spinels are euhedral grains, abut 0.03 mm in size. In spite f extensive vesicle infilling and alteratin f messtasis the primary mineral phases are very fresh. Cntinuus variatins f grain size typify the texture, with n bvius phencrystal grains. The messtasis alteratin prduct has been termed fine-grained clay aggregates by SHE in ther slides frm this unit. Rck is mderately altered. 905

34 A-9X-02 (Piece 4,45-47 cm) OBSERVER: JAN WHERE SAMPLED: Unit 4 ROCK NAME: Aphyric basalt GRAIN SIZE: Fine grained TEXTURE: Vesicular, diabasic PRIMARY MINERALOGY PERCENT PERCENT PRESENT ORIGINAL SIZE (mm) MPO- SITION MORPHOLOGY PHENOCRYSTS Plagiclase large, blcky crystals rather than lng laths; zned GROUNDMASS Plagiclase Clinpyrxene Opaque Olivine? Messtasis tr 0-1 tr 0.1 mm 15 n/a subhedral subhedral t anhedral irregular anhedral interstital sme as lng as phencrysts but narri laths rather than euhedral phencryts undulse extinctin cmmn sme rd-like crystals in the messtasis, mainly irregular blbs cryptcrystalline; almst cmpletely altered t clays SENDARY REPLACING/ MINERALOGY PERCENT FILLING Greenish-brwn replacing messtasis and plagiclase clays VESICLES/ CAVITIES Vesicles PERCENT LOCATION thrughut SIZE (mm) FILLING n fillings SHAPE irregularly shaped MMENTS: Appears t be sme incipient breakdwn f plagiclase; the rck is mderately altered. A 1057 pint cunt gives 18.2% messtasis, 35% grundmass plagiclase, 23.0% grundmass clinpyrxene, 2.2% grundmass livine, 2.1% grundmass paques, 16.3% pen vesicles, 2.6% filled vesicles, 0.3% plagiclase phencrysts, 0.3% clinpyrxene phencrysts, 0.1% livine phencrysts. Phencrysts were defined n the basis f shape and relative size. 906

35 B-2R-01 (Piece 2,14-16 cm) OBSERVER: EWE WHERE SAMPLED: Unit 3 ROCK NAME: Mderately phyric livine -plagiclase basalt GRAIN SIZE: Fine grained TEXTURE: Prphyritic PRIMARY MINERALOGY PERCENT PERCENT SIZE PRESENT ORIGINAL (mm) MPO- SITION MORPHOLOGY PHENOCRYSTS Plagiclase Olivine ! euhedral t subhedral euhedral t subhedral elngated laths, mstly in glmerprphyritic aggregates; narrw mre sdic rims; sme f the larger angular grains may be xencrysts islated crystals, 'sme skeletal GROUNDMASS Plagiclase Olivine Cr-spinel Messtasis up t 0.1 An tr 1-2 up t 0.1 tr n/a euhedral t subhedral subhedral euhedral micrphencrysts interstitial laths t micrlites; many in skeletal and swallwtail frms mstly islated crystlals in grundmass and partly included in livine; dark brwn skeletal quench textures plus clinpyrxene-plagiclase intergrwths plus many very fine cmplex magnetite granular aggregates SENDARY MINERALOGY Red-range hematite PERCENT tr REPLACING/ FILLING lining vesicles red/green clays tr lining vesicles MMENTS culd be hematite/clay aggregates, ccur in ne crner f the slide lining and perhpas filling sme small vesicles; may als have replaced a bit f the grundmass; nt cmmn VESICLES/ CAVITIES Vesicles SIZE PERCENT LOCATION (mm) disseminated FILLING nne SHAPE subrunded t calescing MMENTS larger vesicles erratically distributed MMENTS: Very nice, fresh sample. Phencryst definitin fr pint cunt was smewhat subjective and accunts fr the difference in estimates. Ttal livine cntent is 2.3%, but all culd be cnsidered phencrysts, plagiclase is seriate making distinctin between phencrysts and grundmass rather arbitrary. This accunts fr difference between hand sample and thin sectin descriptins and names pint cunt gives: Messtasis (includes sme cpx crystallites) 66.7%; Open vesicles 14.2%; Filled vesicles 0.2%; Plagiclase grundmass 12.1%; Clinpyrxene grundmass 0.8%; Olivine grundmass 1.5%; Opaques 1.8%; Plagiclase phencrysts 1.8%; Olivine phencrysts 0.8%; Other (alteratin) 0.1%. 907

