IODP Expedition 324
Shatsky Rise Formation
Daily Science Report for 31 October 2009
LOCATION: Underway to Townsville (midnight position: 13°20.8'S, 152°11.2'E)
SCIENCE UPDATE: The last regular science meeting was held today. The geochemistry lab group and the downhole loggers presented their last findings from Sites U1350 and U1349. Subsequently, the first seminar was given by Kate Littler ("Climate and carbon-isotopes in the Early Cretaceous: or Why TEX86 is not an email Address"). The igneous sections of cores obtained from Site 1213B during ODP Leg 198 that were re-described by the science party at the beginning of the cruise were laid out again in the core lab. This was done to help develop a common sampling strategy for future postcruise sampling of this interval.
Daily Science Report for 30 October 2009
LOCATION: Underway to Townsville (midnight position: 10°06.8'S, 154°23.4'E)
SCIENCE UPDATE: The last sampling party was held in the core lab. Cores recovered from Site U1350 were sampled for postcruise research.
Daily Science Report for 29 October 2009
LOCATION: Underway to Townsville (midnight position: 05°43.8'S, 153°59.9'E)
SCIENCE UPDATE: Today, the vessel entered the Solomon Sea and crossed the New Britain deep-sea trench. All scientists are busy finishing their methods/explanatory notes for the cruise report. The last lab groups are revising their Site U1350 reports. All scientists provided tentative titles for research papers intended to be written with samples/data from this expedition.
Daily Science Report for 28 October 2009
LOCATION: Underway to Townsville (midnight position: 01°31.0'S, 154°18.7'E)
SCIENCE UPDATE: The third sampling party was held and cores recovered from Sites U1348 and U1349 were sampled for postcruise research.
Daily Science Report for 27 October 2009
LOCATION: Underway to Townsville (midnight position: 02°00.9'N, 154°30.5'E)
SCIENCE UPDATE: Today, the vessel reached the northwestern edge of the Ontong Java Plateau, world's largest igneous plateau. All lab groups are working on the revisions of their last site report and final versions of the methods chapter for the cruise report. The core describing groups are also wrapping up their last thin section description and upload of the data to the LIMS.
Daily Science Report for 26 October 2009
LOCATION: Underway to Townsville (midnight position: 07°10.8'N, 154°51.1'E)
SCIENCE UPDATE: While the vessel crossed the Caroline Island group, the second sampling party was held on board. Cores recovered from Site U1347 were sampled for postcruise research.
Daily Science Report for 25 October 2009
LOCATION: Underway to Townsville (midnight position: 11°37.2'N, 155°16.8'E)
SCIENCE UPDATE: Today, as the vessel is crossing the East Mariana Basin, the last regular site meeting was held. Sedimentology, Paleontology, Physical Properties and Paleomagnetics lab groups presented their results of Site U1350 shipboard research. All scientists are busy writing the last site report and preparing for the next sampling party tomorrow.
Daily Science Report for 24 October 2009
LOCATION: Underway to Townsville (midnight position: 15°54.3'N, 155°49.7'E)
SCIENCE UPDATE: Today, the first Expedition 324 sampling party was conducted. Cores recovered from Site U1346 were sampled for postcruise research. All lab groups are working on their last site reports for Site U1350.
Daily Science Report for 23 October 2009
LOCATION: Underway to Townsville (midnight position: 20°31.4'N, 156°
25.3'E)
SCIENCE UPDATE: Today, the vessel crossed the Mid Pacific Mountains, a
prominent seamount chain in the West Pacific. All lab groups continue
their investigation of thin sections and discrete sample taken from
Hole U1350A cores. In the late morning, a science meting was held and
the petrologists, structural geologists and alteration specialists
presented their preliminary results for Site U1350. In the afternoon,
a research planning meeting was held with all scientists who want to
conduct additional research of Hole 1213B igneous cores (recovered
from Shatsky Rise during ODP Leg 198) to better coordinate their
efforts and to tailor these studies into the Expedition 324 post-
cruise research.
Daily Science Report for 22 October 2009
LOCATION: Underway to Townsville (midnight position: 25°09.0'N, 157°02.1'E)
SCIENCE UPDATE: After finishing the macroscopic description of the last Hole U1350A cores, the petrology, alteration and structural geology lab groups are now busy examining the thin sections produced from these cores. The physical properties, paleomagnetism and geochemistry lab groups have started to measure the discrete samples that were taken from these cores. All scientists have now revised their sample and data requests according to the agreements and sampling/research strategies that were hammered out and refined during the last days.
