(Table T1) Physical properties of minicores from ODP Leg 193 sites, PACMANUS field

Permeability of the ocean crust is one of the most crucial parameters for constraining submarine fluid flow systems. Active hydrothermal fields are dynamic areas where fluid flow strongly affects the geochemistry and biology of the surrounding environment. There have been few permeability measurements in these regions, especially in felsic-hosted hydrothermal systems. We present a data set of 38 permeability and porosity measurements from the PACMANUS hydrothermal field, an actively venting, felsic hydrothermal field in the eastern Manus Basin. Permeability was measured using a complex transient method on 2.54-cm minicores. Permeability varies greatly between the samples, spanning over five orders of magnitude. Permeability decreases with both depth and decreasing porosity. When the alteration intensity of individual samples is considered, relationships between depth and porosity and permeability become more clearly defined. For incompletely altered samples (defined as >5% fresh rock), permeability and porosity are constant with depth. For completely altered samples (defined as <5% fresh rock), permeability and porosity decrease with depth. On average, the permeability values from the PACMANUS hydrothermal field are greater than those in other submarine environments using similar core-scale laboratory measurements; the average permeability, 4.5 x 10-16 m**2, is two to four orders of magnitude greater than in other areas. Although the core-scale permeability is higher than in other seafloor environments, it is still too low to obtain the fluid velocities observed in the PACMANUS hydrothermal field based on simplified analytical calculations. It is likely that core-scale permeability measurements are not representative of bulk rock permeability of the hydrothermal system overall, and that the latter is predominantly fracture controlled.

Dissolved organic carbon in sediments of the central Arctic Ocean collected during POLARSTERN cruise ARK-XXVII/3 from August-September 2012

Marine organic matter (OM) sinks from surface waters to the seafloor via the biological pump. Benthic communities, which use this sedimented OM as energy and carbon source, produce dissolved organic matter (DOM) in the process of remineralization, enriching the sediment porewater with fresh DOM compounds. We hypothesized that in the oligotrophic deep Arctic basin the molecular signal of freshly deposited primary produced OM is restricted to the surface sediment pore waters which should differ from bottom water and deeper sediment pore water in DOM composition. This study focused on: 1) the molecular composition of the DOM in sediment pore waters of the deep Eurasian Arctic basins, 2) whether the signal of marine vs. terrigenous DOM is represented by different compounds preserved in the sediment pore waters and 3) whether there is any relation between Arctic Ocean ice cover and DOM composition. Molecular data, obtained via 15 Tesla Fourier transform ion cyclotron resonance mass spectrometer, were correlated with environmental parameters by partial least square analysis. The fresher marine detrital OM signal from surface waters was limited to pore waters from < 5 cm sediment depth. The productive ice margin stations showed higher abundances of peptides, unsaturated aliphatics and saturated fatty acids formulae, indicative of fresh OM/pigments deposition, compared to northernmost stations which had stronger aromatic signals. This study contributes to the understanding of the coupling between the Arctic Ocean productivity and its depositional regime, and how it will be altered in response to sea ice retreat and increasing river runoff.

Sm-Nd isotope and Mn/Ca ratios for cleaned Neogloboquadrina pachyderma from ODP Hole 105-647A (Table 1)