36 B-3R-01 (Piece 11,68-70 cm) OBSERVER: SHE WHERE SAMPLED: Unit 4 ROCK NAME: Sparsely phyric plagiclase basalt GRAIN SIZE: Fine grained TEXTURE: Vesicular, subphitic, intersertal PRIMARY MINERALOGY PERCENT PERCENT SIZE PRESENT ORIGINAL (mm) MPO- SITION MORPHOLOGY PHENOCRYSTS Plagiclase subhedral t anhedral sme partially runded; tabular, equant crystals with scillatry zning GROUNDMASS Plagiclase Clinpyrxene Olivine Opaques Messtasis < An50-60? < <O magnetite n/a euhedral t anhedral anhedral subhedral t anhedral subhedral t anhedral interstitial laths partially enclsed in clinpyrxene and altered messtasis subphitic t granular; zning, particularly sectr zning, is cmmn small grains, islated in grundmass cmmnly intergranular; skeletal frms cmmn largely altered t clays; may be sme pyrxene crystallites left SENDARY MINERALOGY Aragnite Brwnish clays REPLACING/ PERCENT FILLING 1-2 replacing messtasis, filling vesicles replacing messtasis MMENTS aggregates up t 0.1 t 0.5 mm fine-grained aggregates replacing messtasis; sme may be vesicle fill but it is hard t separate frm altered grundmass VESICLES/ SIZE CAVITIES PERCENT LOCATION (mm) Vesicles thrughut FILLING partially with clays SHAPE irregular t runded MMENTS largest may frm by calescence f smaller nes MMENTS: Sectin is thin and rather badly plucked; rare sulfide (?) in grundmass and edge f sme vesicles. Rck is mderately altered. 908

37 B-3R-02 (Piece 5,32-38 cm) OBSERVER: SHE WHERE SAMPLED: Unit 4 ROCK NAME: Aphyric basalt GRAIN SIZE: Fine t medium grained TEXTURE: Vesicular, phitic, intersertal PRIMARY MINERALOGY Plagiclase Clinpyrxene Olivine Opaques Messtasis SENDARY MINERALOGY Brwn clays Aragnite PERCENT PERCENT SIZE MPO- PRESENT ORIGINAL (mm) SITION < An < n/a 15 REPLACING/ PERCENT FILLING replacing grundmass tr-1 filling vesicles, relacing grundmass MORPHOLOGY anhedral t euhedral anhedral euhedral t subhedral euhedral t anhedral interstitial MMENTS zned laths enclsed in clinpyrxene r by messtasis phitic, sectr zned single crystals in grundmass interstitial magnetite replaced by clays MMENTS clearly partially filling grundmass als; in fine-grained radial t fibrus aggregates; sme replacement f livine alng fractures crystals t 0.5 mm ccur in granular aggregates and fanned bundles f blades; aggregates up t 1.5 mm; largely filling prsity; prbably sme grundmass and livine replacement t, but hard t tell VESICLES/ SIZE CAVITIES PERCENT LOCATION (mm) Vesicles thrughut 0.1 t 1 FILLING clays SHAPE irregular MMENTS may be significant filling f vesicles by clay but it is hard t tell frm grundmass alteratin MMENTS: Rck is mderately t highly altered. 909

38 B-3R-02 (Piece 13,93-94 cm) ROCK NAME: Aphyric basalt GRAIN SIZE: Fine grained OBSERVER: EWE WHERE SAMPLED: Unit 4 TEXTURE: Vesicular, subphitic t intergranular and intersertal PRIMARY PERCENT PERCENT SIZE MPO- MINERALOGY PRESENT ORIGINAL (mm) SITION Plagiclase An60-65 Clinpyrxene Magnetite Messtasis i n/a MORPHOLOGY euhedral t subhedral subhedral t anhedral subhedral t anhedral subhedral t anhedral interstitial MMENTS elngated laths, nrmally zned, interlcking and partially enclsed by clinpyrxene intergranular t subphitic; marked zning including hur glass structure, thugh cre t rim zning is mst cmmn frequently interstitial with included plagiclase laths and as islated crystals in grundmass; can be hard t differentiate frm clinpyrxene mainly interstitial, sme skeletal grains; in messtasis sme very small (<O.Ol mm) rd-like aggregates macrcrystalline chlrite/actinlite fibrus grwths plus clrless zelite (?); main alteratin culd als be fine-grained clay aggregates SENDARY REPLACING/ MINERALOGY PERCENT FILLING Chlrite/actin infilling and linings lite? Zelite <l Fe-xyhydrxide <l s Mixed 1 chlrite/clay? Aragnite tr lining vesicles infilling linings infilling MMENTS replacing messtasis and infilling vesicles; very fine aggregates; SHE has these dwn as brwn clays in radial fine-grained aggregates; prprtin f replacement vs. vesicle fill is hard t determine fine glbular grwths, n tp f clay/chlrite grwths, grwing int vesicles red-brwn znes in chlrite/actinlite/clay? aggregates fibrus t radiating greenish-brwn aggregates in vesicles VESICLES/ SIZE CAVITIES PERCENT LOCATION (mm) Vesicles evenly 0.15 t 2 distributed FILLING partial t cmplete SHAPE MMENTS subrunded mst cmmn size is 0.4 t t 1 mm; many have irregular quench linings; linings are clays and a hematitic material MMENTS: Primary minerals are very fresh in spite f extent f messtasis alteratin and vesicle infilling. Cntinuus variatins f grain size with n bvius phencrystal grains. There are trace sulfides, at least tw types, in the grundmass. The dark brwn t black grundmass lks like unaltered devitrified messtasis n first glance but is clearly replaced by small, radial aggregates f clays/actinlite/chlrite. Rck is mderately altered. 910