Daily Science Report for 21 October 2009
LOCATION: Underway to Townsville (midnight position: 29°49.6'N, 157°41.5'E)
SCIENCE UPDATE: In the evening we left the southern flank of Shatsky Rise and are now crossing the abyssal plans of the West Pacific Basin. The scientists continue to work on the last cores from Site U1350. At noon, the last sampling meeting for shipboard analyses was held. The cores from Site U1350 (flank of Ori Massif) turned out to be quite different from the ones cored at Site U1349 (summit of Ori Massif). Whereas the later are olivine-phyric, most Site U1350 rocks are plagioclase-phyric. The white crystallized (marble-like) sediments that are found between the pillow lobes turned out to be rich in radiolaria species but it needs to be checked if the crystallization will hinder their use for biostratigraphic dating. Physical property measurements of Site U1350 samples are in full swing and a distinctive drop in porosity is observed downhole from Core U1350A-20R. Also today, the last research planning meetings were held to tailor postcruise research.
Daily Science Report for 20 October 2009
LOCATION: Underway to Townsville (midnight position: 34°30.2'N, 158°00.3'E)
SCIENCE UPDATE: Detailed examination and description of the last cores recovered from Site U1350 continued today. Discrete samples were prepared for various physical properties measurements (density, P-wave velocity) and the first Site U1350 samples were thermally demagnetized in preparation for paleomagnetism measurements. In the afternoon, a general science meeting was held where the alteration, physical properties, paleomagnetism and geochemistry lab groups presented their results from Site U1349 sample investigations.
Daily Science Report for 19 October 2009
LOCATION: Site U1350 (SRCH-4), 36°04.492'N, 159°17.065'E (lower slope of Central High)
SCIENCE UPDATE: The last cores recovered from Hole U1350A were split and described. Recrystallized bivalve shells were found in the baked limestone that is preserved between pillow lobes. The last cores continue the trend (starting at ~Core U1350A-23R) of showing decreasing magnetic susceptibility and increasing (potassium-generated) gamma ray radiation. Despite all attempts, logging operations could not be conducted due to inexplicable apparent friction that the tool string experienced within the drill pipe. Also today, another research planning meeting was organized to discuss the division of research topics and analytical methods among the subgroup of paleomagnetists and Ar/Ar geochemists (radiometric dating) that will be applied to the recovered Shatsky Rise samples. In the afternoon, a general science meeting was held where the volcanology, petrology and structural geology lab groups presented their results of Site U1349 sample investigations.
Daily Science Report for 18 October 2009
LOCATION: Site U1350 (SRCH-4), 36°04.492'N, 159°17.065'E (lower slope of Central High)
SCIENCE UPDATE: Cores U1350A-24R to -26R recovered more of the moderately plagioclase-phyric basalt. Rounded pillow lobes indicate that this succession represents stacked pillow basalt flows. In some intervals, like in Core U1350A-25R, the basalt is highly plagioclase-phyric with up to 8 mm large plagioclase glomerocrysts. Fresh and altered glass is found along the rims of pillows and patches of sediment are frequently found in the spaces between individual lobes. The sediment is predominantly snow-white baked limestone but Section U1350-25R-1 contains a 17 cm long interval of gray laminated silty mudstone. With the last Core U1350A-26R (306.2 m to 315.8 m CSF-A), drilling operations for Expedition 324 were concluded after reaching 163 m basement penetration at Site U1350. The average recovery of today was an excellent 78%. In the evening, Hole U1350A was prepared for logging operations. Also today, another research planning meeting was conducted to discuss the division of research topics and analytical methods among the subgroup of sedimentologists and paleontologists that will be applied to the recovered Shatsky Rise samples.
Daily Science Report for 17 October 2009
LOCATION: Site U1350 (SRCH-4), 36°04.492'N, 159°17.065'E (lower slope of Central High)
SCIENCE UPDATE: Core U1350A-22R to -23R (267.8 m – 287.0 m CSF-A) recovered more of the well-preserved plagioclase-phyric basalt (the plagioclase phenocryst abundance increases with depth up to moderately phyric). Nice pipe vesicles, more than 20 cm long, occur in Core U1350A-22R. Occasional veins are filled with calcite but fresh glass is present in many intervals. Recovery was 66%. The drill bit seems to be still in good condition and will hopefully enable us to drill one more day. In the morning another research planning meeting was held to discuss the division of research topics and analytical methods among the subgroup of isotope geologists that will be applied to the recovered Shatsky Rise samples. In the afternoon a general science meeting was held and the sedimentologists, paleontologists and alteration specialists presented their findings from Site U1349 (and U1348) to the whole science party.