The neodymium (Nd) isotope composition of ancient seawater is a potentially useful tracer of changes in continental inputs and ocean circulation on timescales of a few ka. Here we present the first Nd isotope record for seawater using sedimentary foraminifera cleaned using standard oxidative-reductive techniques. The data, along with Mn/Ca ratios, suggest that cleaned foraminifera provide a reliable record of Nd in seawater and hold out the prospect of using Nd in foraminifera to examine changes in seawater that accompany glacial-interglacial climatic cycles. The principal potential problem to be overcome with the use of forams as records of trace elements in ancient seawater is their diagenetic Fe-Mn coatings. These contain large amounts of Nd and other trace elements but can be cleaned off using highly reducing reagents. Mn(Ca ratios for the majority of the cleaned sedimentary foraminifera analysed here lie within the range (10-100 µmol/mol) that has yielded success in studies of transition elements in forams. Mass-balance modelling suggests that for residual Mn/Ca ratios <100 µmol/mol, Nd added to the foram in the coating will never shift the measured Nd isotope composition significantly away from the seawater value acquired by the foram test in the water column. Additionally, Nd concentrations measured in cleaned sedimentary foraminifera are comparable with those for a modern sample that has never encountered diagenetic fluids. Finally, core-top planktonic foraminifera for two sites have Nd isotope compositions that are identical to local surface seawater. The data we present here for Labrador Sea forams over the past 2.5 m.y. are interpreted in terms of changes in the seawater isotopic composition. The data show a pronounced shift from epsilon-Nd values of ~-12 to ~-19 in the period 2.5-1.5 Ma. This change is interpreted to result from the initiation of Northern Hemisphere glaciation and the increased derivation of Labrador Sea Nd via ice-rafting from Archaean terranes in central Canada. In combination with stable isotope and foraminiferal relative species abundance data, the new Nd data are consistent with the surface hydrography of the Labrador Sea being dominated by a fluctuating balance between cold, polar waters containing unradiogenic Nd and warm, subtropical waters containing more radiogenic Nd. The major change in Labrador Sea Nd that is observed in the past 2.5 Ma can, on its own, account for the change in the Nd isotope composition of North Atlantic Deep Water over the same time period.

Core correlation data and revised composite depth scale of Exp302 (ACEX) cores

Expedition 302 of the Integrated Ocean Drilling Program (IODP), also known as the Arctic Coring Expedition (ACEX), successfully penetrated a sequence of Cenozoic sediments draping the crest of the Lomonosov Ridge in the central Arctic Ocean. The cumulative sedimentary record spans the last 57 m.y. and was recovered from three sites located within 15 km of each other. Merging the recovered cores onto a common depth scale that accurately reflects their stratigraphic placement below the seafloor is a fundamental step toward interpreting this unique sedimentary record. However, the lack of overlapping recovery in adjacent holes and intervals of high core disturbance complicated traditional methods of stratigraphic correlation. Here we present a revised composite depth scale for the ACEX sediments, generated in part by performing a regional stratigraphic correlation with sediments recovered from previous expeditions to the Lomonosov Ridge. The revised depth scale also reassesses the offsets for cores in the upper 55 meters below seafloor, where no overlapping recovery was acquired, and proposes modifications to these depths.

Strontium and boron geochemistry of ODP sites at Hydrate Ridge, eastern Pacific Ocean

ODP Leg 204, which drilled at Hydrate Ridge, provides unique insights into the fluid regime of an accretionary complex and delineates specific sub-seafloor pathways for fluid transport. Compaction and dewatering due to smectite-illite transition increase with distance from the toe of the accretionary prism and bring up fluids from deep within the accretionary complex to sampled depths (<= 600 mbsf). These fluids have a distinctly non-radiogenic strontium isotope signature indicating reaction with the oceanic basement. Boron isotopes are also consistent with a deep fluid source that has been modified by desorption of heavy boron as clay minerals change from smectite to illite. One of three major horizons serves as conduit for the transport of mainly fluid. Our results enable us to evaluate fluid migration pathways that play important roles on massive gas hydrate accumulations and seepage of methane-rich fluids on southern Hydrate Ridge.

(Table 3) Foraminiferal 87Sr/86Sr ratios and ages of ODP Hole 162-986D sediments

Site 986 was drilled to 965 meters below seafloor (mbsf) on the western Svalbard margin to record the onset of glaciations and to date and document the glacial evolution in the Svalbard-Barents Sea region during the Pliocene-Pleistocene. In this paper, results of sedimentological analyses are discussed in light of seismic stratigraphy and new age determinations. The latter were difficult to obtain in the glacial deposits, and datums are sparse. Through combined paleomagnetic data, biostratigraphy, and Sr isotopes, however, an overall chronology for the main evolutionary steps is suggested. The cored sequence at Site 986 is younger than 2.6 Ma, and the lower 60 m of the section contains no evidence of a major glacial influence. An initial glaciation is interpreted to have occurred at ~2.3 Ma, resulting in increased sand deposition from debris flows at Site 986 and forming a prominent seismic reflector, R7. However, glaciers probably did not reach the shelf break until ~1.6-1.7 Ma (Reflector R6), after which the depositional environment was dominated by diamictic debris flows. A gradual change in source area from the Barents Sea to Svalbard is recorded primarily by changes in carbonate and smectite content, ~355 mbsf (Reflector R5), at an interpolated age of 1.4-1.5 Ma. During the last ~1 m.y., Site 986 has undergone more distal deposition as the main depocenters have shifted laterally. This has resulted in less frequent debris flows and more turbidites and hemipelagic deposits, with a slight fining upward of the cored sediments.

