(Table 1) Summary of accelerator mass spectrometer (AMS) radiocarbon ages in ODP Sites 169-1033 and 169-1034

Continuous coring in Saanich Inlet (Ocean Drilling Program, ODP Leg 169S), British Columbia, Canada, yielded a detailed record of Late Quaternary climate, oceanography, marine productivity, and terrestrial vegetation. Two sites (1033 and 1034) were drilled to maximum depths of 105 and 118 m, recovering sediments ranging in age from 13,300 to less than 300 14C yr. Earliest sediments consist of dense, largely massive, gray glaciomarine muds with dropstones and sand and silt laminae deposited during the waning stages of glaciation. Deposition of organic-rich olive gray sediments began in the fjord about 12,000 14C yr ago, under well-oxygenated conditions as reflected by the presence of bioturbation and a diverse infaunal bivalve community. At about 10,500 14C yr, a massive, gray unit, 40-50 cm thick, was emplaced in a very short span of time. The unit is marked by a sharp lower contact, a gradational upper contact and an abundance of reworked Tertiary microfossils. It has been interpreted as resulting from massive flood events caused by the collapse of glacial dams in the Fraser Valley of mainland British Columbia. Progressively greater anoxia in bottom waters of Saanich Inlet began about 7000 14C yr ago. This is reflected in the preservation of varved sediments consisting of diatomaceous spring-summer laminae and terrigenous winter laminae. Correlation of the sediments was based on: marked lithologic changes, the presence of massive intervals (reflecting localized sediment gravity flow events), the Mazama Ash, occasional thin gray laminae (indicative of abnormal flood events in nearby watersheds), varve counts between marker horizons, and 71 accelerator mass spectrometry (AMS) radiocarbon dates.

Stable oxygen isotope record of Neogloboquadrina pachyderma of ODP Sites 177-1091 and 177-1094

Ocean Drilling Program (ODP) cores permit us to extend the study of millennial-scale climate variability beyond the time period that is generally accessible for piston cores (i.e., the last glacial cycle). ODP Leg 177 provided for the first time continuous high sedimentation rate cores along a north-south transect from 41°to 53°S across the main subdivisions of the Southern Ocean (Shipboard Scientific Party, 1999, doi:10.2973/odp.proc.ir.177.101.1999). The main purpose of this drilling was to investigate the Pleistocene and Holocene paleoceanographic history of this region, documented in the sedimentary records. ODP Sites 1094, 1093, 1091, and 1089 accumulated throughout the Pleistocene at rates >10 cm/k.y. and are the most detailed Pleistocene climatic records ever retrieved from the Southern Ocean. These sections provide a unique opportunity to fill an important gap in the knowledge of the paleoclimatic evolution of the high southern latitude regions. The composite sections at each site were generated shipboard using magnetic susceptibility, gamma ray attenuation (GRA) density, and reflectance data to correlate the drill holes and splice together an optimal (complete and undisturbed) record of the sedimentary sequence at each site. A preliminary magnetic polarity stratigraphy was generated on the 'archive' halves of the core sections from each hole, using the shipboard pass-through magnetometer after demagnetization at a single peak alternating field (Shipboard Scientific Party, 1999). During July 1998, we sampled core sections spanning the mid-Pleistocene interval (0.65-1.2 Ma) from Sites 1094, 1093, and 1091 at the ODP Bremen Core Repository and have since then analyzed the stable isotopic ratios of foraminifers in samples from Sites 1094 and 1091. Our goals for these studies are to establish detailed chronology for the mid-Pleistocene Southern Ocean records from Leg 177 using high-resolution stable isotope analyses, and furthermore, to trace the evolution of millennial-scale variability in proxy records from older glacial and interglacial periods characterized by higher-frequency variation. Here, we report on our stratigraphic results to date and describe the laboratory methods employed for sample preparation and stable isotope analysis. Furthermore, we provide tab-delimited text files of the age models.

