Sediments In Japan Research Articles

Quantitative analysis of heavy elements and semi‐quantitative evaluation of heavy mineral compositions of sediments in Japan for construction of a forensic soil database using synchrotron radiation X‐ray analyses

We have started to construct a nationwide forensic soil sediment database for Japan, based on the heavy mineral and trace heavy element compositions of stream sediments collected at 3024 points across Japan. The data were measured by high‐resolution synchrotron radiation X‐ray powder diffraction (SR‐XRD) and high‐energy SR X‐ray fluorescence analysis (XRF) using the SR source of SPring‐8, the SR radiation facility in Japan. The automated sampling systems allow the measurement of 130 powder diffraction patterns and 100 XRF spectra per day using sediment samples of just a few milligrams, which enabled us to construct a database of a large number of samples. The concentrations of heavy elements such as rare earth elements, Cs and W up to 500 ppm level in soil sediments can be determined by the calibration curve method by using high‐energy SR‐XRF utilizing monochromatic X‐rays of 116 keV. A heavy element concentration map superimposed on a geographical map of Japan was successfully prepared from these analytical data. The heavy mineral compositions were quantitatively evaluated by using the peak intensity of characteristic XRD peaks of the component minerals measured by a Debye–Scherrer camera having a radius of 286.5 mm, recorded with an imaging plate and monochromatic X‐rays (λ = 1.0 Å). This study demonstrates that XRF and XRD data collected from the sediments of Shizuoka Prefecture closely reflect the geological and geographical signature of the sediment samples, which can be used for the provenance determination of soil evidence from a crime scene. Copyright © 2013 John Wiley & Sons, Ltd.

Development of deep-seated gravitational slope deformation on a shale dip-slope: Observations from high-quality drill cores

Abstract We analyzed high-quality drill cores with 100% recovery drilled into a gravitationally deformed dip-slope of a shale-dominated sequence of sediments in Japan. The slope had undulating surfaces but no well-defined landslide scarps, suggesting that parts of the slope had undergone gravitational deformation but had not completely separated from the surrounding bedrock. The gravitational deformation of shale and sandstone is characterized by disintegration and brecciation of sediments and the formation of pulverized zones with poorly developed planar structures, jigsaw-like structures, and fracture openings. Shear zones are distributed intermittently within the slope but have not merged discernably into a through-going master sliding surface. Incipient landslide shear zones form openings within coherent rock by shearing along bedding, with these shear zones potentially developing downward in a stepwise manner, which may be related to stress redistribution induced by river incision.

日本における湖沼掘削

The author reviews scientific drilling projects investigating lacustrine sediments in Japan. The lake sediments are excellent archives for paleoenvironments and tectonic movements, and are especially useful when sediments have sequences of annual bands. The earliest deep drilling projects, namely 200 m and 1,400 m drillings, were performed at Lake Biwa in 1971 and 1982-1983, respectively. The results revealed detailed climate changes and tectonic movements of the Omi basin over the past 1.6 Ma. Sediment cores from Lake Suigetsu provide an excellent chronological key based on annual bands for the past 50 ka or more. Furthermore, studies on sediment cores from Lake Nojiri and the lacustrine Takano Formation provided high time resolution data on paleoclimate for the past 160 ka: these data are based on the total organic carbon content and pollen composition of the sediment cores. The impregnation method to make a thin section of lake sediment is essential for counting annual layers to avoid miscounting varves. Lacustrine sediments exposed on land may also be useful archives of the Pleistocene as shown by case studies on Takano and Yoshino Formations. Sample storage systems and sub-sampling method such as double-L channel are useful for systematic research on sediments.