39 B-5R-02 (Piece 2,92-93 cm) OBSERVER: KRI WHERE SAMPLED: Unit 4 ROCK NAME: Aphyric basalt GRAIN SIZE: Medium grained TEXTURE: Vesicular, diabasic PRIMARY MINERALOGY PERCENT PERCENT SIZE PRESENT ORIGINAL (mm) MPO- SITION MORPHOLOGY PHENOCRYSTS Plagiclase equant t tabular grains; mre equant than grundmass; sme evidence f incipient alteratin; cmmnly zned GROUNDMASS Plagiclase Clinpyrxene Olivine Magnetite Messtasis <0.8 mm < < < n/a euhedral subhedral t anhedral anhedral equant, skeletal interstitial elngate laths t tabular grians, zned subphitic and interstitial identificatin is difficult but these are very clear with high interference clrs crucifrm grains cmmn, trace ilmenite lamellae in sme replaced by extremely fine grained green-brwn clays SENDARY MINERALOGY Zelites Mixed clays calcite REPLACING/ PERCENT FILLING <l filling vesicle walls replacing messtasis tr filling vesicles MMENTS rare, radiating zelites n sme vesicle margins messtasis is extensviely replaced by fine-grained green-brwn clays rare vesicle infillings VESICLES/ SIZE CAVITIES PERCENT LOCATION (mm) Vesicles thrughut 3 mm t FILLING minr SHAPE irregular MMENTS large, irregular shaped rds as well as small, intergranular vids; the large vids may in part be a prduct f plucking The slide is badly plucked thrughut. Many f the riginal vids have been enlarged and a lt f fine material depsited in the vesicles and veins may be frm the breaking and plucking. The vesicle percentages are therefre maximum estimates. A 787 pint cunt (aviding the wrst plucked areas) gave: 16.: messtasis, 0.9% plagiclase phencrysts (larger, blckier grains), 33.3% grundmass plagiclase, 17.8% grundmass clinpyrxene, 1.7% grundmass livine, 1.1% grundmass paques, 27.4% pen vesicles and 1.5% filled vesicles. Rck is mderately altered. 911

40 B-6R-02 (Piece 1C,59-63 cm) OBSERVER: EWE WHERE SAMPLED: Unit ROCK NAME: Mderately t highly phyric clinpyrxene-livine-plagiclase basalt GRAIN SIZE: Fine grained TEXTURE: Prphyritic, vesicular PRIMARY PERCENT PERCENT SIZE MINERALOGY PRESENT ORIGINAL (mm) MPO- SITION MORPHOLOGY PHENOCRYSTS Plagiclase Olivine Clinpyrxene <l <l Cr-spinel tr tr 0.05 euhedral t subhedral euhedral t subhedral subhedral t anhedral euhedral sme are zned with sdic rims islated crystals, sme with large inclusins partly intergrwn with plaigclase nt as a phencryst phase but n rm in grundmass field; as inclusins in plagiclase phencrysts; have narrw magnetite rims pssibly develped as the result f mixing; very rare and dark brwn GROUNDMASS Plagiclase Olivine Clinpyrxene Magnetite Sulfides up t t up t <l <l euhedral t anhedral euhedral t subhedral subhedral t anhedral euhedral t anhedral subhedral t anhedral tabular micrlites and micrphencrysts t anhedral messtasis grains mst islated grains; sme intergrwn in plagiclase mstly in granular messtasis varies frm discrete graines t interstitial grains ccurs as interstitial grundmass grains and adjacent t, r in, vesicles SENDARY MINERALOGY Clays REPLACING/ PERCENT FILLING 10 filling vesicles tr-1 filling vesicles MMENTS vesicles shw beautiful znatin frm brwn and pale green clays t apple-green clays fllwed by Fe-xyhyrdxides (?) tward the center f the vid. A few are cmpletely infilled, thers still shw vid space. clrless acicular zelites fill center f many vesicles; sulfides als assciated with vesicle margins. VESICLES/ CAVITIES Vesicles SIZE PERCENT LOCATION (mm) 10 randmly distributed Fractures <l crsscutting 0.1 mm wide FILLING partial t cmplete partially infilled SHAPE irregularly shaped MMENTS brwnish-green fibrus infillings; als deep green-brwn fibrus material (plechric); als acicular zelites This rck is fine-grained but the grundmass has a granular, near granblastic texture, with carser and finer grained intimately intermixed patches, apparently the result f internal magma mixing in the flw when the crystallizatin was incmplete. This mixing presumably als accunts fr the granular texture reminiscent f recrystallizatin textures. Finer grained lithlgy may be slightly pyrxene richer. Embedded in this granular grundmass are phencrysts and micrphencryst sized and mainly euhedral t subhedral plagiclase, livine, and minr clinpyrxene. The distinctin in size between phencrysts and micrphencrysts is arbitrary. Nevertheless, the cntrasting size and shape f these crystals, cmpared t the granular grundmass, gives the rck a distinctly prphyritic texture. Sulfide grains are relatively abundant. Mst appear t be assciated with vesicles, althugh nt necesarily inside the vesicle infillings. Other grains mre rarely ccur as interstitial grains. 912

