Annotated record of the detailed examination of Mn deposits from the R/V Galathea II Danish Deep Sea Expedition, 1950-1952

The Danish Expedition of the "Galathea II" around the world brought important results concerning the marine organisms in the deep sea. The "Galathea II" showed not only different organisms of the Abyssal but for the first time of the deepest trenches of the western Pacific. Anton Bruun coined the term Hadal for the region below the Abyssal under 6000 m. Although the "Galathea II" aimed to investigate new deep sea regions beside the routes of former expeditions and to widen the horizon of knowledge relating marine organisms the technical equipment and the methodological approach had partly been developed earlier. The expedition of the "Galathea II" is part of a long tradition of cruises such as that of the British "Challenger", the German "Valdivia" and the Swedish "Albatross" and especially the Danish cruises of the "Dana I" and "Dana II" which happened some years before.

Chemical composition of bottom sediments and sedimentary rocks from the Pilippine Sea

Data on chemical composition of bottom sediments from some polygons in the Philippine Sea are reported. Areal and vertical variability of major and trace element contents in bottom sediments is analyzed for clarifying sedimentation features and diagenetic migration of the elements in the upper part of the sedimentary sequence.

(Table 1) Rates of biological activity in deep-sea sediments

Global maps of sulfate and methane in marine sediments reveal two provinces of subsurface metabolic activity: a sulfate-rich open-ocean province, and an ocean-margin province where sulfate is limited to shallow sediments. Methane is produced in both regions but is abundant only in sulfate-depleted sediments. Metabolic activity is greatest in narrow zones of sulfate-reducing methane oxidation along ocean margins. The metabolic rates of subseafloor life are orders of magnitude lower than those of life on Earth's surface. Most microorganisms in subseafloor sediments are either inactive or adapted for extraordinarily low metabolic activity.

Sea-surface reconstructions of the western Pacific Ocean during the last 5.3 million years

The late Neogene was a time of cryosphere development in the northern hemisphere. The present study was carried out to estimate the sea surface temperature (SST) change during this period based on the quantitative planktonic foraminiferal data of 8 DSDP sites in the western Pacific. Target factor analysis has been applied to the conventional transfer function approach to overcome the no-analog conditions caused by evolutionary faunal changes. By applying this technique through a combination of time-slice and time-series studies, the SST history of the last 5.3 Ma has been reconstructed for the low latitude western Pacific. Although the present data set is close to the statistical limits of factor analysis, the clear presence of sensible variations in individual SST time-series suggests the feasibility and reliability of this method in paleoceanographic studies. The estimated SST curves display the general trend of the temperature fluctuations and reveal three major cool periods in the late Neogene, i.e. the early Pliocene (4.7 3.5 Ma), the late Pliocene (3.1-2.7 Ma), and the latest Pliocene to early Pleistocene (2.2-1.0 Ma). Cool events are reflected in the increase of seasonality and meridional SST gradient in the subtropical area. The latest Pliocene to early Pleistocene cooling is most important in the late Neogene climatic evolution. It differs from the previous cool events in its irreversible, steplike change in SST, which established the glacial climate characteristic of the late Pleistocene. The winter and summer SST decreased by 3.3-5.4°C and 1.0 2.1C in the subtropics, by 0.9°C and 0.6C in the equatorial region, and showed little or no cooling in the tropics. Moreover, this cooling event occurred as a gradual SST decrease during 2.2 1.0 Ma at the warmer subtropical sites, while that at cooler subtropical site was an abrupt SST drop at 2.2 Ma. In contrast, equatorial and tropical western Pacific experienced only minor SST change in the entire late Neogene. In general, subtropics was much more sensitive to climatic forcing than tropics and the cooling events were most extensive in the cooler subtropics. The early Pliocene cool periods can be correlated to the Antarctic ice volume fluctuation, and the latest Pliocene early Pleistocene cooling reflects the climatic evolution during the cryosphere development of the northern hemisphere.

(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.