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IODP Expedition 330:
Louisville Seamount Trail
Week 2 Report (20-26 December 2010)
PDF file is available for download.
824 nmi transit from Auckland to the first site of Expedition 330 was
accomplished at an average speed of 10.3 knots. The vessel was positioning on
Site U1372 (Prospectus Site LOUI-1C) by 1700 hr on 21 December. The corrected PDR water depth referenced to the dual elevator stool on the rig floor was 1960.3 mbrf.
drill string was deployed in routine fashion to 1885 mbrf and a pressure test
was performed on the new non-magnetic sinker bar for the third-party Göttingen Borehole Magnetometer (GBM). The GBM sinker bar was deployed in the drill string via the logging cable at 0300 hr on 22 December and recovered by 0550 hr. The unit did not leak.
the driller tagged the seafloor at 1968.5 mbrf with the bit, the top drive and
knobbies were picked up and Hole U1372A was spudded with the RCB at 0850 hr on
22 December. Initially, the driller could not apply very much weight on bit
because the bottom hole assembly (BHA) was not buried. As a consequence, the
rate of penetration (ROP) was very slow for the first few cores. Eventually,
the ROP increased as the hole was deepened and more bit weight was applied.
Basaltic basement (i.e., the first lava flow) was penetrated at 45.6 mbsf. The
hole was deepened to 145.0 mbsf (99.4 m into basement) by the early morning of
26 December. At this juncture, it was time to change the bit since it had
accumulated 64.4 rotating hours. The average ROP for the hole was 2.3 m/hr and
2.2 m/hr in basement. The average recovery was 68.9% for the entire hole and
64.8% while coring into basement.
to the deployment of the free fall funnel (FFF), the vibration isolated
television (VIT) was launched to observe the hole and the nature of the
seafloor. The hole could not be seen because a cloud of heavy mud was suspended
over the site. Following the recovery of the VIT, a FFF was made up and
deployed at 1010 hr on 26 December. The VIT was then launched again to monitor
the position of the FFF, which was mostly obscured by a cloud of heavy mud.
However, it was obvious the funnel was upright with the three flotation balls
clearly visible. While being observed via the VIT, the bit was withdrawn from
the hole at 1140 hr on 26 December. The VIT was recovered concurrent with the
retrieval of the drill string. The bit cleared the rotary table at 1700 hr and
was found to be in very good condition and only under-gage by 1/16". Once a new
bit and a rebuilt mechanical bit release (MBR) were made up, the BHA was
deployed with an extra stand of drill collars. The FFF was reentered at 0100 hr
on 27 December.
the first week all laboratory groups revised the Methods chapter for the
expedition report, and the descriptive laboratory groups modified the DESClogik
templates (the application that captures descriptive information and uploads it
into the LIMS data base). The workflow for core descriptions was discussed and
agreed upon by all igneous petrologists, alteration specialists, structural
geologists and sedimentologists. In addition, the workflow for shipboard
measurements and sampling was developed with involvement of all groups. The
following summarizes the activity and preliminary results of the respective
scientific disciplines since the first core arrival on December 22.
macroscopic core, smear slide and thin section observations at Site U1372, the
sedimentologists identified three stratigraphic units in the cores that were
recovered this week. Unit I is composed of non-consolidated sandy foraminifera
ooze with local occurrences of reworked glass fragments and pumice (Cores
U1372A-1R to -3R). Unit II (Cores U1372A-4R-1 to -8R-2) is composed
predominantly of basalt breccia and conglomerate with a minor interval of
foraminifera limestone that includes Mn-crusts and mollusk fragments. Unit III (Section
U1372A-8R-3 and below) includes the volcanic basement (beginning at 45.6 mbsf).
