On 25th Sepember 2024, Mitsuki Ogasawara (D1), Takayuki Genda (M2), Ryosuke Matsunami (M2), and Shunsuke Mori (M2) , Kato, Nakamura, and Yasukawa Laboratory, Department of Systems Innovation, received  Student Outstanding Presentation Award at The 131st Annual Meeting of the Geological Society of Japan.

From left to right: Ogasawara-san, Mori-san, Genda-san, Matsunami-san

Student Outstanding Presentation Award at The 131st Annual Meeting of the Geological Society of Japan

The award is presented for outstanding presentations by student members at the academic conference organized by the Geological Society of Japan.

About awarded research

・Mitsuki Ogasawara

Title: Formation processes of Cu-Zn and Sn-W veins in the Akenobe polymetallic deposit, Hyogo Prefecture, Japan, based on Re-Os and U-Pb radiometric ages and Pb isotopic composition

Summary: The supply of metal resources is crucial for building a sustainable society, and a large portion of these resources comes from land-based mines. To discover more mines and increase the supply of metal resources, it is essential to elucidate the mechanisms of mine formation and establish promising exploration guidelines. In the awarded research, Re-Os, U-Pb, and U-Th-Pb radioactive decay series were utilized to estimate the magmatic activity that formed the Akenobe deposit in Hyogo Prefecture by determining its formation age and the origin of the metals. The research proposed a mechanism for the formation of the deposit.

・Takayuki Genda

Title: Development of a deep learning-based, high-precision detection method for seafloor hydrothermal signatures from AUV MBES data

Summary: We are conducting research on a method for automatically detecting hydrothermal activity on the seafloor from acoustic survey data obtained by a Multibeam Echo Sounder (MBES). Since MBES data contain an extremely low proportion of signals indicating hydrothermal activity, conventional automatic detection methods have faced the problem of frequent false positives. In this study, we propose a method that combines the output of an object detection model with a simple time series analysis, along with a new evaluation metric, and conducted evaluation experiments. As a result, we successfully significantly reduced the occurrence of false positives, and also demonstrated the potential effectiveness of this method for actual hydrothermal exploration. 　

・Ryosuke Matsunami

Title: Controlling factors for REE-rich mud formation based on an ocean-sediment Nd mass balance modeling: Implications for the genesis of high-grade REE-rich mud

Summary: We constructed a box model focusing on the mass balance of Nd in the ocean and sediments to investigate the conditions under which rare-earth element (REE)-rich mud is formed. In this presentation, we particularly discussed the effect of biogenic calcium phosphate, which is believed to significantly contribute to the formation of high-grade REE-rich mud.

・Shunsuke Mori

Title: Improvement of analytical methods for marine Os isotopes in deep-sea sediments by chemical leaching and efficient redox reactions -

Summary: The deep-sea sediments are not only important as a record of environmental changes and material cycles in the Earth's surface layer but are also garnering attention as a resource that concentrates rare earth elements (REE), which are indispensable for industry. Determining the age of these sediments is crucial for reconstructing past climates and paleoceanographic environments, as well as for elucidating the mechanisms of REE concentration to enable more efficient resource exploration. One method for estimating the age of sediments is based on osmium (Os) isotope stratigraphy. In this study, we conducted experiments aimed at establishing an accurate and simple analytical method, focusing particularly on the two points of Os extraction and oxidation methods. As a result, it was revealed that a chemical leaching method using hydrochloric acid can reduce the influence of detrital components more effectively than conventional methods, allowing for more accurate measurement of seawater-derived Os isotope ratios. Additionally, in the oxidation of Os using Teflon vials, it was suggested that the redox reactions of Os differ between sediment samples and standard solutions, highlighting the need for further investigation of optimal conditions for oxidation.

Your impression & future plan

・Mitsuki Ogasawara

I would like to express my deepest gratitude to Professor Kato, the members of the laboratory, the people of Yabu City in Hyogo Prefecture who cooperated in this research, the staff of Chiba Institute of Technology who supported the analysis, and the Hattori International Scholarship Foundation for their ongoing support, upon receiving this award. Moving forward, my immediate goal is to submit the results of this research to an international journal, and I will strive to bring you positive news as soon as possible. 　

・Takayuki Genda

I am truly honored to receive such a prestigious award. I would like to express my heartfelt gratitude to my supervisor, Professor Nakamura, the professors who guided my research, my co-researchers, and all the members of the laboratory who supported me. Encouraged by this award, I will continue to devote myself fully to further improving the precision of our methods and working towards their practical application. 　

・Ryosuke Matsunami

It is a great honor to receive such a prestigious award. I would like to express my deepest gratitude to Professor Yasukawa, Professor Nakamura, Professor Kato, and everyone else who has supported me. I will continue to dedicate myself to my research efforts in order to achieve new results. 　

・Shunsuke Mori

I would like to express my deepest gratitude to Professor Ota, Professor Yasukawa, Professor Nakamura, Professor Kato, and all those who have supported and advised me in my research upon receiving this award. I am extremely proud to receive such a prestigious honor. Moving forward, I will strive even harder in my research to produce results that can contribute to society.