IODP Expedition 330

Louisville Seamount Trail

Daily Science Report for 11 February 2011

LOCATION: Freyberg Wharf, Berth F.D., Port of Auckland, New Zealand

SCIENCE UPDATE: After the last science meeting was conducted, the vessel arrived in Auckland with the first line ashore at 17:09. This ends Expedition 330. In total 1114 m of sediment and igneous basement was cored at 8 holes at 6 sites located on 5 different seamounts, with 806 m of core recovered corresponding to 72% recovery.

Daily Science Report for 10 February 2011

LOCATION: Underway to Auckland. Midnight position 36°48.9' S, 178°41.4' E.

SCIENCE UPDATE: The last site meeting for Site U1377 was conducted in the morning. All lab groups presented their findings and preliminary results. Later today, the scientists submitted their last site reports. Scientists, technical personnel and ship's crew are busy with preparing the labs and the ship for arrival in Auckland. While the ship crossed the Kermadec deep sea trench, magnetic field strength data were collected with the ship's towed magnetometer before the instrument was retrieved early next morning.

Daily Science Report for 9 February 2011

LOCATION: Underway to Auckland. Midnight position 37°12.6' S, 175°53.4' W.

SCIENCE UPDATE: The last sampling for post-cruise studies was conducted for all cores from Site U1377. The first laboratory groups have submitted their Site U1377 Reports and the Co-chief Scientists are busy writing the expedition summary. Cleaning activities in all areas of the laboratory stack are underway.

Daily Science Report for 8 February 2011

LOCATION: Underway to Auckland. Midnight position 37°49.0' S, 172°2.1' W.

SCIENCE UPDATE: Drilling operations for Expedition 330 were concluded this morning. While the vessel is underway to Auckland, all laboratory groups are busy with describing the last core sections, analyzing shipboard samples, and preparing their last site report.

Daily Science Report for 7 February 2011

LOCATION: Site U1377 (Prospectus Site LOUI-4B). Position: 38°10.98' S, 168°38.26' W.

SCIENCE UPDATE: Cores U1377B-1R to -5R were retrieved with 30% average recovery. The first core recovered 1.09 m of predominantly soft, pelagic foraminiferal ooze containing well-preserved Pliocene to recent foraminifers. About 30 cm of basaltic conglomerate covered by a ferromanganese crust was found at the bottom of the core. The conglomerate is cemented by a white limestone matrix that contains planktonic and larger benthic foraminifers. Cores U1377B-3R to -5R contain moderately altered aphyric volcanic rocks displaying grain and vesicle banding interpreted as flow textures. Abundant, slightly rounded glassy margins could indicate that these rocks represent a stack of pillow lavas but the detailed description is still underway. At noon, the series of Site U1376 meetings was concluded with presentations by the Physical Property, Geochemistry, Paleomagnetism and Downhole Logging groups.

Daily Science Report for 6 February 2011

LOCATION: Site U1377 (Prospectus Site LOUI-4B). Position: 38°10.98' S, 168°38.26' W.

SCIENCE UPDATE: Cores U1377A-3R to -6R (15.1 to 53.3 mbsf) were retrieved with 22% recovery and comprise a variety of igneous lithologies. Core U1377A-3R recovered 1.4 m of relatively altered igneous rocks that could represent a dike based on the occurrence of subvertical vesicle bands but no contacts were recovered. Preliminary results of the shipboard ICP geochemical analyses indicate a more evolved, silica-rich composition for this unit. Deeper in the hole is a succession of moderately ol-phyric and aphyric pillow and lava lobe stacks. Core U1377A-6R recovered light gray volcanic rock that is highly amygdaloidal (containing numerous large vesicles filled with secondary minerals). Also present are large pyroxene and olivine phenocrysts with the latter being completely altered to spongy phyllosilicates. When retrieving the core barrel for Core U1377A-6R the hole started to collapse and eventually needed to be abandoned. The decision was made to offset the vessel to the south and to start Hole U1377B, which was spudded shortly before midnight.