The first occurrence of lava flow encountered downhole (Section U1372A-8R-3) is
a peperite that includes minor amounts of micritic limestone and fine volcanic
sandstone, most likely devoid of datable fossils. Several subunits are
currently being defined in Unit II, which will provide constraints on the
stratigraphic development and late stage magmatic evolution of the drilled
for biostratigraphic investigations were taken from the core catchers (CC) of
all cores containing unconsolidated sediment (Stratigraphic Unit I: Cores
U1372A-1R to -3R). All were utilized for nannofossil and foraminiferal
analyses. In addition to those samples, one sample was taken at the 0-1 cm
interval from each core section for nannofossil analyses. Those sediments,
composed of winnowed foraminiferal ooze, are likely the result of the
accumulation of selectively coarse sediment due to relatively energetic
intermediate water currents. Large portions of the recovered sediment were
soupy and more or less disturbed so that the original structure or bedding may
have been destroyed. Preliminary age estimations for Samples U1372A-1R-CC and
U1372A-3R-CC are Holocene-Pleistocene and middle Pliocene to late Miocene,
respectively. The middle and late Miocene, and early Pliocene nannofossils and
planktonic foraminifers co-occur in Samples U1372A-3R-CC, which indicates that
there is a hiatus or an interval of very low sedimentation rate at the bottom
of Core U1372A-3R.
three petrology laboratory groups (igneous petrology, alteration petrology and
structural geology) closely collaborated with the sedimentologists for the
description of the igneous clasts encountered in the coarse conglomerate of
Stratigraphic Unit II (see above). The conglomerate is largely composed of
basaltic clasts ranging from aphyric to highly olivine-phyric. The uppermost
flows of the igneous basement (Stratigraphic Unit III) have peperitic tops
implying emplacement into soft carbonate sediments. From 65 to 83 mbsf
(starting in Core U1372A-10R) the lava flows have scoriaceous tops implying
subaerial eruption. Basaltic breccias encountered at 92.43 mbsf (Core U
1372A-13R) were tentatively interpreted as hyaloclastite, and some of the flows
below this level may be pillow lavas, indicating submarine emplacement.
Overall, the lava flows range in composition from aphyric to highly
olivine-phyric with up to 15% olivine phenocrysts. Highly olivine-phyric basalt
containing fresh olivine was encountered from 57.17 to 59.49 mbsf (Core U1372A-9R).
the igneous petrologist focused on the identification and description of
different lithological (flow) units, the structural geologists paid particular
attention on the distribution, size, and orientation of veins, joints, and
aligned vesicles. A particular highlight was the observation of numerous
geopetal structures (filled vesicles where material is deposited horizontally).
All geopetals observed have infills that are presently horizontal or nearly so,
indicating little tilting or faulting of this part of the seamount since its
eruption in the Cretaceous.
alteration petrologists focused on the description of secondary minerals and
other characteristics resulting from seawater alteration of the volcanoclastic
breccias (Stratigraphic Unit II) and the peperite/basaltic flows (Stratigraphic
Unit III). They have closely interacted with the igneous and structural
petrologists to identify and characterize phenocryst alteration and infilling
in veins and vesicles. It appears that the volcanic clasts, comprising the volcanoclastic
breccias of Unit II, are inhomogeneous in terms of alteration, from slightly to
nearly completely altered. Rare occurrences of olivines are in most cases
nearly totally transformed into iddingsite. The peperite of Unit III is
strongly altered (groundmass and olivine phenocrysts), and highly vesicular.
Vesicles are mainly filled with carbonates (calcite?), zeolite, different types
of clay minerals, and occasionally by clayey sediments and micrite. The
basaltic massive flows below the peperite are variably altered. Some flows are
well preserved with occurrence of nearly fresh olivine in particular in the
interior of the flow units. The altered basalts of Unit III are characterized
by iddingtized olivines, presence of clay in the groundmass, and filling of
vesicles by zeolite, carbonates, and clay minerals. The alteration state of
feldspar phenocrysts will be further observed on thins sections that are
currently in production.
sedimentary samples (six from soft sediment, two from sedimentary rock) were
taken from Units I and II by the geochemists for measurement of total organic
carbon, total carbon, and total nitrogen on the CHNS analyzer. Further
measurements are being conducted to determine the capabilities and limitations
of the new miniature X-ray fluorescence instrument, the Thermo Scientific Niton
XL3 Analyzer. Results from measurements of rock slabs and the sawn faces of
pieces of core have been disappointing so far. However, pellets made from
finely ground rock powders yield better results. Processing of eight samples
from clasts of the breccia and conglomerate of lithologic Unit II for ICP-AES
analysis is underway.
physical property laboratory group spent this week running tests on whole core
and discrete samples from all three stratigraphic units as they became
available. All sections from Cores U1372A-2R to -20R have been run through the
Whole Round Multi-Sensor Logger (WRMSL), which records bulk density, magnetic susceptibility,
and P-wave velocity measurements in the case of sediment cores. Sections from
Cores U1372A-2R to -18R have been measured in the Natural Gamma Ray (NGR)
Logger to detect variations in the natural abundance of U, Th, and K.
