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Hokkaido University Collection of Scholarly and Academic Papers (135.711 recursos)

HUSCAP (Hokkaido University Collection of Scholarly and Academic Papers) contains peer-reviewed journal articles, proceedings, educational resources and any kind of scholarly works of Hokkaido University.

Origin and Evolution of Natural Diversity

Mostrando recursos 1 - 10 de 10

  1. Preface

    Okada, H.; Mawatari, S.F.; Suzuki, N.; Gautam, P.
    International Symposium, "The Origin and Evolution of Natural Diversity". 1–5 October 2007. Sapporo, Japan.

  2. Preface

    Okada, H.; Mawatari, S.F.; Suzuki, N.; Gautam, P.
    International Symposium, "The Origin and Evolution of Natural Diversity". 1–5 October 2007. Sapporo, Japan.

  3. Preface

    Okada, H.; Mawatari, S.F.; Suzuki, N.; Gautam, P.
    International Symposium, "The Origin and Evolution of Natural Diversity". 1–5 October 2007. Sapporo, Japan.

  4. Depositional Environments Revealed From Biomarkers in Sediments Deposited During the Mid-Cretaceous Oceanic Anoxic Events (OAEs) in the Vocontian Basin (SE France)

    Okano, Kazuki; Sawada, Ken; Takashima, Reishi; Nishi, Hiroshi; Okada, Hisatake
    Biomarker and total sulfur (TS) analyses were carried out on laminated black shales and massive marls collected from Goguel level (OAE1a) and the Kilian and the Paquier levels (OAE1b) in the Vocontian Basin in southeast France. Total sulfur content and concentrations of thiophenes are abundant in the Goguel level, whereas furans and retene, which are originated from terrestrial plants, are predominant in the Kilian and the Paquier levels. These results suggests the expansion of intense anoxic waters to deep ocean during the deposition of Goguel level rather than during the periods covered by the Kilian and the Paquier levels. In...

  5. Experimental Study of the Use of the Stable Isotopic Composition of Calcareous Microfossils in Shallow Marine Sediments for Reconstructing Paleoenvironment, and a Comparison with the MART Index

    Ishimura, Toyoho; Dick, Matthew H.; Takashima, Reishi; Hirose, Masato; Gautam, Pitambar; Nishi, Hiroshi; Tsunogai, Urumu
    For reconstruction of paleoenvironments using the isotopic compositions of shallow-water microfossils, especially benthic microfossils at high latitudes, difficulties arise due to variation in environmental factors, including seasonal temperature, depth, water currents, and habitat. In this study, we applied a microscale technique to determine stable carbon and oxygen isotopic ratios in shallow-water calcareous benthic microfossils (foraminifera and bryozoans), in order to choose suitable species for reconstructing paleoenvironmental changes in a Pleistocene shallow marine setting. We compared isotopic trends in Cibicides refulgens, a shallow water epibenthic foraminifer, with the mean annual range of temperature (MART) based on bryozoan analyses. We found no...

  6. Experimental Study of the Use of the Stable Isotopic Composition of Calcareous Microfossils in Shallow Marine Sediments for Reconstructing Paleoenvironment, and a Comparison with the MART Index

    Ishimura, Toyoho; Dick, Matthew H.; Takashima, Reishi; Hirose, Masato; Gautam, Pitambar; Nishi, Hiroshi; Tsunogai, Urumu
    For reconstruction of paleoenvironments using the isotopic compositions of shallow-water microfossils, especially benthic microfossils at high latitudes, difficulties arise due to variation in environmental factors, including seasonal temperature, depth, water currents, and habitat. In this study, we applied a microscale technique to determine stable carbon and oxygen isotopic ratios in shallow-water calcareous benthic microfossils (foraminifera and bryozoans), in order to choose suitable species for reconstructing paleoenvironmental changes in a Pleistocene shallow marine setting. We compared isotopic trends in Cibicides refulgens, a shallow water epibenthic foraminifer, with the mean annual range of temperature (MART) based on bryozoan analyses. We found no...

