Six global late Paleogene hiatuses (PHa to PHe) have been identified from deep-sea sequences. These hiatuses occurred at the middle/late Eocene boundary, late Eocene, Eocene/Oligocene boundary, late early Oligocene, late Oligocene, and Oligocene/Miocene boundary horizons.
Paleodepth distribution of hiatuses shows hiatus maxima characterized by major mechanical erosion below 4800 m, at mid-depth between 2000 and 3000 m, and in shallower water above 1600 m paleodepth. The geographic distribution and paleodepth of these hiatus maxima suggest that flow paths of major water masses and currents are the principal cause. Widespread short hiatuses due to carbonate dissolution or nondeposition occurred primarily during global cooling trends or climatic instability and appear to correlate to sea-level transgressions or onlap sequences. These hiatuses may have been caused by basin-shelf fractionation of carbonates.