Marine Thalassiosira species from coastal Pleistocene sediments in central Kanto Plain, Japan

Nineteen species of the diatom genus Thalassiosira Cleve, including two tentatively identified and three unidentified species, are recorded from two sediment cores, drilled in Pleistocene coastal sediments of the Kanto Plain, central Japan. Concise descriptions obtained from the light and scanning electron microscopes are provided for the 19 Thalassiosira taxa recorded. This is the first study systematically investigating the taxonomy of the genus Thalassiosira and detailing the stratigraphic distribution of each taxon from Pleistocene coastal sediments of Japan. The species diversity of the genus Thalassiosira in the Japanese Pleistocene coastal environment is as high as in recent coastal waters.

Development of heavy mineral and heavy element database of soil sediments in Japan using synchrotron radiation X-ray powder diffraction and high-energy (116keV) X-ray fluorescence analysis

We have started the construction of a nationwide forensic soil sediment database for Japan based on the heavy mineral and trace heavy element compositions of stream sediments collected at 3024 points all over Japan obtained by high-resolution synchrotron X-ray powder diffraction (SR-XRD) and high-energy synchrotron X-ray fluorescence analysis (HE-SR-XRF). In this study, the performance of both techniques was demonstrated by analyzing soil sediments from two different geological regions, the Kofu and Chiba regions in Kanto province, to construct database that can be applied in the future to provenance analysis of soil evidence from a crime scene. The sediments from the quaternary volcanic lithology of the Chiba region were found to be dominated by heavy minerals of volcanic origin - orthopyroxene, clinopyroxene, and amphibole, and the REEs (rare earth elements) within the region showed similar geochemical behavior. On the other hand, four distinct heavy mineral groups were identified in the sediments of the Kofu region, where there is a great variety of underlying bedrock, and the geochemical behavior of the REEs in the sediments also varied accordingly to their geological origins. As such, our study shows that high-resolution SR-XRD data can provide information on the spatial distribution patterns of heavy minerals in stream sediments, playing an important role in determining their likely geographical origin. Meanwhile, the highly sensitive HE-SR-XRF data allow us to study the geochemical behavior of trace heavy elements, especially the REEs in the sediments, providing additional support to further constrain the likely geographical origin of the sediments determined by heavy minerals.

Evaluation for the capillary-sealing efficiency of the fine-grained sediments in Japan

Abstract For the geological storage in Japan, it is important to evaluate the capillary sealing efficiency of relatively younger sediments. The capillary sealing efficiency is influenced by the interfacial tension between gas and water system and by the representative diameter of the pores. As for the fine-grained sediments in Japan, the porosities are large, while the representative diameters of the pores are relatively small. These gaps are caused by the micro fabric of the fine-grained sediments such as clay that was formed during sedimentation in marine. Also, a case study was done for the storage capacity and leakage probability in Osaka Bay area. The results revealed that multiple sealing layers, formed under glacio-eustatic sea-level fluctuations, would prevent the CO 2 leakage during the millennium.

Cryptic Diversity of Free‐Living Parabasalids, Pseudotrichomonas keilini and Lacusteria cypriaca n. g., n. sp., as Inferred from Small Subunit rDNA Sequences

Ultrastructural and molecular phylogenetic evidence indicate that the Parabasalia consists of seven main subgroups: the Trichomonadida, Honigbergiellida, Hypotrichomonadida, Tritrichomonadida, Cristamonadida, Spirotrichonymphida, and Trichonymphida. Only five species of free-living parabasalids are known: Monotrichomonas carabina, Ditrichomonas honigbergii, Honigbergiella sp., Tetratrichomonas undula, and Pseudotrichomonas keilini. Phylogenetic analyses show that free-living species do not form a clade and instead branch in several different positions within the context of their parasitic relatives. Because the diversity of free-living parabasalids is poorly understood, the systematics of these lineages is in a significant state of disarray. In order to better understand the phylogenetic distribution of free-living parabasalids, we sequenced the small subunit rDNA from three different strains reminiscent of P. keilini; the strains were isolated from different geographical locations: (1) mangrove sediments in Japan and (2) sediments in Cyprus. These data demonstrated that the free-living parabasalids P. keilini and Lacusteria cypriaca n. g., n. sp., form a paraphyletic assemblage near the origin of a clade consisting mostly of parasitic trichomonadids (e.g. Trichomonas vaginalis). This paraphyletic distribution of similar morphotypes indicates that free-living trichomonadids represent a compelling example of morphostasis that provides insight into the suite of features present in the most recent free-living ancestor of their parasitic relatives.

