Calendrical dating definition


The Long Count calendar keeps track of the days that have passed since the mythical starting date of the Maya creation, August 11, 3114 BCE.The Long Count date is written in column format as shown in the example on the left, with cycles of time as follows: .17.19 | 3 Kawak | 2 K'ank’in | G8 This date corresponds to December 20th, 2012 in the Gregorian calendar, and is read as follows: baktun.uinal.k’in | Tzolk’in | Haab | Lord of the Night Initial Series Introductory Glyph: This symbol identifies this date as belonging to the Long Count system Baktun: A number (12 in this example) along with the symbol of “baktun” Katun: A number (19 in this example) along with the symbol for “katun” Tun: A number (19 in this example) along with the symbol for “tun” Uinal: A number (17 in this example) along with the symbol for “uinal” K’in: A number (19 in this example) along with the symbol for “k‘in” Tzolk’in date: A number (3 in this example) along with the Tzolk’in day glyph (Kawak in this example) Haab date: A number (2 in this example) along with the Haab day glyph (K'ank’in in this example) Lord of the Night (G8 in this example): A glyph that represents one the nine deities of the Maya Underworld.The wood in these rings once laid down remains unchanged during the life of the tree.This is very useful as a record of the radiocarbon concentration in the past.



Any given date repeats at cyclic intervals, just as, for example, January 1st in the Gregorian calendar repeats every time the Earth completes a revolution around the Sun.See also ORAU's Explanation of Radiocarbon Results.Radiocarbon dates should always be reported either as `percent modern' or years `before present' (BP).The first indicates the proportion of radiocarbon atoms in the sample as compared to samples modern in 1950.

The second is directly derived from this on the assumption that the half-life of radiocarbon is 5568 years and the amount of radiocarbon in the atmosphere has been constant.

To extend this method further we must use the fact that tree ring widths vary from year to year with changing weather patterns.