Mantle Contributes To The Earth's Primitive Atmosphere

A study shows that the mantle, which is the layer between the crust and the outer core of the planet Earth, is linked with the evolution of the primitive atmosphere. This contributed to making the Earth breathable.

The study was published in the Nature Geoscience. It was led by Tingting Gu and Kanani K.M. Lee from Department of Geology and Geophysics, Yale University, Mingming Li from School of Earth and Space Exploration, Arizona State University and Catherine MacCammon from Bayerisches Geoinstitut, Universität Bayreuth. Researchers would like to know if the concentrations of atmospheric oxygen on Earth billions of years ago was influenced by the concentrations of oxygen in the mantle. They examined synthetic samples of the lower mantle to various high-pressure oxygen environments.

Kanani Lee, the principal investigator explained that when there's less oxygen present in the rock, it's denser than when there is more oxygen present, even though the rest of the elements are the same. The denser rocks settled down to the boundary between the mantle and the outer core. These became the colossal molten blobs, which can be found today underneath the African continent and the Pacific Ocean. The lighter rocks have risen to the upper mantle through plate tectonics or volcanic activity. The chemical reactions caused to mineralize the oxygen. This allowed it to be dispensed in the atmosphere.

The study indicates that the heterogeneous redox conditions in earth's interior can contribute to the large low shear velocity provinces in the lower mantle and the evolution of atmospheric oxygen. The upper mantle's oxidation would have happened around 3.6 billion years ago. It suggests that oxygen was built up then and culminated in the Great Oxygenation Event (GOE) 1.3 billion years later. This was bolstered by the agitating violence of the superheated mantle, according to IFL Science.

The mantle is a layer inside the terrestrial planets such as the Earth, Mars, Venus and Mercury and some other rocky planetary bodies. The mantle of the planet Earth is about 84 percent of Earth's volume. It is a silicate rocky shell with an average thickness of 2,886 kilometers.