巻号一覧
43 巻 (2009)
- 6 号 p. 395-
- 5 号 p. 293-
- 4 号 p. 217-
- 3 号 p. 143-
- 2 号 p. 65-
- 1 号 p. 1-
43 巻, 3 号
選択された号の論文の6件中1～6を表示しています
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KAZUYA TANAKA, YOSHIO TAKAHASHI, HIROSHI SHIMIZU2009 年 43 巻 3 号 p. 143-149
発行日: 2009/06/20
公開日: 2011/04/19
ジャーナル フリーThe Y K-edge X-ray absorption near-edge structure (XANES) spectra of various materials were measured to investigate whether rare earth elements (REEs) are incorporated in carbonate phase or in other minor phases such as Fe-Mn oxides and phosphate within limestone. As reported in our previous work, a white line peak specific to synthetic Y-doped calcite is observed in the Y K-edge XANES spectrum. Natural limestone and dolomite samples show XANES spectra similar to that of the Y-doped calcite. The similarity of XANES spectra between natural and synthetic carbonates strongly indicates that Y is incorporated into the carbonate phase of natural samples, and that local coordination structures of Y in natural and synthetic carbonates are the same. Previous work reported a difference of local coordination structure between light and heavy REEs. Furthermore, we reported that local coordination structures of Y and Ho are similar. The results of this study therefore demonstrate that the Y K-edge XANES spectrum can be used as a fingerprint to trace heavy REEs including Y in natural carbonate. The information that REEs are not distributed to other minor phases is an important basis for the use of limestone to estimate REE pattern of ancient seawater coupled with the REE partition coefficient data between seawater and carbonate.抄録全体を表示PDF形式でダウンロード (915K) -
JIN-LIANG FENG, ZHI-JIU CUI, LI-PING ZHU2009 年 43 巻 3 号 p. 151-166
発行日: 2009/06/20
公開日: 2011/04/19
ジャーナル フリーThe origin of terra rossa and its relationship with its underlying carbonate rocks pose long-standing and controversial questions. This study focuses on one 5.4 m thick terra rossa profile on dolomite. The authors examined the quartz content, size distribution of quartz grains, mineral composition, surface micro-texture and crystal morphology of quartz, oxygen isotope ratios of quartz, and other tracers in the terra rossa and underlying dolomite to determine the derivation of terra rossa. The results indicate that terra rossa in the Dashandong profile on the Yunnan-Guizhou Plateau, China, is an in situ weathering solum. The terra rossa originates mostly from insoluble residues of the parent dolomite. The debris minerals (quartz and feldspar) derive completely from the parent dolomite. The clay minerals, and Al, Fe and Mn oxides and hydroxides likely have three origins. One portion derives from insoluble residues of the parent dolomite. A second portion converts from primary minerals in the parent dolomite. The last contribution comes from authigenic minerals from aqueous solutes transported by the water cycle. Authigenic minerals constitute the main components of the terra rossa. During weathering processes, the dolomite weathering functions as a “trap” against the escape of in situ insoluble residues and external aqueous solutes by means of poly-genetic chemical and physical barriers.抄録全体を表示PDF形式でダウンロード (5028K) -
ZIJUN WU, LINXI YUAN, NAN JIA, YUHONG WANG, LIGUANG SUN2009 年 43 巻 3 号 p. 167-177
発行日: 2009/06/20
公開日: 2011/04/19
ジャーナル フリーThe biogeochemcical reactions responsible for fossilized minerals preservation in ancient geological conditions are very often debatable, because little is known about the in situ processes at geo-historical period. In the present study, we describe the formation of iron ores collected in the intertidal zone of the Zhujiajian Island, Zhoushan Archipelago in the East China Sea. Morphological, mineralogical and geochemical analyses were performed on the iron ores and the surrounding geological materials. The results show that the iron ores, composed of spherical ferrihydrite and fibrous aggregates of goethite, presented morphological characteristics reminiscent of bacterial activity. The biominerization process in the seepage system is believed to represent an analogue mechanism for the biogenic formation of iron ores. The degradation of the ancient wood layer provided humic substances which accelerated the leaching process of iron from the surrounding bedrock and soils. The abundant leaching iron not only provided the sufficient iron material source, but also created the ideal conditions for the survival of the iron-oxidizing bacteria. The presence of Leptothrix-like sheaths and Gallionella-like stalks in the present-day seepage environment promoted the oxidization of Fe2+ to Fe3+ and the rapid precipitation of bacteriogenic iron oxides (BIOS) on bacterial sheaths and stalks, allowing the preservation of the morphological characteristics of the bacteria. As time went by, the amorphous biomineralization product (ferrihydrite) can further transfer to more crystalline goethite and therefore be preserved in the ores permanently, representing as the imprints of bacterial activity during the formation of iron ores. The present findings should help elucidate the role of bacteria in the formation of biogenic iron ores in different environments during geo-historical context.抄録全体を表示PDF形式でダウンロード (1437K) -
SOU N. MATSUNAGA, ALEX B. GUENTHER, JIM P. GREENBERG, MARK POTOSNAK, M ...2009 年 43 巻 3 号 p. 179-189
発行日: 2009/06/20
公開日: 2011/04/19
