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Abstract:We have applied the sequential extraction procedure developed by the Community Bureau of Reference (BCR) to eight Japanese geochemical reference materials. By using this method, we attempt to extract exchangeable and carbonate phases in step 1, extract iron hydroxide and manganese oxide in step 2, and extract metal sulfide and organic material in step 3. We use X-ray diffractometry (XRD) to measure untreated samples and the residue of samples after each step of the extraction process to determine whether the target material is satisfactorily decomposed during the procedure. For JSd-1 and JSd-3, XRD patterns do not change significantly by using the BCR procedure. Actually, most of the elements in these materials are scarcely extracted by BCR scheme. The peaks of calcite in JSd-4, JMs-1 and JMs-2 disappear in the XRD patterns after the first extraction procedure. The result suggests that the target phase of step 1 process is fully decomposed. JLk-1 and JMs-2 show high concentrations of the Fe and Mn extracted in step 2. However, it is difficult to clearly confirm the full decomposition of iron hydroxide and manganese oxide in step 2 because these materials do not show distinct peaks in the XRD patterns. Pyrite in JMs-1 disappears in step 3 of the extraction, which suggests that sulfide is satisfactorily decomposed in this process. X-ray reflection intensities of some peaks for quartz and plagioclase in JSO-1 increase significantly after step 3 of the extraction. It is assumed that organic material thickly covered the mineral surfaces and reduced the X-ray reflection from the minerals prior to the third procedure. Although this evidence is indirect, we conclude that organic material is successfully decomposed and removed from the mineral surface during the third extraction procedure. On the basis of these results, it is confirmed that the BCR protocol can properly extract target materials from the geochemical reference materials.

The contents of total carbon, hydrogen, nitrogen and sulfur in twenty‐seven geological reference materials, issued by five producer organisations (USGS, CCRMP, ANRT, NIST and GSJ) were determined using an automated simultaneous elemental analyser following combustion. In order to complete gasification of C and N in some geological materials, the combustion temperature needed to be greater than 1150 °C. The calibrator prepared from known amounts of reagent material was not adopted for more than 1.2% m/m of H. Unrealistically high values in certain materials supposed to contain less than 1000 μg g−1 S may be due mainly to memory effects. The limit of detection was 50 μg g−1 for C and N, 500 μg g−1 for H and 1000 μg g−1 for S. Although the blank value of C and N was always stable and less than one third of the detection limit, it had a slightly higher value for N and S. By repeating long‐term analysis, high reproducibility for each of the four elements was verified. The method has been applied satisfactorily to a variety of geological reference materials, and recommended values for C, H and N for most of the reference materials studied have been tabulated.

Copper speciation in a collection of Japanese geochemical reference materials (JSO‐1, JLk‐1, JSd‐1, ‐2, ‐3 and ‐4, JMs‐1 and JMs‐2) was achieved by sequential extraction and characterised using X‐ray absorption near‐edge structure spectroscopy. In the first step of the extraction, referred to as the acid fraction, between 1% and 20% total Cu within the reference materials was extracted. Such a result is typically accounted for by absorption of Cu onto clay minerals. However, the presence of Cu sulfate (an oxidation product of chalcopyrite) was observed in some of the stream sediments affected by mining activity (JSd‐2 and JSd‐3) instead. Copper was extracted in the reducible fraction (targeting Fe hydroxide and Mn oxide) (2–49% total Cu). Between 2% and 51% Cu was extracted in the oxidised fraction (targeting sulfides and organic matter). X‐ray absorption near‐edge structure spectroscopy clarified that the reducible fraction consisted of Cu bound to Fe hydroxide, whereas the oxidised fraction was a mixture of Cu bound to humic acid (HA) and Cu sulfide. In the oxidisable fraction, chalcopyrite was the predominant species identified in JSd‐2, and Cu bound to HA was the major species identified in JSO‐1 (a soil sample).

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In order to characterize the variation of elemental concentrations according to the grain size classification, a total of 795 river and marine sediments were analyzed for major and minor constituents. Almost all the constituents of the river sediments are enriched more in the fine fractions than in the coarse ones, but both K and Ba are often abundant in the coarse fraction of sediments. The K and Ba abundant coarse sediments are commonly derived from the felsic rocks containing a large amounts of potassium feldspar. In the case of some muddy river sediments collected in the plain areas, somehow P, Cu, Zn and C are enriched more in the coarse fraction than in the middle fraction of sediments. In this case, the coarse sediment particles consist mainly by the nodules which composed of small clastic materials, clay minerals and biogenic materials. Although most constituents of the marine sediments are also much dominant in the fine fraction than in the coarse one, Ca, Sr and As are generally enriched in the coarse grain sediments distributed in relatively shallower water depth. There is no clear increasing or decreasing tendency in the abundance of Fe, Co, Ce, U and Y according to the grain size classification. High concentrations more than five times over background abundance are found for Mn and Mo in the fine sediments collected in the deeper water depth of the Japan Sea. The significant amounts of Ca and Sr in the coarse marine sediments are derived from the calcareous materials such as shell and coral fragments and/or calcareous algae. The anomalous behavior of As, Fe, Co, Ce, U, Y, Mn or Mo concentration according to the grain size classification may be caused by the process of weathering and diagenesis in the marine environments.

Total (T-) Fe 2 O 3 (全鉄量をFe 2 O 3 に換算したもの)) といく つかの微量元素 (Li，Be，Sc，V，Cr，Co，Ni，Cu，Zn， Rb，Sr，Y，Mo，Ba，Pb) を分析した結果と化学組成の 特徴について報告する． ２．試料処理及び分析方法 K-グラブ採泥器で採取された試料のうち，表層部 0 -3 cmを適量分取した．礫質の堆積物試料については，可 能な限り付随する細粒の堆積物を分取した．試料を室温 で乾燥した後，石川式めのう粉砕機で約 80 メッシュ (約 180 µm) 以下に粉砕して分析試料とした．粉砕した試料 0.2 gを硝酸3 ml，過塩素酸2 ml，フッ化水素酸5 mlの混酸 を用いて，120 ℃で2時間加熱して分解後，さらに145 ℃ で1時間加熱分解を行った．その後，200 ℃以下で蒸発乾 固した後，7M硝酸 5 mlを加えて加温溶解し，No.5cの