Radiation-chemical processes leading to origination and accumulation of oxygen in the Earth’s atmosphere

Abstract

The role of natural radioactivity in the formation of the oxygen atmosphere of the Earth is discussed. The origination of oxygen in the free state in the hydrosphere and atmosphere is associated with the radiolysis of the water of the World ocean under the irradiation of radio active isotopes ⁴⁰K, ²³⁵U, ²³⁸U, and ²³²Th. The calculations showed that within the last 3.8 billion years the total weight of oxygen, which could be formed due to this process, is about 7.4•10¹⁷ kg, i.е., the value of the same order as the oxygen content in the modern atmosphere of the Earth. The Ocean was an intermediate collector and provided the nucleation of new forms of biological life with oxygen respiration. The consecutive transformation of the Earth’s atmosphere with a gradual increase in the oxygen content became the result of photosynthesis in algae and green plants and thus opened a way to the origination of complicated forms of the life.