ジャーナル フリーBiogenic emission of sesquiterpene (SQT) and oxygenated SQT (OSQT) were measured from the dominant vegetation in a desert shrubland and urban area (Las Vegas, Nevada, U.S.A.), and at temperate forest sites at Niwot Ridge, Colorado, U.S.A., Tomakomai, Hokkaido, Japan and Tumbarumba, New South Wales, Australia. Additional measurements were conducted using greenhouse grown plants. The sampling technique, based on solid adsorbent preconcentration and liquid extraction, is suitable for measuring high molecular weight and low volatility compounds such as OSQTs. Fourteen SQT and OSQT (10 SQT and 4 OSQT) were identified in the field experiments. Total emission rates of SQTs and OSQTs varied from the detection limit to 7.6 μgC g-1h-1 (average: 0.74) and 3.7 μgC g-1h-1 (average: 0.31), respectively, and varied with plant species and location. Environmental conditions, including temperature and precipitation, appeared to influence emission rates. Canopy level emission of SQT and OSQT in Tomakomai were also estimated using an emission model. The emission rate of SQT and OSQT ranged from 72 to 710 μgC m-2h-1 (average, 460 in daytime) and from 38 to 370 μgC m-2h-1 (average, 240 in daytime), respectively. Their contributions can be very high in specific regions and seasons. Given the relatively high reactivity and secondary organic aerosol yields of SQTs and OSQTs, it is likely that these compounds influence atmospheric constituents in at least some areas.抄録全体を表示PDF形式でダウンロード (2906K) -
TOMOAKI MORISHITA, SHOJI ARAI, YOSHITO ISHIDA, AKIHIRO TAMURA, FERNAND ...2009 年 43 巻 3 号 p. 191-206
発行日: 2009/06/20
公開日: 2011/04/19
ジャーナル フリーMultiple trace-element compositions of clinopyroxene and garnet in aluminous mafic layers (±corundum and/or sapphirine) alternating with peridotites from the Ronda massif, Spain, were determined by an ArF 193 nm excimer laser system coupled with a quadrupole ICP-MS. The studied aluminous mafic rock is divided into several sublayers based on the modal mineral variations. Trace-element compositions of minerals vary between sublayers. Primitive mantle-normalized trace-element distribution patterns have more significant positive Eu anomaly for both garnet and clinopyroxene in the corundum-bearing sublayers than for those in the other sublayers whereas corundum-bearing sublayers contain more abundant secondary plagioclase than corundum-free sublayers. These geochemical signatures of the corundum-bearing sublayers intercalated with corundum-free sublayers were acquired as plagioclase-rich portions of gabbroic layered sequence originated at the lower crustal to the uppermost mantle sections rather than selective accumulation of metamorphic plagioclase due to deformation during the late stage of exhumation of the massif. Partition coefficients of trace elements between clinopyroxene and garnet show systematic variations with respect to major element composition, indicating local attainment of chemical equilibrium. The trace element compositions of clinopyroxene and garnet were equilibrated with secondary metamorphic plagioclase, i.e., at granulite-facies conditions, because plagioclase is required for the geochemical balance in Sr and Eu contents of the whole-rock trace element compositions. Positive Eu anomaly of clinopyroxene (±garnet) is also found in mantle-derived aluminous eclogitic xenoliths and eclogitic mineral inclusions in diamond captured in kimberlites, and is thus a useful indicator to explore recycled crustal components in the mantle.抄録全体を表示PDF形式でダウンロード (1118K) -
B. NAGENDER NATH, AKIO MAKISHIMA, JANINE NOORDMANN, RYOJI TANAKA, EIZO ...2009 年 43 巻 3 号 p. 207-216
発行日: 2009/06/20
公開日: 2011/04/19
ジャーナル フリーIn view of the requirement of a well-characterized and easily available aquatic sediment reference material, a comprehensive analysis comprising of fifty major, minor and trace elements as well as Sr-Nd-Pb-Hf isotopes were carried out in the stream sediment reference material, JSd-1, issued by the Geological Survey of Japan. The data for marine sediment reference material, MAG-1, issued by U.S. Geological Survey is also obtained for comparison. The elements were divided into two groups: Group I and Group II. Elements in Group I form stable soluble ions in HNO3; and those in Group II form soluble oxo- and fluoro-complexes in HF, such as Zr, Nb, Hf, Ta, etc. For Group I, the sample was decomposed with HF in a tetra fluoro ethylene (TFE) bomb at 245°C for 96 hrs with Mg addition. The elemental concentration was measured by quadrupole type inductively coupled plasma source mass spectrometry (ICP-QMS) and sector field type ICP-MS (ICP-SFMS) using isotope dilution-internal standardization (ID-IS) methods. The aliquot of the sample solution was passed through 3-step column chemistry for isotope ratio determination of Pb by multiple collector (MC) ICP-MS and thermal ionization mass spectrometry (TIMS), and Sr and Nd by TIMS. For Group II elements, the sample was decomposed with HF in a TFE bomb with the same time and temperature settings. Zr, Mo, Sn, Sb and Hf were determined by ID, and Nb and Ta by ID-IS using ICP-QMS. The original JSd-1 powder showed heterogeneity for Group II elements, indicating insufficient pulverization and distribution. Thus, we further pulverized the powder and measured the concentration, which showed improved homogeneity. The aliquot for the re-pulverized powder was passed through 2-step column chemistry, and the Hf isotope ratio was determined by MC-ICP-MS. Thus a new data on the trace elements as well as Sr-Nd-Pb-Hf isotope ratios is provided for JSd-1 and MAG-1 in this paper.抄録全体を表示PDF形式でダウンロード (137K)
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