The D/H fractionation factors between the crystal water of copper chloride dihydrate and a saturated aqueous solution of copper(II) chloride, α_CW-st.sol, and between the saturated aqueous solution and water vapor, α_st.sol-V, were experimentally determined at 25°C in equilibrium. The observed values of α_CW-st.sol and α_st.sol-V, were 0.950 ± 0.002 and 1.052 ± 0.001, respectively. The D/H fractionation factor between the crystal water of copper chloride dehydrate and water vapor in equilibrium, α_CW-V, was calculated to be 0.999 ± 0.002 from the observed values of α_CW-st.sol and α_st.sol-V, and is used to discuss D/H fractionation in crystal water of crystalline hydrates. It is shown that such D/H fractionation is better expressed by α_CW-V than by the conventionally used fractionation factor between crystal water and mother liquor, α_CW-st.sol, because α_CW-V represents the activity ratio, whereas α_CW-st.sol is simply the concentration ratio. Based on the results in this study, we consider that the coordination bond between divalent cupreous ions and oxygen atoms in water molecules and the hydrogen bond between crystal water and chlorine ions contribute substantially to the fractionation of hydrogen isotopes.

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The D/H fractionation factor between crystal water in copper chloride dihydrate and water vapor was calculated from Raman spectral data for single crystals of CuCl₂2H₂O and CuCl₂2D₂O based on statistical mechanics. Single crystals of CuCl₂2H₂O and CuCl₂2D₂O were synthesized from supersaturated solutions of pure H₂O and 99.75% D₂O at 25°C. The calculations were made for 25°C using the reduced partition function ratio (RPFR) for gaseous equilibrium, which was assumed to be valid for crystal water-water vapor system in equilibrium. Published H₂O and D₂O spectroscopic data were used to calculate the RPFR for water vapor molecules. The D/H fractionation factor calculated using the 22 observed vibrational frequencies was 0.936, which is less than the experimental value of 0.999 ± 0.002 by about 6%. Including estimations of the two unobserved librational frequency ratios, the calculated value became 1.014, which is closer to the experimental value, indicating that contribution of librations is not negligible, though smaller than that of the stretching and bending vibrations.

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In order to investigate the chemical form of authigenic phosphate compounds being precipitated in coastal sediments, the vertical distributions of dissolved phosphate and fluoride in pore water from the sediments of Funka Bay (Japan) were determined for the period from April 1997 to July 1998. The phosphate concentration in surface sediment pore water was typically 0–5 μM and increased up to 40–60 μM at 70 cm depth below the surface. In spring and summer, small maximums higher than 100 μM were found at a depth of around 20 cm, probably resulting from decomposition of organic matter and/or desorption of phosphate from the ambient sediment particles under anoxic conditions. Seasonal and vertical variations in the fluoride concentration of the pore water were in the range 5–74 μM. We found an inverse relationship between interstitial phosphate and fluoride concentrations, suggesting precipitation of an authigenic fluoro-phosphorus compound with a P/F atomic ratio of around 1/3 in the sediment. Formation of such a compound will greatly contribute to the global sink of phosphate from the ocean.

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We report in situ ion microprobe U-Th-Pb dating of an index fossil conodont derived from Langkawi Island, northern Malaysia. Fifteen spots on five fragments of an early Silurian conodont yield ²³²Th-²⁰⁸Pb* isochron age of 429 ± 50 Ma (2σ, MSWD = 0.95). The ²³⁸U-²⁰⁶Pb* isochron age of 436 ± 270 Ma (2σ, MSWD = 0.47) has a large uncertainty, since the ²³⁸U abundance is significantly small, but the age is comparable to that of ²³²Th-²⁰⁸Pb*. These ages are consistent with the depositional and early diagenetic ages of the fossil in a Llandoverian sedimentary sequence (430–439 Ma). The success of the method depends on the heterogeneity of diagenetically incorpolated Th in a hundred μm size and the consequent variations in Pb isotopic compositions due to radioactive decay. Shale-normalized rare earth element (REE) abundance shows a concave pattern with middle REE enrichment. There is not a significant anomaly of Ce and Eu. These characteristics are different from those of a Carboniferous conodont, probably due to a different formation environment as suggested by other workers.

