Fusa Miyake

Associate Professor
Office for the Promotion of Transdisciplinary Network (OPTN) / Division for Cosmic-ray Research

Cosmic ray physics, Cosmogenic nuclide

We investigate past extreme solar events through high-temporal-resolution analyses of cosmogenic isotopes, such as carbon-14 in tree rings, and beryllium-10 and chlorine-36 in ice cores. We have identified signatures of these events, including the 774 CE and 993 CE events, as spikes in cosmogenic isotope data. Additionally, we explore on the application of these cosmogenic isotope spikes for achieving high-precision dating.

Masayo Minami

Office Manager・Professor
Office for the Promotion of Transdisciplinary Network (OPTN) / Division for Chronological Research / Center for International

Collaborative Research / Office for the Development of Interdisciplinary Research Strategy

Isotope geochemistry, Carbon-14 dating

My research focuses on radioisotope-based geochronology and geochemistry, emphasizing the development of advanced sample preparation methods for precise and accurate carbon-14 dating of geological and archaeological samples. I also investigate paleoclimatic changes and environmental dynamics using stable isotopes as tracers. This includes creating isotopic geochemical maps for provenance studies and historical analyses. I aim to further promote collaboration with researchers from diverse fields, both domestically and internationally.

En-Bi Choi

Researcher

Office for the Promotion of Transdisciplinary Network (OPTN)

Dendroisotope, Dendroarchaeology, Dendroclimatology, Wood Anatomy

I specialize in applying dendrochronology (a.k.a. tree-ring research) to archaeology (dendroarchaeology), climatology (dendroclimatology), and isotope studies (dendroisotope) focusing on dating and climate proxy research. For this purpose, I comprehensively deal with various information from tree rings, including tree-ring width, anatomical features, and isotopes. I especially focus on developing tree-ring isotope chronologies for dating and reconstructing paleoclimates. Through this work, I aim to integrate chronologies across East Asia to expand our understanding of relationships among climate variations and reconstruct spatiotemporal patterns of past environmental changes.

Minoru Sakamoto

Professor

The Graduate University for Advanced Studies

Scientific research on cultural properties, Radiocarbon dating

I am concerned with dating and interpreting historical and archaeological materials through radiocarbon. I am conducting radiocarbon dating of annual rings to refine a calibration curve based on Japanese trees while exploring techniques to enhance dating accuracy and precision. The current calibration curve, IntCal20, incorporates data collected by the National Museum of Japanese History, marking the first time that Japanese trees have been included.

Masataka Hakozaki

Associate Professor

Environmental chronology, Dendrochronology, Carbon 14 dating, Cultural properties, Paleoecology, Archaeobotany

We are measuring annual ring width, oxygen isotope ratios, and carbon 14 with high precision on tree-rings of living trees, excavated woods from archaeological sites, old building materials, and naturally buried woods in Japan and other parts of the world to determine the ages of archaeological sites, old buildings, and natural disasters, reconstruct paleoenvironment, restore solar activity, and construct basic data for dating.

Masaki Sano

Designated Associate Professor     

Paleoclimatology, Dendrochronology, Environmental history

I am involved in climate reconstructions from various parts of Asia using oxygen isotope ratios of tree rings, dating of old timbers, and environmental history research in collaboration with history and archaeology.

Reona Hiramine

Researcher

Quaternary geology, Tephrochronology, Geomorphology, Dendrochronology

I study the history of volcanic activity using the major element composition of volcanic glass shards in tephra. In particular, drift pumice I have studied is a clue to understanding the eruption history of submarine volcanoes. My research interests also include the application of dendrochronological methods to large-scale eruptions such as the Kikai-Akahoya and Towada-Hachinohe events. Going forward, by integrating dendrochronology with geomorphological and geological information, I aim to establish high-precision eruption ages and to contribute to a better understanding of volcanic disaster history.     

Fuyuki Tokanai

Professor

Astrophysics, Nuclear physics, Accelerator mass spectrometry, Carbon 14 dating

In 2009, Yamagata University (YU) installed a compact accelerator mass spectrometry (YU-AMS) system and an automated graphitization line dedicated to 14C measurement. Currently, we have been studying for in various fields, such as archaeology, environmental science, geology, and space and earth sciences using the YU-AMS system.

Tetsuya Shinozaki

Project Assistant Professor 

Sedimentology, organic geochemistry, paleoclimatology, Holocene, tsunami

The research interest is in the investigation of natural hazards and global environmental changes from the viewpoints of geochemistry, sedimentology, and geology, using mainly terrestrial sediment samples. In particular, my research topics are the reconstruction of historical and prehistoric tsunami magnitude and history using tsunami deposits, and the reconstruction of paleoclimate in the Holocene in East Asia using peat deposits.

Mitsuru Okuno

Professor

Volcanic geology, Radiocarbon chronology

I am conducting research to reconstruct the eruption history from tephra stratigraphy, volcanic geomorphology, and radiocarbon chronology. In addition to determining the eruption dates of active volcanoes in Japan, I am also conducting international collaborative research with national institutions in Korea, the Philippines, and Indonesia. I am also interested in the relationship between human dispersal and natural events such as volcanic eruptions, based on the relationship with archaeological remains in the Cook Islands and the Aleutian Islands.

Katsuhiko Kimura

Visiting Professor

Dendrochronology, Forest ecology

Dating old woods from various archaeological and geological sites using oxygen isotope dendrochronology.