(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.

Appendix A: LA-ICP-MS results (Laser-ablation inductively coupled plasma mass spectrometer) from monazite Moacir standard

Three samples of garnet-kyanite paragneiss from the Variscan Ulten Zone (Northern Italy) were studied in detail for U-Th-Pb monazite dating. Monazite in these gneisses is abundant, shows highly variable grain size and occupies different textural positions: within the matrix, as inclusion in garnet and kyanite, within apatite aggregates. Monazite shows different deformation features as a function of the textural position: enclosed (shielded) monazite is generally more fractured than matrix (unshielded) monazite. The integration of textural information with deformation features and in situ U-Th-Pb analyses by LA-ICP-MS indicates that there is no direct correlation between textural site and monazite ages. Old ages of 351-343 Ma, determined on portions of large matrix (unshielded) monazite and on rare domains of monazite shielded by garnet, have been related to a prograde stage of the Variscan metamorphic evolution of the Ulten Zone. Ages of 330-326 Ma, which are related to the thermal peak, are recorded by small matrix monazite, external domains of large matrix monazite, and by (domains of) fractured monazite enclosed in garnet and kyanite. Large, old unshielded grains formed as blasts during the prograde metamorphic history and survived the peak metamorphism during which crystallisation/re-crystallisation partially occurred.

Geochemical and palynological results of IODP Hole 302-M0004A from Lomonosov Ridge, Arctic Ocean

Several episodes of abrupt and transient warming, each lasting between 50,000 and 200,000 years, punctuated the long-term warming during the Late Palaeocene and Early Eocene (58 to 51 Myr ago) epochs**1,2. These hyperthermal events, such as the Eocene Thermal Maximum 2 (ETM2) that took place about 53.5 Myr ago**2, are associated with rapid increases in atmospheric CO2 content. However, the impacts of most events are documented only locally**3,4. Here we show, on the basis of estimates from the TEX86' proxy, that sea surface temperatures rose by 3-5 °C in the Arctic Ocean during the ETM2. Dinoflagellate fossils demonstrate a concomitant freshening and eutrophication of surface waters, which resulted in euxinia in the photic zone. The presence of palm pollen implies**5 that coldest month mean temperatures over the Arctic land masses were no less than 8 °C, in contradiction of model simulations that suggest hyperthermal winter temperatures were below freezing**6. In light of our reconstructed temperature and hydrologic trends, we conclude that the temperature and hydrographic responses to abruptly increased atmospheric CO2 concentrations were similar for the ETM2 and the better-described Palaeocene-Eocene Thermal Maximum**7,8, 55.5 Myr ago.

Salinity of the Eocene Arctic Ocean from oxygen isotope analysis of fish bone carbonate

Stable isotope analysis was performed on the structural carbonate of fish bone apatite from early and early middle Eocene samples (~55 to ~45 Ma) recently recovered from the Lomonosov Ridge by Integrated Ocean Drilling Program Expedition 302 (the Arctic Coring Expedition). The d18O values of the Eocene samples ranged from -6.84 per mil to -2.96 per mil Vienna Peedee belemnite, with a mean value of -4.89 per mil, compared to 2.77 per mil for a Miocene sample in the overlying section. An average salinity of 21 to 25 per mil was calculated for the Eocene Arctic, compared to 35 per mil for the Miocene, with lower salinities during the Paleocene Eocene thermal maximum, the Azolla event at ~48.7 Ma, and a third previously unidentified event at ~47.6 Ma. At the Azolla event, where the organic carbon content of the sediment reaches a maximum, a positive d13C excursion was observed, indicating unusually high productivity in the surface waters.

(Table 1) Sulphur concentration and isotopic composition of ODP Leg 126 igneous rocks

Sulfur isotope ratios have been determined in 19 selected igneous rocks from Leg 126. The d34S of the analyzed rocks ranges from -0.1 â to +19.60 â. The overall variation in sulfur isotope composition of the rocks is caused by varying degrees of seawater alteration. Most of the samples are altered by seawater and only five of them are considered to have maintained their magmatic sulfur isotope composition. These samples are all from the backarc sites and have d34S values varying from +0.2 â to +1.6 â, of which the high d34S values suggest that the earliest magmas in the rift are more arc-like in their sulfur isotope composition than the later magmas. The d34S values from the forearc sites are similar to or heavier than the sulfur isotope composition of the present arc.