Stable isotope ratios and abundances of selected foraminifera taxa from ODP Leg 172 sites

This data report describes the results of post-Leg 172 sampling of Sites 1054, 1055, and 1063 for two purposes: to investigate the climatic significance of red-colored intervals in the hemipelagic sediments cored during Leg 172 and to better understand the stratigraphy and chronology of Carolina Slope Sites 1054 and 1055. Gravity cores collected from the Carolina Slope on site survey cruise Knorr 140/2 show very high rates of sedimentation during the Holocene and lower rates during the last glacial maximum (LGM). Because of the high rates, many of the sediments in the recovered cores never reached the LGM. In other cores, it is possible that deglacial oscillations have been mistaken for the LGM. Although radiocarbon dating could solve that problem, some of the gravity cores are at or very close to the Ocean Drilling Program (ODP) sites, and it is useful to compare the isotope stratigraphies among them before proceeding with dating. Furthermore, some of the site survey cores have red-colored intervals and others do not, even though there is some indication they are time equivalent. Either the stratigraphy is wrong, diagenesis has affected the color of the sediment, or red sediment is carried to some sites but not to others that differ in depth by only a few hundred meters.

Geochemistry of ODP Sites 123-765 and 123-766

The sediments of the Argo and Gascoyne abyssal plains are generally lean in organic matter, are immature, and contain hydrocarbons trapped during sediment deposition rather than those generated during sediment catagenesis. TOC concentrations in the Argo Abyssal Plain Cenozoic sediments are 0.5 wt%, and organic matter appears to be from mixed marine and reworked, degraded, organic matter sources, with the latter being contributed by turbidity flows from the nearby continental margin. TOC concentrations within the Cenozoic sediments of the Gascoyne Abyssal Plain are mostly undetectable (<0.1 wt%). Biomarker distributions determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GCMS) indicate that organic matter extracted from the Lower Cretaceous sediments from both sites is predominantly marine with varying contributions from terrestrial organic matter. The specific marine biomarker, 24-n-propylcholestane is in relatively high abundance in all samples. In addition, the relatively high abundance of the 4-methylsteranes with the 23,24-dimethyl side chain (in all samples) indicates significant dinoflagellate contributions and marine organic matter. The ratios of n-C27/n-C17 reflect relative contributions of marine vs. terrestrial organic matter. TOC, while generally low at Argo, is relatively high near the Barremian/Aptian boundary (one sample has a TOC of 5.1 wt%) and the Aptian/Albian boundary (up to 1.3 wt% TOC), and two samples from the Barremian and Aptian sections contain relatively high proportions of terrestrial organic carbon. TOC values in the Lower Cretaceous sediments from Gascoyne Abyssal Plain are low (<0.1 wt%) near the Aptian/Barremian boundary. TOC values are higher in older sediments, with maxima in the upper Barremian (1.02 wt%), the Barremian/Hauterivian (0.6 wt%), and Valanginian (1.8 wt%). Sediments from the upper Barremian contain higher amounts of terrestrial organic carbon than older sediments.

(Table 1) Color, Fe-C-S chemistry and carbonate content from ODP Sites 172-1062 and 172-1063

Reflectance spectra collected during ODP Leg 172 were used in concert with solid phase iron chemistry, carbonate content, and organic carbon content measurements to evaluate the agents responsible for setting the color in sediments. Factor analysis has proved a valuable and rapid technique to detect the local and regional primary factors that influence sediment color. On the western North Atlantic drifts, sediment color is the result of primary mineralogy as well as diagenetic changes. Sediment lightness is controlled by the carbonate content while the hue is primarily due to the presence of hematite and Fe2+/Fe3+ changes in clay minerals. Hematite, most likely derived from the Permo-Carboniferous red beds of the Canadian Maritimes, is differentially preserved at various sites due to differences in reductive diagenesis and dilution by other sedimentary components. Various intensities for diagenesis result from changes in organic carbon content, sedimentation rates, and H2S production via anaerobic methane oxidation. Iron monosulfides occur extensively at all high sedimentation sites especially in glacial periods suggesting increased high terrigenous flux and/or increased reactive iron flux in glacials.