(Table 1) AMS radiocarbon ages from ODP Sites 169-1033 and 169-1034

This paper explores the paleoseismic record potentially preserved in the upper 40 m of hydraulic piston cores collected in 1996 at two sites in Saanich Inlet, British Columbia, during ocean drilling program (ODP) Leg 169S. The ODP cores are missing 1-2 m of water-rich sediment directly underlying the seafloor, but this sediment is preserved in shorter piston cores collected in 1989 and 1991. The upper part of the ODP cores consists of rhythmically laminated (varved) marine mud with intercalated massive beds, interpreted to be debris flow deposits. Some of the debris flow deposits are linked to past earthquakes, including the 1946 Vancouver Island earthquake (M7.2), a great (M8-9) plate-boundary earthquake at the Cascadia subduction zone in January 1700, and a large crustal or plate-boundary earthquake about 1000 yr ago. Earthquakes may also be responsible for debris flows in about AD 1600, 1500, 1250, 1150, 850, 450, 350, 180, and BC 200, 220, 500, 900, and 1050. If so, the average recurrence interval for moderate to large earthquakes, which trigger debris flows in Saanich Inlet, is about 150 yr. This recurrence interval is broadly consistent with the frequency of moderate to large earthquakes in the region during the historical period. Debris flows, however, can also be triggered by non-seismic processes, making it difficult to assemble a complete earthquake record from the Saanich Inlet cores. We propose that extensive debris flow deposits, emplaced by single large failures or many smaller coincident failures, probably have a seismic origin.

Major and rare earth element concentrations of basalts beneath ODP Hole 118-735B (Table 3)

A wide-angle seismic experiment at the Atlantis II Fracture Zone, Southwest Indian Ridge, together with geochemical analyses of dredged basalt glass samples from a site conjugate to Ocean Drilling Program hole 735B has allowed determination of the thickness and the most likely lithological composition of the crust beneath hole 735B. The measured Na, composition of 3.3 +/- 0.1 corresponds to a melt thickness of 3 +/- 1 km, a result consistent with rare earth element inversions which indicate a melt thickness of between 1.5 and 4.5 km. The seismic crustal thickness to the north and south of the Atlantis Platform (on which hole 735B is located) is 4 +/- 1 km, and probably consists largely of magmatic material since the seismic and inferred melt thicknesses agree within experimental uncertainty. Beneath hole 735B itself. the Moho is at a depth of 5 +/- 1 km beneath the seafloor. The seismic model suggests that, on average. about 1 km of upper crust has been unroofed on the Atlantis Platform. However, allowing for the inferred local unroofing of 2 km of upper crust at 735B, the base of the magmatic crust beneath this location is probably about 2 km beneath the seafloor, and is underlain by a 2-3 km thick layer of serpentinised mantle peridotite. The P-wave velocity of 6.9 km/s for the serpentinised peridotite layer corresponds to a 35 +/- 10 vol% serpentine content. The Moho beneath hole 735B probably represents a serpentinisation front.

(Table 2) Estimated basement temperatures at DSDP Hole 69-504B

The achievement of deep penetration (562 m) of seafloor basalts at Hole 504B, near the Costa Rica Rift (1°13.63'N, 83°43.81'W), on DSDP Legs 69 and 70 presented a rare opportunity to examine the structure of young (6 m.y.) oceanic crust. In addition to the recovery of samples for laboratory studies, an extensive suite of downhole logs and experiments was carried out at this site, for two main purposes: (1) to allow reliable deductions about the nature of the entire section of penetrated crust, because recovery of samples was far from complete (-25%); (2) to probe the physical state of rock around the drilled hole on a scale of tens of meters to kilometers. Information on the latter large-scale phenomena at Hole 504B were provided mainly by the oblique seismic experiment, utilizing a bore-hole seismometer (Stephen 1983), and by the large-scale-electrical- resistivity experiment described below.

