1) Total amount of Earth’s water and its distribution mechanism

1-1) Water in the present lower mantle and core

1-2) Partitioning between interior and surface

2) Origin of water on Earth and in the solar system

2-1) Supply mechanism of water on Earth

2-2) Understanding of water in the solar system

3) Chemical compositions of initial atmosphere and ocean

3-1) Redox condition of atmosphere (H2/CH4/CO/CO2)

3-2) pH, alkalinity, and heavy metals of early ocean


We are trying to understand the origin and total amount of Earth’s water and chemical compositions in the very early atmosphere and ocean, which can give us information about the environment where life emerged on Earth. Collaboration among ELSI members from different fields, such as planetary science, geochemistry, and geophysics is the key to addressing these problems. We are constructing general models of planet formation and early Earth evolution with particular attention directed towards the behavior of volatile elements.


topic3_EIt is believed that the chemical composition of the initial Earth ocean and atmosphere fluctuated dynamically as a result of exterior influences.