Table T6. Summary of volcaniclastic components at Site 1138.

Unit/Subunit Core, section,
interval		 Depth to
top of unit
(mbsf)		 Thickness
(m)		 Age Lithologies with
volcanic
components		 Volcanic
components		 Authigenic and
secondary minerals
Lithologic:

 



I 1R-1, 0 cm, to 13R, 0 cm
0-112.00
112.00 late Miocene to late Pleistocene Foraminifer-bearing diatom clay and ooze Mixed disseminated volcanic ash with feldspar crystals, pumice lapilli, broken pumice (forming shards), brown (basaltic) glass, and lithic fragments. Green clay (nontronite?) forming on basaltic glass rims, brown volcanic clay.
I, II, and IIIA 1R-1, 0 cm, to 53R, 0 cm
0-496.40
496.40 late Maastrichtian to late Pleistocene Foraminifer-bearing diatom clay and ooze; foraminifer-bearing nannofossil clay, ooze, and chalk Discrete pyroclastic fall deposits forming cm thick tephra layers. Some are dominated by brown (basaltic) glass ± lithic fragments, and others by pumice ± feldspar crystals (see Table T10). Green clay (nontronite?) forming on basaltic glass rims, brown clay in matrix of glassy intervals. Glauconite in lowermost discrete basaltic ashes.
Basement:
 



1 74R-1, 0 cm, to 76R-1, 0 cm
698.10-717.40
19.30 Cretaceous Aphyric dacite Abraded, flow-banded, aphyric, dacite cobbles with spherulitic texture. Spherulitic alteration (silicification) and pale brown clay minerals along flow banding.
2 76R-1, 0 cm, to 79R-4, 87 cm
717.40-741.89
24.49 Cretaceous Trachytic pumice lithic breccias and ash deposits Pumice lithic breccia, lithic breccia with pumice, ash-fall deposits with accretionary lapilli, highly altered pumice-rich clays, massive volcanic clays (see Figure F13). A wide variety of alteration from red to pale green, abundant smectite, and minor kaolinite clay minerals.