Daily Science Report for 16 October 2009
LOCATION: Site U1350 (SRCH-4), 36°04.492'N, 159°17.065'E (lower slope of Central High)
SCIENCE UPDATE: Cores U1350A-18R to -21R (229.5 to 267.8 m CSF-A)
continued to recover more of the pleasingly fresh massive basalt with
an average recovery of 31%. A cyclic variation between the plagioclase-
phyric and the aphyric units is observed. Little pieces of sedimentary
interbeds (calcite cemented sandstone) are occasionally found between
individual flows. A hyaloclastite interval (glass rubble) is found in
Section U1350A-19R-2. In the afternoon, the first research planning
meeting was held where the petrologists discussed the division of
research topics and analytical methods among the science party that
shall be applied to the recovered Shatsky Rise samples.
Daily Science Report for 15 October 2009
LOCATION: Site U1350 (SRCH-4), 36°04.492'N, 159°17.065'E (lower slope of Central High)
SCIENCE UPDATE: Cores U1350A-12R to -17R (191.1 to 229.5 m CSF-A) recovered more of the exceptional fresh massive basalt lavas. Starting with Core U1350A-12R the lavas become sparsely plagioclase phyric. Fresh glass rims and occasionally little pieces of (clastic?) sediment are frequently found between individual flows. The average recovery is only 32% but the penetration rate is a good 2.4 m/hr. In the afternoon a science meeting was held and the geochemistry, physical properties and structural geology lab groups presented their results for Site U1348.
Daily Science Report for 14 October 2009
LOCATION: Site U1350 (SRCH-4), 36°04.492'N, 159°17.065'E (lower slope of Central High)
SCIENCE UPDATE: Igneous basement was reached at the top of Core
U1350A‑7R at 152.6 m CSF‑A (consistent with the expected depth of ~157
m calculated from the site survey seismic data). Cores U1350A‑7R to
‑11R (152.6 to 191.1 m) recovered surprisingly fresh, massive basalt
with some fresh glass preserved at the flow margins. Small pieces of
clastic rock (sandstone?) are found between the units. In the
afternoon a science meeting was held, and the science party was
informed about postcruise activities, events and obligations. This
meeting also served to prepare for all activities related to the end
of this expedition in three weeks.
Daily Science Report for 13 October 2009
LOCATION: Site U1350 (SRCH-4), 36°04.492'N, 159°17.065'E (lower slope of Central High)
SCIENCE UPDATE: The first cores at this site, U1350A-1W to -5R (0.0 m to 143.0 m CSF-A) recovered the expected few chert fragments representing the largely non-recovered sedimentary pile. Core U1350A-6R (143.0 to 152.6 m) contained two small pieces of gray, aphyric basalt below a piece of black chert. A science meeting was held in the afternoon where the sedimentologists, paleontologists and petrologists presented their results from investigations of the volcanoclastic material recovered at Site U1348.
Daily Science Report for 12 October 2009
LOCATION: In transit to Site U1350 (SRCH-4), located at 36°04.492'N, 159°17.065'E (lower slope of Central High)
SCIENCE UPDATE: Logging operation in Hole U1349A continued during the night. The hole was found in good condition (except for one tight spot just below the end of the pipe) and both tool strings (triple combo and FMS-sonic) were run successfully and retrieved excellent data. Logging operations were concluded at 09:30. After the drill string and beacon were recovered, the ship left for Site U1350 in the early evening. The last (lowermost) cores from Hole U1349A were processed and cut during the day. Compared to the igneous basement rocks above, the greenich-gray, (auto?)-brecciated cores below U1349A-14R show a dramatic drop in magnetic susceptibility.
Daily Science Report for 11 October 2009
LOCATION: Site U1349 (SRCH-5) located at 36°06.944'N, 158°27.526'E (Central High)
SCIENCE UPDATE: Core U1349A-14R (221.7 to 231.3 m CSF-A) recovered more of the amygdaloidal basalt flows. In Sections U1349A-14R-1 and -2 a gradual change to a more brecciated structure is observed tentatively interpreted as a possible flow-breccia (involving auto-brecciation?). This change is accompanied by a lively and beautiful transition of colors from yellowish-brownish to greenish-turquoise and spotty dark gray. Cores U1349A-15R and -16R (231.3 m to 250.4 m CSF-A) recovered more of the greenish flow breccia including many dark, vesicular clasts or lava patches that appear less altered and are suitable for most geochemical analyzes and probably age dating. White calcite veins are abundant in all cores. The average recovery of the three cores was an excellent 82%.
