(Table 1) Summary of magnetic properties and chemical composition of opaque minerals in DSDP Leg 58 Holes basallts

The Curie temperature and thermomagnetic behavior of wholerock samples were measured in basalts recovered from Sites 442, 443, and 444 of DSDP Leg 58 in the Shikoku Basin, and from Site 446 in the Daito Basin, north Philippine Sea. Chemical composition and microscopic features of opaque oxides in the same samples were also investigated. Degree and mode of oxidation of titanomagnetite vary irrespective of site, lithology, or magnetic polarity, and no systematic correlation has been found between any two of these characteristics. Magnetic properties are systematically different between massive flows recovered at Hole 444A (Shikoku Basin) and Hole 446A (Daito Basin), although the controlling factor is unknown.

Geochemistry on water profiles from the Kara Sea

As a part of the Russian-German project "Siberian River-Runoff (SIRRO)" the major element composition of the dissolved load and the major and trace element composition of particulate load and bottom sediment of the Yenisei River and Estuary were analyzed and examined in context of the basin lithology and climate. In addition, the processes controlling the transformation of the river load in the estuarine mixing zone were investigated. The chemical composition of the dissolved and particulate load of the Yenisei fluvial endmember is generally comparable to that of other major world rivers. The dissolved load is chiefly controlled by carbonate weathering and the chemical composition of the river suspended particulate matter (SPM) is similar to that of the North American Shale Composite (NASC), which represents the weathering product of the upper continental crust. The Chemical Index of Alteration (CIA) of the Yenisei SPM amounts to 71, which indicates moderate chemical weathering. With regard to the SPM geochemistry, the Yenisei occupies an intermediate position between the adjacent rivers Khatanga and the Lena. Drastic changes in the composition of the river load are seen in the mixing zone between fresh and salt water. While dissolved Na, Ca, Mg, K, CI, S04, F, Br, Sr and HC03 behave conservatively, dissolved Fe is completely removed from solution at very low salinities. Particulate Mn exhibits a pronounced mid-salinity minimum concomitant with a maximum of dissolved Mn, which is probably related to suboxic conditions in the area of the so-called "marginal filter", where highest turbidities are found. The Mn-minimum in SPM is paralleled by depletions of the elements Ba, Zn, Cd, Ni, Cu and V, which can be associated with manganese particles. The estuarine bottom sediments are composed of mud and sand and the sedimentological parameters of the bottom sediments have to be considered for the interpretation of the bulk geochemical data. The chemical composition of the mud is comparable to the SPM, whereas the sand is relatively enriched in Si/Al, Ba/Al, Zr/Al and Sr/Al ratios and depleted in transition metals.

H, O, Sr, and Nd isotope ratios and water, Rb, Sr, Sm, and Nd content of ODP Hole 116-717C and 116-718C samples (Table 2)

Mineralogical and H, O, Sr, and Nd isotope compositions have been analyzed on a set of representative samples from the 17-m.y. section in ODP Leg 116 Holes 717C and 718C. Based on the mineralogical composition of the fraction <2 µm together with the lithogenic-biogenic composition of the fraction >63 µm, the whole section can be subdivided into three major periods of sedimentation. Between 17.1 and 6 m.y., and between 0.8 m.y. to present, the sediments are characterized by sandy and silty turbiditic inputs with a high proportion of minerals derived from a gneissic source without alteration. In the fraction <2 µm, illite and chlorite are dominant over smectite and kaolinite. The granulometric fraction >63 µm contains quartz, muscovite, biotite, chlorite, and feldspars. The 6-to 0.8-m.y. period is represented by an alternation of sandy/silty horizons, muds, and calcareous muds rich in smectite, and kaolinite (50% to 85% of the fraction <2 µm) and bioclastic material. The presence of smectite and kaolinite, as well as the 18O/16O and the 87Sr/86Sr ratios of the fraction <2 µm, imply an evolution in a soil environment and exchanges with meteoric ground water. The ranges of isotopic compositions are limited throughout the section: d18O quartz = 11.7 to 13.3 per mil, 87Sr/86Sr = 0.733 to 0.760 and epsilon-Nd (0) = -17.4 to -13.8. These values are within those of the High Himalaya Crystalline series, and they are considered to reflect this source region. The data imply that, since 17 Ma, this formation has supplied the major part of the eroded material.

(Table 1) Percentage of non-opaque heavy minerals, heavy residue, magnetite, and opaque heavy minerals, DSDP Sites 58-445 and 58-446

Heavy-mineral analyses were made for 39 samples, 27 from DSDP Site 445 and 12 from Site 446. About one-fourth of the samples were so loose that they were easily disaggregated in water. The amount of heavy residue and the magnetite content of the heavy fraction were very high, 0.2 to 44 per cent and (on the average) more than 20 per cent, respectively. Among the non-opaque heavy minerals, common hornblende (0 to 80%) and augite (0 to 98%) are most abundant. Pale-green and bluish-green amphiboles (around 10%) and the epidote group (a few to 48%) are next in abundance. Euhedral apatite and biotite and irregularly shaped chromite are not abundant, but are present throughout the sequence. Hacksaw structure is developed in pale-green amphibole and augite. At Site 445, a fair amount of chlorite and a few glauconite(?) grains are present from Core 445-81 downward. The content of common hornblende and opaque minerals also changes from Core 445-81 downward. A geological boundary may exist between Cores 445-77 and 445-81. Source rocks of the sediments at both sites were basaltic volcanic rocks (possibly alkali suite), schists, and ultramafic rocks. The degree of lithification and amount of heavy residue, and the content of magnetite, non-opaque heavy minerals (excluding mafic minerals), and mafic minerals in the cores were compared with Eocene, Oligocene, and Miocene sandstones of southwest Japan. In many respects, the sediments at Sites 445 and 446 are quite different from those of southwest Japan. From the early Eocene to the early Miocene, the area of these sites belonged to a different geologic province than southwest Japan.