Depositional and diagenetic history of limestones and dolostones of the Oligo‐Miocene Kujung Formation in the Northeast Java Basin,Indonesia     

Muhlash Hada Firman Syah  Akihiro Kano  Tsuyoshi Iizuka  Yoshihiro Kakizaki 《Island Arc》2019,28(6)

Lithological and geochemical features of platformal carbonates record the signatures of the global climates and the regional environmental settings and also reconstruct the diagenetic history and porosity evolution, which are essential to evaluate the potential of hydrocarbon reservoirs. This study investigates the platformal carbonates of the Oligo‐Miocene Krunji Formation of North East Java Basin, which are potentially significant hydrocarbon reservoirs. The carbonate sequence in a 283 m thick section at Kranji in East Java is subdivided into three lithological units: limestone unit 1, dolostone unit 2, and limestone unit 3, in ascending order. The strontium‐isotope ratios of well‐preserved calcite samples indicate the depositional period from Chattian (late Oligocene) to Burdigalian (early Miocene), which is consistent with ages of the foraminifer assemblages. Unit 1 consists of low‐porosity limestone, in which two horizons of subaerial exposure are recognized by the occurrence of red‐colored matrix and lower δ¹³C values. Unit 2 consists of dolomitic rock and exhibits coarse‐grained calcitic grains and cross‐stratified structure. Considering that this unit has been subject to dolomitization, the sediment of unit 2 was initially permeable and was likely deposited in a shoal setting. The overlying unit 3 of Aquitanian–Burdigalian age is characterized by a highly granular texture. High porosity and uniformly low δ¹³C and δ¹⁸O values indicate that Unit 3 was subjected to more intense meteoric diagenesis than the Chattian unit 1. This was likely a consequence of the Antarctic ice‐sheet expansion during the Oligocene/Miocene transition, which amplified sea level change. The unit 2 dolomite has high δ¹³C and δ¹⁸O values and a high ⁸⁷Sr/⁸⁶Sr ratio which resulted from the reflux of seawater into permeable the sediment body in middle‐late Miocene (Burdigalian Tortonian) following the deposition of unit 3. The porosity and permeability of the Kujung Formation were initially controlled by sedimentological processes, but largely modified by later diagenetic processes.  相似文献   

Influence of microbial photosynthesis on tufa stromatolite formation and ambient water chemistry, SW Japan   总被引：1，自引：0，他引：1  

Fumito Shiraishi  Tomoyo Okumura  Akihiro Kano 《Geochimica et cosmochimica acta》2010,74(18):5289-17

Photosynthetic influences on tufa stromatolite formation and ambient water chemistry were investigated at two well-studied streams depositing tufa in Southwestern Japan (Shirokawa and Shimokuraida). The tufa stromatolites in both streams are composed of fine-grained calcite crystals showing annual lamination, and colonized by a number of filamentous cyanobacteria as well as non-phototrophic bacteria. Microelectrode measurements of pH, O₂, and Ca²⁺ near the stromatolite surface (the diffusive boundary layer; DBL) revealed that the investigated tufa stromatolites are formed by photosynthesis-induced CaCO₃ precipitation (PCP): cyanobacterial photosynthesis induces calcite precipitation under light conditions, while respiration of cyanobacteria and non-phototrophic bacteria inhibits precipitation in the dark. The bulk water chemistry at the lower sites of the investigated streams showed the daytime decreases of Ca²⁺ concentration and alkalinity that was expected for significant influence of PCP, while the other expected change, increased pH, was not observed. In order to examine this discrepancy, a novel approach using semi-in situ microelectrode measurements was applied to perform precise quantitative calculations. The calculation results demonstrated that the observed Ca²⁺ concentration and alkalinity decreases were caused by PCP, and that the concomitant pH increase was expected to be under the detection level of a conventional pH meter. Although the amount of PCP is supposed to be significantly affected by light intensity, observations in Shimokuraida revealed that the amount of PCP on cloudy day nonetheless accounted for about 80% of that on sunny day. Despite the significant role of PCP for tufa stromatolite formation, PCP accounted for only about 10% of the precipitated calcite in the investigated streams, which indicates that tufa stromatolites, the characteristic deposits in the streams, are responsible for only a small portion of calcite precipitation, and the rest is considered to precipitate inorganically at biofilm-free substrates.  相似文献   

