NEW AGES FOR NEOGENE MARINE BIOSTRATIGRAPHIC EVENTS

This paper introduces new development in the study of marine Neogene stratigraphy.Major stratigraphic boundaries in the international standard chronostratigraphic timescale published in 2004 are drawn on the basis of the 405ka long eccentricity cycles,indicating the arrival of a new era of orbital stratigraphy.In the new timescale,the Cenozoic Era now comprises E1 to E162 long eccentricity cycles,with the base dated at 65.5±0.3Ma,while the Neogene is now composed of E1 to E58 long eccentricity cycles from a base of 23.03Ma.Also obtained from orbital tuning is a series of new ages for paleomagnetic chrons and biostratigraphic events.Because some of these ages(especially those from the lower part of the Neogene) bear a difference of about 0.5Ma or more from earlier estimates,they are being summarized here for the purpose of updating and keeping up with the current international standard,as well as for strengthening the accuracy of high-resolution dating of marine Neogene strata.