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The Dahongshan kimberlite field in Hubei Province, China, is situated in the northern margin of the Proterozoic Yangtze Craton. The kimberlites erupted in the Paleozoic (ca. 326 Ma), some of which are associated with barren lamproites. An unusually fresh garnet lherzolite collected from this kimberlite field provides an opportunity to directly study the nature of the Paleozoic lithospheric mantle beneath the Yangtze Craton. The lherzolite is moderately depleted in major element compositions (2.66wt% Al₂O₃, 2.82wt% CaO, and 90.9 Mg#), with a forsterite content in olivine around 90.5%. The rare earth element characteristics of the whole rock [(La/Sm)_N = 13 and (Eu/Yb)_N = 0.48] and of the constituent minerals such as clinopyroxene [(La/Yb)_N = 61] reveal that at least two processes were recorded in the lherzolite: depletion followed by enrichment. Depletion process was derived from low degree of partial melting, as demonstrated by relatively high NiO contents (0.50%) in olivines and PPGE-enriched mantle-normalized PGE pattern of the whole rock. The enrichments in LREE and LILE are attributed to melt infiltration that must be an event prior to the kimberlite eruption as constrained by trace element and Sr-Nd isotopic data. The Rb-Sr and Sm-Nd data constrained an age of about 510 Ma, which is much older than the age of kimberlite eruption, but consistent with the eruption time of diamond-bearing lamproites on the centre of the Craton. The stable Gt-Opx-Cpx mineral assemblage gives a T-P estimation of 1042°C and 34 kbar, corresponding to 110 km depth, well within the graphite stability field. The geotherm inferred from this lherzolite was much higher than the typical cratonic geotherm (40 mW/m²), but still lower than the oceanic geotherm. Thus, our study and previous data demonstrate that the lithospheric mantle beneath the Yangtze craton was less depleted and was hotter in Paleozoic than the lithospheric mantle beneath typical old Cratons, i.e., the Kaapvaal, the Siberia, and the North China.

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Organic ligands for copper(II) were isolated from lake waters in Lake Biwa and its river waters by immobilized metal ion affinity chromatography (IMAC), and were characterized by three-dimensional excitation/emission matrix spectroscopy (3DEEM) and fluorescence quenching titration. The results show that the contribution of total organic ligands was 0.63–4.68% of the bulk dissolved organic matter (DOM), in terms of UV absorbance, in lake and river waters. Three characteristic excitation/emission (Ex/Em) fluorescence peaks were identified in organic ligands from both lake and river waters, at Ex/Em 310–330/374–434 nm (Peak A), 250/414–454 nm (Peak B), and 260–270/306–330 nm (Peak C). Peaks A and B were referred to as humic-like fluorescence, Peak C as protein-like fluorescence. All Ex/Em maxima of organic ligands in lake waters were shifted towards shorter wavelength, and the fluorescence intensities were higher than those in river waters. The results of fluorescence quenching titration show that the IMAC ligands were weak ligands, with conditional stability constants (log K′_CuL) around 7.27 for river ligands, and 7.84–9.23 for lake ligands. The differences of fluorescence properties indicate the variability of fluorescent ligands between river terrestrial and lake aquatic environments.