Corg, CaCO3, bulk densities, accumulation rates and ages of ODP Leg 167 sites and three piston cores, California margin

Sediments from five Leg 167 drill sites and three piston cores were analyzed for Corg and CaCO3. Oxygen isotope stratigraphy on benthic foraminifers was used to assign age models to these sedimentary records. We find that the northern and central California margin is characterized by k.y.-scale events that can be found in both the CaCO3 and Corg time series. We show that the CaCO3 events are caused by changes in CaCO3 production by plankton, not by dissolution. We also show that these CaCO3 events occur in marine isotope Stages (MIS) 2, 3, and 4 during Dansgaard/Oeschger interstadials. They occur most strongly, however, on the MIS 5/4 glaciation and MIS 2/1 deglaciation. We believe that the link between the northeastern Pacific Ocean and North Atlantic is primarily transmitted by the atmosphere, not the ocean. Highest CaCO3 production and burial occurs when the surface ocean is somewhat cooler than the modern ocean, and the surface mixed layer is somewhat more stable.

XRF data, magnetic susceptibility, greyscale values and revised depths of sediments from ODP Leg 154 sites

The distinctly cyclic sediments recovered during ODP Leg 154 played an important role in constructing the astronomical time scale and associated astro(bio)chronology for the Miocene, and in deciphering ocean-climate history. The accuracy of the timescale critically depends on the reliability of the shipboard splice used for the tuning and on the tuning itself. New high-resolution colour- and magnetic susceptibility core scanning data supplemented with limited XRF-data allow improvement of the stratigraphy. The revised composite record results in an improved astronomical age model for ODP Site 926 between 5 and 14.4 Ma. The new age model is confirmed by results of complex amplitude demodulation of the precession and obliquity related cycle patterns. Different values for tidal dissipation are applied to improve the fit between the sedimentary cycle patterns and the astronomical solution. Due to the improved stratigraphy and tuning, supported by the results of amplitude demodulation, the revised time scale yields more reliable age estimates for planktic foraminiferal and calcareous nannofossil events. The results of this study highlight the importance of stratigraphy for timescale construction.

Eocene-Oligocene calcareous nannofossil events of ODP Sites from the Southern Ocean

The evolution of the Southern Ocean climate during the late Eocene-late Oligocene interval is examined through highresolution, quantitative calcareous nannofossil analyses on samples from the Southern Ocean sections on Maud Rise and Kerguelen Plateau. We determined the abundance patterns of the counted species to clarify the biostratigraphy, which we correlated with high-resolution magnetostratigraphy [Roberts, A.P., Bicknell, S.J., Byatt, J., Bohaty, S.M., Florindo, F., Harwood, D.M., 2003a. Magnetostratigraphic calibration of Southern Ocean diatom datums from the Eocene-Oligocene of Kerguelen Plateau (Ocean Drilling Program Sites 744 and 748). In: Florindo, F., Cooper, A.K., O'Brien, P.A. (Eds.), Antarctic Cenozoic Palaeoenvironments: Geologic Record and Models. Palaeogeogr., Palaeoclimatol., Palaeoecol. 198 145-168; Florindo, F., Roberts, A.P., in press. Eocene-Oligocene magnetobiochronology of ODP Sites 689 and 690, Maud Rise, Weddell Sea, Antarctica. Geol. Soc. Am. Bull.], and used this data to interpret paleoceanographic changes through the late Eocene to late Oligocene. Percentage plots of the individual species, compared with R-mode principal component and cluster analysis results, allowed us to divide the assemblages into three groups: temperate-water taxa, cool-water taxa, and no temperature-affinity taxa. We attempt correlations between these paleoecological groups and the major sea-surface temperature (SST) variations with tectonic and paleoceanographic changes in the Southern Ocean. During the late Eocene, the nannofossil assemblage data reveal that there were several minor SST decreases (coolings) from 36 to 34 Ma, before the Eocene/Oligocene (E/O) boundary. A sharp cooling event, dated at 33.54 Ma (earliest Oligocene), occurred about 160 kyr after the E/O boundary, which is dated at 33.7 Ma. Relatively stable, cool conditions are interpreted to persist until the latest Oligocene, when an increase in abundance of temperate-water taxa, which corresponds to an antithetical decrease in abundance of cool-water indicators, is recorded. On the basis of our dating, the opening of the Drake Passage, allowing shallow-water circulation, began by 33.54 Ma at the latest, while the establishment of deep-water connections through the Tasmanian Gateway occurred at 33 Ma, as suggested by Exon et al. [Proc. ODP, Init. Rep. 189 (2001) 1].

