During the Proterozoic era, oxygen produced by photosynthesizing bacteria collects in the oceans and then in the atmosphere. Iron present in exposed rocks reacts with this oxygen, and rust colors the ...

The Proterozoic record in southwestern North America documents a sequence of magmatic, deformational and metamorphic events that shaped the continent’s cratonic margin. Starting in the Mesoproterozoic ...

The geochronology of Proterozoic crustal development employs high-precision isotopic methods to unravel the timing, duration and tempo of crust formation, modification and assembly between 2.5 and 1.0 ...

The Proterozoic is a Precambrian eon of geologic time extending from about 2.5 billion to 541 million years ago, bounded by the Archean–Proterozoic and Proterozoic–Phanerozoic transitions. It is ...