Paleomagnetic properties of ODP Site 119-744 (Appendix)

Paleomagnetic studies conducted on board JOIDES Resolution during Leg 119 indicate that the cores collected at Site 744 range from Quaternary through Eocene in age. Initial studies of the sediments completed on board the ship measured the magnetization of the archive halves of the sedimentary cores, using the pass-through cryogenic magnetometer. Stratigraphic plots of the declination and inclination derived from these measurements displayed numerous long intervals with essentially constant magnetic directions. Further study of these intervals led to a discovery that the background signal had been incorrectly computed due to faulty software on the ship. Because this background signal was not recorded in the data-processing system, corrections could not be made. Therefore, subsequent shorebased studies have been made on the individual samples collected at approximately 30-cm intervals in the cores in order to verify the initial magnetostratigraphy reported in the Initial Reports volume for Leg 119 (Barron, Larsen, et al., 1989, doi:10.2973/odp.proc.ir.119.1989). Numerous reversals were identified and correlations were suggested with the seafloor magnetic anomaly sequence of Berggren et al. (1985, doi:10.1130/0016-7606(1985)96<1407:CG>2.0.CO;2) back to anomaly number 17.

(Table 1) Porosity, particle diameter, ATP content and carbon and nitrogen composition of ODP Site 164-994 sediments

Sediment samples were obtained for detailed Adenosine 5'-Triphosphate (ATP) analysis down to 57.8 m below the seafloor (mbsf). The samples were also analyzed for particle-size distribution, calcium carbonate (CaCO3), organic carbon, and total nitrogen. The concentrations of ATP ranged between 360 and 7050 pg/g (dry weight sediment), which agree well with a limited number of direct bacteria counts. Principal component analyses show that 63% of the total variance can be accounted for by the first two principal components. The concentration of ATP (bacterial numbers by inference) is virtually independent of the concentration of sedimentary organic carbon, but correlates with CaCO3 and coarse particles.

Diatom abundance in sediments of ODP Holes 186-1150A and 186-1151C

The diatom flora from two sediment cores recovered from the upper 27 meters below seafloor (mbsf) in the oceanic frontal area off Sanriku, northeast Japan, during Ocean Drilling Program Leg 186 were analyzed. Diatom abundance seems to be in interglacial stages and suggests a south-north shifting of the frontal area. Diatom temperature values are less reliable because frequency of the warm-water species is smaller. Site 1151 was in a warm climate at ~50 ka, as were Deep Sea Drilling Project Sites 579 and 580 in the western North Pacific Ocean. A mixed diatom assemblage in the upper 3 mbsf at Site 1150 is evidence that the Tsugaru Warm Current flowed into the studied area through the Tsugaru Strait.

Ripple migration directions and grain fabric measurements on ODP Hole 210-1276A sediments

Albian turbidites and intercalated shales were cored from ~1145 to 1700 meters below seafloor at Site 1276 in the Newfoundland Basin. Strata at this level dip ~2.5° seaward (toward an azimuth of ~130°) based on seismic profiles. In contrast, beds dip an average of ~10° in the cores. This higher apparent dip is the sum of the ~2.5° seaward dip and a measured hole deviation of 7.43°, which must be essentially in the same seaward direction. Using the maximum dip direction in the cores as a reference direction, paleocurrents were measured from 11 current-ripple foresets and 11 vector means of grain fabric in planar-laminated sandstones. Five of the planar-laminated sandstone samples have a grain imbrication 8°, permitting specification of a unique flow direction rather than just the line-of-motion of the current. Both ripples and grain fabric point to unconfined flow toward the north-northeast. There is considerable spread in the data so that some paleoflow indicators point toward the northwest, whereas others point southeast. Nevertheless, the overall pattern of paleoflow suggests a source for the turbidity currents on the southeastern Grand Banks, likely from the long-emergent Avalon Uplift in that area. On average, turbidity currents apparently flowed axially in the young Albian rift, toward the north. This is opposite to what might be expected for a northward-propagating rift and a young ocean opening in a zipperlike fashion from south to north.