Daily Science Report for 5 February 2011

LOCATION: Site U1377 (Prospectus Site LOUI-4B). Position: 38°10.98' S, 168°38.26' W.

SCIENCE UPDATE: Hole U1377A was spudded in the early afternoon. Core U1377A-1R (0-6.1 mbsf) contained only a few cm of foraminifera ooze with abundant recent nannofossils and pumiceous volcanic glass fragments in the core catcher. Core U1377A-2R (6.1-15.1 mbsf) retrieved 14 cm of bioturbated offshore micritic limestone with ferromanganese encrustations. The material contains abundant planktonic foraminifers but the investigation is still ongoing. Sampling for post-expedition research was conducted for Cores U1376A-9R through 23-R.

Daily Science Report for 4 February 2011

LOCATION: Underway to Site U1377 (Prospectus Site LOUI-4B). Midnight Position: 36°41.8' S, 169°28.1' W.

SCIENCE UPDATE: The scientists used the transit day today to catch up with thin section descriptions and report writing. The series of Site U1376 meetings continued with presentations by the Igneous Petrology, Alteration Petrology, and Structural Geology groups.

Daily Science Report for 3 February 2011

LOCATION: Underway to Site U1377 (Prospectus Site LOUI-4B). Midnight Position: 32°34.2' S, 171°41.4' W.

SCIENCE UPDATE: Hole U1376A was successfully logged from 181.1 mbsf up to the pipe (set at ~80 mbsf) with three tool strings: the Triple Combo (natural gamma radiation, density, porosity and resistivity), the third party borehole magnetometer (magnetic field), and the Formation MicroScanner (electrical images of the borehole wall). After completion, the drill string was recovered and the vessel departed for Site U1377 in the late evening. The scientific party is busy preparing site reports and presentations.

Daily Science Report for 2 February 2011

LOCATION: Site U1376 (Prospectus Site LOUI-7A). Position: 32°12.99' S Lat., 171°52.84' W Long.

SCIENCE UPDATE: Cores U1376A-20R to -23R (148.1-182.8 mbsf) were retrieved with 73% recovery. The succession continues downhole with heterolithic breccia in a hyaloclastic matrix. Both matrix and clasts are highly olivine-phyric with up to cm-size olivine crystals of variable preservation stage (fresh to altered). As in the cores above, fresh volcanic glass is abundant and can be found both in the matrix and in some of the clasts. In the lower part of Core U1376A-22R another aphyric dike was encountered that seems to continue into Core -23R (detailed description ongoing). In the late afternoon, the allocated coring time for this site was expended and the hole was prepared for logging. The series of meetings for Site U1376 was opened with presentations by the Sedimentology and Paleontology groups.

Daily Science Report for 1 February 2011

LOCATION: Site U1376 (Prospectus Site LOUI-7A). Position: 32°12.99' S Lat., 171°52.84' W Long.

SCIENCE UPDATE: Cores U1376A-13R to -19R (101.2 to 148.1 mbsf) were retrieved with 63% recovery. With Core U1376-13R we reached the base of the unusually thick (33 m) highly olivine-augite-phyric lava flow and continued drilling into at mixed succession of hyaloclastic breccia and clasts, a smaller olivine-phyric lava flow (2 m thick) and aphyric, sub-vertical sheet intrusions (dikes). Since this material is relatively soft, compared to the massive flow above, the penetration rate increased to 2.9 m/hr. Vast amounts of surprisingly fresh volcanic glass can be found in the hyaloclastite. The excellent preservation of this >65 Ma old glass is particularly astonishing since this seamount hosts by far the largest number of veins (indicating extensive fluid circulation) of all Louisville Seamount drilled during this expedition. Sampling for post-cruise research was conducted today for cores from Holes U1375A, U1375B, and for the upper 50 core sections from current Hole U1376A.