Nondestructive thermal conductivity measurements have been completed for 12
locations along the working half of the core down through Core U1372A-10R.
Discrete samples from Cores U1372A-4R to -10R were chosen in collaboration with
the paleomagnetists and are now moving through the sequence of paleomagnetic,
P-wave, and moisture and density analysis. Together the process takes
approximately 60+ hours and is done in batches. The full set of measurements is
now completed through Core U1372A-5R. The physical property group has also
spent the week developing an automated data filtering program for processing
core logger data, based on methods developed during IODP Expedition 324. This
program is nearly complete and should be ready for implementation with
Expedition 330 data soon.
measured the remanent magnetization of archive half-cores U1371A-4R through
-13R (in total 72.45 m of core) at 2 cm intervals using the pass-through
cryogenic magnetometer together with alternating-field (AF) demagnetization
over 8 steps up to a peak field of 50 mT using the in-line AF demagnetizer.
Directions of the remanent magnetization have been picked using the principal
component analyses for oriented pieces longer than 10 cm. In addition, AF
demagnetization has also been carried out on 22 discrete 8 cm3 cubes
up to a peak field of 160 mT using the D-Tech AF demagnetizer, with the remanent
magnetization measured with the spinner magnetometer. The first batch of eight
discrete cubes is currently being thermally demagnetized. The majority of the
AF demagnetization data – both continuous and discrete – show
stable remanent magnetization, with some samples exhibiting high coercivity. In
general, the drilling-induced magnetic overprint has been limited, probably due
to the exclusive use of non-magnetic core barrels during this expedition. The
anisotropy of magnetic susceptibility of all discrete samples has been
measured, but not yet analyzed.
330 also sails one microbiologist who spent the first few days at sea preparing the microbiology laboratory
for sampling. Since the arrival of the first core, he has collected two pelagic
sediment samples and nine rock samples from cores down to a depth of 135 mbsf.
Sediment cores were subsampled for cell counts and molecular biology. On all
other rock samples, a regular suite of subsamples was collected for cell
counts, molecular biology and stable isotope analysis. Additionally, three rock
samples were used to set up cultivation experiments, which are underway in the
cold room. A contamination test was performed by injecting fluorescent
microspheres into one of the core barrels and analysis is underway of those
samples (so far with a negative outcome, i.e. no microspheres detected inside
of rock samples).
Education and Outreach
addition to the 29 scientists, one educator and one videographer are sailing on
this expedition. The videographer, capitalizing on the excitement of starting
the expedition, shot footage and produced an introductory music video called "Aboard the JOIDES Resolution." The song was previously recorded in San Francisco. (It is now posted on the Ocean Leadership You Tube channel: www.youtube.com/watch?v=6tDnmyYMCGg as well as on the JR Facebook page: www.facebook.com/video/video.php?v=1771681936528.) Also, the videographer conducted an
informational interview with co-chief scientist Anthony Koppers, wrote a new
song called Calm Before the Core,
and started testing the new system for video conferencing using Wirecast and
Skype, an external firewire camera and professional microphones. She has also
shot 67 GB of footage of ship operations, and is currently researching and
planning the next video, which will be on the specific objectives of Expedition
educator has continued posting daily blogs on the JR website (alternating between three different blogs, each targeted for a different audience) and also
Facebook posts. The JR website had 1,063 visits between December 20-26, 447 of whom were new visitors to the site. The JR Facebook page has received many comments and "likes"
on the week's posts and has increased its followers from 2,175 fans on December
17 to 2,235 fans on December 26. The educator also completed a map showing the
hometowns of each of the 330 science party members and posted it on the JR
website: joidesresolution.org/node/1622. He has continued confirming
videoconferences with schools and museums for January and February and has
begun recruiting scientists to participate. Twenty-eight videoconferences are
Technical Support and HSE Activities
USIO technical staff is engaged in providing full support for coring operations
at Site U1372. Other activities included the following:
1. Completed distribution of supplies and updated inventory.
2. Completed minor software upgrades to various applications.
3. Assisted with repairs to the downhole magnetometer logging tool.
4. Assembled the new core liner engraving system and started software development.
weekly fire and boat drill was held as scheduled on Sunday, December 26.