Middle to late Eocene carbonate accumulation rates in the Pacific, Atlantic, Indian, and Southern Oceans

Sedimentary records from the equatorial Pacific show that the deepening of the carbonate compensation depth (depth below which the calcium carbonate flux to the seafloor is balanced by dissolution) at the Eocene/Oligocene boundary (~33.9 Ma) was preceded by several episodes of high and low carbonate accumulation rates. However, data from other basins are scarce. Here, we report middle-late Eocene carbonate accumulation rates from sites located in the Pacific, Atlantic, Indian, and Southern Oceans.

Our results show that the calcium carbonate burial was geographically, bathymetrically, and temporally heterogenous suggesting the fundamental role of surface calcium carbonate production in driving middle-late Eocene carbonate accumulation rates. Our data also suggest that an increase in ocean ventilation might have influenced calcium carbonate preservation at depths > 2500 m.