Radiometric dating holocene samples
There is a small difference in the natural atmospheric C levels in the southern troposphere are therefore usually lower than those in the northern troposphere, and the radiocarbon ages of terrestrial materials in the Southern Hemisphere for a particular period of time are usually older than those in the Northern Hemisphere.
The current internationally-ratified radiocarbon calibration curve for terrestrial samples from the Southern Hemisphere is SHCal04.
This curve covers the past 11,000 cal yr, which is based on the dendrochronologically-dated tree rings for the last millennium and on model ages for the remaining period.
Details Calibration of a radiocarbon age of 6550 ± 40 BP of a terrestrial sample from the Northern Hemisphere, using Int Cal04 calibration curve and Ox Cal program version 3.10.
1) with a known value of regional offset from the global marine model age for that sample, defined as R and R of a location are usually assumed constant through time.
However, recent studies have reported variations of these values of several hundreds to a couple of thousands of years for several regions during Late Glacial and the Holocene.
An age offset between surface ocean and terrestrial samples is known as the marine reservoir age (R), which is ~400 yr on average (Fig. To calibrate a radiocarbon date for a surface ocean sample, one can use Int Cal04 curve with a known value of R.
Alternatively, one can use the current internationally-ratified marine calibration curve Marine04 (Fig.