An expanded shale δ98Mo record permits recurrent shallow marine oxygenation during the Neoarchean

Multiple attempts have been made using the ancient shale record to track the molybdenum isotope composition (δ98Mo) of seawater during the final two-hundred million years of the Archean Eon (2.7 to 2.5 billion-years-ago, or Ga). This seawater δ98Mo value is important because it should have scaled with levels of ocean oxygenation during the runup to the Great Oxidation Event (GOE). Unfortunately, however, it is difficult to tell if the majority...