Geochemistry of ODP Hole 111-504B basalts (Table 2)

Fifty samples of basalt recovered during ODP Leg 111 from the dikes (Layer 2C) of Hole 504B (1350.0-1562.3 m below seafloor) were analyzed by X-ray-fluorescence techniques. All of the samples are highly depleted in magmaphile elements relative to other mid-ocean ridge basalts, with TiO2 = 0.75-1.24 wt%, Na2O = 1.59-2.22 wt%, Zr = 38-64 ppm, Nb = 0.3-1.5 ppm, and Y = 20-30 ppm (for samples containing 0%-2% phenocrysts), but have ratios of highly incompatible elements similar to normal Type I mid-ocean ridge basalts (e.g., Zr/Nb > 30). Abundances of compatible elements are similar to those of typical mid-ocean ridge basalts, with MgO = 7.2-9.2 wt%, Fe2O3* = 9.3-12.5 wt%, Ni = 55-164 ppm, and Cr = 26-388 ppm. Approximately 2% of the samples recovered from the top part of Hole 504B are similar to normal Type I or Type II ocean floor basalts. However, all of the analyzed Leg 111 samples from Hole 504B are depleted basalts. Aphyric dike rocks from Leg 111 are virtually identical to the depleted aphyric samples recovered from the pillow lavas and dikes in the upper 1075 m of Hole 504B during DSDP Legs 69, 70, and 83, with the exception of elements readily altered by seawater (Sr, Rb, and K). These elements reach a maximum in both abundance and variability in the pillow lavas of the upper 571.5 m of Hole 504B and decline to more constant values in the dike system sampled on Legs 83 and 111, apparently as a result of a decrease in porosity and increase in alteration temperatures relative to the pillow lavas. Based on compositional similarities to the vast majority of the pillows and flows, the dikes sampled on Leg 111 appear to be the feeder system for the pillow lavas in the upper part of Hole 504B. The incompatible-element-depleted compositions of the Costa Rica Rift Zone basalts are consistent with multistage melting of a normal mid-ocean ridge source.

Rhenium and osmium concentrations and isotopic compositions in altered ocean crust rocks at ODP Site 185-801

Re and Os concentrations and Os isotopic ratios were determined for composite samples prepared from volcanoclastics (VCL) and basaltic flows (FLO) from Jurassic oceanic crust (Ocean Drilling Program Leg 185, Site 801 in the western Pacific), with the aim of determining the effect of seafloor weathering on the Re-Os budget. A supercomposite sample, prepared from a proportionate mixture of the various composite powders, served to represent the average composition of the altered oceanic crust [Kelley, K.A., Plank, T., Ludden, J. and Staudigel, H., (2003). Composition of altered oceanic crust at ODP Sites 801 and 1149, Geochem. Geophys. Geosyst. 4(6) 8910, doi:10.1029/2002GC000435.]. Re contents vary from 0.2 to 1.3 ng/g, and from 2.2 to 3.1 ng/g in the VCL and FLO composites respectively. Os contents vary from 0.005 to 0.047 ng/g in the VCL, and from 0.008 to 0.027 ng/g in the FLO composites. The FLO composites have much higher Re/Os ratios and thus have more radiogenic Os compositions (187Os/188Os = 1.38 to 8.48) than the VCL composites (187Os/188Os = 0.32 to 4.40). The VCL composite from the upper section of the crust shows evidence for substantial Re loss and Os uptake, consistent with oxidative weathering processes. However, Re uptake during weathering processes under more reducing conditions, evident in the FLO samples from throughout the section and to a lesser extent in the lower VCL samples, more than compensates for this Re loss in the upper VCL. Os concentrations were essentially unchanged by these reductive processes. Model age calculations suggest that Re uptake continued for tens of millions of years after crust formation. Abundant secondary pyrite is found throughout the altered Hole 801C crust in zones of restricted seawater flow, and this may have accommodated an important part of the input Re. The Re content of the supercomposite (~2.2 ng/g) is about 1 ng/g higher than would be expected on the basis of its Yb content. If the results from Hole 801C are typical, they suggest that the Re concentration of at least the upper part of the oceanic crust may be nearly doubled during seafloor alteration. Such large extents of Re uptake would have a significant effect on the oceanic Re budget. Furthermore, assuming that they survive passage through the subduction zone, these elevated Re contents would greatly decrease the proportion of subducted oceanic crust required in the source region to explain the radiogenic Os compositions of many ocean island basalts.