Site 1190 is located on a portion of Pual Ridge where no surficial evidence of hydrothermal activity has been observed. The intention of drilling this site was to recover a "background" sequence of less-altered volcanic rocks to investigate the volcanic architecture of Pual Ridge. Recovery was poor, and it was necessary to abandon all three holes drilled at the site at shallow depths (Hole 1190A: 6.0 mbsf; Hole 1190B: 8.6 mbsf; Hole 1190C: 17.2 mbsf).
Almost all pieces of core recovered from holes drilled at Site 1190 were fresh volcanic rock (<2% altered). Two pieces (intervals 193-1190B-2R-1, 12-16 cm, and 2R-1, 19-28 cm) were classified as slightly altered and showed evidence of incipient bleaching of the glassy volcanic groundmass. The remaining core pieces exhibited no evidence of pervasive alteration. Most showed rare white hairline siliceous veinlets, poorly developed patchy blue-gray silica ± clay films, and very rare orange iron oxide films and spotting on vesicle walls and fracture surfaces. Fine-grained short prismatic zeolite (heulandite?) crystals were observed to line vesicles in one sample (interval 193-1190B-2R-1, 19-28 cm). A rare, well-developed, pale yellowish alteration crust on another piece (interval 193-1190B-2R-1, 34-38 cm) exhibited very fine rod-shaped white crystals, dark red-brown oxide spots, and rare white botryoids. The crust fizzed gently in HCl, suggesting the presence of calcium carbonate.
Four thin sections were cut from Holes 1190A, 1190B, and 1190C. All sections showed no evidence of alteration. A single X-ray diffraction analysis (Table T4) detected igneous plagioclase, augite, and possible traces of smectitic clay.
The alteration exhibited by material recovered from Site 1190 is similar to that observed for fresh near-surface volcanic rocks from Sites 1188 and 1189 and is consistent with an absence of hydrothermal activity at Site 1190. However, because of the shallow penetration at Site 1190, it is not possible to preclude the presence of hydrothermally altered rocks at depth. A detailed description of the limited alteration in individual core pieces is presented in the in the alteration tables (see the "Site 1190 Alteration Log").