Pliocene and Pleistocene abundance of siliceous microfossil assemblages in ODP Leg 127 sites

A close examination of the siliceous microfossil assemblages from the sediments of ODP Leg 127, Japan Sea Sites 794, 795, and 797, reveals that upper Pliocene and Pleistocene assemblages have been subjected to more dissolution than have lower Pliocene assemblages. This conclusion is based on semiquantitative observations of samples processed for diatoms and radiolarians. Although preservation of opaline microfossils in some upper Pliocene and Pleistocene samples is better than others, in general, the poorly preserved state of these assemblages supports the notion that opal dissolution, in response to lowered productivity, is responsible for the paucity of siliceous microfossils in upper Pliocene and Pleistocene sediments. The lithological transition from diatomaceous oozes to silts and clays corresponds to a change between dominantly well preserved to more poorly preserved siliceous assemblages, and is termed the late Pliocene Japan Sea opal dissolution transition zone (ODTZ). The base of the ODTZ is defined as the uppermost occurrence of high abundances of moderately to well preserved valves of the diatom Coscinodiscus marginatus. The dissolution transition zone is characterized by partially dissolved refractory assemblages of radiolarians, the presence of C. marginatus girdles, C. marginatus fragments, siliceous sponge spicules, and a general decrease in weakly silicified, less solution resistant diatoms upward in the section. The top of the dissolution transition zone marks the level where whole C. marginatus valves and C. marginatus fragments are no longer present in significant numbers. Dissolution of the late Pliocene and Pleistocene opaline assemblages is attributed mainly to changes in paleoceanographic circulation patterns and decreased nutrient (dissolved silicon) contents of the water column, and possibly dissolution at the sediment/water interface, rather than to post-depositional dissolution or diagenesis. We suggest that the transition from silica-rich to silica-poor conditions in the Japan Sea was due to fluctuations of deep-water exchange with the Pacific through the Tsugaru Strait between 2.9 and 2.3 Ma.

Biogenic opal content in bulk sediments of ODP Leg 181 sites, southwest Pacific

Biogenic opal concentrations were measured on bulk sediments recovered at Ocean Drilling Program Sites 1123, 1124, and 1125 off North Island of New Zealand in the southwest Pacific. Site 1124 showed opal contents ranging from approximately 2 to 8 wt%, which is relatively high compared to other sites. The subbottom maximum in biogenic opal content located between 1.0 and 1.5 m composite depth can be recognized at each site. Patterns of biogenic opal content in the uppermost parts of the cores appear to reflect the surface ocean settings relating to the migration of the Subtropical Convergence Zone.

Age models of ODP sites from the Barents Sea-Svalbard region

Based on a revised chronostratigraphy, and compilation of borehole data from the Barents Sea continental margin, a coherent glaciation model is proposed for the Barents Sea ice sheet over the past 3.5 million years (Ma). Three phases of ice growth are suggested: (1) The initial build-up phase, covering mountainous regions and reaching the coastline/shelf edge in the northern Barents Sea during short-term glacial intensification, is concomitant with the onset of the Northern Hemisphere Glaciation (3.6-2.4 Ma). (2) A transitional growth phase (2.4-1.0 Ma), during which the ice sheet expanded towards the southern Barents Sea and reached the northwestern Kara Sea. This is inferred from step-wise decrease of Siberian river-supplied smectite-rich sediments, likely caused by ice sheet blockade and possibly reduced sea ice formation in the Kara Sea as well as glacigenic wedge growth along the northwestern Barents Sea margin hampering entrainment and transport of sea ice sediments to the Arctic-Atlantic gateway. (3) Finally, large-scale glaciation in the Barents Sea occurred after 1 Ma with repeated advances to the shelf edge. The timing is inferred from ice grounding on the Yermak Plateau at about 0.95 Ma, and higher frequencies of gravity-driven mass movements along the western Barents Sea margin associated with expansive glacial growth.