  7. Rockmagnetic Characterization of the Setana and Chiraigawa Formations in SW Hokkaido (Soebetsu River, Kuromatsunai)

    Gautam, Pitambar; Takashima, Reishi; Dick, Matthew H.; Kanamatsu, Toshiya; Rijal, Moti L.; Nishi, Hiroshi; Mawatari, Shunsuke F.
    Rockmagnetic investigations were conducted on sediments constituting the upper part of the Setana Formation and the Chiraigawa Formation, of Plio-Pleistocene age, exposed along the Soebetsu River in the vicinity of Kuromatsunai town, Hokkaido. Average mass-specific low-field magnetic susceptibility (χ) had the lowest value (15.2 x 10^[-8] m^3kg^[-1]) at one site in the Kuromatsunai Formation, but higher values represented by wide ranges of (26.1-132.2) x 10^[-8] m^3kg^[-1] and (135.6-870.1) x 10^[-8] m^3kg^[-1] characterized the Chiraigawa and Setana Formations, respectively. Magnetomineralogical analyses by isothermal remanence (IRM) acquisition, Curie temperature determinations, and electron microscopy aided with energy dispersive X-ray analysis suggest the presence...

  8. Rockmagnetic Characterization of the Setana and Chiraigawa Formations in SW Hokkaido (Soebetsu River, Kuromatsunai)

    Gautam, Pitambar; Takashima, Reishi; Dick, Matthew H.; Kanamatsu, Toshiya; Rijal, Moti L.; Nishi, Hiroshi; Mawatari, Shunsuke F.
    Rockmagnetic investigations were conducted on sediments constituting the upper part of the Setana Formation and the Chiraigawa Formation, of Plio-Pleistocene age, exposed along the Soebetsu River in the vicinity of Kuromatsunai town, Hokkaido. Average mass-specific low-field magnetic susceptibility (χ) had the lowest value (15.2 x 10^[-8] m^3kg^[-1]) at one site in the Kuromatsunai Formation, but higher values represented by wide ranges of (26.1-132.2) x 10^[-8] m^3kg^[-1] and (135.6-870.1) x 10^[-8] m^3kg^[-1] characterized the Chiraigawa and Setana Formations, respectively. Magnetomineralogical analyses by isothermal remanence (IRM) acquisition, Curie temperature determinations, and electron microscopy aided with energy dispersive X-ray analysis suggest the presence...

  9. Geology and Sedimentary Environments of the Pleistocene Setana Formation in the Kuromatsunai District, Southwestern Hokkaido, Japan

    Takashima, Reishi; Dick, Matthew H.; Nishi, Hiroshi; Mawatari, Shunsuke F.; Nojo, Ayumu; Hirose, Masato; Gautam, Pitambar; Nakamura, Keiichi; Tanaka, Takayuki
    The Pleistocene Setana Formation is exposed along the axial zone of the Kuromatsunai district, southwestern Hokkaido Island, and is divided into the Nakasato Conglomerate Member and Soebetsu Sandstone Member. The Nakasato Conglomerate Member consists of medium- to coarsegrained sandstone that accumulated in shoreface, delta, and channel systems. This member is correlated with the overlapping interval between the CN13b calcareous nannofossil zone and the Neogloboquadrina pachyderma (s) / Neogloboquadrina incompta planktonic foraminiferan zone, which indicates an age of 1.2-1.0 Ma. The Soebetsu Sandstone Member is made up of sandy siltstone to very fine-grained sandstone and includes several beds of shell concentrations....

  10. Geology and Sedimentary Environments of the Pleistocene Setana Formation in the Kuromatsunai District, Southwestern Hokkaido, Japan

    Takashima, Reishi; Dick, Matthew H.; Nishi, Hiroshi; Mawatari, Shunsuke F.; Nojo, Ayumu; Hirose, Masato; Gautam, Pitambar; Nakamura, Keiichi; Tanaka, Takayuki
    The Pleistocene Setana Formation is exposed along the axial zone of the Kuromatsunai district, southwestern Hokkaido Island, and is divided into the Nakasato Conglomerate Member and Soebetsu Sandstone Member. The Nakasato Conglomerate Member consists of medium- to coarsegrained sandstone that accumulated in shoreface, delta, and channel systems. This member is correlated with the overlapping interval between the CN13b calcareous nannofossil zone and the Neogloboquadrina pachyderma (s) / Neogloboquadrina incompta planktonic foraminiferan zone, which indicates an age of 1.2-1.0 Ma. The Soebetsu Sandstone Member is made up of sandy siltstone to very fine-grained sandstone and includes several beds of shell concentrations....

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