Numerical Simulation of Crown Pillar Behaviour in Transition from Open Pit to Underground Mining     

Dintwe  Tumelo K. M.  Sasaoka  Takashi  Shimada  Hideki  Hamanaka  Akihiro  Moses  Dyson N.  Peng  Ma  Fanfei  Meng  Liu  Seifei  Ssebadduka  Ronald  Onyango  Joan A. 《Geotechnical and Geological Engineering》2022,40(4):2213-2229

Geotechnical and Geological Engineering - Crown pillars provide regional and local support by isolating the ground surface from underground mine workings. Topography above the underground mine may...  相似文献   

Statistical and Parametric Studies on Natural Levees as Weak Points Against Leakages in River Levees     

Zhang  Wenyue  Takahashi  Akihiro 《Geotechnical and Geological Engineering》2022,40(11):5643-5666

Geotechnical and Geological Engineering - Sandy natural levee deposits have been pointed out to provide seepage paths under river levees, which are largely related to the underseepage problems....  相似文献   

Sequences characterization of microsatellite DNA sequences in Pacific abalone (Haliotis discus hannai)     

Qi Li  Kijima Akihiro 《中国海洋大学学报(英文版)》2007,6(1):47-52

The microsatellite-enriched library was constructed using magnetic bead hybridization selection method, and the microsatellite DNA sequences were analyzed in Pacific abalone Haliotis discus hannai. Three hundred and fifty white colonies were screened using PCR-based technique, and 84 clones were identified to potentially contain microsatellite repeat motif. The 84 clones were sequenced, and 42 microsatellites and 4 minisatellites with a minimum of five repeats were found (13.1% of white colonies screened). Besides the motif of CA contained in the oligoprobe, we also found other 16 types of microsatellite repeats including a dinucleotide repeat, two tetranucleotide repeats, twelve pentanucleotide repeats and a hexanucleotide repeat. According to Weber(1990), the microsatellite sequences obtained could be categorized structurally into perfect repeats (73.3%), imperfect repeats(13.3%), and compound repeats (13.4%). Among the microsatellite repeats, relatively short arrays (＜ 20 repeats) were most abundant,accounting for 75.0%. The largest length of microsatellites was 48 repeats, and the average number of repeats was 13.4. The data on the composition and length distribution of microsatellites obtained in the present study can be useful for choosing the repeat motifs for microsatetlite isolation in other abalone species.  相似文献   

Factors controlling diurnal variation in the isotopic composition of atmospheric water vapour observed in the taiga,eastern Siberia     

Akihiro Ueta  Atsuko Sugimoto  Yoshihiro Iijima  Hironori Yabuki  Trofim C. Maximov  Tatiana A. Velivetskaya  Alexander V. Ignatiev 《水文研究》2013,27(16):2295-2305

Deciduous forest covers vast areas of permafrost under severe dry climate in eastern Siberia. Understanding the water cycle in this forest ecosystem is quite important for climate projection. In this study, diurnal variations in isotopic compositions of atmospheric water vapour were observed in eastern Siberia with isotope analyses of precipitation, sap water of larch trees, soil water, and water in surface organic layer during the late summer periods of 2006, 2007, and 2008. In these years, the soil moisture content was considerably high due to unusually large amounts of summer rainfall and winter snowfall. The observed sap water δ¹⁸O ranged from ?17.9‰ to ?13.3‰, which was close to that of summer precipitation and soil water in the shallow layer, and represents that of transpired water vapour. On sunny days, as the air temperature and mixing ratio rose from predawn to morning, the atmospheric water vapour δ¹⁸O increased by 1‰ to 5‰ and then decreased by about 2‰ from morning to afternoon with the mixing ratio. On cloudy days, by contrast, the afternoon decrease in δ¹⁸O and the mixing ratio was not observed. These results show that water vapour that transpired from plants, with higher δ¹⁸O than the atmospheric water vapour, contributes to the increase in δ¹⁸O in the morning, whereas water vapour in the free atmosphere, with lower δ¹⁸O, contributes to the decrease in the afternoon on sunny days. The observed results reveal the significance of transpired water vapour, with relatively high δ¹⁸O, in the water cycle on a short diurnal time scale and confirm the importance of the recycling of precipitation through transpiration in continental forest environments such as the eastern Siberian taiga. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Phototropic adjustment of the foliaceous coral Echinopora lamellosa in Palau     

