Hattori presented evidence in her Nature paper that, resolved the long-standing debate regarding the timing of the change in ancient Earths surface oxidation. Her findings demonstrated that atmospheric oxygen levels were still low around 2.4 billion years ago, during the early Proterozoic, based on detailed sulfur isotope analysis of sedimentary rocks on the north shore of Lake Huron. In her subsequent work published in Science', she revealed that atmospheric oxygen levels sharply rose within the sedimentary sequence at about 2.3 billion years.
Hattori also highlighted the role of volcanic processes in shaping the surface redox condition, challenging the previously held belief that increased photosynthesis was solely responsible for the oxidation of Earth's surface environment. Subsequent work provided further confirmation of the crystallization of oxidized magmatic sulfates during igneous crystallization, as well as the presence of such sulfate minerals in ancient (2.6 billion years old) igneous rocks.