Unraveling the mechanisms of generation and retention of "Manganese microparticle," a primary material of deep-sea manganese oxide minerals

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H04308
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: Kochi University
• Principal Investigator: Uramoto Goichiro 高知大学, 教育研究部総合科学系複合領域科学部門, 講師 (70612901)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 微小マンガン粒 / 酸化還元 / 物質循環 / X線顕微鏡 / 微小鉱物 / 微細構造

Outline of Final Research Achievements

Manganese is third most abundant metallic element in the Earth's surface and forms a oxic mineral deposit in the deep-seafloor environemt of the vast open ocean area. Manganese deposit is a concentrated containing rare metals, and it covers the seafloor. Manganese is prolific in the boundary region between the hydrosphere and lithosphere, and it is considered an important element for understanding the dynamics of metallic element cycling in the environment. However, the mechanism of manganese mineral formation and its abundant presence in the deep sea have remained uncertain.
This study aimed to establish a technological foundation for the precise analysis of manganese microparticles, which are considered to be the origin of manganese oxides in the deep-sea geological strata. Additionally, we identified the presence of manganese microparticles in various environmental samples and established the basis for understanding the universality of these particles throughout geological ages.

Free Research Field

堆積層序学

Academic Significance and Societal Importance of the Research Achievements

本研究では、地球規模の金属元素動態において重要な役割を果たすと考えられながら、これまで環境指標との有用性が確立されていなかった海底および海底地下の微小マンガン粒について、試料調製法や分析過程を改良することで、正確に化学状態を分析することを可能とした。また、これまで海底（下）試料のみから見出されていた微小マンガン粒を、陸上のマンガン鉱床の試料から見出した。
本研究で確立したアプローチ、および微小マンガン粒の環境中での存在は、その生成及び存在環境を示す地質指標としての有用性を示す基礎的な指標となると考えられる。