Notation combines usages developed in the 1970s and 1980s (Kra and Stuiver 1986) whereby bp/ad/bc represent uncalibrated radiocarbon ages, AD/BC represent calendrical dates, and CalAD/CalBC/CalBP represent calibrated radiocarbon ages. Uncalibrated radiocarbon dates are denoted here as:
| bp | radiocarbon scientists' BP |
|---|---|
| ad | 1950 less the radiocarbon age if <1949 |
| bc | radiocarbon age if >1950, minus 1949 |
Calibrated dates (the radiocarbon age related to or calibrated to the AD/BC timescale) are denoted hereas:
| CalAD | RC age calibrated and falling within the calendrical AD timescale |
|---|---|
| CalBC | RC age calibrated and falling within the calendrical BC timescale |
Calendrical dates are denoted as conventional AD/BC and will be used to refer to broad periods of the calendrical timescale or to historically or astronomically fixed dates. While this appears to set aside the international scientific BP notation, that notation can be restored by replacing bp by BP, or by subtracting the ad date from 1950 and restoring BP, or by adding 1949 to the bc date and restoring BP.
When a radiocarbon date is quoted, the normal notation will be the uncalibrated bc date down to c. 1500bc, and for later bc dates the calibrated AD/BC date followed by the uncalibrated ad/bc radiocarbon age. This notation allows the conventional AD/BC timescale reference to be used from the time that calendrical dates become more securely available, without losing the radiocarbon age. This could be important if there are changes in calibration of radiocarbon ages in future, and will allow recalibrated AD/BC dates to be substituted.
For the purposes of this work, chronology for the period 3500bc-AD43 for southern Britain is divided into five periods. Select the links provided for a fuller overview.
3500-2500bc - Earlier Neolithic [CalBC 4340-3045]
2500-14/1300bc - Neolithic-Bronze Age Interface [CalBC 3045-1674/1522]
14/1300-8/700bc - Bronze Age [CalBC 1674/1522-906/813]
8/700-100bc - Iron Age [CalBC 906/813-92]
100bc-AD43 - Continental Transition [CalBC92-AD43]
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| File last updated: Wed Nov 7 2001