The Characteristics of OSL Signal from Quartz Grains Extracted from Modern Sediments in Japan

Quartz grains from sediments in Japan are derived from complex mixtures of sources, including volcanic, plutonic, metamorphic and sedimentary rocks. We have measured the OSL signal of quartz grains from modern coastal sediments derived from different source rocks and compared these characteristics with the likely source. Each sample shows a different combination of various OSL components. It is concluded that the source rock affects the characteristics of the OSL components from quartz grains in Japanese sediments. By comparing the LM-OSL signals from volcanic sources with those from various source rocks, it can be deduced that quartz which has a higher fast component ratio is more suitable for dating. We also conclude that volcanic source areas should be avoided.

Application of real-time PCR assays to genotyping of F-specific phages in river water and sediments in Japan

Genotyping of F-specific RNA phages is currently one of the most promising approaches to differentiate between human and animal fecal contamination in aquatic environments. In this study, a total of 18 river water and sediment samples were collected from the Tonegawa River basin, Japan, in order to describe the genogroup distribution of F-specific RNA and DNA phages using genogroup-specific real-time PCR assays. F-specific phages were detected in nine (100%) river water and six (67%) sediment samples. Eighty-five phage plaques were isolated from these samples and subjected to real-time PCR assays specific for the phages. F-specific RNA phages of human genogroups (II and III) were detected in 32 (38%) plaques, whereas those of animal genogroups (I and IV) were detected in 17 (20%) plaques. No correlation was observed between the genogroup distribution of F-specific RNA phages and the occurrence of human adenovirus genomes, suggesting that genotyping of the phages alone is inadequate for the evaluation of the occurrence of viruses in aquatic environments. SYBR Green-based real-time PCR assay revealed the presence of F-specific DNA phages in four (5%) plaques, which were further classified into two genogroups (fd- and f1-like phages) by sequence analysis. Thirty-two (38%) plaques were not classified as the F-specific phage genogroups, indicating the limited applicability of these real-time PCR assays to a wide range of aquatic environmental samples worldwide.

The development of Fe-nodules surrounding biological material mediated by microorganisms

Takashikozo is a phenomenon of Quaternary sediments in Japan. They are cylindrical Fe-oxyhydroxide nodules that form as plaques round plant roots, where Fe is preferentially concentrated to develop a solid wall. Struc- tural features suggest that after the roots have decayed, the central space where the roots were situated acts as a flow path for oxidized water. Analysis of microbial 16S rDNA extracted from the nodules identified iron-oxidizing bacte- ria encrusted round the roots where they are the likely initiators of nodule formation. Direct microscopic obser- vation revealed an accumulation of Fe-oxyhydroxides that fill the pore spaces and is also likely to be linked with the encrusting microbial colonies. Geological history and nanofossil evidence suggest that these Fe-nodules may have been buried at a depth of up to several tens of meters for at least 10 5 years in reducing Quaternary sediments. Thus Fe- oxyhydroxide nodules that have formed in a geological environment at the interfaces between water and rock by microbial mediation can persist under reducing conditions. If this is the case, the phenomenon is significant as an analogue of post-closure conditions in radioactive waste repositories, since it could influence nuclide migration.

