Carbonate sequestration in the Pacific, Indian and Atlantic oceans over the Cenozoic

Abstract

This thesis reconstructs the regional evolution of the carbonate compensation depth (CCD) across the Pacific and Indian oceans during the Cenozoic. Using lithological, carbonate, and paleo-depth data from DSDP, ODP, and IODP drill sites, regional CCD variability was modelled through time. The results reveal strong spatial differences linked to ocean circulation, tectonic gateway changes, Antarctic glaciation, atmospheric CO₂ fluctuations, and climate transitions. The Pacific Ocean records major Neogene CCD fluctuations associated with gateway reorganisations and the late Miocene biogenic bloom, while the Indian Ocean shows significant variability related to Indo-Pacific circulation and monsoon intensification. This thesis also presents the first basin-specific synthesis of carbonate accumulation rates across the Atlantic, Pacific, and Indian oceans since the Cretaceous, highlighting major inter-basin differences in pelagic carbonate burial. The findings demonstrate that long-term carbonate preservation and oceanic carbon storage were strongly controlled by tectonic evolution, deep-water circulation, and global climate change, providing new insights into the evolution of Earth’s carbon cycle and climate system through geological time.