Comment on "Molybdenum Isotope Evidence for Widespread Anoxia in Mid-Proterozoic Oceans"

Abstract

Arnold et al . ([ 1 ][1]) reported Mo isotope compositions of mid-Proterozoic black shale, which were different from those of euxinic sediments in the Black Sea. On the basis of a mass balance model calculation, they claimed that “the area of oxic sedimentation in the mid-Proterozoic oceans was