Cenozoic carbonate burial along continental margins

Abstract

Marine carbonate burial represents the largest long-term carbon sink at Earth's surface, occurring in both deep-sea (pelagic) environments and shallower waters along continental margins. The distribution of carbonate accumulation has varied over geological history and impacts the carbon cycle and ocean chemistry, but it remains difficult to quantitatively constrain. Here, we reconstruct Cenozoic carbonate burial along continental margins using a mass balance for global carbonate alkalinity, which integrates independent estimates for continental weathering and pelagic carbonate burial. Our results indicate that major changes in marginal carbonate burial were associated with important climate and sea-level change events, including the Eocene-Oligocene transition (ca. 34 Ma), the Oligocene-Miocene boundary Mi-1 glaciation (ca. 23 Ma), and the middle Miocene climate transition (ca. 14 Ma). In addition, we find that a major increase in continental weathering from ca. 10 Ma to the present may have driven a concomitant increase in pelagic carbonate burial. Together, our results show that changes in global climate, sea level, and continental weathering have all impacted carbonate burial over the Cenozoic, but the relative importance of these processes may have varied through time.