Terrestrial Records of the Latest Gauss Cooling Event in Japan and North Central China

Stratigraphic studies of magnetic polarity, paleobotany, and paleoenvironment using Plio-Pleisotocene terrestrial sediments in Japan and north central China were reviewed to investigate climate changes around the Gauss-Matuyama magnetic polarity boundary (GMB). Pollen and plant macrofossil data from Osaka, Aizu, and Tokachi in Japan show an extensive floral change associated with cooling in the latest Gauss chron, which is the largest in scale during the last 3-5 million years. The floral change occurred within a zone just below the GMB, where warmer elements disappeared stepwise and new cooler elements emerged also stepwise. In Tokachi, northern Japan, a long-term warmer climate that began at about 3.7Ma terminated just before the GMB, followed by recovery of a boreal climate. In the Chinese Loess Plateau, the GMB occurs around the loess/red clay boundary (LRB). However, the GMB lies at various depths ranging from 5m to -4m above the LRB, which is too wide to be explained by downward displacements due to delayed acquisition of post-depositional remanent magnetization. Local climates may have originated regional variability in lithology. The strong cooling event predating both the GMB and the LRB is consistent with that observed in Japan. Magnetic susceptibility of the red clay suggests occurrence of a long-term warm-moist climate from 3.4Ma to 2.75Ma, which may be related to that in Tokachi.

Climate system transition from glacial to interglacial state around the beginning of the last termination: Evidence from a centennial‐ to millennial‐scale climate rhythm

A periodic variation on a centennial to millennial scale was observed in the manganese and iron contents of Lake Suigetsu sediments in Japan, dating from 19.0 to 5.7 cal. kyr B.P. (calibrated thousand years before present). The increased manganese and iron contents, which mainly indicate the relative abundance of siderite, result from a greater vertical circulation in the lake during a cold period, with a higher mass of manganese and iron oxide being precipitated. The cold periods inferred from the increased manganese and iron contents coincide with the timing of ice‐rafting debris (IRD) events in the North Atlantic, which span from the last termination to the Holocene, suggesting that the climate shift was hemispheric or probably global in nature. The manganese variation resembles the residual atmospheric 14C production (Δ14C) data of the Holocene that reflect variation in solar activity, and its periodicities correspond with those of solar‐related climate changes from paleoproxy records in the North Atlantic and East Asia from the last cold stage to the Holocene. In particular, the Mn variation was larger in amplitude and shorter in timescale during the last cold stage when compared with those during the last termination and the Holocene, thereby possibly showing a significant difference in climate response to solar irradiance. The transition of the climate system from a glacial to an interglacial state corresponds to the beginning of the last termination.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in paddy soils and river sediments in Akita, Japan

Paddy soils and sediments from the Yoneshirogawa, Omonogawa, and Koyoshigawa River Basins in Akita were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The levels and compositions in those samples including soils from non-agricultural areas (non-agricultural soils) were investigated using isomer-specific analysis to determine characteristic sources. The PCDD/PCDF compositions in the samples were compared with respect to possible sources. The PCDD/PCDF concentrations in paddy soils were much higher than those in the non-agricultural soils and much higher than those found in other parts of Japan. Although PCDD/PCDFs were ubiquitous in sediments from river sources to mouths of the respective river basins, those concentrations were much lower than those from paddy soils and non-agricultural soils, and from other parts of Japan. Comparison of PCDD/PCDF homologues and isomer compositions for samples indicated that compositions of paddy soils and sediments, except for those from river sources, had similar characteristics to PCDD/PCDFs originating from impurities in herbicides, 2,4,6-trichlorophenyl 4-nitrophenyl ether (CNP) and pentachlorophenol (PCP), and that compositions of river-source sediments and non-agricultural soils resembled those of atmospheric depositions. Results of statistical analyses suggest that PCDD/PCDF contamination of paddy soils and sediments is attributable mainly to three sources: CNP, PCP, and atmospheric deposition. Results of this study also demonstrate that CNP and PCP are not only important contaminants of local areas of Japan, but that they exist throughout Akita, in northern Japan. We therefore conclude that PCDD/PCDF pollution caused by those compounds has a widespread influence on paddy soils and river sediments in Japan.