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Although the rare earth element (REE) geochemistry of hydrothermal systems have intensively been investigated at mid-oceanic ridges, studies are relatively few at the converging plate zones like the Okinawa Trough. The “chimney” deposits obtained by using submersible “SHINKAI 2000” from the Iheya Ridge site, Okinawa Trough are largely composed of massive carbonates and silicates with minor amounts of sulfides, and appear black and white depending upon their composition. The concentrations of REEs are 2–3 orders of magnitude higher in the sulfide-rich black portion than in the white portion. Both deposits show a pronounced positive Eu anomaly and the light REE enrichment which are characteristic of the high-temperature fluids venting from sediment-free oceanic ridges. Whilst the Okinawa Trough REE data are unique in the hydrothermal vent systems in having a flat chondrite-normalized pattern for the REEs heavier than Tb. The Eu-anomaly is greater in the white deposit than in the black deposit, suggesting that Eu²⁺ is more mobile (resistant to scavenging by sulfides) than stricktly trivalent REEs in the hydrothermal solution and may be incorporated into the former by substitution of Sr²⁺ in the calcite lattice. The Calyptogena shell shows the REE pattern typical for seawater without any positive Eu anomaly, suggesting that the influence of hydrothermal solution is negligible. Although the light REE concentrations are comparable, the heavy REEs are significantly higher in the shell than in the white deposit. This suggests that the concentrations of the heavy REEs in the carbonate-forming hydrothermal solution may be lower than those of ambient seawater. Thus, the hydrothermal system in the Okinawa Trough may not be a source but a sink for dissolved REEs in seawater.

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Dissolved organic carbon (DOC) in the Sea of Japan was determined by the high temperature catalytic oxidation (HTCO) method. The chemical parameters related to DOC, i.e., the three-dimensional excitation-emission matrix spectrum, nutrients, chlorophyll a, dissolved oxygen and monosaccharides concentration were also determined. The vertical distribution of DOC in the northernmost sampling site (CM10; 44.1°N, 138.6°E) was not like that those in other sampling sites. An anomalously high DOC concentration was observed for the middle layer (250 to 1000 m) at CM10, which was two or three times higher than the concentration for the same layer at other sampling sites. Moreover, dissolved oxygen, nutrients and fluorescence intensity of marine humic-like substances were also unusual for the middle layer of CM10, compared to the same layer at other sampling sites. The amounts of Chl. a and monosaccharides between the surface and 100 m depth at CM10 were larger than those of other sampling sites. In the middle layer, the water mass structure of CM10 differed from that of other sampling sites. These results suggested that the cause of the DOC distribution anomaly at CM10 could be considered as due to the inflow of quite different water mass with incomplete oxidation of organic matter.

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Maleimides were detected in organic solvent extracts and chromic acid oxidation products of the Cretaceous/Tertiary boundary sediments at Kawaruppu. Free (organic solvent extractable) maleimides consisted of 2, 3-dimethylmaleimide and 2-methyl-3-ethylmaleimide, and bound (oxidatively extractable) maleimides of 2-methylmaleimide and its 3-n-alkyl homologs up to C₄, benzomaleimide (phthalimide) and its methyl homologs. The total concentrations of free and bound maleimides ranged from n.d. to 10 and from 4 to 49 nmol g^-1, respectively. The most abundant compound was 2-methyl-3-ethylmaleimide both in free and bound forms in all the sediments, indicating that the maleimides detected were very likely degradation products of porphyrins and/or chlorophylls. The concentrations of both forms of alkylmaleimides were significantly smaller in the boundary claystone than the sediments above and below it. Their depth profiles agreed with those of pristane plus phytane and n-alkanes, indicating smaller inputs of chlorophylls into the claystone, which relates to the large bio-mass extinction at the end of Cretaceous. The Kawaruppu sequence afforded the first case in which 2-methylmaleimide was the second most abundant maleimide, indicating a mild thermal history of the sediments. The ratios of 2, 3-dimethyl- to 2-methyl-3-ethylmaleimide of both free and bound forms showed constant values above and below the boundary claystone, reflecting the uniform diagenesis experienced by the sediments. The ratios exhibited larger values within the claystone, which is possibly related to different precursor chlorophylls caused by the massive extinction of organisms.

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We have been able to reconstruct the changes that have occurred in the phytoplankton community of Lake Baikal over the past 2.8 million years (Ma) by measuring the abundance of residual steryl chlorin esters (SCEs) in the 0–100m section of the 600 m long BDP98 sediment core. The sterol composition of SCEs showed remarkable variations among interglacial periods, and green algae and dinoflagellates, apart from diatoms, had been abundant in Lake Baikal until 1.2 Ma ago.

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