At noon a science meeting was held to discuss the options and drilling strategies for the remaining operational time of this expedition. Based on the scientific results from Site U1349 and from other sites that were drilled on Shatsky, it was decided to terminate drilling at Site U1349 and move on to the next drill site. Since it was assumed that Site SRSH-8, originally planned as the next drill site, will penetrate the very same flows that were drilled during Leg 198 in Hole 1213B (and which have been re-described by this science party during the transit from Yokohama to Shatsky Rise), it was decided to drill Site SRCH-4 instead. This is an alternate site located on the deep flank of the Central High (Ori Massif) and its igneous basement is believed to represent the early, initial onset of volcanism at the Central High. Getting datable material from the initial onset of volcanism at a certain place is important for the reconstruction of age progression throughout Shatsky Rise. Furthermore, by comparison with samples from the current Site U1349 (on the top of the Central High), which is assumed to represent a later, more alkalic (?) stage of volcanism, we would be able to reconstruct the temporal and geochemical evolution of the whole massif. Therefore, drilling at Site U1349 was terminated at 14:30 hr at 250.4 m CSF-A (85 m into basement) and the hole was prepared for logging operations. The triple combo logging tool was deployed in the early evening and logging continued throughout the night without any incidents.
Daily Science Report for 10 October 2009
LOCATION: Site U1349 (SRCH-5) located at 36°06.944'N, 158°27.526'E (Central High)
SCIENCE UPDATE: Cores U1349A-11R to -13R (192.9 m to 221.7 m CSF-A)
recovered more amygdaloidal, olivine-phyric basalt (all olivines are
highly oxidized though). Calcite veins/fillings are abundant and
occasionally cm-wide bands of a bright, pistachio-green secondary
mineral that could be epidote (needs further examination). The
occurrence of epidote would indicate low-grade (high temperature)
metamorphism. Recovery rate continues to be excellent (56% to 80%).
Daily Science Report for 9 October 2009
LOCATION: Site U1349 (SRCH-5) located at 36°06.944'N, 158°27.526'E (Central High)
SCIENCE UPDATE: Core U1349A-6R continued to recover grey
volcaniclastic breccia. With Core U1349A-7R (164.1 to 168.9 m CSF-A)
the character of the clastic sediment changes: the uppermost 96 cm of
the core are composed of a yellow gravel- and pebble-sized
conglomerate with abundant vesicular basalt clasts. At 96 cm from the
top of the core, igneous basement is reached (exactly at the predicted
depth of ≈165 mbsf based on the seismic site survey data). The rest
of core -7R and the following Cores U1349A-8R to 10R (168.9 to 202.5 m
CSF-A) are composed of reddish, highly amygdaloidal basalt (in parts
sparsely olivine phyric, although all olivines are oxidized). Because
of the style of weathering and the presence of subaerial-looking red
scoria at the top of Core U1349A-10R, a subaerial formation of the
basalt is tentatively assumed (needs to be verified by closer
examinations including thin section studies). On the other hand,
calcite is abundant in the basalts, filling vesicles and veins and
sometimes forming near collector-quality druses (crystal clusters).
The average recovery rate in basement was greater than 50% today. In
the afternoon a science meeting was held and the logging scientists
presented their processed results from Site 1347 and first results
from Site 1348.
Daily Science Report for 8 October 2009
LOCATION: Site U1349 (SRCH-5) located at 36°06.944'N, 158°27.526'E (Central High)
SCIENCE UPDATE: After arrival at Site U1349, drilling was initiated in
the early morning. The wash barrel U1349A-1W (0 m to 116 m CSF-A)
recovered three pieces of Cenomanian chert. Core U1349A-2R (116 m to
125 m) contained only 10 cm pink pelagic ooze of Late Albian age.
Subsequent Cores U1349A-3R to -4R recovered more pieces of reddish
chert and a few centimeters of sand/gravel with chert fragments. Core
U1349A-5R (144.8 m to 154.5 m) contained some small fragments of
yellow conglomerate and a red chert at the topmost 10 cm followed by
5.8 m of volcaniclastic breccia, which appears very similar in color,
texture and composition to the volcaniclastic succession that was
cored at the previous Site U1348.
Daily Science Report for 7 October 2009
LOCATION: In transit to Site U1349 (SRCH-5) located at 36°06.944'N, 158°27.526'E (Central High)
SCIENCE UPDATE: After the recovery of the jammed FMS-sonic tool, the ship started its transit to Site U1349 in the morning. Further examination of Hole U1348A samples revealed that the lowermost cores are predominantly composed of igneous material (Cores U1348A-23R to -26R). At noon, a science meeting was held and the geochemistry, physical properties and paleomagnetic lab groups presented their results from Site U1347.