Quartz and polymineral luminescence dating of Japanese loess over the last 0.6 Ma: Comparison with an independent chronology

There are only a few luminescence dating studies of loess sediments in Japan, but interleaved with these deposits are many well-described tephras of known age based on 14C and fission track analysis; these independent age controls provide an opportunity to test the reliability of loess luminescence ages. This study provides such a comparison at two sites in central Honshu, the largest island in the Japanese archipelago. Samples were collected from sequences of interleaved volcanic tephra and loess deposited on a Middle Pleistocene river terrace in the Niigata Prefecture and on an Early to Middle Pleistocene dissected fluvial surface at in the Tochigi Prefecture, Honshu. Equivalent doses (De) were estimated from fine grains (4–11 μm) using both polymineral IR-OSL and (post-IR) blue-OSL, and quartz blue-OSL. The blue-stimulated luminescence signals could be represented by up to three exponentially decaying components; only the most light sensitive of these components was used in the final De estimation. Almost all the estimates of De from polymineral IR-OSL are smaller than those from polymineral (post-IR) blue-OSL and quartz blue-OSL, whereas the latter two are in good agreement. The blue-light stimulated luminescence ages using the most light sensitive component are shown to be in good agreement with the independent control, up to 500 ka. Although the IR-OSL signals underestimate the known age, a simple laboratory fading test is found empirically to correct for this underestimation. We conclude that the most rapidly blue-stimulated luminescence signals from quartz extracted from our loess samples give reliable ages, and that future loess dating studies should concentrate on these signals.

Scanning electron microscopy and sulfur isotopic characterization of pyrite in silicified wood fragment in Japan.

Five samples of fine-grained, authigenic pyrite seams in silicified woods from Tertiary marine to brackish sediments in Japan were examined on surface morphology by scanning electron microscopy (SEM) in combination with energy dispersive X-ray spectrometry (EDX) and on sulfur isotopic composition (δ34S). The surface morphology as revealed by SEM varied from long fibrous (pseudomorph after original plant fiber), spongy, blocky/cubic to framboidal (spherical aggregates of minute crystals). Except two samples from Chikuho coal mine area in northern Kyushu (Ebitsu: spongy fabric, δ34S=+3.5‰, +12.2‰), all pyrite samples were characterised by fairly low δ34S values ranging from −40.0 to −20.1‰, suggesting to be the products from steady state sulfate reduction, under an open system, of seawater-sulfate by sulfate-reducing bacteria. Pyrite in coal deposits from the Ebitsu area is also bacteriogenic, but probably formed under a closed system where original plant debris were deposit. Any clear trend between surface morphology and δ34S of the pyrite was not found.

日本の間氷期堆積物に含まれる サルスベリ属Lagerstroemia 花粉化石の形態

日本の間氷期堆積物に含まれる サルスベリ属Lagerstroemia 花粉化石の形態

Further application of the deconvolution method of post-depositional DRM to the precise record of the Matuyama-Brunhes reversal in the sediments from the Boso Peninsula, Japan

The Matuyama-Brunhes geomagnetic reversal was continuously recorded in the massive siltstones of the Boso marine sediments in Japan with the time resolution better than 9 years. However the Boso sediments probably have the post-depositional detrital remanent magnetization (pDRM) depressing short-period variations due to the convolution of the geomagnetic field. The previous application of the deconvolution method of pDRM to the 900 year records gave the half fixing depth of 21 cm. Further application of this fixing depth to the 4100 year record clearly shows nearly 100 year variations in both of the inclination and declination.

