Ancient Hindu - 360 day year, adding a month every 60 months to adjust to the solar year. At present an earth day is lengthening by an average of about 30 seconds a century as our moon's distance slowly increases. Ararat' is the Hebrew equivalent of the Assyro-Babylonian 'Urartu'. This is a region between the Upper Tigris and Aras rivers of northern Iraq and eastern Turkey which includes the massive volcanic peaks of the present day Ararat. It is here then, in this region of the southern Caucasus, that the Bible places the origin of all human civilization.
Chronology is a dangerous subject for study, because it can become an obsession, then a disease.
Please remember - the stylized nature of the Genesis Abrahamic genealogy means that the number of generations cannot be used for chronological purposes. The shift of this water mass triggers earthquakes throughout the region and migrations of tribes. World sea level is about 50 feet below present levels at this time. Date of Creation according to Bishop Usher, using genealogy as chronology. Date of Creation according to rabbinic Judaism.