Akihiro Iwase  Kazuhiko Sakai  Atsushi Suzuki  Robert van Woesik 《Estuarine, Coastal and Shelf Science》2008,77(4):672-678

We tested the hypothesis that foliose plates of Echinopora lamellosa (Esper, 1795) adjust their primary growth direction (or slope from the horizontal) when irradiance (light) is limiting. This hypothesis was tested at a coral-reef locality that is shaded daily by steep adjacent hills, restricting direct light to only a few hours each day (Iwayama Bay, Palau). The angle at which colonies received maximum light was measured using acetate film, and was compared with modeled estimates (using a simple global-light model). We show strong relationships between light and primary-colony gradients; with the foliose plates acting as parabolic antennae, predictably adjusting their primary gradients to optimize light capture.  相似文献   

DISTRIBUTION OF AEROSOL EXTINCTION IN THE LOWER TROPOSPHERE BY MICRO-PULSE LIDAR OBSERVATION^*     

WU Yonghu  HU Huanling  ZHOU Jun  Nobuo TAKEUCHI  Akihiro LICHIYAMA  Shoji ASANO 《Acta Meteorologica Sinica》2000,14(4):503-508

The profiles of aerosol extinction coefficients are investigated by micro-pulse lidar(MPL) combined with the meteorological data in the lower troposphere at Meteorological Research Institute(MRI).Japan.Larger extinction values of aerosol are demonstrated in the nocturnal stable air layer with larger Richardson number,and light wind velocities are favorable for aerosol concentrating in the planetary boundary layer(PBL).But aerosol extinction coefficients show larger values over the altitudes of 2.0 to 5.0km where correspond to higher relative humidity(RH).The tops of PBL identified by the aerosol extinction profiles almost agree with ones by radiosonde data.The diurnal variations of aerosol extinction profiles are clearly displayed,intensive aerosol layers usually are formed over the period of mid-morning to 1400 Loeal Time(LT).then elapse in the cloudless late afternoon and nighttime.Thermal eonvection or turbulent transport from the surfaee probably dominates these temporal and spatial changes of aerosol distribution.  相似文献   

Variation of Spectral Radiance of the Zenith Sky During the Annular Eclipse on May 21, 2012     

Hidehiko Suzuki  Akihiro Yamamoto 《Earth, Moon, and Planets》2013,110(3-4):157-163

The absolute brightness of the zenith sky was measured using a simple calibrated spectrometer during the annular solar eclipse event on May 21, 2012 in Fujioka City, Japan (36.2924°N, 139.0823°E). The sensitivity of the spectrometer was calibrated as a function of wavelength between 400 and 700 nm with an integral sphere. The brightness of the sky decreased to 6 % of its usual condition at the maximum magnitude of the annular eclipse of 0.95 for all wavelengths. The curve describing the variation of sky brightness accords well with the total luminosity of the solar disk estimated by a simple model that accounts for the limb darkening effect. This study provides zenith sky radiance as a function of wavelength and solar elevation angle, which is useful for the investigation of new optical instruments for atmospheric studies.  相似文献   

Simulating the carbon balance of a temperate larch forest under various meteorological conditions     

Motomu Toda  Masayuki Yokozawa  Akihiro Sumida  Tsutomu Watanabe  Toshihiko Hara 《Carbon balance and management》2007,2(1):1-18

This editorial provides a subject index from published articles, active researchers, and published papers in the field of carbon balance and management.  相似文献