The First Great Oxidation Event was likely a result of ____.
A) photosynthesis
B) oxygen production by zooplankton
C) a combination of biological and geochemical processes
D) accelerated weathering caused by lichens

Question

Quizplus · Accepted Answer

The First Great Oxidation Event was likely a result of a combination of biological and geochemical processes. Photosynthesis by cyanobacteria produced oxygen, which was then released into the atmosphere. This oxygen reacted with iron in the oceans, forming iron oxides. These iron oxides settled to the bottom of the oceans, removing iron from the water column and allowing oxygen levels to rise further.

The First Great Oxidation Event Was Likely a Result of ____