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IODP Expedition 330 Louisville Seamount Trail

Daily Science Report 11 -- Wednesday, 22 December 2010


Site U1372 on 26.5°S Guyot 26° 29' 35.9988" S, 174° 43' 45.0012" W
Louisville Seamount Trail
0 m above sea level

After the pressure test for the new non-magnetic sinker bar was successfully completed in the morning hours (the unit did not leak), the drill string tagged seafloor at 1968.5 meters below rig floor. Hole U1372A was spudded at 08:50 hr and the first core of Exp. 330 was recovered shortly afterwards. In total, five cores (U1372A-1R to -5R) were retrieved before midnight. Whereas Core U1372A-1R retrieved only ~10 cm of unconsolidated sediment, Cores U1372A-2R (0.1-9.7 mbsf) and -3R (9.7-13.5 mbsf) recovered 7.55 m and 2.74 m of soft sediment respectively (corresponding to 79% and 72% recovery). Subsequent cores U1372A-4R (13.5-18.0 mbsf) and -5R (18.0-23.5 mbsf) retrieved cemented volcaniclastic lithologies with 100% and 115% recovery. 

For all cores, the non-magnetic core barrel assembly was used and fluorescent microspheres (for microbiologic contamination testing) were deployed in U1372A -1R. To everyone’s excitement and joy, the five cores yield a variety of different lithologies and rock types.

Cores U1372A-1R to -3R recovered a light-brown foraminifer sand (containing mainly planktonic foraminifers and epiclastic volcanic fragments). Preliminary biostratigraphic age determinations reveal recent to Pleistocene (U1372A-1R), Pliocene to Pleistocene (U1372A-2R) and early Pliocene (U1372A-3R) ages. Cores U1372A-4R and -5R recovered colorful volcaniclastic breccia composed of pebble- to bolder-size clasts in a white carbonate matrix. The volcanic clasts have different lithologies and their preservation stage range from very altered to almost fresh.

Samples for microbiologic investigation were taken from four cores and prepared for post-cruise molecular and cell count studies. From Core U1372A-1R cultivation experiments were set up.