｀１２９´Ｉ法による間隙水の年代測定と石油探鉱への応用

Radioactive 129I method is very useful for petroleum exploration. 129I is naturally produced by cosmic-ray-induced spallation of 129Xe in the upper atmosphere, and by spontaneous fission of 238U in the Earth's crust.129I dating method gives an isolation age of interstitial water from the sea to the sedimentary system. A half-life of 129I is 15.7m.y., so that its application age is restricted between 3 to 90Ma. This is the first and the only geochronologic method to determine the age of fluid in the Tertiary sedimentary basin, while conventional methods are available only for solid or younger fluid. An application to U.S. Gulf Coast basin (Moran et al., 1995) revealed vertical migration of brine from older, deeper sources to present young host formations.Another application of fissiogenic 129I as a tracer in Paleozoic Anadarko basin, Oklahoma (Moran, 1996), to determine the source rock was also presented.129I dating method will be expected to give geochemical evidences about fluid migration in the basin, and resolve the genetics of dissolved-in-water type iodine-natural gas deposits in Neogene to Quaternary sediments in Japan.

Varved Lacustrine Sediments in Japan : Recent Progress.

Annually laminated (varved) lacustrine sediments provide a potentially continuous, high-resolution records of the last glacial and Holocene paleoenvironments. In 1991-1993, long sequences of laminated lacustrine sediments were successfully taken from two lakes in southwestern Japan, Lake Suigetsu and Lake Tougouike. Based on lamina counting and AMS 14C dating, we clarified that these laminated sediments were varves. Clay mineral composition in these varved sediments would be reflected by eolian dust concentrations, transported from Chinese Loess Plateau, and by precipitations around both lakes. Also, formation of iron sulfides and carbonates in varves would be caused by cyclic changes of sea-water invasion, originated from sea-level changes. Annual to decadal oscillations of dust and iron mineral concentrations since the last glacial were detected in varved sequences of both lake sediments. These detailed sedimentological analysis of these sediments revealed varve chronology, process of varve formation and annual to decadal changes of sea-level and climate. Some of the climatic changes may correlate with abrupt changes (Younger Dryas and Heinrich events) observed in Greenland ice cores and marine sediments.

THE RESPONSE OF LOW AND HIGH SWELLING SMECTITES TO SODIC CONDITIONS

Swelling and dispersion of clays are the primary processes responsible for the degradation of soil hydraulic properties in the presence of exchangeable Na. The relative importance of these processes was evaluated by studying the response of low and high swelling smectites to sodic conditions. Smectite from Ariake bay sediments in Japan represented the low swelling smectite, and clay from the Kamenose landslide in Japan represented the high swelling smectite. Changes in hydraulic conductivity (HC) and clay dispersivity of sediment-sand mixtures (10, 20, and 30 g of sediment mixed with 90, 80, and 70 g of sand, respectively) as a function of total electrolyte concentration (TEC) (0.05 and 0.01 M Cl− and distilled water, (DW)) and sodium adsorption ratio ((SAR) of 0, 10, and 20) of the percolating solutions were measured. In the low swelling smectite, no changes in HC were measured in the electrolyte solutions (TEC ≥ 0.01 M Cl−) at the three SAR values. When the low swelling smectites were leached with DW, the HC of the Ca-smectite increased, whereas the HC of the SAR 10 and 20 treatments decreased. Clay dispersion and migration out of the 10% soil column was substantial. The increase in HC in Ca-mixture of low swelling smectite leached with dilute solutions was attributable to the collapse of the open microstructure that prevails in electrolyte solutions. In low swelling smectite, clay dispersion was the main process responsible for HC deterioration under sodic conditions, and smectite dispersion was prevented when TEC exceeded the flocculation value of the clay. Clay dispersion increased with an increase in exchangeable sodium percentage (ESP), and it affected the HC of the porous media only when the pores were fine and the dispersed clay plugged the conducting pores. In the high swelling smectite mixtures, a gradual decrease in the HC was measured as the TEC decreased and the SAR increased. In these mixtures, swelling was the main process responsible for HC deterioration in electrolyte solutions with TEC ≥ 0.01 M Cl−. Swelling increased with an increase in clay percentage, ESP, and decreasing TEC.