研究者業績

Koji Uno

  (宇野 康司)

Profile Information

Affiliation
Professor, School of Human Science and Environment, University of Hyogo
Degree
博士(理学)(神戸大学)

Researcher number
10510745
J-GLOBAL ID
201801009422849969
researchmap Member ID
7000024521

Papers

 43
  • Koji Uno, Hayao Morinaga
    Journal of the Geological Society of Japan, 129 663-671, Dec, 2023  Peer-reviewed
  • Koji Uno, Honoka Ohara, Kuniyuki Furukawa, Tatsuo Kanamaru
    Geoscience Letters, 10 21, Apr, 2023  Peer-reviewed
    Abstract To test the hypothesis that a Cretaceous hairpin turn is absent in the apparent polar wander path (APWP) of the inner arc of southwestern Japanese island (southwest Japan), we refined a mid-Cretaceous (100 Ma) paleomagnetic pole from southwest Japan. Red mudstone samples from the 100 Ma Hayama Formation were collected for paleomagnetic analysis from eight sites in the Hayama area in the central part of southwest Japan. A high-temperature remanent magnetization component carried by hematite was isolated from these sites and was found to be of primary mid-Cretaceous origin. The primary nature of the magnetization is supported by the detrital character of the magnetic carrier. The primary directions provided a paleomagnetic pole (35.0°N, 209.6°E, A95 = 6.1°, N = 8), which represented southwest Japan at 100 Ma. This pole falls into a cluster of Cretaceous poles in southwest Japan. An APWP for southwest Japan between 110 and 70 Ma was updated to ascertain the stationarity of the pole positions for this region. Therefore, it is unlikely that the APWP for southwest Japan experienced a hairpin turn during the Cretaceous.
  • Yoshihiro Sawada, Koji Uno, Tetsuya Sakai, Hironobu Hyodo
    Bulletin of Volcanology, 85 26, Apr, 2023  Peer-reviewed
  • Kuniyuki Furukawa, Koji Uno, Yu Horiuchi, Shintaro Murohashi, Motohiro Tsuboi
    Volcanica, 4 107-134, Jul, 2021  Peer-reviewed
    This study presents a description of a rhyolite lava-forming eruption, including the conduit system, degassing history during the lava flow dynamics. We examined the Pleistocene Shiroyama rhyolite lava on Himeshima Island, Japan. The lava is mainly characterized by locally developed obsidian. Based on the structural variation, the obsidian lithofacies correspond to the shallow conduit. The geological investigation and FTIR analyses showed that gas removal from the conduit magma proceeded via vesiculation, fracturing, and brecciation, allowing formation of the dense obsidian. Since the lava originally maintained some extent of water, the lava effervesced just after the effusion. This vesiculation resulted in pervasive bubble coalescence and the formation of abundant permeable pathways. The volcanic gasses escaped via those pathways, allowing collapse of the bubbles and deflation of the lava. AMS (anisotropy of magnetic susceptibility) results indicate that the lava spread concentrically.
  • Koji Uno, Yuta Idehara, Daichi Morita, Kuniyuki Furukawa
    Earth, Planets and Space, 73 132, Jun, 2021  Peer-reviewed

Presentations

 6

Research Projects

 10

Media Coverage

 2