Magnetostratigraphic age-depth tie points of ODP Leg 208 sites

We report the paleomagnetic and rock magnetic results from discrete sample analysis of sediments from Walvis Ridge, Leg 208 of the Ocean Drilling Program. In an effort to refine the shipboard magnetostratigraphy, alternating field and thermal demagnetization of discrete samples were carried out, predominantly on samples from Sites 1262 and 1267. Results are generally consistent with the shipboard pass-through cryomagnetometer data, though in some cases the discrete samples resolved ambiguities in the reversal record. Significantly, the C24r/C24n reversal boundary was identified at Sites 1262 and 1267, and most boundaries in the Paleocene and Upper Cretaceous sections are now identified to within 10-30 cm. Magnetic mineralogy results show that prior to the late Miocene, the predominant detrital magnetic component was coarse-grained magnetite and that after the late Miocene, titanomagnetite has also been present. This suggests a possible change in detrital source at that time.

Petrographic description and geochemistry of basalts and altered volcanic rocks from ODP Leg 183 sites

The basalts recovered during Legs 183 and 120 from the southern, central, and northernmost parts of the Kerguelen Plateau (Holes 1136A, 1138A, 1140A, and 747C, respectively), as well as those recovered from the eastern part of the crest of Elan Bank (Hole 1137A), represent derivates from tholeiitic melts. In the northern part of the Kerguelen Plateau (Hole 1140A), basalts may have formed from two sources located at different depths. This is reflected in the presence of both low- and high-titanium basalts. The basalts are variably altered by low-temperature hydrothermal processes (at temperatures up to 120°C), and some are affected by subaerial weathering. The hydrothermal alteration led mainly to the formation of smectites, chlorite minerals, mixed-layer hydromica-smectite and smectite-chlorite minerals, hydromica, serpentine(?), clinoptilolite, heulandite, stilbite, analcime, mordenite, thomsonite, natrolite(?), calcite, quartz, and dickite(?). Alteration of extrusive basalts is mainly related to horizontal fluid flow within permeable contact zones between lava flows. Under a nonoxidizing environment of alteration, the tendency to lose most of elements, including rare earth elements, from basalts dominates. Under on oxidizing environment, basalts accumulate many elements.

(Table T2) Sulfur isotopes of pore water from ODP Leg 201 sites

Fifty-seven interstitial water samples from six sites (Ocean Drilling Program Sites 1225-1229 and 1231) in the eastern equatorial Pacific Ocean and the Peru margin were analyzed for the stable sulfur isotopic composition (34S/32S) of dissolved sulfate along with major and minor ions. With the exception of Site 1231, sulfate from the interstitial fluids (d34S values as much as 89 per mil vs. the SF6-based Vienna-Canyon Diablo troilite standard) is found at depth to be enriched in 34S with respect to modern seawater sulfate (d34S = ~21 per mil), indicating that microbial sulfate reduction (MSR) took place to different extents at all investigated sites. Deeper sediments at Sites 1228 and 1229 are additionally influenced by diffusion of a sulfate-rich brine that has already undergone sulfate reduction. The intensity of MSR depends on the availability of substrate (organic matter), sedimentation conditions, and the active bacterial community structure. Formation of isotopically heavy diagenetic barite at the sulfate-methane transition zone is expected at Sites 1227 (one front), 1229 (two fronts), and probably Site 1228. At Site 1231, the constant sulfur isotopic composition of sulfate and concentrations of minor pore water ions indicate that suboxic (essentially iron and manganese oxide based) diagenesis dominates and no net MSR occurs.