Precambrian geology

An article in Science Advances reports the age of the oldest dated piece of cratonic mantle lithosphere (2.8 Ga), which was found at a mid-ocean ridge.

The Archaean atmosphere may have been well oxygenated, according to a reconsideration of sulfur cycling at that time. This challenges the view that sedimentary sulfur records oxygen-poor conditions during Earth’s first two billion years.

Differential cycling of carbonate and organic carbon in the mantle may link the Great Oxidation Event and the subsequent increase in carbon isotope values, according to a model that links the Earth’s surface and interior.

Subduction processes may have operated very early in Earth’s history according to the heavy silicon isotope compositions of Archaean igneous rocks. The silicon that precipitated out of the Archaean oceans as chert was subducted and melted to yield seawater-like heavy isotope signatures in early granitic rocks.