41 B-7R-01 (Piece 6,31-32 cm) OBSERVER: SHE WHERE SAMPLED: Unit 5 ROCK NAME: Mderately phyric clinpyrxene-plagiclase basalt GRAIN SIZE: Aphanitic t fine grained TEXTURE: Vesicular, seriate prphyritic, subphitic PRIMARY MINERALOGY PERCENT PERCENT SIZE PRESENT ORIGINAL (mm) MPO- SITION MORPHOLOGY PHENOCRYSTS Plagiclase Clinpyrxene Olivine tr tr 0.1 anhedral t euhedral anhedral t subhedral euhedral mst in glmercrysts with r withut clinpyrxene; smaller grains ccur individually; glass inclusins ccur but nt cmmn; a few are anhedral and resrbed; phencrysts are equant, tabular crystals; bth reverse and nrmal zning in larger grains mst cmmnly subphitically intergrwn with plagiclase; als intergranular t plagiclase single crystals near glmercrysts GROUNDMASS Plagiclase Clinpyrxene Olivine? Opaques Messtasis t 0.1 mm tr tr n/a euhedral t skeletal subhedral, sheaves anhedral anhedral t skeletal n/a lng, skinny laths and quench mrphlgies 1-3% well-crystallized equant, anhedral grains; much f the grundmass cntains sheaflike quench clinpyrxenes single crystals in grundmass, identificatin uncertain disseminated thrughut grundmass; appear t be magnetite cmmn quench mrphlgies f plagiclase-pyrxene sheaves with disseminated paques; slight alteratin SENDARY REPLACING/ MINERALOGY PERCENT FILLING Hematite/clays 1-2 replacing grundmass, vesicle linings MMENTS ccur in vesicle edges and as patches in the grundmass; these patches have a slight reddish t greenish-yellw tinge; prbably incipient alteratin f messtasis t clays and hematite VESICLES/ SIZE CAVITIES PERCENT LOCATION (mm) Vesicles thrughut 0.1 t 5.0 FILLING nne SHAPE irregular MMENTS smaller nes runded; mst are irregular; the largest nes (3x5 mm) usually elngate The larger pyrxenes are nt uncmmnly curved with undulse extinctin. Plagiclase and pyrxene typically in glmercrysts f 2 t 15 grains; glmercrysts tend t be clumped tgether in prtins f the slide. There are unusual gently curved crystal aggregates cnsisting f 6 t 10 plagiclase and pyrxene crystals strung singly tgether end-t-end. The chains are 0.3 t 0.6 mm lng. There are very thin glassy selvages n the inside f sme f the vesicles. Darker, aphyric quench textured material ccurs as 2 mm patches and lining vesicles; s abundant arund vesicles n ne side f slide that it makes up mst f the grundmass. A 1112 pint cunt gives 51.6% messtasis (including crystallites) 3.1 plagiclase phencrysts; 1.0% clinpyrxene phencrysts, 3.2 % grundmass paques; 2.4% grundmass plagiclase; 2.8% grundmass clinpyrxene; 35.7% pen vesicles; 0.2% hematitic patches. Rck is fresh t slightly altered. 913