The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust, or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era.
The distance between scale markings on the horizontal scale is 100 km. Comparison of the vertical and horizontal scales indicates that the horizontal scale distance between tic marks is __<u>100</u>_ times that of the vertical scale.
