New interpretation of oceanic eNd values recorded in manganese crusts in terms of diatomaceous ocean weathering: implication on the cause of the glacial-interglacial cycles

Abstract

In this study the oceanic εNd values recorded by manganese crusts are interpreted in terms of newly-identified diatomaceous ocean weathering as well as normal weathering carried out on lands (terrestrial weathering). The two types of weathering are assumed to be functions of oceanic silicic acid concentration and atmospheric CO2 concentration. The two environmental variables have been discovered to strongly be coupled most of time, but exhibit decoupling around 3 Ma ago. The implication will be discussed with relevance to the emergence of glacial periods.