Site 638

Abstract

Time on hole: 18 hr Position: 42°09.2'N, 12°11.8'W Water depth (sea level, corrected m, echo-sounding): 4661 Water depth (rig floor, corrected m, echo-sounding): 4671 Bottom felt (m, drill pipe): 4673 Penetration (m): 44 Number of cores: None Total length of cored section (m): 0 Total core recovered (m): 0 Core recovery (%): 0 1 Time on hole: 6 days, 21 hr Position: 42°09.2'N, 12°11.8'W (100 m east of Hole 638A) Water depth (sea level, corrected m, echo-sounding): 4661 Water depth (rig floor, corrected m, echo-sounding): 4671 Bottom felt (m, drill pipe): 4673 Penetration (m): 431.1 Number of cores: 45 Total length of cored section (m): 431.1 Total core recovered (m): 210.5 Core recovery (%): 49 Deepest sedimentary unit cored: Depth sub-bottom (m): 431.1 Nature: sandstone and claystone Age: late Valanginian Measured vertical sound velocity (km/s): 4.0 and 2.2, respectively HOLE 638C Time on hole: 12 days, 16 hr Position: 42°09.2'N, 12°11.8'W (100 m east and 30 m south of Hole 63 8 A) Water depth (sea level, corrected m, echo-sounding): 4661 Water depth (rig floor, corrected m, echo-sounding): 4671 Bottom felt (m, drill pipe): 4673 Penetration (m): 547.2 Number of cores: 14 Total length of cored section (m): 135.3 Total core recovered (m): 37.7 Core recovery (%): 28 Deepest sedimentary unit cored: Depth sub-bottom (m): 547.2 Nature: sandstone and claystone Age: Valanginian Measured vertical sound velocity (km/s): 4.4 and 2.5, respectively Principal results: Three holes were drilled at Site 638: Hole 638A as an engineering test hole, Hole 638B as a pilot hole to prepare for reen try operations, and Hole 638C as a multiple reentry hole. The stratigraphic column, combining data from Holes 638B and 638C, to a depth of 547.2 meters below seafloor (mbsf), shown graphi cally in Figure 1, consists of the following intervals: 1. 0-183.6 m: upper Miocene to Pleistocene nannofossil ooze and chalk, occurring as a submarine valley fill. 2. 183.6-212.6 m: upper Barremian bioturbated micrite and coup lets of laminated claystone and marlstone. SITE 638 it; I''.,, iaSKS i .,.!.. ;.:.) V v.\',i,