Daily Science Report for 6 October 2009
LOCATION: Site U1348 (SRSH-6). 34°24.940'N, 159°22.907'E (Northern slope of the Southern High)
SCIENCE UPDATE: The second logging tool (FMS-sonic) was successfully run but the tool jammed in the drill pipe during retrieval requiring a number of complex attempts to recover the tool. Meanwhile, the remaining unprocessed cores from Site U1348 were split and described. The siliciclastic-carbonate-cemented breccias become highly altered and below Core U1348A-23R no more bioclastic material can be detected macroscopically.
Daily Science Report for 5 October 2009
LOCATION: Site U1348 (SRSH-6). 34°24.940'N, 159°22.907'E (Northern slope of the Southern High)
SCIENCE UPDATE: Cores U1348A-21R to -26R (266.6 m to 324.1 m CSF-A) continued to recover mixed siliciclastic-carbonate-cemented breccias. Upon closer examination, the existence and amount of volcaniclastic material within these cores became a subject of debate. Everyone is waiting for the arrival of the first thin sections, which will help to answer these questions. Beginning with Core U1348A-19R, the succession becomes more bioclastic-rich (with evidence of relatively shallow water fossils). Nevertheless, after having penetrated more than 120 m through this material, and with no sign of reaching any basement soon, a science meeting was held and it was collectively decided to stop further drilling at this site. The hole was prepared for logging operations and in the late evening the first tool string (triple combo) was successfully deployed.
Daily Science Report for 4 October 2009
LOCATION: Site U1348 (SRSH-6). 34°24.940'N, 159°22.907'E (Northern slope of the Southern High)
SCIENCE UPDATE: Today's cores recovered a variety of different lithologies. Whereas Cores U1348A-8R and -9R (141.9 to 161.1 m CSF-A) contained only a few pieces of bright red (-8R) and yellow (-9R) chert, with the latter probably jasper, Core U1348A-10R recovered white, pelagic ooze at the top followed by yellow, calcite cemented, bioclastic-rich sandstone. This coarse-grained sandstone dominates the following Cores U1348A-11R to -13R (170.7 to 199.5 m CSF-A) and also includes glauconitic grains. Sections U1348A-12R-1 and -CC contain two 10-15 cm thick bright green clay intervals (altered volcanic ash layers?), interrupted by bright white, but less than 1 cm layers of sponge spicules. Downhole, the sandstone shows a finer grain size and layering. With Core U1348A-14R the character of the lithology changes drastically: Cores U1348A-14R to -20R (199.5 m to 266.6 m CSF-A) recovered light gray, volcaniclastic, calcite-cemented breccias containing small to very coarse (cm-size) clasts of dense, aphyric igneous rock (basalt?) and light-colored scoria. Although appearing unsorted in most cores, some sections (e.g., U1348A-15R-1) show graded bedding (partly fine-laminated with some slump structures). At midnight, the hole reached a depth of ~270 m CSF-A and we have not reached igneous basement.
Daily Science Report for 3 October 2009
LOCATION: Site U1348 (SRSH-6). 34°24.940'N, 159°22.907'E (Northern slope of the Southern High)
SCIENCE UPDATE: After washing through the uppermost sediments, coring commenced at 84 m CSF-A. Core U1348A-2R (84.2 m to 93.8 m CSF-A) recovered 1.4 m of soft pelagic ooze of Campanian/Santonian age. Cores U1348A-3R to -7R (93.8 to 141.9 m) recovered various pieces of reddish and yellow chert. All lab groups are working on their Site U1347 reports.
Daily Science Report for 2 October 2009
LOCATION: Arrived at Site U1348 (SRSH-6). 34°24.940'N, 159°22.907'E (Northern slope of the Southern High)
SCIENCE UPDATE: In the early afternoon, the ship arrived at the new site (prospectus site SRSH-6), located 115 nm north of previous Site U1347, on the gentle declining northern slope of the Southern High (TAMU Massif). All lab groups started working on their Site U1347 reports. Throughout the day, a sampling party for sedimentary samples was conducted.
Daily Science Report for 1 October 2009
LOCATION: Site U1347 (SRSH-3B). 32°30.476'N, 159°14.079'E (Southern High)
SCIENCE UPDATE: We continued logging Hole U1347A. The FMS-sonic tool was successfully run (two complete passes). Unfortunately, deployment of the third logging tool string (including the UBI) failed because parts of the tools were not responding. Preliminary core-log correlation is already underway (e.g., excursions in natural gamma ray correlate nicely with recovered sedimentary intervals within the lavas). We pulled out of the hole in the late evening, recovered the drill string and prepared the ship for the 115 nm transit to the next site (SRSH-6).